/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp

Bug Summary

File:	tools/clang/lib/Sema/SemaTemplateDeduction.cpp
Warning:	line 3831, column 9 Called C++ object pointer is null

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/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp

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1//===- SemaTemplateDeduction.cpp - Template Argument Deduction ------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements C++ template argument deduction.
10//
11//===----------------------------------------------------------------------===//

13#include "clang/Sema/TemplateDeduction.h"
14#include "TreeTransform.h"
15#include "TypeLocBuilder.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/ASTLambda.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/DeclAccessPair.h"
20#include "clang/AST/DeclBase.h"
21#include "clang/AST/DeclCXX.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/DeclarationName.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/NestedNameSpecifier.h"
27#include "clang/AST/TemplateBase.h"
28#include "clang/AST/TemplateName.h"
29#include "clang/AST/Type.h"
30#include "clang/AST/TypeLoc.h"
31#include "clang/AST/UnresolvedSet.h"
32#include "clang/Basic/AddressSpaces.h"
33#include "clang/Basic/ExceptionSpecificationType.h"
34#include "clang/Basic/LLVM.h"
35#include "clang/Basic/LangOptions.h"
36#include "clang/Basic/PartialDiagnostic.h"
37#include "clang/Basic/SourceLocation.h"
38#include "clang/Basic/Specifiers.h"
39#include "clang/Sema/Ownership.h"
40#include "clang/Sema/Sema.h"
41#include "clang/Sema/Template.h"
42#include "llvm/ADT/APInt.h"
43#include "llvm/ADT/APSInt.h"
44#include "llvm/ADT/ArrayRef.h"
45#include "llvm/ADT/DenseMap.h"
46#include "llvm/ADT/FoldingSet.h"
47#include "llvm/ADT/Optional.h"
48#include "llvm/ADT/SmallBitVector.h"
49#include "llvm/ADT/SmallPtrSet.h"
50#include "llvm/ADT/SmallVector.h"
51#include "llvm/Support/Casting.h"
52#include "llvm/Support/Compiler.h"
53#include "llvm/Support/ErrorHandling.h"
54#include <algorithm>
55#include <cassert>
56#include <tuple>
57#include <utility>

59namespace clang {

/// Various flags that control template argument deduction.
///
/// These flags can be bitwise-OR'd together.
enum TemplateDeductionFlags {
  /// No template argument deduction flags, which indicates the
  /// strictest results for template argument deduction (as used for, e.g.,
  /// matching class template partial specializations).
  TDF_None = 0,

  /// Within template argument deduction from a function call, we are
  /// matching with a parameter type for which the original parameter was
  /// a reference.
  TDF_ParamWithReferenceType = 0x1,

  /// Within template argument deduction from a function call, we
  /// are matching in a case where we ignore cv-qualifiers.
  TDF_IgnoreQualifiers = 0x02,

  /// Within template argument deduction from a function call,
  /// we are matching in a case where we can perform template argument
  /// deduction from a template-id of a derived class of the argument type.
  TDF_DerivedClass = 0x04,

  /// Allow non-dependent types to differ, e.g., when performing
  /// template argument deduction from a function call where conversions
  /// may apply.
  TDF_SkipNonDependent = 0x08,

  /// Whether we are performing template argument deduction for
  /// parameters and arguments in a top-level template argument
  TDF_TopLevelParameterTypeList = 0x10,

  /// Within template argument deduction from overload resolution per
  /// C++ [over.over] allow matching function types that are compatible in
  /// terms of noreturn and default calling convention adjustments, or
  /// similarly matching a declared template specialization against a
  /// possible template, per C++ [temp.deduct.decl]. In either case, permit
  /// deduction where the parameter is a function type that can be converted
  /// to the argument type.
  TDF_AllowCompatibleFunctionType = 0x20,

  /// Within template argument deduction for a conversion function, we are
  /// matching with an argument type for which the original argument was
  /// a reference.
  TDF_ArgWithReferenceType = 0x40,
};
107}

109using namespace clang;
110using namespace sema;

112/// Compare two APSInts, extending and switching the sign as
113/// necessary to compare their values regardless of underlying type.
114static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) {
if (Y.getBitWidth() > X.getBitWidth())
  X = X.extend(Y.getBitWidth());
else if (Y.getBitWidth() < X.getBitWidth())
  Y = Y.extend(X.getBitWidth());

// If there is a signedness mismatch, correct it.
if (X.isSigned() != Y.isSigned()) {
  // If the signed value is negative, then the values cannot be the same.
  if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative()))
    return false;

  Y.setIsSigned(true);
  X.setIsSigned(true);
}

return X == Y;
131}

133static Sema::TemplateDeductionResult
134DeduceTemplateArguments(Sema &S,
                      TemplateParameterList *TemplateParams,
                      const TemplateArgument &Param,
                      TemplateArgument Arg,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced);

141static Sema::TemplateDeductionResult
142DeduceTemplateArgumentsByTypeMatch(Sema &S,
                                 TemplateParameterList *TemplateParams,
                                 QualType Param,
                                 QualType Arg,
                                 TemplateDeductionInfo &Info,
                                 SmallVectorImpl<DeducedTemplateArgument> &
                                                    Deduced,
                                 unsigned TDF,
                                 bool PartialOrdering = false,
                                 bool DeducedFromArrayBound = false);

153static Sema::TemplateDeductionResult
154DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
                      ArrayRef<TemplateArgument> Params,
                      ArrayRef<TemplateArgument> Args,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                      bool NumberOfArgumentsMustMatch);

161static void MarkUsedTemplateParameters(ASTContext &Ctx,
                                     const TemplateArgument &TemplateArg,
                                     bool OnlyDeduced, unsigned Depth,
                                     llvm::SmallBitVector &Used);

166static void MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
                                     bool OnlyDeduced, unsigned Level,
                                     llvm::SmallBitVector &Deduced);

170/// If the given expression is of a form that permits the deduction
171/// of a non-type template parameter, return the declaration of that
172/// non-type template parameter.
173static NonTypeTemplateParmDecl *
174getDeducedParameterFromExpr(TemplateDeductionInfo &Info, Expr *E) {
// If we are within an alias template, the expression may have undergone
// any number of parameter substitutions already.
while (true) {
  if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E))
    E = IC->getSubExpr();
  else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(E))
    E = CE->getSubExpr();
  else if (SubstNonTypeTemplateParmExpr *Subst =
             dyn_cast<SubstNonTypeTemplateParmExpr>(E))
    E = Subst->getReplacement();
  else
    break;
}

if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
  if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()))
    if (NTTP->getDepth() == Info.getDeducedDepth())
      return NTTP;

return nullptr;
195}

197/// Determine whether two declaration pointers refer to the same
198/// declaration.
199static bool isSameDeclaration(Decl *X, Decl *Y) {
if (NamedDecl *NX = dyn_cast<NamedDecl>(X))
  X = NX->getUnderlyingDecl();
if (NamedDecl *NY = dyn_cast<NamedDecl>(Y))
  Y = NY->getUnderlyingDecl();

return X->getCanonicalDecl() == Y->getCanonicalDecl();
206}

208/// Verify that the given, deduced template arguments are compatible.
209///
210/// \returns The deduced template argument, or a NULL template argument if
211/// the deduced template arguments were incompatible.
212static DeducedTemplateArgument
213checkDeducedTemplateArguments(ASTContext &Context,
                            const DeducedTemplateArgument &X,
                            const DeducedTemplateArgument &Y) {
// We have no deduction for one or both of the arguments; they're compatible.
if (X.isNull())
  return Y;
if (Y.isNull())
  return X;

// If we have two non-type template argument values deduced for the same
// parameter, they must both match the type of the parameter, and thus must
// match each other's type. As we're only keeping one of them, we must check
// for that now. The exception is that if either was deduced from an array
// bound, the type is permitted to differ.
if (!X.wasDeducedFromArrayBound() && !Y.wasDeducedFromArrayBound()) {
  QualType XType = X.getNonTypeTemplateArgumentType();
  if (!XType.isNull()) {
    QualType YType = Y.getNonTypeTemplateArgumentType();
    if (YType.isNull() || !Context.hasSameType(XType, YType))
      return DeducedTemplateArgument();
  }
}

switch (X.getKind()) {
case TemplateArgument::Null:
  llvm_unreachable("Non-deduced template arguments handled above")::llvm::llvm_unreachable_internal("Non-deduced template arguments handled above"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 238);

case TemplateArgument::Type:
  // If two template type arguments have the same type, they're compatible.
  if (Y.getKind() == TemplateArgument::Type &&
      Context.hasSameType(X.getAsType(), Y.getAsType()))
    return X;

  // If one of the two arguments was deduced from an array bound, the other
  // supersedes it.
  if (X.wasDeducedFromArrayBound() != Y.wasDeducedFromArrayBound())
    return X.wasDeducedFromArrayBound() ? Y : X;

  // The arguments are not compatible.
  return DeducedTemplateArgument();

case TemplateArgument::Integral:
  // If we deduced a constant in one case and either a dependent expression or
  // declaration in another case, keep the integral constant.
  // If both are integral constants with the same value, keep that value.
  if (Y.getKind() == TemplateArgument::Expression ||
      Y.getKind() == TemplateArgument::Declaration ||
      (Y.getKind() == TemplateArgument::Integral &&
       hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral())))
    return X.wasDeducedFromArrayBound() ? Y : X;

  // All other combinations are incompatible.
  return DeducedTemplateArgument();

case TemplateArgument::Template:
  if (Y.getKind() == TemplateArgument::Template &&
      Context.hasSameTemplateName(X.getAsTemplate(), Y.getAsTemplate()))
    return X;

  // All other combinations are incompatible.
  return DeducedTemplateArgument();

case TemplateArgument::TemplateExpansion:
  if (Y.getKind() == TemplateArgument::TemplateExpansion &&
      Context.hasSameTemplateName(X.getAsTemplateOrTemplatePattern(),
                                  Y.getAsTemplateOrTemplatePattern()))
    return X;

  // All other combinations are incompatible.
  return DeducedTemplateArgument();

case TemplateArgument::Expression: {
  if (Y.getKind() != TemplateArgument::Expression)
    return checkDeducedTemplateArguments(Context, Y, X);

  // Compare the expressions for equality
  llvm::FoldingSetNodeID ID1, ID2;
  X.getAsExpr()->Profile(ID1, Context, true);
  Y.getAsExpr()->Profile(ID2, Context, true);
  if (ID1 == ID2)
    return X.wasDeducedFromArrayBound() ? Y : X;

  // Differing dependent expressions are incompatible.
  return DeducedTemplateArgument();
}

case TemplateArgument::Declaration:
  assert(!X.wasDeducedFromArrayBound())((!X.wasDeducedFromArrayBound()) ? static_cast<void> (0
) : __assert_fail ("!X.wasDeducedFromArrayBound()", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 300, __PRETTY_FUNCTION__));

  // If we deduced a declaration and a dependent expression, keep the
  // declaration.
  if (Y.getKind() == TemplateArgument::Expression)
    return X;

  // If we deduced a declaration and an integral constant, keep the
  // integral constant and whichever type did not come from an array
  // bound.
  if (Y.getKind() == TemplateArgument::Integral) {
    if (Y.wasDeducedFromArrayBound())
      return TemplateArgument(Context, Y.getAsIntegral(),
                              X.getParamTypeForDecl());
    return Y;
  }

  // If we deduced two declarations, make sure that they refer to the
  // same declaration.
  if (Y.getKind() == TemplateArgument::Declaration &&
      isSameDeclaration(X.getAsDecl(), Y.getAsDecl()))
    return X;

  // All other combinations are incompatible.
  return DeducedTemplateArgument();

case TemplateArgument::NullPtr:
  // If we deduced a null pointer and a dependent expression, keep the
  // null pointer.
  if (Y.getKind() == TemplateArgument::Expression)
    return X;

  // If we deduced a null pointer and an integral constant, keep the
  // integral constant.
  if (Y.getKind() == TemplateArgument::Integral)
    return Y;

  // If we deduced two null pointers, they are the same.
  if (Y.getKind() == TemplateArgument::NullPtr)
    return X;

  // All other combinations are incompatible.
  return DeducedTemplateArgument();

case TemplateArgument::Pack: {
  if (Y.getKind() != TemplateArgument::Pack ||
      X.pack_size() != Y.pack_size())
    return DeducedTemplateArgument();

  llvm::SmallVector<TemplateArgument, 8> NewPack;
  for (TemplateArgument::pack_iterator XA = X.pack_begin(),
                                    XAEnd = X.pack_end(),
                                       YA = Y.pack_begin();
       XA != XAEnd; ++XA, ++YA) {
    TemplateArgument Merged = checkDeducedTemplateArguments(
        Context, DeducedTemplateArgument(*XA, X.wasDeducedFromArrayBound()),
        DeducedTemplateArgument(*YA, Y.wasDeducedFromArrayBound()));
    if (Merged.isNull())
      return DeducedTemplateArgument();
    NewPack.push_back(Merged);
  }

  return DeducedTemplateArgument(
      TemplateArgument::CreatePackCopy(Context, NewPack),
      X.wasDeducedFromArrayBound() && Y.wasDeducedFromArrayBound());
}
}

llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 368);
369}

371/// Deduce the value of the given non-type template parameter
372/// as the given deduced template argument. All non-type template parameter
373/// deduction is funneled through here.
374static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
  Sema &S, TemplateParameterList *TemplateParams,
  NonTypeTemplateParmDecl *NTTP, const DeducedTemplateArgument &NewDeduced,
  QualType ValueType, TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
assert(NTTP->getDepth() == Info.getDeducedDepth() &&((NTTP->getDepth() == Info.getDeducedDepth() && "deducing non-type template argument with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"deducing non-type template argument with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 380, __PRETTY_FUNCTION__))
       "deducing non-type template argument with wrong depth")((NTTP->getDepth() == Info.getDeducedDepth() && "deducing non-type template argument with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"deducing non-type template argument with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 380, __PRETTY_FUNCTION__));

DeducedTemplateArgument Result = checkDeducedTemplateArguments(
    S.Context, Deduced[NTTP->getIndex()], NewDeduced);
if (Result.isNull()) {
  Info.Param = NTTP;
  Info.FirstArg = Deduced[NTTP->getIndex()];
  Info.SecondArg = NewDeduced;
  return Sema::TDK_Inconsistent;
}

Deduced[NTTP->getIndex()] = Result;
if (!S.getLangOpts().CPlusPlus17)
  return Sema::TDK_Success;

if (NTTP->isExpandedParameterPack())
  // FIXME: We may still need to deduce parts of the type here! But we
  // don't have any way to find which slice of the type to use, and the
  // type stored on the NTTP itself is nonsense. Perhaps the type of an
  // expanded NTTP should be a pack expansion type?
  return Sema::TDK_Success;

// Get the type of the parameter for deduction. If it's a (dependent) array
// or function type, we will not have decayed it yet, so do that now.
QualType ParamType = S.Context.getAdjustedParameterType(NTTP->getType());
if (auto *Expansion = dyn_cast<PackExpansionType>(ParamType))
  ParamType = Expansion->getPattern();

// FIXME: It's not clear how deduction of a parameter of reference
// type from an argument (of non-reference type) should be performed.
// For now, we just remove reference types from both sides and let
// the final check for matching types sort out the mess.
return DeduceTemplateArgumentsByTypeMatch(
    S, TemplateParams, ParamType.getNonReferenceType(),
    ValueType.getNonReferenceType(), Info, Deduced, TDF_SkipNonDependent,
    /*PartialOrdering=*/false,
    /*ArrayBound=*/NewDeduced.wasDeducedFromArrayBound());
417}

419/// Deduce the value of the given non-type template parameter
420/// from the given integral constant.
421static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
  Sema &S, TemplateParameterList *TemplateParams,
  NonTypeTemplateParmDecl *NTTP, const llvm::APSInt &Value,
  QualType ValueType, bool DeducedFromArrayBound, TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
return DeduceNonTypeTemplateArgument(
    S, TemplateParams, NTTP,
    DeducedTemplateArgument(S.Context, Value, ValueType,
                            DeducedFromArrayBound),
    ValueType, Info, Deduced);
431}

433/// Deduce the value of the given non-type template parameter
434/// from the given null pointer template argument type.
435static Sema::TemplateDeductionResult DeduceNullPtrTemplateArgument(
  Sema &S, TemplateParameterList *TemplateParams,
  NonTypeTemplateParmDecl *NTTP, QualType NullPtrType,
  TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
Expr *Value =
    S.ImpCastExprToType(new (S.Context) CXXNullPtrLiteralExpr(
                            S.Context.NullPtrTy, NTTP->getLocation()),
                        NullPtrType, CK_NullToPointer)
        .get();
return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                     DeducedTemplateArgument(Value),
                                     Value->getType(), Info, Deduced);
448}

450/// Deduce the value of the given non-type template parameter
451/// from the given type- or value-dependent expression.
452///
453/// \returns true if deduction succeeded, false otherwise.
454static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
  Sema &S, TemplateParameterList *TemplateParams,
  NonTypeTemplateParmDecl *NTTP, Expr *Value, TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                     DeducedTemplateArgument(Value),
                                     Value->getType(), Info, Deduced);
461}

463/// Deduce the value of the given non-type template parameter
464/// from the given declaration.
465///
466/// \returns true if deduction succeeded, false otherwise.
467static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
  Sema &S, TemplateParameterList *TemplateParams,
  NonTypeTemplateParmDecl *NTTP, ValueDecl *D, QualType T,
  TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
D = D ? cast<ValueDecl>(D->getCanonicalDecl()) : nullptr;
TemplateArgument New(D, T);
return DeduceNonTypeTemplateArgument(
    S, TemplateParams, NTTP, DeducedTemplateArgument(New), T, Info, Deduced);
476}

478static Sema::TemplateDeductionResult
479DeduceTemplateArguments(Sema &S,
                      TemplateParameterList *TemplateParams,
                      TemplateName Param,
                      TemplateName Arg,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
TemplateDecl *ParamDecl = Param.getAsTemplateDecl();
if (!ParamDecl) {
  // The parameter type is dependent and is not a template template parameter,
  // so there is nothing that we can deduce.
  return Sema::TDK_Success;
}

if (TemplateTemplateParmDecl *TempParam
      = dyn_cast<TemplateTemplateParmDecl>(ParamDecl)) {
  // If we're not deducing at this depth, there's nothing to deduce.
  if (TempParam->getDepth() != Info.getDeducedDepth())
    return Sema::TDK_Success;

  DeducedTemplateArgument NewDeduced(S.Context.getCanonicalTemplateName(Arg));
  DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
                                               Deduced[TempParam->getIndex()],
                                                                 NewDeduced);
  if (Result.isNull()) {
    Info.Param = TempParam;
    Info.FirstArg = Deduced[TempParam->getIndex()];
    Info.SecondArg = NewDeduced;
    return Sema::TDK_Inconsistent;
  }

  Deduced[TempParam->getIndex()] = Result;
  return Sema::TDK_Success;
}

// Verify that the two template names are equivalent.
if (S.Context.hasSameTemplateName(Param, Arg))
  return Sema::TDK_Success;

// Mismatch of non-dependent template parameter to argument.
Info.FirstArg = TemplateArgument(Param);
Info.SecondArg = TemplateArgument(Arg);
return Sema::TDK_NonDeducedMismatch;
521}

523/// Deduce the template arguments by comparing the template parameter
524/// type (which is a template-id) with the template argument type.
525///
526/// \param S the Sema
527///
528/// \param TemplateParams the template parameters that we are deducing
529///
530/// \param Param the parameter type
531///
532/// \param Arg the argument type
533///
534/// \param Info information about the template argument deduction itself
535///
536/// \param Deduced the deduced template arguments
537///
538/// \returns the result of template argument deduction so far. Note that a
539/// "success" result means that template argument deduction has not yet failed,
540/// but it may still fail, later, for other reasons.
541static Sema::TemplateDeductionResult
542DeduceTemplateArguments(Sema &S,
                      TemplateParameterList *TemplateParams,
                      const TemplateSpecializationType *Param,
                      QualType Arg,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
assert(Arg.isCanonical() && "Argument type must be canonical")((Arg.isCanonical() && "Argument type must be canonical"
) ? static_cast<void> (0) : __assert_fail ("Arg.isCanonical() && \"Argument type must be canonical\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 548, __PRETTY_FUNCTION__));

// Treat an injected-class-name as its underlying template-id.
if (auto *Injected = dyn_cast<InjectedClassNameType>(Arg))
  Arg = Injected->getInjectedSpecializationType();

// Check whether the template argument is a dependent template-id.
if (const TemplateSpecializationType *SpecArg
      = dyn_cast<TemplateSpecializationType>(Arg)) {
  // Perform template argument deduction for the template name.
  if (Sema::TemplateDeductionResult Result
        = DeduceTemplateArguments(S, TemplateParams,
                                  Param->getTemplateName(),
                                  SpecArg->getTemplateName(),
                                  Info, Deduced))
    return Result;


  // Perform template argument deduction on each template
  // argument. Ignore any missing/extra arguments, since they could be
  // filled in by default arguments.
  return DeduceTemplateArguments(S, TemplateParams,
                                 Param->template_arguments(),
                                 SpecArg->template_arguments(), Info, Deduced,
                                 /*NumberOfArgumentsMustMatch=*/false);
}

// If the argument type is a class template specialization, we
// perform template argument deduction using its template
// arguments.
const RecordType *RecordArg = dyn_cast<RecordType>(Arg);
if (!RecordArg) {
  Info.FirstArg = TemplateArgument(QualType(Param, 0));
  Info.SecondArg = TemplateArgument(Arg);
  return Sema::TDK_NonDeducedMismatch;
}

ClassTemplateSpecializationDecl *SpecArg
  = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl());
if (!SpecArg) {
  Info.FirstArg = TemplateArgument(QualType(Param, 0));
  Info.SecondArg = TemplateArgument(Arg);
  return Sema::TDK_NonDeducedMismatch;
}

// Perform template argument deduction for the template name.
if (Sema::TemplateDeductionResult Result
      = DeduceTemplateArguments(S,
                                TemplateParams,
                                Param->getTemplateName(),
                             TemplateName(SpecArg->getSpecializedTemplate()),
                                Info, Deduced))
  return Result;

// Perform template argument deduction for the template arguments.
return DeduceTemplateArguments(S, TemplateParams, Param->template_arguments(),
                               SpecArg->getTemplateArgs().asArray(), Info,
                               Deduced, /*NumberOfArgumentsMustMatch=*/true);
606}

608/// Determines whether the given type is an opaque type that
609/// might be more qualified when instantiated.
610static bool IsPossiblyOpaquelyQualifiedType(QualType T) {
switch (T->getTypeClass()) {
case Type::TypeOfExpr:
case Type::TypeOf:
case Type::DependentName:
case Type::Decltype:
case Type::UnresolvedUsing:
case Type::TemplateTypeParm:
  return true;

case Type::ConstantArray:
case Type::IncompleteArray:
case Type::VariableArray:
case Type::DependentSizedArray:
  return IsPossiblyOpaquelyQualifiedType(
                                    cast<ArrayType>(T)->getElementType());

default:
  return false;
}
630}

632/// Helper function to build a TemplateParameter when we don't
633/// know its type statically.
634static TemplateParameter makeTemplateParameter(Decl *D) {
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D))
  return TemplateParameter(TTP);
if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D))
  return TemplateParameter(NTTP);

return TemplateParameter(cast<TemplateTemplateParmDecl>(D));
641}

643/// If \p Param is an expanded parameter pack, get the number of expansions.
644static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param))
  if (NTTP->isExpandedParameterPack())
    return NTTP->getNumExpansionTypes();

if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(Param))
  if (TTP->isExpandedParameterPack())
    return TTP->getNumExpansionTemplateParameters();

return None;
654}

656/// A pack that we're currently deducing.
657struct clang::DeducedPack {
// The index of the pack.
unsigned Index;

// The old value of the pack before we started deducing it.
DeducedTemplateArgument Saved;

// A deferred value of this pack from an inner deduction, that couldn't be
// deduced because this deduction hadn't happened yet.
DeducedTemplateArgument DeferredDeduction;

// The new value of the pack.
SmallVector<DeducedTemplateArgument, 4> New;

// The outer deduction for this pack, if any.
DeducedPack *Outer = nullptr;

DeducedPack(unsigned Index) : Index(Index) {}
675};

677namespace {

679/// A scope in which we're performing pack deduction.
680class PackDeductionScope {
681public:
/// Prepare to deduce the packs named within Pattern.
PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
                   SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                   TemplateDeductionInfo &Info, TemplateArgument Pattern)
    : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
  unsigned NumNamedPacks = addPacks(Pattern);
  finishConstruction(NumNamedPacks);
}

/// Prepare to directly deduce arguments of the parameter with index \p Index.
PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
                   SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                   TemplateDeductionInfo &Info, unsigned Index)
    : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
  addPack(Index);
  finishConstruction(1);
}

700private:
void addPack(unsigned Index) {
  // Save the deduced template argument for the parameter pack expanded
  // by this pack expansion, then clear out the deduction.
  DeducedPack Pack(Index);
  Pack.Saved = Deduced[Index];
  Deduced[Index] = TemplateArgument();

  // FIXME: What if we encounter multiple packs with different numbers of
  // pre-expanded expansions? (This should already have been diagnosed
  // during substitution.)
  if (Optional<unsigned> ExpandedPackExpansions =
          getExpandedPackSize(TemplateParams->getParam(Index)))
    FixedNumExpansions = ExpandedPackExpansions;

  Packs.push_back(Pack);
}

unsigned addPacks(TemplateArgument Pattern) {
  // Compute the set of template parameter indices that correspond to
  // parameter packs expanded by the pack expansion.
  llvm::SmallBitVector SawIndices(TemplateParams->size());

  auto AddPack = [&](unsigned Index) {
    if (SawIndices[Index])
      return;
    SawIndices[Index] = true;
    addPack(Index);
  };

  // First look for unexpanded packs in the pattern.
  SmallVector<UnexpandedParameterPack, 2> Unexpanded;
  S.collectUnexpandedParameterPacks(Pattern, Unexpanded);
  for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
    unsigned Depth, Index;
    std::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]);
    if (Depth == Info.getDeducedDepth())
      AddPack(Index);
  }
  assert(!Packs.empty() && "Pack expansion without unexpanded packs?")((!Packs.empty() && "Pack expansion without unexpanded packs?"
) ? static_cast<void> (0) : __assert_fail ("!Packs.empty() && \"Pack expansion without unexpanded packs?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 739, __PRETTY_FUNCTION__));

  unsigned NumNamedPacks = Packs.size();

  // We can also have deduced template parameters that do not actually
  // appear in the pattern, but can be deduced by it (the type of a non-type
  // template parameter pack, in particular). These won't have prevented us
  // from partially expanding the pack.
  llvm::SmallBitVector Used(TemplateParams->size());
  MarkUsedTemplateParameters(S.Context, Pattern, /*OnlyDeduced*/true,
                             Info.getDeducedDepth(), Used);
  for (int Index = Used.find_first(); Index != -1;
       Index = Used.find_next(Index))
    if (TemplateParams->getParam(Index)->isParameterPack())
      AddPack(Index);

  return NumNamedPacks;
}

void finishConstruction(unsigned NumNamedPacks) {
  // Dig out the partially-substituted pack, if there is one.
  const TemplateArgument *PartialPackArgs = nullptr;
  unsigned NumPartialPackArgs = 0;
  std::pair<unsigned, unsigned> PartialPackDepthIndex(-1u, -1u);
  if (auto *Scope = S.CurrentInstantiationScope)
    if (auto *Partial = Scope->getPartiallySubstitutedPack(
            &PartialPackArgs, &NumPartialPackArgs))
      PartialPackDepthIndex = getDepthAndIndex(Partial);

  // This pack expansion will have been partially or fully expanded if
  // it only names explicitly-specified parameter packs (including the
  // partially-substituted one, if any).
  bool IsExpanded = true;
  for (unsigned I = 0; I != NumNamedPacks; ++I) {
    if (Packs[I].Index >= Info.getNumExplicitArgs()) {
      IsExpanded = false;
      IsPartiallyExpanded = false;
      break;
    }
    if (PartialPackDepthIndex ==
          std::make_pair(Info.getDeducedDepth(), Packs[I].Index)) {
      IsPartiallyExpanded = true;
    }
  }

  // Skip over the pack elements that were expanded into separate arguments.
  // If we partially expanded, this is the number of partial arguments.
  if (IsPartiallyExpanded)
    PackElements += NumPartialPackArgs;
  else if (IsExpanded)
    PackElements += *FixedNumExpansions;

  for (auto &Pack : Packs) {
    if (Info.PendingDeducedPacks.size() > Pack.Index)
      Pack.Outer = Info.PendingDeducedPacks[Pack.Index];
    else
      Info.PendingDeducedPacks.resize(Pack.Index + 1);
    Info.PendingDeducedPacks[Pack.Index] = &Pack;

    if (PartialPackDepthIndex ==
          std::make_pair(Info.getDeducedDepth(), Pack.Index)) {
      Pack.New.append(PartialPackArgs, PartialPackArgs + NumPartialPackArgs);
      // We pre-populate the deduced value of the partially-substituted
      // pack with the specified value. This is not entirely correct: the
      // value is supposed to have been substituted, not deduced, but the
      // cases where this is observable require an exact type match anyway.
      //
      // FIXME: If we could represent a "depth i, index j, pack elem k"
      // parameter, we could substitute the partially-substituted pack
      // everywhere and avoid this.
      if (!IsPartiallyExpanded)
        Deduced[Pack.Index] = Pack.New[PackElements];
    }
  }
}

815public:
~PackDeductionScope() {
  for (auto &Pack : Packs)
    Info.PendingDeducedPacks[Pack.Index] = Pack.Outer;
}

/// Determine whether this pack has already been partially expanded into a
/// sequence of (prior) function parameters / template arguments.
bool isPartiallyExpanded() { return IsPartiallyExpanded; }

/// Determine whether this pack expansion scope has a known, fixed arity.
/// This happens if it involves a pack from an outer template that has
/// (notionally) already been expanded.
bool hasFixedArity() { return FixedNumExpansions.hasValue(); }

/// Determine whether the next element of the argument is still part of this
/// pack. This is the case unless the pack is already expanded to a fixed
/// length.
bool hasNextElement() {
  return !FixedNumExpansions || *FixedNumExpansions > PackElements;
}

/// Move to deducing the next element in each pack that is being deduced.
void nextPackElement() {
  // Capture the deduced template arguments for each parameter pack expanded
  // by this pack expansion, add them to the list of arguments we've deduced
  // for that pack, then clear out the deduced argument.
  for (auto &Pack : Packs) {
    DeducedTemplateArgument &DeducedArg = Deduced[Pack.Index];
    if (!Pack.New.empty() || !DeducedArg.isNull()) {
      while (Pack.New.size() < PackElements)
        Pack.New.push_back(DeducedTemplateArgument());
      if (Pack.New.size() == PackElements)
        Pack.New.push_back(DeducedArg);
      else
        Pack.New[PackElements] = DeducedArg;
      DeducedArg = Pack.New.size() > PackElements + 1
                       ? Pack.New[PackElements + 1]
                       : DeducedTemplateArgument();
    }
  }
  ++PackElements;
}

/// Finish template argument deduction for a set of argument packs,
/// producing the argument packs and checking for consistency with prior
/// deductions.
Sema::TemplateDeductionResult
finish(bool TreatNoDeductionsAsNonDeduced = true) {
  // Build argument packs for each of the parameter packs expanded by this
  // pack expansion.
  for (auto &Pack : Packs) {
    // Put back the old value for this pack.
    Deduced[Pack.Index] = Pack.Saved;

    // If we are deducing the size of this pack even if we didn't deduce any
    // values for it, then make sure we build a pack of the right size.
    // FIXME: Should we always deduce the size, even if the pack appears in
    // a non-deduced context?
    if (!TreatNoDeductionsAsNonDeduced)
      Pack.New.resize(PackElements);

    // Build or find a new value for this pack.
    DeducedTemplateArgument NewPack;
    if (PackElements && Pack.New.empty()) {
      if (Pack.DeferredDeduction.isNull()) {
        // We were not able to deduce anything for this parameter pack
        // (because it only appeared in non-deduced contexts), so just
        // restore the saved argument pack.
        continue;
      }

      NewPack = Pack.DeferredDeduction;
      Pack.DeferredDeduction = TemplateArgument();
    } else if (Pack.New.empty()) {
      // If we deduced an empty argument pack, create it now.
      NewPack = DeducedTemplateArgument(TemplateArgument::getEmptyPack());
    } else {
      TemplateArgument *ArgumentPack =
          new (S.Context) TemplateArgument[Pack.New.size()];
      std::copy(Pack.New.begin(), Pack.New.end(), ArgumentPack);
      NewPack = DeducedTemplateArgument(
          TemplateArgument(llvm::makeArrayRef(ArgumentPack, Pack.New.size())),
          // FIXME: This is wrong, it's possible that some pack elements are
          // deduced from an array bound and others are not:
          //   template<typename ...T, T ...V> void g(const T (&...p)[V]);
          //   g({1, 2, 3}, {{}, {}});
          // ... should deduce T = {int, size_t (from array bound)}.
          Pack.New[0].wasDeducedFromArrayBound());
    }

    // Pick where we're going to put the merged pack.
    DeducedTemplateArgument *Loc;
    if (Pack.Outer) {
      if (Pack.Outer->DeferredDeduction.isNull()) {
        // Defer checking this pack until we have a complete pack to compare
        // it against.
        Pack.Outer->DeferredDeduction = NewPack;
        continue;
      }
      Loc = &Pack.Outer->DeferredDeduction;
    } else {
      Loc = &Deduced[Pack.Index];
    }

    // Check the new pack matches any previous value.
    DeducedTemplateArgument OldPack = *Loc;
    DeducedTemplateArgument Result =
        checkDeducedTemplateArguments(S.Context, OldPack, NewPack);

    // If we deferred a deduction of this pack, check that one now too.
    if (!Result.isNull() && !Pack.DeferredDeduction.isNull()) {
      OldPack = Result;
      NewPack = Pack.DeferredDeduction;
      Result = checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
    }

    NamedDecl *Param = TemplateParams->getParam(Pack.Index);
    if (Result.isNull()) {
      Info.Param = makeTemplateParameter(Param);
      Info.FirstArg = OldPack;
      Info.SecondArg = NewPack;
      return Sema::TDK_Inconsistent;
    }

    // If we have a pre-expanded pack and we didn't deduce enough elements
    // for it, fail deduction.
    if (Optional<unsigned> Expansions = getExpandedPackSize(Param)) {
      if (*Expansions != PackElements) {
        Info.Param = makeTemplateParameter(Param);
        Info.FirstArg = Result;
        return Sema::TDK_IncompletePack;
      }
    }

    *Loc = Result;
  }

  return Sema::TDK_Success;
}

956private:
Sema &S;
TemplateParameterList *TemplateParams;
SmallVectorImpl<DeducedTemplateArgument> &Deduced;
TemplateDeductionInfo &Info;
unsigned PackElements = 0;
bool IsPartiallyExpanded = false;
/// The number of expansions, if we have a fully-expanded pack in this scope.
Optional<unsigned> FixedNumExpansions;

SmallVector<DeducedPack, 2> Packs;
967};

969} // namespace

971/// Deduce the template arguments by comparing the list of parameter
972/// types to the list of argument types, as in the parameter-type-lists of
973/// function types (C++ [temp.deduct.type]p10).
974///
975/// \param S The semantic analysis object within which we are deducing
976///
977/// \param TemplateParams The template parameters that we are deducing
978///
979/// \param Params The list of parameter types
980///
981/// \param NumParams The number of types in \c Params
982///
983/// \param Args The list of argument types
984///
985/// \param NumArgs The number of types in \c Args
986///
987/// \param Info information about the template argument deduction itself
988///
989/// \param Deduced the deduced template arguments
990///
991/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
992/// how template argument deduction is performed.
993///
994/// \param PartialOrdering If true, we are performing template argument
995/// deduction for during partial ordering for a call
996/// (C++0x [temp.deduct.partial]).
997///
998/// \returns the result of template argument deduction so far. Note that a
999/// "success" result means that template argument deduction has not yet failed,
1000/// but it may still fail, later, for other reasons.
1001static Sema::TemplateDeductionResult
1002DeduceTemplateArguments(Sema &S,
                      TemplateParameterList *TemplateParams,
                      const QualType *Params, unsigned NumParams,
                      const QualType *Args, unsigned NumArgs,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                      unsigned TDF,
                      bool PartialOrdering = false) {
// C++0x [temp.deduct.type]p10:
//   Similarly, if P has a form that contains (T), then each parameter type
//   Pi of the respective parameter-type- list of P is compared with the
//   corresponding parameter type Ai of the corresponding parameter-type-list
//   of A. [...]
unsigned ArgIdx = 0, ParamIdx = 0;
for (; ParamIdx != NumParams; ++ParamIdx) {
  // Check argument types.
  const PackExpansionType *Expansion
                              = dyn_cast<PackExpansionType>(Params[ParamIdx]);
  if (!Expansion) {
    // Simple case: compare the parameter and argument types at this point.

    // Make sure we have an argument.
    if (ArgIdx >= NumArgs)
      return Sema::TDK_MiscellaneousDeductionFailure;

    if (isa<PackExpansionType>(Args[ArgIdx])) {
      // C++0x [temp.deduct.type]p22:
      //   If the original function parameter associated with A is a function
      //   parameter pack and the function parameter associated with P is not
      //   a function parameter pack, then template argument deduction fails.
      return Sema::TDK_MiscellaneousDeductionFailure;
    }

    if (Sema::TemplateDeductionResult Result
          = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                               Params[ParamIdx], Args[ArgIdx],
                                               Info, Deduced, TDF,
                                               PartialOrdering))
      return Result;

    ++ArgIdx;
    continue;
  }

  // C++0x [temp.deduct.type]p10:
  //   If the parameter-declaration corresponding to Pi is a function
  //   parameter pack, then the type of its declarator- id is compared with
  //   each remaining parameter type in the parameter-type-list of A. Each
  //   comparison deduces template arguments for subsequent positions in the
  //   template parameter packs expanded by the function parameter pack.

  QualType Pattern = Expansion->getPattern();
  PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);

  // A pack scope with fixed arity is not really a pack any more, so is not
  // a non-deduced context.
  if (ParamIdx + 1 == NumParams || PackScope.hasFixedArity()) {
    for (; ArgIdx < NumArgs && PackScope.hasNextElement(); ++ArgIdx) {
      // Deduce template arguments from the pattern.
      if (Sema::TemplateDeductionResult Result
            = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, Pattern,
                                                 Args[ArgIdx], Info, Deduced,
                                                 TDF, PartialOrdering))
        return Result;

      PackScope.nextPackElement();
    }
  } else {
    // C++0x [temp.deduct.type]p5:
    //   The non-deduced contexts are:
    //     - A function parameter pack that does not occur at the end of the
    //       parameter-declaration-clause.
    //
    // FIXME: There is no wording to say what we should do in this case. We
    // choose to resolve this by applying the same rule that is applied for a
    // function call: that is, deduce all contained packs to their
    // explicitly-specified values (or to <> if there is no such value).
    //
    // This is seemingly-arbitrarily different from the case of a template-id
    // with a non-trailing pack-expansion in its arguments, which renders the
    // entire template-argument-list a non-deduced context.

    // If the parameter type contains an explicitly-specified pack that we
    // could not expand, skip the number of parameters notionally created
    // by the expansion.
    Optional<unsigned> NumExpansions = Expansion->getNumExpansions();
    if (NumExpansions && !PackScope.isPartiallyExpanded()) {
      for (unsigned I = 0; I != *NumExpansions && ArgIdx < NumArgs;
           ++I, ++ArgIdx)
        PackScope.nextPackElement();
    }
  }

  // Build argument packs for each of the parameter packs expanded by this
  // pack expansion.
  if (auto Result = PackScope.finish())
    return Result;
}

// Make sure we don't have any extra arguments.
if (ArgIdx < NumArgs)
  return Sema::TDK_MiscellaneousDeductionFailure;

return Sema::TDK_Success;
1106}

1108/// Determine whether the parameter has qualifiers that the argument
1109/// lacks. Put another way, determine whether there is no way to add
1110/// a deduced set of qualifiers to the ParamType that would result in
1111/// its qualifiers matching those of the ArgType.
1112static bool hasInconsistentOrSupersetQualifiersOf(QualType ParamType,
                                                QualType ArgType) {
Qualifiers ParamQs = ParamType.getQualifiers();
Qualifiers ArgQs = ArgType.getQualifiers();

if (ParamQs == ArgQs)
  return false;

// Mismatched (but not missing) Objective-C GC attributes.
if (ParamQs.getObjCGCAttr() != ArgQs.getObjCGCAttr() &&
    ParamQs.hasObjCGCAttr())
  return true;

// Mismatched (but not missing) address spaces.
if (ParamQs.getAddressSpace() != ArgQs.getAddressSpace() &&
    ParamQs.hasAddressSpace())
  return true;

// Mismatched (but not missing) Objective-C lifetime qualifiers.
if (ParamQs.getObjCLifetime() != ArgQs.getObjCLifetime() &&
    ParamQs.hasObjCLifetime())
  return true;

// CVR qualifiers inconsistent or a superset.
return (ParamQs.getCVRQualifiers() & ~ArgQs.getCVRQualifiers()) != 0;
1137}

1139/// Compare types for equality with respect to possibly compatible
1140/// function types (noreturn adjustment, implicit calling conventions). If any
1141/// of parameter and argument is not a function, just perform type comparison.
1142///
1143/// \param Param the template parameter type.
1144///
1145/// \param Arg the argument type.
1146bool Sema::isSameOrCompatibleFunctionType(CanQualType Param,
                                        CanQualType Arg) {
const FunctionType *ParamFunction = Param->getAs<FunctionType>(),
                   *ArgFunction   = Arg->getAs<FunctionType>();

// Just compare if not functions.
if (!ParamFunction || !ArgFunction)
  return Param == Arg;

// Noreturn and noexcept adjustment.
QualType AdjustedParam;
if (IsFunctionConversion(Param, Arg, AdjustedParam))
  return Arg == Context.getCanonicalType(AdjustedParam);

// FIXME: Compatible calling conventions.

return Param == Arg;
1163}

1165/// Get the index of the first template parameter that was originally from the
1166/// innermost template-parameter-list. This is 0 except when we concatenate
1167/// the template parameter lists of a class template and a constructor template
1168/// when forming an implicit deduction guide.
1169static unsigned getFirstInnerIndex(FunctionTemplateDecl *FTD) {
auto *Guide = dyn_cast<CXXDeductionGuideDecl>(FTD->getTemplatedDecl());
if (!Guide || !Guide->isImplicit())
  return 0;
return Guide->getDeducedTemplate()->getTemplateParameters()->size();
1174}

1176/// Determine whether a type denotes a forwarding reference.
1177static bool isForwardingReference(QualType Param, unsigned FirstInnerIndex) {
// C++1z [temp.deduct.call]p3:
//   A forwarding reference is an rvalue reference to a cv-unqualified
//   template parameter that does not represent a template parameter of a
//   class template.
if (auto *ParamRef = Param->getAs<RValueReferenceType>()) {
  if (ParamRef->getPointeeType().getQualifiers())
    return false;
  auto *TypeParm = ParamRef->getPointeeType()->getAs<TemplateTypeParmType>();
  return TypeParm && TypeParm->getIndex() >= FirstInnerIndex;
}
return false;
1189}

1191/// Deduce the template arguments by comparing the parameter type and
1192/// the argument type (C++ [temp.deduct.type]).
1193///
1194/// \param S the semantic analysis object within which we are deducing
1195///
1196/// \param TemplateParams the template parameters that we are deducing
1197///
1198/// \param ParamIn the parameter type
1199///
1200/// \param ArgIn the argument type
1201///
1202/// \param Info information about the template argument deduction itself
1203///
1204/// \param Deduced the deduced template arguments
1205///
1206/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
1207/// how template argument deduction is performed.
1208///
1209/// \param PartialOrdering Whether we're performing template argument deduction
1210/// in the context of partial ordering (C++0x [temp.deduct.partial]).
1211///
1212/// \returns the result of template argument deduction so far. Note that a
1213/// "success" result means that template argument deduction has not yet failed,
1214/// but it may still fail, later, for other reasons.
1215static Sema::TemplateDeductionResult
1216DeduceTemplateArgumentsByTypeMatch(Sema &S,
                                 TemplateParameterList *TemplateParams,
                                 QualType ParamIn, QualType ArgIn,
                                 TemplateDeductionInfo &Info,
                          SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                                 unsigned TDF,
                                 bool PartialOrdering,
                                 bool DeducedFromArrayBound) {
// We only want to look at the canonical types, since typedefs and
// sugar are not part of template argument deduction.
QualType Param = S.Context.getCanonicalType(ParamIn);
QualType Arg = S.Context.getCanonicalType(ArgIn);

// If the argument type is a pack expansion, look at its pattern.
// This isn't explicitly called out
if (const PackExpansionType *ArgExpansion
                                          = dyn_cast<PackExpansionType>(Arg))
  Arg = ArgExpansion->getPattern();

if (PartialOrdering) {
  // C++11 [temp.deduct.partial]p5:
  //   Before the partial ordering is done, certain transformations are
  //   performed on the types used for partial ordering:
  //     - If P is a reference type, P is replaced by the type referred to.
  const ReferenceType *ParamRef = Param->getAs<ReferenceType>();
  if (ParamRef)
    Param = ParamRef->getPointeeType();

  //     - If A is a reference type, A is replaced by the type referred to.
  const ReferenceType *ArgRef = Arg->getAs<ReferenceType>();
  if (ArgRef)
    Arg = ArgRef->getPointeeType();

  if (ParamRef && ArgRef && S.Context.hasSameUnqualifiedType(Param, Arg)) {
    // C++11 [temp.deduct.partial]p9:
    //   If, for a given type, deduction succeeds in both directions (i.e.,
    //   the types are identical after the transformations above) and both
    //   P and A were reference types [...]:
    //     - if [one type] was an lvalue reference and [the other type] was
    //       not, [the other type] is not considered to be at least as
    //       specialized as [the first type]
    //     - if [one type] is more cv-qualified than [the other type],
    //       [the other type] is not considered to be at least as specialized
    //       as [the first type]
    // Objective-C ARC adds:
    //     - [one type] has non-trivial lifetime, [the other type] has
    //       __unsafe_unretained lifetime, and the types are otherwise
    //       identical
    //
    // A is "considered to be at least as specialized" as P iff deduction
    // succeeds, so we model this as a deduction failure. Note that
    // [the first type] is P and [the other type] is A here; the standard
    // gets this backwards.
    Qualifiers ParamQuals = Param.getQualifiers();
    Qualifiers ArgQuals = Arg.getQualifiers();
    if ((ParamRef->isLValueReferenceType() &&
         !ArgRef->isLValueReferenceType()) ||
        ParamQuals.isStrictSupersetOf(ArgQuals) ||
        (ParamQuals.hasNonTrivialObjCLifetime() &&
         ArgQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
         ParamQuals.withoutObjCLifetime() ==
             ArgQuals.withoutObjCLifetime())) {
      Info.FirstArg = TemplateArgument(ParamIn);
      Info.SecondArg = TemplateArgument(ArgIn);
      return Sema::TDK_NonDeducedMismatch;
    }
  }

  // C++11 [temp.deduct.partial]p7:
  //   Remove any top-level cv-qualifiers:
  //     - If P is a cv-qualified type, P is replaced by the cv-unqualified
  //       version of P.
  Param = Param.getUnqualifiedType();
  //     - If A is a cv-qualified type, A is replaced by the cv-unqualified
  //       version of A.
  Arg = Arg.getUnqualifiedType();
} else {
  // C++0x [temp.deduct.call]p4 bullet 1:
  //   - If the original P is a reference type, the deduced A (i.e., the type
  //     referred to by the reference) can be more cv-qualified than the
  //     transformed A.
  if (TDF & TDF_ParamWithReferenceType) {
    Qualifiers Quals;
    QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals);
    Quals.setCVRQualifiers(Quals.getCVRQualifiers() &
                           Arg.getCVRQualifiers());
    Param = S.Context.getQualifiedType(UnqualParam, Quals);
  }

  if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) {
    // C++0x [temp.deduct.type]p10:
    //   If P and A are function types that originated from deduction when
    //   taking the address of a function template (14.8.2.2) or when deducing
    //   template arguments from a function declaration (14.8.2.6) and Pi and
    //   Ai are parameters of the top-level parameter-type-list of P and A,
    //   respectively, Pi is adjusted if it is a forwarding reference and Ai
    //   is an lvalue reference, in
    //   which case the type of Pi is changed to be the template parameter
    //   type (i.e., T&& is changed to simply T). [ Note: As a result, when
    //   Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be
    //   deduced as X&. - end note ]
    TDF &= ~TDF_TopLevelParameterTypeList;
    if (isForwardingReference(Param, 0) && Arg->isLValueReferenceType())
      Param = Param->getPointeeType();
  }
}

// C++ [temp.deduct.type]p9:
//   A template type argument T, a template template argument TT or a
//   template non-type argument i can be deduced if P and A have one of
//   the following forms:
//
//     T
//     cv-list T
if (const TemplateTypeParmType *TemplateTypeParm
      = Param->getAs<TemplateTypeParmType>()) {
  // Just skip any attempts to deduce from a placeholder type or a parameter
  // at a different depth.
  if (Arg->isPlaceholderType() ||
      Info.getDeducedDepth() != TemplateTypeParm->getDepth())
    return Sema::TDK_Success;

  unsigned Index = TemplateTypeParm->getIndex();
  bool RecanonicalizeArg = false;

  // If the argument type is an array type, move the qualifiers up to the
  // top level, so they can be matched with the qualifiers on the parameter.
  if (isa<ArrayType>(Arg)) {
    Qualifiers Quals;
    Arg = S.Context.getUnqualifiedArrayType(Arg, Quals);
    if (Quals) {
      Arg = S.Context.getQualifiedType(Arg, Quals);
      RecanonicalizeArg = true;
    }
  }

  // The argument type can not be less qualified than the parameter
  // type.
  if (!(TDF & TDF_IgnoreQualifiers) &&
      hasInconsistentOrSupersetQualifiersOf(Param, Arg)) {
    Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
    Info.FirstArg = TemplateArgument(Param);
    Info.SecondArg = TemplateArgument(Arg);
    return Sema::TDK_Underqualified;
  }

  // Do not match a function type with a cv-qualified type.
  // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1584
  if (Arg->isFunctionType() && Param.hasQualifiers()) {
    return Sema::TDK_NonDeducedMismatch;
  }

  assert(TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&((TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&
 "saw template type parameter with wrong depth") ? static_cast
<void> (0) : __assert_fail ("TemplateTypeParm->getDepth() == Info.getDeducedDepth() && \"saw template type parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1369, __PRETTY_FUNCTION__))
         "saw template type parameter with wrong depth")((TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&
 "saw template type parameter with wrong depth") ? static_cast
<void> (0) : __assert_fail ("TemplateTypeParm->getDepth() == Info.getDeducedDepth() && \"saw template type parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1369, __PRETTY_FUNCTION__));
  assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function")((Arg != S.Context.OverloadTy && "Unresolved overloaded function"
) ? static_cast<void> (0) : __assert_fail ("Arg != S.Context.OverloadTy && \"Unresolved overloaded function\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1370, __PRETTY_FUNCTION__));
  QualType DeducedType = Arg;

  // Remove any qualifiers on the parameter from the deduced type.
  // We checked the qualifiers for consistency above.
  Qualifiers DeducedQs = DeducedType.getQualifiers();
  Qualifiers ParamQs = Param.getQualifiers();
  DeducedQs.removeCVRQualifiers(ParamQs.getCVRQualifiers());
  if (ParamQs.hasObjCGCAttr())
    DeducedQs.removeObjCGCAttr();
  if (ParamQs.hasAddressSpace())
    DeducedQs.removeAddressSpace();
  if (ParamQs.hasObjCLifetime())
    DeducedQs.removeObjCLifetime();

  // Objective-C ARC:
  //   If template deduction would produce a lifetime qualifier on a type
  //   that is not a lifetime type, template argument deduction fails.
  if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() &&
      !DeducedType->isDependentType()) {
    Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
    Info.FirstArg = TemplateArgument(Param);
    Info.SecondArg = TemplateArgument(Arg);
    return Sema::TDK_Underqualified;
  }

  // Objective-C ARC:
  //   If template deduction would produce an argument type with lifetime type
  //   but no lifetime qualifier, the __strong lifetime qualifier is inferred.
  if (S.getLangOpts().ObjCAutoRefCount &&
      DeducedType->isObjCLifetimeType() &&
      !DeducedQs.hasObjCLifetime())
    DeducedQs.setObjCLifetime(Qualifiers::OCL_Strong);

  DeducedType = S.Context.getQualifiedType(DeducedType.getUnqualifiedType(),
                                           DeducedQs);

  if (RecanonicalizeArg)
    DeducedType = S.Context.getCanonicalType(DeducedType);

  DeducedTemplateArgument NewDeduced(DeducedType, DeducedFromArrayBound);
  DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
                                                               Deduced[Index],
                                                                 NewDeduced);
  if (Result.isNull()) {
    Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
    Info.FirstArg = Deduced[Index];
    Info.SecondArg = NewDeduced;
    return Sema::TDK_Inconsistent;
  }

  Deduced[Index] = Result;
  return Sema::TDK_Success;
}

// Set up the template argument deduction information for a failure.
Info.FirstArg = TemplateArgument(ParamIn);
Info.SecondArg = TemplateArgument(ArgIn);

// If the parameter is an already-substituted template parameter
// pack, do nothing: we don't know which of its arguments to look
// at, so we have to wait until all of the parameter packs in this
// expansion have arguments.
if (isa<SubstTemplateTypeParmPackType>(Param))
  return Sema::TDK_Success;

// Check the cv-qualifiers on the parameter and argument types.
CanQualType CanParam = S.Context.getCanonicalType(Param);
CanQualType CanArg = S.Context.getCanonicalType(Arg);
if (!(TDF & TDF_IgnoreQualifiers)) {
  if (TDF & TDF_ParamWithReferenceType) {
    if (hasInconsistentOrSupersetQualifiersOf(Param, Arg))
      return Sema::TDK_NonDeducedMismatch;
  } else if (TDF & TDF_ArgWithReferenceType) {
    // C++ [temp.deduct.conv]p4:
    //   If the original A is a reference type, A can be more cv-qualified
    //   than the deduced A
    if (!Arg.getQualifiers().compatiblyIncludes(Param.getQualifiers()))
      return Sema::TDK_NonDeducedMismatch;

    // Strip out all extra qualifiers from the argument to figure out the
    // type we're converting to, prior to the qualification conversion.
    Qualifiers Quals;
    Arg = S.Context.getUnqualifiedArrayType(Arg, Quals);
    Arg = S.Context.getQualifiedType(Arg, Param.getQualifiers());
  } else if (!IsPossiblyOpaquelyQualifiedType(Param)) {
    if (Param.getCVRQualifiers() != Arg.getCVRQualifiers())
      return Sema::TDK_NonDeducedMismatch;
  }

  // If the parameter type is not dependent, there is nothing to deduce.
  if (!Param->isDependentType()) {
    if (!(TDF & TDF_SkipNonDependent)) {
      bool NonDeduced =
          (TDF & TDF_AllowCompatibleFunctionType)
              ? !S.isSameOrCompatibleFunctionType(CanParam, CanArg)
              : Param != Arg;
      if (NonDeduced) {
        return Sema::TDK_NonDeducedMismatch;
      }
    }
    return Sema::TDK_Success;
  }
} else if (!Param->isDependentType()) {
  CanQualType ParamUnqualType = CanParam.getUnqualifiedType(),
              ArgUnqualType = CanArg.getUnqualifiedType();
  bool Success =
      (TDF & TDF_AllowCompatibleFunctionType)
          ? S.isSameOrCompatibleFunctionType(ParamUnqualType, ArgUnqualType)
          : ParamUnqualType == ArgUnqualType;
  if (Success)
    return Sema::TDK_Success;
}

switch (Param->getTypeClass()) {
  // Non-canonical types cannot appear here.
1486#define NON_CANONICAL_TYPE(Class, Base) \
case Type::Class: llvm_unreachable("deducing non-canonical type: " #Class)::llvm::llvm_unreachable_internal("deducing non-canonical type: "
 #Class, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1487);
1488#define TYPE(Class, Base)
1489#include "clang/AST/TypeNodes.inc"

  case Type::TemplateTypeParm:
  case Type::SubstTemplateTypeParmPack:
    llvm_unreachable("Type nodes handled above")::llvm::llvm_unreachable_internal("Type nodes handled above",
 "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1493);

  // These types cannot be dependent, so simply check whether the types are
  // the same.
  case Type::Builtin:
  case Type::VariableArray:
  case Type::Vector:
  case Type::FunctionNoProto:
  case Type::Record:
  case Type::Enum:
  case Type::ObjCObject:
  case Type::ObjCInterface:
  case Type::ObjCObjectPointer:
    if (TDF & TDF_SkipNonDependent)
      return Sema::TDK_Success;

    if (TDF & TDF_IgnoreQualifiers) {
      Param = Param.getUnqualifiedType();
      Arg = Arg.getUnqualifiedType();
    }

    return Param == Arg? Sema::TDK_Success : Sema::TDK_NonDeducedMismatch;

  //     _Complex T   [placeholder extension]
  case Type::Complex:
    if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>())
      return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                  cast<ComplexType>(Param)->getElementType(),
                                  ComplexArg->getElementType(),
                                  Info, Deduced, TDF);

    return Sema::TDK_NonDeducedMismatch;

  //     _Atomic T   [extension]
  case Type::Atomic:
    if (const AtomicType *AtomicArg = Arg->getAs<AtomicType>())
      return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                     cast<AtomicType>(Param)->getValueType(),
                                     AtomicArg->getValueType(),
                                     Info, Deduced, TDF);

    return Sema::TDK_NonDeducedMismatch;

  //     T *
  case Type::Pointer: {
    QualType PointeeType;
    if (const PointerType *PointerArg = Arg->getAs<PointerType>()) {
      PointeeType = PointerArg->getPointeeType();
    } else if (const ObjCObjectPointerType *PointerArg
                 = Arg->getAs<ObjCObjectPointerType>()) {
      PointeeType = PointerArg->getPointeeType();
    } else {
      return Sema::TDK_NonDeducedMismatch;
    }

    unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass);
    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                   cast<PointerType>(Param)->getPointeeType(),
                                   PointeeType,
                                   Info, Deduced, SubTDF);
  }

  //     T &
  case Type::LValueReference: {
    const LValueReferenceType *ReferenceArg =
        Arg->getAs<LValueReferenceType>();
    if (!ReferenceArg)
      return Sema::TDK_NonDeducedMismatch;

    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                         cast<LValueReferenceType>(Param)->getPointeeType(),
                         ReferenceArg->getPointeeType(), Info, Deduced, 0);
  }

  //     T && [C++0x]
  case Type::RValueReference: {
    const RValueReferenceType *ReferenceArg =
        Arg->getAs<RValueReferenceType>();
    if (!ReferenceArg)
      return Sema::TDK_NonDeducedMismatch;

    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                           cast<RValueReferenceType>(Param)->getPointeeType(),
                           ReferenceArg->getPointeeType(),
                           Info, Deduced, 0);
  }

  //     T [] (implied, but not stated explicitly)
  case Type::IncompleteArray: {
    const IncompleteArrayType *IncompleteArrayArg =
      S.Context.getAsIncompleteArrayType(Arg);
    if (!IncompleteArrayArg)
      return Sema::TDK_NonDeducedMismatch;

    unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                  S.Context.getAsIncompleteArrayType(Param)->getElementType(),
                  IncompleteArrayArg->getElementType(),
                  Info, Deduced, SubTDF);
  }

  //     T [integer-constant]
  case Type::ConstantArray: {
    const ConstantArrayType *ConstantArrayArg =
      S.Context.getAsConstantArrayType(Arg);
    if (!ConstantArrayArg)
      return Sema::TDK_NonDeducedMismatch;

    const ConstantArrayType *ConstantArrayParm =
      S.Context.getAsConstantArrayType(Param);
    if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize())
      return Sema::TDK_NonDeducedMismatch;

    unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                         ConstantArrayParm->getElementType(),
                                         ConstantArrayArg->getElementType(),
                                         Info, Deduced, SubTDF);
  }

  //     type [i]
  case Type::DependentSizedArray: {
    const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg);
    if (!ArrayArg)
      return Sema::TDK_NonDeducedMismatch;

    unsigned SubTDF = TDF & TDF_IgnoreQualifiers;

    // Check the element type of the arrays
    const DependentSizedArrayType *DependentArrayParm
      = S.Context.getAsDependentSizedArrayType(Param);
    if (Sema::TemplateDeductionResult Result
          = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                        DependentArrayParm->getElementType(),
                                        ArrayArg->getElementType(),
                                        Info, Deduced, SubTDF))
      return Result;

    // Determine the array bound is something we can deduce.
    NonTypeTemplateParmDecl *NTTP
      = getDeducedParameterFromExpr(Info, DependentArrayParm->getSizeExpr());
    if (!NTTP)
      return Sema::TDK_Success;

    // We can perform template argument deduction for the given non-type
    // template parameter.
    assert(NTTP->getDepth() == Info.getDeducedDepth() &&((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1640, __PRETTY_FUNCTION__))
           "saw non-type template parameter with wrong depth")((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1640, __PRETTY_FUNCTION__));
    if (const ConstantArrayType *ConstantArrayArg
          = dyn_cast<ConstantArrayType>(ArrayArg)) {
      llvm::APSInt Size(ConstantArrayArg->getSize());
      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, Size,
                                           S.Context.getSizeType(),
                                           /*ArrayBound=*/true,
                                           Info, Deduced);
    }
    if (const DependentSizedArrayType *DependentArrayArg
          = dyn_cast<DependentSizedArrayType>(ArrayArg))
      if (DependentArrayArg->getSizeExpr())
        return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                             DependentArrayArg->getSizeExpr(),
                                             Info, Deduced);

    // Incomplete type does not match a dependently-sized array type
    return Sema::TDK_NonDeducedMismatch;
  }

  //     type(*)(T)
  //     T(*)()
  //     T(*)(T)
  case Type::FunctionProto: {
    unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList;
    const FunctionProtoType *FunctionProtoArg =
      dyn_cast<FunctionProtoType>(Arg);
    if (!FunctionProtoArg)
      return Sema::TDK_NonDeducedMismatch;

    const FunctionProtoType *FunctionProtoParam =
      cast<FunctionProtoType>(Param);

    if (FunctionProtoParam->getMethodQuals()
          != FunctionProtoArg->getMethodQuals() ||
        FunctionProtoParam->getRefQualifier()
          != FunctionProtoArg->getRefQualifier() ||
        FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic())
      return Sema::TDK_NonDeducedMismatch;

    // Check return types.
    if (auto Result = DeduceTemplateArgumentsByTypeMatch(
            S, TemplateParams, FunctionProtoParam->getReturnType(),
            FunctionProtoArg->getReturnType(), Info, Deduced, 0))
      return Result;

    // Check parameter types.
    if (auto Result = DeduceTemplateArguments(
            S, TemplateParams, FunctionProtoParam->param_type_begin(),
            FunctionProtoParam->getNumParams(),
            FunctionProtoArg->param_type_begin(),
            FunctionProtoArg->getNumParams(), Info, Deduced, SubTDF))
      return Result;

    if (TDF & TDF_AllowCompatibleFunctionType)
      return Sema::TDK_Success;

    // FIXME: Per core-2016/10/1019 (no corresponding core issue yet), permit
    // deducing through the noexcept-specifier if it's part of the canonical
    // type. libstdc++ relies on this.
    Expr *NoexceptExpr = FunctionProtoParam->getNoexceptExpr();
    if (NonTypeTemplateParmDecl *NTTP =
        NoexceptExpr ? getDeducedParameterFromExpr(Info, NoexceptExpr)
                     : nullptr) {
      assert(NTTP->getDepth() == Info.getDeducedDepth() &&((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1705, __PRETTY_FUNCTION__))
             "saw non-type template parameter with wrong depth")((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1705, __PRETTY_FUNCTION__));

      llvm::APSInt Noexcept(1);
      switch (FunctionProtoArg->canThrow()) {
      case CT_Cannot:
        Noexcept = 1;
        LLVM_FALLTHROUGH[[gnu::fallthrough]];

      case CT_Can:
        // We give E in noexcept(E) the "deduced from array bound" treatment.
        // FIXME: Should we?
        return DeduceNonTypeTemplateArgument(
            S, TemplateParams, NTTP, Noexcept, S.Context.BoolTy,
            /*ArrayBound*/true, Info, Deduced);

      case CT_Dependent:
        if (Expr *ArgNoexceptExpr = FunctionProtoArg->getNoexceptExpr())
          return DeduceNonTypeTemplateArgument(
              S, TemplateParams, NTTP, ArgNoexceptExpr, Info, Deduced);
        // Can't deduce anything from throw(T...).
        break;
      }
    }
    // FIXME: Detect non-deduced exception specification mismatches?
    //
    // Careful about [temp.deduct.call] and [temp.deduct.conv], which allow
    // top-level differences in noexcept-specifications.

    return Sema::TDK_Success;
  }

  case Type::InjectedClassName:
    // Treat a template's injected-class-name as if the template
    // specialization type had been used.
    Param = cast<InjectedClassNameType>(Param)
      ->getInjectedSpecializationType();
    assert(isa<TemplateSpecializationType>(Param) &&((isa<TemplateSpecializationType>(Param) && "injected class name is not a template specialization type"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateSpecializationType>(Param) && \"injected class name is not a template specialization type\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1742, __PRETTY_FUNCTION__))
           "injected class name is not a template specialization type")((isa<TemplateSpecializationType>(Param) && "injected class name is not a template specialization type"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateSpecializationType>(Param) && \"injected class name is not a template specialization type\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1742, __PRETTY_FUNCTION__));
    LLVM_FALLTHROUGH[[gnu::fallthrough]];

  //     template-name<T> (where template-name refers to a class template)
  //     template-name<i>
  //     TT<T>
  //     TT<i>
  //     TT<>
  case Type::TemplateSpecialization: {
    const TemplateSpecializationType *SpecParam =
        cast<TemplateSpecializationType>(Param);

    // When Arg cannot be a derived class, we can just try to deduce template
    // arguments from the template-id.
    const RecordType *RecordT = Arg->getAs<RecordType>();
    if (!(TDF & TDF_DerivedClass) || !RecordT)
      return DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, Info,
                                     Deduced);

    SmallVector<DeducedTemplateArgument, 8> DeducedOrig(Deduced.begin(),
                                                        Deduced.end());

    Sema::TemplateDeductionResult Result = DeduceTemplateArguments(
        S, TemplateParams, SpecParam, Arg, Info, Deduced);

    if (Result == Sema::TDK_Success)
      return Result;

    // We cannot inspect base classes as part of deduction when the type
    // is incomplete, so either instantiate any templates necessary to
    // complete the type, or skip over it if it cannot be completed.
    if (!S.isCompleteType(Info.getLocation(), Arg))
      return Result;

    // C++14 [temp.deduct.call] p4b3:
    //   If P is a class and P has the form simple-template-id, then the
    //   transformed A can be a derived class of the deduced A. Likewise if
    //   P is a pointer to a class of the form simple-template-id, the
    //   transformed A can be a pointer to a derived class pointed to by the
    //   deduced A.
    //
    //   These alternatives are considered only if type deduction would
    //   otherwise fail. If they yield more than one possible deduced A, the
    //   type deduction fails.

    // Reset the incorrectly deduced argument from above.
    Deduced = DeducedOrig;

    // Use data recursion to crawl through the list of base classes.
    // Visited contains the set of nodes we have already visited, while
    // ToVisit is our stack of records that we still need to visit.
    llvm::SmallPtrSet<const RecordType *, 8> Visited;
    SmallVector<const RecordType *, 8> ToVisit;
    ToVisit.push_back(RecordT);
    bool Successful = false;
    SmallVector<DeducedTemplateArgument, 8> SuccessfulDeduced;
    while (!ToVisit.empty()) {
      // Retrieve the next class in the inheritance hierarchy.
      const RecordType *NextT = ToVisit.pop_back_val();

      // If we have already seen this type, skip it.
      if (!Visited.insert(NextT).second)
        continue;

      // If this is a base class, try to perform template argument
      // deduction from it.
      if (NextT != RecordT) {
        TemplateDeductionInfo BaseInfo(Info.getLocation());
        Sema::TemplateDeductionResult BaseResult =
            DeduceTemplateArguments(S, TemplateParams, SpecParam,
                                    QualType(NextT, 0), BaseInfo, Deduced);

        // If template argument deduction for this base was successful,
        // note that we had some success. Otherwise, ignore any deductions
        // from this base class.
        if (BaseResult == Sema::TDK_Success) {
          // If we've already seen some success, then deduction fails due to
          // an ambiguity (temp.deduct.call p5).
          if (Successful)
            return Sema::TDK_MiscellaneousDeductionFailure;

          Successful = true;
          std::swap(SuccessfulDeduced, Deduced);

          Info.Param = BaseInfo.Param;
          Info.FirstArg = BaseInfo.FirstArg;
          Info.SecondArg = BaseInfo.SecondArg;
        }

        Deduced = DeducedOrig;
      }

      // Visit base classes
      CXXRecordDecl *Next = cast<CXXRecordDecl>(NextT->getDecl());
      for (const auto &Base : Next->bases()) {
        assert(Base.getType()->isRecordType() &&((Base.getType()->isRecordType() && "Base class that isn't a record?"
) ? static_cast<void> (0) : __assert_fail ("Base.getType()->isRecordType() && \"Base class that isn't a record?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1838, __PRETTY_FUNCTION__))
               "Base class that isn't a record?")((Base.getType()->isRecordType() && "Base class that isn't a record?"
) ? static_cast<void> (0) : __assert_fail ("Base.getType()->isRecordType() && \"Base class that isn't a record?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1838, __PRETTY_FUNCTION__));
        ToVisit.push_back(Base.getType()->getAs<RecordType>());
      }
    }

    if (Successful) {
      std::swap(SuccessfulDeduced, Deduced);
      return Sema::TDK_Success;
    }

    return Result;
  }

  //     T type::*
  //     T T::*
  //     T (type::*)()
  //     type (T::*)()
  //     type (type::*)(T)
  //     type (T::*)(T)
  //     T (type::*)(T)
  //     T (T::*)()
  //     T (T::*)(T)
  case Type::MemberPointer: {
    const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param);
    const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg);
    if (!MemPtrArg)
      return Sema::TDK_NonDeducedMismatch;

    QualType ParamPointeeType = MemPtrParam->getPointeeType();
    if (ParamPointeeType->isFunctionType())
      S.adjustMemberFunctionCC(ParamPointeeType, /*IsStatic=*/true,
                               /*IsCtorOrDtor=*/false, Info.getLocation());
    QualType ArgPointeeType = MemPtrArg->getPointeeType();
    if (ArgPointeeType->isFunctionType())
      S.adjustMemberFunctionCC(ArgPointeeType, /*IsStatic=*/true,
                               /*IsCtorOrDtor=*/false, Info.getLocation());

    if (Sema::TemplateDeductionResult Result
          = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                               ParamPointeeType,
                                               ArgPointeeType,
                                               Info, Deduced,
                                               TDF & TDF_IgnoreQualifiers))
      return Result;

    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                         QualType(MemPtrParam->getClass(), 0),
                                         QualType(MemPtrArg->getClass(), 0),
                                         Info, Deduced,
                                         TDF & TDF_IgnoreQualifiers);
  }

  //     (clang extension)
  //
  //     type(^)(T)
  //     T(^)()
  //     T(^)(T)
  case Type::BlockPointer: {
    const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param);
    const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg);

    if (!BlockPtrArg)
      return Sema::TDK_NonDeducedMismatch;

    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                              BlockPtrParam->getPointeeType(),
                                              BlockPtrArg->getPointeeType(),
                                              Info, Deduced, 0);
  }

  //     (clang extension)
  //
  //     T __attribute__(((ext_vector_type(<integral constant>))))
  case Type::ExtVector: {
    const ExtVectorType *VectorParam = cast<ExtVectorType>(Param);
    if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
      // Make sure that the vectors have the same number of elements.
      if (VectorParam->getNumElements() != VectorArg->getNumElements())
        return Sema::TDK_NonDeducedMismatch;

      // Perform deduction on the element types.
      return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                                VectorParam->getElementType(),
                                                VectorArg->getElementType(),
                                                Info, Deduced, TDF);
    }

    if (const DependentSizedExtVectorType *VectorArg
                              = dyn_cast<DependentSizedExtVectorType>(Arg)) {
      // We can't check the number of elements, since the argument has a
      // dependent number of elements. This can only occur during partial
      // ordering.

      // Perform deduction on the element types.
      return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                                VectorParam->getElementType(),
                                                VectorArg->getElementType(),
                                                Info, Deduced, TDF);
    }

    return Sema::TDK_NonDeducedMismatch;
  }

  case Type::DependentVector: {
    const auto *VectorParam = cast<DependentVectorType>(Param);

    if (const auto *VectorArg = dyn_cast<VectorType>(Arg)) {
      // Perform deduction on the element types.
      if (Sema::TemplateDeductionResult Result =
              DeduceTemplateArgumentsByTypeMatch(
                  S, TemplateParams, VectorParam->getElementType(),
                  VectorArg->getElementType(), Info, Deduced, TDF))
        return Result;

      // Perform deduction on the vector size, if we can.
      NonTypeTemplateParmDecl *NTTP =
          getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
      if (!NTTP)
        return Sema::TDK_Success;

      llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
      ArgSize = VectorArg->getNumElements();
      // Note that we use the "array bound" rules here; just like in that
      // case, we don't have any particular type for the vector size, but
      // we can provide one if necessary.
      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize,
                                           S.Context.UnsignedIntTy, true,
                                           Info, Deduced);
    }

    if (const auto *VectorArg = dyn_cast<DependentVectorType>(Arg)) {
      // Perform deduction on the element types.
      if (Sema::TemplateDeductionResult Result =
              DeduceTemplateArgumentsByTypeMatch(
                  S, TemplateParams, VectorParam->getElementType(),
                  VectorArg->getElementType(), Info, Deduced, TDF))
        return Result;

      // Perform deduction on the vector size, if we can.
      NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
          Info, VectorParam->getSizeExpr());
      if (!NTTP)
        return Sema::TDK_Success;

      return DeduceNonTypeTemplateArgument(
          S, TemplateParams, NTTP, VectorArg->getSizeExpr(), Info, Deduced);
    }

    return Sema::TDK_NonDeducedMismatch;
  }

  //     (clang extension)
  //
  //     T __attribute__(((ext_vector_type(N))))
  case Type::DependentSizedExtVector: {
    const DependentSizedExtVectorType *VectorParam
      = cast<DependentSizedExtVectorType>(Param);

    if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
      // Perform deduction on the element types.
      if (Sema::TemplateDeductionResult Result
            = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                                VectorParam->getElementType(),
                                                 VectorArg->getElementType(),
                                                 Info, Deduced, TDF))
        return Result;

      // Perform deduction on the vector size, if we can.
      NonTypeTemplateParmDecl *NTTP
        = getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
      if (!NTTP)
        return Sema::TDK_Success;

      llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
      ArgSize = VectorArg->getNumElements();
      // Note that we use the "array bound" rules here; just like in that
      // case, we don't have any particular type for the vector size, but
      // we can provide one if necessary.
      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize,
                                           S.Context.IntTy, true, Info,
                                           Deduced);
    }

    if (const DependentSizedExtVectorType *VectorArg
                              = dyn_cast<DependentSizedExtVectorType>(Arg)) {
      // Perform deduction on the element types.
      if (Sema::TemplateDeductionResult Result
          = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                               VectorParam->getElementType(),
                                               VectorArg->getElementType(),
                                               Info, Deduced, TDF))
        return Result;

      // Perform deduction on the vector size, if we can.
      NonTypeTemplateParmDecl *NTTP
        = getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
      if (!NTTP)
        return Sema::TDK_Success;

      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                           VectorArg->getSizeExpr(),
                                           Info, Deduced);
    }

    return Sema::TDK_NonDeducedMismatch;
  }

  //     (clang extension)
  //
  //     T __attribute__(((address_space(N))))
  case Type::DependentAddressSpace: {
    const DependentAddressSpaceType *AddressSpaceParam =
        cast<DependentAddressSpaceType>(Param);

    if (const DependentAddressSpaceType *AddressSpaceArg =
            dyn_cast<DependentAddressSpaceType>(Arg)) {
      // Perform deduction on the pointer type.
      if (Sema::TemplateDeductionResult Result =
              DeduceTemplateArgumentsByTypeMatch(
                  S, TemplateParams, AddressSpaceParam->getPointeeType(),
                  AddressSpaceArg->getPointeeType(), Info, Deduced, TDF))
        return Result;

      // Perform deduction on the address space, if we can.
      NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
          Info, AddressSpaceParam->getAddrSpaceExpr());
      if (!NTTP)
        return Sema::TDK_Success;

      return DeduceNonTypeTemplateArgument(
          S, TemplateParams, NTTP, AddressSpaceArg->getAddrSpaceExpr(), Info,
          Deduced);
    }

    if (isTargetAddressSpace(Arg.getAddressSpace())) {
      llvm::APSInt ArgAddressSpace(S.Context.getTypeSize(S.Context.IntTy),
                                   false);
      ArgAddressSpace = toTargetAddressSpace(Arg.getAddressSpace());

      // Perform deduction on the pointer types.
      if (Sema::TemplateDeductionResult Result =
              DeduceTemplateArgumentsByTypeMatch(
                  S, TemplateParams, AddressSpaceParam->getPointeeType(),
                  S.Context.removeAddrSpaceQualType(Arg), Info, Deduced, TDF))
        return Result;

      // Perform deduction on the address space, if we can.
      NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
          Info, AddressSpaceParam->getAddrSpaceExpr());
      if (!NTTP)
        return Sema::TDK_Success;

      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                           ArgAddressSpace, S.Context.IntTy,
                                           true, Info, Deduced);
    }

    return Sema::TDK_NonDeducedMismatch;
  }

  case Type::TypeOfExpr:
  case Type::TypeOf:
  case Type::DependentName:
  case Type::UnresolvedUsing:
  case Type::Decltype:
  case Type::UnaryTransform:
  case Type::Auto:
  case Type::DeducedTemplateSpecialization:
  case Type::DependentTemplateSpecialization:
  case Type::PackExpansion:
  case Type::Pipe:
    // No template argument deduction for these types
    return Sema::TDK_Success;
}

llvm_unreachable("Invalid Type Class!")::llvm::llvm_unreachable_internal("Invalid Type Class!", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2113);
2114}

2116static Sema::TemplateDeductionResult
2117DeduceTemplateArguments(Sema &S,
                      TemplateParameterList *TemplateParams,
                      const TemplateArgument &Param,
                      TemplateArgument Arg,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
// If the template argument is a pack expansion, perform template argument
// deduction against the pattern of that expansion. This only occurs during
// partial ordering.
if (Arg.isPackExpansion())
  Arg = Arg.getPackExpansionPattern();

switch (Param.getKind()) {
case TemplateArgument::Null:
  llvm_unreachable("Null template argument in parameter list")::llvm::llvm_unreachable_internal("Null template argument in parameter list"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2131);

case TemplateArgument::Type:
  if (Arg.getKind() == TemplateArgument::Type)
    return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                              Param.getAsType(),
                                              Arg.getAsType(),
                                              Info, Deduced, 0);
  Info.FirstArg = Param;
  Info.SecondArg = Arg;
  return Sema::TDK_NonDeducedMismatch;

case TemplateArgument::Template:
  if (Arg.getKind() == TemplateArgument::Template)
    return DeduceTemplateArguments(S, TemplateParams,
                                   Param.getAsTemplate(),
                                   Arg.getAsTemplate(), Info, Deduced);
  Info.FirstArg = Param;
  Info.SecondArg = Arg;
  return Sema::TDK_NonDeducedMismatch;

case TemplateArgument::TemplateExpansion:
  llvm_unreachable("caller should handle pack expansions")::llvm::llvm_unreachable_internal("caller should handle pack expansions"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2153);

case TemplateArgument::Declaration:
  if (Arg.getKind() == TemplateArgument::Declaration &&
      isSameDeclaration(Param.getAsDecl(), Arg.getAsDecl()))
    return Sema::TDK_Success;

  Info.FirstArg = Param;
  Info.SecondArg = Arg;
  return Sema::TDK_NonDeducedMismatch;

case TemplateArgument::NullPtr:
  if (Arg.getKind() == TemplateArgument::NullPtr &&
      S.Context.hasSameType(Param.getNullPtrType(), Arg.getNullPtrType()))
    return Sema::TDK_Success;

  Info.FirstArg = Param;
  Info.SecondArg = Arg;
  return Sema::TDK_NonDeducedMismatch;

case TemplateArgument::Integral:
  if (Arg.getKind() == TemplateArgument::Integral) {
    if (hasSameExtendedValue(Param.getAsIntegral(), Arg.getAsIntegral()))
      return Sema::TDK_Success;

    Info.FirstArg = Param;
    Info.SecondArg = Arg;
    return Sema::TDK_NonDeducedMismatch;
  }

  if (Arg.getKind() == TemplateArgument::Expression) {
    Info.FirstArg = Param;
    Info.SecondArg = Arg;
    return Sema::TDK_NonDeducedMismatch;
  }

  Info.FirstArg = Param;
  Info.SecondArg = Arg;
  return Sema::TDK_NonDeducedMismatch;

case TemplateArgument::Expression:
  if (NonTypeTemplateParmDecl *NTTP
        = getDeducedParameterFromExpr(Info, Param.getAsExpr())) {
    if (Arg.getKind() == TemplateArgument::Integral)
      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                           Arg.getAsIntegral(),
                                           Arg.getIntegralType(),
                                           /*ArrayBound=*/false,
                                           Info, Deduced);
    if (Arg.getKind() == TemplateArgument::NullPtr)
      return DeduceNullPtrTemplateArgument(S, TemplateParams, NTTP,
                                           Arg.getNullPtrType(),
                                           Info, Deduced);
    if (Arg.getKind() == TemplateArgument::Expression)
      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                           Arg.getAsExpr(), Info, Deduced);
    if (Arg.getKind() == TemplateArgument::Declaration)
      return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
                                           Arg.getAsDecl(),
                                           Arg.getParamTypeForDecl(),
                                           Info, Deduced);

    Info.FirstArg = Param;
    Info.SecondArg = Arg;
    return Sema::TDK_NonDeducedMismatch;
  }

  // Can't deduce anything, but that's okay.
  return Sema::TDK_Success;

case TemplateArgument::Pack:
  llvm_unreachable("Argument packs should be expanded by the caller!")::llvm::llvm_unreachable_internal("Argument packs should be expanded by the caller!"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2224);
}

llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2227);
2228}

2230/// Determine whether there is a template argument to be used for
2231/// deduction.
2232///
2233/// This routine "expands" argument packs in-place, overriding its input
2234/// parameters so that \c Args[ArgIdx] will be the available template argument.
2235///
2236/// \returns true if there is another template argument (which will be at
2237/// \c Args[ArgIdx]), false otherwise.
2238static bool hasTemplateArgumentForDeduction(ArrayRef<TemplateArgument> &Args,
                                          unsigned &ArgIdx) {
if (ArgIdx == Args.size())
  return false;

const TemplateArgument &Arg = Args[ArgIdx];
if (Arg.getKind() != TemplateArgument::Pack)
  return true;

assert(ArgIdx == Args.size() - 1 && "Pack not at the end of argument list?")((ArgIdx == Args.size() - 1 && "Pack not at the end of argument list?"
) ? static_cast<void> (0) : __assert_fail ("ArgIdx == Args.size() - 1 && \"Pack not at the end of argument list?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2247, __PRETTY_FUNCTION__));
Args = Arg.pack_elements();
ArgIdx = 0;
return ArgIdx < Args.size();
2251}

2253/// Determine whether the given set of template arguments has a pack
2254/// expansion that is not the last template argument.
2255static bool hasPackExpansionBeforeEnd(ArrayRef<TemplateArgument> Args) {
bool FoundPackExpansion = false;
for (const auto &A : Args) {
  if (FoundPackExpansion)
    return true;

  if (A.getKind() == TemplateArgument::Pack)
    return hasPackExpansionBeforeEnd(A.pack_elements());

  // FIXME: If this is a fixed-arity pack expansion from an outer level of
  // templates, it should not be treated as a pack expansion.
  if (A.isPackExpansion())
    FoundPackExpansion = true;
}

return false;
2271}

2273static Sema::TemplateDeductionResult
2274DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
                      ArrayRef<TemplateArgument> Params,
                      ArrayRef<TemplateArgument> Args,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                      bool NumberOfArgumentsMustMatch) {
// C++0x [temp.deduct.type]p9:
//   If the template argument list of P contains a pack expansion that is not
//   the last template argument, the entire template argument list is a
//   non-deduced context.
if (hasPackExpansionBeforeEnd(Params))
  return Sema::TDK_Success;

// C++0x [temp.deduct.type]p9:
//   If P has a form that contains <T> or <i>, then each argument Pi of the
//   respective template argument list P is compared with the corresponding
//   argument Ai of the corresponding template argument list of A.
unsigned ArgIdx = 0, ParamIdx = 0;
for (; hasTemplateArgumentForDeduction(Params, ParamIdx); ++ParamIdx) {
  if (!Params[ParamIdx].isPackExpansion()) {
    // The simple case: deduce template arguments by matching Pi and Ai.

    // Check whether we have enough arguments.
    if (!hasTemplateArgumentForDeduction(Args, ArgIdx))
      return NumberOfArgumentsMustMatch
                 ? Sema::TDK_MiscellaneousDeductionFailure
                 : Sema::TDK_Success;

    // C++1z [temp.deduct.type]p9:
    //   During partial ordering, if Ai was originally a pack expansion [and]
    //   Pi is not a pack expansion, template argument deduction fails.
    if (Args[ArgIdx].isPackExpansion())
      return Sema::TDK_MiscellaneousDeductionFailure;

    // Perform deduction for this Pi/Ai pair.
    if (Sema::TemplateDeductionResult Result
          = DeduceTemplateArguments(S, TemplateParams,
                                    Params[ParamIdx], Args[ArgIdx],
                                    Info, Deduced))
      return Result;

    // Move to the next argument.
    ++ArgIdx;
    continue;
  }

  // The parameter is a pack expansion.

  // C++0x [temp.deduct.type]p9:
  //   If Pi is a pack expansion, then the pattern of Pi is compared with
  //   each remaining argument in the template argument list of A. Each
  //   comparison deduces template arguments for subsequent positions in the
  //   template parameter packs expanded by Pi.
  TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern();

  // Prepare to deduce the packs within the pattern.
  PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);

  // Keep track of the deduced template arguments for each parameter pack
  // expanded by this pack expansion (the outer index) and for each
  // template argument (the inner SmallVectors).
  for (; hasTemplateArgumentForDeduction(Args, ArgIdx) &&
         PackScope.hasNextElement();
       ++ArgIdx) {
    // Deduce template arguments from the pattern.
    if (Sema::TemplateDeductionResult Result
          = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx],
                                    Info, Deduced))
      return Result;

    PackScope.nextPackElement();
  }

  // Build argument packs for each of the parameter packs expanded by this
  // pack expansion.
  if (auto Result = PackScope.finish())
    return Result;
}

return Sema::TDK_Success;
2354}

2356static Sema::TemplateDeductionResult
2357DeduceTemplateArguments(Sema &S,
                      TemplateParameterList *TemplateParams,
                      const TemplateArgumentList &ParamList,
                      const TemplateArgumentList &ArgList,
                      TemplateDeductionInfo &Info,
                      SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
return DeduceTemplateArguments(S, TemplateParams, ParamList.asArray(),
                               ArgList.asArray(), Info, Deduced,
                               /*NumberOfArgumentsMustMatch*/false);
2366}

2368/// Determine whether two template arguments are the same.
2369static bool isSameTemplateArg(ASTContext &Context,
                            TemplateArgument X,
                            const TemplateArgument &Y,
                            bool PackExpansionMatchesPack = false) {
// If we're checking deduced arguments (X) against original arguments (Y),
// we will have flattened packs to non-expansions in X.
if (PackExpansionMatchesPack && X.isPackExpansion() && !Y.isPackExpansion())
  X = X.getPackExpansionPattern();

if (X.getKind() != Y.getKind())
  return false;

switch (X.getKind()) {
  case TemplateArgument::Null:
    llvm_unreachable("Comparing NULL template argument")::llvm::llvm_unreachable_internal("Comparing NULL template argument"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2383);

  case TemplateArgument::Type:
    return Context.getCanonicalType(X.getAsType()) ==
           Context.getCanonicalType(Y.getAsType());

  case TemplateArgument::Declaration:
    return isSameDeclaration(X.getAsDecl(), Y.getAsDecl());

  case TemplateArgument::NullPtr:
    return Context.hasSameType(X.getNullPtrType(), Y.getNullPtrType());

  case TemplateArgument::Template:
  case TemplateArgument::TemplateExpansion:
    return Context.getCanonicalTemplateName(
                  X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() ==
           Context.getCanonicalTemplateName(
                  Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer();

  case TemplateArgument::Integral:
    return hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral());

  case TemplateArgument::Expression: {
    llvm::FoldingSetNodeID XID, YID;
    X.getAsExpr()->Profile(XID, Context, true);
    Y.getAsExpr()->Profile(YID, Context, true);
    return XID == YID;
  }

  case TemplateArgument::Pack:
    if (X.pack_size() != Y.pack_size())
      return false;

    for (TemplateArgument::pack_iterator XP = X.pack_begin(),
                                      XPEnd = X.pack_end(),
                                         YP = Y.pack_begin();
         XP != XPEnd; ++XP, ++YP)
      if (!isSameTemplateArg(Context, *XP, *YP, PackExpansionMatchesPack))
        return false;

    return true;
}

llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2426);
2427}

2429/// Allocate a TemplateArgumentLoc where all locations have
2430/// been initialized to the given location.
2431///
2432/// \param Arg The template argument we are producing template argument
2433/// location information for.
2434///
2435/// \param NTTPType For a declaration template argument, the type of
2436/// the non-type template parameter that corresponds to this template
2437/// argument. Can be null if no type sugar is available to add to the
2438/// type from the template argument.
2439///
2440/// \param Loc The source location to use for the resulting template
2441/// argument.
2442TemplateArgumentLoc
2443Sema::getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
                                  QualType NTTPType, SourceLocation Loc) {
switch (Arg.getKind()) {
case TemplateArgument::Null:
  llvm_unreachable("Can't get a NULL template argument here")::llvm::llvm_unreachable_internal("Can't get a NULL template argument here"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2447);

case TemplateArgument::Type:
  return TemplateArgumentLoc(
      Arg, Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc));

case TemplateArgument::Declaration: {
  if (NTTPType.isNull())
    NTTPType = Arg.getParamTypeForDecl();
  Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
                .getAs<Expr>();
  return TemplateArgumentLoc(TemplateArgument(E), E);
}

case TemplateArgument::NullPtr: {
  if (NTTPType.isNull())
    NTTPType = Arg.getNullPtrType();
  Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
                .getAs<Expr>();
  return TemplateArgumentLoc(TemplateArgument(NTTPType, /*isNullPtr*/true),
                             E);
}

case TemplateArgument::Integral: {
  Expr *E =
      BuildExpressionFromIntegralTemplateArgument(Arg, Loc).getAs<Expr>();
  return TemplateArgumentLoc(TemplateArgument(E), E);
}

  case TemplateArgument::Template:
  case TemplateArgument::TemplateExpansion: {
    NestedNameSpecifierLocBuilder Builder;
    TemplateName Template = Arg.getAsTemplate();
    if (DependentTemplateName *DTN = Template.getAsDependentTemplateName())
      Builder.MakeTrivial(Context, DTN->getQualifier(), Loc);
    else if (QualifiedTemplateName *QTN =
                 Template.getAsQualifiedTemplateName())
      Builder.MakeTrivial(Context, QTN->getQualifier(), Loc);

    if (Arg.getKind() == TemplateArgument::Template)
      return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(Context),
                                 Loc);

    return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(Context),
                               Loc, Loc);
  }

case TemplateArgument::Expression:
  return TemplateArgumentLoc(Arg, Arg.getAsExpr());

case TemplateArgument::Pack:
  return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo());
}

llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2501);
2502}

2504/// Convert the given deduced template argument and add it to the set of
2505/// fully-converted template arguments.
2506static bool
2507ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param,
                             DeducedTemplateArgument Arg,
                             NamedDecl *Template,
                             TemplateDeductionInfo &Info,
                             bool IsDeduced,
                             SmallVectorImpl<TemplateArgument> &Output) {
auto ConvertArg = [&](DeducedTemplateArgument Arg,
                      unsigned ArgumentPackIndex) {
  // Convert the deduced template argument into a template
  // argument that we can check, almost as if the user had written
  // the template argument explicitly.
  TemplateArgumentLoc ArgLoc =
      S.getTrivialTemplateArgumentLoc(Arg, QualType(), Info.getLocation());

  // Check the template argument, converting it as necessary.
  return S.CheckTemplateArgument(
      Param, ArgLoc, Template, Template->getLocation(),
      Template->getSourceRange().getEnd(), ArgumentPackIndex, Output,
      IsDeduced
          ? (Arg.wasDeducedFromArrayBound() ? Sema::CTAK_DeducedFromArrayBound
                                            : Sema::CTAK_Deduced)
          : Sema::CTAK_Specified);
};

if (Arg.getKind() == TemplateArgument::Pack) {
  // This is a template argument pack, so check each of its arguments against
  // the template parameter.
  SmallVector<TemplateArgument, 2> PackedArgsBuilder;
  for (const auto &P : Arg.pack_elements()) {
    // When converting the deduced template argument, append it to the
    // general output list. We need to do this so that the template argument
    // checking logic has all of the prior template arguments available.
    DeducedTemplateArgument InnerArg(P);
    InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound());
    assert(InnerArg.getKind() != TemplateArgument::Pack &&((InnerArg.getKind() != TemplateArgument::Pack && "deduced nested pack"
) ? static_cast<void> (0) : __assert_fail ("InnerArg.getKind() != TemplateArgument::Pack && \"deduced nested pack\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2542, __PRETTY_FUNCTION__))
           "deduced nested pack")((InnerArg.getKind() != TemplateArgument::Pack && "deduced nested pack"
) ? static_cast<void> (0) : __assert_fail ("InnerArg.getKind() != TemplateArgument::Pack && \"deduced nested pack\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2542, __PRETTY_FUNCTION__));
    if (P.isNull()) {
      // We deduced arguments for some elements of this pack, but not for
      // all of them. This happens if we get a conditionally-non-deduced
      // context in a pack expansion (such as an overload set in one of the
      // arguments).
      S.Diag(Param->getLocation(),
             diag::err_template_arg_deduced_incomplete_pack)
        << Arg << Param;
      return true;
    }
    if (ConvertArg(InnerArg, PackedArgsBuilder.size()))
      return true;

    // Move the converted template argument into our argument pack.
    PackedArgsBuilder.push_back(Output.pop_back_val());
  }

  // If the pack is empty, we still need to substitute into the parameter
  // itself, in case that substitution fails.
  if (PackedArgsBuilder.empty()) {
    LocalInstantiationScope Scope(S);
    TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Output);
    MultiLevelTemplateArgumentList Args(TemplateArgs);

    if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
      Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template,
                                       NTTP, Output,
                                       Template->getSourceRange());
      if (Inst.isInvalid() ||
          S.SubstType(NTTP->getType(), Args, NTTP->getLocation(),
                      NTTP->getDeclName()).isNull())
        return true;
    } else if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(Param)) {
      Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template,
                                       TTP, Output,
                                       Template->getSourceRange());
      if (Inst.isInvalid() || !S.SubstDecl(TTP, S.CurContext, Args))
        return true;
    }
    // For type parameters, no substitution is ever required.
  }

  // Create the resulting argument pack.
  Output.push_back(
      TemplateArgument::CreatePackCopy(S.Context, PackedArgsBuilder));
  return false;
}

return ConvertArg(Arg, 0);
2592}

2594// FIXME: This should not be a template, but
2595// ClassTemplatePartialSpecializationDecl sadly does not derive from
2596// TemplateDecl.
2597template<typename TemplateDeclT>
2598static Sema::TemplateDeductionResult ConvertDeducedTemplateArguments(
  Sema &S, TemplateDeclT *Template, bool IsDeduced,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced,
  TemplateDeductionInfo &Info, SmallVectorImpl<TemplateArgument> &Builder,
  LocalInstantiationScope *CurrentInstantiationScope = nullptr,
  unsigned NumAlreadyConverted = 0, bool PartialOverloading = false) {
TemplateParameterList *TemplateParams = Template->getTemplateParameters();

for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
  NamedDecl *Param = TemplateParams->getParam(I);

  // C++0x [temp.arg.explicit]p3:
  //    A trailing template parameter pack (14.5.3) not otherwise deduced will
  //    be deduced to an empty sequence of template arguments.
  // FIXME: Where did the word "trailing" come from?
  if (Deduced[I].isNull() && Param->isTemplateParameterPack()) {
    if (auto Result = PackDeductionScope(S, TemplateParams, Deduced, Info, I)
                          .finish(/*TreatNoDeductionsAsNonDeduced*/false))
      return Result;
  }

  if (!Deduced[I].isNull()) {
    if (I < NumAlreadyConverted) {
      // We may have had explicitly-specified template arguments for a
      // template parameter pack (that may or may not have been extended
      // via additional deduced arguments).
      if (Param->isParameterPack() && CurrentInstantiationScope &&
          CurrentInstantiationScope->getPartiallySubstitutedPack() == Param) {
        // Forget the partially-substituted pack; its substitution is now
        // complete.
        CurrentInstantiationScope->ResetPartiallySubstitutedPack();
        // We still need to check the argument in case it was extended by
        // deduction.
      } else {
        // We have already fully type-checked and converted this
        // argument, because it was explicitly-specified. Just record the
        // presence of this argument.
        Builder.push_back(Deduced[I]);
        continue;
      }
    }

    // We may have deduced this argument, so it still needs to be
    // checked and converted.
    if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], Template, Info,
                                       IsDeduced, Builder)) {
      Info.Param = makeTemplateParameter(Param);
      // FIXME: These template arguments are temporary. Free them!
      Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
      return Sema::TDK_SubstitutionFailure;
    }

    continue;
  }

  // Substitute into the default template argument, if available.
  bool HasDefaultArg = false;
  TemplateDecl *TD = dyn_cast<TemplateDecl>(Template);
  if (!TD) {
    assert(isa<ClassTemplatePartialSpecializationDecl>(Template) ||((isa<ClassTemplatePartialSpecializationDecl>(Template)
 || isa<VarTemplatePartialSpecializationDecl>(Template)
) ? static_cast<void> (0) : __assert_fail ("isa<ClassTemplatePartialSpecializationDecl>(Template) || isa<VarTemplatePartialSpecializationDecl>(Template)"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2658, __PRETTY_FUNCTION__))
           isa<VarTemplatePartialSpecializationDecl>(Template))((isa<ClassTemplatePartialSpecializationDecl>(Template)
 || isa<VarTemplatePartialSpecializationDecl>(Template)
) ? static_cast<void> (0) : __assert_fail ("isa<ClassTemplatePartialSpecializationDecl>(Template) || isa<VarTemplatePartialSpecializationDecl>(Template)"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2658, __PRETTY_FUNCTION__));
    return Sema::TDK_Incomplete;
  }

  TemplateArgumentLoc DefArg = S.SubstDefaultTemplateArgumentIfAvailable(
      TD, TD->getLocation(), TD->getSourceRange().getEnd(), Param, Builder,
      HasDefaultArg);

  // If there was no default argument, deduction is incomplete.
  if (DefArg.getArgument().isNull()) {
    Info.Param = makeTemplateParameter(
        const_cast<NamedDecl *>(TemplateParams->getParam(I)));
    Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
    if (PartialOverloading) break;

    return HasDefaultArg ? Sema::TDK_SubstitutionFailure
                         : Sema::TDK_Incomplete;
  }

  // Check whether we can actually use the default argument.
  if (S.CheckTemplateArgument(Param, DefArg, TD, TD->getLocation(),
                              TD->getSourceRange().getEnd(), 0, Builder,
                              Sema::CTAK_Specified)) {
    Info.Param = makeTemplateParameter(
                       const_cast<NamedDecl *>(TemplateParams->getParam(I)));
    // FIXME: These template arguments are temporary. Free them!
    Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
    return Sema::TDK_SubstitutionFailure;
  }

  // If we get here, we successfully used the default template argument.
}

return Sema::TDK_Success;
2692}

2694static DeclContext *getAsDeclContextOrEnclosing(Decl *D) {
if (auto *DC = dyn_cast<DeclContext>(D))
  return DC;
return D->getDeclContext();
2698}

2700template<typename T> struct IsPartialSpecialization {
static constexpr bool value = false;
2702};
2703template<>
2704struct IsPartialSpecialization<ClassTemplatePartialSpecializationDecl> {
static constexpr bool value = true;
2706};
2707template<>
2708struct IsPartialSpecialization<VarTemplatePartialSpecializationDecl> {
static constexpr bool value = true;
2710};

2712/// Complete template argument deduction for a partial specialization.
2713template <typename T>
2714static typename std::enable_if<IsPartialSpecialization<T>::value,
                             Sema::TemplateDeductionResult>::type
2716FinishTemplateArgumentDeduction(
  Sema &S, T *Partial, bool IsPartialOrdering,
  const TemplateArgumentList &TemplateArgs,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced,
  TemplateDeductionInfo &Info) {
// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::Unevaluated);
Sema::SFINAETrap Trap(S);

Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Partial));

// C++ [temp.deduct.type]p2:
//   [...] or if any template argument remains neither deduced nor
//   explicitly specified, template argument deduction fails.
SmallVector<TemplateArgument, 4> Builder;
if (auto Result = ConvertDeducedTemplateArguments(
        S, Partial, IsPartialOrdering, Deduced, Info, Builder))
  return Result;

// Form the template argument list from the deduced template arguments.
TemplateArgumentList *DeducedArgumentList
  = TemplateArgumentList::CreateCopy(S.Context, Builder);

Info.reset(DeducedArgumentList);

// Substitute the deduced template arguments into the template
// arguments of the class template partial specialization, and
// verify that the instantiated template arguments are both valid
// and are equivalent to the template arguments originally provided
// to the class template.
LocalInstantiationScope InstScope(S);
auto *Template = Partial->getSpecializedTemplate();
const ASTTemplateArgumentListInfo *PartialTemplArgInfo =
    Partial->getTemplateArgsAsWritten();
const TemplateArgumentLoc *PartialTemplateArgs =
    PartialTemplArgInfo->getTemplateArgs();

TemplateArgumentListInfo InstArgs(PartialTemplArgInfo->LAngleLoc,
                                  PartialTemplArgInfo->RAngleLoc);

if (S.Subst(PartialTemplateArgs, PartialTemplArgInfo->NumTemplateArgs,
            InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) {
  unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx;
  if (ParamIdx >= Partial->getTemplateParameters()->size())
    ParamIdx = Partial->getTemplateParameters()->size() - 1;

  Decl *Param = const_cast<NamedDecl *>(
      Partial->getTemplateParameters()->getParam(ParamIdx));
  Info.Param = makeTemplateParameter(Param);
  Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument();
  return Sema::TDK_SubstitutionFailure;
}

SmallVector<TemplateArgument, 4> ConvertedInstArgs;
if (S.CheckTemplateArgumentList(Template, Partial->getLocation(), InstArgs,
                                false, ConvertedInstArgs))
  return Sema::TDK_SubstitutionFailure;

TemplateParameterList *TemplateParams = Template->getTemplateParameters();
for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
  TemplateArgument InstArg = ConvertedInstArgs.data()[I];
  if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) {
    Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
    Info.FirstArg = TemplateArgs[I];
    Info.SecondArg = InstArg;
    return Sema::TDK_NonDeducedMismatch;
  }
}

if (Trap.hasErrorOccurred())
  return Sema::TDK_SubstitutionFailure;

return Sema::TDK_Success;
2790}

2792/// Complete template argument deduction for a class or variable template,
2793/// when partial ordering against a partial specialization.
2794// FIXME: Factor out duplication with partial specialization version above.
2795static Sema::TemplateDeductionResult FinishTemplateArgumentDeduction(
  Sema &S, TemplateDecl *Template, bool PartialOrdering,
  const TemplateArgumentList &TemplateArgs,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced,
  TemplateDeductionInfo &Info) {
// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    S, Sema::ExpressionEvaluationContext::Unevaluated);
Sema::SFINAETrap Trap(S);

Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Template));

// C++ [temp.deduct.type]p2:
//   [...] or if any template argument remains neither deduced nor
//   explicitly specified, template argument deduction fails.
SmallVector<TemplateArgument, 4> Builder;
if (auto Result = ConvertDeducedTemplateArguments(
        S, Template, /*IsDeduced*/PartialOrdering, Deduced, Info, Builder))
  return Result;

// Check that we produced the correct argument list.
TemplateParameterList *TemplateParams = Template->getTemplateParameters();
for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
  TemplateArgument InstArg = Builder[I];
  if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg,
                         /*PackExpansionMatchesPack*/true)) {
    Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
    Info.FirstArg = TemplateArgs[I];
    Info.SecondArg = InstArg;
    return Sema::TDK_NonDeducedMismatch;
  }
}

if (Trap.hasErrorOccurred())
  return Sema::TDK_SubstitutionFailure;

return Sema::TDK_Success;
2832}


2835/// Perform template argument deduction to determine whether
2836/// the given template arguments match the given class template
2837/// partial specialization per C++ [temp.class.spec.match].
2838Sema::TemplateDeductionResult
2839Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
                            const TemplateArgumentList &TemplateArgs,
                            TemplateDeductionInfo &Info) {
if (Partial->isInvalidDecl())
  return TDK_Invalid;

// C++ [temp.class.spec.match]p2:
//   A partial specialization matches a given actual template
//   argument list if the template arguments of the partial
//   specialization can be deduced from the actual template argument
//   list (14.8.2).

// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);
SFINAETrap Trap(*this);

SmallVector<DeducedTemplateArgument, 4> Deduced;
Deduced.resize(Partial->getTemplateParameters()->size());
if (TemplateDeductionResult Result
      = ::DeduceTemplateArguments(*this,
                                  Partial->getTemplateParameters(),
                                  Partial->getTemplateArgs(),
                                  TemplateArgs, Info, Deduced))
  return Result;

SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
                           Info);
if (Inst.isInvalid())
  return TDK_InstantiationDepth;

if (Trap.hasErrorOccurred())
  return Sema::TDK_SubstitutionFailure;

return ::FinishTemplateArgumentDeduction(
    *this, Partial, /*IsPartialOrdering=*/false, TemplateArgs, Deduced, Info);
2876}

2878/// Perform template argument deduction to determine whether
2879/// the given template arguments match the given variable template
2880/// partial specialization per C++ [temp.class.spec.match].
2881Sema::TemplateDeductionResult
2882Sema::DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
                            const TemplateArgumentList &TemplateArgs,
                            TemplateDeductionInfo &Info) {
if (Partial->isInvalidDecl())
  return TDK_Invalid;

// C++ [temp.class.spec.match]p2:
//   A partial specialization matches a given actual template
//   argument list if the template arguments of the partial
//   specialization can be deduced from the actual template argument
//   list (14.8.2).

// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);
SFINAETrap Trap(*this);

SmallVector<DeducedTemplateArgument, 4> Deduced;
Deduced.resize(Partial->getTemplateParameters()->size());
if (TemplateDeductionResult Result = ::DeduceTemplateArguments(
        *this, Partial->getTemplateParameters(), Partial->getTemplateArgs(),
        TemplateArgs, Info, Deduced))
  return Result;

SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
                           Info);
if (Inst.isInvalid())
  return TDK_InstantiationDepth;

if (Trap.hasErrorOccurred())
  return Sema::TDK_SubstitutionFailure;

return ::FinishTemplateArgumentDeduction(
    *this, Partial, /*IsPartialOrdering=*/false, TemplateArgs, Deduced, Info);
2917}

2919/// Determine whether the given type T is a simple-template-id type.
2920static bool isSimpleTemplateIdType(QualType T) {
if (const TemplateSpecializationType *Spec
      = T->getAs<TemplateSpecializationType>())
  return Spec->getTemplateName().getAsTemplateDecl() != nullptr;

// C++17 [temp.local]p2:
//   the injected-class-name [...] is equivalent to the template-name followed
//   by the template-arguments of the class template specialization or partial
//   specialization enclosed in <>
// ... which means it's equivalent to a simple-template-id.
//
// This only arises during class template argument deduction for a copy
// deduction candidate, where it permits slicing.
if (T->getAs<InjectedClassNameType>())
  return true;

return false;
2937}

2939/// Substitute the explicitly-provided template arguments into the
2940/// given function template according to C++ [temp.arg.explicit].
2941///
2942/// \param FunctionTemplate the function template into which the explicit
2943/// template arguments will be substituted.
2944///
2945/// \param ExplicitTemplateArgs the explicitly-specified template
2946/// arguments.
2947///
2948/// \param Deduced the deduced template arguments, which will be populated
2949/// with the converted and checked explicit template arguments.
2950///
2951/// \param ParamTypes will be populated with the instantiated function
2952/// parameters.
2953///
2954/// \param FunctionType if non-NULL, the result type of the function template
2955/// will also be instantiated and the pointed-to value will be updated with
2956/// the instantiated function type.
2957///
2958/// \param Info if substitution fails for any reason, this object will be
2959/// populated with more information about the failure.
2960///
2961/// \returns TDK_Success if substitution was successful, or some failure
2962/// condition.
2963Sema::TemplateDeductionResult
2964Sema::SubstituteExplicitTemplateArguments(
                                    FunctionTemplateDecl *FunctionTemplate,
                             TemplateArgumentListInfo &ExplicitTemplateArgs,
                     SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                               SmallVectorImpl<QualType> &ParamTypes,
                                        QualType *FunctionType,
                                        TemplateDeductionInfo &Info) {
FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
TemplateParameterList *TemplateParams
  = FunctionTemplate->getTemplateParameters();

if (ExplicitTemplateArgs.size() == 0) {
  // No arguments to substitute; just copy over the parameter types and
  // fill in the function type.
  for (auto P : Function->parameters())
    ParamTypes.push_back(P->getType());

  if (FunctionType)
    *FunctionType = Function->getType();
  return TDK_Success;
}

// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);
SFINAETrap Trap(*this);

// C++ [temp.arg.explicit]p3:
//   Template arguments that are present shall be specified in the
//   declaration order of their corresponding template-parameters. The
//   template argument list shall not specify more template-arguments than
//   there are corresponding template-parameters.
SmallVector<TemplateArgument, 4> Builder;

// Enter a new template instantiation context where we check the
// explicitly-specified template arguments against this function template,
// and then substitute them into the function parameter types.
SmallVector<TemplateArgument, 4> DeducedArgs;
InstantiatingTemplate Inst(
    *this, Info.getLocation(), FunctionTemplate, DeducedArgs,
    CodeSynthesisContext::ExplicitTemplateArgumentSubstitution, Info);
if (Inst.isInvalid())
  return TDK_InstantiationDepth;

if (CheckTemplateArgumentList(FunctionTemplate, SourceLocation(),
                              ExplicitTemplateArgs, true, Builder, false) ||
    Trap.hasErrorOccurred()) {
  unsigned Index = Builder.size();
  if (Index >= TemplateParams->size())
    return TDK_SubstitutionFailure;
  Info.Param = makeTemplateParameter(TemplateParams->getParam(Index));
  return TDK_InvalidExplicitArguments;
}

// Form the template argument list from the explicitly-specified
// template arguments.
TemplateArgumentList *ExplicitArgumentList
  = TemplateArgumentList::CreateCopy(Context, Builder);
Info.setExplicitArgs(ExplicitArgumentList);

// Template argument deduction and the final substitution should be
// done in the context of the templated declaration.  Explicit
// argument substitution, on the other hand, needs to happen in the
// calling context.
ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());

// If we deduced template arguments for a template parameter pack,
// note that the template argument pack is partially substituted and record
// the explicit template arguments. They'll be used as part of deduction
// for this template parameter pack.
unsigned PartiallySubstitutedPackIndex = -1u;
if (!Builder.empty()) {
  const TemplateArgument &Arg = Builder.back();
  if (Arg.getKind() == TemplateArgument::Pack) {
    auto *Param = TemplateParams->getParam(Builder.size() - 1);
    // If this is a fully-saturated fixed-size pack, it should be
    // fully-substituted, not partially-substituted.
    Optional<unsigned> Expansions = getExpandedPackSize(Param);
    if (!Expansions || Arg.pack_size() < *Expansions) {
      PartiallySubstitutedPackIndex = Builder.size() - 1;
      CurrentInstantiationScope->SetPartiallySubstitutedPack(
          Param, Arg.pack_begin(), Arg.pack_size());
    }
  }
}

const FunctionProtoType *Proto
  = Function->getType()->getAs<FunctionProtoType>();
assert(Proto && "Function template does not have a prototype?")((Proto && "Function template does not have a prototype?"
) ? static_cast<void> (0) : __assert_fail ("Proto && \"Function template does not have a prototype?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3052, __PRETTY_FUNCTION__));

// Isolate our substituted parameters from our caller.
LocalInstantiationScope InstScope(*this, /*MergeWithOuterScope*/true);

ExtParameterInfoBuilder ExtParamInfos;

// Instantiate the types of each of the function parameters given the
// explicitly-specified template arguments. If the function has a trailing
// return type, substitute it after the arguments to ensure we substitute
// in lexical order.
if (Proto->hasTrailingReturn()) {
  if (SubstParmTypes(Function->getLocation(), Function->parameters(),
                     Proto->getExtParameterInfosOrNull(),
                     MultiLevelTemplateArgumentList(*ExplicitArgumentList),
                     ParamTypes, /*params*/ nullptr, ExtParamInfos))
    return TDK_SubstitutionFailure;
}

// Instantiate the return type.
QualType ResultType;
{
  // C++11 [expr.prim.general]p3:
  //   If a declaration declares a member function or member function
  //   template of a class X, the expression this is a prvalue of type
  //   "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
  //   and the end of the function-definition, member-declarator, or
  //   declarator.
  Qualifiers ThisTypeQuals;
  CXXRecordDecl *ThisContext = nullptr;
  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
    ThisContext = Method->getParent();
    ThisTypeQuals = Method->getMethodQualifiers();
  }

  CXXThisScopeRAII ThisScope(*this, ThisContext, ThisTypeQuals,
                             getLangOpts().CPlusPlus11);

  ResultType =
      SubstType(Proto->getReturnType(),
                MultiLevelTemplateArgumentList(*ExplicitArgumentList),
                Function->getTypeSpecStartLoc(), Function->getDeclName());
  if (ResultType.isNull() || Trap.hasErrorOccurred())
    return TDK_SubstitutionFailure;
  // CUDA: Kernel function must have 'void' return type.
  if (getLangOpts().CUDA)
    if (Function->hasAttr<CUDAGlobalAttr>() && !ResultType->isVoidType()) {
      Diag(Function->getLocation(), diag::err_kern_type_not_void_return)
          << Function->getType() << Function->getSourceRange();
      return TDK_SubstitutionFailure;
    }
}

// Instantiate the types of each of the function parameters given the
// explicitly-specified template arguments if we didn't do so earlier.
if (!Proto->hasTrailingReturn() &&
    SubstParmTypes(Function->getLocation(), Function->parameters(),
                   Proto->getExtParameterInfosOrNull(),
                   MultiLevelTemplateArgumentList(*ExplicitArgumentList),
                   ParamTypes, /*params*/ nullptr, ExtParamInfos))
  return TDK_SubstitutionFailure;

if (FunctionType) {
  auto EPI = Proto->getExtProtoInfo();
  EPI.ExtParameterInfos = ExtParamInfos.getPointerOrNull(ParamTypes.size());

  // In C++1z onwards, exception specifications are part of the function type,
  // so substitution into the type must also substitute into the exception
  // specification.
  SmallVector<QualType, 4> ExceptionStorage;
  if (getLangOpts().CPlusPlus17 &&
      SubstExceptionSpec(
          Function->getLocation(), EPI.ExceptionSpec, ExceptionStorage,
          MultiLevelTemplateArgumentList(*ExplicitArgumentList)))
    return TDK_SubstitutionFailure;

  *FunctionType = BuildFunctionType(ResultType, ParamTypes,
                                    Function->getLocation(),
                                    Function->getDeclName(),
                                    EPI);
  if (FunctionType->isNull() || Trap.hasErrorOccurred())
    return TDK_SubstitutionFailure;
}

// C++ [temp.arg.explicit]p2:
//   Trailing template arguments that can be deduced (14.8.2) may be
//   omitted from the list of explicit template-arguments. If all of the
//   template arguments can be deduced, they may all be omitted; in this
//   case, the empty template argument list <> itself may also be omitted.
//
// Take all of the explicitly-specified arguments and put them into
// the set of deduced template arguments. The partially-substituted
// parameter pack, however, will be set to NULL since the deduction
// mechanism handles the partially-substituted argument pack directly.
Deduced.reserve(TemplateParams->size());
for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) {
  const TemplateArgument &Arg = ExplicitArgumentList->get(I);
  if (I == PartiallySubstitutedPackIndex)
    Deduced.push_back(DeducedTemplateArgument());
  else
    Deduced.push_back(Arg);
}

return TDK_Success;
3156}

3158/// Check whether the deduced argument type for a call to a function
3159/// template matches the actual argument type per C++ [temp.deduct.call]p4.
3160static Sema::TemplateDeductionResult
3161CheckOriginalCallArgDeduction(Sema &S, TemplateDeductionInfo &Info,
                            Sema::OriginalCallArg OriginalArg,
                            QualType DeducedA) {
ASTContext &Context = S.Context;

auto Failed = [&]() -> Sema::TemplateDeductionResult {
  Info.FirstArg = TemplateArgument(DeducedA);
  Info.SecondArg = TemplateArgument(OriginalArg.OriginalArgType);
  Info.CallArgIndex = OriginalArg.ArgIdx;
  return OriginalArg.DecomposedParam ? Sema::TDK_DeducedMismatchNested
                                     : Sema::TDK_DeducedMismatch;
};

QualType A = OriginalArg.OriginalArgType;
QualType OriginalParamType = OriginalArg.OriginalParamType;

// Check for type equality (top-level cv-qualifiers are ignored).
if (Context.hasSameUnqualifiedType(A, DeducedA))
  return Sema::TDK_Success;

// Strip off references on the argument types; they aren't needed for
// the following checks.
if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>())
  DeducedA = DeducedARef->getPointeeType();
if (const ReferenceType *ARef = A->getAs<ReferenceType>())
  A = ARef->getPointeeType();

// C++ [temp.deduct.call]p4:
//   [...] However, there are three cases that allow a difference:
//     - If the original P is a reference type, the deduced A (i.e., the
//       type referred to by the reference) can be more cv-qualified than
//       the transformed A.
if (const ReferenceType *OriginalParamRef
    = OriginalParamType->getAs<ReferenceType>()) {
  // We don't want to keep the reference around any more.
  OriginalParamType = OriginalParamRef->getPointeeType();

  // FIXME: Resolve core issue (no number yet): if the original P is a
  // reference type and the transformed A is function type "noexcept F",
  // the deduced A can be F.
  QualType Tmp;
  if (A->isFunctionType() && S.IsFunctionConversion(A, DeducedA, Tmp))
    return Sema::TDK_Success;

  Qualifiers AQuals = A.getQualifiers();
  Qualifiers DeducedAQuals = DeducedA.getQualifiers();

  // Under Objective-C++ ARC, the deduced type may have implicitly
  // been given strong or (when dealing with a const reference)
  // unsafe_unretained lifetime. If so, update the original
  // qualifiers to include this lifetime.
  if (S.getLangOpts().ObjCAutoRefCount &&
      ((DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_Strong &&
        AQuals.getObjCLifetime() == Qualifiers::OCL_None) ||
       (DeducedAQuals.hasConst() &&
        DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone))) {
    AQuals.setObjCLifetime(DeducedAQuals.getObjCLifetime());
  }

  if (AQuals == DeducedAQuals) {
    // Qualifiers match; there's nothing to do.
  } else if (!DeducedAQuals.compatiblyIncludes(AQuals)) {
    return Failed();
  } else {
    // Qualifiers are compatible, so have the argument type adopt the
    // deduced argument type's qualifiers as if we had performed the
    // qualification conversion.
    A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals);
  }
}

//    - The transformed A can be another pointer or pointer to member
//      type that can be converted to the deduced A via a function pointer
//      conversion and/or a qualification conversion.
//
// Also allow conversions which merely strip __attribute__((noreturn)) from
// function types (recursively).
bool ObjCLifetimeConversion = false;
QualType ResultTy;
if ((A->isAnyPointerType() || A->isMemberPointerType()) &&
    (S.IsQualificationConversion(A, DeducedA, false,
                                 ObjCLifetimeConversion) ||
     S.IsFunctionConversion(A, DeducedA, ResultTy)))
  return Sema::TDK_Success;

//    - If P is a class and P has the form simple-template-id, then the
//      transformed A can be a derived class of the deduced A. [...]
//     [...] Likewise, if P is a pointer to a class of the form
//      simple-template-id, the transformed A can be a pointer to a
//      derived class pointed to by the deduced A.
if (const PointerType *OriginalParamPtr
    = OriginalParamType->getAs<PointerType>()) {
  if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) {
    if (const PointerType *APtr = A->getAs<PointerType>()) {
      if (A->getPointeeType()->isRecordType()) {
        OriginalParamType = OriginalParamPtr->getPointeeType();
        DeducedA = DeducedAPtr->getPointeeType();
        A = APtr->getPointeeType();
      }
    }
  }
}

if (Context.hasSameUnqualifiedType(A, DeducedA))
  return Sema::TDK_Success;

if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) &&
    S.IsDerivedFrom(Info.getLocation(), A, DeducedA))
  return Sema::TDK_Success;

return Failed();
3272}

3274/// Find the pack index for a particular parameter index in an instantiation of
3275/// a function template with specific arguments.
3276///
3277/// \return The pack index for whichever pack produced this parameter, or -1
3278///         if this was not produced by a parameter. Intended to be used as the
3279///         ArgumentPackSubstitutionIndex for further substitutions.
3280// FIXME: We should track this in OriginalCallArgs so we don't need to
3281// reconstruct it here.
3282static unsigned getPackIndexForParam(Sema &S,
                                   FunctionTemplateDecl *FunctionTemplate,
                                   const MultiLevelTemplateArgumentList &Args,
                                   unsigned ParamIdx) {
unsigned Idx = 0;
for (auto *PD : FunctionTemplate->getTemplatedDecl()->parameters()) {
  if (PD->isParameterPack()) {
    unsigned NumExpansions =
        S.getNumArgumentsInExpansion(PD->getType(), Args).getValueOr(1);
    if (Idx + NumExpansions > ParamIdx)
      return ParamIdx - Idx;
    Idx += NumExpansions;
  } else {
    if (Idx == ParamIdx)
      return -1; // Not a pack expansion
    ++Idx;
  }
}

llvm_unreachable("parameter index would not be produced from template")::llvm::llvm_unreachable_internal("parameter index would not be produced from template"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3301);
3302}

3304/// Finish template argument deduction for a function template,
3305/// checking the deduced template arguments for completeness and forming
3306/// the function template specialization.
3307///
3308/// \param OriginalCallArgs If non-NULL, the original call arguments against
3309/// which the deduced argument types should be compared.
3310Sema::TemplateDeductionResult Sema::FinishTemplateArgumentDeduction(
  FunctionTemplateDecl *FunctionTemplate,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced,
  unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
  TemplateDeductionInfo &Info,
  SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs,
  bool PartialOverloading, llvm::function_ref<bool()> CheckNonDependent) {
// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);
SFINAETrap Trap(*this);

// Enter a new template instantiation context while we instantiate the
// actual function declaration.
SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
InstantiatingTemplate Inst(
    *this, Info.getLocation(), FunctionTemplate, DeducedArgs,
    CodeSynthesisContext::DeducedTemplateArgumentSubstitution, Info);
if (Inst.isInvalid())
  return TDK_InstantiationDepth;

ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());

// C++ [temp.deduct.type]p2:
//   [...] or if any template argument remains neither deduced nor
//   explicitly specified, template argument deduction fails.
SmallVector<TemplateArgument, 4> Builder;
if (auto Result = ConvertDeducedTemplateArguments(
        *this, FunctionTemplate, /*IsDeduced*/true, Deduced, Info, Builder,
        CurrentInstantiationScope, NumExplicitlySpecified,
        PartialOverloading))
  return Result;

// C++ [temp.deduct.call]p10: [DR1391]
//   If deduction succeeds for all parameters that contain
//   template-parameters that participate in template argument deduction,
//   and all template arguments are explicitly specified, deduced, or
//   obtained from default template arguments, remaining parameters are then
//   compared with the corresponding arguments. For each remaining parameter
//   P with a type that was non-dependent before substitution of any
//   explicitly-specified template arguments, if the corresponding argument
//   A cannot be implicitly converted to P, deduction fails.
if (CheckNonDependent())
  return TDK_NonDependentConversionFailure;

// Form the template argument list from the deduced template arguments.
TemplateArgumentList *DeducedArgumentList
  = TemplateArgumentList::CreateCopy(Context, Builder);
Info.reset(DeducedArgumentList);

// Substitute the deduced template arguments into the function template
// declaration to produce the function template specialization.
DeclContext *Owner = FunctionTemplate->getDeclContext();
if (FunctionTemplate->getFriendObjectKind())
  Owner = FunctionTemplate->getLexicalDeclContext();
MultiLevelTemplateArgumentList SubstArgs(*DeducedArgumentList);
Specialization = cast_or_null<FunctionDecl>(
    SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, SubstArgs));
if (!Specialization || Specialization->isInvalidDecl())
  return TDK_SubstitutionFailure;

assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() ==((Specialization->getPrimaryTemplate()->getCanonicalDecl
() == FunctionTemplate->getCanonicalDecl()) ? static_cast<
void> (0) : __assert_fail ("Specialization->getPrimaryTemplate()->getCanonicalDecl() == FunctionTemplate->getCanonicalDecl()"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3372, __PRETTY_FUNCTION__))
       FunctionTemplate->getCanonicalDecl())((Specialization->getPrimaryTemplate()->getCanonicalDecl
() == FunctionTemplate->getCanonicalDecl()) ? static_cast<
void> (0) : __assert_fail ("Specialization->getPrimaryTemplate()->getCanonicalDecl() == FunctionTemplate->getCanonicalDecl()"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3372, __PRETTY_FUNCTION__));

// If the template argument list is owned by the function template
// specialization, release it.
if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList &&
    !Trap.hasErrorOccurred())
  Info.take();

// There may have been an error that did not prevent us from constructing a
// declaration. Mark the declaration invalid and return with a substitution
// failure.
if (Trap.hasErrorOccurred()) {
  Specialization->setInvalidDecl(true);
  return TDK_SubstitutionFailure;
}

if (OriginalCallArgs) {
  // C++ [temp.deduct.call]p4:
  //   In general, the deduction process attempts to find template argument
  //   values that will make the deduced A identical to A (after the type A
  //   is transformed as described above). [...]
  llvm::SmallDenseMap<std::pair<unsigned, QualType>, QualType> DeducedATypes;
  for (unsigned I = 0, N = OriginalCallArgs->size(); I != N; ++I) {
    OriginalCallArg OriginalArg = (*OriginalCallArgs)[I];

    auto ParamIdx = OriginalArg.ArgIdx;
    if (ParamIdx >= Specialization->getNumParams())
      // FIXME: This presumably means a pack ended up smaller than we
      // expected while deducing. Should this not result in deduction
      // failure? Can it even happen?
      continue;

    QualType DeducedA;
    if (!OriginalArg.DecomposedParam) {
      // P is one of the function parameters, just look up its substituted
      // type.
      DeducedA = Specialization->getParamDecl(ParamIdx)->getType();
    } else {
      // P is a decomposed element of a parameter corresponding to a
      // braced-init-list argument. Substitute back into P to find the
      // deduced A.
      QualType &CacheEntry =
          DeducedATypes[{ParamIdx, OriginalArg.OriginalParamType}];
      if (CacheEntry.isNull()) {
        ArgumentPackSubstitutionIndexRAII PackIndex(
            *this, getPackIndexForParam(*this, FunctionTemplate, SubstArgs,
                                        ParamIdx));
        CacheEntry =
            SubstType(OriginalArg.OriginalParamType, SubstArgs,
                      Specialization->getTypeSpecStartLoc(),
                      Specialization->getDeclName());
      }
      DeducedA = CacheEntry;
    }

    if (auto TDK =
            CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA))
      return TDK;
  }
}

// If we suppressed any diagnostics while performing template argument
// deduction, and if we haven't already instantiated this declaration,
// keep track of these diagnostics. They'll be emitted if this specialization
// is actually used.
if (Info.diag_begin() != Info.diag_end()) {
  SuppressedDiagnosticsMap::iterator
    Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl());
  if (Pos == SuppressedDiagnostics.end())
      SuppressedDiagnostics[Specialization->getCanonicalDecl()]
        .append(Info.diag_begin(), Info.diag_end());
}

return TDK_Success;
3446}

3448/// Gets the type of a function for template-argument-deducton
3449/// purposes when it's considered as part of an overload set.
3450static QualType GetTypeOfFunction(Sema &S, const OverloadExpr::FindResult &R,
                                FunctionDecl *Fn) {
// We may need to deduce the return type of the function now.
if (S.getLangOpts().CPlusPlus14 && Fn->getReturnType()->isUndeducedType() &&
    S.DeduceReturnType(Fn, R.Expression->getExprLoc(), /*Diagnose*/ false))
  return {};

if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
  if (Method->isInstance()) {
    // An instance method that's referenced in a form that doesn't
    // look like a member pointer is just invalid.
    if (!R.HasFormOfMemberPointer)
      return {};

    return S.Context.getMemberPointerType(Fn->getType(),
             S.Context.getTypeDeclType(Method->getParent()).getTypePtr());
  }

if (!R.IsAddressOfOperand) return Fn->getType();
return S.Context.getPointerType(Fn->getType());
3470}

3472/// Apply the deduction rules for overload sets.
3473///
3474/// \return the null type if this argument should be treated as an
3475/// undeduced context
3476static QualType
3477ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams,
                          Expr *Arg, QualType ParamType,
                          bool ParamWasReference) {

OverloadExpr::FindResult R = OverloadExpr::find(Arg);

OverloadExpr *Ovl = R.Expression;

// C++0x [temp.deduct.call]p4
unsigned TDF = 0;
if (ParamWasReference)
  TDF |= TDF_ParamWithReferenceType;
if (R.IsAddressOfOperand)
  TDF |= TDF_IgnoreQualifiers;

// C++0x [temp.deduct.call]p6:
//   When P is a function type, pointer to function type, or pointer
//   to member function type:

if (!ParamType->isFunctionType() &&
    !ParamType->isFunctionPointerType() &&
    !ParamType->isMemberFunctionPointerType()) {
  if (Ovl->hasExplicitTemplateArgs()) {
    // But we can still look for an explicit specialization.
    if (FunctionDecl *ExplicitSpec
          = S.ResolveSingleFunctionTemplateSpecialization(Ovl))
      return GetTypeOfFunction(S, R, ExplicitSpec);
  }

  DeclAccessPair DAP;
  if (FunctionDecl *Viable =
          S.resolveAddressOfOnlyViableOverloadCandidate(Arg, DAP))
    return GetTypeOfFunction(S, R, Viable);

  return {};
}

// Gather the explicit template arguments, if any.
TemplateArgumentListInfo ExplicitTemplateArgs;
if (Ovl->hasExplicitTemplateArgs())
  Ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
QualType Match;
for (UnresolvedSetIterator I = Ovl->decls_begin(),
       E = Ovl->decls_end(); I != E; ++I) {
  NamedDecl *D = (*I)->getUnderlyingDecl();

  if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) {
    //   - If the argument is an overload set containing one or more
    //     function templates, the parameter is treated as a
    //     non-deduced context.
    if (!Ovl->hasExplicitTemplateArgs())
      return {};

    // Otherwise, see if we can resolve a function type
    FunctionDecl *Specialization = nullptr;
    TemplateDeductionInfo Info(Ovl->getNameLoc());
    if (S.DeduceTemplateArguments(FunTmpl, &ExplicitTemplateArgs,
                                  Specialization, Info))
      continue;

    D = Specialization;
  }

  FunctionDecl *Fn = cast<FunctionDecl>(D);
  QualType ArgType = GetTypeOfFunction(S, R, Fn);
  if (ArgType.isNull()) continue;

  // Function-to-pointer conversion.
  if (!ParamWasReference && ParamType->isPointerType() &&
      ArgType->isFunctionType())
    ArgType = S.Context.getPointerType(ArgType);

  //   - If the argument is an overload set (not containing function
  //     templates), trial argument deduction is attempted using each
  //     of the members of the set. If deduction succeeds for only one
  //     of the overload set members, that member is used as the
  //     argument value for the deduction. If deduction succeeds for
  //     more than one member of the overload set the parameter is
  //     treated as a non-deduced context.

  // We do all of this in a fresh context per C++0x [temp.deduct.type]p2:
  //   Type deduction is done independently for each P/A pair, and
  //   the deduced template argument values are then combined.
  // So we do not reject deductions which were made elsewhere.
  SmallVector<DeducedTemplateArgument, 8>
    Deduced(TemplateParams->size());
  TemplateDeductionInfo Info(Ovl->getNameLoc());
  Sema::TemplateDeductionResult Result
    = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
                                         ArgType, Info, Deduced, TDF);
  if (Result) continue;
  if (!Match.isNull())
    return {};
  Match = ArgType;
}

return Match;
3574}

3576/// Perform the adjustments to the parameter and argument types
3577/// described in C++ [temp.deduct.call].
3578///
3579/// \returns true if the caller should not attempt to perform any template
3580/// argument deduction based on this P/A pair because the argument is an
3581/// overloaded function set that could not be resolved.
3582static bool AdjustFunctionParmAndArgTypesForDeduction(
  Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
  QualType &ParamType, QualType &ArgType, Expr *Arg, unsigned &TDF) {
// C++0x [temp.deduct.call]p3:
//   If P is a cv-qualified type, the top level cv-qualifiers of P's type
//   are ignored for type deduction.
if (ParamType.hasQualifiers())
  ParamType = ParamType.getUnqualifiedType();

//   [...] If P is a reference type, the type referred to by P is
//   used for type deduction.
const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>();
if (ParamRefType)
  ParamType = ParamRefType->getPointeeType();

// Overload sets usually make this parameter an undeduced context,
// but there are sometimes special circumstances.  Typically
// involving a template-id-expr.
if (ArgType == S.Context.OverloadTy) {
  ArgType = ResolveOverloadForDeduction(S, TemplateParams,
                                        Arg, ParamType,
                                        ParamRefType != nullptr);
  if (ArgType.isNull())
    return true;
}

if (ParamRefType) {
  // If the argument has incomplete array type, try to complete its type.
  if (ArgType->isIncompleteArrayType()) {
    S.completeExprArrayBound(Arg);
    ArgType = Arg->getType();
  }

  // C++1z [temp.deduct.call]p3:
  //   If P is a forwarding reference and the argument is an lvalue, the type
  //   "lvalue reference to A" is used in place of A for type deduction.
  if (isForwardingReference(QualType(ParamRefType, 0), FirstInnerIndex) &&
      Arg->isLValue())
    ArgType = S.Context.getLValueReferenceType(ArgType);
} else {
  // C++ [temp.deduct.call]p2:
  //   If P is not a reference type:
  //   - If A is an array type, the pointer type produced by the
  //     array-to-pointer standard conversion (4.2) is used in place of
  //     A for type deduction; otherwise,
  if (ArgType->isArrayType())
    ArgType = S.Context.getArrayDecayedType(ArgType);
  //   - If A is a function type, the pointer type produced by the
  //     function-to-pointer standard conversion (4.3) is used in place
  //     of A for type deduction; otherwise,
  else if (ArgType->isFunctionType())
    ArgType = S.Context.getPointerType(ArgType);
  else {
    // - If A is a cv-qualified type, the top level cv-qualifiers of A's
    //   type are ignored for type deduction.
    ArgType = ArgType.getUnqualifiedType();
  }
}

// C++0x [temp.deduct.call]p4:
//   In general, the deduction process attempts to find template argument
//   values that will make the deduced A identical to A (after the type A
//   is transformed as described above). [...]
TDF = TDF_SkipNonDependent;

//     - If the original P is a reference type, the deduced A (i.e., the
//       type referred to by the reference) can be more cv-qualified than
//       the transformed A.
if (ParamRefType)
  TDF |= TDF_ParamWithReferenceType;
//     - The transformed A can be another pointer or pointer to member
//       type that can be converted to the deduced A via a qualification
//       conversion (4.4).
if (ArgType->isPointerType() || ArgType->isMemberPointerType() ||
    ArgType->isObjCObjectPointerType())
  TDF |= TDF_IgnoreQualifiers;
//     - If P is a class and P has the form simple-template-id, then the
//       transformed A can be a derived class of the deduced A. Likewise,
//       if P is a pointer to a class of the form simple-template-id, the
//       transformed A can be a pointer to a derived class pointed to by
//       the deduced A.
if (isSimpleTemplateIdType(ParamType) ||
    (isa<PointerType>(ParamType) &&
     isSimpleTemplateIdType(
                            ParamType->getAs<PointerType>()->getPointeeType())))
  TDF |= TDF_DerivedClass;

return false;
3670}

3672static bool
3673hasDeducibleTemplateParameters(Sema &S, FunctionTemplateDecl *FunctionTemplate,
                             QualType T);

3676static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument(
  Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
  QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced,
  SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs,
  bool DecomposedParam, unsigned ArgIdx, unsigned TDF);

3683/// Attempt template argument deduction from an initializer list
3684///        deemed to be an argument in a function call.
3685static Sema::TemplateDeductionResult DeduceFromInitializerList(
  Sema &S, TemplateParameterList *TemplateParams, QualType AdjustedParamType,
  InitListExpr *ILE, TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced,
  SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs, unsigned ArgIdx,
  unsigned TDF) {
// C++ [temp.deduct.call]p1: (CWG 1591)
//   If removing references and cv-qualifiers from P gives
//   std::initializer_list<P0> or P0[N] for some P0 and N and the argument is
//   a non-empty initializer list, then deduction is performed instead for
//   each element of the initializer list, taking P0 as a function template
//   parameter type and the initializer element as its argument
//
// We've already removed references and cv-qualifiers here.
if (!ILE->getNumInits())
  return Sema::TDK_Success;

QualType ElTy;
auto *ArrTy = S.Context.getAsArrayType(AdjustedParamType);
if (ArrTy)
  ElTy = ArrTy->getElementType();
else if (!S.isStdInitializerList(AdjustedParamType, &ElTy)) {
  //   Otherwise, an initializer list argument causes the parameter to be
  //   considered a non-deduced context
  return Sema::TDK_Success;
}

// Resolving a core issue: a braced-init-list containing any designators is
// a non-deduced context.
for (Expr *E : ILE->inits())
  if (isa<DesignatedInitExpr>(E))
    return Sema::TDK_Success;

// Deduction only needs to be done for dependent types.
if (ElTy->isDependentType()) {
  for (Expr *E : ILE->inits()) {
    if (auto Result = DeduceTemplateArgumentsFromCallArgument(
            S, TemplateParams, 0, ElTy, E, Info, Deduced, OriginalCallArgs, true,
            ArgIdx, TDF))
      return Result;
  }
}

//   in the P0[N] case, if N is a non-type template parameter, N is deduced
//   from the length of the initializer list.
if (auto *DependentArrTy = dyn_cast_or_null<DependentSizedArrayType>(ArrTy)) {
  // Determine the array bound is something we can deduce.
  if (NonTypeTemplateParmDecl *NTTP =
          getDeducedParameterFromExpr(Info, DependentArrTy->getSizeExpr())) {
    // We can perform template argument deduction for the given non-type
    // template parameter.
    // C++ [temp.deduct.type]p13:
    //   The type of N in the type T[N] is std::size_t.
    QualType T = S.Context.getSizeType();
    llvm::APInt Size(S.Context.getIntWidth(T), ILE->getNumInits());
    if (auto Result = DeduceNonTypeTemplateArgument(
            S, TemplateParams, NTTP, llvm::APSInt(Size), T,
            /*ArrayBound=*/true, Info, Deduced))
      return Result;
  }
}

return Sema::TDK_Success;
3748}

3750/// Perform template argument deduction per [temp.deduct.call] for a
3751///        single parameter / argument pair.
3752static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument(
  Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
  QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info,
  SmallVectorImpl<DeducedTemplateArgument> &Deduced,
  SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs,
  bool DecomposedParam, unsigned ArgIdx, unsigned TDF) {
QualType ArgType = Arg->getType();
QualType OrigParamType = ParamType;

//   If P is a reference type [...]
//   If P is a cv-qualified type [...]
if (AdjustFunctionParmAndArgTypesForDeduction(
        S, TemplateParams, FirstInnerIndex, ParamType, ArgType, Arg, TDF))
  return Sema::TDK_Success;

//   If [...] the argument is a non-empty initializer list [...]
if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg))
  return DeduceFromInitializerList(S, TemplateParams, ParamType, ILE, Info,
                                   Deduced, OriginalCallArgs, ArgIdx, TDF);

//   [...] the deduction process attempts to find template argument values
//   that will make the deduced A identical to A
//
// Keep track of the argument type and corresponding parameter index,
// so we can check for compatibility between the deduced A and A.
OriginalCallArgs.push_back(
    Sema::OriginalCallArg(OrigParamType, DecomposedParam, ArgIdx, ArgType));
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
                                          ArgType, Info, Deduced, TDF);
3781}

3783/// Perform template argument deduction from a function call
3784/// (C++ [temp.deduct.call]).
3785///
3786/// \param FunctionTemplate the function template for which we are performing
3787/// template argument deduction.
3788///
3789/// \param ExplicitTemplateArgs the explicit template arguments provided
3790/// for this call.
3791///
3792/// \param Args the function call arguments
3793///
3794/// \param Specialization if template argument deduction was successful,
3795/// this will be set to the function template specialization produced by
3796/// template argument deduction.
3797///
3798/// \param Info the argument will be updated to provide additional information
3799/// about template argument deduction.
3800///
3801/// \param CheckNonDependent A callback to invoke to check conversions for
3802/// non-dependent parameters, between deduction and substitution, per DR1391.
3803/// If this returns true, substitution will be skipped and we return
3804/// TDK_NonDependentConversionFailure. The callback is passed the parameter
3805/// types (after substituting explicit template arguments).
3806///
3807/// \returns the result of template argument deduction.
3808Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
  FunctionTemplateDecl *FunctionTemplate,
  TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
  FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
  bool PartialOverloading,
  llvm::function_ref<bool(ArrayRef<QualType>)> CheckNonDependent) {
if (FunctionTemplate->isInvalidDecl())
1
Assuming the condition is false→
2
←
Taking false branch→
  return TDK_Invalid;

FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
unsigned NumParams = Function->getNumParams();

unsigned FirstInnerIndex = getFirstInnerIndex(FunctionTemplate);

// C++ [temp.deduct.call]p1:
//   Template argument deduction is done by comparing each function template
//   parameter type (call it P) with the type of the corresponding argument
//   of the call (call it A) as described below.
if (Args.size() < Function->getMinRequiredArguments() && !PartialOverloading)
3
←
Assuming the condition is false→
  return TDK_TooFewArguments;
else if (TooManyArguments(NumParams, Args.size(), PartialOverloading)) {
4
←
Calling 'Sema::TooManyArguments'→
10
←
Returning from 'Sema::TooManyArguments'→
11
←
Taking true branch→
  const FunctionProtoType *Proto
13
←
'Proto' initialized to a null pointer value→
    = Function->getType()->getAs<FunctionProtoType>();
12
←
Assuming the object is not a 'FunctionProtoType'→
  if (Proto->isTemplateVariadic())
14
←
Called C++ object pointer is null
    /* Do nothing */;
  else if (!Proto->isVariadic())
    return TDK_TooManyArguments;
}

// The types of the parameters from which we will perform template argument
// deduction.
LocalInstantiationScope InstScope(*this);
TemplateParameterList *TemplateParams
  = FunctionTemplate->getTemplateParameters();
SmallVector<DeducedTemplateArgument, 4> Deduced;
SmallVector<QualType, 8> ParamTypes;
unsigned NumExplicitlySpecified = 0;
if (ExplicitTemplateArgs) {
  TemplateDeductionResult Result =
    SubstituteExplicitTemplateArguments(FunctionTemplate,
                                        *ExplicitTemplateArgs,
                                        Deduced,
                                        ParamTypes,
                                        nullptr,
                                        Info);
  if (Result)
    return Result;

  NumExplicitlySpecified = Deduced.size();
} else {
  // Just fill in the parameter types from the function declaration.
  for (unsigned I = 0; I != NumParams; ++I)
    ParamTypes.push_back(Function->getParamDecl(I)->getType());
}

SmallVector<OriginalCallArg, 8> OriginalCallArgs;

// Deduce an argument of type ParamType from an expression with index ArgIdx.
auto DeduceCallArgument = [&](QualType ParamType, unsigned ArgIdx) {
  // C++ [demp.deduct.call]p1: (DR1391)
  //   Template argument deduction is done by comparing each function template
  //   parameter that contains template-parameters that participate in
  //   template argument deduction ...
  if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType))
    return Sema::TDK_Success;

  //   ... with the type of the corresponding argument
  return DeduceTemplateArgumentsFromCallArgument(
      *this, TemplateParams, FirstInnerIndex, ParamType, Args[ArgIdx], Info, Deduced,
      OriginalCallArgs, /*Decomposed*/false, ArgIdx, /*TDF*/ 0);
};

// Deduce template arguments from the function parameters.
Deduced.resize(TemplateParams->size());
SmallVector<QualType, 8> ParamTypesForArgChecking;
for (unsigned ParamIdx = 0, NumParamTypes = ParamTypes.size(), ArgIdx = 0;
     ParamIdx != NumParamTypes; ++ParamIdx) {
  QualType ParamType = ParamTypes[ParamIdx];

  const PackExpansionType *ParamExpansion =
      dyn_cast<PackExpansionType>(ParamType);
  if (!ParamExpansion) {
    // Simple case: matching a function parameter to a function argument.
    if (ArgIdx >= Args.size())
      break;

    ParamTypesForArgChecking.push_back(ParamType);
    if (auto Result = DeduceCallArgument(ParamType, ArgIdx++))
      return Result;

    continue;
  }

  QualType ParamPattern = ParamExpansion->getPattern();
  PackDeductionScope PackScope(*this, TemplateParams, Deduced, Info,
                               ParamPattern);

  // C++0x [temp.deduct.call]p1:
  //   For a function parameter pack that occurs at the end of the
  //   parameter-declaration-list, the type A of each remaining argument of
  //   the call is compared with the type P of the declarator-id of the
  //   function parameter pack. Each comparison deduces template arguments
  //   for subsequent positions in the template parameter packs expanded by
  //   the function parameter pack. When a function parameter pack appears
  //   in a non-deduced context [not at the end of the list], the type of
  //   that parameter pack is never deduced.
  //
  // FIXME: The above rule allows the size of the parameter pack to change
  // after we skip it (in the non-deduced case). That makes no sense, so
  // we instead notionally deduce the pack against N arguments, where N is
  // the length of the explicitly-specified pack if it's expanded by the
  // parameter pack and 0 otherwise, and we treat each deduction as a
  // non-deduced context.
  if (ParamIdx + 1 == NumParamTypes || PackScope.hasFixedArity()) {
    for (; ArgIdx < Args.size() && PackScope.hasNextElement();
         PackScope.nextPackElement(), ++ArgIdx) {
      ParamTypesForArgChecking.push_back(ParamPattern);
      if (auto Result = DeduceCallArgument(ParamPattern, ArgIdx))
        return Result;
    }
  } else {
    // If the parameter type contains an explicitly-specified pack that we
    // could not expand, skip the number of parameters notionally created
    // by the expansion.
    Optional<unsigned> NumExpansions = ParamExpansion->getNumExpansions();
    if (NumExpansions && !PackScope.isPartiallyExpanded()) {
      for (unsigned I = 0; I != *NumExpansions && ArgIdx < Args.size();
           ++I, ++ArgIdx) {
        ParamTypesForArgChecking.push_back(ParamPattern);
        // FIXME: Should we add OriginalCallArgs for these? What if the
        // corresponding argument is a list?
        PackScope.nextPackElement();
      }
    }
  }

  // Build argument packs for each of the parameter packs expanded by this
  // pack expansion.
  if (auto Result = PackScope.finish())
    return Result;
}

// Capture the context in which the function call is made. This is the context
// that is needed when the accessibility of template arguments is checked.
DeclContext *CallingCtx = CurContext;

return FinishTemplateArgumentDeduction(
    FunctionTemplate, Deduced, NumExplicitlySpecified, Specialization, Info,
    &OriginalCallArgs, PartialOverloading, [&, CallingCtx]() {
      ContextRAII SavedContext(*this, CallingCtx);
      return CheckNonDependent(ParamTypesForArgChecking);
    });
3960}

3962QualType Sema::adjustCCAndNoReturn(QualType ArgFunctionType,
                                 QualType FunctionType,
                                 bool AdjustExceptionSpec) {
if (ArgFunctionType.isNull())
  return ArgFunctionType;

const FunctionProtoType *FunctionTypeP =
    FunctionType->castAs<FunctionProtoType>();
const FunctionProtoType *ArgFunctionTypeP =
    ArgFunctionType->getAs<FunctionProtoType>();

FunctionProtoType::ExtProtoInfo EPI = ArgFunctionTypeP->getExtProtoInfo();
bool Rebuild = false;

CallingConv CC = FunctionTypeP->getCallConv();
if (EPI.ExtInfo.getCC() != CC) {
  EPI.ExtInfo = EPI.ExtInfo.withCallingConv(CC);
  Rebuild = true;
}

bool NoReturn = FunctionTypeP->getNoReturnAttr();
if (EPI.ExtInfo.getNoReturn() != NoReturn) {
  EPI.ExtInfo = EPI.ExtInfo.withNoReturn(NoReturn);
  Rebuild = true;
}

if (AdjustExceptionSpec && (FunctionTypeP->hasExceptionSpec() ||
                            ArgFunctionTypeP->hasExceptionSpec())) {
  EPI.ExceptionSpec = FunctionTypeP->getExtProtoInfo().ExceptionSpec;
  Rebuild = true;
}

if (!Rebuild)
  return ArgFunctionType;

return Context.getFunctionType(ArgFunctionTypeP->getReturnType(),
                               ArgFunctionTypeP->getParamTypes(), EPI);
3999}

4001/// Deduce template arguments when taking the address of a function
4002/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to
4003/// a template.
4004///
4005/// \param FunctionTemplate the function template for which we are performing
4006/// template argument deduction.
4007///
4008/// \param ExplicitTemplateArgs the explicitly-specified template
4009/// arguments.
4010///
4011/// \param ArgFunctionType the function type that will be used as the
4012/// "argument" type (A) when performing template argument deduction from the
4013/// function template's function type. This type may be NULL, if there is no
4014/// argument type to compare against, in C++0x [temp.arg.explicit]p3.
4015///
4016/// \param Specialization if template argument deduction was successful,
4017/// this will be set to the function template specialization produced by
4018/// template argument deduction.
4019///
4020/// \param Info the argument will be updated to provide additional information
4021/// about template argument deduction.
4022///
4023/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
4024/// the address of a function template per [temp.deduct.funcaddr] and
4025/// [over.over]. If \c false, we are looking up a function template
4026/// specialization based on its signature, per [temp.deduct.decl].
4027///
4028/// \returns the result of template argument deduction.
4029Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
  FunctionTemplateDecl *FunctionTemplate,
  TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType,
  FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
  bool IsAddressOfFunction) {
if (FunctionTemplate->isInvalidDecl())
  return TDK_Invalid;

FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
TemplateParameterList *TemplateParams
  = FunctionTemplate->getTemplateParameters();
QualType FunctionType = Function->getType();

// Substitute any explicit template arguments.
LocalInstantiationScope InstScope(*this);
SmallVector<DeducedTemplateArgument, 4> Deduced;
unsigned NumExplicitlySpecified = 0;
SmallVector<QualType, 4> ParamTypes;
if (ExplicitTemplateArgs) {
  if (TemplateDeductionResult Result
        = SubstituteExplicitTemplateArguments(FunctionTemplate,
                                              *ExplicitTemplateArgs,
                                              Deduced, ParamTypes,
                                              &FunctionType, Info))
    return Result;

  NumExplicitlySpecified = Deduced.size();
}

// When taking the address of a function, we require convertibility of
// the resulting function type. Otherwise, we allow arbitrary mismatches
// of calling convention and noreturn.
if (!IsAddressOfFunction)
  ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, FunctionType,
                                        /*AdjustExceptionSpec*/false);

// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);
SFINAETrap Trap(*this);

Deduced.resize(TemplateParams->size());

// If the function has a deduced return type, substitute it for a dependent
// type so that we treat it as a non-deduced context in what follows. If we
// are looking up by signature, the signature type should also have a deduced
// return type, which we instead expect to exactly match.
bool HasDeducedReturnType = false;
if (getLangOpts().CPlusPlus14 && IsAddressOfFunction &&
    Function->getReturnType()->getContainedAutoType()) {
  FunctionType = SubstAutoType(FunctionType, Context.DependentTy);
  HasDeducedReturnType = true;
}

if (!ArgFunctionType.isNull()) {
  unsigned TDF =
      TDF_TopLevelParameterTypeList | TDF_AllowCompatibleFunctionType;
  // Deduce template arguments from the function type.
  if (TemplateDeductionResult Result
        = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
                                             FunctionType, ArgFunctionType,
                                             Info, Deduced, TDF))
    return Result;
}

if (TemplateDeductionResult Result
      = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced,
                                        NumExplicitlySpecified,
                                        Specialization, Info))
  return Result;

// If the function has a deduced return type, deduce it now, so we can check
// that the deduced function type matches the requested type.
if (HasDeducedReturnType &&
    Specialization->getReturnType()->isUndeducedType() &&
    DeduceReturnType(Specialization, Info.getLocation(), false))
  return TDK_MiscellaneousDeductionFailure;

// If the function has a dependent exception specification, resolve it now,
// so we can check that the exception specification matches.
auto *SpecializationFPT =
    Specialization->getType()->castAs<FunctionProtoType>();
if (getLangOpts().CPlusPlus17 &&
    isUnresolvedExceptionSpec(SpecializationFPT->getExceptionSpecType()) &&
    !ResolveExceptionSpec(Info.getLocation(), SpecializationFPT))
  return TDK_MiscellaneousDeductionFailure;

// Adjust the exception specification of the argument to match the
// substituted and resolved type we just formed. (Calling convention and
// noreturn can't be dependent, so we don't actually need this for them
// right now.)
QualType SpecializationType = Specialization->getType();
if (!IsAddressOfFunction)
  ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, SpecializationType,
                                        /*AdjustExceptionSpec*/true);

// If the requested function type does not match the actual type of the
// specialization with respect to arguments of compatible pointer to function
// types, template argument deduction fails.
if (!ArgFunctionType.isNull()) {
  if (IsAddressOfFunction &&
      !isSameOrCompatibleFunctionType(
          Context.getCanonicalType(SpecializationType),
          Context.getCanonicalType(ArgFunctionType)))
    return TDK_MiscellaneousDeductionFailure;

  if (!IsAddressOfFunction &&
      !Context.hasSameType(SpecializationType, ArgFunctionType))
    return TDK_MiscellaneousDeductionFailure;
}

return TDK_Success;
4141}

4143/// Deduce template arguments for a templated conversion
4144/// function (C++ [temp.deduct.conv]) and, if successful, produce a
4145/// conversion function template specialization.
4146Sema::TemplateDeductionResult
4147Sema::DeduceTemplateArguments(FunctionTemplateDecl *ConversionTemplate,
                            QualType ToType,
                            CXXConversionDecl *&Specialization,
                            TemplateDeductionInfo &Info) {
if (ConversionTemplate->isInvalidDecl())
  return TDK_Invalid;

CXXConversionDecl *ConversionGeneric
  = cast<CXXConversionDecl>(ConversionTemplate->getTemplatedDecl());

QualType FromType = ConversionGeneric->getConversionType();

// Canonicalize the types for deduction.
QualType P = Context.getCanonicalType(FromType);
QualType A = Context.getCanonicalType(ToType);

// C++0x [temp.deduct.conv]p2:
//   If P is a reference type, the type referred to by P is used for
//   type deduction.
if (const ReferenceType *PRef = P->getAs<ReferenceType>())
  P = PRef->getPointeeType();

// C++0x [temp.deduct.conv]p4:
//   [...] If A is a reference type, the type referred to by A is used
//   for type deduction.
if (const ReferenceType *ARef = A->getAs<ReferenceType>()) {
  A = ARef->getPointeeType();
  // We work around a defect in the standard here: cv-qualifiers are also
  // removed from P and A in this case, unless P was a reference type. This
  // seems to mostly match what other compilers are doing.
  if (!FromType->getAs<ReferenceType>()) {
    A = A.getUnqualifiedType();
    P = P.getUnqualifiedType();
  }

// C++ [temp.deduct.conv]p3:
//
//   If A is not a reference type:
} else {
  assert(!A->isReferenceType() && "Reference types were handled above")((!A->isReferenceType() && "Reference types were handled above"
) ? static_cast<void> (0) : __assert_fail ("!A->isReferenceType() && \"Reference types were handled above\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4186, __PRETTY_FUNCTION__));

  //   - If P is an array type, the pointer type produced by the
  //     array-to-pointer standard conversion (4.2) is used in place
  //     of P for type deduction; otherwise,
  if (P->isArrayType())
    P = Context.getArrayDecayedType(P);
  //   - If P is a function type, the pointer type produced by the
  //     function-to-pointer standard conversion (4.3) is used in
  //     place of P for type deduction; otherwise,
  else if (P->isFunctionType())
    P = Context.getPointerType(P);
  //   - If P is a cv-qualified type, the top level cv-qualifiers of
  //     P's type are ignored for type deduction.
  else
    P = P.getUnqualifiedType();

  // C++0x [temp.deduct.conv]p4:
  //   If A is a cv-qualified type, the top level cv-qualifiers of A's
  //   type are ignored for type deduction. If A is a reference type, the type
  //   referred to by A is used for type deduction.
  A = A.getUnqualifiedType();
}

// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(
    *this, Sema::ExpressionEvaluationContext::Unevaluated);
SFINAETrap Trap(*this);

// C++ [temp.deduct.conv]p1:
//   Template argument deduction is done by comparing the return
//   type of the template conversion function (call it P) with the
//   type that is required as the result of the conversion (call it
//   A) as described in 14.8.2.4.
TemplateParameterList *TemplateParams
  = ConversionTemplate->getTemplateParameters();
SmallVector<DeducedTemplateArgument, 4> Deduced;
Deduced.resize(TemplateParams->size());

// C++0x [temp.deduct.conv]p4:
//   In general, the deduction process attempts to find template
//   argument values that will make the deduced A identical to
//   A. However, there are two cases that allow a difference:
unsigned TDF = 0;
//     - If the original A is a reference type, A can be more
//       cv-qualified than the deduced A (i.e., the type referred to
//       by the reference)
if (ToType->isReferenceType())
  TDF |= TDF_ArgWithReferenceType;
//     - The deduced A can be another pointer or pointer to member
//       type that can be converted to A via a qualification
//       conversion.
//
// (C++0x [temp.deduct.conv]p6 clarifies that this only happens when
// both P and A are pointers or member pointers. In this case, we
// just ignore cv-qualifiers completely).
if ((P->isPointerType() && A->isPointerType()) ||
    (P->isMemberPointerType() && A->isMemberPointerType()))
  TDF |= TDF_IgnoreQualifiers;
if (TemplateDeductionResult Result
      = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
                                           P, A, Info, Deduced, TDF))
  return Result;

// Create an Instantiation Scope for finalizing the operator.
LocalInstantiationScope InstScope(*this);
// Finish template argument deduction.
FunctionDecl *ConversionSpecialized = nullptr;
TemplateDeductionResult Result
    = FinishTemplateArgumentDeduction(ConversionTemplate, Deduced, 0,
                                      ConversionSpecialized, Info);
Specialization = cast_or_null<CXXConversionDecl>(ConversionSpecialized);
return Result;
4259}

4261/// Deduce template arguments for a function template when there is
4262/// nothing to deduce against (C++0x [temp.arg.explicit]p3).
4263///
4264/// \param FunctionTemplate the function template for which we are performing
4265/// template argument deduction.
4266///
4267/// \param ExplicitTemplateArgs the explicitly-specified template
4268/// arguments.
4269///
4270/// \param Specialization if template argument deduction was successful,
4271/// this will be set to the function template specialization produced by
4272/// template argument deduction.
4273///
4274/// \param Info the argument will be updated to provide additional information
4275/// about template argument deduction.
4276///
4277/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
4278/// the address of a function template in a context where we do not have a
4279/// target type, per [over.over]. If \c false, we are looking up a function
4280/// template specialization based on its signature, which only happens when
4281/// deducing a function parameter type from an argument that is a template-id
4282/// naming a function template specialization.
4283///
4284/// \returns the result of template argument deduction.
4285Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
  FunctionTemplateDecl *FunctionTemplate,
  TemplateArgumentListInfo *ExplicitTemplateArgs,
  FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
  bool IsAddressOfFunction) {
return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs,
                               QualType(), Specialization, Info,
                               IsAddressOfFunction);
4293}

4295namespace {
struct DependentAuto { bool IsPack; };

/// Substitute the 'auto' specifier or deduced template specialization type
/// specifier within a type for a given replacement type.
class SubstituteDeducedTypeTransform :
    public TreeTransform<SubstituteDeducedTypeTransform> {
  QualType Replacement;
  bool ReplacementIsPack;
  bool UseTypeSugar;

public:
  SubstituteDeducedTypeTransform(Sema &SemaRef, DependentAuto DA)
      : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef), Replacement(),
        ReplacementIsPack(DA.IsPack), UseTypeSugar(true) {}

  SubstituteDeducedTypeTransform(Sema &SemaRef, QualType Replacement,
                                 bool UseTypeSugar = true)
      : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef),
        Replacement(Replacement), ReplacementIsPack(false),
        UseTypeSugar(UseTypeSugar) {}

  QualType TransformDesugared(TypeLocBuilder &TLB, DeducedTypeLoc TL) {
    assert(isa<TemplateTypeParmType>(Replacement) &&((isa<TemplateTypeParmType>(Replacement) && "unexpected unsugared replacement kind"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateTypeParmType>(Replacement) && \"unexpected unsugared replacement kind\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4319, __PRETTY_FUNCTION__))
           "unexpected unsugared replacement kind")((isa<TemplateTypeParmType>(Replacement) && "unexpected unsugared replacement kind"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateTypeParmType>(Replacement) && \"unexpected unsugared replacement kind\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4319, __PRETTY_FUNCTION__));
    QualType Result = Replacement;
    TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
    NewTL.setNameLoc(TL.getNameLoc());
    return Result;
  }

  QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) {
    // If we're building the type pattern to deduce against, don't wrap the
    // substituted type in an AutoType. Certain template deduction rules
    // apply only when a template type parameter appears directly (and not if
    // the parameter is found through desugaring). For instance:
    //   auto &&lref = lvalue;
    // must transform into "rvalue reference to T" not "rvalue reference to
    // auto type deduced as T" in order for [temp.deduct.call]p3 to apply.
    //
    // FIXME: Is this still necessary?
    if (!UseTypeSugar)
      return TransformDesugared(TLB, TL);

    QualType Result = SemaRef.Context.getAutoType(
        Replacement, TL.getTypePtr()->getKeyword(), Replacement.isNull(),
        ReplacementIsPack);
    auto NewTL = TLB.push<AutoTypeLoc>(Result);
    NewTL.setNameLoc(TL.getNameLoc());
    return Result;
  }

  QualType TransformDeducedTemplateSpecializationType(
      TypeLocBuilder &TLB, DeducedTemplateSpecializationTypeLoc TL) {
    if (!UseTypeSugar)
      return TransformDesugared(TLB, TL);

    QualType Result = SemaRef.Context.getDeducedTemplateSpecializationType(
        TL.getTypePtr()->getTemplateName(),
        Replacement, Replacement.isNull());
    auto NewTL = TLB.push<DeducedTemplateSpecializationTypeLoc>(Result);
    NewTL.setNameLoc(TL.getNameLoc());
    return Result;
  }

  ExprResult TransformLambdaExpr(LambdaExpr *E) {
    // Lambdas never need to be transformed.
    return E;
  }

  QualType Apply(TypeLoc TL) {
    // Create some scratch storage for the transformed type locations.
    // FIXME: We're just going to throw this information away. Don't build it.
    TypeLocBuilder TLB;
    TLB.reserve(TL.getFullDataSize());
    return TransformType(TLB, TL);
  }
};

4374} // namespace

4376Sema::DeduceAutoResult
4377Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, QualType &Result,
                   Optional<unsigned> DependentDeductionDepth) {
return DeduceAutoType(Type->getTypeLoc(), Init, Result,
                      DependentDeductionDepth);
4381}

4383/// Attempt to produce an informative diagostic explaining why auto deduction
4384/// failed.
4385/// \return \c true if diagnosed, \c false if not.
4386static bool diagnoseAutoDeductionFailure(Sema &S,
                                       Sema::TemplateDeductionResult TDK,
                                       TemplateDeductionInfo &Info,
                                       ArrayRef<SourceRange> Ranges) {
switch (TDK) {
case Sema::TDK_Inconsistent: {
  // Inconsistent deduction means we were deducing from an initializer list.
  auto D = S.Diag(Info.getLocation(), diag::err_auto_inconsistent_deduction);
  D << Info.FirstArg << Info.SecondArg;
  for (auto R : Ranges)
    D << R;
  return true;
}

// FIXME: Are there other cases for which a custom diagnostic is more useful
// than the basic "types don't match" diagnostic?

default:
  return false;
}
4406}

4408/// Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6)
4409///
4410/// Note that this is done even if the initializer is dependent. (This is
4411/// necessary to support partial ordering of templates using 'auto'.)
4412/// A dependent type will be produced when deducing from a dependent type.
4413///
4414/// \param Type the type pattern using the auto type-specifier.
4415/// \param Init the initializer for the variable whose type is to be deduced.
4416/// \param Result if type deduction was successful, this will be set to the
4417///        deduced type.
4418/// \param DependentDeductionDepth Set if we should permit deduction in
4419///        dependent cases. This is necessary for template partial ordering with
4420///        'auto' template parameters. The value specified is the template
4421///        parameter depth at which we should perform 'auto' deduction.
4422Sema::DeduceAutoResult
4423Sema::DeduceAutoType(TypeLoc Type, Expr *&Init, QualType &Result,
                   Optional<unsigned> DependentDeductionDepth) {
if (Init->getType()->isNonOverloadPlaceholderType()) {
  ExprResult NonPlaceholder = CheckPlaceholderExpr(Init);
  if (NonPlaceholder.isInvalid())
    return DAR_FailedAlreadyDiagnosed;
  Init = NonPlaceholder.get();
}

DependentAuto DependentResult = {
    /*.IsPack = */ (bool)Type.getAs<PackExpansionTypeLoc>()};

if (!DependentDeductionDepth &&
    (Type.getType()->isDependentType() || Init->isTypeDependent())) {
  Result = SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type);
  assert(!Result.isNull() && "substituting DependentTy can't fail")((!Result.isNull() && "substituting DependentTy can't fail"
) ? static_cast<void> (0) : __assert_fail ("!Result.isNull() && \"substituting DependentTy can't fail\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4438, __PRETTY_FUNCTION__));
  return DAR_Succeeded;
}

// Find the depth of template parameter to synthesize.
unsigned Depth = DependentDeductionDepth.getValueOr(0);

// If this is a 'decltype(auto)' specifier, do the decltype dance.
// Since 'decltype(auto)' can only occur at the top of the type, we
// don't need to go digging for it.
if (const AutoType *AT = Type.getType()->getAs<AutoType>()) {
  if (AT->isDecltypeAuto()) {
    if (isa<InitListExpr>(Init)) {
      Diag(Init->getBeginLoc(), diag::err_decltype_auto_initializer_list);
      return DAR_FailedAlreadyDiagnosed;
    }

    ExprResult ER = CheckPlaceholderExpr(Init);
    if (ER.isInvalid())
      return DAR_FailedAlreadyDiagnosed;
    Init = ER.get();
    QualType Deduced = BuildDecltypeType(Init, Init->getBeginLoc(), false);
    if (Deduced.isNull())
      return DAR_FailedAlreadyDiagnosed;
    // FIXME: Support a non-canonical deduced type for 'auto'.
    Deduced = Context.getCanonicalType(Deduced);
    Result = SubstituteDeducedTypeTransform(*this, Deduced).Apply(Type);
    if (Result.isNull())
      return DAR_FailedAlreadyDiagnosed;
    return DAR_Succeeded;
  } else if (!getLangOpts().CPlusPlus) {
    if (isa<InitListExpr>(Init)) {
      Diag(Init->getBeginLoc(), diag::err_auto_init_list_from_c);
      return DAR_FailedAlreadyDiagnosed;
    }
  }
}

SourceLocation Loc = Init->getExprLoc();

LocalInstantiationScope InstScope(*this);

// Build template<class TemplParam> void Func(FuncParam);
TemplateTypeParmDecl *TemplParam = TemplateTypeParmDecl::Create(
    Context, nullptr, SourceLocation(), Loc, Depth, 0, nullptr, false, false);
QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0);
NamedDecl *TemplParamPtr = TemplParam;
FixedSizeTemplateParameterListStorage<1, false> TemplateParamsSt(
    Loc, Loc, TemplParamPtr, Loc, nullptr);

QualType FuncParam =
    SubstituteDeducedTypeTransform(*this, TemplArg, /*UseTypeSugar*/false)
        .Apply(Type);
assert(!FuncParam.isNull() &&((!FuncParam.isNull() && "substituting template parameter for 'auto' failed"
) ? static_cast<void> (0) : __assert_fail ("!FuncParam.isNull() && \"substituting template parameter for 'auto' failed\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4492, __PRETTY_FUNCTION__))
       "substituting template parameter for 'auto' failed")((!FuncParam.isNull() && "substituting template parameter for 'auto' failed"
) ? static_cast<void> (0) : __assert_fail ("!FuncParam.isNull() && \"substituting template parameter for 'auto' failed\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4492, __PRETTY_FUNCTION__));

// Deduce type of TemplParam in Func(Init)
SmallVector<DeducedTemplateArgument, 1> Deduced;
Deduced.resize(1);

TemplateDeductionInfo Info(Loc, Depth);

// If deduction failed, don't diagnose if the initializer is dependent; it
// might acquire a matching type in the instantiation.
auto DeductionFailed = [&](TemplateDeductionResult TDK,
                           ArrayRef<SourceRange> Ranges) -> DeduceAutoResult {
  if (Init->isTypeDependent()) {
    Result =
        SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type);
    assert(!Result.isNull() && "substituting DependentTy can't fail")((!Result.isNull() && "substituting DependentTy can't fail"
) ? static_cast<void> (0) : __assert_fail ("!Result.isNull() && \"substituting DependentTy can't fail\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4507, __PRETTY_FUNCTION__));
    return DAR_Succeeded;
  }
  if (diagnoseAutoDeductionFailure(*this, TDK, Info, Ranges))
    return DAR_FailedAlreadyDiagnosed;
  return DAR_Failed;
};

SmallVector<OriginalCallArg, 4> OriginalCallArgs;

InitListExpr *InitList = dyn_cast<InitListExpr>(Init);
if (InitList) {
  // Notionally, we substitute std::initializer_list<T> for 'auto' and deduce
  // against that. Such deduction only succeeds if removing cv-qualifiers and
  // references results in std::initializer_list<T>.
  if (!Type.getType().getNonReferenceType()->getAs<AutoType>())
    return DAR_Failed;

  // Resolving a core issue: a braced-init-list containing any designators is
  // a non-deduced context.
  for (Expr *E : InitList->inits())
    if (isa<DesignatedInitExpr>(E))
      return DAR_Failed;

  SourceRange DeducedFromInitRange;
  for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) {
    Expr *Init = InitList->getInit(i);

    if (auto TDK = DeduceTemplateArgumentsFromCallArgument(
            *this, TemplateParamsSt.get(), 0, TemplArg, Init,
            Info, Deduced, OriginalCallArgs, /*Decomposed*/ true,
            /*ArgIdx*/ 0, /*TDF*/ 0))
      return DeductionFailed(TDK, {DeducedFromInitRange,
                                   Init->getSourceRange()});

    if (DeducedFromInitRange.isInvalid() &&
        Deduced[0].getKind() != TemplateArgument::Null)
      DeducedFromInitRange = Init->getSourceRange();
  }
} else {
  if (!getLangOpts().CPlusPlus && Init->refersToBitField()) {
    Diag(Loc, diag::err_auto_bitfield);
    return DAR_FailedAlreadyDiagnosed;
  }

  if (auto TDK = DeduceTemplateArgumentsFromCallArgument(
          *this, TemplateParamsSt.get(), 0, FuncParam, Init, Info, Deduced,
          OriginalCallArgs, /*Decomposed*/ false, /*ArgIdx*/ 0, /*TDF*/ 0))
    return DeductionFailed(TDK, {});
}

// Could be null if somehow 'auto' appears in a non-deduced context.
if (Deduced[0].getKind() != TemplateArgument::Type)
  return DeductionFailed(TDK_Incomplete, {});

QualType DeducedType = Deduced[0].getAsType();

if (InitList) {
  DeducedType = BuildStdInitializerList(DeducedType, Loc);
  if (DeducedType.isNull())
    return DAR_FailedAlreadyDiagnosed;
}

Result = SubstituteDeducedTypeTransform(*this, DeducedType).Apply(Type);
if (Result.isNull())
  return DAR_FailedAlreadyDiagnosed;

// Check that the deduced argument type is compatible with the original
// argument type per C++ [temp.deduct.call]p4.
QualType DeducedA = InitList ? Deduced[0].getAsType() : Result;
for (const OriginalCallArg &OriginalArg : OriginalCallArgs) {
  assert((bool)InitList == OriginalArg.DecomposedParam &&(((bool)InitList == OriginalArg.DecomposedParam && "decomposed non-init-list in auto deduction?"
) ? static_cast<void> (0) : __assert_fail ("(bool)InitList == OriginalArg.DecomposedParam && \"decomposed non-init-list in auto deduction?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4579, __PRETTY_FUNCTION__))
         "decomposed non-init-list in auto deduction?")(((bool)InitList == OriginalArg.DecomposedParam && "decomposed non-init-list in auto deduction?"
) ? static_cast<void> (0) : __assert_fail ("(bool)InitList == OriginalArg.DecomposedParam && \"decomposed non-init-list in auto deduction?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4579, __PRETTY_FUNCTION__));
  if (auto TDK =
          CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA)) {
    Result = QualType();
    return DeductionFailed(TDK, {});
  }
}

return DAR_Succeeded;
4588}

4590QualType Sema::SubstAutoType(QualType TypeWithAuto,
                           QualType TypeToReplaceAuto) {
if (TypeToReplaceAuto->isDependentType())
  return SubstituteDeducedTypeTransform(
             *this, DependentAuto{
                        TypeToReplaceAuto->containsUnexpandedParameterPack()})
      .TransformType(TypeWithAuto);
return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto)
    .TransformType(TypeWithAuto);
4599}

4601TypeSourceInfo *Sema::SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
                                            QualType TypeToReplaceAuto) {
if (TypeToReplaceAuto->isDependentType())
  return SubstituteDeducedTypeTransform(
             *this,
             DependentAuto{
                 TypeToReplaceAuto->containsUnexpandedParameterPack()})
      .TransformType(TypeWithAuto);
return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto)
    .TransformType(TypeWithAuto);
4611}

4613QualType Sema::ReplaceAutoType(QualType TypeWithAuto,
                             QualType TypeToReplaceAuto) {
return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto,
                                      /*UseTypeSugar*/ false)
    .TransformType(TypeWithAuto);
4618}

4620void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) {
if (isa<InitListExpr>(Init))
  Diag(VDecl->getLocation(),
       VDecl->isInitCapture()
           ? diag::err_init_capture_deduction_failure_from_init_list
           : diag::err_auto_var_deduction_failure_from_init_list)
    << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange();
else
  Diag(VDecl->getLocation(),
       VDecl->isInitCapture() ? diag::err_init_capture_deduction_failure
                              : diag::err_auto_var_deduction_failure)
    << VDecl->getDeclName() << VDecl->getType() << Init->getType()
    << Init->getSourceRange();
4633}

4635bool Sema::DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
                          bool Diagnose) {
assert(FD->getReturnType()->isUndeducedType())((FD->getReturnType()->isUndeducedType()) ? static_cast
<void> (0) : __assert_fail ("FD->getReturnType()->isUndeducedType()"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4637, __PRETTY_FUNCTION__));

// For a lambda's conversion operator, deduce any 'auto' or 'decltype(auto)'
// within the return type from the call operator's type.
if (isLambdaConversionOperator(FD)) {
  CXXRecordDecl *Lambda = cast<CXXMethodDecl>(FD)->getParent();
  FunctionDecl *CallOp = Lambda->getLambdaCallOperator();

  // For a generic lambda, instantiate the call operator if needed.
  if (auto *Args = FD->getTemplateSpecializationArgs()) {
    CallOp = InstantiateFunctionDeclaration(
        CallOp->getDescribedFunctionTemplate(), Args, Loc);
    if (!CallOp || CallOp->isInvalidDecl())
      return true;

    // We might need to deduce the return type by instantiating the definition
    // of the operator() function.
    if (CallOp->getReturnType()->isUndeducedType()) {
      runWithSufficientStackSpace(Loc, [&] {
        InstantiateFunctionDefinition(Loc, CallOp);
      });
    }
  }

  if (CallOp->isInvalidDecl())
    return true;
  assert(!CallOp->getReturnType()->isUndeducedType() &&((!CallOp->getReturnType()->isUndeducedType() &&
 "failed to deduce lambda return type") ? static_cast<void
> (0) : __assert_fail ("!CallOp->getReturnType()->isUndeducedType() && \"failed to deduce lambda return type\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4664, __PRETTY_FUNCTION__))
         "failed to deduce lambda return type")((!CallOp->getReturnType()->isUndeducedType() &&
 "failed to deduce lambda return type") ? static_cast<void
> (0) : __assert_fail ("!CallOp->getReturnType()->isUndeducedType() && \"failed to deduce lambda return type\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4664, __PRETTY_FUNCTION__));

  // Build the new return type from scratch.
  QualType RetType = getLambdaConversionFunctionResultType(
      CallOp->getType()->castAs<FunctionProtoType>());
  if (FD->getReturnType()->getAs<PointerType>())
    RetType = Context.getPointerType(RetType);
  else {
    assert(FD->getReturnType()->getAs<BlockPointerType>())((FD->getReturnType()->getAs<BlockPointerType>())
 ? static_cast<void> (0) : __assert_fail ("FD->getReturnType()->getAs<BlockPointerType>()"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4672, __PRETTY_FUNCTION__));
    RetType = Context.getBlockPointerType(RetType);
  }
  Context.adjustDeducedFunctionResultType(FD, RetType);
  return false;
}

if (FD->getTemplateInstantiationPattern()) {
  runWithSufficientStackSpace(Loc, [&] {
    InstantiateFunctionDefinition(Loc, FD);
  });
}

bool StillUndeduced = FD->getReturnType()->isUndeducedType();
if (StillUndeduced && Diagnose && !FD->isInvalidDecl()) {
  Diag(Loc, diag::err_auto_fn_used_before_defined) << FD;
  Diag(FD->getLocation(), diag::note_callee_decl) << FD;
}

return StillUndeduced;
4692}

4694/// If this is a non-static member function,
4695static void
4696AddImplicitObjectParameterType(ASTContext &Context,
                             CXXMethodDecl *Method,
                             SmallVectorImpl<QualType> &ArgTypes) {
// C++11 [temp.func.order]p3:
//   [...] The new parameter is of type "reference to cv A," where cv are
//   the cv-qualifiers of the function template (if any) and A is
//   the class of which the function template is a member.
//
// The standard doesn't say explicitly, but we pick the appropriate kind of
// reference type based on [over.match.funcs]p4.
QualType ArgTy = Context.getTypeDeclType(Method->getParent());
ArgTy = Context.getQualifiedType(ArgTy, Method->getMethodQualifiers());
if (Method->getRefQualifier() == RQ_RValue)
  ArgTy = Context.getRValueReferenceType(ArgTy);
else
  ArgTy = Context.getLValueReferenceType(ArgTy);
ArgTypes.push_back(ArgTy);
4713}

4715/// Determine whether the function template \p FT1 is at least as
4716/// specialized as \p FT2.
4717static bool isAtLeastAsSpecializedAs(Sema &S,
                                   SourceLocation Loc,
                                   FunctionTemplateDecl *FT1,
                                   FunctionTemplateDecl *FT2,
                                   TemplatePartialOrderingContext TPOC,
                                   unsigned NumCallArguments1) {
FunctionDecl *FD1 = FT1->getTemplatedDecl();
FunctionDecl *FD2 = FT2->getTemplatedDecl();
const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>();
const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>();

assert(Proto1 && Proto2 && "Function templates must have prototypes")((Proto1 && Proto2 && "Function templates must have prototypes"
) ? static_cast<void> (0) : __assert_fail ("Proto1 && Proto2 && \"Function templates must have prototypes\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4728, __PRETTY_FUNCTION__));
TemplateParameterList *TemplateParams = FT2->getTemplateParameters();
SmallVector<DeducedTemplateArgument, 4> Deduced;
Deduced.resize(TemplateParams->size());

// C++0x [temp.deduct.partial]p3:
//   The types used to determine the ordering depend on the context in which
//   the partial ordering is done:
TemplateDeductionInfo Info(Loc);
SmallVector<QualType, 4> Args2;
switch (TPOC) {
case TPOC_Call: {
  //   - In the context of a function call, the function parameter types are
  //     used.
  CXXMethodDecl *Method1 = dyn_cast<CXXMethodDecl>(FD1);
  CXXMethodDecl *Method2 = dyn_cast<CXXMethodDecl>(FD2);

  // C++11 [temp.func.order]p3:
  //   [...] If only one of the function templates is a non-static
  //   member, that function template is considered to have a new
  //   first parameter inserted in its function parameter list. The
  //   new parameter is of type "reference to cv A," where cv are
  //   the cv-qualifiers of the function template (if any) and A is
  //   the class of which the function template is a member.
  //
  // Note that we interpret this to mean "if one of the function
  // templates is a non-static member and the other is a non-member";
  // otherwise, the ordering rules for static functions against non-static
  // functions don't make any sense.
  //
  // C++98/03 doesn't have this provision but we've extended DR532 to cover
  // it as wording was broken prior to it.
  SmallVector<QualType, 4> Args1;

  unsigned NumComparedArguments = NumCallArguments1;

  if (!Method2 && Method1 && !Method1->isStatic()) {
    // Compare 'this' from Method1 against first parameter from Method2.
    AddImplicitObjectParameterType(S.Context, Method1, Args1);
    ++NumComparedArguments;
  } else if (!Method1 && Method2 && !Method2->isStatic()) {
    // Compare 'this' from Method2 against first parameter from Method1.
    AddImplicitObjectParameterType(S.Context, Method2, Args2);
  }

  Args1.insert(Args1.end(), Proto1->param_type_begin(),
               Proto1->param_type_end());
  Args2.insert(Args2.end(), Proto2->param_type_begin(),
               Proto2->param_type_end());

  // C++ [temp.func.order]p5:
  //   The presence of unused ellipsis and default arguments has no effect on
  //   the partial ordering of function templates.
  if (Args1.size() > NumComparedArguments)
    Args1.resize(NumComparedArguments);
  if (Args2.size() > NumComparedArguments)
    Args2.resize(NumComparedArguments);
  if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(),
                              Args1.data(), Args1.size(), Info, Deduced,
                              TDF_None, /*PartialOrdering=*/true))
    return false;

  break;
}

case TPOC_Conversion:
  //   - In the context of a call to a conversion operator, the return types
  //     of the conversion function templates are used.
  if (DeduceTemplateArgumentsByTypeMatch(
          S, TemplateParams, Proto2->getReturnType(), Proto1->getReturnType(),
          Info, Deduced, TDF_None,
          /*PartialOrdering=*/true))
    return false;
  break;

case TPOC_Other:
  //   - In other contexts (14.6.6.2) the function template's function type
  //     is used.
  if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                         FD2->getType(), FD1->getType(),
                                         Info, Deduced, TDF_None,
                                         /*PartialOrdering=*/true))
    return false;
  break;
}

// C++0x [temp.deduct.partial]p11:
//   In most cases, all template parameters must have values in order for
//   deduction to succeed, but for partial ordering purposes a template
//   parameter may remain without a value provided it is not used in the
//   types being used for partial ordering. [ Note: a template parameter used
//   in a non-deduced context is considered used. -end note]
unsigned ArgIdx = 0, NumArgs = Deduced.size();
for (; ArgIdx != NumArgs; ++ArgIdx)
  if (Deduced[ArgIdx].isNull())
    break;

// FIXME: We fail to implement [temp.deduct.type]p1 along this path. We need
// to substitute the deduced arguments back into the template and check that
// we get the right type.

if (ArgIdx == NumArgs) {
  // All template arguments were deduced. FT1 is at least as specialized
  // as FT2.
  return true;
}

// Figure out which template parameters were used.
llvm::SmallBitVector UsedParameters(TemplateParams->size());
switch (TPOC) {
case TPOC_Call:
  for (unsigned I = 0, N = Args2.size(); I != N; ++I)
    ::MarkUsedTemplateParameters(S.Context, Args2[I], false,
                                 TemplateParams->getDepth(),
                                 UsedParameters);
  break;

case TPOC_Conversion:
  ::MarkUsedTemplateParameters(S.Context, Proto2->getReturnType(), false,
                               TemplateParams->getDepth(), UsedParameters);
  break;

case TPOC_Other:
  ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false,
                               TemplateParams->getDepth(),
                               UsedParameters);
  break;
}

for (; ArgIdx != NumArgs; ++ArgIdx)
  // If this argument had no value deduced but was used in one of the types
  // used for partial ordering, then deduction fails.
  if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx])
    return false;

return true;
4864}

4866/// Determine whether this a function template whose parameter-type-list
4867/// ends with a function parameter pack.
4868static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) {
FunctionDecl *Function = FunTmpl->getTemplatedDecl();
unsigned NumParams = Function->getNumParams();
if (NumParams == 0)
  return false;

ParmVarDecl *Last = Function->getParamDecl(NumParams - 1);
if (!Last->isParameterPack())
  return false;

// Make sure that no previous parameter is a parameter pack.
while (--NumParams > 0) {
  if (Function->getParamDecl(NumParams - 1)->isParameterPack())
    return false;
}

return true;
4885}

4887/// Returns the more specialized function template according
4888/// to the rules of function template partial ordering (C++ [temp.func.order]).
4889///
4890/// \param FT1 the first function template
4891///
4892/// \param FT2 the second function template
4893///
4894/// \param TPOC the context in which we are performing partial ordering of
4895/// function templates.
4896///
4897/// \param NumCallArguments1 The number of arguments in the call to FT1, used
4898/// only when \c TPOC is \c TPOC_Call.
4899///
4900/// \param NumCallArguments2 The number of arguments in the call to FT2, used
4901/// only when \c TPOC is \c TPOC_Call.
4902///
4903/// \returns the more specialized function template. If neither
4904/// template is more specialized, returns NULL.
4905FunctionTemplateDecl *
4906Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1,
                               FunctionTemplateDecl *FT2,
                               SourceLocation Loc,
                               TemplatePartialOrderingContext TPOC,
                               unsigned NumCallArguments1,
                               unsigned NumCallArguments2) {
bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC,
                                        NumCallArguments1);
bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC,
                                        NumCallArguments2);

if (Better1 != Better2) // We have a clear winner
  return Better1 ? FT1 : FT2;

if (!Better1 && !Better2) // Neither is better than the other
  return nullptr;

// FIXME: This mimics what GCC implements, but doesn't match up with the
// proposed resolution for core issue 692. This area needs to be sorted out,
// but for now we attempt to maintain compatibility.
bool Variadic1 = isVariadicFunctionTemplate(FT1);
bool Variadic2 = isVariadicFunctionTemplate(FT2);
if (Variadic1 != Variadic2)
  return Variadic1? FT2 : FT1;

return nullptr;
4932}

4934/// Determine if the two templates are equivalent.
4935static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) {
if (T1 == T2)
  return true;

if (!T1 || !T2)
  return false;

return T1->getCanonicalDecl() == T2->getCanonicalDecl();
4943}

4945/// Retrieve the most specialized of the given function template
4946/// specializations.
4947///
4948/// \param SpecBegin the start iterator of the function template
4949/// specializations that we will be comparing.
4950///
4951/// \param SpecEnd the end iterator of the function template
4952/// specializations, paired with \p SpecBegin.
4953///
4954/// \param Loc the location where the ambiguity or no-specializations
4955/// diagnostic should occur.
4956///
4957/// \param NoneDiag partial diagnostic used to diagnose cases where there are
4958/// no matching candidates.
4959///
4960/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one
4961/// occurs.
4962///
4963/// \param CandidateDiag partial diagnostic used for each function template
4964/// specialization that is a candidate in the ambiguous ordering. One parameter
4965/// in this diagnostic should be unbound, which will correspond to the string
4966/// describing the template arguments for the function template specialization.
4967///
4968/// \returns the most specialized function template specialization, if
4969/// found. Otherwise, returns SpecEnd.
4970UnresolvedSetIterator Sema::getMostSpecialized(
  UnresolvedSetIterator SpecBegin, UnresolvedSetIterator SpecEnd,
  TemplateSpecCandidateSet &FailedCandidates,
  SourceLocation Loc, const PartialDiagnostic &NoneDiag,
  const PartialDiagnostic &AmbigDiag, const PartialDiagnostic &CandidateDiag,
  bool Complain, QualType TargetType) {
if (SpecBegin == SpecEnd) {
  if (Complain) {
    Diag(Loc, NoneDiag);
    FailedCandidates.NoteCandidates(*this, Loc);
  }
  return SpecEnd;
}

if (SpecBegin + 1 == SpecEnd)
  return SpecBegin;

// Find the function template that is better than all of the templates it
// has been compared to.
UnresolvedSetIterator Best = SpecBegin;
FunctionTemplateDecl *BestTemplate
  = cast<FunctionDecl>(*Best)->getPrimaryTemplate();
assert(BestTemplate && "Not a function template specialization?")((BestTemplate && "Not a function template specialization?"
) ? static_cast<void> (0) : __assert_fail ("BestTemplate && \"Not a function template specialization?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4992, __PRETTY_FUNCTION__));
for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) {
  FunctionTemplateDecl *Challenger
    = cast<FunctionDecl>(*I)->getPrimaryTemplate();
  assert(Challenger && "Not a function template specialization?")((Challenger && "Not a function template specialization?"
) ? static_cast<void> (0) : __assert_fail ("Challenger && \"Not a function template specialization?\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4996, __PRETTY_FUNCTION__));
  if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
                                                Loc, TPOC_Other, 0, 0),
                     Challenger)) {
    Best = I;
    BestTemplate = Challenger;
  }
}

// Make sure that the "best" function template is more specialized than all
// of the others.
bool Ambiguous = false;
for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
  FunctionTemplateDecl *Challenger
    = cast<FunctionDecl>(*I)->getPrimaryTemplate();
  if (I != Best &&
      !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
                                                 Loc, TPOC_Other, 0, 0),
                      BestTemplate)) {
    Ambiguous = true;
    break;
  }
}

if (!Ambiguous) {
  // We found an answer. Return it.
  return Best;
}

// Diagnose the ambiguity.
if (Complain) {
  Diag(Loc, AmbigDiag);

  // FIXME: Can we order the candidates in some sane way?
  for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
    PartialDiagnostic PD = CandidateDiag;
    const auto *FD = cast<FunctionDecl>(*I);
    PD << FD << getTemplateArgumentBindingsText(
                    FD->getPrimaryTemplate()->getTemplateParameters(),
                    *FD->getTemplateSpecializationArgs());
    if (!TargetType.isNull())
      HandleFunctionTypeMismatch(PD, FD->getType(), TargetType);
    Diag((*I)->getLocation(), PD);
  }
}

return SpecEnd;
5043}

5045/// Determine whether one partial specialization, P1, is at least as
5046/// specialized than another, P2.
5047///
5048/// \tparam TemplateLikeDecl The kind of P2, which must be a
5049/// TemplateDecl or {Class,Var}TemplatePartialSpecializationDecl.
5050/// \param T1 The injected-class-name of P1 (faked for a variable template).
5051/// \param T2 The injected-class-name of P2 (faked for a variable template).
5052template<typename TemplateLikeDecl>
5053static bool isAtLeastAsSpecializedAs(Sema &S, QualType T1, QualType T2,
                                   TemplateLikeDecl *P2,
                                   TemplateDeductionInfo &Info) {
// C++ [temp.class.order]p1:
//   For two class template partial specializations, the first is at least as
//   specialized as the second if, given the following rewrite to two
//   function templates, the first function template is at least as
//   specialized as the second according to the ordering rules for function
//   templates (14.6.6.2):
//     - the first function template has the same template parameters as the
//       first partial specialization and has a single function parameter
//       whose type is a class template specialization with the template
//       arguments of the first partial specialization, and
//     - the second function template has the same template parameters as the
//       second partial specialization and has a single function parameter
//       whose type is a class template specialization with the template
//       arguments of the second partial specialization.
//
// Rather than synthesize function templates, we merely perform the
// equivalent partial ordering by performing deduction directly on
// the template arguments of the class template partial
// specializations. This computation is slightly simpler than the
// general problem of function template partial ordering, because
// class template partial specializations are more constrained. We
// know that every template parameter is deducible from the class
// template partial specialization's template arguments, for
// example.
SmallVector<DeducedTemplateArgument, 4> Deduced;

// Determine whether P1 is at least as specialized as P2.
Deduced.resize(P2->getTemplateParameters()->size());
if (DeduceTemplateArgumentsByTypeMatch(S, P2->getTemplateParameters(),
                                       T2, T1, Info, Deduced, TDF_None,
                                       /*PartialOrdering=*/true))
  return false;

SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(),
                                             Deduced.end());
Sema::InstantiatingTemplate Inst(S, Info.getLocation(), P2, DeducedArgs,
                                 Info);
auto *TST1 = T1->castAs<TemplateSpecializationType>();
if (FinishTemplateArgumentDeduction(
        S, P2, /*IsPartialOrdering=*/true,
        TemplateArgumentList(TemplateArgumentList::OnStack,
                             TST1->template_arguments()),
        Deduced, Info))
  return false;

return true;
5102}

5104/// Returns the more specialized class template partial specialization
5105/// according to the rules of partial ordering of class template partial
5106/// specializations (C++ [temp.class.order]).
5107///
5108/// \param PS1 the first class template partial specialization
5109///
5110/// \param PS2 the second class template partial specialization
5111///
5112/// \returns the more specialized class template partial specialization. If
5113/// neither partial specialization is more specialized, returns NULL.
5114ClassTemplatePartialSpecializationDecl *
5115Sema::getMoreSpecializedPartialSpecialization(
                                ClassTemplatePartialSpecializationDecl *PS1,
                                ClassTemplatePartialSpecializationDecl *PS2,
                                            SourceLocation Loc) {
QualType PT1 = PS1->getInjectedSpecializationType();
QualType PT2 = PS2->getInjectedSpecializationType();

TemplateDeductionInfo Info(Loc);
bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info);
bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info);

if (Better1 == Better2)
  return nullptr;

return Better1 ? PS1 : PS2;
5130}

5132bool Sema::isMoreSpecializedThanPrimary(
  ClassTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) {
ClassTemplateDecl *Primary = Spec->getSpecializedTemplate();
QualType PrimaryT = Primary->getInjectedClassNameSpecialization();
QualType PartialT = Spec->getInjectedSpecializationType();
if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info))
  return false;
if (isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info)) {
  Info.clearSFINAEDiagnostic();
  return false;
}
return true;
5144}

5146VarTemplatePartialSpecializationDecl *
5147Sema::getMoreSpecializedPartialSpecialization(
  VarTemplatePartialSpecializationDecl *PS1,
  VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc) {
// Pretend the variable template specializations are class template
// specializations and form a fake injected class name type for comparison.
assert(PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() &&((PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate
() && "the partial specializations being compared should specialize"
 " the same template.") ? static_cast<void> (0) : __assert_fail
 ("PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() && \"the partial specializations being compared should specialize\" \" the same template.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5154, __PRETTY_FUNCTION__))
       "the partial specializations being compared should specialize"((PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate
() && "the partial specializations being compared should specialize"
 " the same template.") ? static_cast<void> (0) : __assert_fail
 ("PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() && \"the partial specializations being compared should specialize\" \" the same template.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5154, __PRETTY_FUNCTION__))
       " the same template.")((PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate
() && "the partial specializations being compared should specialize"
 " the same template.") ? static_cast<void> (0) : __assert_fail
 ("PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() && \"the partial specializations being compared should specialize\" \" the same template.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5154, __PRETTY_FUNCTION__));
TemplateName Name(PS1->getSpecializedTemplate());
TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
QualType PT1 = Context.getTemplateSpecializationType(
    CanonTemplate, PS1->getTemplateArgs().asArray());
QualType PT2 = Context.getTemplateSpecializationType(
    CanonTemplate, PS2->getTemplateArgs().asArray());

TemplateDeductionInfo Info(Loc);
bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info);
bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info);

if (Better1 == Better2)
  return nullptr;

return Better1 ? PS1 : PS2;
5170}

5172bool Sema::isMoreSpecializedThanPrimary(
  VarTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) {
TemplateDecl *Primary = Spec->getSpecializedTemplate();
// FIXME: Cache the injected template arguments rather than recomputing
// them for each partial specialization.
SmallVector<TemplateArgument, 8> PrimaryArgs;
Context.getInjectedTemplateArgs(Primary->getTemplateParameters(),
                                PrimaryArgs);

TemplateName CanonTemplate =
    Context.getCanonicalTemplateName(TemplateName(Primary));
QualType PrimaryT = Context.getTemplateSpecializationType(
    CanonTemplate, PrimaryArgs);
QualType PartialT = Context.getTemplateSpecializationType(
    CanonTemplate, Spec->getTemplateArgs().asArray());
if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info))
  return false;
if (isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info)) {
  Info.clearSFINAEDiagnostic();
  return false;
}
return true;
5194}

5196bool Sema::isTemplateTemplateParameterAtLeastAsSpecializedAs(
   TemplateParameterList *P, TemplateDecl *AArg, SourceLocation Loc) {
// C++1z [temp.arg.template]p4: (DR 150)
//   A template template-parameter P is at least as specialized as a
//   template template-argument A if, given the following rewrite to two
//   function templates...

// Rather than synthesize function templates, we merely perform the
// equivalent partial ordering by performing deduction directly on
// the template parameter lists of the template template parameters.
//
//   Given an invented class template X with the template parameter list of
//   A (including default arguments):
TemplateName X = Context.getCanonicalTemplateName(TemplateName(AArg));
TemplateParameterList *A = AArg->getTemplateParameters();

//    - Each function template has a single function parameter whose type is
//      a specialization of X with template arguments corresponding to the
//      template parameters from the respective function template
SmallVector<TemplateArgument, 8> AArgs;
Context.getInjectedTemplateArgs(A, AArgs);

// Check P's arguments against A's parameter list. This will fill in default
// template arguments as needed. AArgs are already correct by construction.
// We can't just use CheckTemplateIdType because that will expand alias
// templates.
SmallVector<TemplateArgument, 4> PArgs;
{
  SFINAETrap Trap(*this);

  Context.getInjectedTemplateArgs(P, PArgs);
  TemplateArgumentListInfo PArgList(P->getLAngleLoc(), P->getRAngleLoc());
  for (unsigned I = 0, N = P->size(); I != N; ++I) {
    // Unwrap packs that getInjectedTemplateArgs wrapped around pack
    // expansions, to form an "as written" argument list.
    TemplateArgument Arg = PArgs[I];
    if (Arg.getKind() == TemplateArgument::Pack) {
      assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion())((Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion
()) ? static_cast<void> (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion()"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5233, __PRETTY_FUNCTION__));
      Arg = *Arg.pack_begin();
    }
    PArgList.addArgument(getTrivialTemplateArgumentLoc(
        Arg, QualType(), P->getParam(I)->getLocation()));
  }
  PArgs.clear();

  // C++1z [temp.arg.template]p3:
  //   If the rewrite produces an invalid type, then P is not at least as
  //   specialized as A.
  if (CheckTemplateArgumentList(AArg, Loc, PArgList, false, PArgs) ||
      Trap.hasErrorOccurred())
    return false;
}

QualType AType = Context.getTemplateSpecializationType(X, AArgs);
QualType PType = Context.getTemplateSpecializationType(X, PArgs);

//   ... the function template corresponding to P is at least as specialized
//   as the function template corresponding to A according to the partial
//   ordering rules for function templates.
TemplateDeductionInfo Info(Loc, A->getDepth());
return isAtLeastAsSpecializedAs(*this, PType, AType, AArg, Info);
5257}

5259/// Mark the template parameters that are used by the given
5260/// expression.
5261static void
5262MarkUsedTemplateParameters(ASTContext &Ctx,
                         const Expr *E,
                         bool OnlyDeduced,
                         unsigned Depth,
                         llvm::SmallBitVector &Used) {
// We can deduce from a pack expansion.
if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E))
  E = Expansion->getPattern();

// Skip through any implicit casts we added while type-checking, and any
// substitutions performed by template alias expansion.
while (true) {
  if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
    E = ICE->getSubExpr();
  else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(E))
    E = CE->getSubExpr();
  else if (const SubstNonTypeTemplateParmExpr *Subst =
             dyn_cast<SubstNonTypeTemplateParmExpr>(E))
    E = Subst->getReplacement();
  else
    break;
}

// FIXME: if !OnlyDeduced, we have to walk the whole subexpression to
// find other occurrences of template parameters.
const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
if (!DRE)
  return;

const NonTypeTemplateParmDecl *NTTP
  = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
if (!NTTP)
  return;

if (NTTP->getDepth() == Depth)
  Used[NTTP->getIndex()] = true;

// In C++17 mode, additional arguments may be deduced from the type of a
// non-type argument.
if (Ctx.getLangOpts().CPlusPlus17)
  MarkUsedTemplateParameters(Ctx, NTTP->getType(), OnlyDeduced, Depth, Used);
5303}

5305/// Mark the template parameters that are used by the given
5306/// nested name specifier.
5307static void
5308MarkUsedTemplateParameters(ASTContext &Ctx,
                         NestedNameSpecifier *NNS,
                         bool OnlyDeduced,
                         unsigned Depth,
                         llvm::SmallBitVector &Used) {
if (!NNS)
  return;

MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth,
                           Used);
MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0),
                           OnlyDeduced, Depth, Used);
5320}

5322/// Mark the template parameters that are used by the given
5323/// template name.
5324static void
5325MarkUsedTemplateParameters(ASTContext &Ctx,
                         TemplateName Name,
                         bool OnlyDeduced,
                         unsigned Depth,
                         llvm::SmallBitVector &Used) {
if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
  if (TemplateTemplateParmDecl *TTP
        = dyn_cast<TemplateTemplateParmDecl>(Template)) {
    if (TTP->getDepth() == Depth)
      Used[TTP->getIndex()] = true;
  }
  return;
}

if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName())
  MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced,
                             Depth, Used);
if (DependentTemplateName *DTN = Name.getAsDependentTemplateName())
  MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced,
                             Depth, Used);
5345}

5347/// Mark the template parameters that are used by the given
5348/// type.
5349static void
5350MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
                         bool OnlyDeduced,
                         unsigned Depth,
                         llvm::SmallBitVector &Used) {
if (T.isNull())
  return;

// Non-dependent types have nothing deducible
if (!T->isDependentType())
  return;

T = Ctx.getCanonicalType(T);
switch (T->getTypeClass()) {
case Type::Pointer:
  MarkUsedTemplateParameters(Ctx,
                             cast<PointerType>(T)->getPointeeType(),
                             OnlyDeduced,
                             Depth,
                             Used);
  break;

case Type::BlockPointer:
  MarkUsedTemplateParameters(Ctx,
                             cast<BlockPointerType>(T)->getPointeeType(),
                             OnlyDeduced,
                             Depth,
                             Used);
  break;

case Type::LValueReference:
case Type::RValueReference:
  MarkUsedTemplateParameters(Ctx,
                             cast<ReferenceType>(T)->getPointeeType(),
                             OnlyDeduced,
                             Depth,
                             Used);
  break;

case Type::MemberPointer: {
  const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr());
  MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced,
                             Depth, Used);
  MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0),
                             OnlyDeduced, Depth, Used);
  break;
}

case Type::DependentSizedArray:
  MarkUsedTemplateParameters(Ctx,
                             cast<DependentSizedArrayType>(T)->getSizeExpr(),
                             OnlyDeduced, Depth, Used);
  // Fall through to check the element type
  LLVM_FALLTHROUGH[[gnu::fallthrough]];

case Type::ConstantArray:
case Type::IncompleteArray:
  MarkUsedTemplateParameters(Ctx,
                             cast<ArrayType>(T)->getElementType(),
                             OnlyDeduced, Depth, Used);
  break;

case Type::Vector:
case Type::ExtVector:
  MarkUsedTemplateParameters(Ctx,
                             cast<VectorType>(T)->getElementType(),
                             OnlyDeduced, Depth, Used);
  break;

case Type::DependentVector: {
  const auto *VecType = cast<DependentVectorType>(T);
  MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced,
                             Depth, Used);
  MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, Depth,
                             Used);
  break;
}
case Type::DependentSizedExtVector: {
  const DependentSizedExtVectorType *VecType
    = cast<DependentSizedExtVectorType>(T);
  MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced,
                             Depth, Used);
  MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced,
                             Depth, Used);
  break;
}

case Type::DependentAddressSpace: {
  const DependentAddressSpaceType *DependentASType =
      cast<DependentAddressSpaceType>(T);
  MarkUsedTemplateParameters(Ctx, DependentASType->getPointeeType(),
                             OnlyDeduced, Depth, Used);
  MarkUsedTemplateParameters(Ctx,
                             DependentASType->getAddrSpaceExpr(),
                             OnlyDeduced, Depth, Used);
  break;
}

case Type::FunctionProto: {
  const FunctionProtoType *Proto = cast<FunctionProtoType>(T);
  MarkUsedTemplateParameters(Ctx, Proto->getReturnType(), OnlyDeduced, Depth,
                             Used);
  for (unsigned I = 0, N = Proto->getNumParams(); I != N; ++I) {
    // C++17 [temp.deduct.type]p5:
    //   The non-deduced contexts are: [...]
    //   -- A function parameter pack that does not occur at the end of the
    //      parameter-declaration-list.
    if (!OnlyDeduced || I + 1 == N ||
        !Proto->getParamType(I)->getAs<PackExpansionType>()) {
      MarkUsedTemplateParameters(Ctx, Proto->getParamType(I), OnlyDeduced,
                                 Depth, Used);
    } else {
      // FIXME: C++17 [temp.deduct.call]p1:
      //   When a function parameter pack appears in a non-deduced context,
      //   the type of that pack is never deduced.
      //
      // We should also track a set of "never deduced" parameters, and
      // subtract that from the list of deduced parameters after marking.
    }
  }
  if (auto *E = Proto->getNoexceptExpr())
    MarkUsedTemplateParameters(Ctx, E, OnlyDeduced, Depth, Used);
  break;
}

case Type::TemplateTypeParm: {
  const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T);
  if (TTP->getDepth() == Depth)
    Used[TTP->getIndex()] = true;
  break;
}

case Type::SubstTemplateTypeParmPack: {
  const SubstTemplateTypeParmPackType *Subst
    = cast<SubstTemplateTypeParmPackType>(T);
  MarkUsedTemplateParameters(Ctx,
                             QualType(Subst->getReplacedParameter(), 0),
                             OnlyDeduced, Depth, Used);
  MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(),
                             OnlyDeduced, Depth, Used);
  break;
}

case Type::InjectedClassName:
  T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
  LLVM_FALLTHROUGH[[gnu::fallthrough]];

case Type::TemplateSpecialization: {
  const TemplateSpecializationType *Spec
    = cast<TemplateSpecializationType>(T);
  MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced,
                             Depth, Used);

  // C++0x [temp.deduct.type]p9:
  //   If the template argument list of P contains a pack expansion that is
  //   not the last template argument, the entire template argument list is a
  //   non-deduced context.
  if (OnlyDeduced &&
      hasPackExpansionBeforeEnd(Spec->template_arguments()))
    break;

  for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
    MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth,
                               Used);
  break;
}

case Type::Complex:
  if (!OnlyDeduced)
    MarkUsedTemplateParameters(Ctx,
                               cast<ComplexType>(T)->getElementType(),
                               OnlyDeduced, Depth, Used);
  break;

case Type::Atomic:
  if (!OnlyDeduced)
    MarkUsedTemplateParameters(Ctx,
                               cast<AtomicType>(T)->getValueType(),
                               OnlyDeduced, Depth, Used);
  break;

case Type::DependentName:
  if (!OnlyDeduced)
    MarkUsedTemplateParameters(Ctx,
                               cast<DependentNameType>(T)->getQualifier(),
                               OnlyDeduced, Depth, Used);
  break;

case Type::DependentTemplateSpecialization: {
  // C++14 [temp.deduct.type]p5:
  //   The non-deduced contexts are:
  //     -- The nested-name-specifier of a type that was specified using a
  //        qualified-id
  //
  // C++14 [temp.deduct.type]p6:
  //   When a type name is specified in a way that includes a non-deduced
  //   context, all of the types that comprise that type name are also
  //   non-deduced.
  if (OnlyDeduced)
    break;

  const DependentTemplateSpecializationType *Spec
    = cast<DependentTemplateSpecializationType>(T);

  MarkUsedTemplateParameters(Ctx, Spec->getQualifier(),
                             OnlyDeduced, Depth, Used);

  for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
    MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth,
                               Used);
  break;
}

case Type::TypeOf:
  if (!OnlyDeduced)
    MarkUsedTemplateParameters(Ctx,
                               cast<TypeOfType>(T)->getUnderlyingType(),
                               OnlyDeduced, Depth, Used);
  break;

case Type::TypeOfExpr:
  if (!OnlyDeduced)
    MarkUsedTemplateParameters(Ctx,
                               cast<TypeOfExprType>(T)->getUnderlyingExpr(),
                               OnlyDeduced, Depth, Used);
  break;

case Type::Decltype:
  if (!OnlyDeduced)
    MarkUsedTemplateParameters(Ctx,
                               cast<DecltypeType>(T)->getUnderlyingExpr(),
                               OnlyDeduced, Depth, Used);
  break;

case Type::UnaryTransform:
  if (!OnlyDeduced)
    MarkUsedTemplateParameters(Ctx,
                               cast<UnaryTransformType>(T)->getUnderlyingType(),
                               OnlyDeduced, Depth, Used);
  break;

case Type::PackExpansion:
  MarkUsedTemplateParameters(Ctx,
                             cast<PackExpansionType>(T)->getPattern(),
                             OnlyDeduced, Depth, Used);
  break;

case Type::Auto:
case Type::DeducedTemplateSpecialization:
  MarkUsedTemplateParameters(Ctx,
                             cast<DeducedType>(T)->getDeducedType(),
                             OnlyDeduced, Depth, Used);
  break;

// None of these types have any template parameters in them.
case Type::Builtin:
case Type::VariableArray:
case Type::FunctionNoProto:
case Type::Record:
case Type::Enum:
case Type::ObjCInterface:
case Type::ObjCObject:
case Type::ObjCObjectPointer:
case Type::UnresolvedUsing:
case Type::Pipe:
5614#define TYPE(Class, Base)
5615#define ABSTRACT_TYPE(Class, Base)
5616#define DEPENDENT_TYPE(Class, Base)
5617#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
5618#include "clang/AST/TypeNodes.inc"
  break;
}
5621}

5623/// Mark the template parameters that are used by this
5624/// template argument.
5625static void
5626MarkUsedTemplateParameters(ASTContext &Ctx,
                         const TemplateArgument &TemplateArg,
                         bool OnlyDeduced,
                         unsigned Depth,
                         llvm::SmallBitVector &Used) {
switch (TemplateArg.getKind()) {
case TemplateArgument::Null:
case TemplateArgument::Integral:
case TemplateArgument::Declaration:
  break;

case TemplateArgument::NullPtr:
  MarkUsedTemplateParameters(Ctx, TemplateArg.getNullPtrType(), OnlyDeduced,
                             Depth, Used);
  break;

case TemplateArgument::Type:
  MarkUsedTemplateParameters(Ctx, TemplateArg.getAsType(), OnlyDeduced,
                             Depth, Used);
  break;

case TemplateArgument::Template:
case TemplateArgument::TemplateExpansion:
  MarkUsedTemplateParameters(Ctx,
                             TemplateArg.getAsTemplateOrTemplatePattern(),
                             OnlyDeduced, Depth, Used);
  break;

case TemplateArgument::Expression:
  MarkUsedTemplateParameters(Ctx, TemplateArg.getAsExpr(), OnlyDeduced,
                             Depth, Used);
  break;

case TemplateArgument::Pack:
  for (const auto &P : TemplateArg.pack_elements())
    MarkUsedTemplateParameters(Ctx, P, OnlyDeduced, Depth, Used);
  break;
}
5664}

5666/// Mark which template parameters can be deduced from a given
5667/// template argument list.
5668///
5669/// \param TemplateArgs the template argument list from which template
5670/// parameters will be deduced.
5671///
5672/// \param Used a bit vector whose elements will be set to \c true
5673/// to indicate when the corresponding template parameter will be
5674/// deduced.
5675void
5676Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
                               bool OnlyDeduced, unsigned Depth,
                               llvm::SmallBitVector &Used) {
// C++0x [temp.deduct.type]p9:
//   If the template argument list of P contains a pack expansion that is not
//   the last template argument, the entire template argument list is a
//   non-deduced context.
if (OnlyDeduced &&
    hasPackExpansionBeforeEnd(TemplateArgs.asArray()))
  return;

for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
  ::MarkUsedTemplateParameters(Context, TemplateArgs[I], OnlyDeduced,
                               Depth, Used);
5690}

5692/// Marks all of the template parameters that will be deduced by a
5693/// call to the given function template.
5694void Sema::MarkDeducedTemplateParameters(
  ASTContext &Ctx, const FunctionTemplateDecl *FunctionTemplate,
  llvm::SmallBitVector &Deduced) {
TemplateParameterList *TemplateParams
  = FunctionTemplate->getTemplateParameters();
Deduced.clear();
Deduced.resize(TemplateParams->size());

FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I)
  ::MarkUsedTemplateParameters(Ctx, Function->getParamDecl(I)->getType(),
                               true, TemplateParams->getDepth(), Deduced);
5706}

5708bool hasDeducibleTemplateParameters(Sema &S,
                                  FunctionTemplateDecl *FunctionTemplate,
                                  QualType T) {
if (!T->isDependentType())
  return false;

TemplateParameterList *TemplateParams
  = FunctionTemplate->getTemplateParameters();
llvm::SmallBitVector Deduced(TemplateParams->size());
::MarkUsedTemplateParameters(S.Context, T, true, TemplateParams->getDepth(),
                             Deduced);

return Deduced.any();
5721}

←

/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h

1//===--- Sema.h - Semantic Analysis & AST Building --------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the Sema class, which performs semantic analysis and
10// builds ASTs.
11//
12//===----------------------------------------------------------------------===//

14#ifndef LLVM_CLANG_SEMA_SEMA_H
15#define LLVM_CLANG_SEMA_SEMA_H

17#include "clang/AST/Attr.h"
18#include "clang/AST/Availability.h"
19#include "clang/AST/ComparisonCategories.h"
20#include "clang/AST/DeclTemplate.h"
21#include "clang/AST/DeclarationName.h"
22#include "clang/AST/Expr.h"
23#include "clang/AST/ExprCXX.h"
24#include "clang/AST/ExprObjC.h"
25#include "clang/AST/ExternalASTSource.h"
26#include "clang/AST/LocInfoType.h"
27#include "clang/AST/MangleNumberingContext.h"
28#include "clang/AST/NSAPI.h"
29#include "clang/AST/PrettyPrinter.h"
30#include "clang/AST/StmtCXX.h"
31#include "clang/AST/TypeLoc.h"
32#include "clang/AST/TypeOrdering.h"
33#include "clang/Basic/ExpressionTraits.h"
34#include "clang/Basic/Module.h"
35#include "clang/Basic/OpenMPKinds.h"
36#include "clang/Basic/PragmaKinds.h"
37#include "clang/Basic/Specifiers.h"
38#include "clang/Basic/TemplateKinds.h"
39#include "clang/Basic/TypeTraits.h"
40#include "clang/Sema/AnalysisBasedWarnings.h"
41#include "clang/Sema/CleanupInfo.h"
42#include "clang/Sema/DeclSpec.h"
43#include "clang/Sema/ExternalSemaSource.h"
44#include "clang/Sema/IdentifierResolver.h"
45#include "clang/Sema/ObjCMethodList.h"
46#include "clang/Sema/Ownership.h"
47#include "clang/Sema/Scope.h"
48#include "clang/Sema/TypoCorrection.h"
49#include "clang/Sema/Weak.h"
50#include "llvm/ADT/ArrayRef.h"
51#include "llvm/ADT/Optional.h"
52#include "llvm/ADT/SetVector.h"
53#include "llvm/ADT/SmallBitVector.h"
54#include "llvm/ADT/SmallPtrSet.h"
55#include "llvm/ADT/SmallVector.h"
56#include "llvm/ADT/TinyPtrVector.h"
57#include <deque>
58#include <memory>
59#include <string>
60#include <tuple>
61#include <vector>

63namespace llvm {
class APSInt;
template <typename ValueT> struct DenseMapInfo;
template <typename ValueT, typename ValueInfoT> class DenseSet;
class SmallBitVector;
struct InlineAsmIdentifierInfo;
69}

71namespace clang {
class ADLResult;
class ASTConsumer;
class ASTContext;
class ASTMutationListener;
class ASTReader;
class ASTWriter;
class ArrayType;
class ParsedAttr;
class BindingDecl;
class BlockDecl;
class CapturedDecl;
class CXXBasePath;
class CXXBasePaths;
class CXXBindTemporaryExpr;
typedef SmallVector<CXXBaseSpecifier*, 4> CXXCastPath;
class CXXConstructorDecl;
class CXXConversionDecl;
class CXXDeleteExpr;
class CXXDestructorDecl;
class CXXFieldCollector;
class CXXMemberCallExpr;
class CXXMethodDecl;
class CXXScopeSpec;
class CXXTemporary;
class CXXTryStmt;
class CallExpr;
class ClassTemplateDecl;
class ClassTemplatePartialSpecializationDecl;
class ClassTemplateSpecializationDecl;
class VarTemplatePartialSpecializationDecl;
class CodeCompleteConsumer;
class CodeCompletionAllocator;
class CodeCompletionTUInfo;
class CodeCompletionResult;
class CoroutineBodyStmt;
class Decl;
class DeclAccessPair;
class DeclContext;
class DeclRefExpr;
class DeclaratorDecl;
class DeducedTemplateArgument;
class DependentDiagnostic;
class DesignatedInitExpr;
class Designation;
class EnableIfAttr;
class EnumConstantDecl;
class Expr;
class ExtVectorType;
class FormatAttr;
class FriendDecl;
class FunctionDecl;
class FunctionProtoType;
class FunctionTemplateDecl;
class ImplicitConversionSequence;
typedef MutableArrayRef<ImplicitConversionSequence> ConversionSequenceList;
class InitListExpr;
class InitializationKind;
class InitializationSequence;
class InitializedEntity;
class IntegerLiteral;
class LabelStmt;
class LambdaExpr;
class LangOptions;
class LocalInstantiationScope;
class LookupResult;
class MacroInfo;
typedef ArrayRef<std::pair<IdentifierInfo *, SourceLocation>> ModuleIdPath;
class ModuleLoader;
class MultiLevelTemplateArgumentList;
class NamedDecl;
class ObjCCategoryDecl;
class ObjCCategoryImplDecl;
class ObjCCompatibleAliasDecl;
class ObjCContainerDecl;
class ObjCImplDecl;
class ObjCImplementationDecl;
class ObjCInterfaceDecl;
class ObjCIvarDecl;
template <class T> class ObjCList;
class ObjCMessageExpr;
class ObjCMethodDecl;
class ObjCPropertyDecl;
class ObjCProtocolDecl;
class OMPThreadPrivateDecl;
class OMPRequiresDecl;
class OMPDeclareReductionDecl;
class OMPDeclareSimdDecl;
class OMPClause;
struct OMPVarListLocTy;
struct OverloadCandidate;
class OverloadCandidateSet;
class OverloadExpr;
class ParenListExpr;
class ParmVarDecl;
class Preprocessor;
class PseudoDestructorTypeStorage;
class PseudoObjectExpr;
class QualType;
class StandardConversionSequence;
class Stmt;
class StringLiteral;
class SwitchStmt;
class TemplateArgument;
class TemplateArgumentList;
class TemplateArgumentLoc;
class TemplateDecl;
class TemplateInstantiationCallback;
class TemplateParameterList;
class TemplatePartialOrderingContext;
class TemplateTemplateParmDecl;
class Token;
class TypeAliasDecl;
class TypedefDecl;
class TypedefNameDecl;
class TypeLoc;
class TypoCorrectionConsumer;
class UnqualifiedId;
class UnresolvedLookupExpr;
class UnresolvedMemberExpr;
class UnresolvedSetImpl;
class UnresolvedSetIterator;
class UsingDecl;
class UsingShadowDecl;
class ValueDecl;
class VarDecl;
class VarTemplateSpecializationDecl;
class VisibilityAttr;
class VisibleDeclConsumer;
class IndirectFieldDecl;
struct DeductionFailureInfo;
class TemplateSpecCandidateSet;

204namespace sema {
class AccessedEntity;
class BlockScopeInfo;
class Capture;
class CapturedRegionScopeInfo;
class CapturingScopeInfo;
class CompoundScopeInfo;
class DelayedDiagnostic;
class DelayedDiagnosticPool;
class FunctionScopeInfo;
class LambdaScopeInfo;
class PossiblyUnreachableDiag;
class SemaPPCallbacks;
class TemplateDeductionInfo;
218}

220namespace threadSafety {
class BeforeSet;
void threadSafetyCleanup(BeforeSet* Cache);
223}

225// FIXME: No way to easily map from TemplateTypeParmTypes to
226// TemplateTypeParmDecls, so we have this horrible PointerUnion.
227typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType*, NamedDecl*>,
                SourceLocation> UnexpandedParameterPack;

230/// Describes whether we've seen any nullability information for the given
231/// file.
232struct FileNullability {
/// The first pointer declarator (of any pointer kind) in the file that does
/// not have a corresponding nullability annotation.
SourceLocation PointerLoc;

/// The end location for the first pointer declarator in the file. Used for
/// placing fix-its.
SourceLocation PointerEndLoc;

/// Which kind of pointer declarator we saw.
uint8_t PointerKind;

/// Whether we saw any type nullability annotations in the given file.
bool SawTypeNullability = false;
246};

248/// A mapping from file IDs to a record of whether we've seen nullability
249/// information in that file.
250class FileNullabilityMap {
/// A mapping from file IDs to the nullability information for each file ID.
llvm::DenseMap<FileID, FileNullability> Map;

/// A single-element cache based on the file ID.
struct {
  FileID File;
  FileNullability Nullability;
} Cache;

260public:
FileNullability &operator[](FileID file) {
  // Check the single-element cache.
  if (file == Cache.File)
    return Cache.Nullability;

  // It's not in the single-element cache; flush the cache if we have one.
  if (!Cache.File.isInvalid()) {
    Map[Cache.File] = Cache.Nullability;
  }

  // Pull this entry into the cache.
  Cache.File = file;
  Cache.Nullability = Map[file];
  return Cache.Nullability;
}
276};

278/// Keeps track of expected type during expression parsing. The type is tied to
279/// a particular token, all functions that update or consume the type take a
280/// start location of the token they are looking at as a parameter. This allows
281/// to avoid updating the type on hot paths in the parser.
282class PreferredTypeBuilder {
283public:
PreferredTypeBuilder() = default;
explicit PreferredTypeBuilder(QualType Type) : Type(Type) {}

void enterCondition(Sema &S, SourceLocation Tok);
void enterReturn(Sema &S, SourceLocation Tok);
void enterVariableInit(SourceLocation Tok, Decl *D);
/// Computing a type for the function argument may require running
/// overloading, so we postpone its computation until it is actually needed.
///
/// Clients should be very careful when using this funciton, as it stores a
/// function_ref, clients should make sure all calls to get() with the same
/// location happen while function_ref is alive.
void enterFunctionArgument(SourceLocation Tok,
                           llvm::function_ref<QualType()> ComputeType);

void enterParenExpr(SourceLocation Tok, SourceLocation LParLoc);
void enterUnary(Sema &S, SourceLocation Tok, tok::TokenKind OpKind,
                SourceLocation OpLoc);
void enterBinary(Sema &S, SourceLocation Tok, Expr *LHS, tok::TokenKind Op);
void enterMemAccess(Sema &S, SourceLocation Tok, Expr *Base);
void enterSubscript(Sema &S, SourceLocation Tok, Expr *LHS);
/// Handles all type casts, including C-style cast, C++ casts, etc.
void enterTypeCast(SourceLocation Tok, QualType CastType);

QualType get(SourceLocation Tok) const {
  if (Tok != ExpectedLoc)
    return QualType();
  if (!Type.isNull())
    return Type;
  if (ComputeType)
    return ComputeType();
  return QualType();
}

318private:
/// Start position of a token for which we store expected type.
SourceLocation ExpectedLoc;
/// Expected type for a token starting at ExpectedLoc.
QualType Type;
/// A function to compute expected type at ExpectedLoc. It is only considered
/// if Type is null.
llvm::function_ref<QualType()> ComputeType;
326};

328/// Sema - This implements semantic analysis and AST building for C.
329class Sema {
Sema(const Sema &) = delete;
void operator=(const Sema &) = delete;

///Source of additional semantic information.
ExternalSemaSource *ExternalSource;

///Whether Sema has generated a multiplexer and has to delete it.
bool isMultiplexExternalSource;

static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);

bool isVisibleSlow(const NamedDecl *D);

/// Determine whether two declarations should be linked together, given that
/// the old declaration might not be visible and the new declaration might
/// not have external linkage.
bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
                                  const NamedDecl *New) {
  if (isVisible(Old))
   return true;
  // See comment in below overload for why it's safe to compute the linkage
  // of the new declaration here.
  if (New->isExternallyDeclarable()) {
    assert(Old->isExternallyDeclarable() &&((Old->isExternallyDeclarable() && "should not have found a non-externally-declarable previous decl"
) ? static_cast<void> (0) : __assert_fail ("Old->isExternallyDeclarable() && \"should not have found a non-externally-declarable previous decl\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 354, __PRETTY_FUNCTION__))
           "should not have found a non-externally-declarable previous decl")((Old->isExternallyDeclarable() && "should not have found a non-externally-declarable previous decl"
) ? static_cast<void> (0) : __assert_fail ("Old->isExternallyDeclarable() && \"should not have found a non-externally-declarable previous decl\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 354, __PRETTY_FUNCTION__));
    return true;
  }
  return false;
}
bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);

void setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
                                    QualType ResultTy,
                                    ArrayRef<QualType> Args);

365public:
typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
typedef OpaquePtr<TemplateName> TemplateTy;
typedef OpaquePtr<QualType> TypeTy;

OpenCLOptions OpenCLFeatures;
FPOptions FPFeatures;

const LangOptions &LangOpts;
Preprocessor &PP;
ASTContext &Context;
ASTConsumer &Consumer;
DiagnosticsEngine &Diags;
SourceManager &SourceMgr;

/// Flag indicating whether or not to collect detailed statistics.
bool CollectStats;

/// Code-completion consumer.
CodeCompleteConsumer *CodeCompleter;

/// CurContext - This is the current declaration context of parsing.
DeclContext *CurContext;

/// Generally null except when we temporarily switch decl contexts,
/// like in \see ActOnObjCTemporaryExitContainerContext.
DeclContext *OriginalLexicalContext;

/// VAListTagName - The declaration name corresponding to __va_list_tag.
/// This is used as part of a hack to omit that class from ADL results.
DeclarationName VAListTagName;

bool MSStructPragmaOn; // True when \#pragma ms_struct on

/// Controls member pointer representation format under the MS ABI.
LangOptions::PragmaMSPointersToMembersKind
    MSPointerToMemberRepresentationMethod;

/// Stack of active SEH __finally scopes.  Can be empty.
SmallVector<Scope*, 2> CurrentSEHFinally;

/// Source location for newly created implicit MSInheritanceAttrs
SourceLocation ImplicitMSInheritanceAttrLoc;

/// Holds TypoExprs that are created from `createDelayedTypo`. This is used by
/// `TransformTypos` in order to keep track of any TypoExprs that are created
/// recursively during typo correction and wipe them away if the correction
/// fails.
llvm::SmallVector<TypoExpr *, 2> TypoExprs;

/// pragma clang section kind
enum PragmaClangSectionKind {
  PCSK_Invalid      = 0,
  PCSK_BSS          = 1,
  PCSK_Data         = 2,
  PCSK_Rodata       = 3,
  PCSK_Text         = 4
 };

enum PragmaClangSectionAction {
  PCSA_Set     = 0,
  PCSA_Clear   = 1
};

struct PragmaClangSection {
  std::string SectionName;
  bool Valid = false;
  SourceLocation PragmaLocation;

  void Act(SourceLocation PragmaLocation,
           PragmaClangSectionAction Action,
           StringLiteral* Name);
 };

 PragmaClangSection PragmaClangBSSSection;
 PragmaClangSection PragmaClangDataSection;
 PragmaClangSection PragmaClangRodataSection;
 PragmaClangSection PragmaClangTextSection;

enum PragmaMsStackAction {
  PSK_Reset     = 0x0,                // #pragma ()
  PSK_Set       = 0x1,                // #pragma (value)
  PSK_Push      = 0x2,                // #pragma (push[, id])
  PSK_Pop       = 0x4,                // #pragma (pop[, id])
  PSK_Show      = 0x8,                // #pragma (show) -- only for "pack"!
  PSK_Push_Set  = PSK_Push | PSK_Set, // #pragma (push[, id], value)
  PSK_Pop_Set   = PSK_Pop | PSK_Set,  // #pragma (pop[, id], value)
};

template<typename ValueType>
struct PragmaStack {
  struct Slot {
    llvm::StringRef StackSlotLabel;
    ValueType Value;
    SourceLocation PragmaLocation;
    SourceLocation PragmaPushLocation;
    Slot(llvm::StringRef StackSlotLabel, ValueType Value,
         SourceLocation PragmaLocation, SourceLocation PragmaPushLocation)
        : StackSlotLabel(StackSlotLabel), Value(Value),
          PragmaLocation(PragmaLocation),
          PragmaPushLocation(PragmaPushLocation) {}
  };
  void Act(SourceLocation PragmaLocation,
           PragmaMsStackAction Action,
           llvm::StringRef StackSlotLabel,
           ValueType Value);

  // MSVC seems to add artificial slots to #pragma stacks on entering a C++
  // method body to restore the stacks on exit, so it works like this:
  //
  //   struct S {
  //     #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
  //     void Method {}
  //     #pragma <name>(pop, InternalPragmaSlot)
  //   };
  //
  // It works even with #pragma vtordisp, although MSVC doesn't support
  //   #pragma vtordisp(push [, id], n)
  // syntax.
  //
  // Push / pop a named sentinel slot.
  void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
    assert((Action == PSK_Push || Action == PSK_Pop) &&(((Action == PSK_Push || Action == PSK_Pop) && "Can only push / pop #pragma stack sentinels!"
) ? static_cast<void> (0) : __assert_fail ("(Action == PSK_Push || Action == PSK_Pop) && \"Can only push / pop #pragma stack sentinels!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 488, __PRETTY_FUNCTION__))
           "Can only push / pop #pragma stack sentinels!")(((Action == PSK_Push || Action == PSK_Pop) && "Can only push / pop #pragma stack sentinels!"
) ? static_cast<void> (0) : __assert_fail ("(Action == PSK_Push || Action == PSK_Pop) && \"Can only push / pop #pragma stack sentinels!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 488, __PRETTY_FUNCTION__));
    Act(CurrentPragmaLocation, Action, Label, CurrentValue);
  }

  // Constructors.
  explicit PragmaStack(const ValueType &Default)
      : DefaultValue(Default), CurrentValue(Default) {}

  bool hasValue() const { return CurrentValue != DefaultValue; }

  SmallVector<Slot, 2> Stack;
  ValueType DefaultValue; // Value used for PSK_Reset action.
  ValueType CurrentValue;
  SourceLocation CurrentPragmaLocation;
};
// FIXME: We should serialize / deserialize these if they occur in a PCH (but
// we shouldn't do so if they're in a module).

/// Whether to insert vtordisps prior to virtual bases in the Microsoft
/// C++ ABI.  Possible values are 0, 1, and 2, which mean:
///
/// 0: Suppress all vtordisps
/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
///    structors
/// 2: Always insert vtordisps to support RTTI on partially constructed
///    objects
PragmaStack<MSVtorDispAttr::Mode> VtorDispStack;
// #pragma pack.
// Sentinel to represent when the stack is set to mac68k alignment.
static const unsigned kMac68kAlignmentSentinel = ~0U;
PragmaStack<unsigned> PackStack;
// The current #pragma pack values and locations at each #include.
struct PackIncludeState {
  unsigned CurrentValue;
  SourceLocation CurrentPragmaLocation;
  bool HasNonDefaultValue, ShouldWarnOnInclude;
};
SmallVector<PackIncludeState, 8> PackIncludeStack;
// Segment #pragmas.
PragmaStack<StringLiteral *> DataSegStack;
PragmaStack<StringLiteral *> BSSSegStack;
PragmaStack<StringLiteral *> ConstSegStack;
PragmaStack<StringLiteral *> CodeSegStack;

// RAII object to push / pop sentinel slots for all MS #pragma stacks.
// Actions should be performed only if we enter / exit a C++ method body.
class PragmaStackSentinelRAII {
public:
  PragmaStackSentinelRAII(Sema &S, StringRef SlotLabel, bool ShouldAct);
  ~PragmaStackSentinelRAII();

private:
  Sema &S;
  StringRef SlotLabel;
  bool ShouldAct;
};

/// A mapping that describes the nullability we've seen in each header file.
FileNullabilityMap NullabilityMap;

/// Last section used with #pragma init_seg.
StringLiteral *CurInitSeg;
SourceLocation CurInitSegLoc;

/// VisContext - Manages the stack for \#pragma GCC visibility.
void *VisContext; // Really a "PragmaVisStack*"

/// This an attribute introduced by \#pragma clang attribute.
struct PragmaAttributeEntry {
  SourceLocation Loc;
  ParsedAttr *Attribute;
  SmallVector<attr::SubjectMatchRule, 4> MatchRules;
  bool IsUsed;
};

/// A push'd group of PragmaAttributeEntries.
struct PragmaAttributeGroup {
  /// The location of the push attribute.
  SourceLocation Loc;
  /// The namespace of this push group.
  const IdentifierInfo *Namespace;
  SmallVector<PragmaAttributeEntry, 2> Entries;
};

SmallVector<PragmaAttributeGroup, 2> PragmaAttributeStack;

/// The declaration that is currently receiving an attribute from the
/// #pragma attribute stack.
const Decl *PragmaAttributeCurrentTargetDecl;

/// This represents the last location of a "#pragma clang optimize off"
/// directive if such a directive has not been closed by an "on" yet. If
/// optimizations are currently "on", this is set to an invalid location.
SourceLocation OptimizeOffPragmaLocation;

/// Flag indicating if Sema is building a recovery call expression.
///
/// This flag is used to avoid building recovery call expressions
/// if Sema is already doing so, which would cause infinite recursions.
bool IsBuildingRecoveryCallExpr;

/// Used to control the generation of ExprWithCleanups.
CleanupInfo Cleanup;

/// ExprCleanupObjects - This is the stack of objects requiring
/// cleanup that are created by the current full expression.  The
/// element type here is ExprWithCleanups::Object.
SmallVector<BlockDecl*, 8> ExprCleanupObjects;

/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
/// to a variable (constant) that may or may not be odr-used in this Expr, and
/// we won't know until all lvalue-to-rvalue and discarded value conversions
/// have been applied to all subexpressions of the enclosing full expression.
/// This is cleared at the end of each full expression.
using MaybeODRUseExprSet = llvm::SmallPtrSet<Expr *, 2>;
MaybeODRUseExprSet MaybeODRUseExprs;

std::unique_ptr<sema::FunctionScopeInfo> CachedFunctionScope;

/// Stack containing information about each of the nested
/// function, block, and method scopes that are currently active.
SmallVector<sema::FunctionScopeInfo *, 4> FunctionScopes;

typedef LazyVector<TypedefNameDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadExtVectorDecls, 2, 2>
  ExtVectorDeclsType;

/// ExtVectorDecls - This is a list all the extended vector types. This allows
/// us to associate a raw vector type with one of the ext_vector type names.
/// This is only necessary for issuing pretty diagnostics.
ExtVectorDeclsType ExtVectorDecls;

/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
std::unique_ptr<CXXFieldCollector> FieldCollector;

typedef llvm::SmallSetVector<NamedDecl *, 16> NamedDeclSetType;

/// Set containing all declared private fields that are not used.
NamedDeclSetType UnusedPrivateFields;

/// Set containing all typedefs that are likely unused.
llvm::SmallSetVector<const TypedefNameDecl *, 4>
    UnusedLocalTypedefNameCandidates;

/// Delete-expressions to be analyzed at the end of translation unit
///
/// This list contains class members, and locations of delete-expressions
/// that could not be proven as to whether they mismatch with new-expression
/// used in initializer of the field.
typedef std::pair<SourceLocation, bool> DeleteExprLoc;
typedef llvm::SmallVector<DeleteExprLoc, 4> DeleteLocs;
llvm::MapVector<FieldDecl *, DeleteLocs> DeleteExprs;

typedef llvm::SmallPtrSet<const CXXRecordDecl*, 8> RecordDeclSetTy;

/// PureVirtualClassDiagSet - a set of class declarations which we have
/// emitted a list of pure virtual functions. Used to prevent emitting the
/// same list more than once.
std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;

/// ParsingInitForAutoVars - a set of declarations with auto types for which
/// we are currently parsing the initializer.
llvm::SmallPtrSet<const Decl*, 4> ParsingInitForAutoVars;

/// Look for a locally scoped extern "C" declaration by the given name.
NamedDecl *findLocallyScopedExternCDecl(DeclarationName Name);

typedef LazyVector<VarDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadTentativeDefinitions, 2, 2>
  TentativeDefinitionsType;

/// All the tentative definitions encountered in the TU.
TentativeDefinitionsType TentativeDefinitions;

typedef LazyVector<const DeclaratorDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadUnusedFileScopedDecls, 2, 2>
  UnusedFileScopedDeclsType;

/// The set of file scoped decls seen so far that have not been used
/// and must warn if not used. Only contains the first declaration.
UnusedFileScopedDeclsType UnusedFileScopedDecls;

typedef LazyVector<CXXConstructorDecl *, ExternalSemaSource,
                   &ExternalSemaSource::ReadDelegatingConstructors, 2, 2>
  DelegatingCtorDeclsType;

/// All the delegating constructors seen so far in the file, used for
/// cycle detection at the end of the TU.
DelegatingCtorDeclsType DelegatingCtorDecls;

/// All the overriding functions seen during a class definition
/// that had their exception spec checks delayed, plus the overridden
/// function.
SmallVector<std::pair<const CXXMethodDecl*, const CXXMethodDecl*>, 2>
  DelayedOverridingExceptionSpecChecks;

/// All the function redeclarations seen during a class definition that had
/// their exception spec checks delayed, plus the prior declaration they
/// should be checked against. Except during error recovery, the new decl
/// should always be a friend declaration, as that's the only valid way to
/// redeclare a special member before its class is complete.
SmallVector<std::pair<FunctionDecl*, FunctionDecl*>, 2>
  DelayedEquivalentExceptionSpecChecks;

typedef llvm::MapVector<const FunctionDecl *,
                        std::unique_ptr<LateParsedTemplate>>
    LateParsedTemplateMapT;
LateParsedTemplateMapT LateParsedTemplateMap;

/// Callback to the parser to parse templated functions when needed.
typedef void LateTemplateParserCB(void *P, LateParsedTemplate &LPT);
typedef void LateTemplateParserCleanupCB(void *P);
LateTemplateParserCB *LateTemplateParser;
LateTemplateParserCleanupCB *LateTemplateParserCleanup;
void *OpaqueParser;

void SetLateTemplateParser(LateTemplateParserCB *LTP,
                           LateTemplateParserCleanupCB *LTPCleanup,
                           void *P) {
  LateTemplateParser = LTP;
  LateTemplateParserCleanup = LTPCleanup;
  OpaqueParser = P;
}

class DelayedDiagnostics;

class DelayedDiagnosticsState {
  sema::DelayedDiagnosticPool *SavedPool;
  friend class Sema::DelayedDiagnostics;
};
typedef DelayedDiagnosticsState ParsingDeclState;
typedef DelayedDiagnosticsState ProcessingContextState;

/// A class which encapsulates the logic for delaying diagnostics
/// during parsing and other processing.
class DelayedDiagnostics {
  /// The current pool of diagnostics into which delayed
  /// diagnostics should go.
  sema::DelayedDiagnosticPool *CurPool;

public:
  DelayedDiagnostics() : CurPool(nullptr) {}

  /// Adds a delayed diagnostic.
  void add(const sema::DelayedDiagnostic &diag); // in DelayedDiagnostic.h

  /// Determines whether diagnostics should be delayed.
  bool shouldDelayDiagnostics() { return CurPool != nullptr; }

  /// Returns the current delayed-diagnostics pool.
  sema::DelayedDiagnosticPool *getCurrentPool() const {
    return CurPool;
  }

  /// Enter a new scope.  Access and deprecation diagnostics will be
  /// collected in this pool.
  DelayedDiagnosticsState push(sema::DelayedDiagnosticPool &pool) {
    DelayedDiagnosticsState state;
    state.SavedPool = CurPool;
    CurPool = &pool;
    return state;
  }

  /// Leave a delayed-diagnostic state that was previously pushed.
  /// Do not emit any of the diagnostics.  This is performed as part
  /// of the bookkeeping of popping a pool "properly".
  void popWithoutEmitting(DelayedDiagnosticsState state) {
    CurPool = state.SavedPool;
  }

  /// Enter a new scope where access and deprecation diagnostics are
  /// not delayed.
  DelayedDiagnosticsState pushUndelayed() {
    DelayedDiagnosticsState state;
    state.SavedPool = CurPool;
    CurPool = nullptr;
    return state;
  }

  /// Undo a previous pushUndelayed().
  void popUndelayed(DelayedDiagnosticsState state) {
    assert(CurPool == nullptr)((CurPool == nullptr) ? static_cast<void> (0) : __assert_fail
 ("CurPool == nullptr", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 769, __PRETTY_FUNCTION__));
    CurPool = state.SavedPool;
  }
} DelayedDiagnostics;

/// A RAII object to temporarily push a declaration context.
class ContextRAII {
private:
  Sema &S;
  DeclContext *SavedContext;
  ProcessingContextState SavedContextState;
  QualType SavedCXXThisTypeOverride;

public:
  ContextRAII(Sema &S, DeclContext *ContextToPush, bool NewThisContext = true)
    : S(S), SavedContext(S.CurContext),
      SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
      SavedCXXThisTypeOverride(S.CXXThisTypeOverride)
  {
    assert(ContextToPush && "pushing null context")((ContextToPush && "pushing null context") ? static_cast
<void> (0) : __assert_fail ("ContextToPush && \"pushing null context\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 788, __PRETTY_FUNCTION__));
    S.CurContext = ContextToPush;
    if (NewThisContext)
      S.CXXThisTypeOverride = QualType();
  }

  void pop() {
    if (!SavedContext) return;
    S.CurContext = SavedContext;
    S.DelayedDiagnostics.popUndelayed(SavedContextState);
    S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
    SavedContext = nullptr;
  }

  ~ContextRAII() {
    pop();
  }
};

/// Used to change context to isConstantEvaluated without pushing a heavy
/// ExpressionEvaluationContextRecord object.
bool isConstantEvaluatedOverride;

bool isConstantEvaluated() {
  return ExprEvalContexts.back().isConstantEvaluated() ||
         isConstantEvaluatedOverride;
}

/// RAII object to handle the state changes required to synthesize
/// a function body.
class SynthesizedFunctionScope {
  Sema &S;
  Sema::ContextRAII SavedContext;
  bool PushedCodeSynthesisContext = false;

public:
  SynthesizedFunctionScope(Sema &S, DeclContext *DC)
      : S(S), SavedContext(S, DC) {
    S.PushFunctionScope();
    S.PushExpressionEvaluationContext(
        Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
    if (auto *FD = dyn_cast<FunctionDecl>(DC))
      FD->setWillHaveBody(true);
    else
      assert(isa<ObjCMethodDecl>(DC))((isa<ObjCMethodDecl>(DC)) ? static_cast<void> (0
) : __assert_fail ("isa<ObjCMethodDecl>(DC)", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 832, __PRETTY_FUNCTION__));
  }

  void addContextNote(SourceLocation UseLoc) {
    assert(!PushedCodeSynthesisContext)((!PushedCodeSynthesisContext) ? static_cast<void> (0) :
 __assert_fail ("!PushedCodeSynthesisContext", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 836, __PRETTY_FUNCTION__));

    Sema::CodeSynthesisContext Ctx;
    Ctx.Kind = Sema::CodeSynthesisContext::DefiningSynthesizedFunction;
    Ctx.PointOfInstantiation = UseLoc;
    Ctx.Entity = cast<Decl>(S.CurContext);
    S.pushCodeSynthesisContext(Ctx);

    PushedCodeSynthesisContext = true;
  }

  ~SynthesizedFunctionScope() {
    if (PushedCodeSynthesisContext)
      S.popCodeSynthesisContext();
    if (auto *FD = dyn_cast<FunctionDecl>(S.CurContext))
      FD->setWillHaveBody(false);
    S.PopExpressionEvaluationContext();
    S.PopFunctionScopeInfo();
  }
};

/// WeakUndeclaredIdentifiers - Identifiers contained in
/// \#pragma weak before declared. rare. may alias another
/// identifier, declared or undeclared
llvm::MapVector<IdentifierInfo *, WeakInfo> WeakUndeclaredIdentifiers;

/// ExtnameUndeclaredIdentifiers - Identifiers contained in
/// \#pragma redefine_extname before declared.  Used in Solaris system headers
/// to define functions that occur in multiple standards to call the version
/// in the currently selected standard.
llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*> ExtnameUndeclaredIdentifiers;


/// Load weak undeclared identifiers from the external source.
void LoadExternalWeakUndeclaredIdentifiers();

/// WeakTopLevelDecl - Translation-unit scoped declarations generated by
/// \#pragma weak during processing of other Decls.
/// I couldn't figure out a clean way to generate these in-line, so
/// we store them here and handle separately -- which is a hack.
/// It would be best to refactor this.
SmallVector<Decl*,2> WeakTopLevelDecl;

IdentifierResolver IdResolver;

/// Translation Unit Scope - useful to Objective-C actions that need
/// to lookup file scope declarations in the "ordinary" C decl namespace.
/// For example, user-defined classes, built-in "id" type, etc.
Scope *TUScope;

/// The C++ "std" namespace, where the standard library resides.
LazyDeclPtr StdNamespace;

/// The C++ "std::bad_alloc" class, which is defined by the C++
/// standard library.
LazyDeclPtr StdBadAlloc;

/// The C++ "std::align_val_t" enum class, which is defined by the C++
/// standard library.
LazyDeclPtr StdAlignValT;

/// The C++ "std::experimental" namespace, where the experimental parts
/// of the standard library resides.
NamespaceDecl *StdExperimentalNamespaceCache;

/// The C++ "std::initializer_list" template, which is defined in
/// \<initializer_list>.
ClassTemplateDecl *StdInitializerList;

/// The C++ "std::coroutine_traits" template, which is defined in
/// \<coroutine_traits>
ClassTemplateDecl *StdCoroutineTraitsCache;

/// The C++ "type_info" declaration, which is defined in \<typeinfo>.
RecordDecl *CXXTypeInfoDecl;

/// The MSVC "_GUID" struct, which is defined in MSVC header files.
RecordDecl *MSVCGuidDecl;

/// Caches identifiers/selectors for NSFoundation APIs.
std::unique_ptr<NSAPI> NSAPIObj;

/// The declaration of the Objective-C NSNumber class.
ObjCInterfaceDecl *NSNumberDecl;

/// The declaration of the Objective-C NSValue class.
ObjCInterfaceDecl *NSValueDecl;

/// Pointer to NSNumber type (NSNumber *).
QualType NSNumberPointer;

/// Pointer to NSValue type (NSValue *).
QualType NSValuePointer;

/// The Objective-C NSNumber methods used to create NSNumber literals.
ObjCMethodDecl *NSNumberLiteralMethods[NSAPI::NumNSNumberLiteralMethods];

/// The declaration of the Objective-C NSString class.
ObjCInterfaceDecl *NSStringDecl;

/// Pointer to NSString type (NSString *).
QualType NSStringPointer;

/// The declaration of the stringWithUTF8String: method.
ObjCMethodDecl *StringWithUTF8StringMethod;

/// The declaration of the valueWithBytes:objCType: method.
ObjCMethodDecl *ValueWithBytesObjCTypeMethod;

/// The declaration of the Objective-C NSArray class.
ObjCInterfaceDecl *NSArrayDecl;

/// The declaration of the arrayWithObjects:count: method.
ObjCMethodDecl *ArrayWithObjectsMethod;

/// The declaration of the Objective-C NSDictionary class.
ObjCInterfaceDecl *NSDictionaryDecl;

/// The declaration of the dictionaryWithObjects:forKeys:count: method.
ObjCMethodDecl *DictionaryWithObjectsMethod;

/// id<NSCopying> type.
QualType QIDNSCopying;

/// will hold 'respondsToSelector:'
Selector RespondsToSelectorSel;

/// A flag to remember whether the implicit forms of operator new and delete
/// have been declared.
bool GlobalNewDeleteDeclared;

/// A flag to indicate that we're in a context that permits abstract
/// references to fields.  This is really a
bool AllowAbstractFieldReference;

/// Describes how the expressions currently being parsed are
/// evaluated at run-time, if at all.
enum class ExpressionEvaluationContext {
  /// The current expression and its subexpressions occur within an
  /// unevaluated operand (C++11 [expr]p7), such as the subexpression of
  /// \c sizeof, where the type of the expression may be significant but
  /// no code will be generated to evaluate the value of the expression at
  /// run time.
  Unevaluated,

  /// The current expression occurs within a braced-init-list within
  /// an unevaluated operand. This is mostly like a regular unevaluated
  /// context, except that we still instantiate constexpr functions that are
  /// referenced here so that we can perform narrowing checks correctly.
  UnevaluatedList,

  /// The current expression occurs within a discarded statement.
  /// This behaves largely similarly to an unevaluated operand in preventing
  /// definitions from being required, but not in other ways.
  DiscardedStatement,

  /// The current expression occurs within an unevaluated
  /// operand that unconditionally permits abstract references to
  /// fields, such as a SIZE operator in MS-style inline assembly.
  UnevaluatedAbstract,

  /// The current context is "potentially evaluated" in C++11 terms,
  /// but the expression is evaluated at compile-time (like the values of
  /// cases in a switch statement).
  ConstantEvaluated,

  /// The current expression is potentially evaluated at run time,
  /// which means that code may be generated to evaluate the value of the
  /// expression at run time.
  PotentiallyEvaluated,

  /// The current expression is potentially evaluated, but any
  /// declarations referenced inside that expression are only used if
  /// in fact the current expression is used.
  ///
  /// This value is used when parsing default function arguments, for which
  /// we would like to provide diagnostics (e.g., passing non-POD arguments
  /// through varargs) but do not want to mark declarations as "referenced"
  /// until the default argument is used.
  PotentiallyEvaluatedIfUsed
};

/// Data structure used to record current or nested
/// expression evaluation contexts.
struct ExpressionEvaluationContextRecord {
  /// The expression evaluation context.
  ExpressionEvaluationContext Context;

  /// Whether the enclosing context needed a cleanup.
  CleanupInfo ParentCleanup;

  /// Whether we are in a decltype expression.
  bool IsDecltype;

  /// The number of active cleanup objects when we entered
  /// this expression evaluation context.
  unsigned NumCleanupObjects;

  /// The number of typos encountered during this expression evaluation
  /// context (i.e. the number of TypoExprs created).
  unsigned NumTypos;

  MaybeODRUseExprSet SavedMaybeODRUseExprs;

  /// The lambdas that are present within this context, if it
  /// is indeed an unevaluated context.
  SmallVector<LambdaExpr *, 2> Lambdas;

  /// The declaration that provides context for lambda expressions
  /// and block literals if the normal declaration context does not
  /// suffice, e.g., in a default function argument.
  Decl *ManglingContextDecl;

  /// If we are processing a decltype type, a set of call expressions
  /// for which we have deferred checking the completeness of the return type.
  SmallVector<CallExpr *, 8> DelayedDecltypeCalls;

  /// If we are processing a decltype type, a set of temporary binding
  /// expressions for which we have deferred checking the destructor.
  SmallVector<CXXBindTemporaryExpr *, 8> DelayedDecltypeBinds;

  llvm::SmallPtrSet<const Expr *, 8> PossibleDerefs;

  /// Expressions appearing as the LHS of a volatile assignment in this
  /// context. We produce a warning for these when popping the context if
  /// they are not discarded-value expressions nor unevaluated operands.
  SmallVector<Expr*, 2> VolatileAssignmentLHSs;

  /// \brief Describes whether we are in an expression constext which we have
  /// to handle differently.
  enum ExpressionKind {
    EK_Decltype, EK_TemplateArgument, EK_Other
  } ExprContext;

  ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
                                    unsigned NumCleanupObjects,
                                    CleanupInfo ParentCleanup,
                                    Decl *ManglingContextDecl,
                                    ExpressionKind ExprContext)
      : Context(Context), ParentCleanup(ParentCleanup),
        NumCleanupObjects(NumCleanupObjects), NumTypos(0),
        ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext) {}

  bool isUnevaluated() const {
    return Context == ExpressionEvaluationContext::Unevaluated ||
           Context == ExpressionEvaluationContext::UnevaluatedAbstract ||
           Context == ExpressionEvaluationContext::UnevaluatedList;
  }
  bool isConstantEvaluated() const {
    return Context == ExpressionEvaluationContext::ConstantEvaluated;
  }
};

/// A stack of expression evaluation contexts.
SmallVector<ExpressionEvaluationContextRecord, 8> ExprEvalContexts;

/// Emit a warning for all pending noderef expressions that we recorded.
void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);

/// Compute the mangling number context for a lambda expression or
/// block literal. Also return the extra mangling decl if any.
///
/// \param DC - The DeclContext containing the lambda expression or
/// block literal.
std::tuple<MangleNumberingContext *, Decl *>
getCurrentMangleNumberContext(const DeclContext *DC);


/// SpecialMemberOverloadResult - The overloading result for a special member
/// function.
///
/// This is basically a wrapper around PointerIntPair. The lowest bits of the
/// integer are used to determine whether overload resolution succeeded.
class SpecialMemberOverloadResult {
public:
  enum Kind {
    NoMemberOrDeleted,
    Ambiguous,
    Success
  };

private:
  llvm::PointerIntPair<CXXMethodDecl*, 2> Pair;

public:
  SpecialMemberOverloadResult() : Pair() {}
  SpecialMemberOverloadResult(CXXMethodDecl *MD)
      : Pair(MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}

  CXXMethodDecl *getMethod() const { return Pair.getPointer(); }
  void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }

  Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
  void setKind(Kind K) { Pair.setInt(K); }
};

class SpecialMemberOverloadResultEntry
    : public llvm::FastFoldingSetNode,
      public SpecialMemberOverloadResult {
public:
  SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
    : FastFoldingSetNode(ID)
  {}
};

/// A cache of special member function overload resolution results
/// for C++ records.
llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;

/// A cache of the flags available in enumerations with the flag_bits
/// attribute.
mutable llvm::DenseMap<const EnumDecl*, llvm::APInt> FlagBitsCache;

/// The kind of translation unit we are processing.
///
/// When we're processing a complete translation unit, Sema will perform
/// end-of-translation-unit semantic tasks (such as creating
/// initializers for tentative definitions in C) once parsing has
/// completed. Modules and precompiled headers perform different kinds of
/// checks.
TranslationUnitKind TUKind;

llvm::BumpPtrAllocator BumpAlloc;

/// The number of SFINAE diagnostics that have been trapped.
unsigned NumSFINAEErrors;

typedef llvm::DenseMap<ParmVarDecl *, llvm::TinyPtrVector<ParmVarDecl *>>
  UnparsedDefaultArgInstantiationsMap;

/// A mapping from parameters with unparsed default arguments to the
/// set of instantiations of each parameter.
///
/// This mapping is a temporary data structure used when parsing
/// nested class templates or nested classes of class templates,
/// where we might end up instantiating an inner class before the
/// default arguments of its methods have been parsed.
UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;

// Contains the locations of the beginning of unparsed default
// argument locations.
llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;

/// UndefinedInternals - all the used, undefined objects which require a
/// definition in this translation unit.
llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;

/// Determine if VD, which must be a variable or function, is an external
/// symbol that nonetheless can't be referenced from outside this translation
/// unit because its type has no linkage and it's not extern "C".
bool isExternalWithNoLinkageType(ValueDecl *VD);

/// Obtain a sorted list of functions that are undefined but ODR-used.
void getUndefinedButUsed(
    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined);

/// Retrieves list of suspicious delete-expressions that will be checked at
/// the end of translation unit.
const llvm::MapVector<FieldDecl *, DeleteLocs> &
getMismatchingDeleteExpressions() const;

typedef std::pair<ObjCMethodList, ObjCMethodList> GlobalMethods;
typedef llvm::DenseMap<Selector, GlobalMethods> GlobalMethodPool;

/// Method Pool - allows efficient lookup when typechecking messages to "id".
/// We need to maintain a list, since selectors can have differing signatures
/// across classes. In Cocoa, this happens to be extremely uncommon (only 1%
/// of selectors are "overloaded").
/// At the head of the list it is recorded whether there were 0, 1, or >= 2
/// methods inside categories with a particular selector.
GlobalMethodPool MethodPool;

/// Method selectors used in a \@selector expression. Used for implementation
/// of -Wselector.
llvm::MapVector<Selector, SourceLocation> ReferencedSelectors;

/// List of SourceLocations where 'self' is implicitly retained inside a
/// block.
llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, 1>
    ImplicitlyRetainedSelfLocs;

/// Kinds of C++ special members.
enum CXXSpecialMember {
  CXXDefaultConstructor,
  CXXCopyConstructor,
  CXXMoveConstructor,
  CXXCopyAssignment,
  CXXMoveAssignment,
  CXXDestructor,
  CXXInvalid
};

typedef llvm::PointerIntPair<CXXRecordDecl *, 3, CXXSpecialMember>
    SpecialMemberDecl;

/// The C++ special members which we are currently in the process of
/// declaring. If this process recursively triggers the declaration of the
/// same special member, we should act as if it is not yet declared.
llvm::SmallPtrSet<SpecialMemberDecl, 4> SpecialMembersBeingDeclared;

/// The function definitions which were renamed as part of typo-correction
/// to match their respective declarations. We want to keep track of them
/// to ensure that we don't emit a "redefinition" error if we encounter a
/// correctly named definition after the renamed definition.
llvm::SmallPtrSet<const NamedDecl *, 4> TypoCorrectedFunctionDefinitions;

/// Stack of types that correspond to the parameter entities that are
/// currently being copy-initialized. Can be empty.
llvm::SmallVector<QualType, 4> CurrentParameterCopyTypes;

void ReadMethodPool(Selector Sel);
void updateOutOfDateSelector(Selector Sel);

/// Private Helper predicate to check for 'self'.
bool isSelfExpr(Expr *RExpr);
bool isSelfExpr(Expr *RExpr, const ObjCMethodDecl *Method);

/// Cause the active diagnostic on the DiagosticsEngine to be
/// emitted. This is closely coupled to the SemaDiagnosticBuilder class and
/// should not be used elsewhere.
void EmitCurrentDiagnostic(unsigned DiagID);

/// Records and restores the FP_CONTRACT state on entry/exit of compound
/// statements.
class FPContractStateRAII {
public:
  FPContractStateRAII(Sema &S) : S(S), OldFPFeaturesState(S.FPFeatures) {}
  ~FPContractStateRAII() { S.FPFeatures = OldFPFeaturesState; }

private:
  Sema& S;
  FPOptions OldFPFeaturesState;
};

void addImplicitTypedef(StringRef Name, QualType T);

bool WarnedStackExhausted = false;

1274public:
Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     TranslationUnitKind TUKind = TU_Complete,
     CodeCompleteConsumer *CompletionConsumer = nullptr);
~Sema();

/// Perform initialization that occurs after the parser has been
/// initialized but before it parses anything.
void Initialize();

const LangOptions &getLangOpts() const { return LangOpts; }
OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
FPOptions     &getFPOptions() { return FPFeatures; }

DiagnosticsEngine &getDiagnostics() const { return Diags; }
SourceManager &getSourceManager() const { return SourceMgr; }
Preprocessor &getPreprocessor() const { return PP; }
ASTContext &getASTContext() const { return Context; }
ASTConsumer &getASTConsumer() const { return Consumer; }
ASTMutationListener *getASTMutationListener() const;
ExternalSemaSource* getExternalSource() const { return ExternalSource; }

///Registers an external source. If an external source already exists,
/// creates a multiplex external source and appends to it.
///
///\param[in] E - A non-null external sema source.
///
void addExternalSource(ExternalSemaSource *E);

void PrintStats() const;

/// Warn that the stack is nearly exhausted.
void warnStackExhausted(SourceLocation Loc);

/// Run some code with "sufficient" stack space. (Currently, at least 256K is
/// guaranteed). Produces a warning if we're low on stack space and allocates
/// more in that case. Use this in code that may recurse deeply (for example,
/// in template instantiation) to avoid stack overflow.
void runWithSufficientStackSpace(SourceLocation Loc,
                                 llvm::function_ref<void()> Fn);

/// Helper class that creates diagnostics with optional
/// template instantiation stacks.
///
/// This class provides a wrapper around the basic DiagnosticBuilder
/// class that emits diagnostics. SemaDiagnosticBuilder is
/// responsible for emitting the diagnostic (as DiagnosticBuilder
/// does) and, if the diagnostic comes from inside a template
/// instantiation, printing the template instantiation stack as
/// well.
class SemaDiagnosticBuilder : public DiagnosticBuilder {
  Sema &SemaRef;
  unsigned DiagID;

public:
  SemaDiagnosticBuilder(DiagnosticBuilder &DB, Sema &SemaRef, unsigned DiagID)
    : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) { }

  // This is a cunning lie. DiagnosticBuilder actually performs move
  // construction in its copy constructor (but due to varied uses, it's not
  // possible to conveniently express this as actual move construction). So
  // the default copy ctor here is fine, because the base class disables the
  // source anyway, so the user-defined ~SemaDiagnosticBuilder is a safe no-op
  // in that case anwyay.
  SemaDiagnosticBuilder(const SemaDiagnosticBuilder&) = default;

  ~SemaDiagnosticBuilder() {
    // If we aren't active, there is nothing to do.
    if (!isActive()) return;

    // Otherwise, we need to emit the diagnostic. First flush the underlying
    // DiagnosticBuilder data, and clear the diagnostic builder itself so it
    // won't emit the diagnostic in its own destructor.
    //
    // This seems wasteful, in that as written the DiagnosticBuilder dtor will
    // do its own needless checks to see if the diagnostic needs to be
    // emitted. However, because we take care to ensure that the builder
    // objects never escape, a sufficiently smart compiler will be able to
    // eliminate that code.
    FlushCounts();
    Clear();

    // Dispatch to Sema to emit the diagnostic.
    SemaRef.EmitCurrentDiagnostic(DiagID);
  }

  /// Teach operator<< to produce an object of the correct type.
  template<typename T>
  friend const SemaDiagnosticBuilder &operator<<(
      const SemaDiagnosticBuilder &Diag, const T &Value) {
    const DiagnosticBuilder &BaseDiag = Diag;
    BaseDiag << Value;
    return Diag;
  }
};

/// Emit a diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID) {
  DiagnosticBuilder DB = Diags.Report(Loc, DiagID);
  return SemaDiagnosticBuilder(DB, *this, DiagID);
}

/// Emit a partial diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, const PartialDiagnostic& PD);

/// Build a partial diagnostic.
PartialDiagnostic PDiag(unsigned DiagID = 0); // in SemaInternal.h

bool findMacroSpelling(SourceLocation &loc, StringRef name);

/// Get a string to suggest for zero-initialization of a type.
std::string
getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const;
std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;

/// Calls \c Lexer::getLocForEndOfToken()
SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = 0);

/// Retrieve the module loader associated with the preprocessor.
ModuleLoader &getModuleLoader() const;

void emitAndClearUnusedLocalTypedefWarnings();

enum TUFragmentKind {
  /// The global module fragment, between 'module;' and a module-declaration.
  Global,
  /// A normal translation unit fragment. For a non-module unit, this is the
  /// entire translation unit. Otherwise, it runs from the module-declaration
  /// to the private-module-fragment (if any) or the end of the TU (if not).
  Normal,
  /// The private module fragment, between 'module :private;' and the end of
  /// the translation unit.
  Private
};

void ActOnStartOfTranslationUnit();
void ActOnEndOfTranslationUnit();
void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);

void CheckDelegatingCtorCycles();

Scope *getScopeForContext(DeclContext *Ctx);

void PushFunctionScope();
void PushBlockScope(Scope *BlockScope, BlockDecl *Block);
sema::LambdaScopeInfo *PushLambdaScope();

/// This is used to inform Sema what the current TemplateParameterDepth
/// is during Parsing.  Currently it is used to pass on the depth
/// when parsing generic lambda 'auto' parameters.
void RecordParsingTemplateParameterDepth(unsigned Depth);

void PushCapturedRegionScope(Scope *RegionScope, CapturedDecl *CD,
                             RecordDecl *RD, CapturedRegionKind K,
                             unsigned OpenMPCaptureLevel = 0);

/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
/// time after they've been popped.
class PoppedFunctionScopeDeleter {
  Sema *Self;

public:
  explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
  void operator()(sema::FunctionScopeInfo *Scope) const;
};

using PoppedFunctionScopePtr =
    std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;

PoppedFunctionScopePtr
PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy *WP = nullptr,
                     const Decl *D = nullptr,
                     QualType BlockType = QualType());

sema::FunctionScopeInfo *getCurFunction() const {
  return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
}

sema::FunctionScopeInfo *getEnclosingFunction() const;

void setFunctionHasBranchIntoScope();
void setFunctionHasBranchProtectedScope();
void setFunctionHasIndirectGoto();

void PushCompoundScope(bool IsStmtExpr);
void PopCompoundScope();

sema::CompoundScopeInfo &getCurCompoundScope() const;

bool hasAnyUnrecoverableErrorsInThisFunction() const;

/// Retrieve the current block, if any.
sema::BlockScopeInfo *getCurBlock();

/// Get the innermost lambda enclosing the current location, if any. This
/// looks through intervening non-lambda scopes such as local functions and
/// blocks.
sema::LambdaScopeInfo *getEnclosingLambda() const;

/// Retrieve the current lambda scope info, if any.
/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
/// lambda scope info ignoring all inner capturing scopes that are not
/// lambda scopes.
sema::LambdaScopeInfo *
getCurLambda(bool IgnoreNonLambdaCapturingScope = false);

/// Retrieve the current generic lambda info, if any.
sema::LambdaScopeInfo *getCurGenericLambda();

/// Retrieve the current captured region, if any.
sema::CapturedRegionScopeInfo *getCurCapturedRegion();

/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
SmallVectorImpl<Decl *> &WeakTopLevelDecls() { return WeakTopLevelDecl; }

void ActOnComment(SourceRange Comment);

//===--------------------------------------------------------------------===//
// Type Analysis / Processing: SemaType.cpp.
//

QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
                            const DeclSpec *DS = nullptr);
QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
                            const DeclSpec *DS = nullptr);
QualType BuildPointerType(QualType T,
                          SourceLocation Loc, DeclarationName Entity);
QualType BuildReferenceType(QualType T, bool LValueRef,
                            SourceLocation Loc, DeclarationName Entity);
QualType BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
                        Expr *ArraySize, unsigned Quals,
                        SourceRange Brackets, DeclarationName Entity);
QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
QualType BuildExtVectorType(QualType T, Expr *ArraySize,
                            SourceLocation AttrLoc);
QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
                               SourceLocation AttrLoc);

/// Same as above, but constructs the AddressSpace index if not provided.
QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
                               SourceLocation AttrLoc);

bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);

bool CheckFunctionReturnType(QualType T, SourceLocation Loc);

/// Build a function type.
///
/// This routine checks the function type according to C++ rules and
/// under the assumption that the result type and parameter types have
/// just been instantiated from a template. It therefore duplicates
/// some of the behavior of GetTypeForDeclarator, but in a much
/// simpler form that is only suitable for this narrow use case.
///
/// \param T The return type of the function.
///
/// \param ParamTypes The parameter types of the function. This array
/// will be modified to account for adjustments to the types of the
/// function parameters.
///
/// \param Loc The location of the entity whose type involves this
/// function type or, if there is no such entity, the location of the
/// type that will have function type.
///
/// \param Entity The name of the entity that involves the function
/// type, if known.
///
/// \param EPI Extra information about the function type. Usually this will
/// be taken from an existing function with the same prototype.
///
/// \returns A suitable function type, if there are no errors. The
/// unqualified type will always be a FunctionProtoType.
/// Otherwise, returns a NULL type.
QualType BuildFunctionType(QualType T,
                           MutableArrayRef<QualType> ParamTypes,
                           SourceLocation Loc, DeclarationName Entity,
                           const FunctionProtoType::ExtProtoInfo &EPI);

QualType BuildMemberPointerType(QualType T, QualType Class,
                                SourceLocation Loc,
                                DeclarationName Entity);
QualType BuildBlockPointerType(QualType T,
                               SourceLocation Loc, DeclarationName Entity);
QualType BuildParenType(QualType T);
QualType BuildAtomicType(QualType T, SourceLocation Loc);
QualType BuildReadPipeType(QualType T,
                       SourceLocation Loc);
QualType BuildWritePipeType(QualType T,
                       SourceLocation Loc);

TypeSourceInfo *GetTypeForDeclarator(Declarator &D, Scope *S);
TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);

/// Package the given type and TSI into a ParsedType.
ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
DeclarationNameInfo GetNameForDeclarator(Declarator &D);
DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
static QualType GetTypeFromParser(ParsedType Ty,
                                  TypeSourceInfo **TInfo = nullptr);
CanThrowResult canThrow(const Expr *E);
const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
                                              const FunctionProtoType *FPT);
void UpdateExceptionSpec(FunctionDecl *FD,
                         const FunctionProtoType::ExceptionSpecInfo &ESI);
bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
bool CheckDistantExceptionSpec(QualType T);
bool CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New);
bool CheckEquivalentExceptionSpec(
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool CheckEquivalentExceptionSpec(
    const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
bool CheckExceptionSpecSubset(const PartialDiagnostic &DiagID,
                              const PartialDiagnostic &NestedDiagID,
                              const PartialDiagnostic &NoteID,
                              const PartialDiagnostic &NoThrowDiagID,
                              const FunctionProtoType *Superset,
                              SourceLocation SuperLoc,
                              const FunctionProtoType *Subset,
                              SourceLocation SubLoc);
bool CheckParamExceptionSpec(const PartialDiagnostic &NestedDiagID,
                             const PartialDiagnostic &NoteID,
                             const FunctionProtoType *Target,
                             SourceLocation TargetLoc,
                             const FunctionProtoType *Source,
                             SourceLocation SourceLoc);

TypeResult ActOnTypeName(Scope *S, Declarator &D);

/// The parser has parsed the context-sensitive type 'instancetype'
/// in an Objective-C message declaration. Return the appropriate type.
ParsedType ActOnObjCInstanceType(SourceLocation Loc);

/// Abstract class used to diagnose incomplete types.
struct TypeDiagnoser {
  TypeDiagnoser() {}

  virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = 0;
  virtual ~TypeDiagnoser() {}
};

static int getPrintable(int I) { return I; }
static unsigned getPrintable(unsigned I) { return I; }
static bool getPrintable(bool B) { return B; }
static const char * getPrintable(const char *S) { return S; }
static StringRef getPrintable(StringRef S) { return S; }
static const std::string &getPrintable(const std::string &S) { return S; }
static const IdentifierInfo *getPrintable(const IdentifierInfo *II) {
  return II;
}
static DeclarationName getPrintable(DeclarationName N) { return N; }
static QualType getPrintable(QualType T) { return T; }
static SourceRange getPrintable(SourceRange R) { return R; }
static SourceRange getPrintable(SourceLocation L) { return L; }
static SourceRange getPrintable(const Expr *E) { return E->getSourceRange(); }
static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange();}

template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
  unsigned DiagID;
  std::tuple<const Ts &...> Args;

  template <std::size_t... Is>
  void emit(const SemaDiagnosticBuilder &DB,
            std::index_sequence<Is...>) const {
    // Apply all tuple elements to the builder in order.
    bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
    (void)Dummy;
  }

public:
  BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
      : TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
    assert(DiagID != 0 && "no diagnostic for type diagnoser")((DiagID != 0 && "no diagnostic for type diagnoser") ?
 static_cast<void> (0) : __assert_fail ("DiagID != 0 && \"no diagnostic for type diagnoser\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 1649, __PRETTY_FUNCTION__));
  }

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
    emit(DB, std::index_sequence_for<Ts...>());
    DB << T;
  }
};

1659private:
/// Methods for marking which expressions involve dereferencing a pointer
/// marked with the 'noderef' attribute. Expressions are checked bottom up as
/// they are parsed, meaning that a noderef pointer may not be accessed. For
/// example, in `&*p` where `p` is a noderef pointer, we will first parse the
/// `*p`, but need to check that `address of` is called on it. This requires
/// keeping a container of all pending expressions and checking if the address
/// of them are eventually taken.
void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
void CheckAddressOfNoDeref(const Expr *E);
void CheckMemberAccessOfNoDeref(const MemberExpr *E);

bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
                             TypeDiagnoser *Diagnoser);

struct ModuleScope {
  SourceLocation BeginLoc;
  clang::Module *Module = nullptr;
  bool ModuleInterface = false;
  bool ImplicitGlobalModuleFragment = false;
  VisibleModuleSet OuterVisibleModules;
};
/// The modules we're currently parsing.
llvm::SmallVector<ModuleScope, 16> ModuleScopes;

/// Namespace definitions that we will export when they finish.
llvm::SmallPtrSet<const NamespaceDecl*, 8> DeferredExportedNamespaces;

/// Get the module whose scope we are currently within.
Module *getCurrentModule() const {
  return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
}

VisibleModuleSet VisibleModules;

1694public:
/// Get the module owning an entity.
Module *getOwningModule(Decl *Entity) { return Entity->getOwningModule(); }

/// Make a merged definition of an existing hidden definition \p ND
/// visible at the specified location.
void makeMergedDefinitionVisible(NamedDecl *ND);

bool isModuleVisible(const Module *M, bool ModulePrivate = false);

/// Determine whether a declaration is visible to name lookup.
bool isVisible(const NamedDecl *D) {
  return !D->isHidden() || isVisibleSlow(D);
}

/// Determine whether any declaration of an entity is visible.
bool
hasVisibleDeclaration(const NamedDecl *D,
                      llvm::SmallVectorImpl<Module *> *Modules = nullptr) {
  return isVisible(D) || hasVisibleDeclarationSlow(D, Modules);
}
bool hasVisibleDeclarationSlow(const NamedDecl *D,
                               llvm::SmallVectorImpl<Module *> *Modules);

bool hasVisibleMergedDefinition(NamedDecl *Def);
bool hasMergedDefinitionInCurrentModule(NamedDecl *Def);

/// Determine if \p D and \p Suggested have a structurally compatible
/// layout as described in C11 6.2.7/1.
bool hasStructuralCompatLayout(Decl *D, Decl *Suggested);

/// Determine if \p D has a visible definition. If not, suggest a declaration
/// that should be made visible to expose the definition.
bool hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested,
                          bool OnlyNeedComplete = false);
bool hasVisibleDefinition(const NamedDecl *D) {
  NamedDecl *Hidden;
  return hasVisibleDefinition(const_cast<NamedDecl*>(D), &Hidden);
}

/// Determine if the template parameter \p D has a visible default argument.
bool
hasVisibleDefaultArgument(const NamedDecl *D,
                          llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if there is a visible declaration of \p D that is an explicit
/// specialization declaration for a specialization of a template. (For a
/// member specialization, use hasVisibleMemberSpecialization.)
bool hasVisibleExplicitSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if there is a visible declaration of \p D that is a member
/// specialization declaration (as opposed to an instantiated declaration).
bool hasVisibleMemberSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if \p A and \p B are equivalent internal linkage declarations
/// from different modules, and thus an ambiguity error can be downgraded to
/// an extension warning.
bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
                                            const NamedDecl *B);
void diagnoseEquivalentInternalLinkageDeclarations(
    SourceLocation Loc, const NamedDecl *D,
    ArrayRef<const NamedDecl *> Equiv);

bool isUsualDeallocationFunction(const CXXMethodDecl *FD);

bool isCompleteType(SourceLocation Loc, QualType T) {
  return !RequireCompleteTypeImpl(Loc, T, nullptr);
}
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         TypeDiagnoser &Diagnoser);
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         unsigned DiagID);

template <typename... Ts>
bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
                         const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteType(Loc, T, Diagnoser);
}

void completeExprArrayBound(Expr *E);
bool RequireCompleteExprType(Expr *E, TypeDiagnoser &Diagnoser);
bool RequireCompleteExprType(Expr *E, unsigned DiagID);

template <typename... Ts>
bool RequireCompleteExprType(Expr *E, unsigned DiagID, const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteExprType(E, Diagnoser);
}

bool RequireLiteralType(SourceLocation Loc, QualType T,
                        TypeDiagnoser &Diagnoser);
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);

template <typename... Ts>
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
                        const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireLiteralType(Loc, T, Diagnoser);
}

QualType getElaboratedType(ElaboratedTypeKeyword Keyword,
                           const CXXScopeSpec &SS, QualType T,
                           TagDecl *OwnedTagDecl = nullptr);

QualType BuildTypeofExprType(Expr *E, SourceLocation Loc);
/// If AsUnevaluated is false, E is treated as though it were an evaluated
/// context, such as when building a type for decltype(auto).
QualType BuildDecltypeType(Expr *E, SourceLocation Loc,
                           bool AsUnevaluated = true);
QualType BuildUnaryTransformType(QualType BaseType,
                                 UnaryTransformType::UTTKind UKind,
                                 SourceLocation Loc);

//===--------------------------------------------------------------------===//
// Symbol table / Decl tracking callbacks: SemaDecl.cpp.
//

struct SkipBodyInfo {
  SkipBodyInfo()
      : ShouldSkip(false), CheckSameAsPrevious(false), Previous(nullptr),
        New(nullptr) {}
  bool ShouldSkip;
  bool CheckSameAsPrevious;
  NamedDecl *Previous;
  NamedDecl *New;
};

DeclGroupPtrTy ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType = nullptr);

void DiagnoseUseOfUnimplementedSelectors();

bool isSimpleTypeSpecifier(tok::TokenKind Kind) const;

ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
                       Scope *S, CXXScopeSpec *SS = nullptr,
                       bool isClassName = false, bool HasTrailingDot = false,
                       ParsedType ObjectType = nullptr,
                       bool IsCtorOrDtorName = false,
                       bool WantNontrivialTypeSourceInfo = false,
                       bool IsClassTemplateDeductionContext = true,
                       IdentifierInfo **CorrectedII = nullptr);
TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
bool isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S);
void DiagnoseUnknownTypeName(IdentifierInfo *&II,
                             SourceLocation IILoc,
                             Scope *S,
                             CXXScopeSpec *SS,
                             ParsedType &SuggestedType,
                             bool IsTemplateName = false);

/// Attempt to behave like MSVC in situations where lookup of an unqualified
/// type name has failed in a dependent context. In these situations, we
/// automatically form a DependentTypeName that will retry lookup in a related
/// scope during instantiation.
ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
                                    SourceLocation NameLoc,
                                    bool IsTemplateTypeArg);

/// Describes the result of the name lookup and resolution performed
/// by \c ClassifyName().
enum NameClassificationKind {
  /// This name is not a type or template in this context, but might be
  /// something else.
  NC_Unknown,
  /// Classification failed; an error has been produced.
  NC_Error,
  /// The name has been typo-corrected to a keyword.
  NC_Keyword,
  /// The name was classified as a type.
  NC_Type,
  /// The name was classified as a specific non-type, non-template
  /// declaration. ActOnNameClassifiedAsNonType should be called to
  /// convert the declaration to an expression.
  NC_NonType,
  /// The name was classified as an ADL-only function name.
  /// ActOnNameClassifiedAsUndeclaredNonType should be called to convert the
  /// result to an expression.
  NC_UndeclaredNonType,
  /// The name denotes a member of a dependent type that could not be
  /// resolved. ActOnNameClassifiedAsDependentNonType should be called to
  /// convert the result to an expression.
  NC_DependentNonType,
  /// The name was classified as a non-type, and an expression representing
  /// that name has been formed.
  NC_ContextIndependentExpr,
  /// The name was classified as a template whose specializations are types.
  NC_TypeTemplate,
  /// The name was classified as a variable template name.
  NC_VarTemplate,
  /// The name was classified as a function template name.
  NC_FunctionTemplate,
  /// The name was classified as an ADL-only function template name.
  NC_UndeclaredTemplate,
};

class NameClassification {
  NameClassificationKind Kind;
  union {
    ExprResult Expr;
    NamedDecl *NonTypeDecl;
    TemplateName Template;
    ParsedType Type;
  };

  explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}

public:
  NameClassification(ParsedType Type) : Kind(NC_Type), Type(Type) {}

  NameClassification(const IdentifierInfo *Keyword) : Kind(NC_Keyword) {}

  static NameClassification Error() {
    return NameClassification(NC_Error);
  }

  static NameClassification Unknown() {
    return NameClassification(NC_Unknown);
  }

  static NameClassification ContextIndependentExpr(ExprResult E) {
    NameClassification Result(NC_ContextIndependentExpr);
    Result.Expr = E;
    return Result;
  }

  static NameClassification NonType(NamedDecl *D) {
    NameClassification Result(NC_NonType);
    Result.NonTypeDecl = D;
    return Result;
  }

  static NameClassification UndeclaredNonType() {
    return NameClassification(NC_UndeclaredNonType);
  }

  static NameClassification DependentNonType() {
    return NameClassification(NC_DependentNonType);
  }

  static NameClassification TypeTemplate(TemplateName Name) {
    NameClassification Result(NC_TypeTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification VarTemplate(TemplateName Name) {
    NameClassification Result(NC_VarTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification FunctionTemplate(TemplateName Name) {
    NameClassification Result(NC_FunctionTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification UndeclaredTemplate(TemplateName Name) {
    NameClassification Result(NC_UndeclaredTemplate);
    Result.Template = Name;
    return Result;
  }

  NameClassificationKind getKind() const { return Kind; }

  ExprResult getExpression() const {
    assert(Kind == NC_ContextIndependentExpr)((Kind == NC_ContextIndependentExpr) ? static_cast<void>
 (0) : __assert_fail ("Kind == NC_ContextIndependentExpr", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 1963, __PRETTY_FUNCTION__));
    return Expr;
  }

  ParsedType getType() const {
    assert(Kind == NC_Type)((Kind == NC_Type) ? static_cast<void> (0) : __assert_fail
 ("Kind == NC_Type", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 1968, __PRETTY_FUNCTION__));
    return Type;
  }

  NamedDecl *getNonTypeDecl() const {
    assert(Kind == NC_NonType)((Kind == NC_NonType) ? static_cast<void> (0) : __assert_fail
 ("Kind == NC_NonType", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 1973, __PRETTY_FUNCTION__));
    return NonTypeDecl;
  }

  TemplateName getTemplateName() const {
    assert(Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate ||((Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate || Kind
 == NC_VarTemplate || Kind == NC_UndeclaredTemplate) ? static_cast
<void> (0) : __assert_fail ("Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_UndeclaredTemplate"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 1979, __PRETTY_FUNCTION__))
           Kind == NC_VarTemplate || Kind == NC_UndeclaredTemplate)((Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate || Kind
 == NC_VarTemplate || Kind == NC_UndeclaredTemplate) ? static_cast
<void> (0) : __assert_fail ("Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_UndeclaredTemplate"
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 1979, __PRETTY_FUNCTION__));
    return Template;
  }

  TemplateNameKind getTemplateNameKind() const {
    switch (Kind) {
    case NC_TypeTemplate:
      return TNK_Type_template;
    case NC_FunctionTemplate:
      return TNK_Function_template;
    case NC_VarTemplate:
      return TNK_Var_template;
    case NC_UndeclaredTemplate:
      return TNK_Undeclared_template;
    default:
      llvm_unreachable("unsupported name classification.")::llvm::llvm_unreachable_internal("unsupported name classification."
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 1994);
    }
  }
};

/// Perform name lookup on the given name, classifying it based on
/// the results of name lookup and the following token.
///
/// This routine is used by the parser to resolve identifiers and help direct
/// parsing. When the identifier cannot be found, this routine will attempt
/// to correct the typo and classify based on the resulting name.
///
/// \param S The scope in which we're performing name lookup.
///
/// \param SS The nested-name-specifier that precedes the name.
///
/// \param Name The identifier. If typo correction finds an alternative name,
/// this pointer parameter will be updated accordingly.
///
/// \param NameLoc The location of the identifier.
///
/// \param NextToken The token following the identifier. Used to help
/// disambiguate the name.
///
/// \param CCC The correction callback, if typo correction is desired.
NameClassification ClassifyName(Scope *S, CXXScopeSpec &SS,
                                IdentifierInfo *&Name, SourceLocation NameLoc,
                                const Token &NextToken,
                                CorrectionCandidateCallback *CCC = nullptr);

/// Act on the result of classifying a name as an undeclared (ADL-only)
/// non-type declaration.
ExprResult ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
                                                  SourceLocation NameLoc);
/// Act on the result of classifying a name as an undeclared member of a
/// dependent base class.
ExprResult ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
                                                 IdentifierInfo *Name,
                                                 SourceLocation NameLoc,
                                                 bool IsAddressOfOperand);
/// Act on the result of classifying a name as a specific non-type
/// declaration.
ExprResult ActOnNameClassifiedAsNonType(Scope *S, const CXXScopeSpec &SS,
                                        NamedDecl *Found,
                                        SourceLocation NameLoc,
                                        const Token &NextToken);

/// Describes the detailed kind of a template name. Used in diagnostics.
enum class TemplateNameKindForDiagnostics {
  ClassTemplate,
  FunctionTemplate,
  VarTemplate,
  AliasTemplate,
  TemplateTemplateParam,
  Concept,
  DependentTemplate
};
TemplateNameKindForDiagnostics
getTemplateNameKindForDiagnostics(TemplateName Name);

/// Determine whether it's plausible that E was intended to be a
/// template-name.
bool mightBeIntendedToBeTemplateName(ExprResult E, bool &Dependent) {
  if (!getLangOpts().CPlusPlus || E.isInvalid())
    return false;
  Dependent = false;
  if (auto *DRE = dyn_cast<DeclRefExpr>(E.get()))
    return !DRE->hasExplicitTemplateArgs();
  if (auto *ME = dyn_cast<MemberExpr>(E.get()))
    return !ME->hasExplicitTemplateArgs();
  Dependent = true;
  if (auto *DSDRE = dyn_cast<DependentScopeDeclRefExpr>(E.get()))
    return !DSDRE->hasExplicitTemplateArgs();
  if (auto *DSME = dyn_cast<CXXDependentScopeMemberExpr>(E.get()))
    return !DSME->hasExplicitTemplateArgs();
  // Any additional cases recognized here should also be handled by
  // diagnoseExprIntendedAsTemplateName.
  return false;
}
void diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
                                        SourceLocation Less,
                                        SourceLocation Greater);

Decl *ActOnDeclarator(Scope *S, Declarator &D);

NamedDecl *HandleDeclarator(Scope *S, Declarator &D,
                            MultiTemplateParamsArg TemplateParameterLists);
void RegisterLocallyScopedExternCDecl(NamedDecl *ND, Scope *S);
bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
                                  DeclarationName Name, SourceLocation Loc,
                                  bool IsTemplateId);
void
diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                          SourceLocation FallbackLoc,
                          SourceLocation ConstQualLoc = SourceLocation(),
                          SourceLocation VolatileQualLoc = SourceLocation(),
                          SourceLocation RestrictQualLoc = SourceLocation(),
                          SourceLocation AtomicQualLoc = SourceLocation(),
                          SourceLocation UnalignedQualLoc = SourceLocation());

static bool adjustContextForLocalExternDecl(DeclContext *&DC);
void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
NamedDecl *getShadowedDeclaration(const TypedefNameDecl *D,
                                  const LookupResult &R);
NamedDecl *getShadowedDeclaration(const VarDecl *D, const LookupResult &R);
void CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
                 const LookupResult &R);
void CheckShadow(Scope *S, VarDecl *D);

/// Warn if 'E', which is an expression that is about to be modified, refers
/// to a shadowing declaration.
void CheckShadowingDeclModification(Expr *E, SourceLocation Loc);

void DiagnoseShadowingLambdaDecls(const sema::LambdaScopeInfo *LSI);

2110private:
/// Map of current shadowing declarations to shadowed declarations. Warn if
/// it looks like the user is trying to modify the shadowing declaration.
llvm::DenseMap<const NamedDecl *, const NamedDecl *> ShadowingDecls;

2115public:
void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
void handleTagNumbering(const TagDecl *Tag, Scope *TagScope);
void setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
                                  TypedefNameDecl *NewTD);
void CheckTypedefForVariablyModifiedType(Scope *S, TypedefNameDecl *D);
NamedDecl* ActOnTypedefDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                  TypeSourceInfo *TInfo,
                                  LookupResult &Previous);
NamedDecl* ActOnTypedefNameDecl(Scope* S, DeclContext* DC, TypedefNameDecl *D,
                                LookupResult &Previous, bool &Redeclaration);
NamedDecl *ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
                                   TypeSourceInfo *TInfo,
                                   LookupResult &Previous,
                                   MultiTemplateParamsArg TemplateParamLists,
                                   bool &AddToScope,
                                   ArrayRef<BindingDecl *> Bindings = None);
NamedDecl *
ActOnDecompositionDeclarator(Scope *S, Declarator &D,
                             MultiTemplateParamsArg TemplateParamLists);
// Returns true if the variable declaration is a redeclaration
bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
void CheckVariableDeclarationType(VarDecl *NewVD);
bool DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
                                   Expr *Init);
void CheckCompleteVariableDeclaration(VarDecl *VD);
void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);

NamedDecl* ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                   TypeSourceInfo *TInfo,
                                   LookupResult &Previous,
                                   MultiTemplateParamsArg TemplateParamLists,
                                   bool &AddToScope);
bool AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD);

enum class CheckConstexprKind {
  /// Diagnose issues that are non-constant or that are extensions.
  Diagnose,
  /// Identify whether this function satisfies the formal rules for constexpr
  /// functions in the current lanugage mode (with no extensions).
  CheckValid
};

bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
                                      CheckConstexprKind Kind);

void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
void FindHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
void NoteHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
// Returns true if the function declaration is a redeclaration
bool CheckFunctionDeclaration(Scope *S,
                              FunctionDecl *NewFD, LookupResult &Previous,
                              bool IsMemberSpecialization);
bool shouldLinkDependentDeclWithPrevious(Decl *D, Decl *OldDecl);
bool canFullyTypeCheckRedeclaration(ValueDecl *NewD, ValueDecl *OldD,
                                    QualType NewT, QualType OldT);
void CheckMain(FunctionDecl *FD, const DeclSpec &D);
void CheckMSVCRTEntryPoint(FunctionDecl *FD);
Attr *getImplicitCodeSegOrSectionAttrForFunction(const FunctionDecl *FD,
                                                 bool IsDefinition);
void CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D);
Decl *ActOnParamDeclarator(Scope *S, Declarator &D);
ParmVarDecl *BuildParmVarDeclForTypedef(DeclContext *DC,
                                        SourceLocation Loc,
                                        QualType T);
ParmVarDecl *CheckParameter(DeclContext *DC, SourceLocation StartLoc,
                            SourceLocation NameLoc, IdentifierInfo *Name,
                            QualType T, TypeSourceInfo *TSInfo,
                            StorageClass SC);
void ActOnParamDefaultArgument(Decl *param,
                               SourceLocation EqualLoc,
                               Expr *defarg);
void ActOnParamUnparsedDefaultArgument(Decl *param,
                                       SourceLocation EqualLoc,
                                       SourceLocation ArgLoc);
void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc);
bool SetParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                             SourceLocation EqualLoc);

// Contexts where using non-trivial C union types can be disallowed. This is
// passed to err_non_trivial_c_union_in_invalid_context.
enum NonTrivialCUnionContext {
  // Function parameter.
  NTCUC_FunctionParam,
  // Function return.
  NTCUC_FunctionReturn,
  // Default-initialized object.
  NTCUC_DefaultInitializedObject,
  // Variable with automatic storage duration.
  NTCUC_AutoVar,
  // Initializer expression that might copy from another object.
  NTCUC_CopyInit,
  // Assignment.
  NTCUC_Assignment,
  // Compound literal.
  NTCUC_CompoundLiteral,
  // Block capture.
  NTCUC_BlockCapture,
  // lvalue-to-rvalue conversion of volatile type.
  NTCUC_LValueToRValueVolatile,
};

/// Emit diagnostics if the initializer or any of its explicit or
/// implicitly-generated subexpressions require copying or
/// default-initializing a type that is or contains a C union type that is
/// non-trivial to copy or default-initialize.
void checkNonTrivialCUnionInInitializer(const Expr *Init, SourceLocation Loc);

// These flags are passed to checkNonTrivialCUnion.
enum NonTrivialCUnionKind {
  NTCUK_Init = 0x1,
  NTCUK_Destruct = 0x2,
  NTCUK_Copy = 0x4,
};

/// Emit diagnostics if a non-trivial C union type or a struct that contains
/// a non-trivial C union is used in an invalid context.
void checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
                           NonTrivialCUnionContext UseContext,
                           unsigned NonTrivialKind);

void AddInitializerToDecl(Decl *dcl, Expr *init, bool DirectInit);
void ActOnUninitializedDecl(Decl *dcl);
void ActOnInitializerError(Decl *Dcl);

void ActOnPureSpecifier(Decl *D, SourceLocation PureSpecLoc);
void ActOnCXXForRangeDecl(Decl *D);
StmtResult ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
                                      IdentifierInfo *Ident,
                                      ParsedAttributes &Attrs,
                                      SourceLocation AttrEnd);
void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc);
void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
void CheckStaticLocalForDllExport(VarDecl *VD);
void FinalizeDeclaration(Decl *D);
DeclGroupPtrTy FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
                                       ArrayRef<Decl *> Group);
DeclGroupPtrTy BuildDeclaratorGroup(MutableArrayRef<Decl *> Group);

/// Should be called on all declarations that might have attached
/// documentation comments.
void ActOnDocumentableDecl(Decl *D);
void ActOnDocumentableDecls(ArrayRef<Decl *> Group);

void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
                                     SourceLocation LocAfterDecls);
void CheckForFunctionRedefinition(
    FunctionDecl *FD, const FunctionDecl *EffectiveDefinition = nullptr,
    SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Declarator &D,
                              MultiTemplateParamsArg TemplateParamLists,
                              SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Decl *D,
                              SkipBodyInfo *SkipBody = nullptr);
void ActOnStartOfObjCMethodDef(Scope *S, Decl *D);
bool isObjCMethodDecl(Decl *D) {
  return D && isa<ObjCMethodDecl>(D);
}

/// Determine whether we can delay parsing the body of a function or
/// function template until it is used, assuming we don't care about emitting
/// code for that function.
///
/// This will be \c false if we may need the body of the function in the
/// middle of parsing an expression (where it's impractical to switch to
/// parsing a different function), for instance, if it's constexpr in C++11
/// or has an 'auto' return type in C++14. These cases are essentially bugs.
bool canDelayFunctionBody(const Declarator &D);

/// Determine whether we can skip parsing the body of a function
/// definition, assuming we don't care about analyzing its body or emitting
/// code for that function.
///
/// This will be \c false only if we may need the body of the function in
/// order to parse the rest of the program (for instance, if it is
/// \c constexpr in C++11 or has an 'auto' return type in C++14).
bool canSkipFunctionBody(Decl *D);

void computeNRVO(Stmt *Body, sema::FunctionScopeInfo *Scope);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body, bool IsInstantiation);
Decl *ActOnSkippedFunctionBody(Decl *Decl);
void ActOnFinishInlineFunctionDef(FunctionDecl *D);

/// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
/// attribute for which parsing is delayed.
void ActOnFinishDelayedAttribute(Scope *S, Decl *D, ParsedAttributes &Attrs);

/// Diagnose any unused parameters in the given sequence of
/// ParmVarDecl pointers.
void DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters);

/// Diagnose whether the size of parameters or return value of a
/// function or obj-c method definition is pass-by-value and larger than a
/// specified threshold.
void
DiagnoseSizeOfParametersAndReturnValue(ArrayRef<ParmVarDecl *> Parameters,
                                       QualType ReturnTy, NamedDecl *D);

void DiagnoseInvalidJumps(Stmt *Body);
Decl *ActOnFileScopeAsmDecl(Expr *expr,
                            SourceLocation AsmLoc,
                            SourceLocation RParenLoc);

/// Handle a C++11 empty-declaration and attribute-declaration.
Decl *ActOnEmptyDeclaration(Scope *S, const ParsedAttributesView &AttrList,
                            SourceLocation SemiLoc);

enum class ModuleDeclKind {
  Interface,      ///< 'export module X;'
  Implementation, ///< 'module X;'
};

/// The parser has processed a module-declaration that begins the definition
/// of a module interface or implementation.
DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
                               SourceLocation ModuleLoc, ModuleDeclKind MDK,
                               ModuleIdPath Path, bool IsFirstDecl);

/// The parser has processed a global-module-fragment declaration that begins
/// the definition of the global module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc);

/// The parser has processed a private-module-fragment declaration that begins
/// the definition of the private module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
/// \param PrivateLoc The location of the 'private' keyword.
DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
                                              SourceLocation PrivateLoc);

/// The parser has processed a module import declaration.
///
/// \param StartLoc The location of the first token in the declaration. This
///        could be the location of an '@', 'export', or 'import'.
/// \param ExportLoc The location of the 'export' keyword, if any.
/// \param ImportLoc The location of the 'import' keyword.
/// \param Path The module access path.
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, ModuleIdPath Path);
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, Module *M,
                             ModuleIdPath Path = {});

/// The parser has processed a module import translated from a
/// #include or similar preprocessing directive.
void ActOnModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod);

/// The parsed has entered a submodule.
void ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod);
/// The parser has left a submodule.
void ActOnModuleEnd(SourceLocation DirectiveLoc, Module *Mod);

/// Create an implicit import of the given module at the given
/// source location, for error recovery, if possible.
///
/// This routine is typically used when an entity found by name lookup
/// is actually hidden within a module that we know about but the user
/// has forgotten to import.
void createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
                                                Module *Mod);

/// Kinds of missing import. Note, the values of these enumerators correspond
/// to %select values in diagnostics.
enum class MissingImportKind {
  Declaration,
  Definition,
  DefaultArgument,
  ExplicitSpecialization,
  PartialSpecialization
};

/// Diagnose that the specified declaration needs to be visible but
/// isn't, and suggest a module import that would resolve the problem.
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           MissingImportKind MIK, bool Recover = true);
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           SourceLocation DeclLoc, ArrayRef<Module *> Modules,
                           MissingImportKind MIK, bool Recover);

Decl *ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc,
                           SourceLocation LBraceLoc);
Decl *ActOnFinishExportDecl(Scope *S, Decl *ExportDecl,
                            SourceLocation RBraceLoc);

/// We've found a use of a templated declaration that would trigger an
/// implicit instantiation. Check that any relevant explicit specializations
/// and partial specializations are visible, and diagnose if not.
void checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec);

/// We've found a use of a template specialization that would select a
/// partial specialization. Check that the partial specialization is visible,
/// and diagnose if not.
void checkPartialSpecializationVisibility(SourceLocation Loc,
                                          NamedDecl *Spec);

/// Retrieve a suitable printing policy for diagnostics.
PrintingPolicy getPrintingPolicy() const {
  return getPrintingPolicy(Context, PP);
}

/// Retrieve a suitable printing policy for diagnostics.
static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
                                        const Preprocessor &PP);

/// Scope actions.
void ActOnPopScope(SourceLocation Loc, Scope *S);
void ActOnTranslationUnitScope(Scope *S);

Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 RecordDecl *&AnonRecord);
Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 MultiTemplateParamsArg TemplateParams,
                                 bool IsExplicitInstantiation,
                                 RecordDecl *&AnonRecord);

Decl *BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
                                  AccessSpecifier AS,
                                  RecordDecl *Record,
                                  const PrintingPolicy &Policy);

Decl *BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
                                     RecordDecl *Record);

/// Common ways to introduce type names without a tag for use in diagnostics.
/// Keep in sync with err_tag_reference_non_tag.
enum NonTagKind {
  NTK_NonStruct,
  NTK_NonClass,
  NTK_NonUnion,
  NTK_NonEnum,
  NTK_Typedef,
  NTK_TypeAlias,
  NTK_Template,
  NTK_TypeAliasTemplate,
  NTK_TemplateTemplateArgument,
};

/// Given a non-tag type declaration, returns an enum useful for indicating
/// what kind of non-tag type this is.
NonTagKind getNonTagTypeDeclKind(const Decl *D, TagTypeKind TTK);

bool isAcceptableTagRedeclaration(const TagDecl *Previous,
                                  TagTypeKind NewTag, bool isDefinition,
                                  SourceLocation NewTagLoc,
                                  const IdentifierInfo *Name);

enum TagUseKind {
  TUK_Reference,   // Reference to a tag:  'struct foo *X;'
  TUK_Declaration, // Fwd decl of a tag:   'struct foo;'
  TUK_Definition,  // Definition of a tag: 'struct foo { int X; } Y;'
  TUK_Friend       // Friend declaration:  'friend struct foo;'
};

Decl *ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
               SourceLocation KWLoc, CXXScopeSpec &SS, IdentifierInfo *Name,
               SourceLocation NameLoc, const ParsedAttributesView &Attr,
               AccessSpecifier AS, SourceLocation ModulePrivateLoc,
               MultiTemplateParamsArg TemplateParameterLists, bool &OwnedDecl,
               bool &IsDependent, SourceLocation ScopedEnumKWLoc,
               bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
               bool IsTypeSpecifier, bool IsTemplateParamOrArg,
               SkipBodyInfo *SkipBody = nullptr);

Decl *ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                              unsigned TagSpec, SourceLocation TagLoc,
                              CXXScopeSpec &SS, IdentifierInfo *Name,
                              SourceLocation NameLoc,
                              const ParsedAttributesView &Attr,
                              MultiTemplateParamsArg TempParamLists);

TypeResult ActOnDependentTag(Scope *S,
                             unsigned TagSpec,
                             TagUseKind TUK,
                             const CXXScopeSpec &SS,
                             IdentifierInfo *Name,
                             SourceLocation TagLoc,
                             SourceLocation NameLoc);

void ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
               IdentifierInfo *ClassName,
               SmallVectorImpl<Decl *> &Decls);
Decl *ActOnField(Scope *S, Decl *TagD, SourceLocation DeclStart,
                 Declarator &D, Expr *BitfieldWidth);

FieldDecl *HandleField(Scope *S, RecordDecl *TagD, SourceLocation DeclStart,
                       Declarator &D, Expr *BitfieldWidth,
                       InClassInitStyle InitStyle,
                       AccessSpecifier AS);
MSPropertyDecl *HandleMSProperty(Scope *S, RecordDecl *TagD,
                                 SourceLocation DeclStart, Declarator &D,
                                 Expr *BitfieldWidth,
                                 InClassInitStyle InitStyle,
                                 AccessSpecifier AS,
                                 const ParsedAttr &MSPropertyAttr);

FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
                          TypeSourceInfo *TInfo,
                          RecordDecl *Record, SourceLocation Loc,
                          bool Mutable, Expr *BitfieldWidth,
                          InClassInitStyle InitStyle,
                          SourceLocation TSSL,
                          AccessSpecifier AS, NamedDecl *PrevDecl,
                          Declarator *D = nullptr);

bool CheckNontrivialField(FieldDecl *FD);
void DiagnoseNontrivial(const CXXRecordDecl *Record, CXXSpecialMember CSM);

enum TrivialABIHandling {
  /// The triviality of a method unaffected by "trivial_abi".
  TAH_IgnoreTrivialABI,

  /// The triviality of a method affected by "trivial_abi".
  TAH_ConsiderTrivialABI
};

bool SpecialMemberIsTrivial(CXXMethodDecl *MD, CXXSpecialMember CSM,
                            TrivialABIHandling TAH = TAH_IgnoreTrivialABI,
                            bool Diagnose = false);
CXXSpecialMember getSpecialMember(const CXXMethodDecl *MD);
void ActOnLastBitfield(SourceLocation DeclStart,
                       SmallVectorImpl<Decl *> &AllIvarDecls);
Decl *ActOnIvar(Scope *S, SourceLocation DeclStart,
                Declarator &D, Expr *BitfieldWidth,
                tok::ObjCKeywordKind visibility);

// This is used for both record definitions and ObjC interface declarations.
void ActOnFields(Scope *S, SourceLocation RecLoc, Decl *TagDecl,
                 ArrayRef<Decl *> Fields, SourceLocation LBrac,
                 SourceLocation RBrac, const ParsedAttributesView &AttrList);

/// ActOnTagStartDefinition - Invoked when we have entered the
/// scope of a tag's definition (e.g., for an enumeration, class,
/// struct, or union).
void ActOnTagStartDefinition(Scope *S, Decl *TagDecl);

/// Perform ODR-like check for C/ObjC when merging tag types from modules.
/// Differently from C++, actually parse the body and reject / error out
/// in case of a structural mismatch.
bool ActOnDuplicateDefinition(DeclSpec &DS, Decl *Prev,
                              SkipBodyInfo &SkipBody);

typedef void *SkippedDefinitionContext;

/// Invoked when we enter a tag definition that we're skipping.
SkippedDefinitionContext ActOnTagStartSkippedDefinition(Scope *S, Decl *TD);

Decl *ActOnObjCContainerStartDefinition(Decl *IDecl);

/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
/// C++ record definition's base-specifiers clause and are starting its
/// member declarations.
void ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagDecl,
                                     SourceLocation FinalLoc,
                                     bool IsFinalSpelledSealed,
                                     SourceLocation LBraceLoc);

/// ActOnTagFinishDefinition - Invoked once we have finished parsing
/// the definition of a tag (enumeration, class, struct, or union).
void ActOnTagFinishDefinition(Scope *S, Decl *TagDecl,
                              SourceRange BraceRange);

void ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context);

void ActOnObjCContainerFinishDefinition();

/// Invoked when we must temporarily exit the objective-c container
/// scope for parsing/looking-up C constructs.
///
/// Must be followed by a call to \see ActOnObjCReenterContainerContext
void ActOnObjCTemporaryExitContainerContext(DeclContext *DC);
void ActOnObjCReenterContainerContext(DeclContext *DC);

/// ActOnTagDefinitionError - Invoked when there was an unrecoverable
/// error parsing the definition of a tag.
void ActOnTagDefinitionError(Scope *S, Decl *TagDecl);

EnumConstantDecl *CheckEnumConstant(EnumDecl *Enum,
                                    EnumConstantDecl *LastEnumConst,
                                    SourceLocation IdLoc,
                                    IdentifierInfo *Id,
                                    Expr *val);
bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
                            QualType EnumUnderlyingTy, bool IsFixed,
                            const EnumDecl *Prev);

/// Determine whether the body of an anonymous enumeration should be skipped.
/// \param II The name of the first enumerator.
SkipBodyInfo shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
                                    SourceLocation IILoc);

Decl *ActOnEnumConstant(Scope *S, Decl *EnumDecl, Decl *LastEnumConstant,
                        SourceLocation IdLoc, IdentifierInfo *Id,
                        const ParsedAttributesView &Attrs,
                        SourceLocation EqualLoc, Expr *Val);
void ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
                   Decl *EnumDecl, ArrayRef<Decl *> Elements, Scope *S,
                   const ParsedAttributesView &Attr);

DeclContext *getContainingDC(DeclContext *DC);

/// Set the current declaration context until it gets popped.
void PushDeclContext(Scope *S, DeclContext *DC);
void PopDeclContext();

/// EnterDeclaratorContext - Used when we must lookup names in the context
/// of a declarator's nested name specifier.
void EnterDeclaratorContext(Scope *S, DeclContext *DC);
void ExitDeclaratorContext(Scope *S);

/// Push the parameters of D, which must be a function, into scope.
void ActOnReenterFunctionContext(Scope* S, Decl* D);
void ActOnExitFunctionContext();

DeclContext *getFunctionLevelDeclContext();

/// getCurFunctionDecl - If inside of a function body, this returns a pointer
/// to the function decl for the function being parsed.  If we're currently
/// in a 'block', this returns the containing context.
FunctionDecl *getCurFunctionDecl();

/// getCurMethodDecl - If inside of a method body, this returns a pointer to
/// the method decl for the method being parsed.  If we're currently
/// in a 'block', this returns the containing context.
ObjCMethodDecl *getCurMethodDecl();

/// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
/// or C function we're in, otherwise return null.  If we're currently
/// in a 'block', this returns the containing context.
NamedDecl *getCurFunctionOrMethodDecl();

/// Add this decl to the scope shadowed decl chains.
void PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext = true);

/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
/// true if 'D' belongs to the given declaration context.
///
/// \param AllowInlineNamespace If \c true, allow the declaration to be in the
///        enclosing namespace set of the context, rather than contained
///        directly within it.
bool isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S = nullptr,
                   bool AllowInlineNamespace = false);

/// Finds the scope corresponding to the given decl context, if it
/// happens to be an enclosing scope.  Otherwise return NULL.
static Scope *getScopeForDeclContext(Scope *S, DeclContext *DC);

/// Subroutines of ActOnDeclarator().
TypedefDecl *ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
                              TypeSourceInfo *TInfo);
bool isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New);

/// Describes the kind of merge to perform for availability
/// attributes (including "deprecated", "unavailable", and "availability").
enum AvailabilityMergeKind {
  /// Don't merge availability attributes at all.
  AMK_None,
  /// Merge availability attributes for a redeclaration, which requires
  /// an exact match.
  AMK_Redeclaration,
  /// Merge availability attributes for an override, which requires
  /// an exact match or a weakening of constraints.
  AMK_Override,
  /// Merge availability attributes for an implementation of
  /// a protocol requirement.
  AMK_ProtocolImplementation,
};

/// Describes the kind of priority given to an availability attribute.
///
/// The sum of priorities deteremines the final priority of the attribute.
/// The final priority determines how the attribute will be merged.
/// An attribute with a lower priority will always remove higher priority
/// attributes for the specified platform when it is being applied. An
/// attribute with a higher priority will not be applied if the declaration
/// already has an availability attribute with a lower priority for the
/// specified platform. The final prirority values are not expected to match
/// the values in this enumeration, but instead should be treated as a plain
/// integer value. This enumeration just names the priority weights that are
/// used to calculate that final vaue.
enum AvailabilityPriority : int {
  /// The availability attribute was specified explicitly next to the
  /// declaration.
  AP_Explicit = 0,

  /// The availability attribute was applied using '#pragma clang attribute'.
  AP_PragmaClangAttribute = 1,

  /// The availability attribute for a specific platform was inferred from
  /// an availability attribute for another platform.
  AP_InferredFromOtherPlatform = 2
};

/// Attribute merging methods. Return true if a new attribute was added.
AvailabilityAttr *
mergeAvailabilityAttr(NamedDecl *D, const AttributeCommonInfo &CI,
                      IdentifierInfo *Platform, bool Implicit,
                      VersionTuple Introduced, VersionTuple Deprecated,
                      VersionTuple Obsoleted, bool IsUnavailable,
                      StringRef Message, bool IsStrict, StringRef Replacement,
                      AvailabilityMergeKind AMK, int Priority);
TypeVisibilityAttr *
mergeTypeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                        TypeVisibilityAttr::VisibilityType Vis);
VisibilityAttr *mergeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                                    VisibilityAttr::VisibilityType Vis);
UuidAttr *mergeUuidAttr(Decl *D, const AttributeCommonInfo &CI,
                        StringRef Uuid);
DLLImportAttr *mergeDLLImportAttr(Decl *D, const AttributeCommonInfo &CI);
DLLExportAttr *mergeDLLExportAttr(Decl *D, const AttributeCommonInfo &CI);
MSInheritanceAttr *
mergeMSInheritanceAttr(Decl *D, const AttributeCommonInfo &CI, bool BestCase,
                       MSInheritanceAttr::Spelling SemanticSpelling);
FormatAttr *mergeFormatAttr(Decl *D, const AttributeCommonInfo &CI,
                            IdentifierInfo *Format, int FormatIdx,
                            int FirstArg);
SectionAttr *mergeSectionAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
CodeSegAttr *mergeCodeSegAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
AlwaysInlineAttr *mergeAlwaysInlineAttr(Decl *D,
                                        const AttributeCommonInfo &CI,
                                        const IdentifierInfo *Ident);
MinSizeAttr *mergeMinSizeAttr(Decl *D, const AttributeCommonInfo &CI);
NoSpeculativeLoadHardeningAttr *
mergeNoSpeculativeLoadHardeningAttr(Decl *D,
                                    const NoSpeculativeLoadHardeningAttr &AL);
SpeculativeLoadHardeningAttr *
mergeSpeculativeLoadHardeningAttr(Decl *D,
                                  const SpeculativeLoadHardeningAttr &AL);
OptimizeNoneAttr *mergeOptimizeNoneAttr(Decl *D,
                                        const AttributeCommonInfo &CI);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D, const ParsedAttr &AL);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D,
                                              const InternalLinkageAttr &AL);
CommonAttr *mergeCommonAttr(Decl *D, const ParsedAttr &AL);
CommonAttr *mergeCommonAttr(Decl *D, const CommonAttr &AL);

void mergeDeclAttributes(NamedDecl *New, Decl *Old,
                         AvailabilityMergeKind AMK = AMK_Redeclaration);
void MergeTypedefNameDecl(Scope *S, TypedefNameDecl *New,
                          LookupResult &OldDecls);
bool MergeFunctionDecl(FunctionDecl *New, NamedDecl *&Old, Scope *S,
                       bool MergeTypeWithOld);
bool MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
                                  Scope *S, bool MergeTypeWithOld);
void mergeObjCMethodDecls(ObjCMethodDecl *New, ObjCMethodDecl *Old);
void MergeVarDecl(VarDecl *New, LookupResult &Previous);
void MergeVarDeclTypes(VarDecl *New, VarDecl *Old, bool MergeTypeWithOld);
void MergeVarDeclExceptionSpecs(VarDecl *New, VarDecl *Old);
bool checkVarDeclRedefinition(VarDecl *OldDefn, VarDecl *NewDefn);
void notePreviousDefinition(const NamedDecl *Old, SourceLocation New);
bool MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old, Scope *S);

// AssignmentAction - This is used by all the assignment diagnostic functions
// to represent what is actually causing the operation
enum AssignmentAction {
  AA_Assigning,
  AA_Passing,
  AA_Returning,
  AA_Converting,
  AA_Initializing,
  AA_Sending,
  AA_Casting,
  AA_Passing_CFAudited
};

/// C++ Overloading.
enum OverloadKind {
  /// This is a legitimate overload: the existing declarations are
  /// functions or function templates with different signatures.
  Ovl_Overload,

  /// This is not an overload because the signature exactly matches
  /// an existing declaration.
  Ovl_Match,

  /// This is not an overload because the lookup results contain a
  /// non-function.
  Ovl_NonFunction
};
OverloadKind CheckOverload(Scope *S,
                           FunctionDecl *New,
                           const LookupResult &OldDecls,
                           NamedDecl *&OldDecl,
                           bool IsForUsingDecl);
bool IsOverload(FunctionDecl *New, FunctionDecl *Old, bool IsForUsingDecl,
                bool ConsiderCudaAttrs = true);

ImplicitConversionSequence
TryImplicitConversion(Expr *From, QualType ToType,
                      bool SuppressUserConversions,
                      bool AllowExplicit,
                      bool InOverloadResolution,
                      bool CStyle,
                      bool AllowObjCWritebackConversion);

bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
bool IsComplexPromotion(QualType FromType, QualType ToType);
bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
                         bool InOverloadResolution,
                         QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCPointerConversion(QualType FromType, QualType ToType,
                             QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCWritebackConversion(QualType FromType, QualType ToType,
                               QualType &ConvertedType);
bool IsBlockPointerConversion(QualType FromType, QualType ToType,
                              QualType& ConvertedType);
bool FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
                                const FunctionProtoType *NewType,
                                unsigned *ArgPos = nullptr);
void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
                                QualType FromType, QualType ToType);

void maybeExtendBlockObject(ExprResult &E);
CastKind PrepareCastToObjCObjectPointer(ExprResult &E);
bool CheckPointerConversion(Expr *From, QualType ToType,
                            CastKind &Kind,
                            CXXCastPath& BasePath,
                            bool IgnoreBaseAccess,
                            bool Diagnose = true);
bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
                               bool InOverloadResolution,
                               QualType &ConvertedType);
bool CheckMemberPointerConversion(Expr *From, QualType ToType,
                                  CastKind &Kind,
                                  CXXCastPath &BasePath,
                                  bool IgnoreBaseAccess);
bool IsQualificationConversion(QualType FromType, QualType ToType,
                               bool CStyle, bool &ObjCLifetimeConversion);
bool IsFunctionConversion(QualType FromType, QualType ToType,
                          QualType &ResultTy);
bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);
bool isSameOrCompatibleFunctionType(CanQualType Param, CanQualType Arg);

ExprResult PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
                                           const VarDecl *NRVOCandidate,
                                           QualType ResultType,
                                           Expr *Value,
                                           bool AllowNRVO = true);

bool CanPerformAggregateInitializationForOverloadResolution(
    const InitializedEntity &Entity, InitListExpr *From);

bool CanPerformCopyInitialization(const InitializedEntity &Entity,
                                  ExprResult Init);
ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
                                     SourceLocation EqualLoc,
                                     ExprResult Init,
                                     bool TopLevelOfInitList = false,
                                     bool AllowExplicit = false);
ExprResult PerformObjectArgumentInitialization(Expr *From,
                                               NestedNameSpecifier *Qualifier,
                                               NamedDecl *FoundDecl,
                                               CXXMethodDecl *Method);

/// Check that the lifetime of the initializer (and its subobjects) is
/// sufficient for initializing the entity, and perform lifetime extension
/// (when permitted) if not.
void checkInitializerLifetime(const InitializedEntity &Entity, Expr *Init);

ExprResult PerformContextuallyConvertToBool(Expr *From);
ExprResult PerformContextuallyConvertToObjCPointer(Expr *From);

/// Contexts in which a converted constant expression is required.
enum CCEKind {
  CCEK_CaseValue,   ///< Expression in a case label.
  CCEK_Enumerator,  ///< Enumerator value with fixed underlying type.
  CCEK_TemplateArg, ///< Value of a non-type template parameter.
  CCEK_NewExpr,     ///< Constant expression in a noptr-new-declarator.
  CCEK_ConstexprIf, ///< Condition in a constexpr if statement.
  CCEK_ExplicitBool ///< Condition in an explicit(bool) specifier.
};
ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                            llvm::APSInt &Value, CCEKind CCE);
ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                            APValue &Value, CCEKind CCE);

/// Abstract base class used to perform a contextual implicit
/// conversion from an expression to any type passing a filter.
class ContextualImplicitConverter {
public:
  bool Suppress;
  bool SuppressConversion;

  ContextualImplicitConverter(bool Suppress = false,
                              bool SuppressConversion = false)
      : Suppress(Suppress), SuppressConversion(SuppressConversion) {}

  /// Determine whether the specified type is a valid destination type
  /// for this conversion.
  virtual bool match(QualType T) = 0;

  /// Emits a diagnostic complaining that the expression does not have
  /// integral or enumeration type.
  virtual SemaDiagnosticBuilder
  diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a diagnostic when the expression has incomplete class type.
  virtual SemaDiagnosticBuilder
  diagnoseIncomplete(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a diagnostic when the only matching conversion function
  /// is explicit.
  virtual SemaDiagnosticBuilder diagnoseExplicitConv(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;

  /// Emits a note for the explicit conversion function.
  virtual SemaDiagnosticBuilder
  noteExplicitConv(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;

  /// Emits a diagnostic when there are multiple possible conversion
  /// functions.
  virtual SemaDiagnosticBuilder
  diagnoseAmbiguous(Sema &S, SourceLocation Loc, QualType T) = 0;

  /// Emits a note for one of the candidate conversions.
  virtual SemaDiagnosticBuilder
  noteAmbiguous(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;

  /// Emits a diagnostic when we picked a conversion function
  /// (for cases when we are not allowed to pick a conversion function).
  virtual SemaDiagnosticBuilder diagnoseConversion(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;

  virtual ~ContextualImplicitConverter() {}
};

class ICEConvertDiagnoser : public ContextualImplicitConverter {
  bool AllowScopedEnumerations;

public:
  ICEConvertDiagnoser(bool AllowScopedEnumerations,
                      bool Suppress, bool SuppressConversion)
      : ContextualImplicitConverter(Suppress, SuppressConversion),
        AllowScopedEnumerations(AllowScopedEnumerations) {}

  /// Match an integral or (possibly scoped) enumeration type.
  bool match(QualType T) override;

  SemaDiagnosticBuilder
  diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) override {
    return diagnoseNotInt(S, Loc, T);
  }

  /// Emits a diagnostic complaining that the expression does not have
  /// integral or enumeration type.
  virtual SemaDiagnosticBuilder
  diagnoseNotInt(Sema &S, SourceLocation Loc, QualType T) = 0;
};

/// Perform a contextual implicit conversion.
ExprResult PerformContextualImplicitConversion(
    SourceLocation Loc, Expr *FromE, ContextualImplicitConverter &Converter);


enum ObjCSubscriptKind {
  OS_Array,
  OS_Dictionary,
  OS_Error
};
ObjCSubscriptKind CheckSubscriptingKind(Expr *FromE);

// Note that LK_String is intentionally after the other literals, as
// this is used for diagnostics logic.
enum ObjCLiteralKind {
  LK_Array,
  LK_Dictionary,
  LK_Numeric,
  LK_Boxed,
  LK_String,
  LK_Block,
  LK_None
};
ObjCLiteralKind CheckLiteralKind(Expr *FromE);

ExprResult PerformObjectMemberConversion(Expr *From,
                                         NestedNameSpecifier *Qualifier,
                                         NamedDecl *FoundDecl,
                                         NamedDecl *Member);

// Members have to be NamespaceDecl* or TranslationUnitDecl*.
// TODO: make this is a typesafe union.
typedef llvm::SmallSetVector<DeclContext   *, 16> AssociatedNamespaceSet;
typedef llvm::SmallSetVector<CXXRecordDecl *, 16> AssociatedClassSet;

using ADLCallKind = CallExpr::ADLCallKind;

void AddOverloadCandidate(FunctionDecl *Function, DeclAccessPair FoundDecl,
                          ArrayRef<Expr *> Args,
                          OverloadCandidateSet &CandidateSet,
                          bool SuppressUserConversions = false,
                          bool PartialOverloading = false,
                          bool AllowExplicit = true,
                          bool AllowExplicitConversion = false,
                          ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
                          ConversionSequenceList EarlyConversions = None);
void AddFunctionCandidates(const UnresolvedSetImpl &Functions,
                    ArrayRef<Expr *> Args,
                    OverloadCandidateSet &CandidateSet,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr,
                    bool SuppressUserConversions = false,
                    bool PartialOverloading = false,
                    bool FirstArgumentIsBase = false);
void AddMethodCandidate(DeclAccessPair FoundDecl,
                        QualType ObjectType,
                        Expr::Classification ObjectClassification,
                        ArrayRef<Expr *> Args,
                        OverloadCandidateSet& CandidateSet,
                        bool SuppressUserConversion = false);
void AddMethodCandidate(CXXMethodDecl *Method,
                        DeclAccessPair FoundDecl,
                        CXXRecordDecl *ActingContext, QualType ObjectType,
                        Expr::Classification ObjectClassification,
                        ArrayRef<Expr *> Args,
                        OverloadCandidateSet& CandidateSet,
                        bool SuppressUserConversions = false,
                        bool PartialOverloading = false,
                        ConversionSequenceList EarlyConversions = None);
void AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
                                DeclAccessPair FoundDecl,
                                CXXRecordDecl *ActingContext,
                               TemplateArgumentListInfo *ExplicitTemplateArgs,
                                QualType ObjectType,
                                Expr::Classification ObjectClassification,
                                ArrayRef<Expr *> Args,
                                OverloadCandidateSet& CandidateSet,
                                bool SuppressUserConversions = false,
                                bool PartialOverloading = false);
void AddTemplateOverloadCandidate(
    FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
    TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
    OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
    bool PartialOverloading = false, bool AllowExplicit = true,
    ADLCallKind IsADLCandidate = ADLCallKind::NotADL);
bool CheckNonDependentConversions(FunctionTemplateDecl *FunctionTemplate,
                                  ArrayRef<QualType> ParamTypes,
                                  ArrayRef<Expr *> Args,
                                  OverloadCandidateSet &CandidateSet,
                                  ConversionSequenceList &Conversions,
                                  bool SuppressUserConversions,
                                  CXXRecordDecl *ActingContext = nullptr,
                                  QualType ObjectType = QualType(),
                                  Expr::Classification
                                      ObjectClassification = {});
void AddConversionCandidate(
    CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
    CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
    OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
    bool AllowExplicit, bool AllowResultConversion = true);
void AddTemplateConversionCandidate(
    FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
    CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
    OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
    bool AllowExplicit, bool AllowResultConversion = true);
void AddSurrogateCandidate(CXXConversionDecl *Conversion,
                           DeclAccessPair FoundDecl,
                           CXXRecordDecl *ActingContext,
                           const FunctionProtoType *Proto,
                           Expr *Object, ArrayRef<Expr *> Args,
                           OverloadCandidateSet& CandidateSet);
void AddMemberOperatorCandidates(OverloadedOperatorKind Op,
                                 SourceLocation OpLoc, ArrayRef<Expr *> Args,
                                 OverloadCandidateSet& CandidateSet,
                                 SourceRange OpRange = SourceRange());
void AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
                         OverloadCandidateSet& CandidateSet,
                         bool IsAssignmentOperator = false,
                         unsigned NumContextualBoolArguments = 0);
void AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
                                  SourceLocation OpLoc, ArrayRef<Expr *> Args,
                                  OverloadCandidateSet& CandidateSet);
void AddArgumentDependentLookupCandidates(DeclarationName Name,
                                          SourceLocation Loc,
                                          ArrayRef<Expr *> Args,
                              TemplateArgumentListInfo *ExplicitTemplateArgs,
                                          OverloadCandidateSet& CandidateSet,
                                          bool PartialOverloading = false);

// Emit as a 'note' the specific overload candidate
void NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn,
                           QualType DestType = QualType(),
                           bool TakingAddress = false);

// Emit as a series of 'note's all template and non-templates identified by
// the expression Expr
void NoteAllOverloadCandidates(Expr *E, QualType DestType = QualType(),
                               bool TakingAddress = false);

/// Check the enable_if expressions on the given function. Returns the first
/// failing attribute, or NULL if they were all successful.
EnableIfAttr *CheckEnableIf(FunctionDecl *Function, ArrayRef<Expr *> Args,
                            bool MissingImplicitThis = false);

/// Find the failed Boolean condition within a given Boolean
/// constant expression, and describe it with a string.
std::pair<Expr *, std::string> findFailedBooleanCondition(Expr *Cond);

/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
/// non-ArgDependent DiagnoseIfAttrs.
///
/// Argument-dependent diagnose_if attributes should be checked each time a
/// function is used as a direct callee of a function call.
///
/// Returns true if any errors were emitted.
bool diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
                                         const Expr *ThisArg,
                                         ArrayRef<const Expr *> Args,
                                         SourceLocation Loc);

/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
/// ArgDependent DiagnoseIfAttrs.
///
/// Argument-independent diagnose_if attributes should be checked on every use
/// of a function.
///
/// Returns true if any errors were emitted.
bool diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
                                           SourceLocation Loc);

/// Returns whether the given function's address can be taken or not,
/// optionally emitting a diagnostic if the address can't be taken.
///
/// Returns false if taking the address of the function is illegal.
bool checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
                                       bool Complain = false,
                                       SourceLocation Loc = SourceLocation());

// [PossiblyAFunctionType]  -->   [Return]
// NonFunctionType --> NonFunctionType
// R (A) --> R(A)
// R (*)(A) --> R (A)
// R (&)(A) --> R (A)
// R (S::*)(A) --> R (A)
QualType ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType);

FunctionDecl *
ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
                                   QualType TargetType,
                                   bool Complain,
                                   DeclAccessPair &Found,
                                   bool *pHadMultipleCandidates = nullptr);

FunctionDecl *
resolveAddressOfOnlyViableOverloadCandidate(Expr *E,
                                            DeclAccessPair &FoundResult);

bool resolveAndFixAddressOfOnlyViableOverloadCandidate(
    ExprResult &SrcExpr, bool DoFunctionPointerConversion = false);

FunctionDecl *
ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
                                            bool Complain = false,
                                            DeclAccessPair *Found = nullptr);

bool ResolveAndFixSingleFunctionTemplateSpecialization(
                    ExprResult &SrcExpr,
                    bool DoFunctionPointerConverion = false,
                    bool Complain = false,
                    SourceRange OpRangeForComplaining = SourceRange(),
                    QualType DestTypeForComplaining = QualType(),
                    unsigned DiagIDForComplaining = 0);


Expr *FixOverloadedFunctionReference(Expr *E,
                                     DeclAccessPair FoundDecl,
                                     FunctionDecl *Fn);
ExprResult FixOverloadedFunctionReference(ExprResult,
                                          DeclAccessPair FoundDecl,
                                          FunctionDecl *Fn);

void AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
                                 ArrayRef<Expr *> Args,
                                 OverloadCandidateSet &CandidateSet,
                                 bool PartialOverloading = false);

// An enum used to represent the different possible results of building a
// range-based for loop.
enum ForRangeStatus {
  FRS_Success,
  FRS_NoViableFunction,
  FRS_DiagnosticIssued
};

ForRangeStatus BuildForRangeBeginEndCall(SourceLocation Loc,
                                         SourceLocation RangeLoc,
                                         const DeclarationNameInfo &NameInfo,
                                         LookupResult &MemberLookup,
                                         OverloadCandidateSet *CandidateSet,
                                         Expr *Range, ExprResult *CallExpr);

ExprResult BuildOverloadedCallExpr(Scope *S, Expr *Fn,
                                   UnresolvedLookupExpr *ULE,
                                   SourceLocation LParenLoc,
                                   MultiExprArg Args,
                                   SourceLocation RParenLoc,
                                   Expr *ExecConfig,
                                   bool AllowTypoCorrection=true,
                                   bool CalleesAddressIsTaken=false);

bool buildOverloadedCallSet(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE,
                            MultiExprArg Args, SourceLocation RParenLoc,
                            OverloadCandidateSet *CandidateSet,
                            ExprResult *Result);

ExprResult CreateOverloadedUnaryOp(SourceLocation OpLoc,
                                   UnaryOperatorKind Opc,
                                   const UnresolvedSetImpl &Fns,
                                   Expr *input, bool RequiresADL = true);

ExprResult CreateOverloadedBinOp(SourceLocation OpLoc,
                                 BinaryOperatorKind Opc,
                                 const UnresolvedSetImpl &Fns,
                                 Expr *LHS, Expr *RHS,
                                 bool RequiresADL = true);

ExprResult CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
                                              SourceLocation RLoc,
                                              Expr *Base,Expr *Idx);

ExprResult
BuildCallToMemberFunction(Scope *S, Expr *MemExpr,
                          SourceLocation LParenLoc,
                          MultiExprArg Args,
                          SourceLocation RParenLoc);
ExprResult
BuildCallToObjectOfClassType(Scope *S, Expr *Object, SourceLocation LParenLoc,
                             MultiExprArg Args,
                             SourceLocation RParenLoc);

ExprResult BuildOverloadedArrowExpr(Scope *S, Expr *Base,
                                    SourceLocation OpLoc,
                                    bool *NoArrowOperatorFound = nullptr);

/// CheckCallReturnType - Checks that a call expression's return type is
/// complete. Returns true on failure. The location passed in is the location
/// that best represents the call.
bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
                         CallExpr *CE, FunctionDecl *FD);

/// Helpers for dealing with blocks and functions.
bool CheckParmsForFunctionDef(ArrayRef<ParmVarDecl *> Parameters,
                              bool CheckParameterNames);
void CheckCXXDefaultArguments(FunctionDecl *FD);
void CheckExtraCXXDefaultArguments(Declarator &D);
Scope *getNonFieldDeclScope(Scope *S);

/// \name Name lookup
///
/// These routines provide name lookup that is used during semantic
/// analysis to resolve the various kinds of names (identifiers,
/// overloaded operator names, constructor names, etc.) into zero or
/// more declarations within a particular scope. The major entry
/// points are LookupName, which performs unqualified name lookup,
/// and LookupQualifiedName, which performs qualified name lookup.
///
/// All name lookup is performed based on some specific criteria,
/// which specify what names will be visible to name lookup and how
/// far name lookup should work. These criteria are important both
/// for capturing language semantics (certain lookups will ignore
/// certain names, for example) and for performance, since name
/// lookup is often a bottleneck in the compilation of C++. Name
/// lookup criteria is specified via the LookupCriteria enumeration.
///
/// The results of name lookup can vary based on the kind of name
/// lookup performed, the current language, and the translation
/// unit. In C, for example, name lookup will either return nothing
/// (no entity found) or a single declaration. In C++, name lookup
/// can additionally refer to a set of overloaded functions or
/// result in an ambiguity. All of the possible results of name
/// lookup are captured by the LookupResult class, which provides
/// the ability to distinguish among them.
//@{

/// Describes the kind of name lookup to perform.
enum LookupNameKind {
  /// Ordinary name lookup, which finds ordinary names (functions,
  /// variables, typedefs, etc.) in C and most kinds of names
  /// (functions, variables, members, types, etc.) in C++.
  LookupOrdinaryName = 0,
  /// Tag name lookup, which finds the names of enums, classes,
  /// structs, and unions.
  LookupTagName,
  /// Label name lookup.
  LookupLabel,
  /// Member name lookup, which finds the names of
  /// class/struct/union members.
  LookupMemberName,
  /// Look up of an operator name (e.g., operator+) for use with
  /// operator overloading. This lookup is similar to ordinary name
  /// lookup, but will ignore any declarations that are class members.
  LookupOperatorName,
  /// Look up of a name that precedes the '::' scope resolution
  /// operator in C++. This lookup completely ignores operator, object,
  /// function, and enumerator names (C++ [basic.lookup.qual]p1).
  LookupNestedNameSpecifierName,
  /// Look up a namespace name within a C++ using directive or
  /// namespace alias definition, ignoring non-namespace names (C++
  /// [basic.lookup.udir]p1).
  LookupNamespaceName,
  /// Look up all declarations in a scope with the given name,
  /// including resolved using declarations.  This is appropriate
  /// for checking redeclarations for a using declaration.
  LookupUsingDeclName,
  /// Look up an ordinary name that is going to be redeclared as a
  /// name with linkage. This lookup ignores any declarations that
  /// are outside of the current scope unless they have linkage. See
  /// C99 6.2.2p4-5 and C++ [basic.link]p6.
  LookupRedeclarationWithLinkage,
  /// Look up a friend of a local class. This lookup does not look
  /// outside the innermost non-class scope. See C++11 [class.friend]p11.
  LookupLocalFriendName,
  /// Look up the name of an Objective-C protocol.
  LookupObjCProtocolName,
  /// Look up implicit 'self' parameter of an objective-c method.
  LookupObjCImplicitSelfParam,
  /// Look up the name of an OpenMP user-defined reduction operation.
  LookupOMPReductionName,
  /// Look up the name of an OpenMP user-defined mapper.
  LookupOMPMapperName,
  /// Look up any declaration with any name.
  LookupAnyName
};

/// Specifies whether (or how) name lookup is being performed for a
/// redeclaration (vs. a reference).
enum RedeclarationKind {
  /// The lookup is a reference to this name that is not for the
  /// purpose of redeclaring the name.
  NotForRedeclaration = 0,
  /// The lookup results will be used for redeclaration of a name,
  /// if an entity by that name already exists and is visible.
  ForVisibleRedeclaration,
  /// The lookup results will be used for redeclaration of a name
  /// with external linkage; non-visible lookup results with external linkage
  /// may also be found.
  ForExternalRedeclaration
};

RedeclarationKind forRedeclarationInCurContext() {
  // A declaration with an owning module for linkage can never link against
  // anything that is not visible. We don't need to check linkage here; if
  // the context has internal linkage, redeclaration lookup won't find things
  // from other TUs, and we can't safely compute linkage yet in general.
  if (cast<Decl>(CurContext)
          ->getOwningModuleForLinkage(/*IgnoreLinkage*/true))
    return ForVisibleRedeclaration;
  return ForExternalRedeclaration;
}

/// The possible outcomes of name lookup for a literal operator.
enum LiteralOperatorLookupResult {
  /// The lookup resulted in an error.
  LOLR_Error,
  /// The lookup found no match but no diagnostic was issued.
  LOLR_ErrorNoDiagnostic,
  /// The lookup found a single 'cooked' literal operator, which
  /// expects a normal literal to be built and passed to it.
  LOLR_Cooked,
  /// The lookup found a single 'raw' literal operator, which expects
  /// a string literal containing the spelling of the literal token.
  LOLR_Raw,
  /// The lookup found an overload set of literal operator templates,
  /// which expect the characters of the spelling of the literal token to be
  /// passed as a non-type template argument pack.
  LOLR_Template,
  /// The lookup found an overload set of literal operator templates,
  /// which expect the character type and characters of the spelling of the
  /// string literal token to be passed as template arguments.
  LOLR_StringTemplate
};

SpecialMemberOverloadResult LookupSpecialMember(CXXRecordDecl *D,
                                                CXXSpecialMember SM,
                                                bool ConstArg,
                                                bool VolatileArg,
                                                bool RValueThis,
                                                bool ConstThis,
                                                bool VolatileThis);

typedef std::function<void(const TypoCorrection &)> TypoDiagnosticGenerator;
typedef std::function<ExprResult(Sema &, TypoExpr *, TypoCorrection)>
    TypoRecoveryCallback;

3408private:
bool CppLookupName(LookupResult &R, Scope *S);

struct TypoExprState {
  std::unique_ptr<TypoCorrectionConsumer> Consumer;
  TypoDiagnosticGenerator DiagHandler;
  TypoRecoveryCallback RecoveryHandler;
  TypoExprState();
  TypoExprState(TypoExprState &&other) noexcept;
  TypoExprState &operator=(TypoExprState &&other) noexcept;
};

/// The set of unhandled TypoExprs and their associated state.
llvm::MapVector<TypoExpr *, TypoExprState> DelayedTypos;

/// Creates a new TypoExpr AST node.
TypoExpr *createDelayedTypo(std::unique_ptr<TypoCorrectionConsumer> TCC,
                            TypoDiagnosticGenerator TDG,
                            TypoRecoveryCallback TRC);

// The set of known/encountered (unique, canonicalized) NamespaceDecls.
//
// The boolean value will be true to indicate that the namespace was loaded
// from an AST/PCH file, or false otherwise.
llvm::MapVector<NamespaceDecl*, bool> KnownNamespaces;

/// Whether we have already loaded known namespaces from an extenal
/// source.
bool LoadedExternalKnownNamespaces;

/// Helper for CorrectTypo and CorrectTypoDelayed used to create and
/// populate a new TypoCorrectionConsumer. Returns nullptr if typo correction
/// should be skipped entirely.
std::unique_ptr<TypoCorrectionConsumer>
makeTypoCorrectionConsumer(const DeclarationNameInfo &Typo,
                           Sema::LookupNameKind LookupKind, Scope *S,
                           CXXScopeSpec *SS,
                           CorrectionCandidateCallback &CCC,
                           DeclContext *MemberContext, bool EnteringContext,
                           const ObjCObjectPointerType *OPT,
                           bool ErrorRecovery);

3450public:
const TypoExprState &getTypoExprState(TypoExpr *TE) const;

/// Clears the state of the given TypoExpr.
void clearDelayedTypo(TypoExpr *TE);

/// Look up a name, looking for a single declaration.  Return
/// null if the results were absent, ambiguous, or overloaded.
///
/// It is preferable to use the elaborated form and explicitly handle
/// ambiguity and overloaded.
NamedDecl *LookupSingleName(Scope *S, DeclarationName Name,
                            SourceLocation Loc,
                            LookupNameKind NameKind,
                            RedeclarationKind Redecl
                              = NotForRedeclaration);
bool LookupBuiltin(LookupResult &R);
bool LookupName(LookupResult &R, Scope *S,
                bool AllowBuiltinCreation = false);
bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
                         bool InUnqualifiedLookup = false);
bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
                         CXXScopeSpec &SS);
bool LookupParsedName(LookupResult &R, Scope *S, CXXScopeSpec *SS,
                      bool AllowBuiltinCreation = false,
                      bool EnteringContext = false);
ObjCProtocolDecl *LookupProtocol(IdentifierInfo *II, SourceLocation IdLoc,
                                 RedeclarationKind Redecl
                                   = NotForRedeclaration);
bool LookupInSuper(LookupResult &R, CXXRecordDecl *Class);

void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
                                  QualType T1, QualType T2,
                                  UnresolvedSetImpl &Functions);

LabelDecl *LookupOrCreateLabel(IdentifierInfo *II, SourceLocation IdentLoc,
                               SourceLocation GnuLabelLoc = SourceLocation());

DeclContextLookupResult LookupConstructors(CXXRecordDecl *Class);
CXXConstructorDecl *LookupDefaultConstructor(CXXRecordDecl *Class);
CXXConstructorDecl *LookupCopyingConstructor(CXXRecordDecl *Class,
                                             unsigned Quals);
CXXMethodDecl *LookupCopyingAssignment(CXXRecordDecl *Class, unsigned Quals,
                                       bool RValueThis, unsigned ThisQuals);
CXXConstructorDecl *LookupMovingConstructor(CXXRecordDecl *Class,
                                            unsigned Quals);
CXXMethodDecl *LookupMovingAssignment(CXXRecordDecl *Class, unsigned Quals,
                                      bool RValueThis, unsigned ThisQuals);
CXXDestructorDecl *LookupDestructor(CXXRecordDecl *Class);

bool checkLiteralOperatorId(const CXXScopeSpec &SS, const UnqualifiedId &Id);
LiteralOperatorLookupResult LookupLiteralOperator(Scope *S, LookupResult &R,
                                                  ArrayRef<QualType> ArgTys,
                                                  bool AllowRaw,
                                                  bool AllowTemplate,
                                                  bool AllowStringTemplate,
                                                  bool DiagnoseMissing);
bool isKnownName(StringRef name);

/// Status of the function emission on the CUDA/HIP/OpenMP host/device attrs.
enum class FunctionEmissionStatus {
  Emitted,
  CUDADiscarded,     // Discarded due to CUDA/HIP hostness
  OMPDiscarded,      // Discarded due to OpenMP hostness
  TemplateDiscarded, // Discarded due to uninstantiated templates
  Unknown,
};
FunctionEmissionStatus getEmissionStatus(FunctionDecl *Decl);

// Whether the callee should be ignored in CUDA/HIP/OpenMP host/device check.
bool shouldIgnoreInHostDeviceCheck(FunctionDecl *Callee);

void ArgumentDependentLookup(DeclarationName Name, SourceLocation Loc,
                             ArrayRef<Expr *> Args, ADLResult &Functions);

void LookupVisibleDecls(Scope *S, LookupNameKind Kind,
                        VisibleDeclConsumer &Consumer,
                        bool IncludeGlobalScope = true,
                        bool LoadExternal = true);
void LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
                        VisibleDeclConsumer &Consumer,
                        bool IncludeGlobalScope = true,
                        bool IncludeDependentBases = false,
                        bool LoadExternal = true);

enum CorrectTypoKind {
  CTK_NonError,     // CorrectTypo used in a non error recovery situation.
  CTK_ErrorRecovery // CorrectTypo used in normal error recovery.
};

TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
                           Sema::LookupNameKind LookupKind,
                           Scope *S, CXXScopeSpec *SS,
                           CorrectionCandidateCallback &CCC,
                           CorrectTypoKind Mode,
                           DeclContext *MemberContext = nullptr,
                           bool EnteringContext = false,
                           const ObjCObjectPointerType *OPT = nullptr,
                           bool RecordFailure = true);

TypoExpr *CorrectTypoDelayed(const DeclarationNameInfo &Typo,
                             Sema::LookupNameKind LookupKind, Scope *S,
                             CXXScopeSpec *SS,
                             CorrectionCandidateCallback &CCC,
                             TypoDiagnosticGenerator TDG,
                             TypoRecoveryCallback TRC, CorrectTypoKind Mode,
                             DeclContext *MemberContext = nullptr,
                             bool EnteringContext = false,
                             const ObjCObjectPointerType *OPT = nullptr);

/// Process any TypoExprs in the given Expr and its children,
/// generating diagnostics as appropriate and returning a new Expr if there
/// were typos that were all successfully corrected and ExprError if one or
/// more typos could not be corrected.
///
/// \param E The Expr to check for TypoExprs.
///
/// \param InitDecl A VarDecl to avoid because the Expr being corrected is its
/// initializer.
///
/// \param Filter A function applied to a newly rebuilt Expr to determine if
/// it is an acceptable/usable result from a single combination of typo
/// corrections. As long as the filter returns ExprError, different
/// combinations of corrections will be tried until all are exhausted.
ExprResult
CorrectDelayedTyposInExpr(Expr *E, VarDecl *InitDecl = nullptr,
                          llvm::function_ref<ExprResult(Expr *)> Filter =
                              [](Expr *E) -> ExprResult { return E; });

ExprResult
CorrectDelayedTyposInExpr(Expr *E,
                          llvm::function_ref<ExprResult(Expr *)> Filter) {
  return CorrectDelayedTyposInExpr(E, nullptr, Filter);
}

ExprResult
CorrectDelayedTyposInExpr(ExprResult ER, VarDecl *InitDecl = nullptr,
                          llvm::function_ref<ExprResult(Expr *)> Filter =
                              [](Expr *E) -> ExprResult { return E; }) {
  return ER.isInvalid() ? ER : CorrectDelayedTyposInExpr(ER.get(), Filter);
}

ExprResult
CorrectDelayedTyposInExpr(ExprResult ER,
                          llvm::function_ref<ExprResult(Expr *)> Filter) {
  return CorrectDelayedTyposInExpr(ER, nullptr, Filter);
}

void diagnoseTypo(const TypoCorrection &Correction,
                  const PartialDiagnostic &TypoDiag,
                  bool ErrorRecovery = true);

void diagnoseTypo(const TypoCorrection &Correction,
                  const PartialDiagnostic &TypoDiag,
                  const PartialDiagnostic &PrevNote,
                  bool ErrorRecovery = true);

void MarkTypoCorrectedFunctionDefinition(const NamedDecl *F);

void FindAssociatedClassesAndNamespaces(SourceLocation InstantiationLoc,
                                        ArrayRef<Expr *> Args,
                                 AssociatedNamespaceSet &AssociatedNamespaces,
                                 AssociatedClassSet &AssociatedClasses);

void FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
                          bool ConsiderLinkage, bool AllowInlineNamespace);

bool CheckRedeclarationModuleOwnership(NamedDecl *New, NamedDecl *Old);

void DiagnoseAmbiguousLookup(LookupResult &Result);
//@}

ObjCInterfaceDecl *getObjCInterfaceDecl(IdentifierInfo *&Id,
                                        SourceLocation IdLoc,
                                        bool TypoCorrection = false);
NamedDecl *LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
                               Scope *S, bool ForRedeclaration,
                               SourceLocation Loc);
NamedDecl *ImplicitlyDefineFunction(SourceLocation Loc, IdentifierInfo &II,
                                    Scope *S);
void AddKnownFunctionAttributes(FunctionDecl *FD);

// More parsing and symbol table subroutines.

void ProcessPragmaWeak(Scope *S, Decl *D);
// Decl attributes - this routine is the top level dispatcher.
void ProcessDeclAttributes(Scope *S, Decl *D, const Declarator &PD);
// Helper for delayed processing of attributes.
void ProcessDeclAttributeDelayed(Decl *D,
                                 const ParsedAttributesView &AttrList);
void ProcessDeclAttributeList(Scope *S, Decl *D, const ParsedAttributesView &AL,
                           bool IncludeCXX11Attributes = true);
bool ProcessAccessDeclAttributeList(AccessSpecDecl *ASDecl,
                                 const ParsedAttributesView &AttrList);

void checkUnusedDeclAttributes(Declarator &D);

/// Determine if type T is a valid subject for a nonnull and similar
/// attributes. By default, we look through references (the behavior used by
/// nonnull), but if the second parameter is true, then we treat a reference
/// type as valid.
bool isValidPointerAttrType(QualType T, bool RefOkay = false);

bool CheckRegparmAttr(const ParsedAttr &attr, unsigned &value);
bool CheckCallingConvAttr(const ParsedAttr &attr, CallingConv &CC,
                          const FunctionDecl *FD = nullptr);
bool CheckAttrTarget(const ParsedAttr &CurrAttr);
bool CheckAttrNoArgs(const ParsedAttr &CurrAttr);
bool checkStringLiteralArgumentAttr(const ParsedAttr &Attr, unsigned ArgNum,
                                    StringRef &Str,
                                    SourceLocation *ArgLocation = nullptr);
bool checkSectionName(SourceLocation LiteralLoc, StringRef Str);
bool checkTargetAttr(SourceLocation LiteralLoc, StringRef Str);
bool checkMSInheritanceAttrOnDefinition(
    CXXRecordDecl *RD, SourceRange Range, bool BestCase,
    MSInheritanceAttr::Spelling SemanticSpelling);

void CheckAlignasUnderalignment(Decl *D);

/// Adjust the calling convention of a method to be the ABI default if it
/// wasn't specified explicitly.  This handles method types formed from
/// function type typedefs and typename template arguments.
void adjustMemberFunctionCC(QualType &T, bool IsStatic, bool IsCtorOrDtor,
                            SourceLocation Loc);

// Check if there is an explicit attribute, but only look through parens.
// The intent is to look for an attribute on the current declarator, but not
// one that came from a typedef.
bool hasExplicitCallingConv(QualType T);

/// Get the outermost AttributedType node that sets a calling convention.
/// Valid types should not have multiple attributes with different CCs.
const AttributedType *getCallingConvAttributedType(QualType T) const;

/// Stmt attributes - this routine is the top level dispatcher.
StmtResult ProcessStmtAttributes(Stmt *Stmt,
                                 const ParsedAttributesView &Attrs,
                                 SourceRange Range);

void WarnConflictingTypedMethods(ObjCMethodDecl *Method,
                                 ObjCMethodDecl *MethodDecl,
                                 bool IsProtocolMethodDecl);

void CheckConflictingOverridingMethod(ObjCMethodDecl *Method,
                                 ObjCMethodDecl *Overridden,
                                 bool IsProtocolMethodDecl);

/// WarnExactTypedMethods - This routine issues a warning if method
/// implementation declaration matches exactly that of its declaration.
void WarnExactTypedMethods(ObjCMethodDecl *Method,
                           ObjCMethodDecl *MethodDecl,
                           bool IsProtocolMethodDecl);

typedef llvm::SmallPtrSet<Selector, 8> SelectorSet;

/// CheckImplementationIvars - This routine checks if the instance variables
/// listed in the implelementation match those listed in the interface.
void CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
                              ObjCIvarDecl **Fields, unsigned nIvars,
                              SourceLocation Loc);

/// ImplMethodsVsClassMethods - This is main routine to warn if any method
/// remains unimplemented in the class or category \@implementation.
void ImplMethodsVsClassMethods(Scope *S, ObjCImplDecl* IMPDecl,
                               ObjCContainerDecl* IDecl,
                               bool IncompleteImpl = false);

/// DiagnoseUnimplementedProperties - This routine warns on those properties
/// which must be implemented by this implementation.
void DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
                                     ObjCContainerDecl *CDecl,
                                     bool SynthesizeProperties);

/// Diagnose any null-resettable synthesized setters.
void diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl);

/// DefaultSynthesizeProperties - This routine default synthesizes all
/// properties which must be synthesized in the class's \@implementation.
void DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
                                 ObjCInterfaceDecl *IDecl,
                                 SourceLocation AtEnd);
void DefaultSynthesizeProperties(Scope *S, Decl *D, SourceLocation AtEnd);

/// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
/// an ivar synthesized for 'Method' and 'Method' is a property accessor
/// declared in class 'IFace'.
bool IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
                                    ObjCMethodDecl *Method, ObjCIvarDecl *IV);

/// DiagnoseUnusedBackingIvarInAccessor - Issue an 'unused' warning if ivar which
/// backs the property is not used in the property's accessor.
void DiagnoseUnusedBackingIvarInAccessor(Scope *S,
                                         const ObjCImplementationDecl *ImplD);

/// GetIvarBackingPropertyAccessor - If method is a property setter/getter and
/// it property has a backing ivar, returns this ivar; otherwise, returns NULL.
/// It also returns ivar's property on success.
ObjCIvarDecl *GetIvarBackingPropertyAccessor(const ObjCMethodDecl *Method,
                                             const ObjCPropertyDecl *&PDecl) const;

/// Called by ActOnProperty to handle \@property declarations in
/// class extensions.
ObjCPropertyDecl *HandlePropertyInClassExtension(Scope *S,
                    SourceLocation AtLoc,
                    SourceLocation LParenLoc,
                    FieldDeclarator &FD,
                    Selector GetterSel,
                    SourceLocation GetterNameLoc,
                    Selector SetterSel,
                    SourceLocation SetterNameLoc,
                    const bool isReadWrite,
                    unsigned &Attributes,
                    const unsigned AttributesAsWritten,
                    QualType T,
                    TypeSourceInfo *TSI,
                    tok::ObjCKeywordKind MethodImplKind);

/// Called by ActOnProperty and HandlePropertyInClassExtension to
/// handle creating the ObjcPropertyDecl for a category or \@interface.
ObjCPropertyDecl *CreatePropertyDecl(Scope *S,
                                     ObjCContainerDecl *CDecl,
                                     SourceLocation AtLoc,
                                     SourceLocation LParenLoc,
                                     FieldDeclarator &FD,
                                     Selector GetterSel,
                                     SourceLocation GetterNameLoc,
                                     Selector SetterSel,
                                     SourceLocation SetterNameLoc,
                                     const bool isReadWrite,
                                     const unsigned Attributes,
                                     const unsigned AttributesAsWritten,
                                     QualType T,
                                     TypeSourceInfo *TSI,
                                     tok::ObjCKeywordKind MethodImplKind,
                                     DeclContext *lexicalDC = nullptr);

/// AtomicPropertySetterGetterRules - This routine enforces the rule (via
/// warning) when atomic property has one but not the other user-declared
/// setter or getter.
void AtomicPropertySetterGetterRules(ObjCImplDecl* IMPDecl,
                                     ObjCInterfaceDecl* IDecl);

void DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D);

void DiagnoseMissingDesignatedInitOverrides(
                                        const ObjCImplementationDecl *ImplD,
                                        const ObjCInterfaceDecl *IFD);

void DiagnoseDuplicateIvars(ObjCInterfaceDecl *ID, ObjCInterfaceDecl *SID);

enum MethodMatchStrategy {
  MMS_loose,
  MMS_strict
};

/// MatchTwoMethodDeclarations - Checks if two methods' type match and returns
/// true, or false, accordingly.
bool MatchTwoMethodDeclarations(const ObjCMethodDecl *Method,
                                const ObjCMethodDecl *PrevMethod,
                                MethodMatchStrategy strategy = MMS_strict);

/// MatchAllMethodDeclarations - Check methods declaraed in interface or
/// or protocol against those declared in their implementations.
void MatchAllMethodDeclarations(const SelectorSet &InsMap,
                                const SelectorSet &ClsMap,
                                SelectorSet &InsMapSeen,
                                SelectorSet &ClsMapSeen,
                                ObjCImplDecl* IMPDecl,
                                ObjCContainerDecl* IDecl,
                                bool &IncompleteImpl,
                                bool ImmediateClass,
                                bool WarnCategoryMethodImpl=false);

/// CheckCategoryVsClassMethodMatches - Checks that methods implemented in
/// category matches with those implemented in its primary class and
/// warns each time an exact match is found.
void CheckCategoryVsClassMethodMatches(ObjCCategoryImplDecl *CatIMP);

/// Add the given method to the list of globally-known methods.
void addMethodToGlobalList(ObjCMethodList *List, ObjCMethodDecl *Method);

3831private:
/// AddMethodToGlobalPool - Add an instance or factory method to the global
/// pool. See descriptoin of AddInstanceMethodToGlobalPool.
void AddMethodToGlobalPool(ObjCMethodDecl *Method, bool impl, bool instance);

/// LookupMethodInGlobalPool - Returns the instance or factory method and
/// optionally warns if there are multiple signatures.
ObjCMethodDecl *LookupMethodInGlobalPool(Selector Sel, SourceRange R,
                                         bool receiverIdOrClass,
                                         bool instance);

3842public:
/// - Returns instance or factory methods in global method pool for
/// given selector. It checks the desired kind first, if none is found, and
/// parameter checkTheOther is set, it then checks the other kind. If no such
/// method or only one method is found, function returns false; otherwise, it
/// returns true.
bool
CollectMultipleMethodsInGlobalPool(Selector Sel,
                                   SmallVectorImpl<ObjCMethodDecl*>& Methods,
                                   bool InstanceFirst, bool CheckTheOther,
                                   const ObjCObjectType *TypeBound = nullptr);

bool
AreMultipleMethodsInGlobalPool(Selector Sel, ObjCMethodDecl *BestMethod,
                               SourceRange R, bool receiverIdOrClass,
                               SmallVectorImpl<ObjCMethodDecl*>& Methods);

void
DiagnoseMultipleMethodInGlobalPool(SmallVectorImpl<ObjCMethodDecl*> &Methods,
                                   Selector Sel, SourceRange R,
                                   bool receiverIdOrClass);

3864private:
/// - Returns a selector which best matches given argument list or
/// nullptr if none could be found
ObjCMethodDecl *SelectBestMethod(Selector Sel, MultiExprArg Args,
                                 bool IsInstance,
                                 SmallVectorImpl<ObjCMethodDecl*>& Methods);


/// Record the typo correction failure and return an empty correction.
TypoCorrection FailedCorrection(IdentifierInfo *Typo, SourceLocation TypoLoc,
                                bool RecordFailure = true) {
  if (RecordFailure)
    TypoCorrectionFailures[Typo].insert(TypoLoc);
  return TypoCorrection();
}

3880public:
/// AddInstanceMethodToGlobalPool - All instance methods in a translation
/// unit are added to a global pool. This allows us to efficiently associate
/// a selector with a method declaraation for purposes of typechecking
/// messages sent to "id" (where the class of the object is unknown).
void AddInstanceMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
  AddMethodToGlobalPool(Method, impl, /*instance*/true);
}

/// AddFactoryMethodToGlobalPool - Same as above, but for factory methods.
void AddFactoryMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
  AddMethodToGlobalPool(Method, impl, /*instance*/false);
}

/// AddAnyMethodToGlobalPool - Add any method, instance or factory to global
/// pool.
void AddAnyMethodToGlobalPool(Decl *D);

/// LookupInstanceMethodInGlobalPool - Returns the method and warns if
/// there are multiple signatures.
ObjCMethodDecl *LookupInstanceMethodInGlobalPool(Selector Sel, SourceRange R,
                                                 bool receiverIdOrClass=false) {
  return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                  /*instance*/true);
}

/// LookupFactoryMethodInGlobalPool - Returns the method and warns if
/// there are multiple signatures.
ObjCMethodDecl *LookupFactoryMethodInGlobalPool(Selector Sel, SourceRange R,
                                                bool receiverIdOrClass=false) {
  return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                  /*instance*/false);
}

const ObjCMethodDecl *SelectorsForTypoCorrection(Selector Sel,
                            QualType ObjectType=QualType());
/// LookupImplementedMethodInGlobalPool - Returns the method which has an
/// implementation.
ObjCMethodDecl *LookupImplementedMethodInGlobalPool(Selector Sel);

/// CollectIvarsToConstructOrDestruct - Collect those ivars which require
/// initialization.
void CollectIvarsToConstructOrDestruct(ObjCInterfaceDecl *OI,
                                SmallVectorImpl<ObjCIvarDecl*> &Ivars);

//===--------------------------------------------------------------------===//
// Statement Parsing Callbacks: SemaStmt.cpp.
3927public:
class FullExprArg {
public:
  FullExprArg() : E(nullptr) { }
  FullExprArg(Sema &actions) : E(nullptr) { }

  ExprResult release() {
    return E;
  }

  Expr *get() const { return E; }

  Expr *operator->() {
    return E;
  }

private:
  // FIXME: No need to make the entire Sema class a friend when it's just
  // Sema::MakeFullExpr that needs access to the constructor below.
  friend class Sema;

  explicit FullExprArg(Expr *expr) : E(expr) {}

  Expr *E;
};

FullExprArg MakeFullExpr(Expr *Arg) {
  return MakeFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation());
}
FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
  return FullExprArg(
      ActOnFinishFullExpr(Arg, CC, /*DiscardedValue*/ false).get());
}
FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
  ExprResult FE =
      ActOnFinishFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation(),
                          /*DiscardedValue*/ true);
  return FullExprArg(FE.get());
}

StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
StmtResult ActOnExprStmtError();

StmtResult ActOnNullStmt(SourceLocation SemiLoc,
                         bool HasLeadingEmptyMacro = false);

void ActOnStartOfCompoundStmt(bool IsStmtExpr);
void ActOnFinishOfCompoundStmt();
StmtResult ActOnCompoundStmt(SourceLocation L, SourceLocation R,
                             ArrayRef<Stmt *> Elts, bool isStmtExpr);

/// A RAII object to enter scope of a compound statement.
class CompoundScopeRAII {
public:
  CompoundScopeRAII(Sema &S, bool IsStmtExpr = false) : S(S) {
    S.ActOnStartOfCompoundStmt(IsStmtExpr);
  }

  ~CompoundScopeRAII() {
    S.ActOnFinishOfCompoundStmt();
  }

private:
  Sema &S;
};

/// An RAII helper that pops function a function scope on exit.
struct FunctionScopeRAII {
  Sema &S;
  bool Active;
  FunctionScopeRAII(Sema &S) : S(S), Active(true) {}
  ~FunctionScopeRAII() {
    if (Active)
      S.PopFunctionScopeInfo();
  }
  void disable() { Active = false; }
};

StmtResult ActOnDeclStmt(DeclGroupPtrTy Decl,
                                 SourceLocation StartLoc,
                                 SourceLocation EndLoc);
void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);
StmtResult ActOnForEachLValueExpr(Expr *E);
ExprResult ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val);
StmtResult ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHS,
                         SourceLocation DotDotDotLoc, ExprResult RHS,
                         SourceLocation ColonLoc);
void ActOnCaseStmtBody(Stmt *CaseStmt, Stmt *SubStmt);

StmtResult ActOnDefaultStmt(SourceLocation DefaultLoc,
                                    SourceLocation ColonLoc,
                                    Stmt *SubStmt, Scope *CurScope);
StmtResult ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
                          SourceLocation ColonLoc, Stmt *SubStmt);

StmtResult ActOnAttributedStmt(SourceLocation AttrLoc,
                               ArrayRef<const Attr*> Attrs,
                               Stmt *SubStmt);

class ConditionResult;
StmtResult ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                       Stmt *InitStmt,
                       ConditionResult Cond, Stmt *ThenVal,
                       SourceLocation ElseLoc, Stmt *ElseVal);
StmtResult BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                       Stmt *InitStmt,
                       ConditionResult Cond, Stmt *ThenVal,
                       SourceLocation ElseLoc, Stmt *ElseVal);
StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
                                  Stmt *InitStmt,
                                  ConditionResult Cond);
StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
                                         Stmt *Switch, Stmt *Body);
StmtResult ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
                          Stmt *Body);
StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
                       SourceLocation WhileLoc, SourceLocation CondLParen,
                       Expr *Cond, SourceLocation CondRParen);

StmtResult ActOnForStmt(SourceLocation ForLoc,
                        SourceLocation LParenLoc,
                        Stmt *First,
                        ConditionResult Second,
                        FullExprArg Third,
                        SourceLocation RParenLoc,
                        Stmt *Body);
ExprResult CheckObjCForCollectionOperand(SourceLocation forLoc,
                                         Expr *collection);
StmtResult ActOnObjCForCollectionStmt(SourceLocation ForColLoc,
                                      Stmt *First, Expr *collection,
                                      SourceLocation RParenLoc);
StmtResult FinishObjCForCollectionStmt(Stmt *ForCollection, Stmt *Body);

enum BuildForRangeKind {
  /// Initial building of a for-range statement.
  BFRK_Build,
  /// Instantiation or recovery rebuild of a for-range statement. Don't
  /// attempt any typo-correction.
  BFRK_Rebuild,
  /// Determining whether a for-range statement could be built. Avoid any
  /// unnecessary or irreversible actions.
  BFRK_Check
};

StmtResult ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
                                SourceLocation CoawaitLoc,
                                Stmt *InitStmt,
                                Stmt *LoopVar,
                                SourceLocation ColonLoc, Expr *Collection,
                                SourceLocation RParenLoc,
                                BuildForRangeKind Kind);
StmtResult BuildCXXForRangeStmt(SourceLocation ForLoc,
                                SourceLocation CoawaitLoc,
                                Stmt *InitStmt,
                                SourceLocation ColonLoc,
                                Stmt *RangeDecl, Stmt *Begin, Stmt *End,
                                Expr *Cond, Expr *Inc,
                                Stmt *LoopVarDecl,
                                SourceLocation RParenLoc,
                                BuildForRangeKind Kind);
StmtResult FinishCXXForRangeStmt(Stmt *ForRange, Stmt *Body);

StmtResult ActOnGotoStmt(SourceLocation GotoLoc,
                         SourceLocation LabelLoc,
                         LabelDecl *TheDecl);
StmtResult ActOnIndirectGotoStmt(SourceLocation GotoLoc,
                                 SourceLocation StarLoc,
                                 Expr *DestExp);
StmtResult ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope);
StmtResult ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope);

void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                              CapturedRegionKind Kind, unsigned NumParams);
typedef std::pair<StringRef, QualType> CapturedParamNameType;
void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                              CapturedRegionKind Kind,
                              ArrayRef<CapturedParamNameType> Params,
                              unsigned OpenMPCaptureLevel = 0);
StmtResult ActOnCapturedRegionEnd(Stmt *S);
void ActOnCapturedRegionError();
RecordDecl *CreateCapturedStmtRecordDecl(CapturedDecl *&CD,
                                         SourceLocation Loc,
                                         unsigned NumParams);

enum CopyElisionSemanticsKind {
  CES_Strict = 0,
  CES_AllowParameters = 1,
  CES_AllowDifferentTypes = 2,
  CES_AllowExceptionVariables = 4,
  CES_FormerDefault = (CES_AllowParameters),
  CES_Default = (CES_AllowParameters | CES_AllowDifferentTypes),
  CES_AsIfByStdMove = (CES_AllowParameters | CES_AllowDifferentTypes |
                       CES_AllowExceptionVariables),
};

VarDecl *getCopyElisionCandidate(QualType ReturnType, Expr *E,
                                 CopyElisionSemanticsKind CESK);
bool isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
                            CopyElisionSemanticsKind CESK);

StmtResult ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                           Scope *CurScope);
StmtResult BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp);
StmtResult ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp);

StmtResult ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
                           bool IsVolatile, unsigned NumOutputs,
                           unsigned NumInputs, IdentifierInfo **Names,
                           MultiExprArg Constraints, MultiExprArg Exprs,
                           Expr *AsmString, MultiExprArg Clobbers,
                           unsigned NumLabels,
                           SourceLocation RParenLoc);

void FillInlineAsmIdentifierInfo(Expr *Res,
                                 llvm::InlineAsmIdentifierInfo &Info);
ExprResult LookupInlineAsmIdentifier(CXXScopeSpec &SS,
                                     SourceLocation TemplateKWLoc,
                                     UnqualifiedId &Id,
                                     bool IsUnevaluatedContext);
bool LookupInlineAsmField(StringRef Base, StringRef Member,
                          unsigned &Offset, SourceLocation AsmLoc);
ExprResult LookupInlineAsmVarDeclField(Expr *RefExpr, StringRef Member,
                                       SourceLocation AsmLoc);
StmtResult ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
                          ArrayRef<Token> AsmToks,
                          StringRef AsmString,
                          unsigned NumOutputs, unsigned NumInputs,
                          ArrayRef<StringRef> Constraints,
                          ArrayRef<StringRef> Clobbers,
                          ArrayRef<Expr*> Exprs,
                          SourceLocation EndLoc);
LabelDecl *GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
                                 SourceLocation Location,
                                 bool AlwaysCreate);

VarDecl *BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType ExceptionType,
                                SourceLocation StartLoc,
                                SourceLocation IdLoc, IdentifierInfo *Id,
                                bool Invalid = false);

Decl *ActOnObjCExceptionDecl(Scope *S, Declarator &D);

StmtResult ActOnObjCAtCatchStmt(SourceLocation AtLoc, SourceLocation RParen,
                                Decl *Parm, Stmt *Body);

StmtResult ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body);

StmtResult ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
                              MultiStmtArg Catch, Stmt *Finally);

StmtResult BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw);
StmtResult ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
                                Scope *CurScope);
ExprResult ActOnObjCAtSynchronizedOperand(SourceLocation atLoc,
                                          Expr *operand);
StmtResult ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc,
                                       Expr *SynchExpr,
                                       Stmt *SynchBody);

StmtResult ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body);

VarDecl *BuildExceptionDeclaration(Scope *S, TypeSourceInfo *TInfo,
                                   SourceLocation StartLoc,
                                   SourceLocation IdLoc,
                                   IdentifierInfo *Id);

Decl *ActOnExceptionDeclarator(Scope *S, Declarator &D);

StmtResult ActOnCXXCatchBlock(SourceLocation CatchLoc,
                              Decl *ExDecl, Stmt *HandlerBlock);
StmtResult ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
                            ArrayRef<Stmt *> Handlers);

StmtResult ActOnSEHTryBlock(bool IsCXXTry, // try (true) or __try (false) ?
                            SourceLocation TryLoc, Stmt *TryBlock,
                            Stmt *Handler);
StmtResult ActOnSEHExceptBlock(SourceLocation Loc,
                               Expr *FilterExpr,
                               Stmt *Block);
void ActOnStartSEHFinallyBlock();
void ActOnAbortSEHFinallyBlock();
StmtResult ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block);
StmtResult ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope);

void DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock);

bool ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const;

/// If it's a file scoped decl that must warn if not used, keep track
/// of it.
void MarkUnusedFileScopedDecl(const DeclaratorDecl *D);

/// DiagnoseUnusedExprResult - If the statement passed in is an expression
/// whose result is unused, warn.
void DiagnoseUnusedExprResult(const Stmt *S);
void DiagnoseUnusedNestedTypedefs(const RecordDecl *D);
void DiagnoseUnusedDecl(const NamedDecl *ND);

/// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
/// statement as a \p Body, and it is located on the same line.
///
/// This helps prevent bugs due to typos, such as:
///     if (condition);
///       do_stuff();
void DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
                           const Stmt *Body,
                           unsigned DiagID);

/// Warn if a for/while loop statement \p S, which is followed by
/// \p PossibleBody, has a suspicious null statement as a body.
void DiagnoseEmptyLoopBody(const Stmt *S,
                           const Stmt *PossibleBody);

/// Warn if a value is moved to itself.
void DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr,
                      SourceLocation OpLoc);

/// Warn if we're implicitly casting from a _Nullable pointer type to a
/// _Nonnull one.
void diagnoseNullableToNonnullConversion(QualType DstType, QualType SrcType,
                                         SourceLocation Loc);

/// Warn when implicitly casting 0 to nullptr.
void diagnoseZeroToNullptrConversion(CastKind Kind, const Expr *E);

ParsingDeclState PushParsingDeclaration(sema::DelayedDiagnosticPool &pool) {
  return DelayedDiagnostics.push(pool);
}
void PopParsingDeclaration(ParsingDeclState state, Decl *decl);

typedef ProcessingContextState ParsingClassState;
ParsingClassState PushParsingClass() {
  return DelayedDiagnostics.pushUndelayed();
}
void PopParsingClass(ParsingClassState state) {
  DelayedDiagnostics.popUndelayed(state);
}

void redelayDiagnostics(sema::DelayedDiagnosticPool &pool);

void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
                                const ObjCInterfaceDecl *UnknownObjCClass,
                                bool ObjCPropertyAccess,
                                bool AvoidPartialAvailabilityChecks = false,
                                ObjCInterfaceDecl *ClassReceiver = nullptr);

bool makeUnavailableInSystemHeader(SourceLocation loc,
                                   UnavailableAttr::ImplicitReason reason);

/// Issue any -Wunguarded-availability warnings in \c FD
void DiagnoseUnguardedAvailabilityViolations(Decl *FD);

//===--------------------------------------------------------------------===//
// Expression Parsing Callbacks: SemaExpr.cpp.

bool CanUseDecl(NamedDecl *D, bool TreatUnavailableAsInvalid);
bool DiagnoseUseOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
                       const ObjCInterfaceDecl *UnknownObjCClass = nullptr,
                       bool ObjCPropertyAccess = false,
                       bool AvoidPartialAvailabilityChecks = false,
                       ObjCInterfaceDecl *ClassReciever = nullptr);
void NoteDeletedFunction(FunctionDecl *FD);
void NoteDeletedInheritingConstructor(CXXConstructorDecl *CD);
bool DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *PD,
                                      ObjCMethodDecl *Getter,
                                      SourceLocation Loc);
void DiagnoseSentinelCalls(NamedDecl *D, SourceLocation Loc,
                           ArrayRef<Expr *> Args);

void PushExpressionEvaluationContext(
    ExpressionEvaluationContext NewContext, Decl *LambdaContextDecl = nullptr,
    ExpressionEvaluationContextRecord::ExpressionKind Type =
        ExpressionEvaluationContextRecord::EK_Other);
enum ReuseLambdaContextDecl_t { ReuseLambdaContextDecl };
void PushExpressionEvaluationContext(
    ExpressionEvaluationContext NewContext, ReuseLambdaContextDecl_t,
    ExpressionEvaluationContextRecord::ExpressionKind Type =
        ExpressionEvaluationContextRecord::EK_Other);
void PopExpressionEvaluationContext();

void DiscardCleanupsInEvaluationContext();

ExprResult TransformToPotentiallyEvaluated(Expr *E);
ExprResult HandleExprEvaluationContextForTypeof(Expr *E);

ExprResult CheckUnevaluatedOperand(Expr *E);
void CheckUnusedVolatileAssignment(Expr *E);

ExprResult ActOnConstantExpression(ExprResult Res);

// Functions for marking a declaration referenced.  These functions also
// contain the relevant logic for marking if a reference to a function or
// variable is an odr-use (in the C++11 sense).  There are separate variants
// for expressions referring to a decl; these exist because odr-use marking
// needs to be delayed for some constant variables when we build one of the
// named expressions.
//
// MightBeOdrUse indicates whether the use could possibly be an odr-use, and
// should usually be true. This only needs to be set to false if the lack of
// odr-use cannot be determined from the current context (for instance,
// because the name denotes a virtual function and was written without an
// explicit nested-name-specifier).
void MarkAnyDeclReferenced(SourceLocation Loc, Decl *D, bool MightBeOdrUse);
void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
                            bool MightBeOdrUse = true);
void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
void MarkDeclRefReferenced(DeclRefExpr *E, const Expr *Base = nullptr);
void MarkMemberReferenced(MemberExpr *E);
void MarkFunctionParmPackReferenced(FunctionParmPackExpr *E);
void MarkCaptureUsedInEnclosingContext(VarDecl *Capture, SourceLocation Loc,
                                       unsigned CapturingScopeIndex);

ExprResult CheckLValueToRValueConversionOperand(Expr *E);
void CleanupVarDeclMarking();

enum TryCaptureKind {
  TryCapture_Implicit, TryCapture_ExplicitByVal, TryCapture_ExplicitByRef
};

/// Try to capture the given variable.
///
/// \param Var The variable to capture.
///
/// \param Loc The location at which the capture occurs.
///
/// \param Kind The kind of capture, which may be implicit (for either a
/// block or a lambda), or explicit by-value or by-reference (for a lambda).
///
/// \param EllipsisLoc The location of the ellipsis, if one is provided in
/// an explicit lambda capture.
///
/// \param BuildAndDiagnose Whether we are actually supposed to add the
/// captures or diagnose errors. If false, this routine merely check whether
/// the capture can occur without performing the capture itself or complaining
/// if the variable cannot be captured.
///
/// \param CaptureType Will be set to the type of the field used to capture
/// this variable in the innermost block or lambda. Only valid when the
/// variable can be captured.
///
/// \param DeclRefType Will be set to the type of a reference to the capture
/// from within the current scope. Only valid when the variable can be
/// captured.
///
/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
/// This is useful when enclosing lambdas must speculatively capture
/// variables that may or may not be used in certain specializations of
/// a nested generic lambda.
///
/// \returns true if an error occurred (i.e., the variable cannot be
/// captured) and false if the capture succeeded.
bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc, TryCaptureKind Kind,
                        SourceLocation EllipsisLoc, bool BuildAndDiagnose,
                        QualType &CaptureType,
                        QualType &DeclRefType,
                        const unsigned *const FunctionScopeIndexToStopAt);

/// Try to capture the given variable.
bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc,
                        TryCaptureKind Kind = TryCapture_Implicit,
                        SourceLocation EllipsisLoc = SourceLocation());

/// Checks if the variable must be captured.
bool NeedToCaptureVariable(VarDecl *Var, SourceLocation Loc);

/// Given a variable, determine the type that a reference to that
/// variable will have in the given scope.
QualType getCapturedDeclRefType(VarDecl *Var, SourceLocation Loc);

/// Mark all of the declarations referenced within a particular AST node as
/// referenced. Used when template instantiation instantiates a non-dependent
/// type -- entities referenced by the type are now referenced.
void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
void MarkDeclarationsReferencedInExpr(Expr *E,
                                      bool SkipLocalVariables = false);

/// Try to recover by turning the given expression into a
/// call.  Returns true if recovery was attempted or an error was
/// emitted; this may also leave the ExprResult invalid.
bool tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
                          bool ForceComplain = false,
                          bool (*IsPlausibleResult)(QualType) = nullptr);

/// Figure out if an expression could be turned into a call.
bool tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
                   UnresolvedSetImpl &NonTemplateOverloads);

/// Conditionally issue a diagnostic based on the current
/// evaluation context.
///
/// \param Statement If Statement is non-null, delay reporting the
/// diagnostic until the function body is parsed, and then do a basic
/// reachability analysis to determine if the statement is reachable.
/// If it is unreachable, the diagnostic will not be emitted.
bool DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
                         const PartialDiagnostic &PD);
/// Similar, but diagnostic is only produced if all the specified statements
/// are reachable.
bool DiagRuntimeBehavior(SourceLocation Loc, ArrayRef<const Stmt*> Stmts,
                         const PartialDiagnostic &PD);

// Primary Expressions.
SourceRange getExprRange(Expr *E) const;

ExprResult ActOnIdExpression(
    Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    UnqualifiedId &Id, bool HasTrailingLParen, bool IsAddressOfOperand,
    CorrectionCandidateCallback *CCC = nullptr,
    bool IsInlineAsmIdentifier = false, Token *KeywordReplacement = nullptr);

void DecomposeUnqualifiedId(const UnqualifiedId &Id,
                            TemplateArgumentListInfo &Buffer,
                            DeclarationNameInfo &NameInfo,
                            const TemplateArgumentListInfo *&TemplateArgs);

bool
DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
                    CorrectionCandidateCallback &CCC,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr,
                    ArrayRef<Expr *> Args = None, TypoExpr **Out = nullptr);

DeclResult LookupIvarInObjCMethod(LookupResult &Lookup, Scope *S,
                                  IdentifierInfo *II);
ExprResult BuildIvarRefExpr(Scope *S, SourceLocation Loc, ObjCIvarDecl *IV);

ExprResult LookupInObjCMethod(LookupResult &LookUp, Scope *S,
                              IdentifierInfo *II,
                              bool AllowBuiltinCreation=false);

ExprResult ActOnDependentIdExpression(const CXXScopeSpec &SS,
                                      SourceLocation TemplateKWLoc,
                                      const DeclarationNameInfo &NameInfo,
                                      bool isAddressOfOperand,
                              const TemplateArgumentListInfo *TemplateArgs);

/// If \p D cannot be odr-used in the current expression evaluation context,
/// return a reason explaining why. Otherwise, return NOUR_None.
NonOdrUseReason getNonOdrUseReasonInCurrentContext(ValueDecl *D);

DeclRefExpr *BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                              SourceLocation Loc,
                              const CXXScopeSpec *SS = nullptr);
DeclRefExpr *
BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                 const DeclarationNameInfo &NameInfo,
                 const CXXScopeSpec *SS = nullptr,
                 NamedDecl *FoundD = nullptr,
                 SourceLocation TemplateKWLoc = SourceLocation(),
                 const TemplateArgumentListInfo *TemplateArgs = nullptr);
DeclRefExpr *
BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
                 const DeclarationNameInfo &NameInfo,
                 NestedNameSpecifierLoc NNS,
                 NamedDecl *FoundD = nullptr,
                 SourceLocation TemplateKWLoc = SourceLocation(),
                 const TemplateArgumentListInfo *TemplateArgs = nullptr);

ExprResult
BuildAnonymousStructUnionMemberReference(
    const CXXScopeSpec &SS,
    SourceLocation nameLoc,
    IndirectFieldDecl *indirectField,
    DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_none),
    Expr *baseObjectExpr = nullptr,
    SourceLocation opLoc = SourceLocation());

ExprResult BuildPossibleImplicitMemberExpr(const CXXScopeSpec &SS,
                                           SourceLocation TemplateKWLoc,
                                           LookupResult &R,
                              const TemplateArgumentListInfo *TemplateArgs,
                                           const Scope *S);
ExprResult BuildImplicitMemberExpr(const CXXScopeSpec &SS,
                                   SourceLocation TemplateKWLoc,
                                   LookupResult &R,
                              const TemplateArgumentListInfo *TemplateArgs,
                                   bool IsDefiniteInstance,
                                   const Scope *S);
bool UseArgumentDependentLookup(const CXXScopeSpec &SS,
                                const LookupResult &R,
                                bool HasTrailingLParen);

ExprResult
BuildQualifiedDeclarationNameExpr(CXXScopeSpec &SS,
                                  const DeclarationNameInfo &NameInfo,
                                  bool IsAddressOfOperand, const Scope *S,
                                  TypeSourceInfo **RecoveryTSI = nullptr);

ExprResult BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
                                     SourceLocation TemplateKWLoc,
                              const DeclarationNameInfo &NameInfo,
                              const TemplateArgumentListInfo *TemplateArgs);

ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS,
                                    LookupResult &R,
                                    bool NeedsADL,
                                    bool AcceptInvalidDecl = false);
ExprResult BuildDeclarationNameExpr(
    const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo, NamedDecl *D,
    NamedDecl *FoundD = nullptr,
    const TemplateArgumentListInfo *TemplateArgs = nullptr,
    bool AcceptInvalidDecl = false);

ExprResult BuildLiteralOperatorCall(LookupResult &R,
                    DeclarationNameInfo &SuffixInfo,
                    ArrayRef<Expr *> Args,
                    SourceLocation LitEndLoc,
                    TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr);

ExprResult BuildPredefinedExpr(SourceLocation Loc,
                               PredefinedExpr::IdentKind IK);
ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
ExprResult ActOnIntegerConstant(SourceLocation Loc, uint64_t Val);

bool CheckLoopHintExpr(Expr *E, SourceLocation Loc);

ExprResult ActOnNumericConstant(const Token &Tok, Scope *UDLScope = nullptr);
ExprResult ActOnCharacterConstant(const Token &Tok,
                                  Scope *UDLScope = nullptr);
ExprResult ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E);
ExprResult ActOnParenListExpr(SourceLocation L,
                              SourceLocation R,
                              MultiExprArg Val);

/// ActOnStringLiteral - The specified tokens were lexed as pasted string
/// fragments (e.g. "foo" "bar" L"baz").
ExprResult ActOnStringLiteral(ArrayRef<Token> StringToks,
                              Scope *UDLScope = nullptr);

ExprResult ActOnGenericSelectionExpr(SourceLocation KeyLoc,
                                     SourceLocation DefaultLoc,
                                     SourceLocation RParenLoc,
                                     Expr *ControllingExpr,
                                     ArrayRef<ParsedType> ArgTypes,
                                     ArrayRef<Expr *> ArgExprs);
ExprResult CreateGenericSelectionExpr(SourceLocation KeyLoc,
                                      SourceLocation DefaultLoc,
                                      SourceLocation RParenLoc,
                                      Expr *ControllingExpr,
                                      ArrayRef<TypeSourceInfo *> Types,
                                      ArrayRef<Expr *> Exprs);

// Binary/Unary Operators.  'Tok' is the token for the operator.
ExprResult CreateBuiltinUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
                                Expr *InputExpr);
ExprResult BuildUnaryOp(Scope *S, SourceLocation OpLoc,
                        UnaryOperatorKind Opc, Expr *Input);
ExprResult ActOnUnaryOp(Scope *S, SourceLocation OpLoc,
                        tok::TokenKind Op, Expr *Input);

bool isQualifiedMemberAccess(Expr *E);
QualType CheckAddressOfOperand(ExprResult &Operand, SourceLocation OpLoc);

ExprResult CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
                                          SourceLocation OpLoc,
                                          UnaryExprOrTypeTrait ExprKind,
                                          SourceRange R);
ExprResult CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
                                          UnaryExprOrTypeTrait ExprKind);
ExprResult
  ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
                                UnaryExprOrTypeTrait ExprKind,
                                bool IsType, void *TyOrEx,
                                SourceRange ArgRange);

ExprResult CheckPlaceholderExpr(Expr *E);
bool CheckVecStepExpr(Expr *E);

bool CheckUnaryExprOrTypeTraitOperand(Expr *E, UnaryExprOrTypeTrait ExprKind);
bool CheckUnaryExprOrTypeTraitOperand(QualType ExprType, SourceLocation OpLoc,
                                      SourceRange ExprRange,
                                      UnaryExprOrTypeTrait ExprKind);
ExprResult ActOnSizeofParameterPackExpr(Scope *S,
                                        SourceLocation OpLoc,
                                        IdentifierInfo &Name,
                                        SourceLocation NameLoc,
                                        SourceLocation RParenLoc);
ExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
                               tok::TokenKind Kind, Expr *Input);

ExprResult ActOnArraySubscriptExpr(Scope *S, Expr *Base, SourceLocation LLoc,
                                   Expr *Idx, SourceLocation RLoc);
ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
                                           Expr *Idx, SourceLocation RLoc);
ExprResult ActOnOMPArraySectionExpr(Expr *Base, SourceLocation LBLoc,
                                    Expr *LowerBound, SourceLocation ColonLoc,
                                    Expr *Length, SourceLocation RBLoc);

// This struct is for use by ActOnMemberAccess to allow
// BuildMemberReferenceExpr to be able to reinvoke ActOnMemberAccess after
// changing the access operator from a '.' to a '->' (to see if that is the
// change needed to fix an error about an unknown member, e.g. when the class
// defines a custom operator->).
struct ActOnMemberAccessExtraArgs {
  Scope *S;
  UnqualifiedId &Id;
  Decl *ObjCImpDecl;
};

ExprResult BuildMemberReferenceExpr(
    Expr *Base, QualType BaseType, SourceLocation OpLoc, bool IsArrow,
    CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    NamedDecl *FirstQualifierInScope, const DeclarationNameInfo &NameInfo,
    const TemplateArgumentListInfo *TemplateArgs,
    const Scope *S,
    ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);

ExprResult
BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
                         bool IsArrow, const CXXScopeSpec &SS,
                         SourceLocation TemplateKWLoc,
                         NamedDecl *FirstQualifierInScope, LookupResult &R,
                         const TemplateArgumentListInfo *TemplateArgs,
                         const Scope *S,
                         bool SuppressQualifierCheck = false,
                         ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);

ExprResult BuildFieldReferenceExpr(Expr *BaseExpr, bool IsArrow,
                                   SourceLocation OpLoc,
                                   const CXXScopeSpec &SS, FieldDecl *Field,
                                   DeclAccessPair FoundDecl,
                                   const DeclarationNameInfo &MemberNameInfo);

ExprResult PerformMemberExprBaseConversion(Expr *Base, bool IsArrow);

bool CheckQualifiedMemberReference(Expr *BaseExpr, QualType BaseType,
                                   const CXXScopeSpec &SS,
                                   const LookupResult &R);

ExprResult ActOnDependentMemberExpr(Expr *Base, QualType BaseType,
                                    bool IsArrow, SourceLocation OpLoc,
                                    const CXXScopeSpec &SS,
                                    SourceLocation TemplateKWLoc,
                                    NamedDecl *FirstQualifierInScope,
                             const DeclarationNameInfo &NameInfo,
                             const TemplateArgumentListInfo *TemplateArgs);

ExprResult ActOnMemberAccessExpr(Scope *S, Expr *Base,
                                 SourceLocation OpLoc,
                                 tok::TokenKind OpKind,
                                 CXXScopeSpec &SS,
                                 SourceLocation TemplateKWLoc,
                                 UnqualifiedId &Member,
                                 Decl *ObjCImpDecl);

MemberExpr *
BuildMemberExpr(Expr *Base, bool IsArrow, SourceLocation OpLoc,
                const CXXScopeSpec *SS, SourceLocation TemplateKWLoc,
                ValueDecl *Member, DeclAccessPair FoundDecl,
                bool HadMultipleCandidates,
                const DeclarationNameInfo &MemberNameInfo, QualType Ty,
                ExprValueKind VK, ExprObjectKind OK,
                const TemplateArgumentListInfo *TemplateArgs = nullptr);
MemberExpr *
BuildMemberExpr(Expr *Base, bool IsArrow, SourceLocation OpLoc,
                NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
                ValueDecl *Member, DeclAccessPair FoundDecl,
                bool HadMultipleCandidates,
                const DeclarationNameInfo &MemberNameInfo, QualType Ty,
                ExprValueKind VK, ExprObjectKind OK,
                const TemplateArgumentListInfo *TemplateArgs = nullptr);

void ActOnDefaultCtorInitializers(Decl *CDtorDecl);
bool ConvertArgumentsForCall(CallExpr *Call, Expr *Fn,
                             FunctionDecl *FDecl,
                             const FunctionProtoType *Proto,
                             ArrayRef<Expr *> Args,
                             SourceLocation RParenLoc,
                             bool ExecConfig = false);
void CheckStaticArrayArgument(SourceLocation CallLoc,
                              ParmVarDecl *Param,
                              const Expr *ArgExpr);

/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
/// This provides the location of the left/right parens and a list of comma
/// locations.
ExprResult ActOnCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
                         MultiExprArg ArgExprs, SourceLocation RParenLoc,
                         Expr *ExecConfig = nullptr);
ExprResult BuildCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
                         MultiExprArg ArgExprs, SourceLocation RParenLoc,
                         Expr *ExecConfig = nullptr,
                         bool IsExecConfig = false);
enum class AtomicArgumentOrder { API, AST };
ExprResult
BuildAtomicExpr(SourceRange CallRange, SourceRange ExprRange,
                SourceLocation RParenLoc, MultiExprArg Args,
                AtomicExpr::AtomicOp Op,
                AtomicArgumentOrder ArgOrder = AtomicArgumentOrder::API);
ExprResult
BuildResolvedCallExpr(Expr *Fn, NamedDecl *NDecl, SourceLocation LParenLoc,
                      ArrayRef<Expr *> Arg, SourceLocation RParenLoc,
                      Expr *Config = nullptr, bool IsExecConfig = false,
                      ADLCallKind UsesADL = ADLCallKind::NotADL);

ExprResult ActOnCUDAExecConfigExpr(Scope *S, SourceLocation LLLLoc,
                                   MultiExprArg ExecConfig,
                                   SourceLocation GGGLoc);

ExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
                         Declarator &D, ParsedType &Ty,
                         SourceLocation RParenLoc, Expr *CastExpr);
ExprResult BuildCStyleCastExpr(SourceLocation LParenLoc,
                               TypeSourceInfo *Ty,
                               SourceLocation RParenLoc,
                               Expr *Op);
CastKind PrepareScalarCast(ExprResult &src, QualType destType);

/// Build an altivec or OpenCL literal.
ExprResult BuildVectorLiteral(SourceLocation LParenLoc,
                              SourceLocation RParenLoc, Expr *E,
                              TypeSourceInfo *TInfo);

ExprResult MaybeConvertParenListExprToParenExpr(Scope *S, Expr *ME);

ExprResult ActOnCompoundLiteral(SourceLocation LParenLoc,
                                ParsedType Ty,
                                SourceLocation RParenLoc,
                                Expr *InitExpr);

ExprResult BuildCompoundLiteralExpr(SourceLocation LParenLoc,
                                    TypeSourceInfo *TInfo,
                                    SourceLocation RParenLoc,
                                    Expr *LiteralExpr);

ExprResult ActOnInitList(SourceLocation LBraceLoc,
                         MultiExprArg InitArgList,
                         SourceLocation RBraceLoc);

ExprResult BuildInitList(SourceLocation LBraceLoc,
                         MultiExprArg InitArgList,
                         SourceLocation RBraceLoc);

ExprResult ActOnDesignatedInitializer(Designation &Desig,
                                      SourceLocation EqualOrColonLoc,
                                      bool GNUSyntax,
                                      ExprResult Init);

4765private:
static BinaryOperatorKind ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind);

4768public:
ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc,
                      tok::TokenKind Kind, Expr *LHSExpr, Expr *RHSExpr);
ExprResult BuildBinOp(Scope *S, SourceLocation OpLoc,
                      BinaryOperatorKind Opc, Expr *LHSExpr, Expr *RHSExpr);
ExprResult CreateBuiltinBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
                              Expr *LHSExpr, Expr *RHSExpr);

void DiagnoseCommaOperator(const Expr *LHS, SourceLocation Loc);

/// ActOnConditionalOp - Parse a ?: operation.  Note that 'LHS' may be null
/// in the case of a the GNU conditional expr extension.
ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,
                              SourceLocation ColonLoc,
                              Expr *CondExpr, Expr *LHSExpr, Expr *RHSExpr);

/// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
                          LabelDecl *TheDecl);

void ActOnStartStmtExpr();
ExprResult ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
                         SourceLocation RPLoc); // "({..})"
// Handle the final expression in a statement expression.
ExprResult ActOnStmtExprResult(ExprResult E);
void ActOnStmtExprError();

// __builtin_offsetof(type, identifier(.identifier|[expr])*)
struct OffsetOfComponent {
  SourceLocation LocStart, LocEnd;
  bool isBrackets;  // true if [expr], false if .ident
  union {
    IdentifierInfo *IdentInfo;
    Expr *E;
  } U;
};

/// __builtin_offsetof(type, a.b[123][456].c)
ExprResult BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
                                TypeSourceInfo *TInfo,
                                ArrayRef<OffsetOfComponent> Components,
                                SourceLocation RParenLoc);
ExprResult ActOnBuiltinOffsetOf(Scope *S,
                                SourceLocation BuiltinLoc,
                                SourceLocation TypeLoc,
                                ParsedType ParsedArgTy,
                                ArrayRef<OffsetOfComponent> Components,
                                SourceLocation RParenLoc);

// __builtin_choose_expr(constExpr, expr1, expr2)
ExprResult ActOnChooseExpr(SourceLocation BuiltinLoc,
                           Expr *CondExpr, Expr *LHSExpr,
                           Expr *RHSExpr, SourceLocation RPLoc);

// __builtin_va_arg(expr, type)
ExprResult ActOnVAArg(SourceLocation BuiltinLoc, Expr *E, ParsedType Ty,
                      SourceLocation RPLoc);
ExprResult BuildVAArgExpr(SourceLocation BuiltinLoc, Expr *E,
                          TypeSourceInfo *TInfo, SourceLocation RPLoc);

// __builtin_LINE(), __builtin_FUNCTION(), __builtin_FILE(),
// __builtin_COLUMN()
ExprResult ActOnSourceLocExpr(SourceLocExpr::IdentKind Kind,
                              SourceLocation BuiltinLoc,
                              SourceLocation RPLoc);

// Build a potentially resolved SourceLocExpr.
ExprResult BuildSourceLocExpr(SourceLocExpr::IdentKind Kind,
                              SourceLocation BuiltinLoc, SourceLocation RPLoc,
                              DeclContext *ParentContext);

// __null
ExprResult ActOnGNUNullExpr(SourceLocation TokenLoc);

bool CheckCaseExpression(Expr *E);

/// Describes the result of an "if-exists" condition check.
enum IfExistsResult {
  /// The symbol exists.
  IER_Exists,

  /// The symbol does not exist.
  IER_DoesNotExist,

  /// The name is a dependent name, so the results will differ
  /// from one instantiation to the next.
  IER_Dependent,

  /// An error occurred.
  IER_Error
};

IfExistsResult
CheckMicrosoftIfExistsSymbol(Scope *S, CXXScopeSpec &SS,
                             const DeclarationNameInfo &TargetNameInfo);

IfExistsResult
CheckMicrosoftIfExistsSymbol(Scope *S, SourceLocation KeywordLoc,
                             bool IsIfExists, CXXScopeSpec &SS,
                             UnqualifiedId &Name);

StmtResult BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
                                      bool IsIfExists,
                                      NestedNameSpecifierLoc QualifierLoc,
                                      DeclarationNameInfo NameInfo,
                                      Stmt *Nested);
StmtResult ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
                                      bool IsIfExists,
                                      CXXScopeSpec &SS, UnqualifiedId &Name,
                                      Stmt *Nested);

//===------------------------- "Block" Extension ------------------------===//

/// ActOnBlockStart - This callback is invoked when a block literal is
/// started.
void ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope);

/// ActOnBlockArguments - This callback allows processing of block arguments.
/// If there are no arguments, this is still invoked.
void ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
                         Scope *CurScope);

/// ActOnBlockError - If there is an error parsing a block, this callback
/// is invoked to pop the information about the block from the action impl.
void ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope);

/// ActOnBlockStmtExpr - This is called when the body of a block statement
/// literal was successfully completed.  ^(int x){...}
ExprResult ActOnBlockStmtExpr(SourceLocation CaretLoc, Stmt *Body,
                              Scope *CurScope);

//===---------------------------- Clang Extensions ----------------------===//

/// __builtin_convertvector(...)
ExprResult ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
                                  SourceLocation BuiltinLoc,
                                  SourceLocation RParenLoc);

//===---------------------------- OpenCL Features -----------------------===//

/// __builtin_astype(...)
ExprResult ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
                           SourceLocation BuiltinLoc,
                           SourceLocation RParenLoc);

//===---------------------------- C++ Features --------------------------===//

// Act on C++ namespaces
Decl *ActOnStartNamespaceDef(Scope *S, SourceLocation InlineLoc,
                             SourceLocation NamespaceLoc,
                             SourceLocation IdentLoc, IdentifierInfo *Ident,
                             SourceLocation LBrace,
                             const ParsedAttributesView &AttrList,
                             UsingDirectiveDecl *&UsingDecl);
void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);

NamespaceDecl *getStdNamespace() const;
NamespaceDecl *getOrCreateStdNamespace();

NamespaceDecl *lookupStdExperimentalNamespace();

CXXRecordDecl *getStdBadAlloc() const;
EnumDecl *getStdAlignValT() const;

4932private:
// A cache representing if we've fully checked the various comparison category
// types stored in ASTContext. The bit-index corresponds to the integer value
// of a ComparisonCategoryType enumerator.
llvm::SmallBitVector FullyCheckedComparisonCategories;

ValueDecl *tryLookupCtorInitMemberDecl(CXXRecordDecl *ClassDecl,
                                       CXXScopeSpec &SS,
                                       ParsedType TemplateTypeTy,
                                       IdentifierInfo *MemberOrBase);

4943public:
/// Lookup the specified comparison category types in the standard
///   library, an check the VarDecls possibly returned by the operator<=>
///   builtins for that type.
///
/// \return The type of the comparison category type corresponding to the
///   specified Kind, or a null type if an error occurs
QualType CheckComparisonCategoryType(ComparisonCategoryType Kind,
                                     SourceLocation Loc);

/// Tests whether Ty is an instance of std::initializer_list and, if
/// it is and Element is not NULL, assigns the element type to Element.
bool isStdInitializerList(QualType Ty, QualType *Element);

/// Looks for the std::initializer_list template and instantiates it
/// with Element, or emits an error if it's not found.
///
/// \returns The instantiated template, or null on error.
QualType BuildStdInitializerList(QualType Element, SourceLocation Loc);

/// Determine whether Ctor is an initializer-list constructor, as
/// defined in [dcl.init.list]p2.
bool isInitListConstructor(const FunctionDecl *Ctor);

Decl *ActOnUsingDirective(Scope *CurScope, SourceLocation UsingLoc,
                          SourceLocation NamespcLoc, CXXScopeSpec &SS,
                          SourceLocation IdentLoc,
                          IdentifierInfo *NamespcName,
                          const ParsedAttributesView &AttrList);

void PushUsingDirective(Scope *S, UsingDirectiveDecl *UDir);

Decl *ActOnNamespaceAliasDef(Scope *CurScope,
                             SourceLocation NamespaceLoc,
                             SourceLocation AliasLoc,
                             IdentifierInfo *Alias,
                             CXXScopeSpec &SS,
                             SourceLocation IdentLoc,
                             IdentifierInfo *Ident);

void HideUsingShadowDecl(Scope *S, UsingShadowDecl *Shadow);
bool CheckUsingShadowDecl(UsingDecl *UD, NamedDecl *Target,
                          const LookupResult &PreviousDecls,
                          UsingShadowDecl *&PrevShadow);
UsingShadowDecl *BuildUsingShadowDecl(Scope *S, UsingDecl *UD,
                                      NamedDecl *Target,
                                      UsingShadowDecl *PrevDecl);

bool CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
                                 bool HasTypenameKeyword,
                                 const CXXScopeSpec &SS,
                                 SourceLocation NameLoc,
                                 const LookupResult &Previous);
bool CheckUsingDeclQualifier(SourceLocation UsingLoc,
                             bool HasTypename,
                             const CXXScopeSpec &SS,
                             const DeclarationNameInfo &NameInfo,
                             SourceLocation NameLoc);

NamedDecl *BuildUsingDeclaration(
    Scope *S, AccessSpecifier AS, SourceLocation UsingLoc,
    bool HasTypenameKeyword, SourceLocation TypenameLoc, CXXScopeSpec &SS,
    DeclarationNameInfo NameInfo, SourceLocation EllipsisLoc,
    const ParsedAttributesView &AttrList, bool IsInstantiation);
NamedDecl *BuildUsingPackDecl(NamedDecl *InstantiatedFrom,
                              ArrayRef<NamedDecl *> Expansions);

bool CheckInheritingConstructorUsingDecl(UsingDecl *UD);

/// Given a derived-class using shadow declaration for a constructor and the
/// correspnding base class constructor, find or create the implicit
/// synthesized derived class constructor to use for this initialization.
CXXConstructorDecl *
findInheritingConstructor(SourceLocation Loc, CXXConstructorDecl *BaseCtor,
                          ConstructorUsingShadowDecl *DerivedShadow);

Decl *ActOnUsingDeclaration(Scope *CurScope, AccessSpecifier AS,
                            SourceLocation UsingLoc,
                            SourceLocation TypenameLoc, CXXScopeSpec &SS,
                            UnqualifiedId &Name, SourceLocation EllipsisLoc,
                            const ParsedAttributesView &AttrList);
Decl *ActOnAliasDeclaration(Scope *CurScope, AccessSpecifier AS,
                            MultiTemplateParamsArg TemplateParams,
                            SourceLocation UsingLoc, UnqualifiedId &Name,
                            const ParsedAttributesView &AttrList,
                            TypeResult Type, Decl *DeclFromDeclSpec);

/// BuildCXXConstructExpr - Creates a complete call to a constructor,
/// including handling of its default argument expressions.
///
/// \param ConstructKind - a CXXConstructExpr::ConstructionKind
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      NamedDecl *FoundDecl,
                      CXXConstructorDecl *Constructor, MultiExprArg Exprs,
                      bool HadMultipleCandidates, bool IsListInitialization,
                      bool IsStdInitListInitialization,
                      bool RequiresZeroInit, unsigned ConstructKind,
                      SourceRange ParenRange);

/// Build a CXXConstructExpr whose constructor has already been resolved if
/// it denotes an inherited constructor.
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      CXXConstructorDecl *Constructor, bool Elidable,
                      MultiExprArg Exprs,
                      bool HadMultipleCandidates, bool IsListInitialization,
                      bool IsStdInitListInitialization,
                      bool RequiresZeroInit, unsigned ConstructKind,
                      SourceRange ParenRange);

// FIXME: Can we remove this and have the above BuildCXXConstructExpr check if
// the constructor can be elidable?
ExprResult
BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                      NamedDecl *FoundDecl,
                      CXXConstructorDecl *Constructor, bool Elidable,
                      MultiExprArg Exprs, bool HadMultipleCandidates,
                      bool IsListInitialization,
                      bool IsStdInitListInitialization, bool RequiresZeroInit,
                      unsigned ConstructKind, SourceRange ParenRange);

ExprResult BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field);


/// Instantiate or parse a C++ default argument expression as necessary.
/// Return true on error.
bool CheckCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
                            ParmVarDecl *Param);

/// BuildCXXDefaultArgExpr - Creates a CXXDefaultArgExpr, instantiating
/// the default expr if needed.
ExprResult BuildCXXDefaultArgExpr(SourceLocation CallLoc,
                                  FunctionDecl *FD,
                                  ParmVarDecl *Param);

/// FinalizeVarWithDestructor - Prepare for calling destructor on the
/// constructed variable.
void FinalizeVarWithDestructor(VarDecl *VD, const RecordType *DeclInitType);

/// Helper class that collects exception specifications for
/// implicitly-declared special member functions.
class ImplicitExceptionSpecification {
  // Pointer to allow copying
  Sema *Self;
  // We order exception specifications thus:
  // noexcept is the most restrictive, but is only used in C++11.
  // throw() comes next.
  // Then a throw(collected exceptions)
  // Finally no specification, which is expressed as noexcept(false).
  // throw(...) is used instead if any called function uses it.
  ExceptionSpecificationType ComputedEST;
  llvm::SmallPtrSet<CanQualType, 4> ExceptionsSeen;
  SmallVector<QualType, 4> Exceptions;

  void ClearExceptions() {
    ExceptionsSeen.clear();
    Exceptions.clear();
  }

public:
  explicit ImplicitExceptionSpecification(Sema &Self)
    : Self(&Self), ComputedEST(EST_BasicNoexcept) {
    if (!Self.getLangOpts().CPlusPlus11)
      ComputedEST = EST_DynamicNone;
  }

  /// Get the computed exception specification type.
  ExceptionSpecificationType getExceptionSpecType() const {
    assert(!isComputedNoexcept(ComputedEST) &&((!isComputedNoexcept(ComputedEST) && "noexcept(expr) should not be a possible result"
) ? static_cast<void> (0) : __assert_fail ("!isComputedNoexcept(ComputedEST) && \"noexcept(expr) should not be a possible result\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 5113, __PRETTY_FUNCTION__))
           "noexcept(expr) should not be a possible result")((!isComputedNoexcept(ComputedEST) && "noexcept(expr) should not be a possible result"
) ? static_cast<void> (0) : __assert_fail ("!isComputedNoexcept(ComputedEST) && \"noexcept(expr) should not be a possible result\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 5113, __PRETTY_FUNCTION__));
    return ComputedEST;
  }

  /// The number of exceptions in the exception specification.
  unsigned size() const { return Exceptions.size(); }

  /// The set of exceptions in the exception specification.
  const QualType *data() const { return Exceptions.data(); }

  /// Integrate another called method into the collected data.
  void CalledDecl(SourceLocation CallLoc, const CXXMethodDecl *Method);

  /// Integrate an invoked expression into the collected data.
  void CalledExpr(Expr *E);

  /// Overwrite an EPI's exception specification with this
  /// computed exception specification.
  FunctionProtoType::ExceptionSpecInfo getExceptionSpec() const {
    FunctionProtoType::ExceptionSpecInfo ESI;
    ESI.Type = getExceptionSpecType();
    if (ESI.Type == EST_Dynamic) {
      ESI.Exceptions = Exceptions;
    } else if (ESI.Type == EST_None) {
      /// C++11 [except.spec]p14:
      ///   The exception-specification is noexcept(false) if the set of
      ///   potential exceptions of the special member function contains "any"
      ESI.Type = EST_NoexceptFalse;
      ESI.NoexceptExpr = Self->ActOnCXXBoolLiteral(SourceLocation(),
                                                   tok::kw_false).get();
    }
    return ESI;
  }
};

/// Determine what sort of exception specification a defaulted
/// copy constructor of a class will have.
ImplicitExceptionSpecification
ComputeDefaultedDefaultCtorExceptionSpec(SourceLocation Loc,
                                         CXXMethodDecl *MD);

/// Determine what sort of exception specification a defaulted
/// default constructor of a class will have, and whether the parameter
/// will be const.
ImplicitExceptionSpecification
ComputeDefaultedCopyCtorExceptionSpec(CXXMethodDecl *MD);

/// Determine what sort of exception specification a defaulted
/// copy assignment operator of a class will have, and whether the
/// parameter will be const.
ImplicitExceptionSpecification
ComputeDefaultedCopyAssignmentExceptionSpec(CXXMethodDecl *MD);

/// Determine what sort of exception specification a defaulted move
/// constructor of a class will have.
ImplicitExceptionSpecification
ComputeDefaultedMoveCtorExceptionSpec(CXXMethodDecl *MD);

/// Determine what sort of exception specification a defaulted move
/// assignment operator of a class will have.
ImplicitExceptionSpecification
ComputeDefaultedMoveAssignmentExceptionSpec(CXXMethodDecl *MD);

/// Determine what sort of exception specification a defaulted
/// destructor of a class will have.
ImplicitExceptionSpecification
ComputeDefaultedDtorExceptionSpec(CXXMethodDecl *MD);

/// Determine what sort of exception specification an inheriting
/// constructor of a class will have.
ImplicitExceptionSpecification
ComputeInheritingCtorExceptionSpec(SourceLocation Loc,
                                   CXXConstructorDecl *CD);

/// Evaluate the implicit exception specification for a defaulted
/// special member function.
void EvaluateImplicitExceptionSpec(SourceLocation Loc, CXXMethodDecl *MD);

/// Check the given noexcept-specifier, convert its expression, and compute
/// the appropriate ExceptionSpecificationType.
ExprResult ActOnNoexceptSpec(SourceLocation NoexceptLoc, Expr *NoexceptExpr,
                             ExceptionSpecificationType &EST);

/// Check the given exception-specification and update the
/// exception specification information with the results.
void checkExceptionSpecification(bool IsTopLevel,
                                 ExceptionSpecificationType EST,
                                 ArrayRef<ParsedType> DynamicExceptions,
                                 ArrayRef<SourceRange> DynamicExceptionRanges,
                                 Expr *NoexceptExpr,
                                 SmallVectorImpl<QualType> &Exceptions,
                                 FunctionProtoType::ExceptionSpecInfo &ESI);

/// Determine if we're in a case where we need to (incorrectly) eagerly
/// parse an exception specification to work around a libstdc++ bug.
bool isLibstdcxxEagerExceptionSpecHack(const Declarator &D);

/// Add an exception-specification to the given member function
/// (or member function template). The exception-specification was parsed
/// after the method itself was declared.
void actOnDelayedExceptionSpecification(Decl *Method,
       ExceptionSpecificationType EST,
       SourceRange SpecificationRange,
       ArrayRef<ParsedType> DynamicExceptions,
       ArrayRef<SourceRange> DynamicExceptionRanges,
       Expr *NoexceptExpr);

class InheritedConstructorInfo;

/// Determine if a special member function should have a deleted
/// definition when it is defaulted.
bool ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMember CSM,
                               InheritedConstructorInfo *ICI = nullptr,
                               bool Diagnose = false);

/// Declare the implicit default constructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// default constructor will be added.
///
/// \returns The implicitly-declared default constructor.
CXXConstructorDecl *DeclareImplicitDefaultConstructor(
                                                   CXXRecordDecl *ClassDecl);

/// DefineImplicitDefaultConstructor - Checks for feasibility of
/// defining this constructor as the default constructor.
void DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
                                      CXXConstructorDecl *Constructor);

/// Declare the implicit destructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// destructor will be added.
///
/// \returns The implicitly-declared destructor.
CXXDestructorDecl *DeclareImplicitDestructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitDestructor - Checks for feasibility of
/// defining this destructor as the default destructor.
void DefineImplicitDestructor(SourceLocation CurrentLocation,
                              CXXDestructorDecl *Destructor);

/// Build an exception spec for destructors that don't have one.
///
/// C++11 says that user-defined destructors with no exception spec get one
/// that looks as if the destructor was implicitly declared.
void AdjustDestructorExceptionSpec(CXXDestructorDecl *Destructor);

/// Define the specified inheriting constructor.
void DefineInheritingConstructor(SourceLocation UseLoc,
                                 CXXConstructorDecl *Constructor);

/// Declare the implicit copy constructor for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// copy constructor will be added.
///
/// \returns The implicitly-declared copy constructor.
CXXConstructorDecl *DeclareImplicitCopyConstructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitCopyConstructor - Checks for feasibility of
/// defining this constructor as the copy constructor.
void DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
                                   CXXConstructorDecl *Constructor);

/// Declare the implicit move constructor for the given class.
///
/// \param ClassDecl The Class declaration into which the implicit
/// move constructor will be added.
///
/// \returns The implicitly-declared move constructor, or NULL if it wasn't
/// declared.
CXXConstructorDecl *DeclareImplicitMoveConstructor(CXXRecordDecl *ClassDecl);

/// DefineImplicitMoveConstructor - Checks for feasibility of
/// defining this constructor as the move constructor.
void DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
                                   CXXConstructorDecl *Constructor);

/// Declare the implicit copy assignment operator for the given class.
///
/// \param ClassDecl The class declaration into which the implicit
/// copy assignment operator will be added.
///
/// \returns The implicitly-declared copy assignment operator.
CXXMethodDecl *DeclareImplicitCopyAssignment(CXXRecordDecl *ClassDecl);

/// Defines an implicitly-declared copy assignment operator.
void DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
                                  CXXMethodDecl *MethodDecl);

/// Declare the implicit move assignment operator for the given class.
///
/// \param ClassDecl The Class declaration into which the implicit
/// move assignment operator will be added.
///
/// \returns The implicitly-declared move assignment operator, or NULL if it
/// wasn't declared.
CXXMethodDecl *DeclareImplicitMoveAssignment(CXXRecordDecl *ClassDecl);

/// Defines an implicitly-declared move assignment operator.
void DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
                                  CXXMethodDecl *MethodDecl);

/// Force the declaration of any implicitly-declared members of this
/// class.
void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);

/// Check a completed declaration of an implicit special member.
void CheckImplicitSpecialMemberDeclaration(Scope *S, FunctionDecl *FD);

/// Determine whether the given function is an implicitly-deleted
/// special member function.
bool isImplicitlyDeleted(FunctionDecl *FD);

/// Check whether 'this' shows up in the type of a static member
/// function after the (naturally empty) cv-qualifier-seq would be.
///
/// \returns true if an error occurred.
bool checkThisInStaticMemberFunctionType(CXXMethodDecl *Method);

/// Whether this' shows up in the exception specification of a static
/// member function.
bool checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method);

/// Check whether 'this' shows up in the attributes of the given
/// static member function.
///
/// \returns true if an error occurred.
bool checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method);

/// MaybeBindToTemporary - If the passed in expression has a record type with
/// a non-trivial destructor, this will return CXXBindTemporaryExpr. Otherwise
/// it simply returns the passed in expression.
ExprResult MaybeBindToTemporary(Expr *E);

bool CompleteConstructorCall(CXXConstructorDecl *Constructor,
                             MultiExprArg ArgsPtr,
                             SourceLocation Loc,
                             SmallVectorImpl<Expr*> &ConvertedArgs,
                             bool AllowExplicit = false,
                             bool IsListInitialization = false);

ParsedType getInheritingConstructorName(CXXScopeSpec &SS,
                                        SourceLocation NameLoc,
                                        IdentifierInfo &Name);

ParsedType getConstructorName(IdentifierInfo &II, SourceLocation NameLoc,
                              Scope *S, CXXScopeSpec &SS,
                              bool EnteringContext);
ParsedType getDestructorName(SourceLocation TildeLoc,
                             IdentifierInfo &II, SourceLocation NameLoc,
                             Scope *S, CXXScopeSpec &SS,
                             ParsedType ObjectType,
                             bool EnteringContext);

ParsedType getDestructorTypeForDecltype(const DeclSpec &DS,
                                        ParsedType ObjectType);

// Checks that reinterpret casts don't have undefined behavior.
void CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
                                    bool IsDereference, SourceRange Range);

/// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
ExprResult ActOnCXXNamedCast(SourceLocation OpLoc,
                             tok::TokenKind Kind,
                             SourceLocation LAngleBracketLoc,
                             Declarator &D,
                             SourceLocation RAngleBracketLoc,
                             SourceLocation LParenLoc,
                             Expr *E,
                             SourceLocation RParenLoc);

ExprResult BuildCXXNamedCast(SourceLocation OpLoc,
                             tok::TokenKind Kind,
                             TypeSourceInfo *Ty,
                             Expr *E,
                             SourceRange AngleBrackets,
                             SourceRange Parens);

ExprResult ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &Dcl,
                                   ExprResult Operand,
                                   SourceLocation RParenLoc);

ExprResult BuildBuiltinBitCastExpr(SourceLocation KWLoc, TypeSourceInfo *TSI,
                                   Expr *Operand, SourceLocation RParenLoc);

ExprResult BuildCXXTypeId(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          TypeSourceInfo *Operand,
                          SourceLocation RParenLoc);
ExprResult BuildCXXTypeId(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          Expr *Operand,
                          SourceLocation RParenLoc);

/// ActOnCXXTypeid - Parse typeid( something ).
ExprResult ActOnCXXTypeid(SourceLocation OpLoc,
                          SourceLocation LParenLoc, bool isType,
                          void *TyOrExpr,
                          SourceLocation RParenLoc);

ExprResult BuildCXXUuidof(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          TypeSourceInfo *Operand,
                          SourceLocation RParenLoc);
ExprResult BuildCXXUuidof(QualType TypeInfoType,
                          SourceLocation TypeidLoc,
                          Expr *Operand,
                          SourceLocation RParenLoc);

/// ActOnCXXUuidof - Parse __uuidof( something ).
ExprResult ActOnCXXUuidof(SourceLocation OpLoc,
                          SourceLocation LParenLoc, bool isType,
                          void *TyOrExpr,
                          SourceLocation RParenLoc);

/// Handle a C++1z fold-expression: ( expr op ... op expr ).
ExprResult ActOnCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
                            tok::TokenKind Operator,
                            SourceLocation EllipsisLoc, Expr *RHS,
                            SourceLocation RParenLoc);
ExprResult BuildCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
                            BinaryOperatorKind Operator,
                            SourceLocation EllipsisLoc, Expr *RHS,
                            SourceLocation RParenLoc,
                            Optional<unsigned> NumExpansions);
ExprResult BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
                                 BinaryOperatorKind Operator);

//// ActOnCXXThis -  Parse 'this' pointer.
ExprResult ActOnCXXThis(SourceLocation loc);

/// Build a CXXThisExpr and mark it referenced in the current context.
Expr *BuildCXXThisExpr(SourceLocation Loc, QualType Type, bool IsImplicit);
void MarkThisReferenced(CXXThisExpr *This);

/// Try to retrieve the type of the 'this' pointer.
///
/// \returns The type of 'this', if possible. Otherwise, returns a NULL type.
QualType getCurrentThisType();

/// When non-NULL, the C++ 'this' expression is allowed despite the
/// current context not being a non-static member function. In such cases,
/// this provides the type used for 'this'.
QualType CXXThisTypeOverride;

/// RAII object used to temporarily allow the C++ 'this' expression
/// to be used, with the given qualifiers on the current class type.
class CXXThisScopeRAII {
  Sema &S;
  QualType OldCXXThisTypeOverride;
  bool Enabled;

public:
  /// Introduce a new scope where 'this' may be allowed (when enabled),
  /// using the given declaration (which is either a class template or a
  /// class) along with the given qualifiers.
  /// along with the qualifiers placed on '*this'.
  CXXThisScopeRAII(Sema &S, Decl *ContextDecl, Qualifiers CXXThisTypeQuals,
                   bool Enabled = true);

  ~CXXThisScopeRAII();
};

/// Make sure the value of 'this' is actually available in the current
/// context, if it is a potentially evaluated context.
///
/// \param Loc The location at which the capture of 'this' occurs.
///
/// \param Explicit Whether 'this' is explicitly captured in a lambda
/// capture list.
///
/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
/// This is useful when enclosing lambdas must speculatively capture
/// 'this' that may or may not be used in certain specializations of
/// a nested generic lambda (depending on whether the name resolves to
/// a non-static member function or a static function).
/// \return returns 'true' if failed, 'false' if success.
bool CheckCXXThisCapture(SourceLocation Loc, bool Explicit = false,
    bool BuildAndDiagnose = true,
    const unsigned *const FunctionScopeIndexToStopAt = nullptr,
    bool ByCopy = false);

/// Determine whether the given type is the type of *this that is used
/// outside of the body of a member function for a type that is currently
/// being defined.
bool isThisOutsideMemberFunctionBody(QualType BaseType);

/// ActOnCXXBoolLiteral - Parse {true,false} literals.
ExprResult ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);


/// ActOnObjCBoolLiteral - Parse {__objc_yes,__objc_no} literals.
ExprResult ActOnObjCBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);

ExprResult
ActOnObjCAvailabilityCheckExpr(llvm::ArrayRef<AvailabilitySpec> AvailSpecs,
                               SourceLocation AtLoc, SourceLocation RParen);

/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
ExprResult ActOnCXXNullPtrLiteral(SourceLocation Loc);

//// ActOnCXXThrow -  Parse throw expressions.
ExprResult ActOnCXXThrow(Scope *S, SourceLocation OpLoc, Expr *expr);
ExprResult BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
                         bool IsThrownVarInScope);
bool CheckCXXThrowOperand(SourceLocation ThrowLoc, QualType ThrowTy, Expr *E);

/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
/// Can be interpreted either as function-style casting ("int(x)")
/// or class type construction ("ClassType(x,y,z)")
/// or creation of a value-initialized type ("int()").
ExprResult ActOnCXXTypeConstructExpr(ParsedType TypeRep,
                                     SourceLocation LParenOrBraceLoc,
                                     MultiExprArg Exprs,
                                     SourceLocation RParenOrBraceLoc,
                                     bool ListInitialization);

ExprResult BuildCXXTypeConstructExpr(TypeSourceInfo *Type,
                                     SourceLocation LParenLoc,
                                     MultiExprArg Exprs,
                                     SourceLocation RParenLoc,
                                     bool ListInitialization);

/// ActOnCXXNew - Parsed a C++ 'new' expression.
ExprResult ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
                       SourceLocation PlacementLParen,
                       MultiExprArg PlacementArgs,
                       SourceLocation PlacementRParen,
                       SourceRange TypeIdParens, Declarator &D,
                       Expr *Initializer);
ExprResult BuildCXXNew(SourceRange Range, bool UseGlobal,
                       SourceLocation PlacementLParen,
                       MultiExprArg PlacementArgs,
                       SourceLocation PlacementRParen,
                       SourceRange TypeIdParens,
                       QualType AllocType,
                       TypeSourceInfo *AllocTypeInfo,
                       Optional<Expr *> ArraySize,
                       SourceRange DirectInitRange,
                       Expr *Initializer);

/// Determine whether \p FD is an aligned allocation or deallocation
/// function that is unavailable.
bool isUnavailableAlignedAllocationFunction(const FunctionDecl &FD) const;

/// Produce diagnostics if \p FD is an aligned allocation or deallocation
/// function that is unavailable.
void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
                                          SourceLocation Loc);

bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
                        SourceRange R);

/// The scope in which to find allocation functions.
enum AllocationFunctionScope {
  /// Only look for allocation functions in the global scope.
  AFS_Global,
  /// Only look for allocation functions in the scope of the
  /// allocated class.
  AFS_Class,
  /// Look for allocation functions in both the global scope
  /// and in the scope of the allocated class.
  AFS_Both
};

/// Finds the overloads of operator new and delete that are appropriate
/// for the allocation.
bool FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
                             AllocationFunctionScope NewScope,
                             AllocationFunctionScope DeleteScope,
                             QualType AllocType, bool IsArray,
                             bool &PassAlignment, MultiExprArg PlaceArgs,
                             FunctionDecl *&OperatorNew,
                             FunctionDecl *&OperatorDelete,
                             bool Diagnose = true);
void DeclareGlobalNewDelete();
void DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return,
                                     ArrayRef<QualType> Params);

bool FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
                              DeclarationName Name, FunctionDecl* &Operator,
                              bool Diagnose = true);
FunctionDecl *FindUsualDeallocationFunction(SourceLocation StartLoc,
                                            bool CanProvideSize,
                                            bool Overaligned,
                                            DeclarationName Name);
FunctionDecl *FindDeallocationFunctionForDestructor(SourceLocation StartLoc,
                                                    CXXRecordDecl *RD);

/// ActOnCXXDelete - Parsed a C++ 'delete' expression
ExprResult ActOnCXXDelete(SourceLocation StartLoc,
                          bool UseGlobal, bool ArrayForm,
                          Expr *Operand);
void CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
                          bool IsDelete, bool CallCanBeVirtual,
                          bool WarnOnNonAbstractTypes,
                          SourceLocation DtorLoc);

ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
                             Expr *Operand, SourceLocation RParen);
ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
                                SourceLocation RParen);

/// Parsed one of the type trait support pseudo-functions.
ExprResult ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                          ArrayRef<ParsedType> Args,
                          SourceLocation RParenLoc);
ExprResult BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                          ArrayRef<TypeSourceInfo *> Args,
                          SourceLocation RParenLoc);

/// ActOnArrayTypeTrait - Parsed one of the binary type trait support
/// pseudo-functions.
ExprResult ActOnArrayTypeTrait(ArrayTypeTrait ATT,
                               SourceLocation KWLoc,
                               ParsedType LhsTy,
                               Expr *DimExpr,
                               SourceLocation RParen);

ExprResult BuildArrayTypeTrait(ArrayTypeTrait ATT,
                               SourceLocation KWLoc,
                               TypeSourceInfo *TSInfo,
                               Expr *DimExpr,
                               SourceLocation RParen);

/// ActOnExpressionTrait - Parsed one of the unary type trait support
/// pseudo-functions.
ExprResult ActOnExpressionTrait(ExpressionTrait OET,
                                SourceLocation KWLoc,
                                Expr *Queried,
                                SourceLocation RParen);

ExprResult BuildExpressionTrait(ExpressionTrait OET,
                                SourceLocation KWLoc,
                                Expr *Queried,
                                SourceLocation RParen);

ExprResult ActOnStartCXXMemberReference(Scope *S,
                                        Expr *Base,
                                        SourceLocation OpLoc,
                                        tok::TokenKind OpKind,
                                        ParsedType &ObjectType,
                                        bool &MayBePseudoDestructor);

ExprResult BuildPseudoDestructorExpr(Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     const CXXScopeSpec &SS,
                                     TypeSourceInfo *ScopeType,
                                     SourceLocation CCLoc,
                                     SourceLocation TildeLoc,
                                   PseudoDestructorTypeStorage DestroyedType);

ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     CXXScopeSpec &SS,
                                     UnqualifiedId &FirstTypeName,
                                     SourceLocation CCLoc,
                                     SourceLocation TildeLoc,
                                     UnqualifiedId &SecondTypeName);

ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                     SourceLocation OpLoc,
                                     tok::TokenKind OpKind,
                                     SourceLocation TildeLoc,
                                     const DeclSpec& DS);

/// MaybeCreateExprWithCleanups - If the current full-expression
/// requires any cleanups, surround it with a ExprWithCleanups node.
/// Otherwise, just returns the passed-in expression.
Expr *MaybeCreateExprWithCleanups(Expr *SubExpr);
Stmt *MaybeCreateStmtWithCleanups(Stmt *SubStmt);
ExprResult MaybeCreateExprWithCleanups(ExprResult SubExpr);

MaterializeTemporaryExpr *
CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
                               bool BoundToLvalueReference);

ExprResult ActOnFinishFullExpr(Expr *Expr, bool DiscardedValue) {
  return ActOnFinishFullExpr(
      Expr, Expr ? Expr->getExprLoc() : SourceLocation(), DiscardedValue);
}
ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
                               bool DiscardedValue, bool IsConstexpr = false);
StmtResult ActOnFinishFullStmt(Stmt *Stmt);

// Marks SS invalid if it represents an incomplete type.
bool RequireCompleteDeclContext(CXXScopeSpec &SS, DeclContext *DC);

DeclContext *computeDeclContext(QualType T);
DeclContext *computeDeclContext(const CXXScopeSpec &SS,
                                bool EnteringContext = false);
bool isDependentScopeSpecifier(const CXXScopeSpec &SS);
CXXRecordDecl *getCurrentInstantiationOf(NestedNameSpecifier *NNS);

/// The parser has parsed a global nested-name-specifier '::'.
///
/// \param CCLoc The location of the '::'.
///
/// \param SS The nested-name-specifier, which will be updated in-place
/// to reflect the parsed nested-name-specifier.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, CXXScopeSpec &SS);

/// The parser has parsed a '__super' nested-name-specifier.
///
/// \param SuperLoc The location of the '__super' keyword.
///
/// \param ColonColonLoc The location of the '::'.
///
/// \param SS The nested-name-specifier, which will be updated in-place
/// to reflect the parsed nested-name-specifier.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
                              SourceLocation ColonColonLoc, CXXScopeSpec &SS);

bool isAcceptableNestedNameSpecifier(const NamedDecl *SD,
                                     bool *CanCorrect = nullptr);
NamedDecl *FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS);

/// Keeps information about an identifier in a nested-name-spec.
///
struct NestedNameSpecInfo {
  /// The type of the object, if we're parsing nested-name-specifier in
  /// a member access expression.
  ParsedType ObjectType;

  /// The identifier preceding the '::'.
  IdentifierInfo *Identifier;

  /// The location of the identifier.
  SourceLocation IdentifierLoc;

  /// The location of the '::'.
  SourceLocation CCLoc;

  /// Creates info object for the most typical case.
  NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
           SourceLocation ColonColonLoc, ParsedType ObjectType = ParsedType())
    : ObjectType(ObjectType), Identifier(II), IdentifierLoc(IdLoc),
      CCLoc(ColonColonLoc) {
  }

  NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
                     SourceLocation ColonColonLoc, QualType ObjectType)
    : ObjectType(ParsedType::make(ObjectType)), Identifier(II),
      IdentifierLoc(IdLoc), CCLoc(ColonColonLoc) {
  }
};

bool isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
                                  NestedNameSpecInfo &IdInfo);

bool BuildCXXNestedNameSpecifier(Scope *S,
                                 NestedNameSpecInfo &IdInfo,
                                 bool EnteringContext,
                                 CXXScopeSpec &SS,
                                 NamedDecl *ScopeLookupResult,
                                 bool ErrorRecoveryLookup,
                                 bool *IsCorrectedToColon = nullptr,
                                 bool OnlyNamespace = false);

/// The parser has parsed a nested-name-specifier 'identifier::'.
///
/// \param S The scope in which this nested-name-specifier occurs.
///
/// \param IdInfo Parser information about an identifier in the
/// nested-name-spec.
///
/// \param EnteringContext Whether we're entering the context nominated by
/// this nested-name-specifier.
///
/// \param SS The nested-name-specifier, which is both an input
/// parameter (the nested-name-specifier before this type) and an
/// output parameter (containing the full nested-name-specifier,
/// including this new type).
///
/// \param ErrorRecoveryLookup If true, then this method is called to improve
/// error recovery. In this case do not emit error message.
///
/// \param IsCorrectedToColon If not null, suggestions to replace '::' -> ':'
/// are allowed.  The bool value pointed by this parameter is set to 'true'
/// if the identifier is treated as if it was followed by ':', not '::'.
///
/// \param OnlyNamespace If true, only considers namespaces in lookup.
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXNestedNameSpecifier(Scope *S,
                                 NestedNameSpecInfo &IdInfo,
                                 bool EnteringContext,
                                 CXXScopeSpec &SS,
                                 bool ErrorRecoveryLookup = false,
                                 bool *IsCorrectedToColon = nullptr,
                                 bool OnlyNamespace = false);

ExprResult ActOnDecltypeExpression(Expr *E);

bool ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
                                         const DeclSpec &DS,
                                         SourceLocation ColonColonLoc);

bool IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
                               NestedNameSpecInfo &IdInfo,
                               bool EnteringContext);

/// The parser has parsed a nested-name-specifier
/// 'template[opt] template-name < template-args >::'.
///
/// \param S The scope in which this nested-name-specifier occurs.
///
/// \param SS The nested-name-specifier, which is both an input
/// parameter (the nested-name-specifier before this type) and an
/// output parameter (containing the full nested-name-specifier,
/// including this new type).
///
/// \param TemplateKWLoc the location of the 'template' keyword, if any.
/// \param TemplateName the template name.
/// \param TemplateNameLoc The location of the template name.
/// \param LAngleLoc The location of the opening angle bracket  ('<').
/// \param TemplateArgs The template arguments.
/// \param RAngleLoc The location of the closing angle bracket  ('>').
/// \param CCLoc The location of the '::'.
///
/// \param EnteringContext Whether we're entering the context of the
/// nested-name-specifier.
///
///
/// \returns true if an error occurred, false otherwise.
bool ActOnCXXNestedNameSpecifier(Scope *S,
                                 CXXScopeSpec &SS,
                                 SourceLocation TemplateKWLoc,
                                 TemplateTy TemplateName,
                                 SourceLocation TemplateNameLoc,
                                 SourceLocation LAngleLoc,
                                 ASTTemplateArgsPtr TemplateArgs,
                                 SourceLocation RAngleLoc,
                                 SourceLocation CCLoc,
                                 bool EnteringContext);

/// Given a C++ nested-name-specifier, produce an annotation value
/// that the parser can use later to reconstruct the given
/// nested-name-specifier.
///
/// \param SS A nested-name-specifier.
///
/// \returns A pointer containing all of the information in the
/// nested-name-specifier \p SS.
void *SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS);

/// Given an annotation pointer for a nested-name-specifier, restore
/// the nested-name-specifier structure.
///
/// \param Annotation The annotation pointer, produced by
/// \c SaveNestedNameSpecifierAnnotation().
///
/// \param AnnotationRange The source range corresponding to the annotation.
///
/// \param SS The nested-name-specifier that will be updated with the contents
/// of the annotation pointer.
void RestoreNestedNameSpecifierAnnotation(void *Annotation,
                                          SourceRange AnnotationRange,
                                          CXXScopeSpec &SS);

bool ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
/// scope or nested-name-specifier) is parsed, part of a declarator-id.
/// After this method is called, according to [C++ 3.4.3p3], names should be
/// looked up in the declarator-id's scope, until the declarator is parsed and
/// ActOnCXXExitDeclaratorScope is called.
/// The 'SS' should be a non-empty valid CXXScopeSpec.
bool ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS);

/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
/// Used to indicate that names should revert to being looked up in the
/// defining scope.
void ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

/// ActOnCXXEnterDeclInitializer - Invoked when we are about to parse an
/// initializer for the declaration 'Dcl'.
/// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
/// static data member of class X, names should be looked up in the scope of
/// class X.
void ActOnCXXEnterDeclInitializer(Scope *S, Decl *Dcl);

/// ActOnCXXExitDeclInitializer - Invoked after we are finished parsing an
/// initializer for the declaration 'Dcl'.
void ActOnCXXExitDeclInitializer(Scope *S, Decl *Dcl);

/// Create a new lambda closure type.
CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange,
                                       TypeSourceInfo *Info,
                                       bool KnownDependent,
                                       LambdaCaptureDefault CaptureDefault);

/// Start the definition of a lambda expression.
CXXMethodDecl *
startLambdaDefinition(CXXRecordDecl *Class, SourceRange IntroducerRange,
                      TypeSourceInfo *MethodType, SourceLocation EndLoc,
                      ArrayRef<ParmVarDecl *> Params,
                      ConstexprSpecKind ConstexprKind,
                      Optional<std::pair<unsigned, Decl *>> Mangling = None);

/// Endow the lambda scope info with the relevant properties.
void buildLambdaScope(sema::LambdaScopeInfo *LSI,
                      CXXMethodDecl *CallOperator,
                      SourceRange IntroducerRange,
                      LambdaCaptureDefault CaptureDefault,
                      SourceLocation CaptureDefaultLoc,
                      bool ExplicitParams,
                      bool ExplicitResultType,
                      bool Mutable);

/// Perform initialization analysis of the init-capture and perform
/// any implicit conversions such as an lvalue-to-rvalue conversion if
/// not being used to initialize a reference.
ParsedType actOnLambdaInitCaptureInitialization(
    SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
    IdentifierInfo *Id, LambdaCaptureInitKind InitKind, Expr *&Init) {
  return ParsedType::make(buildLambdaInitCaptureInitialization(
      Loc, ByRef, EllipsisLoc, None, Id,
      InitKind != LambdaCaptureInitKind::CopyInit, Init));
}
QualType buildLambdaInitCaptureInitialization(
    SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
    Optional<unsigned> NumExpansions, IdentifierInfo *Id, bool DirectInit,
    Expr *&Init);

/// Create a dummy variable within the declcontext of the lambda's
///  call operator, for name lookup purposes for a lambda init capture.
///
///  CodeGen handles emission of lambda captures, ignoring these dummy
///  variables appropriately.
VarDecl *createLambdaInitCaptureVarDecl(SourceLocation Loc,
                                        QualType InitCaptureType,
                                        SourceLocation EllipsisLoc,
                                        IdentifierInfo *Id,
                                        unsigned InitStyle, Expr *Init);

/// Add an init-capture to a lambda scope.
void addInitCapture(sema::LambdaScopeInfo *LSI, VarDecl *Var);

/// Note that we have finished the explicit captures for the
/// given lambda.
void finishLambdaExplicitCaptures(sema::LambdaScopeInfo *LSI);

/// \brief This is called after parsing the explicit template parameter list
/// on a lambda (if it exists) in C++2a.
void ActOnLambdaExplicitTemplateParameterList(SourceLocation LAngleLoc,
                                              ArrayRef<NamedDecl *> TParams,
                                              SourceLocation RAngleLoc);

/// Introduce the lambda parameters into scope.
void addLambdaParameters(
    ArrayRef<LambdaIntroducer::LambdaCapture> Captures,
    CXXMethodDecl *CallOperator, Scope *CurScope);

/// Deduce a block or lambda's return type based on the return
/// statements present in the body.
void deduceClosureReturnType(sema::CapturingScopeInfo &CSI);

/// ActOnStartOfLambdaDefinition - This is called just before we start
/// parsing the body of a lambda; it analyzes the explicit captures and
/// arguments, and sets up various data-structures for the body of the
/// lambda.
void ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
                                  Declarator &ParamInfo, Scope *CurScope);

/// ActOnLambdaError - If there is an error parsing a lambda, this callback
/// is invoked to pop the information about the lambda.
void ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
                      bool IsInstantiation = false);

/// ActOnLambdaExpr - This is called when the body of a lambda expression
/// was successfully completed.
ExprResult ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body,
                           Scope *CurScope);

/// Does copying/destroying the captured variable have side effects?
bool CaptureHasSideEffects(const sema::Capture &From);

/// Diagnose if an explicit lambda capture is unused. Returns true if a
/// diagnostic is emitted.
bool DiagnoseUnusedLambdaCapture(SourceRange CaptureRange,
                                 const sema::Capture &From);

/// Build a FieldDecl suitable to hold the given capture.
FieldDecl *BuildCaptureField(RecordDecl *RD, const sema::Capture &Capture);

/// Initialize the given capture with a suitable expression.
ExprResult BuildCaptureInit(const sema::Capture &Capture,
                            SourceLocation ImplicitCaptureLoc,
                            bool IsOpenMPMapping = false);

/// Complete a lambda-expression having processed and attached the
/// lambda body.
ExprResult BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
                           sema::LambdaScopeInfo *LSI);

/// Get the return type to use for a lambda's conversion function(s) to
/// function pointer type, given the type of the call operator.
QualType
getLambdaConversionFunctionResultType(const FunctionProtoType *CallOpType);

/// Define the "body" of the conversion from a lambda object to a
/// function pointer.
///
/// This routine doesn't actually define a sensible body; rather, it fills
/// in the initialization expression needed to copy the lambda object into
/// the block, and IR generation actually generates the real body of the
/// block pointer conversion.
void DefineImplicitLambdaToFunctionPointerConversion(
       SourceLocation CurrentLoc, CXXConversionDecl *Conv);

/// Define the "body" of the conversion from a lambda object to a
/// block pointer.
///
/// This routine doesn't actually define a sensible body; rather, it fills
/// in the initialization expression needed to copy the lambda object into
/// the block, and IR generation actually generates the real body of the
/// block pointer conversion.
void DefineImplicitLambdaToBlockPointerConversion(SourceLocation CurrentLoc,
                                                  CXXConversionDecl *Conv);

ExprResult BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
                                         SourceLocation ConvLocation,
                                         CXXConversionDecl *Conv,
                                         Expr *Src);

// ParseObjCStringLiteral - Parse Objective-C string literals.
ExprResult ParseObjCStringLiteral(SourceLocation *AtLocs,
                                  ArrayRef<Expr *> Strings);

ExprResult BuildObjCStringLiteral(SourceLocation AtLoc, StringLiteral *S);

/// BuildObjCNumericLiteral - builds an ObjCBoxedExpr AST node for the
/// numeric literal expression. Type of the expression will be "NSNumber *"
/// or "id" if NSNumber is unavailable.
ExprResult BuildObjCNumericLiteral(SourceLocation AtLoc, Expr *Number);
ExprResult ActOnObjCBoolLiteral(SourceLocation AtLoc, SourceLocation ValueLoc,
                                bool Value);
ExprResult BuildObjCArrayLiteral(SourceRange SR, MultiExprArg Elements);

/// BuildObjCBoxedExpr - builds an ObjCBoxedExpr AST node for the
/// '@' prefixed parenthesized expression. The type of the expression will
/// either be "NSNumber *", "NSString *" or "NSValue *" depending on the type
/// of ValueType, which is allowed to be a built-in numeric type, "char *",
/// "const char *" or C structure with attribute 'objc_boxable'.
ExprResult BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr);

ExprResult BuildObjCSubscriptExpression(SourceLocation RB, Expr *BaseExpr,
                                        Expr *IndexExpr,
                                        ObjCMethodDecl *getterMethod,
                                        ObjCMethodDecl *setterMethod);

ExprResult BuildObjCDictionaryLiteral(SourceRange SR,
                             MutableArrayRef<ObjCDictionaryElement> Elements);

ExprResult BuildObjCEncodeExpression(SourceLocation AtLoc,
                                TypeSourceInfo *EncodedTypeInfo,
                                SourceLocation RParenLoc);
ExprResult BuildCXXMemberCallExpr(Expr *Exp, NamedDecl *FoundDecl,
                                  CXXConversionDecl *Method,
                                  bool HadMultipleCandidates);

ExprResult ParseObjCEncodeExpression(SourceLocation AtLoc,
                                     SourceLocation EncodeLoc,
                                     SourceLocation LParenLoc,
                                     ParsedType Ty,
                                     SourceLocation RParenLoc);

/// ParseObjCSelectorExpression - Build selector expression for \@selector
ExprResult ParseObjCSelectorExpression(Selector Sel,
                                       SourceLocation AtLoc,
                                       SourceLocation SelLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation RParenLoc,
                                       bool WarnMultipleSelectors);

/// ParseObjCProtocolExpression - Build protocol expression for \@protocol
ExprResult ParseObjCProtocolExpression(IdentifierInfo * ProtocolName,
                                       SourceLocation AtLoc,
                                       SourceLocation ProtoLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation ProtoIdLoc,
                                       SourceLocation RParenLoc);

//===--------------------------------------------------------------------===//
// C++ Declarations
//
Decl *ActOnStartLinkageSpecification(Scope *S,
                                     SourceLocation ExternLoc,
                                     Expr *LangStr,
                                     SourceLocation LBraceLoc);
Decl *ActOnFinishLinkageSpecification(Scope *S,
                                      Decl *LinkageSpec,
                                      SourceLocation RBraceLoc);


//===--------------------------------------------------------------------===//
// C++ Classes
//
CXXRecordDecl *getCurrentClass(Scope *S, const CXXScopeSpec *SS);
bool isCurrentClassName(const IdentifierInfo &II, Scope *S,
                        const CXXScopeSpec *SS = nullptr);
bool isCurrentClassNameTypo(IdentifierInfo *&II, const CXXScopeSpec *SS);

bool ActOnAccessSpecifier(AccessSpecifier Access, SourceLocation ASLoc,
                          SourceLocation ColonLoc,
                          const ParsedAttributesView &Attrs);

NamedDecl *ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS,
                               Declarator &D,
                               MultiTemplateParamsArg TemplateParameterLists,
                               Expr *BitfieldWidth, const VirtSpecifiers &VS,
                               InClassInitStyle InitStyle);

void ActOnStartCXXInClassMemberInitializer();
void ActOnFinishCXXInClassMemberInitializer(Decl *VarDecl,
                                            SourceLocation EqualLoc,
                                            Expr *Init);

MemInitResult ActOnMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  SourceLocation LParenLoc,
                                  ArrayRef<Expr *> Args,
                                  SourceLocation RParenLoc,
                                  SourceLocation EllipsisLoc);

MemInitResult ActOnMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  Expr *InitList,
                                  SourceLocation EllipsisLoc);

MemInitResult BuildMemInitializer(Decl *ConstructorD,
                                  Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *MemberOrBase,
                                  ParsedType TemplateTypeTy,
                                  const DeclSpec &DS,
                                  SourceLocation IdLoc,
                                  Expr *Init,
                                  SourceLocation EllipsisLoc);

MemInitResult BuildMemberInitializer(ValueDecl *Member,
                                     Expr *Init,
                                     SourceLocation IdLoc);

MemInitResult BuildBaseInitializer(QualType BaseType,
                                   TypeSourceInfo *BaseTInfo,
                                   Expr *Init,
                                   CXXRecordDecl *ClassDecl,
                                   SourceLocation EllipsisLoc);

MemInitResult BuildDelegatingInitializer(TypeSourceInfo *TInfo,
                                         Expr *Init,
                                         CXXRecordDecl *ClassDecl);

bool SetDelegatingInitializer(CXXConstructorDecl *Constructor,
                              CXXCtorInitializer *Initializer);

bool SetCtorInitializers(CXXConstructorDecl *Constructor, bool AnyErrors,
                         ArrayRef<CXXCtorInitializer *> Initializers = None);

void SetIvarInitializers(ObjCImplementationDecl *ObjCImplementation);


/// MarkBaseAndMemberDestructorsReferenced - Given a record decl,
/// mark all the non-trivial destructors of its members and bases as
/// referenced.
void MarkBaseAndMemberDestructorsReferenced(SourceLocation Loc,
                                            CXXRecordDecl *Record);

/// The list of classes whose vtables have been used within
/// this translation unit, and the source locations at which the
/// first use occurred.
typedef std::pair<CXXRecordDecl*, SourceLocation> VTableUse;

/// The list of vtables that are required but have not yet been
/// materialized.
SmallVector<VTableUse, 16> VTableUses;

/// The set of classes whose vtables have been used within
/// this translation unit, and a bit that will be true if the vtable is
/// required to be emitted (otherwise, it should be emitted only if needed
/// by code generation).
llvm::DenseMap<CXXRecordDecl *, bool> VTablesUsed;

/// Load any externally-stored vtable uses.
void LoadExternalVTableUses();

/// Note that the vtable for the given class was used at the
/// given location.
void MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
                    bool DefinitionRequired = false);

/// Mark the exception specifications of all virtual member functions
/// in the given class as needed.
void MarkVirtualMemberExceptionSpecsNeeded(SourceLocation Loc,
                                           const CXXRecordDecl *RD);

/// MarkVirtualMembersReferenced - Will mark all members of the given
/// CXXRecordDecl referenced.
void MarkVirtualMembersReferenced(SourceLocation Loc, const CXXRecordDecl *RD,
                                  bool ConstexprOnly = false);

/// Define all of the vtables that have been used in this
/// translation unit and reference any virtual members used by those
/// vtables.
///
/// \returns true if any work was done, false otherwise.
bool DefineUsedVTables();

void AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl);

void ActOnMemInitializers(Decl *ConstructorDecl,
                          SourceLocation ColonLoc,
                          ArrayRef<CXXCtorInitializer*> MemInits,
                          bool AnyErrors);

/// Check class-level dllimport/dllexport attribute. The caller must
/// ensure that referenceDLLExportedClassMethods is called some point later
/// when all outer classes of Class are complete.
void checkClassLevelDLLAttribute(CXXRecordDecl *Class);
void checkClassLevelCodeSegAttribute(CXXRecordDecl *Class);

void referenceDLLExportedClassMethods();

void propagateDLLAttrToBaseClassTemplate(
    CXXRecordDecl *Class, Attr *ClassAttr,
    ClassTemplateSpecializationDecl *BaseTemplateSpec,
    SourceLocation BaseLoc);

/// Add gsl::Pointer attribute to std::container::iterator
/// \param ND The declaration that introduces the name
/// std::container::iterator. \param UnderlyingRecord The record named by ND.
void inferGslPointerAttribute(NamedDecl *ND, CXXRecordDecl *UnderlyingRecord);

/// Add [[gsl::Owner]] and [[gsl::Pointer]] attributes for std:: types.
void inferGslOwnerPointerAttribute(CXXRecordDecl *Record);

/// Add [[gsl::Pointer]] attributes for std:: types.
void inferGslPointerAttribute(TypedefNameDecl *TD);

void CheckCompletedCXXClass(CXXRecordDecl *Record);

/// Check that the C++ class annoated with "trivial_abi" satisfies all the
/// conditions that are needed for the attribute to have an effect.
void checkIllFormedTrivialABIStruct(CXXRecordDecl &RD);

void ActOnFinishCXXMemberSpecification(Scope *S, SourceLocation RLoc,
                                       Decl *TagDecl, SourceLocation LBrac,
                                       SourceLocation RBrac,
                                       const ParsedAttributesView &AttrList);
void ActOnFinishCXXMemberDecls();
void ActOnFinishCXXNonNestedClass(Decl *D);

void ActOnReenterCXXMethodParameter(Scope *S, ParmVarDecl *Param);
unsigned ActOnReenterTemplateScope(Scope *S, Decl *Template);
void ActOnStartDelayedMemberDeclarations(Scope *S, Decl *Record);
void ActOnStartDelayedCXXMethodDeclaration(Scope *S, Decl *Method);
void ActOnDelayedCXXMethodParameter(Scope *S, Decl *Param);
void ActOnFinishDelayedMemberDeclarations(Scope *S, Decl *Record);
void ActOnFinishDelayedCXXMethodDeclaration(Scope *S, Decl *Method);
void ActOnFinishDelayedMemberInitializers(Decl *Record);
void MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
                              CachedTokens &Toks);
void UnmarkAsLateParsedTemplate(FunctionDecl *FD);
bool IsInsideALocalClassWithinATemplateFunction();

Decl *ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                   Expr *AssertExpr,
                                   Expr *AssertMessageExpr,
                                   SourceLocation RParenLoc);
Decl *BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                   Expr *AssertExpr,
                                   StringLiteral *AssertMessageExpr,
                                   SourceLocation RParenLoc,
                                   bool Failed);

FriendDecl *CheckFriendTypeDecl(SourceLocation LocStart,
                                SourceLocation FriendLoc,
                                TypeSourceInfo *TSInfo);
Decl *ActOnFriendTypeDecl(Scope *S, const DeclSpec &DS,
                          MultiTemplateParamsArg TemplateParams);
NamedDecl *ActOnFriendFunctionDecl(Scope *S, Declarator &D,
                                   MultiTemplateParamsArg TemplateParams);

QualType CheckConstructorDeclarator(Declarator &D, QualType R,
                                    StorageClass& SC);
void CheckConstructor(CXXConstructorDecl *Constructor);
QualType CheckDestructorDeclarator(Declarator &D, QualType R,
                                   StorageClass& SC);
bool CheckDestructor(CXXDestructorDecl *Destructor);
void CheckConversionDeclarator(Declarator &D, QualType &R,
                               StorageClass& SC);
Decl *ActOnConversionDeclarator(CXXConversionDecl *Conversion);
void CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
                                   StorageClass &SC);
void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);

void CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD);
void CheckDelayedMemberExceptionSpecs();

//===--------------------------------------------------------------------===//
// C++ Derived Classes
//

/// ActOnBaseSpecifier - Parsed a base specifier
CXXBaseSpecifier *CheckBaseSpecifier(CXXRecordDecl *Class,
                                     SourceRange SpecifierRange,
                                     bool Virtual, AccessSpecifier Access,
                                     TypeSourceInfo *TInfo,
                                     SourceLocation EllipsisLoc);

BaseResult ActOnBaseSpecifier(Decl *classdecl,
                              SourceRange SpecifierRange,
                              ParsedAttributes &Attrs,
                              bool Virtual, AccessSpecifier Access,
                              ParsedType basetype,
                              SourceLocation BaseLoc,
                              SourceLocation EllipsisLoc);

bool AttachBaseSpecifiers(CXXRecordDecl *Class,
                          MutableArrayRef<CXXBaseSpecifier *> Bases);
void ActOnBaseSpecifiers(Decl *ClassDecl,
                         MutableArrayRef<CXXBaseSpecifier *> Bases);

bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base);
bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base,
                   CXXBasePaths &Paths);

// FIXME: I don't like this name.
void BuildBasePathArray(const CXXBasePaths &Paths, CXXCastPath &BasePath);

bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                  SourceLocation Loc, SourceRange Range,
                                  CXXCastPath *BasePath = nullptr,
                                  bool IgnoreAccess = false);
bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
                                  unsigned InaccessibleBaseID,
                                  unsigned AmbigiousBaseConvID,
                                  SourceLocation Loc, SourceRange Range,
                                  DeclarationName Name,
                                  CXXCastPath *BasePath,
                                  bool IgnoreAccess = false);

std::string getAmbiguousPathsDisplayString(CXXBasePaths &Paths);

bool CheckOverridingFunctionAttributes(const CXXMethodDecl *New,
                                       const CXXMethodDecl *Old);

/// CheckOverridingFunctionReturnType - Checks whether the return types are
/// covariant, according to C++ [class.virtual]p5.
bool CheckOverridingFunctionReturnType(const CXXMethodDecl *New,
                                       const CXXMethodDecl *Old);

/// CheckOverridingFunctionExceptionSpec - Checks whether the exception
/// spec is a subset of base spec.
bool CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
                                          const CXXMethodDecl *Old);

bool CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange);

/// CheckOverrideControl - Check C++11 override control semantics.
void CheckOverrideControl(NamedDecl *D);

/// DiagnoseAbsenceOfOverrideControl - Diagnose if 'override' keyword was
/// not used in the declaration of an overriding method.
void DiagnoseAbsenceOfOverrideControl(NamedDecl *D);

/// CheckForFunctionMarkedFinal - Checks whether a virtual member function
/// overrides a virtual member function marked 'final', according to
/// C++11 [class.virtual]p4.
bool CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
                                            const CXXMethodDecl *Old);


//===--------------------------------------------------------------------===//
// C++ Access Control
//

enum AccessResult {
  AR_accessible,
  AR_inaccessible,
  AR_dependent,
  AR_delayed
};

bool SetMemberAccessSpecifier(NamedDecl *MemberDecl,
                              NamedDecl *PrevMemberDecl,
                              AccessSpecifier LexicalAS);

AccessResult CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
                                         DeclAccessPair FoundDecl);
AccessResult CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
                                         DeclAccessPair FoundDecl);
AccessResult CheckAllocationAccess(SourceLocation OperatorLoc,
                                   SourceRange PlacementRange,
                                   CXXRecordDecl *NamingClass,
                                   DeclAccessPair FoundDecl,
                                   bool Diagnose = true);
AccessResult CheckConstructorAccess(SourceLocation Loc,
                                    CXXConstructorDecl *D,
                                    DeclAccessPair FoundDecl,
                                    const InitializedEntity &Entity,
                                    bool IsCopyBindingRefToTemp = false);
AccessResult CheckConstructorAccess(SourceLocation Loc,
                                    CXXConstructorDecl *D,
                                    DeclAccessPair FoundDecl,
                                    const InitializedEntity &Entity,
                                    const PartialDiagnostic &PDiag);
AccessResult CheckDestructorAccess(SourceLocation Loc,
                                   CXXDestructorDecl *Dtor,
                                   const PartialDiagnostic &PDiag,
                                   QualType objectType = QualType());
AccessResult CheckFriendAccess(NamedDecl *D);
AccessResult CheckMemberAccess(SourceLocation UseLoc,
                               CXXRecordDecl *NamingClass,
                               DeclAccessPair Found);
AccessResult
CheckStructuredBindingMemberAccess(SourceLocation UseLoc,
                                   CXXRecordDecl *DecomposedClass,
                                   DeclAccessPair Field);
AccessResult CheckMemberOperatorAccess(SourceLocation Loc,
                                       Expr *ObjectExpr,
                                       Expr *ArgExpr,
                                       DeclAccessPair FoundDecl);
AccessResult CheckAddressOfMemberAccess(Expr *OvlExpr,
                                        DeclAccessPair FoundDecl);
AccessResult CheckBaseClassAccess(SourceLocation AccessLoc,
                                  QualType Base, QualType Derived,
                                  const CXXBasePath &Path,
                                  unsigned DiagID,
                                  bool ForceCheck = false,
                                  bool ForceUnprivileged = false);
void CheckLookupAccess(const LookupResult &R);
bool IsSimplyAccessible(NamedDecl *Decl, CXXRecordDecl *NamingClass,
                        QualType BaseType);
bool isSpecialMemberAccessibleForDeletion(CXXMethodDecl *decl,
                                          AccessSpecifier access,
                                          QualType objectType);

void HandleDependentAccessCheck(const DependentDiagnostic &DD,
                       const MultiLevelTemplateArgumentList &TemplateArgs);
void PerformDependentDiagnostics(const DeclContext *Pattern,
                      const MultiLevelTemplateArgumentList &TemplateArgs);

void HandleDelayedAccessCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);

/// When true, access checking violations are treated as SFINAE
/// failures rather than hard errors.
bool AccessCheckingSFINAE;

enum AbstractDiagSelID {
  AbstractNone = -1,
  AbstractReturnType,
  AbstractParamType,
  AbstractVariableType,
  AbstractFieldType,
  AbstractIvarType,
  AbstractSynthesizedIvarType,
  AbstractArrayType
};

bool isAbstractType(SourceLocation Loc, QualType T);
bool RequireNonAbstractType(SourceLocation Loc, QualType T,
                            TypeDiagnoser &Diagnoser);
template <typename... Ts>
bool RequireNonAbstractType(SourceLocation Loc, QualType T, unsigned DiagID,
                            const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireNonAbstractType(Loc, T, Diagnoser);
}

void DiagnoseAbstractType(const CXXRecordDecl *RD);

//===--------------------------------------------------------------------===//
// C++ Overloaded Operators [C++ 13.5]
//

bool CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl);

bool CheckLiteralOperatorDeclaration(FunctionDecl *FnDecl);

//===--------------------------------------------------------------------===//
// C++ Templates [C++ 14]
//
void FilterAcceptableTemplateNames(LookupResult &R,
                                   bool AllowFunctionTemplates = true,
                                   bool AllowDependent = true);
bool hasAnyAcceptableTemplateNames(LookupResult &R,
                                   bool AllowFunctionTemplates = true,
                                   bool AllowDependent = true,
                                   bool AllowNonTemplateFunctions = false);
/// Try to interpret the lookup result D as a template-name.
///
/// \param D A declaration found by name lookup.
/// \param AllowFunctionTemplates Whether function templates should be
///        considered valid results.
/// \param AllowDependent Whether unresolved using declarations (that might
///        name templates) should be considered valid results.
NamedDecl *getAsTemplateNameDecl(NamedDecl *D,
                                 bool AllowFunctionTemplates = true,
                                 bool AllowDependent = true);

enum class AssumedTemplateKind {
  /// This is not assumed to be a template name.
  None,
  /// This is assumed to be a template name because lookup found nothing.
  FoundNothing,
  /// This is assumed to be a template name because lookup found one or more
  /// functions (but no function templates).
  FoundFunctions,
};
bool LookupTemplateName(LookupResult &R, Scope *S, CXXScopeSpec &SS,
                        QualType ObjectType, bool EnteringContext,
                        bool &MemberOfUnknownSpecialization,
                        SourceLocation TemplateKWLoc = SourceLocation(),
                        AssumedTemplateKind *ATK = nullptr);

TemplateNameKind isTemplateName(Scope *S,
                                CXXScopeSpec &SS,
                                bool hasTemplateKeyword,
                                const UnqualifiedId &Name,
                                ParsedType ObjectType,
                                bool EnteringContext,
                                TemplateTy &Template,
                                bool &MemberOfUnknownSpecialization);

/// Try to resolve an undeclared template name as a type template.
///
/// Sets II to the identifier corresponding to the template name, and updates
/// Name to a corresponding (typo-corrected) type template name and TNK to
/// the corresponding kind, if possible.
void ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &Name,
                                     TemplateNameKind &TNK,
                                     SourceLocation NameLoc,
                                     IdentifierInfo *&II);

bool resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
                                      SourceLocation NameLoc,
                                      bool Diagnose = true);

/// Determine whether a particular identifier might be the name in a C++1z
/// deduction-guide declaration.
bool isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
                          SourceLocation NameLoc,
                          ParsedTemplateTy *Template = nullptr);

bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,
                                 SourceLocation IILoc,
                                 Scope *S,
                                 const CXXScopeSpec *SS,
                                 TemplateTy &SuggestedTemplate,
                                 TemplateNameKind &SuggestedKind);

bool DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
                                    NamedDecl *Instantiation,
                                    bool InstantiatedFromMember,
                                    const NamedDecl *Pattern,
                                    const NamedDecl *PatternDef,
                                    TemplateSpecializationKind TSK,
                                    bool Complain = true);

void DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl);
TemplateDecl *AdjustDeclIfTemplate(Decl *&Decl);

NamedDecl *ActOnTypeParameter(Scope *S, bool Typename,
                         SourceLocation EllipsisLoc,
                         SourceLocation KeyLoc,
                         IdentifierInfo *ParamName,
                         SourceLocation ParamNameLoc,
                         unsigned Depth, unsigned Position,
                         SourceLocation EqualLoc,
                         ParsedType DefaultArg);

QualType CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
                                           SourceLocation Loc);
QualType CheckNonTypeTemplateParameterType(QualType T, SourceLocation Loc);

NamedDecl *ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
                                    unsigned Depth,
                                    unsigned Position,
                                    SourceLocation EqualLoc,
                                    Expr *DefaultArg);
NamedDecl *ActOnTemplateTemplateParameter(Scope *S,
                                     SourceLocation TmpLoc,
                                     TemplateParameterList *Params,
                                     SourceLocation EllipsisLoc,
                                     IdentifierInfo *ParamName,
                                     SourceLocation ParamNameLoc,
                                     unsigned Depth,
                                     unsigned Position,
                                     SourceLocation EqualLoc,
                                     ParsedTemplateArgument DefaultArg);

TemplateParameterList *
ActOnTemplateParameterList(unsigned Depth,
                           SourceLocation ExportLoc,
                           SourceLocation TemplateLoc,
                           SourceLocation LAngleLoc,
                           ArrayRef<NamedDecl *> Params,
                           SourceLocation RAngleLoc,
                           Expr *RequiresClause);

/// The context in which we are checking a template parameter list.
enum TemplateParamListContext {
  TPC_ClassTemplate,
  TPC_VarTemplate,
  TPC_FunctionTemplate,
  TPC_ClassTemplateMember,
  TPC_FriendClassTemplate,
  TPC_FriendFunctionTemplate,
  TPC_FriendFunctionTemplateDefinition,
  TPC_TypeAliasTemplate
};

bool CheckTemplateParameterList(TemplateParameterList *NewParams,
                                TemplateParameterList *OldParams,
                                TemplateParamListContext TPC,
                                SkipBodyInfo *SkipBody = nullptr);
TemplateParameterList *MatchTemplateParametersToScopeSpecifier(
    SourceLocation DeclStartLoc, SourceLocation DeclLoc,
    const CXXScopeSpec &SS, TemplateIdAnnotation *TemplateId,
    ArrayRef<TemplateParameterList *> ParamLists,
    bool IsFriend, bool &IsMemberSpecialization, bool &Invalid);

DeclResult CheckClassTemplate(
    Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
    CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
    const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
    AccessSpecifier AS, SourceLocation ModulePrivateLoc,
    SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
    TemplateParameterList **OuterTemplateParamLists,
    SkipBodyInfo *SkipBody = nullptr);

TemplateArgumentLoc getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
                                                  QualType NTTPType,
                                                  SourceLocation Loc);

void translateTemplateArguments(const ASTTemplateArgsPtr &In,
                                TemplateArgumentListInfo &Out);

ParsedTemplateArgument ActOnTemplateTypeArgument(TypeResult ParsedType);

void NoteAllFoundTemplates(TemplateName Name);

QualType CheckTemplateIdType(TemplateName Template,
                             SourceLocation TemplateLoc,
                            TemplateArgumentListInfo &TemplateArgs);

TypeResult
ActOnTemplateIdType(Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
                    TemplateTy Template, IdentifierInfo *TemplateII,
                    SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
                    ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc,
                    bool IsCtorOrDtorName = false, bool IsClassName = false);

/// Parsed an elaborated-type-specifier that refers to a template-id,
/// such as \c class T::template apply<U>.
TypeResult ActOnTagTemplateIdType(TagUseKind TUK,
                                  TypeSpecifierType TagSpec,
                                  SourceLocation TagLoc,
                                  CXXScopeSpec &SS,
                                  SourceLocation TemplateKWLoc,
                                  TemplateTy TemplateD,
                                  SourceLocation TemplateLoc,
                                  SourceLocation LAngleLoc,
                                  ASTTemplateArgsPtr TemplateArgsIn,
                                  SourceLocation RAngleLoc);

DeclResult ActOnVarTemplateSpecialization(
    Scope *S, Declarator &D, TypeSourceInfo *DI,
    SourceLocation TemplateKWLoc, TemplateParameterList *TemplateParams,
    StorageClass SC, bool IsPartialSpecialization);

DeclResult CheckVarTemplateId(VarTemplateDecl *Template,
                              SourceLocation TemplateLoc,
                              SourceLocation TemplateNameLoc,
                              const TemplateArgumentListInfo &TemplateArgs);

ExprResult CheckVarTemplateId(const CXXScopeSpec &SS,
                              const DeclarationNameInfo &NameInfo,
                              VarTemplateDecl *Template,
                              SourceLocation TemplateLoc,
                              const TemplateArgumentListInfo *TemplateArgs);

ExprResult
CheckConceptTemplateId(const CXXScopeSpec &SS,
                       const DeclarationNameInfo &NameInfo,
                       ConceptDecl *Template,
                       SourceLocation TemplateLoc,
                       const TemplateArgumentListInfo *TemplateArgs);

void diagnoseMissingTemplateArguments(TemplateName Name, SourceLocation Loc);

ExprResult BuildTemplateIdExpr(const CXXScopeSpec &SS,
                               SourceLocation TemplateKWLoc,
                               LookupResult &R,
                               bool RequiresADL,
                             const TemplateArgumentListInfo *TemplateArgs);

ExprResult BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
                                        SourceLocation TemplateKWLoc,
                             const DeclarationNameInfo &NameInfo,
                             const TemplateArgumentListInfo *TemplateArgs);

TemplateNameKind ActOnDependentTemplateName(
    Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
    const UnqualifiedId &Name, ParsedType ObjectType, bool EnteringContext,
    TemplateTy &Template, bool AllowInjectedClassName = false);

DeclResult ActOnClassTemplateSpecialization(
    Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
    SourceLocation ModulePrivateLoc, TemplateIdAnnotation &TemplateId,
    const ParsedAttributesView &Attr,
    MultiTemplateParamsArg TemplateParameterLists,
    SkipBodyInfo *SkipBody = nullptr);

bool CheckTemplatePartialSpecializationArgs(SourceLocation Loc,
                                            TemplateDecl *PrimaryTemplate,
                                            unsigned NumExplicitArgs,
                                            ArrayRef<TemplateArgument> Args);
void CheckTemplatePartialSpecialization(
    ClassTemplatePartialSpecializationDecl *Partial);
void CheckTemplatePartialSpecialization(
    VarTemplatePartialSpecializationDecl *Partial);

Decl *ActOnTemplateDeclarator(Scope *S,
                              MultiTemplateParamsArg TemplateParameterLists,
                              Declarator &D);

bool
CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
                                       TemplateSpecializationKind NewTSK,
                                       NamedDecl *PrevDecl,
                                       TemplateSpecializationKind PrevTSK,
                                       SourceLocation PrevPtOfInstantiation,
                                       bool &SuppressNew);

bool CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
                  const TemplateArgumentListInfo &ExplicitTemplateArgs,
                                                  LookupResult &Previous);

bool CheckFunctionTemplateSpecialization(
    FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
    LookupResult &Previous, bool QualifiedFriend = false);
bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
void CompleteMemberSpecialization(NamedDecl *Member, LookupResult &Previous);

DeclResult ActOnExplicitInstantiation(
    Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
    unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
    TemplateTy Template, SourceLocation TemplateNameLoc,
    SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
    SourceLocation RAngleLoc, const ParsedAttributesView &Attr);

DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
                                      SourceLocation TemplateLoc,
                                      unsigned TagSpec, SourceLocation KWLoc,
                                      CXXScopeSpec &SS, IdentifierInfo *Name,
                                      SourceLocation NameLoc,
                                      const ParsedAttributesView &Attr);

DeclResult ActOnExplicitInstantiation(Scope *S,
                                      SourceLocation ExternLoc,
                                      SourceLocation TemplateLoc,
                                      Declarator &D);

TemplateArgumentLoc
SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
                                        SourceLocation TemplateLoc,
                                        SourceLocation RAngleLoc,
                                        Decl *Param,
                                        SmallVectorImpl<TemplateArgument>
                                          &Converted,
                                        bool &HasDefaultArg);

/// Specifies the context in which a particular template
/// argument is being checked.
enum CheckTemplateArgumentKind {
  /// The template argument was specified in the code or was
  /// instantiated with some deduced template arguments.
  CTAK_Specified,

  /// The template argument was deduced via template argument
  /// deduction.
  CTAK_Deduced,

  /// The template argument was deduced from an array bound
  /// via template argument deduction.
  CTAK_DeducedFromArrayBound
};

bool CheckTemplateArgument(NamedDecl *Param,
                           TemplateArgumentLoc &Arg,
                           NamedDecl *Template,
                           SourceLocation TemplateLoc,
                           SourceLocation RAngleLoc,
                           unsigned ArgumentPackIndex,
                         SmallVectorImpl<TemplateArgument> &Converted,
                           CheckTemplateArgumentKind CTAK = CTAK_Specified);

/// Check that the given template arguments can be be provided to
/// the given template, converting the arguments along the way.
///
/// \param Template The template to which the template arguments are being
/// provided.
///
/// \param TemplateLoc The location of the template name in the source.
///
/// \param TemplateArgs The list of template arguments. If the template is
/// a template template parameter, this function may extend the set of
/// template arguments to also include substituted, defaulted template
/// arguments.
///
/// \param PartialTemplateArgs True if the list of template arguments is
/// intentionally partial, e.g., because we're checking just the initial
/// set of template arguments.
///
/// \param Converted Will receive the converted, canonicalized template
/// arguments.
///
/// \param UpdateArgsWithConversions If \c true, update \p TemplateArgs to
/// contain the converted forms of the template arguments as written.
/// Otherwise, \p TemplateArgs will not be modified.
///
/// \returns true if an error occurred, false otherwise.
bool CheckTemplateArgumentList(TemplateDecl *Template,
                               SourceLocation TemplateLoc,
                               TemplateArgumentListInfo &TemplateArgs,
                               bool PartialTemplateArgs,
                               SmallVectorImpl<TemplateArgument> &Converted,
                               bool UpdateArgsWithConversions = true);

bool CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
                               TemplateArgumentLoc &Arg,
                         SmallVectorImpl<TemplateArgument> &Converted);

bool CheckTemplateArgument(TemplateTypeParmDecl *Param,
                           TypeSourceInfo *Arg);
ExprResult CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
                                 QualType InstantiatedParamType, Expr *Arg,
                                 TemplateArgument &Converted,
                             CheckTemplateArgumentKind CTAK = CTAK_Specified);
bool CheckTemplateTemplateArgument(TemplateParameterList *Params,
                                   TemplateArgumentLoc &Arg);

ExprResult
BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
                                        QualType ParamType,
                                        SourceLocation Loc);
ExprResult
BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
                                            SourceLocation Loc);

/// Enumeration describing how template parameter lists are compared
/// for equality.
enum TemplateParameterListEqualKind {
  /// We are matching the template parameter lists of two templates
  /// that might be redeclarations.
  ///
  /// \code
  /// template<typename T> struct X;
  /// template<typename T> struct X;
  /// \endcode
  TPL_TemplateMatch,

  /// We are matching the template parameter lists of two template
  /// template parameters as part of matching the template parameter lists
  /// of two templates that might be redeclarations.
  ///
  /// \code
  /// template<template<int I> class TT> struct X;
  /// template<template<int Value> class Other> struct X;
  /// \endcode
  TPL_TemplateTemplateParmMatch,

  /// We are matching the template parameter lists of a template
  /// template argument against the template parameter lists of a template
  /// template parameter.
  ///
  /// \code
  /// template<template<int Value> class Metafun> struct X;
  /// template<int Value> struct integer_c;
  /// X<integer_c> xic;
  /// \endcode
  TPL_TemplateTemplateArgumentMatch
};

bool TemplateParameterListsAreEqual(TemplateParameterList *New,
                                    TemplateParameterList *Old,
                                    bool Complain,
                                    TemplateParameterListEqualKind Kind,
                                    SourceLocation TemplateArgLoc
                                      = SourceLocation());

bool CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams);

/// Called when the parser has parsed a C++ typename
/// specifier, e.g., "typename T::type".
///
/// \param S The scope in which this typename type occurs.
/// \param TypenameLoc the location of the 'typename' keyword
/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
/// \param II the identifier we're retrieving (e.g., 'type' in the example).
/// \param IdLoc the location of the identifier.
TypeResult
ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
                  const CXXScopeSpec &SS, const IdentifierInfo &II,
                  SourceLocation IdLoc);

/// Called when the parser has parsed a C++ typename
/// specifier that ends in a template-id, e.g.,
/// "typename MetaFun::template apply<T1, T2>".
///
/// \param S The scope in which this typename type occurs.
/// \param TypenameLoc the location of the 'typename' keyword
/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
/// \param TemplateLoc the location of the 'template' keyword, if any.
/// \param TemplateName The template name.
/// \param TemplateII The identifier used to name the template.
/// \param TemplateIILoc The location of the template name.
/// \param LAngleLoc The location of the opening angle bracket  ('<').
/// \param TemplateArgs The template arguments.
/// \param RAngleLoc The location of the closing angle bracket  ('>').
TypeResult
ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
                  const CXXScopeSpec &SS,
                  SourceLocation TemplateLoc,
                  TemplateTy TemplateName,
                  IdentifierInfo *TemplateII,
                  SourceLocation TemplateIILoc,
                  SourceLocation LAngleLoc,
                  ASTTemplateArgsPtr TemplateArgs,
                  SourceLocation RAngleLoc);

QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
                           SourceLocation KeywordLoc,
                           NestedNameSpecifierLoc QualifierLoc,
                           const IdentifierInfo &II,
                           SourceLocation IILoc);

TypeSourceInfo *RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
                                                  SourceLocation Loc,
                                                  DeclarationName Name);
bool RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS);

ExprResult RebuildExprInCurrentInstantiation(Expr *E);
bool RebuildTemplateParamsInCurrentInstantiation(
                                              TemplateParameterList *Params);

std::string
getTemplateArgumentBindingsText(const TemplateParameterList *Params,
                                const TemplateArgumentList &Args);

std::string
getTemplateArgumentBindingsText(const TemplateParameterList *Params,
                                const TemplateArgument *Args,
                                unsigned NumArgs);

// Concepts
Decl *ActOnConceptDefinition(
    Scope *S, MultiTemplateParamsArg TemplateParameterLists,
    IdentifierInfo *Name, SourceLocation NameLoc, Expr *ConstraintExpr);

//===--------------------------------------------------------------------===//
// C++ Variadic Templates (C++0x [temp.variadic])
//===--------------------------------------------------------------------===//

/// Determine whether an unexpanded parameter pack might be permitted in this
/// location. Useful for error recovery.
bool isUnexpandedParameterPackPermitted();

/// The context in which an unexpanded parameter pack is
/// being diagnosed.
///
/// Note that the values of this enumeration line up with the first
/// argument to the \c err_unexpanded_parameter_pack diagnostic.
enum UnexpandedParameterPackContext {
  /// An arbitrary expression.
  UPPC_Expression = 0,

  /// The base type of a class type.
  UPPC_BaseType,

  /// The type of an arbitrary declaration.
  UPPC_DeclarationType,

  /// The type of a data member.
  UPPC_DataMemberType,

  /// The size of a bit-field.
  UPPC_BitFieldWidth,

  /// The expression in a static assertion.
  UPPC_StaticAssertExpression,

  /// The fixed underlying type of an enumeration.
  UPPC_FixedUnderlyingType,

  /// The enumerator value.
  UPPC_EnumeratorValue,

  /// A using declaration.
  UPPC_UsingDeclaration,

  /// A friend declaration.
  UPPC_FriendDeclaration,

  /// A declaration qualifier.
  UPPC_DeclarationQualifier,

  /// An initializer.
  UPPC_Initializer,

  /// A default argument.
  UPPC_DefaultArgument,

  /// The type of a non-type template parameter.
  UPPC_NonTypeTemplateParameterType,

  /// The type of an exception.
  UPPC_ExceptionType,

  /// Partial specialization.
  UPPC_PartialSpecialization,

  /// Microsoft __if_exists.
  UPPC_IfExists,

  /// Microsoft __if_not_exists.
  UPPC_IfNotExists,

  /// Lambda expression.
  UPPC_Lambda,

  /// Block expression,
  UPPC_Block
};

/// Diagnose unexpanded parameter packs.
///
/// \param Loc The location at which we should emit the diagnostic.
///
/// \param UPPC The context in which we are diagnosing unexpanded
/// parameter packs.
///
/// \param Unexpanded the set of unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPacks(SourceLocation Loc,
                                      UnexpandedParameterPackContext UPPC,
                                ArrayRef<UnexpandedParameterPack> Unexpanded);

/// If the given type contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param Loc The source location where a diagnostc should be emitted.
///
/// \param T The type that is being checked for unexpanded parameter
/// packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(SourceLocation Loc, TypeSourceInfo *T,
                                     UnexpandedParameterPackContext UPPC);

/// If the given expression contains an unexpanded parameter
/// pack, diagnose the error.
///
/// \param E The expression that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(Expr *E,
                     UnexpandedParameterPackContext UPPC = UPPC_Expression);

/// If the given nested-name-specifier contains an unexpanded
/// parameter pack, diagnose the error.
///
/// \param SS The nested-name-specifier that is being checked for
/// unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
                                     UnexpandedParameterPackContext UPPC);

/// If the given name contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param NameInfo The name (with source location information) that
/// is being checked for unexpanded parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
                                     UnexpandedParameterPackContext UPPC);

/// If the given template name contains an unexpanded parameter pack,
/// diagnose the error.
///
/// \param Loc The location of the template name.
///
/// \param Template The template name that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(SourceLocation Loc,
                                     TemplateName Template,
                                     UnexpandedParameterPackContext UPPC);

/// If the given template argument contains an unexpanded parameter
/// pack, diagnose the error.
///
/// \param Arg The template argument that is being checked for unexpanded
/// parameter packs.
///
/// \returns true if an error occurred, false otherwise.
bool DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
                                     UnexpandedParameterPackContext UPPC);

/// Collect the set of unexpanded parameter packs within the given
/// template argument.
///
/// \param Arg The template argument that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TemplateArgument Arg,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// template argument.
///
/// \param Arg The template argument that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TemplateArgumentLoc Arg,
                  SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// type.
///
/// \param T The type that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(QualType T,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// type.
///
/// \param TL The type that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(TypeLoc TL,
                 SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// nested-name-specifier.
///
/// \param NNS The nested-name-specifier that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(NestedNameSpecifierLoc NNS,
                       SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Collect the set of unexpanded parameter packs within the given
/// name.
///
/// \param NameInfo The name that will be traversed to find
/// unexpanded parameter packs.
void collectUnexpandedParameterPacks(const DeclarationNameInfo &NameInfo,
                       SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);

/// Invoked when parsing a template argument followed by an
/// ellipsis, which creates a pack expansion.
///
/// \param Arg The template argument preceding the ellipsis, which
/// may already be invalid.
///
/// \param EllipsisLoc The location of the ellipsis.
ParsedTemplateArgument ActOnPackExpansion(const ParsedTemplateArgument &Arg,
                                          SourceLocation EllipsisLoc);

/// Invoked when parsing a type followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Type The type preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
TypeResult ActOnPackExpansion(ParsedType Type, SourceLocation EllipsisLoc);

/// Construct a pack expansion type from the pattern of the pack
/// expansion.
TypeSourceInfo *CheckPackExpansion(TypeSourceInfo *Pattern,
                                   SourceLocation EllipsisLoc,
                                   Optional<unsigned> NumExpansions);

/// Construct a pack expansion type from the pattern of the pack
/// expansion.
QualType CheckPackExpansion(QualType Pattern,
                            SourceRange PatternRange,
                            SourceLocation EllipsisLoc,
                            Optional<unsigned> NumExpansions);

/// Invoked when parsing an expression followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Pattern The expression preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
ExprResult ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc);

/// Invoked when parsing an expression followed by an ellipsis, which
/// creates a pack expansion.
///
/// \param Pattern The expression preceding the ellipsis, which will become
/// the pattern of the pack expansion.
///
/// \param EllipsisLoc The location of the ellipsis.
ExprResult CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
                              Optional<unsigned> NumExpansions);

/// Determine whether we could expand a pack expansion with the
/// given set of parameter packs into separate arguments by repeatedly
/// transforming the pattern.
///
/// \param EllipsisLoc The location of the ellipsis that identifies the
/// pack expansion.
///
/// \param PatternRange The source range that covers the entire pattern of
/// the pack expansion.
///
/// \param Unexpanded The set of unexpanded parameter packs within the
/// pattern.
///
/// \param ShouldExpand Will be set to \c true if the transformer should
/// expand the corresponding pack expansions into separate arguments. When
/// set, \c NumExpansions must also be set.
///
/// \param RetainExpansion Whether the caller should add an unexpanded
/// pack expansion after all of the expanded arguments. This is used
/// when extending explicitly-specified template argument packs per
/// C++0x [temp.arg.explicit]p9.
///
/// \param NumExpansions The number of separate arguments that will be in
/// the expanded form of the corresponding pack expansion. This is both an
/// input and an output parameter, which can be set by the caller if the
/// number of expansions is known a priori (e.g., due to a prior substitution)
/// and will be set by the callee when the number of expansions is known.
/// The callee must set this value when \c ShouldExpand is \c true; it may
/// set this value in other cases.
///
/// \returns true if an error occurred (e.g., because the parameter packs
/// are to be instantiated with arguments of different lengths), false
/// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions)
/// must be set.
bool CheckParameterPacksForExpansion(SourceLocation EllipsisLoc,
                                     SourceRange PatternRange,
                           ArrayRef<UnexpandedParameterPack> Unexpanded,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                                     bool &ShouldExpand,
                                     bool &RetainExpansion,
                                     Optional<unsigned> &NumExpansions);

/// Determine the number of arguments in the given pack expansion
/// type.
///
/// This routine assumes that the number of arguments in the expansion is
/// consistent across all of the unexpanded parameter packs in its pattern.
///
/// Returns an empty Optional if the type can't be expanded.
Optional<unsigned> getNumArgumentsInExpansion(QualType T,
    const MultiLevelTemplateArgumentList &TemplateArgs);

/// Determine whether the given declarator contains any unexpanded
/// parameter packs.
///
/// This routine is used by the parser to disambiguate function declarators
/// with an ellipsis prior to the ')', e.g.,
///
/// \code
///   void f(T...);
/// \endcode
///
/// To determine whether we have an (unnamed) function parameter pack or
/// a variadic function.
///
/// \returns true if the declarator contains any unexpanded parameter packs,
/// false otherwise.
bool containsUnexpandedParameterPacks(Declarator &D);

/// Returns the pattern of the pack expansion for a template argument.
///
/// \param OrigLoc The template argument to expand.
///
/// \param Ellipsis Will be set to the location of the ellipsis.
///
/// \param NumExpansions Will be set to the number of expansions that will
/// be generated from this pack expansion, if known a priori.
TemplateArgumentLoc getTemplateArgumentPackExpansionPattern(
    TemplateArgumentLoc OrigLoc,
    SourceLocation &Ellipsis,
    Optional<unsigned> &NumExpansions) const;

/// Given a template argument that contains an unexpanded parameter pack, but
/// which has already been substituted, attempt to determine the number of
/// elements that will be produced once this argument is fully-expanded.
///
/// This is intended for use when transforming 'sizeof...(Arg)' in order to
/// avoid actually expanding the pack where possible.
Optional<unsigned> getFullyPackExpandedSize(TemplateArgument Arg);

//===--------------------------------------------------------------------===//
// C++ Template Argument Deduction (C++ [temp.deduct])
//===--------------------------------------------------------------------===//

/// Adjust the type \p ArgFunctionType to match the calling convention,
/// noreturn, and optionally the exception specification of \p FunctionType.
/// Deduction often wants to ignore these properties when matching function
/// types.
QualType adjustCCAndNoReturn(QualType ArgFunctionType, QualType FunctionType,
                             bool AdjustExceptionSpec = false);

/// Describes the result of template argument deduction.
///
/// The TemplateDeductionResult enumeration describes the result of
/// template argument deduction, as returned from
/// DeduceTemplateArguments(). The separate TemplateDeductionInfo
/// structure provides additional information about the results of
/// template argument deduction, e.g., the deduced template argument
/// list (if successful) or the specific template parameters or
/// deduced arguments that were involved in the failure.
enum TemplateDeductionResult {
  /// Template argument deduction was successful.
  TDK_Success = 0,
  /// The declaration was invalid; do nothing.
  TDK_Invalid,
  /// Template argument deduction exceeded the maximum template
  /// instantiation depth (which has already been diagnosed).
  TDK_InstantiationDepth,
  /// Template argument deduction did not deduce a value
  /// for every template parameter.
  TDK_Incomplete,
  /// Template argument deduction did not deduce a value for every
  /// expansion of an expanded template parameter pack.
  TDK_IncompletePack,
  /// Template argument deduction produced inconsistent
  /// deduced values for the given template parameter.
  TDK_Inconsistent,
  /// Template argument deduction failed due to inconsistent
  /// cv-qualifiers on a template parameter type that would
  /// otherwise be deduced, e.g., we tried to deduce T in "const T"
  /// but were given a non-const "X".
  TDK_Underqualified,
  /// Substitution of the deduced template argument values
  /// resulted in an error.
  TDK_SubstitutionFailure,
  /// After substituting deduced template arguments, a dependent
  /// parameter type did not match the corresponding argument.
  TDK_DeducedMismatch,
  /// After substituting deduced template arguments, an element of
  /// a dependent parameter type did not match the corresponding element
  /// of the corresponding argument (when deducing from an initializer list).
  TDK_DeducedMismatchNested,
  /// A non-depnedent component of the parameter did not match the
  /// corresponding component of the argument.
  TDK_NonDeducedMismatch,
  /// When performing template argument deduction for a function
  /// template, there were too many call arguments.
  TDK_TooManyArguments,
  /// When performing template argument deduction for a function
  /// template, there were too few call arguments.
  TDK_TooFewArguments,
  /// The explicitly-specified template arguments were not valid
  /// template arguments for the given template.
  TDK_InvalidExplicitArguments,
  /// Checking non-dependent argument conversions failed.
  TDK_NonDependentConversionFailure,
  /// Deduction failed; that's all we know.
  TDK_MiscellaneousDeductionFailure,
  /// CUDA Target attributes do not match.
  TDK_CUDATargetMismatch
};

TemplateDeductionResult
DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
                        const TemplateArgumentList &TemplateArgs,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult
DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
                        const TemplateArgumentList &TemplateArgs,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult SubstituteExplicitTemplateArguments(
    FunctionTemplateDecl *FunctionTemplate,
    TemplateArgumentListInfo &ExplicitTemplateArgs,
    SmallVectorImpl<DeducedTemplateArgument> &Deduced,
    SmallVectorImpl<QualType> &ParamTypes, QualType *FunctionType,
    sema::TemplateDeductionInfo &Info);

/// brief A function argument from which we performed template argument
// deduction for a call.
struct OriginalCallArg {
  OriginalCallArg(QualType OriginalParamType, bool DecomposedParam,
                  unsigned ArgIdx, QualType OriginalArgType)
      : OriginalParamType(OriginalParamType),
        DecomposedParam(DecomposedParam), ArgIdx(ArgIdx),
        OriginalArgType(OriginalArgType) {}

  QualType OriginalParamType;
  bool DecomposedParam;
  unsigned ArgIdx;
  QualType OriginalArgType;
};

TemplateDeductionResult FinishTemplateArgumentDeduction(
    FunctionTemplateDecl *FunctionTemplate,
    SmallVectorImpl<DeducedTemplateArgument> &Deduced,
    unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
    sema::TemplateDeductionInfo &Info,
    SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs = nullptr,
    bool PartialOverloading = false,
    llvm::function_ref<bool()> CheckNonDependent = []{ return false; });

TemplateDeductionResult DeduceTemplateArguments(
    FunctionTemplateDecl *FunctionTemplate,
    TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
    FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
    bool PartialOverloading,
    llvm::function_ref<bool(ArrayRef<QualType>)> CheckNonDependent);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        TemplateArgumentListInfo *ExplicitTemplateArgs,
                        QualType ArgFunctionType,
                        FunctionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info,
                        bool IsAddressOfFunction = false);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        QualType ToType,
                        CXXConversionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info);

TemplateDeductionResult
DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                        TemplateArgumentListInfo *ExplicitTemplateArgs,
                        FunctionDecl *&Specialization,
                        sema::TemplateDeductionInfo &Info,
                        bool IsAddressOfFunction = false);

/// Substitute Replacement for \p auto in \p TypeWithAuto
QualType SubstAutoType(QualType TypeWithAuto, QualType Replacement);
/// Substitute Replacement for auto in TypeWithAuto
TypeSourceInfo* SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
                                        QualType Replacement);
/// Completely replace the \c auto in \p TypeWithAuto by
/// \p Replacement. This does not retain any \c auto type sugar.
QualType ReplaceAutoType(QualType TypeWithAuto, QualType Replacement);

/// Result type of DeduceAutoType.
enum DeduceAutoResult {
  DAR_Succeeded,
  DAR_Failed,
  DAR_FailedAlreadyDiagnosed
};

DeduceAutoResult
DeduceAutoType(TypeSourceInfo *AutoType, Expr *&Initializer, QualType &Result,
               Optional<unsigned> DependentDeductionDepth = None);
DeduceAutoResult
DeduceAutoType(TypeLoc AutoTypeLoc, Expr *&Initializer, QualType &Result,
               Optional<unsigned> DependentDeductionDepth = None);
void DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init);
bool DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
                      bool Diagnose = true);

/// Declare implicit deduction guides for a class template if we've
/// not already done so.
void DeclareImplicitDeductionGuides(TemplateDecl *Template,
                                    SourceLocation Loc);

QualType DeduceTemplateSpecializationFromInitializer(
    TypeSourceInfo *TInfo, const InitializedEntity &Entity,
    const InitializationKind &Kind, MultiExprArg Init);

QualType deduceVarTypeFromInitializer(VarDecl *VDecl, DeclarationName Name,
                                      QualType Type, TypeSourceInfo *TSI,
                                      SourceRange Range, bool DirectInit,
                                      Expr *Init);

TypeLoc getReturnTypeLoc(FunctionDecl *FD) const;

bool DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
                                      SourceLocation ReturnLoc,
                                      Expr *&RetExpr, AutoType *AT);

FunctionTemplateDecl *getMoreSpecializedTemplate(FunctionTemplateDecl *FT1,
                                                 FunctionTemplateDecl *FT2,
                                                 SourceLocation Loc,
                                         TemplatePartialOrderingContext TPOC,
                                                 unsigned NumCallArguments1,
                                                 unsigned NumCallArguments2);
UnresolvedSetIterator
getMostSpecialized(UnresolvedSetIterator SBegin, UnresolvedSetIterator SEnd,
                   TemplateSpecCandidateSet &FailedCandidates,
                   SourceLocation Loc,
                   const PartialDiagnostic &NoneDiag,
                   const PartialDiagnostic &AmbigDiag,
                   const PartialDiagnostic &CandidateDiag,
                   bool Complain = true, QualType TargetType = QualType());

ClassTemplatePartialSpecializationDecl *
getMoreSpecializedPartialSpecialization(
                                ClassTemplatePartialSpecializationDecl *PS1,
                                ClassTemplatePartialSpecializationDecl *PS2,
                                SourceLocation Loc);

bool isMoreSpecializedThanPrimary(ClassTemplatePartialSpecializationDecl *T,
                                  sema::TemplateDeductionInfo &Info);

VarTemplatePartialSpecializationDecl *getMoreSpecializedPartialSpecialization(
    VarTemplatePartialSpecializationDecl *PS1,
    VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);

bool isMoreSpecializedThanPrimary(VarTemplatePartialSpecializationDecl *T,
                                  sema::TemplateDeductionInfo &Info);

bool isTemplateTemplateParameterAtLeastAsSpecializedAs(
    TemplateParameterList *P, TemplateDecl *AArg, SourceLocation Loc);

void MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
                                bool OnlyDeduced,
                                unsigned Depth,
                                llvm::SmallBitVector &Used);
void MarkDeducedTemplateParameters(
                                const FunctionTemplateDecl *FunctionTemplate,
                                llvm::SmallBitVector &Deduced) {
  return MarkDeducedTemplateParameters(Context, FunctionTemplate, Deduced);
}
static void MarkDeducedTemplateParameters(ASTContext &Ctx,
                                const FunctionTemplateDecl *FunctionTemplate,
                                llvm::SmallBitVector &Deduced);

//===--------------------------------------------------------------------===//
// C++ Template Instantiation
//

MultiLevelTemplateArgumentList
getTemplateInstantiationArgs(NamedDecl *D,
                             const TemplateArgumentList *Innermost = nullptr,
                             bool RelativeToPrimary = false,
                             const FunctionDecl *Pattern = nullptr);

/// A context in which code is being synthesized (where a source location
/// alone is not sufficient to identify the context). This covers template
/// instantiation and various forms of implicitly-generated functions.
struct CodeSynthesisContext {
  /// The kind of template instantiation we are performing
  enum SynthesisKind {
    /// We are instantiating a template declaration. The entity is
    /// the declaration we're instantiating (e.g., a CXXRecordDecl).
    TemplateInstantiation,

    /// We are instantiating a default argument for a template
    /// parameter. The Entity is the template parameter whose argument is
    /// being instantiated, the Template is the template, and the
    /// TemplateArgs/NumTemplateArguments provide the template arguments as
    /// specified.
    DefaultTemplateArgumentInstantiation,

    /// We are instantiating a default argument for a function.
    /// The Entity is the ParmVarDecl, and TemplateArgs/NumTemplateArgs
    /// provides the template arguments as specified.
    DefaultFunctionArgumentInstantiation,

    /// We are substituting explicit template arguments provided for
    /// a function template. The entity is a FunctionTemplateDecl.
    ExplicitTemplateArgumentSubstitution,

    /// We are substituting template argument determined as part of
    /// template argument deduction for either a class template
    /// partial specialization or a function template. The
    /// Entity is either a {Class|Var}TemplatePartialSpecializationDecl or
    /// a TemplateDecl.
    DeducedTemplateArgumentSubstitution,

    /// We are substituting prior template arguments into a new
    /// template parameter. The template parameter itself is either a
    /// NonTypeTemplateParmDecl or a TemplateTemplateParmDecl.
    PriorTemplateArgumentSubstitution,

    /// We are checking the validity of a default template argument that
    /// has been used when naming a template-id.
    DefaultTemplateArgumentChecking,

    /// We are computing the exception specification for a defaulted special
    /// member function.
    ExceptionSpecEvaluation,

    /// We are instantiating the exception specification for a function
    /// template which was deferred until it was needed.
    ExceptionSpecInstantiation,

    /// We are declaring an implicit special member function.
    DeclaringSpecialMember,

    /// We are defining a synthesized function (such as a defaulted special
    /// member).
    DefiningSynthesizedFunction,

    /// Added for Template instantiation observation.
    /// Memoization means we are _not_ instantiating a template because
    /// it is already instantiated (but we entered a context where we
    /// would have had to if it was not already instantiated).
    Memoization
  } Kind;

  /// Was the enclosing context a non-instantiation SFINAE context?
  bool SavedInNonInstantiationSFINAEContext;

  /// The point of instantiation or synthesis within the source code.
  SourceLocation PointOfInstantiation;

  /// The entity that is being synthesized.
  Decl *Entity;

  /// The template (or partial specialization) in which we are
  /// performing the instantiation, for substitutions of prior template
  /// arguments.
  NamedDecl *Template;

  /// The list of template arguments we are substituting, if they
  /// are not part of the entity.
  const TemplateArgument *TemplateArgs;

  // FIXME: Wrap this union around more members, or perhaps store the
  // kind-specific members in the RAII object owning the context.
  union {
    /// The number of template arguments in TemplateArgs.
    unsigned NumTemplateArgs;

    /// The special member being declared or defined.
    CXXSpecialMember SpecialMember;
  };

  ArrayRef<TemplateArgument> template_arguments() const {
    assert(Kind != DeclaringSpecialMember)((Kind != DeclaringSpecialMember) ? static_cast<void> (
0) : __assert_fail ("Kind != DeclaringSpecialMember", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 7678, __PRETTY_FUNCTION__));
    return {TemplateArgs, NumTemplateArgs};
  }

  /// The template deduction info object associated with the
  /// substitution or checking of explicit or deduced template arguments.
  sema::TemplateDeductionInfo *DeductionInfo;

  /// The source range that covers the construct that cause
  /// the instantiation, e.g., the template-id that causes a class
  /// template instantiation.
  SourceRange InstantiationRange;

  CodeSynthesisContext()
      : Kind(TemplateInstantiation),
        SavedInNonInstantiationSFINAEContext(false), Entity(nullptr),
        Template(nullptr), TemplateArgs(nullptr), NumTemplateArgs(0),
        DeductionInfo(nullptr) {}

  /// Determines whether this template is an actual instantiation
  /// that should be counted toward the maximum instantiation depth.
  bool isInstantiationRecord() const;
};

/// List of active code synthesis contexts.
///
/// This vector is treated as a stack. As synthesis of one entity requires
/// synthesis of another, additional contexts are pushed onto the stack.
SmallVector<CodeSynthesisContext, 16> CodeSynthesisContexts;

/// Specializations whose definitions are currently being instantiated.
llvm::DenseSet<std::pair<Decl *, unsigned>> InstantiatingSpecializations;

/// Non-dependent types used in templates that have already been instantiated
/// by some template instantiation.
llvm::DenseSet<QualType> InstantiatedNonDependentTypes;

/// Extra modules inspected when performing a lookup during a template
/// instantiation. Computed lazily.
SmallVector<Module*, 16> CodeSynthesisContextLookupModules;

/// Cache of additional modules that should be used for name lookup
/// within the current template instantiation. Computed lazily; use
/// getLookupModules() to get a complete set.
llvm::DenseSet<Module*> LookupModulesCache;

/// Get the set of additional modules that should be checked during
/// name lookup. A module and its imports become visible when instanting a
/// template defined within it.
llvm::DenseSet<Module*> &getLookupModules();

/// Map from the most recent declaration of a namespace to the most
/// recent visible declaration of that namespace.
llvm::DenseMap<NamedDecl*, NamedDecl*> VisibleNamespaceCache;

/// Whether we are in a SFINAE context that is not associated with
/// template instantiation.
///
/// This is used when setting up a SFINAE trap (\c see SFINAETrap) outside
/// of a template instantiation or template argument deduction.
bool InNonInstantiationSFINAEContext;

/// The number of \p CodeSynthesisContexts that are not template
/// instantiations and, therefore, should not be counted as part of the
/// instantiation depth.
///
/// When the instantiation depth reaches the user-configurable limit
/// \p LangOptions::InstantiationDepth we will abort instantiation.
// FIXME: Should we have a similar limit for other forms of synthesis?
unsigned NonInstantiationEntries;

/// The depth of the context stack at the point when the most recent
/// error or warning was produced.
///
/// This value is used to suppress printing of redundant context stacks
/// when there are multiple errors or warnings in the same instantiation.
// FIXME: Does this belong in Sema? It's tough to implement it anywhere else.
unsigned LastEmittedCodeSynthesisContextDepth = 0;

/// The template instantiation callbacks to trace or track
/// instantiations (objects can be chained).
///
/// This callbacks is used to print, trace or track template
/// instantiations as they are being constructed.
std::vector<std::unique_ptr<TemplateInstantiationCallback>>
    TemplateInstCallbacks;

/// The current index into pack expansion arguments that will be
/// used for substitution of parameter packs.
///
/// The pack expansion index will be -1 to indicate that parameter packs
/// should be instantiated as themselves. Otherwise, the index specifies
/// which argument within the parameter pack will be used for substitution.
int ArgumentPackSubstitutionIndex;

/// RAII object used to change the argument pack substitution index
/// within a \c Sema object.
///
/// See \c ArgumentPackSubstitutionIndex for more information.
class ArgumentPackSubstitutionIndexRAII {
  Sema &Self;
  int OldSubstitutionIndex;

public:
  ArgumentPackSubstitutionIndexRAII(Sema &Self, int NewSubstitutionIndex)
    : Self(Self), OldSubstitutionIndex(Self.ArgumentPackSubstitutionIndex) {
    Self.ArgumentPackSubstitutionIndex = NewSubstitutionIndex;
  }

  ~ArgumentPackSubstitutionIndexRAII() {
    Self.ArgumentPackSubstitutionIndex = OldSubstitutionIndex;
  }
};

friend class ArgumentPackSubstitutionRAII;

/// For each declaration that involved template argument deduction, the
/// set of diagnostics that were suppressed during that template argument
/// deduction.
///
/// FIXME: Serialize this structure to the AST file.
typedef llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, 1> >
  SuppressedDiagnosticsMap;
SuppressedDiagnosticsMap SuppressedDiagnostics;

/// A stack object to be created when performing template
/// instantiation.
///
/// Construction of an object of type \c InstantiatingTemplate
/// pushes the current instantiation onto the stack of active
/// instantiations. If the size of this stack exceeds the maximum
/// number of recursive template instantiations, construction
/// produces an error and evaluates true.
///
/// Destruction of this object will pop the named instantiation off
/// the stack.
struct InstantiatingTemplate {
  /// Note that we are instantiating a class template,
  /// function template, variable template, alias template,
  /// or a member thereof.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        Decl *Entity,
                        SourceRange InstantiationRange = SourceRange());

  struct ExceptionSpecification {};
  /// Note that we are instantiating an exception specification
  /// of a function template.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        FunctionDecl *Entity, ExceptionSpecification,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating a default argument in a
  /// template-id.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateParameter Param, TemplateDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are substituting either explicitly-specified or
  /// deduced template arguments during function template argument deduction.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        FunctionTemplateDecl *FunctionTemplate,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        CodeSynthesisContext::SynthesisKind Kind,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a class template declaration.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateDecl *Template,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a class template partial
  /// specialization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ClassTemplatePartialSpecializationDecl *PartialSpec,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating as part of template
  /// argument deduction for a variable template partial
  /// specialization.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        VarTemplatePartialSpecializationDecl *PartialSpec,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        sema::TemplateDeductionInfo &DeductionInfo,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are instantiating a default argument for a function
  /// parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        ParmVarDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange = SourceRange());

  /// Note that we are substituting prior template arguments into a
  /// non-type parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        NamedDecl *Template,
                        NonTypeTemplateParmDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  /// Note that we are substituting prior template arguments into a
  /// template template parameter.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        NamedDecl *Template,
                        TemplateTemplateParmDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);

  /// Note that we are checking the default template argument
  /// against the template parameter for a given template-id.
  InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
                        TemplateDecl *Template,
                        NamedDecl *Param,
                        ArrayRef<TemplateArgument> TemplateArgs,
                        SourceRange InstantiationRange);


  /// Note that we have finished instantiating this template.
  void Clear();

  ~InstantiatingTemplate() { Clear(); }

  /// Determines whether we have exceeded the maximum
  /// recursive template instantiations.
  bool isInvalid() const { return Invalid; }

  /// Determine whether we are already instantiating this
  /// specialization in some surrounding active instantiation.
  bool isAlreadyInstantiating() const { return AlreadyInstantiating; }

private:
  Sema &SemaRef;
  bool Invalid;
  bool AlreadyInstantiating;
  bool CheckInstantiationDepth(SourceLocation PointOfInstantiation,
                               SourceRange InstantiationRange);

  InstantiatingTemplate(
      Sema &SemaRef, CodeSynthesisContext::SynthesisKind Kind,
      SourceLocation PointOfInstantiation, SourceRange InstantiationRange,
      Decl *Entity, NamedDecl *Template = nullptr,
      ArrayRef<TemplateArgument> TemplateArgs = None,
      sema::TemplateDeductionInfo *DeductionInfo = nullptr);

  InstantiatingTemplate(const InstantiatingTemplate&) = delete;

  InstantiatingTemplate&
  operator=(const InstantiatingTemplate&) = delete;
};

void pushCodeSynthesisContext(CodeSynthesisContext Ctx);
void popCodeSynthesisContext();

/// Determine whether we are currently performing template instantiation.
bool inTemplateInstantiation() const {
  return CodeSynthesisContexts.size() > NonInstantiationEntries;
}

void PrintContextStack() {
  if (!CodeSynthesisContexts.empty() &&
      CodeSynthesisContexts.size() != LastEmittedCodeSynthesisContextDepth) {
    PrintInstantiationStack();
    LastEmittedCodeSynthesisContextDepth = CodeSynthesisContexts.size();
  }
  if (PragmaAttributeCurrentTargetDecl)
    PrintPragmaAttributeInstantiationPoint();
}
void PrintInstantiationStack();

void PrintPragmaAttributeInstantiationPoint();

/// Determines whether we are currently in a context where
/// template argument substitution failures are not considered
/// errors.
///
/// \returns An empty \c Optional if we're not in a SFINAE context.
/// Otherwise, contains a pointer that, if non-NULL, contains the nearest
/// template-deduction context object, which can be used to capture
/// diagnostics that will be suppressed.
Optional<sema::TemplateDeductionInfo *> isSFINAEContext() const;

/// Determines whether we are currently in a context that
/// is not evaluated as per C++ [expr] p5.
bool isUnevaluatedContext() const {
  assert(!ExprEvalContexts.empty() &&((!ExprEvalContexts.empty() && "Must be in an expression evaluation context"
) ? static_cast<void> (0) : __assert_fail ("!ExprEvalContexts.empty() && \"Must be in an expression evaluation context\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 7971, __PRETTY_FUNCTION__))
         "Must be in an expression evaluation context")((!ExprEvalContexts.empty() && "Must be in an expression evaluation context"
) ? static_cast<void> (0) : __assert_fail ("!ExprEvalContexts.empty() && \"Must be in an expression evaluation context\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 7971, __PRETTY_FUNCTION__));
  return ExprEvalContexts.back().isUnevaluated();
}

/// RAII class used to determine whether SFINAE has
/// trapped any errors that occur during template argument
/// deduction.
class SFINAETrap {
  Sema &SemaRef;
  unsigned PrevSFINAEErrors;
  bool PrevInNonInstantiationSFINAEContext;
  bool PrevAccessCheckingSFINAE;
  bool PrevLastDiagnosticIgnored;

public:
  explicit SFINAETrap(Sema &SemaRef, bool AccessCheckingSFINAE = false)
    : SemaRef(SemaRef), PrevSFINAEErrors(SemaRef.NumSFINAEErrors),
      PrevInNonInstantiationSFINAEContext(
                                    SemaRef.InNonInstantiationSFINAEContext),
      PrevAccessCheckingSFINAE(SemaRef.AccessCheckingSFINAE),
      PrevLastDiagnosticIgnored(
          SemaRef.getDiagnostics().isLastDiagnosticIgnored())
  {
    if (!SemaRef.isSFINAEContext())
      SemaRef.InNonInstantiationSFINAEContext = true;
    SemaRef.AccessCheckingSFINAE = AccessCheckingSFINAE;
  }

  ~SFINAETrap() {
    SemaRef.NumSFINAEErrors = PrevSFINAEErrors;
    SemaRef.InNonInstantiationSFINAEContext
      = PrevInNonInstantiationSFINAEContext;
    SemaRef.AccessCheckingSFINAE = PrevAccessCheckingSFINAE;
    SemaRef.getDiagnostics().setLastDiagnosticIgnored(
        PrevLastDiagnosticIgnored);
  }

  /// Determine whether any SFINAE errors have been trapped.
  bool hasErrorOccurred() const {
    return SemaRef.NumSFINAEErrors > PrevSFINAEErrors;
  }
};

/// RAII class used to indicate that we are performing provisional
/// semantic analysis to determine the validity of a construct, so
/// typo-correction and diagnostics in the immediate context (not within
/// implicitly-instantiated templates) should be suppressed.
class TentativeAnalysisScope {
  Sema &SemaRef;
  // FIXME: Using a SFINAETrap for this is a hack.
  SFINAETrap Trap;
  bool PrevDisableTypoCorrection;
public:
  explicit TentativeAnalysisScope(Sema &SemaRef)
      : SemaRef(SemaRef), Trap(SemaRef, true),
        PrevDisableTypoCorrection(SemaRef.DisableTypoCorrection) {
    SemaRef.DisableTypoCorrection = true;
  }
  ~TentativeAnalysisScope() {
    SemaRef.DisableTypoCorrection = PrevDisableTypoCorrection;
  }
};

/// The current instantiation scope used to store local
/// variables.
LocalInstantiationScope *CurrentInstantiationScope;

/// Tracks whether we are in a context where typo correction is
/// disabled.
bool DisableTypoCorrection;

/// The number of typos corrected by CorrectTypo.
unsigned TyposCorrected;

typedef llvm::SmallSet<SourceLocation, 2> SrcLocSet;
typedef llvm::DenseMap<IdentifierInfo *, SrcLocSet> IdentifierSourceLocations;

/// A cache containing identifiers for which typo correction failed and
/// their locations, so that repeated attempts to correct an identifier in a
/// given location are ignored if typo correction already failed for it.
IdentifierSourceLocations TypoCorrectionFailures;

/// Worker object for performing CFG-based warnings.
sema::AnalysisBasedWarnings AnalysisWarnings;
threadSafety::BeforeSet *ThreadSafetyDeclCache;

/// An entity for which implicit template instantiation is required.
///
/// The source location associated with the declaration is the first place in
/// the source code where the declaration was "used". It is not necessarily
/// the point of instantiation (which will be either before or after the
/// namespace-scope declaration that triggered this implicit instantiation),
/// However, it is the location that diagnostics should generally refer to,
/// because users will need to know what code triggered the instantiation.
typedef std::pair<ValueDecl *, SourceLocation> PendingImplicitInstantiation;

/// The queue of implicit template instantiations that are required
/// but have not yet been performed.
std::deque<PendingImplicitInstantiation> PendingInstantiations;

/// Queue of implicit template instantiations that cannot be performed
/// eagerly.
SmallVector<PendingImplicitInstantiation, 1> LateParsedInstantiations;

class GlobalEagerInstantiationScope {
public:
  GlobalEagerInstantiationScope(Sema &S, bool Enabled)
      : S(S), Enabled(Enabled) {
    if (!Enabled) return;

    SavedPendingInstantiations.swap(S.PendingInstantiations);
    SavedVTableUses.swap(S.VTableUses);
  }

  void perform() {
    if (Enabled) {
      S.DefineUsedVTables();
      S.PerformPendingInstantiations();
    }
  }

  ~GlobalEagerInstantiationScope() {
    if (!Enabled) return;

    // Restore the set of pending vtables.
    assert(S.VTableUses.empty() &&((S.VTableUses.empty() && "VTableUses should be empty before it is discarded."
) ? static_cast<void> (0) : __assert_fail ("S.VTableUses.empty() && \"VTableUses should be empty before it is discarded.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 8097, __PRETTY_FUNCTION__))
           "VTableUses should be empty before it is discarded.")((S.VTableUses.empty() && "VTableUses should be empty before it is discarded."
) ? static_cast<void> (0) : __assert_fail ("S.VTableUses.empty() && \"VTableUses should be empty before it is discarded.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 8097, __PRETTY_FUNCTION__));
    S.VTableUses.swap(SavedVTableUses);

    // Restore the set of pending implicit instantiations.
    assert(S.PendingInstantiations.empty() &&((S.PendingInstantiations.empty() && "PendingInstantiations should be empty before it is discarded."
) ? static_cast<void> (0) : __assert_fail ("S.PendingInstantiations.empty() && \"PendingInstantiations should be empty before it is discarded.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 8102, __PRETTY_FUNCTION__))
           "PendingInstantiations should be empty before it is discarded.")((S.PendingInstantiations.empty() && "PendingInstantiations should be empty before it is discarded."
) ? static_cast<void> (0) : __assert_fail ("S.PendingInstantiations.empty() && \"PendingInstantiations should be empty before it is discarded.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 8102, __PRETTY_FUNCTION__));
    S.PendingInstantiations.swap(SavedPendingInstantiations);
  }

private:
  Sema &S;
  SmallVector<VTableUse, 16> SavedVTableUses;
  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
  bool Enabled;
};

/// The queue of implicit template instantiations that are required
/// and must be performed within the current local scope.
///
/// This queue is only used for member functions of local classes in
/// templates, which must be instantiated in the same scope as their
/// enclosing function, so that they can reference function-local
/// types, static variables, enumerators, etc.
std::deque<PendingImplicitInstantiation> PendingLocalImplicitInstantiations;

class LocalEagerInstantiationScope {
public:
  LocalEagerInstantiationScope(Sema &S) : S(S) {
    SavedPendingLocalImplicitInstantiations.swap(
        S.PendingLocalImplicitInstantiations);
  }

  void perform() { S.PerformPendingInstantiations(/*LocalOnly=*/true); }

  ~LocalEagerInstantiationScope() {
    assert(S.PendingLocalImplicitInstantiations.empty() &&((S.PendingLocalImplicitInstantiations.empty() && "there shouldn't be any pending local implicit instantiations"
) ? static_cast<void> (0) : __assert_fail ("S.PendingLocalImplicitInstantiations.empty() && \"there shouldn't be any pending local implicit instantiations\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 8133, __PRETTY_FUNCTION__))
           "there shouldn't be any pending local implicit instantiations")((S.PendingLocalImplicitInstantiations.empty() && "there shouldn't be any pending local implicit instantiations"
) ? static_cast<void> (0) : __assert_fail ("S.PendingLocalImplicitInstantiations.empty() && \"there shouldn't be any pending local implicit instantiations\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 8133, __PRETTY_FUNCTION__));
    SavedPendingLocalImplicitInstantiations.swap(
        S.PendingLocalImplicitInstantiations);
  }

private:
  Sema &S;
  std::deque<PendingImplicitInstantiation>
      SavedPendingLocalImplicitInstantiations;
};

/// A helper class for building up ExtParameterInfos.
class ExtParameterInfoBuilder {
  SmallVector<FunctionProtoType::ExtParameterInfo, 16> Infos;
  bool HasInteresting = false;

public:
  /// Set the ExtParameterInfo for the parameter at the given index,
  ///
  void set(unsigned index, FunctionProtoType::ExtParameterInfo info) {
    assert(Infos.size() <= index)((Infos.size() <= index) ? static_cast<void> (0) : __assert_fail
 ("Infos.size() <= index", "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 8153, __PRETTY_FUNCTION__));
    Infos.resize(index);
    Infos.push_back(info);

    if (!HasInteresting)
      HasInteresting = (info != FunctionProtoType::ExtParameterInfo());
  }

  /// Return a pointer (suitable for setting in an ExtProtoInfo) to the
  /// ExtParameterInfo array we've built up.
  const FunctionProtoType::ExtParameterInfo *
  getPointerOrNull(unsigned numParams) {
    if (!HasInteresting) return nullptr;
    Infos.resize(numParams);
    return Infos.data();
  }
};

void PerformPendingInstantiations(bool LocalOnly = false);

TypeSourceInfo *SubstType(TypeSourceInfo *T,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                          SourceLocation Loc, DeclarationName Entity,
                          bool AllowDeducedTST = false);

QualType SubstType(QualType T,
                   const MultiLevelTemplateArgumentList &TemplateArgs,
                   SourceLocation Loc, DeclarationName Entity);

TypeSourceInfo *SubstType(TypeLoc TL,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                          SourceLocation Loc, DeclarationName Entity);

TypeSourceInfo *SubstFunctionDeclType(TypeSourceInfo *T,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                                      SourceLocation Loc,
                                      DeclarationName Entity,
                                      CXXRecordDecl *ThisContext,
                                      Qualifiers ThisTypeQuals);
void SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto,
                        const MultiLevelTemplateArgumentList &Args);
bool SubstExceptionSpec(SourceLocation Loc,
                        FunctionProtoType::ExceptionSpecInfo &ESI,
                        SmallVectorImpl<QualType> &ExceptionStorage,
                        const MultiLevelTemplateArgumentList &Args);
ParmVarDecl *SubstParmVarDecl(ParmVarDecl *D,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                              int indexAdjustment,
                              Optional<unsigned> NumExpansions,
                              bool ExpectParameterPack);
bool SubstParmTypes(SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
                    const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
                    const MultiLevelTemplateArgumentList &TemplateArgs,
                    SmallVectorImpl<QualType> &ParamTypes,
                    SmallVectorImpl<ParmVarDecl *> *OutParams,
                    ExtParameterInfoBuilder &ParamInfos);
ExprResult SubstExpr(Expr *E,
                     const MultiLevelTemplateArgumentList &TemplateArgs);

/// Substitute the given template arguments into a list of
/// expressions, expanding pack expansions if required.
///
/// \param Exprs The list of expressions to substitute into.
///
/// \param IsCall Whether this is some form of call, in which case
/// default arguments will be dropped.
///
/// \param TemplateArgs The set of template arguments to substitute.
///
/// \param Outputs Will receive all of the substituted arguments.
///
/// \returns true if an error occurred, false otherwise.
bool SubstExprs(ArrayRef<Expr *> Exprs, bool IsCall,
                const MultiLevelTemplateArgumentList &TemplateArgs,
                SmallVectorImpl<Expr *> &Outputs);

StmtResult SubstStmt(Stmt *S,
                     const MultiLevelTemplateArgumentList &TemplateArgs);

TemplateParameterList *
SubstTemplateParams(TemplateParameterList *Params, DeclContext *Owner,
                    const MultiLevelTemplateArgumentList &TemplateArgs);

Decl *SubstDecl(Decl *D, DeclContext *Owner,
                const MultiLevelTemplateArgumentList &TemplateArgs);

ExprResult SubstInitializer(Expr *E,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     bool CXXDirectInit);

bool
SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                    CXXRecordDecl *Pattern,
                    const MultiLevelTemplateArgumentList &TemplateArgs);

bool
InstantiateClass(SourceLocation PointOfInstantiation,
                 CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
                 const MultiLevelTemplateArgumentList &TemplateArgs,
                 TemplateSpecializationKind TSK,
                 bool Complain = true);

bool InstantiateEnum(SourceLocation PointOfInstantiation,
                     EnumDecl *Instantiation, EnumDecl *Pattern,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     TemplateSpecializationKind TSK);

bool InstantiateInClassInitializer(
    SourceLocation PointOfInstantiation, FieldDecl *Instantiation,
    FieldDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs);

struct LateInstantiatedAttribute {
  const Attr *TmplAttr;
  LocalInstantiationScope *Scope;
  Decl *NewDecl;

  LateInstantiatedAttribute(const Attr *A, LocalInstantiationScope *S,
                            Decl *D)
    : TmplAttr(A), Scope(S), NewDecl(D)
  { }
};
typedef SmallVector<LateInstantiatedAttribute, 16> LateInstantiatedAttrVec;

void InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
                      const Decl *Pattern, Decl *Inst,
                      LateInstantiatedAttrVec *LateAttrs = nullptr,
                      LocalInstantiationScope *OuterMostScope = nullptr);

void
InstantiateAttrsForDecl(const MultiLevelTemplateArgumentList &TemplateArgs,
                        const Decl *Pattern, Decl *Inst,
                        LateInstantiatedAttrVec *LateAttrs = nullptr,
                        LocalInstantiationScope *OuterMostScope = nullptr);

bool usesPartialOrExplicitSpecialization(
    SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec);

bool
InstantiateClassTemplateSpecialization(SourceLocation PointOfInstantiation,
                         ClassTemplateSpecializationDecl *ClassTemplateSpec,
                         TemplateSpecializationKind TSK,
                         bool Complain = true);

void InstantiateClassMembers(SourceLocation PointOfInstantiation,
                             CXXRecordDecl *Instantiation,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                             TemplateSpecializationKind TSK);

void InstantiateClassTemplateSpecializationMembers(
                                        SourceLocation PointOfInstantiation,
                         ClassTemplateSpecializationDecl *ClassTemplateSpec,
                                              TemplateSpecializationKind TSK);

NestedNameSpecifierLoc
SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS,
                         const MultiLevelTemplateArgumentList &TemplateArgs);

DeclarationNameInfo
SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
                         const MultiLevelTemplateArgumentList &TemplateArgs);
TemplateName
SubstTemplateName(NestedNameSpecifierLoc QualifierLoc, TemplateName Name,
                  SourceLocation Loc,
                  const MultiLevelTemplateArgumentList &TemplateArgs);
bool Subst(const TemplateArgumentLoc *Args, unsigned NumArgs,
           TemplateArgumentListInfo &Result,
           const MultiLevelTemplateArgumentList &TemplateArgs);

void InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
                              FunctionDecl *Function);
FunctionDecl *InstantiateFunctionDeclaration(FunctionTemplateDecl *FTD,
                                             const TemplateArgumentList *Args,
                                             SourceLocation Loc);
void InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
                                   FunctionDecl *Function,
                                   bool Recursive = false,
                                   bool DefinitionRequired = false,
                                   bool AtEndOfTU = false);
VarTemplateSpecializationDecl *BuildVarTemplateInstantiation(
    VarTemplateDecl *VarTemplate, VarDecl *FromVar,
    const TemplateArgumentList &TemplateArgList,
    const TemplateArgumentListInfo &TemplateArgsInfo,
    SmallVectorImpl<TemplateArgument> &Converted,
    SourceLocation PointOfInstantiation, void *InsertPos,
    LateInstantiatedAttrVec *LateAttrs = nullptr,
    LocalInstantiationScope *StartingScope = nullptr);
VarTemplateSpecializationDecl *CompleteVarTemplateSpecializationDecl(
    VarTemplateSpecializationDecl *VarSpec, VarDecl *PatternDecl,
    const MultiLevelTemplateArgumentList &TemplateArgs);
void
BuildVariableInstantiation(VarDecl *NewVar, VarDecl *OldVar,
                           const MultiLevelTemplateArgumentList &TemplateArgs,
                           LateInstantiatedAttrVec *LateAttrs,
                           DeclContext *Owner,
                           LocalInstantiationScope *StartingScope,
                           bool InstantiatingVarTemplate = false,
                           VarTemplateSpecializationDecl *PrevVTSD = nullptr);

VarDecl *getVarTemplateSpecialization(
    VarTemplateDecl *VarTempl, const TemplateArgumentListInfo *TemplateArgs,
    const DeclarationNameInfo &MemberNameInfo, SourceLocation TemplateKWLoc);

void InstantiateVariableInitializer(
    VarDecl *Var, VarDecl *OldVar,
    const MultiLevelTemplateArgumentList &TemplateArgs);
void InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
                                   VarDecl *Var, bool Recursive = false,
                                   bool DefinitionRequired = false,
                                   bool AtEndOfTU = false);

void InstantiateMemInitializers(CXXConstructorDecl *New,
                                const CXXConstructorDecl *Tmpl,
                          const MultiLevelTemplateArgumentList &TemplateArgs);

NamedDecl *FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
                        const MultiLevelTemplateArgumentList &TemplateArgs,
                        bool FindingInstantiatedContext = false);
DeclContext *FindInstantiatedContext(SourceLocation Loc, DeclContext *DC,
                        const MultiLevelTemplateArgumentList &TemplateArgs);

// Objective-C declarations.
enum ObjCContainerKind {
  OCK_None = -1,
  OCK_Interface = 0,
  OCK_Protocol,
  OCK_Category,
  OCK_ClassExtension,
  OCK_Implementation,
  OCK_CategoryImplementation
};
ObjCContainerKind getObjCContainerKind() const;

DeclResult actOnObjCTypeParam(Scope *S,
                              ObjCTypeParamVariance variance,
                              SourceLocation varianceLoc,
                              unsigned index,
                              IdentifierInfo *paramName,
                              SourceLocation paramLoc,
                              SourceLocation colonLoc,
                              ParsedType typeBound);

ObjCTypeParamList *actOnObjCTypeParamList(Scope *S, SourceLocation lAngleLoc,
                                          ArrayRef<Decl *> typeParams,
                                          SourceLocation rAngleLoc);
void popObjCTypeParamList(Scope *S, ObjCTypeParamList *typeParamList);

Decl *ActOnStartClassInterface(
    Scope *S, SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
    SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
    IdentifierInfo *SuperName, SourceLocation SuperLoc,
    ArrayRef<ParsedType> SuperTypeArgs, SourceRange SuperTypeArgsRange,
    Decl *const *ProtoRefs, unsigned NumProtoRefs,
    const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
    const ParsedAttributesView &AttrList);

void ActOnSuperClassOfClassInterface(Scope *S,
                                     SourceLocation AtInterfaceLoc,
                                     ObjCInterfaceDecl *IDecl,
                                     IdentifierInfo *ClassName,
                                     SourceLocation ClassLoc,
                                     IdentifierInfo *SuperName,
                                     SourceLocation SuperLoc,
                                     ArrayRef<ParsedType> SuperTypeArgs,
                                     SourceRange SuperTypeArgsRange);

void ActOnTypedefedProtocols(SmallVectorImpl<Decl *> &ProtocolRefs,
                             SmallVectorImpl<SourceLocation> &ProtocolLocs,
                             IdentifierInfo *SuperName,
                             SourceLocation SuperLoc);

Decl *ActOnCompatibilityAlias(
                  SourceLocation AtCompatibilityAliasLoc,
                  IdentifierInfo *AliasName,  SourceLocation AliasLocation,
                  IdentifierInfo *ClassName, SourceLocation ClassLocation);

bool CheckForwardProtocolDeclarationForCircularDependency(
  IdentifierInfo *PName,
  SourceLocation &PLoc, SourceLocation PrevLoc,
  const ObjCList<ObjCProtocolDecl> &PList);

Decl *ActOnStartProtocolInterface(
    SourceLocation AtProtoInterfaceLoc, IdentifierInfo *ProtocolName,
    SourceLocation ProtocolLoc, Decl *const *ProtoRefNames,
    unsigned NumProtoRefs, const SourceLocation *ProtoLocs,
    SourceLocation EndProtoLoc, const ParsedAttributesView &AttrList);

Decl *ActOnStartCategoryInterface(
    SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
    SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
    IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
    Decl *const *ProtoRefs, unsigned NumProtoRefs,
    const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
    const ParsedAttributesView &AttrList);

Decl *ActOnStartClassImplementation(SourceLocation AtClassImplLoc,
                                    IdentifierInfo *ClassName,
                                    SourceLocation ClassLoc,
                                    IdentifierInfo *SuperClassname,
                                    SourceLocation SuperClassLoc,
                                    const ParsedAttributesView &AttrList);

Decl *ActOnStartCategoryImplementation(SourceLocation AtCatImplLoc,
                                       IdentifierInfo *ClassName,
                                       SourceLocation ClassLoc,
                                       IdentifierInfo *CatName,
                                       SourceLocation CatLoc,
                                       const ParsedAttributesView &AttrList);

DeclGroupPtrTy ActOnFinishObjCImplementation(Decl *ObjCImpDecl,
                                             ArrayRef<Decl *> Decls);

DeclGroupPtrTy ActOnForwardClassDeclaration(SourceLocation Loc,
                 IdentifierInfo **IdentList,
                 SourceLocation *IdentLocs,
                 ArrayRef<ObjCTypeParamList *> TypeParamLists,
                 unsigned NumElts);

DeclGroupPtrTy
ActOnForwardProtocolDeclaration(SourceLocation AtProtoclLoc,
                                ArrayRef<IdentifierLocPair> IdentList,
                                const ParsedAttributesView &attrList);

void FindProtocolDeclaration(bool WarnOnDeclarations, bool ForObjCContainer,
                             ArrayRef<IdentifierLocPair> ProtocolId,
                             SmallVectorImpl<Decl *> &Protocols);

void DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
                                  SourceLocation ProtocolLoc,
                                  IdentifierInfo *TypeArgId,
                                  SourceLocation TypeArgLoc,
                                  bool SelectProtocolFirst = false);

/// Given a list of identifiers (and their locations), resolve the
/// names to either Objective-C protocol qualifiers or type
/// arguments, as appropriate.
void actOnObjCTypeArgsOrProtocolQualifiers(
       Scope *S,
       ParsedType baseType,
       SourceLocation lAngleLoc,
       ArrayRef<IdentifierInfo *> identifiers,
       ArrayRef<SourceLocation> identifierLocs,
       SourceLocation rAngleLoc,
       SourceLocation &typeArgsLAngleLoc,
       SmallVectorImpl<ParsedType> &typeArgs,
       SourceLocation &typeArgsRAngleLoc,
       SourceLocation &protocolLAngleLoc,
       SmallVectorImpl<Decl *> &protocols,
       SourceLocation &protocolRAngleLoc,
       bool warnOnIncompleteProtocols);

/// Build a an Objective-C protocol-qualified 'id' type where no
/// base type was specified.
TypeResult actOnObjCProtocolQualifierType(
             SourceLocation lAngleLoc,
             ArrayRef<Decl *> protocols,
             ArrayRef<SourceLocation> protocolLocs,
             SourceLocation rAngleLoc);

/// Build a specialized and/or protocol-qualified Objective-C type.
TypeResult actOnObjCTypeArgsAndProtocolQualifiers(
             Scope *S,
             SourceLocation Loc,
             ParsedType BaseType,
             SourceLocation TypeArgsLAngleLoc,
             ArrayRef<ParsedType> TypeArgs,
             SourceLocation TypeArgsRAngleLoc,
             SourceLocation ProtocolLAngleLoc,
             ArrayRef<Decl *> Protocols,
             ArrayRef<SourceLocation> ProtocolLocs,
             SourceLocation ProtocolRAngleLoc);

/// Build an Objective-C type parameter type.
QualType BuildObjCTypeParamType(const ObjCTypeParamDecl *Decl,
                                SourceLocation ProtocolLAngleLoc,
                                ArrayRef<ObjCProtocolDecl *> Protocols,
                                ArrayRef<SourceLocation> ProtocolLocs,
                                SourceLocation ProtocolRAngleLoc,
                                bool FailOnError = false);

/// Build an Objective-C object pointer type.
QualType BuildObjCObjectType(QualType BaseType,
                             SourceLocation Loc,
                             SourceLocation TypeArgsLAngleLoc,
                             ArrayRef<TypeSourceInfo *> TypeArgs,
                             SourceLocation TypeArgsRAngleLoc,
                             SourceLocation ProtocolLAngleLoc,
                             ArrayRef<ObjCProtocolDecl *> Protocols,
                             ArrayRef<SourceLocation> ProtocolLocs,
                             SourceLocation ProtocolRAngleLoc,
                             bool FailOnError = false);

/// Ensure attributes are consistent with type.
/// \param [in, out] Attributes The attributes to check; they will
/// be modified to be consistent with \p PropertyTy.
void CheckObjCPropertyAttributes(Decl *PropertyPtrTy,
                                 SourceLocation Loc,
                                 unsigned &Attributes,
                                 bool propertyInPrimaryClass);

/// Process the specified property declaration and create decls for the
/// setters and getters as needed.
/// \param property The property declaration being processed
void ProcessPropertyDecl(ObjCPropertyDecl *property);


void DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
                              ObjCPropertyDecl *SuperProperty,
                              const IdentifierInfo *Name,
                              bool OverridingProtocolProperty);

void DiagnoseClassExtensionDupMethods(ObjCCategoryDecl *CAT,
                                      ObjCInterfaceDecl *ID);

Decl *ActOnAtEnd(Scope *S, SourceRange AtEnd,
                 ArrayRef<Decl *> allMethods = None,
                 ArrayRef<DeclGroupPtrTy> allTUVars = None);

Decl *ActOnProperty(Scope *S, SourceLocation AtLoc,
                    SourceLocation LParenLoc,
                    FieldDeclarator &FD, ObjCDeclSpec &ODS,
                    Selector GetterSel, Selector SetterSel,
                    tok::ObjCKeywordKind MethodImplKind,
                    DeclContext *lexicalDC = nullptr);

Decl *ActOnPropertyImplDecl(Scope *S,
                            SourceLocation AtLoc,
                            SourceLocation PropertyLoc,
                            bool ImplKind,
                            IdentifierInfo *PropertyId,
                            IdentifierInfo *PropertyIvar,
                            SourceLocation PropertyIvarLoc,
                            ObjCPropertyQueryKind QueryKind);

enum ObjCSpecialMethodKind {
  OSMK_None,
  OSMK_Alloc,
  OSMK_New,
  OSMK_Copy,
  OSMK_RetainingInit,
  OSMK_NonRetainingInit
};

struct ObjCArgInfo {
  IdentifierInfo *Name;
  SourceLocation NameLoc;
  // The Type is null if no type was specified, and the DeclSpec is invalid
  // in this case.
  ParsedType Type;
  ObjCDeclSpec DeclSpec;

  /// ArgAttrs - Attribute list for this argument.
  ParsedAttributesView ArgAttrs;
};

Decl *ActOnMethodDeclaration(
    Scope *S,
    SourceLocation BeginLoc, // location of the + or -.
    SourceLocation EndLoc,   // location of the ; or {.
    tok::TokenKind MethodType, ObjCDeclSpec &ReturnQT, ParsedType ReturnType,
    ArrayRef<SourceLocation> SelectorLocs, Selector Sel,
    // optional arguments. The number of types/arguments is obtained
    // from the Sel.getNumArgs().
    ObjCArgInfo *ArgInfo, DeclaratorChunk::ParamInfo *CParamInfo,
    unsigned CNumArgs, // c-style args
    const ParsedAttributesView &AttrList, tok::ObjCKeywordKind MethodImplKind,
    bool isVariadic, bool MethodDefinition);

ObjCMethodDecl *LookupMethodInQualifiedType(Selector Sel,
                                            const ObjCObjectPointerType *OPT,
                                            bool IsInstance);
ObjCMethodDecl *LookupMethodInObjectType(Selector Sel, QualType Ty,
                                         bool IsInstance);

bool CheckARCMethodDecl(ObjCMethodDecl *method);
bool inferObjCARCLifetime(ValueDecl *decl);

ExprResult
HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
                          Expr *BaseExpr,
                          SourceLocation OpLoc,
                          DeclarationName MemberName,
                          SourceLocation MemberLoc,
                          SourceLocation SuperLoc, QualType SuperType,
                          bool Super);

ExprResult
ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
                          IdentifierInfo &propertyName,
                          SourceLocation receiverNameLoc,
                          SourceLocation propertyNameLoc);

ObjCMethodDecl *tryCaptureObjCSelf(SourceLocation Loc);

/// Describes the kind of message expression indicated by a message
/// send that starts with an identifier.
enum ObjCMessageKind {
  /// The message is sent to 'super'.
  ObjCSuperMessage,
  /// The message is an instance message.
  ObjCInstanceMessage,
  /// The message is a class message, and the identifier is a type
  /// name.
  ObjCClassMessage
};

ObjCMessageKind getObjCMessageKind(Scope *S,
                                   IdentifierInfo *Name,
                                   SourceLocation NameLoc,
                                   bool IsSuper,
                                   bool HasTrailingDot,
                                   ParsedType &ReceiverType);

ExprResult ActOnSuperMessage(Scope *S, SourceLocation SuperLoc,
                             Selector Sel,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args);

ExprResult BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
                             QualType ReceiverType,
                             SourceLocation SuperLoc,
                             Selector Sel,
                             ObjCMethodDecl *Method,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args,
                             bool isImplicit = false);

ExprResult BuildClassMessageImplicit(QualType ReceiverType,
                                     bool isSuperReceiver,
                                     SourceLocation Loc,
                                     Selector Sel,
                                     ObjCMethodDecl *Method,
                                     MultiExprArg Args);

ExprResult ActOnClassMessage(Scope *S,
                             ParsedType Receiver,
                             Selector Sel,
                             SourceLocation LBracLoc,
                             ArrayRef<SourceLocation> SelectorLocs,
                             SourceLocation RBracLoc,
                             MultiExprArg Args);

ExprResult BuildInstanceMessage(Expr *Receiver,
                                QualType ReceiverType,
                                SourceLocation SuperLoc,
                                Selector Sel,
                                ObjCMethodDecl *Method,
                                SourceLocation LBracLoc,
                                ArrayRef<SourceLocation> SelectorLocs,
                                SourceLocation RBracLoc,
                                MultiExprArg Args,
                                bool isImplicit = false);

ExprResult BuildInstanceMessageImplicit(Expr *Receiver,
                                        QualType ReceiverType,
                                        SourceLocation Loc,
                                        Selector Sel,
                                        ObjCMethodDecl *Method,
                                        MultiExprArg Args);

ExprResult ActOnInstanceMessage(Scope *S,
                                Expr *Receiver,
                                Selector Sel,
                                SourceLocation LBracLoc,
                                ArrayRef<SourceLocation> SelectorLocs,
                                SourceLocation RBracLoc,
                                MultiExprArg Args);

ExprResult BuildObjCBridgedCast(SourceLocation LParenLoc,
                                ObjCBridgeCastKind Kind,
                                SourceLocation BridgeKeywordLoc,
                                TypeSourceInfo *TSInfo,
                                Expr *SubExpr);

ExprResult ActOnObjCBridgedCast(Scope *S,
                                SourceLocation LParenLoc,
                                ObjCBridgeCastKind Kind,
                                SourceLocation BridgeKeywordLoc,
                                ParsedType Type,
                                SourceLocation RParenLoc,
                                Expr *SubExpr);

void CheckTollFreeBridgeCast(QualType castType, Expr *castExpr);

void CheckObjCBridgeRelatedCast(QualType castType, Expr *castExpr);

bool CheckTollFreeBridgeStaticCast(QualType castType, Expr *castExpr,
                                   CastKind &Kind);

bool checkObjCBridgeRelatedComponents(SourceLocation Loc,
                                      QualType DestType, QualType SrcType,
                                      ObjCInterfaceDecl *&RelatedClass,
                                      ObjCMethodDecl *&ClassMethod,
                                      ObjCMethodDecl *&InstanceMethod,
                                      TypedefNameDecl *&TDNDecl,
                                      bool CfToNs, bool Diagnose = true);

bool CheckObjCBridgeRelatedConversions(SourceLocation Loc,
                                       QualType DestType, QualType SrcType,
                                       Expr *&SrcExpr, bool Diagnose = true);

bool ConversionToObjCStringLiteralCheck(QualType DstType, Expr *&SrcExpr,
                                        bool Diagnose = true);

bool checkInitMethod(ObjCMethodDecl *method, QualType receiverTypeIfCall);

/// Check whether the given new method is a valid override of the
/// given overridden method, and set any properties that should be inherited.
void CheckObjCMethodOverride(ObjCMethodDecl *NewMethod,
                             const ObjCMethodDecl *Overridden);

/// Describes the compatibility of a result type with its method.
enum ResultTypeCompatibilityKind {
  RTC_Compatible,
  RTC_Incompatible,
  RTC_Unknown
};

void CheckObjCMethodOverrides(ObjCMethodDecl *ObjCMethod,
                              ObjCInterfaceDecl *CurrentClass,
                              ResultTypeCompatibilityKind RTC);

enum PragmaOptionsAlignKind {
  POAK_Native,  // #pragma options align=native
  POAK_Natural, // #pragma options align=natural
  POAK_Packed,  // #pragma options align=packed
  POAK_Power,   // #pragma options align=power
  POAK_Mac68k,  // #pragma options align=mac68k
  POAK_Reset    // #pragma options align=reset
};

/// ActOnPragmaClangSection - Called on well formed \#pragma clang section
void ActOnPragmaClangSection(SourceLocation PragmaLoc,
                             PragmaClangSectionAction Action,
                             PragmaClangSectionKind SecKind, StringRef SecName);

/// ActOnPragmaOptionsAlign - Called on well formed \#pragma options align.
void ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
                             SourceLocation PragmaLoc);

/// ActOnPragmaPack - Called on well formed \#pragma pack(...).
void ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
                     StringRef SlotLabel, Expr *Alignment);

enum class PragmaPackDiagnoseKind {
  NonDefaultStateAtInclude,
  ChangedStateAtExit
};

void DiagnoseNonDefaultPragmaPack(PragmaPackDiagnoseKind Kind,
                                  SourceLocation IncludeLoc);
void DiagnoseUnterminatedPragmaPack();

/// ActOnPragmaMSStruct - Called on well formed \#pragma ms_struct [on|off].
void ActOnPragmaMSStruct(PragmaMSStructKind Kind);

/// ActOnPragmaMSComment - Called on well formed
/// \#pragma comment(kind, "arg").
void ActOnPragmaMSComment(SourceLocation CommentLoc, PragmaMSCommentKind Kind,
                          StringRef Arg);

/// ActOnPragmaMSPointersToMembers - called on well formed \#pragma
/// pointers_to_members(representation method[, general purpose
/// representation]).
void ActOnPragmaMSPointersToMembers(
    LangOptions::PragmaMSPointersToMembersKind Kind,
    SourceLocation PragmaLoc);

/// Called on well formed \#pragma vtordisp().
void ActOnPragmaMSVtorDisp(PragmaMsStackAction Action,
                           SourceLocation PragmaLoc,
                           MSVtorDispAttr::Mode Value);

enum PragmaSectionKind {
  PSK_DataSeg,
  PSK_BSSSeg,
  PSK_ConstSeg,
  PSK_CodeSeg,
};

bool UnifySection(StringRef SectionName,
                  int SectionFlags,
                  DeclaratorDecl *TheDecl);
bool UnifySection(StringRef SectionName,
                  int SectionFlags,
                  SourceLocation PragmaSectionLocation);

/// Called on well formed \#pragma bss_seg/data_seg/const_seg/code_seg.
void ActOnPragmaMSSeg(SourceLocation PragmaLocation,
                      PragmaMsStackAction Action,
                      llvm::StringRef StackSlotLabel,
                      StringLiteral *SegmentName,
                      llvm::StringRef PragmaName);

/// Called on well formed \#pragma section().
void ActOnPragmaMSSection(SourceLocation PragmaLocation,
                          int SectionFlags, StringLiteral *SegmentName);

/// Called on well-formed \#pragma init_seg().
void ActOnPragmaMSInitSeg(SourceLocation PragmaLocation,
                          StringLiteral *SegmentName);

/// Called on #pragma clang __debug dump II
void ActOnPragmaDump(Scope *S, SourceLocation Loc, IdentifierInfo *II);

/// ActOnPragmaDetectMismatch - Call on well-formed \#pragma detect_mismatch
void ActOnPragmaDetectMismatch(SourceLocation Loc, StringRef Name,
                               StringRef Value);

/// ActOnPragmaUnused - Called on well-formed '\#pragma unused'.
void ActOnPragmaUnused(const Token &Identifier,
                       Scope *curScope,
                       SourceLocation PragmaLoc);

/// ActOnPragmaVisibility - Called on well formed \#pragma GCC visibility... .
void ActOnPragmaVisibility(const IdentifierInfo* VisType,
                           SourceLocation PragmaLoc);

NamedDecl *DeclClonePragmaWeak(NamedDecl *ND, IdentifierInfo *II,
                               SourceLocation Loc);
void DeclApplyPragmaWeak(Scope *S, NamedDecl *ND, WeakInfo &W);

/// ActOnPragmaWeakID - Called on well formed \#pragma weak ident.
void ActOnPragmaWeakID(IdentifierInfo* WeakName,
                       SourceLocation PragmaLoc,
                       SourceLocation WeakNameLoc);

/// ActOnPragmaRedefineExtname - Called on well formed
/// \#pragma redefine_extname oldname newname.
void ActOnPragmaRedefineExtname(IdentifierInfo* WeakName,
                                IdentifierInfo* AliasName,
                                SourceLocation PragmaLoc,
                                SourceLocation WeakNameLoc,
                                SourceLocation AliasNameLoc);

/// ActOnPragmaWeakAlias - Called on well formed \#pragma weak ident = ident.
void ActOnPragmaWeakAlias(IdentifierInfo* WeakName,
                          IdentifierInfo* AliasName,
                          SourceLocation PragmaLoc,
                          SourceLocation WeakNameLoc,
                          SourceLocation AliasNameLoc);

/// ActOnPragmaFPContract - Called on well formed
/// \#pragma {STDC,OPENCL} FP_CONTRACT and
/// \#pragma clang fp contract
void ActOnPragmaFPContract(LangOptions::FPContractModeKind FPC);

/// ActOnPragmaFenvAccess - Called on well formed
/// \#pragma STDC FENV_ACCESS
void ActOnPragmaFEnvAccess(LangOptions::FEnvAccessModeKind FPC);

/// AddAlignmentAttributesForRecord - Adds any needed alignment attributes to
/// a the record decl, to handle '\#pragma pack' and '\#pragma options align'.
void AddAlignmentAttributesForRecord(RecordDecl *RD);

/// AddMsStructLayoutForRecord - Adds ms_struct layout attribute to record.
void AddMsStructLayoutForRecord(RecordDecl *RD);

/// FreePackedContext - Deallocate and null out PackContext.
void FreePackedContext();

/// PushNamespaceVisibilityAttr - Note that we've entered a
/// namespace with a visibility attribute.
void PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
                                 SourceLocation Loc);

/// AddPushedVisibilityAttribute - If '\#pragma GCC visibility' was used,
/// add an appropriate visibility attribute.
void AddPushedVisibilityAttribute(Decl *RD);

/// PopPragmaVisibility - Pop the top element of the visibility stack; used
/// for '\#pragma GCC visibility' and visibility attributes on namespaces.
void PopPragmaVisibility(bool IsNamespaceEnd, SourceLocation EndLoc);

/// FreeVisContext - Deallocate and null out VisContext.
void FreeVisContext();

/// AddCFAuditedAttribute - Check whether we're currently within
/// '\#pragma clang arc_cf_code_audited' and, if so, consider adding
/// the appropriate attribute.
void AddCFAuditedAttribute(Decl *D);

void ActOnPragmaAttributeAttribute(ParsedAttr &Attribute,
                                   SourceLocation PragmaLoc,
                                   attr::ParsedSubjectMatchRuleSet Rules);
void ActOnPragmaAttributeEmptyPush(SourceLocation PragmaLoc,
                                   const IdentifierInfo *Namespace);

/// Called on well-formed '\#pragma clang attribute pop'.
void ActOnPragmaAttributePop(SourceLocation PragmaLoc,
                             const IdentifierInfo *Namespace);

/// Adds the attributes that have been specified using the
/// '\#pragma clang attribute push' directives to the given declaration.
void AddPragmaAttributes(Scope *S, Decl *D);

void DiagnoseUnterminatedPragmaAttribute();

/// Called on well formed \#pragma clang optimize.
void ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc);

/// Get the location for the currently active "\#pragma clang optimize
/// off". If this location is invalid, then the state of the pragma is "on".
SourceLocation getOptimizeOffPragmaLocation() const {
  return OptimizeOffPragmaLocation;
}

/// Only called on function definitions; if there is a pragma in scope
/// with the effect of a range-based optnone, consider marking the function
/// with attribute optnone.
void AddRangeBasedOptnone(FunctionDecl *FD);

/// Adds the 'optnone' attribute to the function declaration if there
/// are no conflicts; Loc represents the location causing the 'optnone'
/// attribute to be added (usually because of a pragma).
void AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD, SourceLocation Loc);

/// AddAlignedAttr - Adds an aligned attribute to a particular declaration.
void AddAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
                    bool IsPackExpansion);
void AddAlignedAttr(Decl *D, const AttributeCommonInfo &CI, TypeSourceInfo *T,
                    bool IsPackExpansion);

/// AddAssumeAlignedAttr - Adds an assume_aligned attribute to a particular
/// declaration.
void AddAssumeAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
                          Expr *OE);

/// AddAllocAlignAttr - Adds an alloc_align attribute to a particular
/// declaration.
void AddAllocAlignAttr(Decl *D, const AttributeCommonInfo &CI,
                       Expr *ParamExpr);

/// AddAlignValueAttr - Adds an align_value attribute to a particular
/// declaration.
void AddAlignValueAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E);

/// AddLaunchBoundsAttr - Adds a launch_bounds attribute to a particular
/// declaration.
void AddLaunchBoundsAttr(Decl *D, const AttributeCommonInfo &CI,
                         Expr *MaxThreads, Expr *MinBlocks);

/// AddModeAttr - Adds a mode attribute to a particular declaration.
void AddModeAttr(Decl *D, const AttributeCommonInfo &CI, IdentifierInfo *Name,
                 bool InInstantiation = false);

void AddParameterABIAttr(Decl *D, const AttributeCommonInfo &CI,
                         ParameterABI ABI);

enum class RetainOwnershipKind {NS, CF, OS};
void AddXConsumedAttr(Decl *D, const AttributeCommonInfo &CI,
                      RetainOwnershipKind K, bool IsTemplateInstantiation);

/// addAMDGPUFlatWorkGroupSizeAttr - Adds an amdgpu_flat_work_group_size
/// attribute to a particular declaration.
void addAMDGPUFlatWorkGroupSizeAttr(Decl *D, const AttributeCommonInfo &CI,
                                    Expr *Min, Expr *Max);

/// addAMDGPUWavePersEUAttr - Adds an amdgpu_waves_per_eu attribute to a
/// particular declaration.
void addAMDGPUWavesPerEUAttr(Decl *D, const AttributeCommonInfo &CI,
                             Expr *Min, Expr *Max);

bool checkNSReturnsRetainedReturnType(SourceLocation loc, QualType type);

//===--------------------------------------------------------------------===//
// C++ Coroutines TS
//
bool ActOnCoroutineBodyStart(Scope *S, SourceLocation KwLoc,
                             StringRef Keyword);
ExprResult ActOnCoawaitExpr(Scope *S, SourceLocation KwLoc, Expr *E);
ExprResult ActOnCoyieldExpr(Scope *S, SourceLocation KwLoc, Expr *E);
StmtResult ActOnCoreturnStmt(Scope *S, SourceLocation KwLoc, Expr *E);

ExprResult BuildResolvedCoawaitExpr(SourceLocation KwLoc, Expr *E,
                                    bool IsImplicit = false);
ExprResult BuildUnresolvedCoawaitExpr(SourceLocation KwLoc, Expr *E,
                                      UnresolvedLookupExpr* Lookup);
ExprResult BuildCoyieldExpr(SourceLocation KwLoc, Expr *E);
StmtResult BuildCoreturnStmt(SourceLocation KwLoc, Expr *E,
                             bool IsImplicit = false);
StmtResult BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs);
bool buildCoroutineParameterMoves(SourceLocation Loc);
VarDecl *buildCoroutinePromise(SourceLocation Loc);
void CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body);
ClassTemplateDecl *lookupCoroutineTraits(SourceLocation KwLoc,
                                         SourceLocation FuncLoc);

//===--------------------------------------------------------------------===//
// OpenCL extensions.
//
9047private:
std::string CurrOpenCLExtension;
/// Extensions required by an OpenCL type.
llvm::DenseMap<const Type*, std::set<std::string>> OpenCLTypeExtMap;
/// Extensions required by an OpenCL declaration.
llvm::DenseMap<const Decl*, std::set<std::string>> OpenCLDeclExtMap;
9053public:
llvm::StringRef getCurrentOpenCLExtension() const {
  return CurrOpenCLExtension;
}

/// Check if a function declaration \p FD associates with any
/// extensions present in OpenCLDeclExtMap and if so return the
/// extension(s) name(s).
std::string getOpenCLExtensionsFromDeclExtMap(FunctionDecl *FD);

/// Check if a function type \p FT associates with any
/// extensions present in OpenCLTypeExtMap and if so return the
/// extension(s) name(s).
std::string getOpenCLExtensionsFromTypeExtMap(FunctionType *FT);

/// Find an extension in an appropriate extension map and return its name
template<typename T, typename MapT>
std::string getOpenCLExtensionsFromExtMap(T* FT, MapT &Map);

void setCurrentOpenCLExtension(llvm::StringRef Ext) {
  CurrOpenCLExtension = Ext;
}

/// Set OpenCL extensions for a type which can only be used when these
/// OpenCL extensions are enabled. If \p Exts is empty, do nothing.
/// \param Exts A space separated list of OpenCL extensions.
void setOpenCLExtensionForType(QualType T, llvm::StringRef Exts);

/// Set OpenCL extensions for a declaration which can only be
/// used when these OpenCL extensions are enabled. If \p Exts is empty, do
/// nothing.
/// \param Exts A space separated list of OpenCL extensions.
void setOpenCLExtensionForDecl(Decl *FD, llvm::StringRef Exts);

/// Set current OpenCL extensions for a type which can only be used
/// when these OpenCL extensions are enabled. If current OpenCL extension is
/// empty, do nothing.
void setCurrentOpenCLExtensionForType(QualType T);

/// Set current OpenCL extensions for a declaration which
/// can only be used when these OpenCL extensions are enabled. If current
/// OpenCL extension is empty, do nothing.
void setCurrentOpenCLExtensionForDecl(Decl *FD);

bool isOpenCLDisabledDecl(Decl *FD);

/// Check if type \p T corresponding to declaration specifier \p DS
/// is disabled due to required OpenCL extensions being disabled. If so,
/// emit diagnostics.
/// \return true if type is disabled.
bool checkOpenCLDisabledTypeDeclSpec(const DeclSpec &DS, QualType T);

/// Check if declaration \p D used by expression \p E
/// is disabled due to required OpenCL extensions being disabled. If so,
/// emit diagnostics.
/// \return true if type is disabled.
bool checkOpenCLDisabledDecl(const NamedDecl &D, const Expr &E);

//===--------------------------------------------------------------------===//
// OpenMP directives and clauses.
//
9114private:
void *VarDataSharingAttributesStack;
/// Number of nested '#pragma omp declare target' directives.
unsigned DeclareTargetNestingLevel = 0;
/// Initialization of data-sharing attributes stack.
void InitDataSharingAttributesStack();
void DestroyDataSharingAttributesStack();
ExprResult
VerifyPositiveIntegerConstantInClause(Expr *Op, OpenMPClauseKind CKind,
                                      bool StrictlyPositive = true);
/// Returns OpenMP nesting level for current directive.
unsigned getOpenMPNestingLevel() const;

/// Adjusts the function scopes index for the target-based regions.
void adjustOpenMPTargetScopeIndex(unsigned &FunctionScopesIndex,
                                  unsigned Level) const;

/// Returns the number of scopes associated with the construct on the given
/// OpenMP level.
int getNumberOfConstructScopes(unsigned Level) const;

/// Push new OpenMP function region for non-capturing function.
void pushOpenMPFunctionRegion();

/// Pop OpenMP function region for non-capturing function.
void popOpenMPFunctionRegion(const sema::FunctionScopeInfo *OldFSI);

/// Check whether we're allowed to call Callee from the current function.
void checkOpenMPDeviceFunction(SourceLocation Loc, FunctionDecl *Callee,
                               bool CheckForDelayedContext = true);

/// Check whether we're allowed to call Callee from the current function.
void checkOpenMPHostFunction(SourceLocation Loc, FunctionDecl *Callee,
                             bool CheckCaller = true);

/// Check if the expression is allowed to be used in expressions for the
/// OpenMP devices.
void checkOpenMPDeviceExpr(const Expr *E);

/// Finishes analysis of the deferred functions calls that may be declared as
/// host/nohost during device/host compilation.
void finalizeOpenMPDelayedAnalysis();

/// Checks if a type or a declaration is disabled due to the owning extension
/// being disabled, and emits diagnostic messages if it is disabled.
/// \param D type or declaration to be checked.
/// \param DiagLoc source location for the diagnostic message.
/// \param DiagInfo information to be emitted for the diagnostic message.
/// \param SrcRange source range of the declaration.
/// \param Map maps type or declaration to the extensions.
/// \param Selector selects diagnostic message: 0 for type and 1 for
///        declaration.
/// \return true if the type or declaration is disabled.
template <typename T, typename DiagLocT, typename DiagInfoT, typename MapT>
bool checkOpenCLDisabledTypeOrDecl(T D, DiagLocT DiagLoc, DiagInfoT DiagInfo,
                                   MapT &Map, unsigned Selector = 0,
                                   SourceRange SrcRange = SourceRange());

/// Marks all the functions that might be required for the currently active
/// OpenMP context.
void markOpenMPDeclareVariantFuncsReferenced(SourceLocation Loc,
                                             FunctionDecl *Func,
                                             bool MightBeOdrUse);

9178public:
/// Struct to store the context selectors info for declare variant directive.
struct OpenMPDeclareVariantCtsSelectorData {
  OMPDeclareVariantAttr::CtxSelectorSetType CtxSet =
      OMPDeclareVariantAttr::CtxSetUnknown;
  OMPDeclareVariantAttr::CtxSelectorType Ctx =
      OMPDeclareVariantAttr::CtxUnknown;
  MutableArrayRef<StringRef> ImplVendors;
  ExprResult CtxScore;
  explicit OpenMPDeclareVariantCtsSelectorData() = default;
  explicit OpenMPDeclareVariantCtsSelectorData(
      OMPDeclareVariantAttr::CtxSelectorSetType CtxSet,
      OMPDeclareVariantAttr::CtxSelectorType Ctx,
      MutableArrayRef<StringRef> ImplVendors, ExprResult CtxScore)
      : CtxSet(CtxSet), Ctx(Ctx), ImplVendors(ImplVendors),
        CtxScore(CtxScore) {}
};

/// Checks if the variant/multiversion functions are compatible.
bool areMultiversionVariantFunctionsCompatible(
    const FunctionDecl *OldFD, const FunctionDecl *NewFD,
    const PartialDiagnostic &NoProtoDiagID,
    const PartialDiagnosticAt &NoteCausedDiagIDAt,
    const PartialDiagnosticAt &NoSupportDiagIDAt,
    const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
    bool ConstexprSupported, bool CLinkageMayDiffer);

/// Function tries to capture lambda's captured variables in the OpenMP region
/// before the original lambda is captured.
void tryCaptureOpenMPLambdas(ValueDecl *V);

/// Return true if the provided declaration \a VD should be captured by
/// reference.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
/// \param OpenMPCaptureLevel Capture level within an OpenMP construct.
bool isOpenMPCapturedByRef(const ValueDecl *D, unsigned Level,
                           unsigned OpenMPCaptureLevel) const;

/// Check if the specified variable is used in one of the private
/// clauses (private, firstprivate, lastprivate, reduction etc.) in OpenMP
/// constructs.
VarDecl *isOpenMPCapturedDecl(ValueDecl *D, bool CheckScopeInfo = false,
                              unsigned StopAt = 0);
ExprResult getOpenMPCapturedExpr(VarDecl *Capture, ExprValueKind VK,
                                 ExprObjectKind OK, SourceLocation Loc);

/// If the current region is a loop-based region, mark the start of the loop
/// construct.
void startOpenMPLoop();

/// If the current region is a range loop-based region, mark the start of the
/// loop construct.
void startOpenMPCXXRangeFor();

/// Check if the specified variable is used in 'private' clause.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
bool isOpenMPPrivateDecl(const ValueDecl *D, unsigned Level) const;

/// Sets OpenMP capture kind (OMPC_private, OMPC_firstprivate, OMPC_map etc.)
/// for \p FD based on DSA for the provided corresponding captured declaration
/// \p D.
void setOpenMPCaptureKind(FieldDecl *FD, const ValueDecl *D, unsigned Level);

/// Check if the specified variable is captured  by 'target' directive.
/// \param Level Relative level of nested OpenMP construct for that the check
/// is performed.
bool isOpenMPTargetCapturedDecl(const ValueDecl *D, unsigned Level) const;

ExprResult PerformOpenMPImplicitIntegerConversion(SourceLocation OpLoc,
                                                  Expr *Op);
/// Called on start of new data sharing attribute block.
void StartOpenMPDSABlock(OpenMPDirectiveKind K,
                         const DeclarationNameInfo &DirName, Scope *CurScope,
                         SourceLocation Loc);
/// Start analysis of clauses.
void StartOpenMPClause(OpenMPClauseKind K);
/// End analysis of clauses.
void EndOpenMPClause();
/// Called on end of data sharing attribute block.
void EndOpenMPDSABlock(Stmt *CurDirective);

/// Check if the current region is an OpenMP loop region and if it is,
/// mark loop control variable, used in \p Init for loop initialization, as
/// private by default.
/// \param Init First part of the for loop.
void ActOnOpenMPLoopInitialization(SourceLocation ForLoc, Stmt *Init);

// OpenMP directives and clauses.
/// Called on correct id-expression from the '#pragma omp
/// threadprivate'.
ExprResult ActOnOpenMPIdExpression(Scope *CurScope, CXXScopeSpec &ScopeSpec,
                                   const DeclarationNameInfo &Id,
                                   OpenMPDirectiveKind Kind);
/// Called on well-formed '#pragma omp threadprivate'.
DeclGroupPtrTy ActOnOpenMPThreadprivateDirective(
                                   SourceLocation Loc,
                                   ArrayRef<Expr *> VarList);
/// Builds a new OpenMPThreadPrivateDecl and checks its correctness.
OMPThreadPrivateDecl *CheckOMPThreadPrivateDecl(SourceLocation Loc,
                                                ArrayRef<Expr *> VarList);
/// Called on well-formed '#pragma omp allocate'.
DeclGroupPtrTy ActOnOpenMPAllocateDirective(SourceLocation Loc,
                                            ArrayRef<Expr *> VarList,
                                            ArrayRef<OMPClause *> Clauses,
                                            DeclContext *Owner = nullptr);
/// Called on well-formed '#pragma omp requires'.
DeclGroupPtrTy ActOnOpenMPRequiresDirective(SourceLocation Loc,
                                            ArrayRef<OMPClause *> ClauseList);
/// Check restrictions on Requires directive
OMPRequiresDecl *CheckOMPRequiresDecl(SourceLocation Loc,
                                      ArrayRef<OMPClause *> Clauses);
/// Check if the specified type is allowed to be used in 'omp declare
/// reduction' construct.
QualType ActOnOpenMPDeclareReductionType(SourceLocation TyLoc,
                                         TypeResult ParsedType);
/// Called on start of '#pragma omp declare reduction'.
DeclGroupPtrTy ActOnOpenMPDeclareReductionDirectiveStart(
    Scope *S, DeclContext *DC, DeclarationName Name,
    ArrayRef<std::pair<QualType, SourceLocation>> ReductionTypes,
    AccessSpecifier AS, Decl *PrevDeclInScope = nullptr);
/// Initialize declare reduction construct initializer.
void ActOnOpenMPDeclareReductionCombinerStart(Scope *S, Decl *D);
/// Finish current declare reduction construct initializer.
void ActOnOpenMPDeclareReductionCombinerEnd(Decl *D, Expr *Combiner);
/// Initialize declare reduction construct initializer.
/// \return omp_priv variable.
VarDecl *ActOnOpenMPDeclareReductionInitializerStart(Scope *S, Decl *D);
/// Finish current declare reduction construct initializer.
void ActOnOpenMPDeclareReductionInitializerEnd(Decl *D, Expr *Initializer,
                                               VarDecl *OmpPrivParm);
/// Called at the end of '#pragma omp declare reduction'.
DeclGroupPtrTy ActOnOpenMPDeclareReductionDirectiveEnd(
    Scope *S, DeclGroupPtrTy DeclReductions, bool IsValid);

/// Check variable declaration in 'omp declare mapper' construct.
TypeResult ActOnOpenMPDeclareMapperVarDecl(Scope *S, Declarator &D);
/// Check if the specified type is allowed to be used in 'omp declare
/// mapper' construct.
QualType ActOnOpenMPDeclareMapperType(SourceLocation TyLoc,
                                      TypeResult ParsedType);
/// Called on start of '#pragma omp declare mapper'.
OMPDeclareMapperDecl *ActOnOpenMPDeclareMapperDirectiveStart(
    Scope *S, DeclContext *DC, DeclarationName Name, QualType MapperType,
    SourceLocation StartLoc, DeclarationName VN, AccessSpecifier AS,
    Decl *PrevDeclInScope = nullptr);
/// Build the mapper variable of '#pragma omp declare mapper'.
void ActOnOpenMPDeclareMapperDirectiveVarDecl(OMPDeclareMapperDecl *DMD,
                                              Scope *S, QualType MapperType,
                                              SourceLocation StartLoc,
                                              DeclarationName VN);
/// Called at the end of '#pragma omp declare mapper'.
DeclGroupPtrTy
ActOnOpenMPDeclareMapperDirectiveEnd(OMPDeclareMapperDecl *D, Scope *S,
                                     ArrayRef<OMPClause *> ClauseList);

/// Called on the start of target region i.e. '#pragma omp declare target'.
bool ActOnStartOpenMPDeclareTargetDirective(SourceLocation Loc);
/// Called at the end of target region i.e. '#pragme omp end declare target'.
void ActOnFinishOpenMPDeclareTargetDirective();
/// Searches for the provided declaration name for OpenMP declare target
/// directive.
NamedDecl *
lookupOpenMPDeclareTargetName(Scope *CurScope, CXXScopeSpec &ScopeSpec,
                              const DeclarationNameInfo &Id,
                              NamedDeclSetType &SameDirectiveDecls);
/// Called on correct id-expression from the '#pragma omp declare target'.
void ActOnOpenMPDeclareTargetName(NamedDecl *ND, SourceLocation Loc,
                                  OMPDeclareTargetDeclAttr::MapTypeTy MT,
                                  OMPDeclareTargetDeclAttr::DevTypeTy DT);
/// Check declaration inside target region.
void
checkDeclIsAllowedInOpenMPTarget(Expr *E, Decl *D,
                                 SourceLocation IdLoc = SourceLocation());
/// Return true inside OpenMP declare target region.
bool isInOpenMPDeclareTargetContext() const {
  return DeclareTargetNestingLevel > 0;
}
/// Return true inside OpenMP target region.
bool isInOpenMPTargetExecutionDirective() const;

/// Return the number of captured regions created for an OpenMP directive.
static int getOpenMPCaptureLevels(OpenMPDirectiveKind Kind);

/// Initialization of captured region for OpenMP region.
void ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope);
/// End of OpenMP region.
///
/// \param S Statement associated with the current OpenMP region.
/// \param Clauses List of clauses for the current OpenMP region.
///
/// \returns Statement for finished OpenMP region.
StmtResult ActOnOpenMPRegionEnd(StmtResult S, ArrayRef<OMPClause *> Clauses);
StmtResult ActOnOpenMPExecutableDirective(
    OpenMPDirectiveKind Kind, const DeclarationNameInfo &DirName,
    OpenMPDirectiveKind CancelRegion, ArrayRef<OMPClause *> Clauses,
    Stmt *AStmt, SourceLocation StartLoc, SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel' after parsing
/// of the  associated statement.
StmtResult ActOnOpenMPParallelDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt,
                                        SourceLocation StartLoc,
                                        SourceLocation EndLoc);
using VarsWithInheritedDSAType =
    llvm::SmallDenseMap<const ValueDecl *, const Expr *, 4>;
/// Called on well-formed '\#pragma omp simd' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                         SourceLocation StartLoc, SourceLocation EndLoc,
                         VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp for' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPForDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                        SourceLocation StartLoc, SourceLocation EndLoc,
                        VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp for simd' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPForSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                            SourceLocation StartLoc, SourceLocation EndLoc,
                            VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp sections' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPSectionsDirective(ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp section' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPSectionDirective(Stmt *AStmt, SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp single' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPSingleDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp master' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPMasterDirective(Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp critical' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPCriticalDirective(const DeclarationNameInfo &DirName,
                                        ArrayRef<OMPClause *> Clauses,
                                        Stmt *AStmt, SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp parallel for' after parsing
/// of the  associated statement.
StmtResult ActOnOpenMPParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel for simd' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel sections' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPParallelSectionsDirective(ArrayRef<OMPClause *> Clauses,
                                                Stmt *AStmt,
                                                SourceLocation StartLoc,
                                                SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp task' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTaskDirective(ArrayRef<OMPClause *> Clauses,
                                    Stmt *AStmt, SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskyield'.
StmtResult ActOnOpenMPTaskyieldDirective(SourceLocation StartLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp barrier'.
StmtResult ActOnOpenMPBarrierDirective(SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskwait'.
StmtResult ActOnOpenMPTaskwaitDirective(SourceLocation StartLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp taskgroup'.
StmtResult ActOnOpenMPTaskgroupDirective(ArrayRef<OMPClause *> Clauses,
                                         Stmt *AStmt, SourceLocation StartLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp flush'.
StmtResult ActOnOpenMPFlushDirective(ArrayRef<OMPClause *> Clauses,
                                     SourceLocation StartLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp ordered' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
                                       Stmt *AStmt, SourceLocation StartLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp atomic' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTargetDirective(ArrayRef<OMPClause *> Clauses,
                                      Stmt *AStmt, SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target data' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTargetDataDirective(ArrayRef<OMPClause *> Clauses,
                                          Stmt *AStmt, SourceLocation StartLoc,
                                          SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target enter data' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetEnterDataDirective(ArrayRef<OMPClause *> Clauses,
                                               SourceLocation StartLoc,
                                               SourceLocation EndLoc,
                                               Stmt *AStmt);
/// Called on well-formed '\#pragma omp target exit data' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetExitDataDirective(ArrayRef<OMPClause *> Clauses,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc,
                                              Stmt *AStmt);
/// Called on well-formed '\#pragma omp target parallel' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetParallelDirective(ArrayRef<OMPClause *> Clauses,
                                              Stmt *AStmt,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target parallel for' after
/// parsing of the  associated statement.
StmtResult ActOnOpenMPTargetParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTeamsDirective(ArrayRef<OMPClause *> Clauses,
                                     Stmt *AStmt, SourceLocation StartLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp cancellation point'.
StmtResult
ActOnOpenMPCancellationPointDirective(SourceLocation StartLoc,
                                      SourceLocation EndLoc,
                                      OpenMPDirectiveKind CancelRegion);
/// Called on well-formed '\#pragma omp cancel'.
StmtResult ActOnOpenMPCancelDirective(ArrayRef<OMPClause *> Clauses,
                                      SourceLocation StartLoc,
                                      SourceLocation EndLoc,
                                      OpenMPDirectiveKind CancelRegion);
/// Called on well-formed '\#pragma omp taskloop' after parsing of the
/// associated statement.
StmtResult
ActOnOpenMPTaskLoopDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                             SourceLocation StartLoc, SourceLocation EndLoc,
                             VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp taskloop simd' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTaskLoopSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp master taskloop' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPMasterTaskLoopDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp parallel master taskloop' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPParallelMasterTaskLoopDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute' after parsing
/// of the associated statement.
StmtResult
ActOnOpenMPDistributeDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                               SourceLocation StartLoc, SourceLocation EndLoc,
                               VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target update'.
StmtResult ActOnOpenMPTargetUpdateDirective(ArrayRef<OMPClause *> Clauses,
                                            SourceLocation StartLoc,
                                            SourceLocation EndLoc,
                                            Stmt *AStmt);
/// Called on well-formed '\#pragma omp distribute parallel for' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute parallel for simd'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp distribute simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target parallel for simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target simd' after parsing of
/// the associated statement.
StmtResult
ActOnOpenMPTargetSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                               SourceLocation StartLoc, SourceLocation EndLoc,
                               VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute' after parsing of
/// the associated statement.
StmtResult ActOnOpenMPTeamsDistributeDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute simd' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute parallel for simd'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp teams distribute parallel for'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTeamsDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams' after parsing of the
/// associated statement.
StmtResult ActOnOpenMPTargetTeamsDirective(ArrayRef<OMPClause *> Clauses,
                                           Stmt *AStmt,
                                           SourceLocation StartLoc,
                                           SourceLocation EndLoc);
/// Called on well-formed '\#pragma omp target teams distribute' after parsing
/// of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute parallel for'
/// after parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeParallelForDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute parallel for
/// simd' after parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeParallelForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);
/// Called on well-formed '\#pragma omp target teams distribute simd' after
/// parsing of the associated statement.
StmtResult ActOnOpenMPTargetTeamsDistributeSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA);

/// Checks correctness of linear modifiers.
bool CheckOpenMPLinearModifier(OpenMPLinearClauseKind LinKind,
                               SourceLocation LinLoc);
/// Checks that the specified declaration matches requirements for the linear
/// decls.
bool CheckOpenMPLinearDecl(const ValueDecl *D, SourceLocation ELoc,
                           OpenMPLinearClauseKind LinKind, QualType Type);

/// Called on well-formed '\#pragma omp declare simd' after parsing of
/// the associated method/function.
DeclGroupPtrTy ActOnOpenMPDeclareSimdDirective(
    DeclGroupPtrTy DG, OMPDeclareSimdDeclAttr::BranchStateTy BS,
    Expr *Simdlen, ArrayRef<Expr *> Uniforms, ArrayRef<Expr *> Aligneds,
    ArrayRef<Expr *> Alignments, ArrayRef<Expr *> Linears,
    ArrayRef<unsigned> LinModifiers, ArrayRef<Expr *> Steps, SourceRange SR);

/// Checks '\#pragma omp declare variant' variant function and original
/// functions after parsing of the associated method/function.
/// \param DG Function declaration to which declare variant directive is
/// applied to.
/// \param VariantRef Expression that references the variant function, which
/// must be used instead of the original one, specified in \p DG.
/// \returns None, if the function/variant function are not compatible with
/// the pragma, pair of original function/variant ref expression otherwise.
Optional<std::pair<FunctionDecl *, Expr *>> checkOpenMPDeclareVariantFunction(
    DeclGroupPtrTy DG, Expr *VariantRef, SourceRange SR);

/// Called on well-formed '\#pragma omp declare variant' after parsing of
/// the associated method/function.
/// \param FD Function declaration to which declare variant directive is
/// applied to.
/// \param VariantRef Expression that references the variant function, which
/// must be used instead of the original one, specified in \p DG.
/// \param Data Set of context-specific data for the specified context
/// selector.
void ActOnOpenMPDeclareVariantDirective(
    FunctionDecl *FD, Expr *VariantRef, SourceRange SR,
    const Sema::OpenMPDeclareVariantCtsSelectorData &Data);

OMPClause *ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind,
                                       Expr *Expr,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'allocator' clause.
OMPClause *ActOnOpenMPAllocatorClause(Expr *Allocator,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'if' clause.
OMPClause *ActOnOpenMPIfClause(OpenMPDirectiveKind NameModifier,
                               Expr *Condition, SourceLocation StartLoc,
                               SourceLocation LParenLoc,
                               SourceLocation NameModifierLoc,
                               SourceLocation ColonLoc,
                               SourceLocation EndLoc);
/// Called on well-formed 'final' clause.
OMPClause *ActOnOpenMPFinalClause(Expr *Condition, SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'num_threads' clause.
OMPClause *ActOnOpenMPNumThreadsClause(Expr *NumThreads,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc);
/// Called on well-formed 'safelen' clause.
OMPClause *ActOnOpenMPSafelenClause(Expr *Length,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'simdlen' clause.
OMPClause *ActOnOpenMPSimdlenClause(Expr *Length, SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'collapse' clause.
OMPClause *ActOnOpenMPCollapseClause(Expr *NumForLoops,
                                     SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'ordered' clause.
OMPClause *
ActOnOpenMPOrderedClause(SourceLocation StartLoc, SourceLocation EndLoc,
                         SourceLocation LParenLoc = SourceLocation(),
                         Expr *NumForLoops = nullptr);
/// Called on well-formed 'grainsize' clause.
OMPClause *ActOnOpenMPGrainsizeClause(Expr *Size, SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'num_tasks' clause.
OMPClause *ActOnOpenMPNumTasksClause(Expr *NumTasks, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'hint' clause.
OMPClause *ActOnOpenMPHintClause(Expr *Hint, SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation EndLoc);

OMPClause *ActOnOpenMPSimpleClause(OpenMPClauseKind Kind,
                                   unsigned Argument,
                                   SourceLocation ArgumentLoc,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'default' clause.
OMPClause *ActOnOpenMPDefaultClause(OpenMPDefaultClauseKind Kind,
                                    SourceLocation KindLoc,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'proc_bind' clause.
OMPClause *ActOnOpenMPProcBindClause(OpenMPProcBindClauseKind Kind,
                                     SourceLocation KindLoc,
                                     SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);

OMPClause *ActOnOpenMPSingleExprWithArgClause(
    OpenMPClauseKind Kind, ArrayRef<unsigned> Arguments, Expr *Expr,
    SourceLocation StartLoc, SourceLocation LParenLoc,
    ArrayRef<SourceLocation> ArgumentsLoc, SourceLocation DelimLoc,
    SourceLocation EndLoc);
/// Called on well-formed 'schedule' clause.
OMPClause *ActOnOpenMPScheduleClause(
    OpenMPScheduleClauseModifier M1, OpenMPScheduleClauseModifier M2,
    OpenMPScheduleClauseKind Kind, Expr *ChunkSize, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation M1Loc, SourceLocation M2Loc,
    SourceLocation KindLoc, SourceLocation CommaLoc, SourceLocation EndLoc);

OMPClause *ActOnOpenMPClause(OpenMPClauseKind Kind, SourceLocation StartLoc,
                             SourceLocation EndLoc);
/// Called on well-formed 'nowait' clause.
OMPClause *ActOnOpenMPNowaitClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'untied' clause.
OMPClause *ActOnOpenMPUntiedClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'mergeable' clause.
OMPClause *ActOnOpenMPMergeableClause(SourceLocation StartLoc,
                                      SourceLocation EndLoc);
/// Called on well-formed 'read' clause.
OMPClause *ActOnOpenMPReadClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'write' clause.
OMPClause *ActOnOpenMPWriteClause(SourceLocation StartLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'update' clause.
OMPClause *ActOnOpenMPUpdateClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'capture' clause.
OMPClause *ActOnOpenMPCaptureClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'seq_cst' clause.
OMPClause *ActOnOpenMPSeqCstClause(SourceLocation StartLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'threads' clause.
OMPClause *ActOnOpenMPThreadsClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'simd' clause.
OMPClause *ActOnOpenMPSIMDClause(SourceLocation StartLoc,
                                 SourceLocation EndLoc);
/// Called on well-formed 'nogroup' clause.
OMPClause *ActOnOpenMPNogroupClause(SourceLocation StartLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'unified_address' clause.
OMPClause *ActOnOpenMPUnifiedAddressClause(SourceLocation StartLoc,
                                           SourceLocation EndLoc);

/// Called on well-formed 'unified_address' clause.
OMPClause *ActOnOpenMPUnifiedSharedMemoryClause(SourceLocation StartLoc,
                                                SourceLocation EndLoc);

/// Called on well-formed 'reverse_offload' clause.
OMPClause *ActOnOpenMPReverseOffloadClause(SourceLocation StartLoc,
                                           SourceLocation EndLoc);

/// Called on well-formed 'dynamic_allocators' clause.
OMPClause *ActOnOpenMPDynamicAllocatorsClause(SourceLocation StartLoc,
                                              SourceLocation EndLoc);

/// Called on well-formed 'atomic_default_mem_order' clause.
OMPClause *ActOnOpenMPAtomicDefaultMemOrderClause(
    OpenMPAtomicDefaultMemOrderClauseKind Kind, SourceLocation KindLoc,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation EndLoc);

OMPClause *ActOnOpenMPVarListClause(
    OpenMPClauseKind Kind, ArrayRef<Expr *> Vars, Expr *TailExpr,
    const OMPVarListLocTy &Locs, SourceLocation ColonLoc,
    CXXScopeSpec &ReductionOrMapperIdScopeSpec,
    DeclarationNameInfo &ReductionOrMapperId, OpenMPDependClauseKind DepKind,
    OpenMPLinearClauseKind LinKind,
    ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
    ArrayRef<SourceLocation> MapTypeModifiersLoc, OpenMPMapClauseKind MapType,
    bool IsMapTypeImplicit, SourceLocation DepLinMapLoc);
/// Called on well-formed 'allocate' clause.
OMPClause *
ActOnOpenMPAllocateClause(Expr *Allocator, ArrayRef<Expr *> VarList,
                          SourceLocation StartLoc, SourceLocation ColonLoc,
                          SourceLocation LParenLoc, SourceLocation EndLoc);
/// Called on well-formed 'private' clause.
OMPClause *ActOnOpenMPPrivateClause(ArrayRef<Expr *> VarList,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'firstprivate' clause.
OMPClause *ActOnOpenMPFirstprivateClause(ArrayRef<Expr *> VarList,
                                         SourceLocation StartLoc,
                                         SourceLocation LParenLoc,
                                         SourceLocation EndLoc);
/// Called on well-formed 'lastprivate' clause.
OMPClause *ActOnOpenMPLastprivateClause(ArrayRef<Expr *> VarList,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed 'shared' clause.
OMPClause *ActOnOpenMPSharedClause(ArrayRef<Expr *> VarList,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'reduction' clause.
OMPClause *ActOnOpenMPReductionClause(
    ArrayRef<Expr *> VarList, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation ColonLoc, SourceLocation EndLoc,
    CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'task_reduction' clause.
OMPClause *ActOnOpenMPTaskReductionClause(
    ArrayRef<Expr *> VarList, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation ColonLoc, SourceLocation EndLoc,
    CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'in_reduction' clause.
OMPClause *ActOnOpenMPInReductionClause(
    ArrayRef<Expr *> VarList, SourceLocation StartLoc,
    SourceLocation LParenLoc, SourceLocation ColonLoc, SourceLocation EndLoc,
    CXXScopeSpec &ReductionIdScopeSpec,
    const DeclarationNameInfo &ReductionId,
    ArrayRef<Expr *> UnresolvedReductions = llvm::None);
/// Called on well-formed 'linear' clause.
OMPClause *
ActOnOpenMPLinearClause(ArrayRef<Expr *> VarList, Expr *Step,
                        SourceLocation StartLoc, SourceLocation LParenLoc,
                        OpenMPLinearClauseKind LinKind, SourceLocation LinLoc,
                        SourceLocation ColonLoc, SourceLocation EndLoc);
/// Called on well-formed 'aligned' clause.
OMPClause *ActOnOpenMPAlignedClause(ArrayRef<Expr *> VarList,
                                    Expr *Alignment,
                                    SourceLocation StartLoc,
                                    SourceLocation LParenLoc,
                                    SourceLocation ColonLoc,
                                    SourceLocation EndLoc);
/// Called on well-formed 'copyin' clause.
OMPClause *ActOnOpenMPCopyinClause(ArrayRef<Expr *> VarList,
                                   SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'copyprivate' clause.
OMPClause *ActOnOpenMPCopyprivateClause(ArrayRef<Expr *> VarList,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed 'flush' pseudo clause.
OMPClause *ActOnOpenMPFlushClause(ArrayRef<Expr *> VarList,
                                  SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);
/// Called on well-formed 'depend' clause.
OMPClause *
ActOnOpenMPDependClause(OpenMPDependClauseKind DepKind, SourceLocation DepLoc,
                        SourceLocation ColonLoc, ArrayRef<Expr *> VarList,
                        SourceLocation StartLoc, SourceLocation LParenLoc,
                        SourceLocation EndLoc);
/// Called on well-formed 'device' clause.
OMPClause *ActOnOpenMPDeviceClause(Expr *Device, SourceLocation StartLoc,
                                   SourceLocation LParenLoc,
                                   SourceLocation EndLoc);
/// Called on well-formed 'map' clause.
OMPClause *
ActOnOpenMPMapClause(ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
                     ArrayRef<SourceLocation> MapTypeModifiersLoc,
                     CXXScopeSpec &MapperIdScopeSpec,
                     DeclarationNameInfo &MapperId,
                     OpenMPMapClauseKind MapType, bool IsMapTypeImplicit,
                     SourceLocation MapLoc, SourceLocation ColonLoc,
                     ArrayRef<Expr *> VarList, const OMPVarListLocTy &Locs,
                     ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'num_teams' clause.
OMPClause *ActOnOpenMPNumTeamsClause(Expr *NumTeams, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'thread_limit' clause.
OMPClause *ActOnOpenMPThreadLimitClause(Expr *ThreadLimit,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
/// Called on well-formed 'priority' clause.
OMPClause *ActOnOpenMPPriorityClause(Expr *Priority, SourceLocation StartLoc,
                                     SourceLocation LParenLoc,
                                     SourceLocation EndLoc);
/// Called on well-formed 'dist_schedule' clause.
OMPClause *ActOnOpenMPDistScheduleClause(
    OpenMPDistScheduleClauseKind Kind, Expr *ChunkSize,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation KindLoc,
    SourceLocation CommaLoc, SourceLocation EndLoc);
/// Called on well-formed 'defaultmap' clause.
OMPClause *ActOnOpenMPDefaultmapClause(
    OpenMPDefaultmapClauseModifier M, OpenMPDefaultmapClauseKind Kind,
    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation MLoc,
    SourceLocation KindLoc, SourceLocation EndLoc);
/// Called on well-formed 'to' clause.
OMPClause *
ActOnOpenMPToClause(ArrayRef<Expr *> VarList, CXXScopeSpec &MapperIdScopeSpec,
                    DeclarationNameInfo &MapperId,
                    const OMPVarListLocTy &Locs,
                    ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'from' clause.
OMPClause *ActOnOpenMPFromClause(
    ArrayRef<Expr *> VarList, CXXScopeSpec &MapperIdScopeSpec,
    DeclarationNameInfo &MapperId, const OMPVarListLocTy &Locs,
    ArrayRef<Expr *> UnresolvedMappers = llvm::None);
/// Called on well-formed 'use_device_ptr' clause.
OMPClause *ActOnOpenMPUseDevicePtrClause(ArrayRef<Expr *> VarList,
                                         const OMPVarListLocTy &Locs);
/// Called on well-formed 'is_device_ptr' clause.
OMPClause *ActOnOpenMPIsDevicePtrClause(ArrayRef<Expr *> VarList,
                                        const OMPVarListLocTy &Locs);

/// The kind of conversion being performed.
enum CheckedConversionKind {
  /// An implicit conversion.
  CCK_ImplicitConversion,
  /// A C-style cast.
  CCK_CStyleCast,
  /// A functional-style cast.
  CCK_FunctionalCast,
  /// A cast other than a C-style cast.
  CCK_OtherCast,
  /// A conversion for an operand of a builtin overloaded operator.
  CCK_ForBuiltinOverloadedOp
};

static bool isCast(CheckedConversionKind CCK) {
  return CCK == CCK_CStyleCast || CCK == CCK_FunctionalCast ||
         CCK == CCK_OtherCast;
}

/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit
/// cast.  If there is already an implicit cast, merge into the existing one.
/// If isLvalue, the result of the cast is an lvalue.
ExprResult ImpCastExprToType(Expr *E, QualType Type, CastKind CK,
                             ExprValueKind VK = VK_RValue,
                             const CXXCastPath *BasePath = nullptr,
                             CheckedConversionKind CCK
                                = CCK_ImplicitConversion);

/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
/// to the conversion from scalar type ScalarTy to the Boolean type.
static CastKind ScalarTypeToBooleanCastKind(QualType ScalarTy);

/// IgnoredValueConversions - Given that an expression's result is
/// syntactically ignored, perform any conversions that are
/// required.
ExprResult IgnoredValueConversions(Expr *E);

// UsualUnaryConversions - promotes integers (C99 6.3.1.1p2) and converts
// functions and arrays to their respective pointers (C99 6.3.2.1).
ExprResult UsualUnaryConversions(Expr *E);

/// CallExprUnaryConversions - a special case of an unary conversion
/// performed on a function designator of a call expression.
ExprResult CallExprUnaryConversions(Expr *E);

// DefaultFunctionArrayConversion - converts functions and arrays
// to their respective pointers (C99 6.3.2.1).
ExprResult DefaultFunctionArrayConversion(Expr *E, bool Diagnose = true);

// DefaultFunctionArrayLvalueConversion - converts functions and
// arrays to their respective pointers and performs the
// lvalue-to-rvalue conversion.
ExprResult DefaultFunctionArrayLvalueConversion(Expr *E,
                                                bool Diagnose = true);

// DefaultLvalueConversion - performs lvalue-to-rvalue conversion on
// the operand.  This is DefaultFunctionArrayLvalueConversion,
// except that it assumes the operand isn't of function or array
// type.
ExprResult DefaultLvalueConversion(Expr *E);

// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
// do not have a prototype. Integer promotions are performed on each
// argument, and arguments that have type float are promoted to double.
ExprResult DefaultArgumentPromotion(Expr *E);

/// If \p E is a prvalue denoting an unmaterialized temporary, materialize
/// it as an xvalue. In C++98, the result will still be a prvalue, because
/// we don't have xvalues there.
ExprResult TemporaryMaterializationConversion(Expr *E);

// Used for emitting the right warning by DefaultVariadicArgumentPromotion
enum VariadicCallType {
  VariadicFunction,
  VariadicBlock,
  VariadicMethod,
  VariadicConstructor,
  VariadicDoesNotApply
};

VariadicCallType getVariadicCallType(FunctionDecl *FDecl,
                                     const FunctionProtoType *Proto,
                                     Expr *Fn);

// Used for determining in which context a type is allowed to be passed to a
// vararg function.
enum VarArgKind {
  VAK_Valid,
  VAK_ValidInCXX11,
  VAK_Undefined,
  VAK_MSVCUndefined,
  VAK_Invalid
};

// Determines which VarArgKind fits an expression.
VarArgKind isValidVarArgType(const QualType &Ty);

/// Check to see if the given expression is a valid argument to a variadic
/// function, issuing a diagnostic if not.
void checkVariadicArgument(const Expr *E, VariadicCallType CT);

/// Check to see if a given expression could have '.c_str()' called on it.
bool hasCStrMethod(const Expr *E);

/// GatherArgumentsForCall - Collector argument expressions for various
/// form of call prototypes.
bool GatherArgumentsForCall(SourceLocation CallLoc, FunctionDecl *FDecl,
                            const FunctionProtoType *Proto,
                            unsigned FirstParam, ArrayRef<Expr *> Args,
                            SmallVectorImpl<Expr *> &AllArgs,
                            VariadicCallType CallType = VariadicDoesNotApply,
                            bool AllowExplicit = false,
                            bool IsListInitialization = false);

// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
// will create a runtime trap if the resulting type is not a POD type.
ExprResult DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
                                            FunctionDecl *FDecl);

// UsualArithmeticConversions - performs the UsualUnaryConversions on it's
// operands and then handles various conversions that are common to binary
// operators (C99 6.3.1.8). If both operands aren't arithmetic, this
// routine returns the first non-arithmetic type found. The client is
// responsible for emitting appropriate error diagnostics.
QualType UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
                                    bool IsCompAssign = false);

/// AssignConvertType - All of the 'assignment' semantic checks return this
/// enum to indicate whether the assignment was allowed.  These checks are
/// done for simple assignments, as well as initialization, return from
/// function, argument passing, etc.  The query is phrased in terms of a
/// source and destination type.
enum AssignConvertType {
  /// Compatible - the types are compatible according to the standard.
  Compatible,

  /// PointerToInt - The assignment converts a pointer to an int, which we
  /// accept as an extension.
  PointerToInt,

  /// IntToPointer - The assignment converts an int to a pointer, which we
  /// accept as an extension.
  IntToPointer,

  /// FunctionVoidPointer - The assignment is between a function pointer and
  /// void*, which the standard doesn't allow, but we accept as an extension.
  FunctionVoidPointer,

  /// IncompatiblePointer - The assignment is between two pointers types that
  /// are not compatible, but we accept them as an extension.
  IncompatiblePointer,

  /// IncompatiblePointerSign - The assignment is between two pointers types
  /// which point to integers which have a different sign, but are otherwise
  /// identical. This is a subset of the above, but broken out because it's by
  /// far the most common case of incompatible pointers.
  IncompatiblePointerSign,

  /// CompatiblePointerDiscardsQualifiers - The assignment discards
  /// c/v/r qualifiers, which we accept as an extension.
  CompatiblePointerDiscardsQualifiers,

  /// IncompatiblePointerDiscardsQualifiers - The assignment
  /// discards qualifiers that we don't permit to be discarded,
  /// like address spaces.
  IncompatiblePointerDiscardsQualifiers,

  /// IncompatibleNestedPointerAddressSpaceMismatch - The assignment
  /// changes address spaces in nested pointer types which is not allowed.
  /// For instance, converting __private int ** to __generic int ** is
  /// illegal even though __private could be converted to __generic.
  IncompatibleNestedPointerAddressSpaceMismatch,

  /// IncompatibleNestedPointerQualifiers - The assignment is between two
  /// nested pointer types, and the qualifiers other than the first two
  /// levels differ e.g. char ** -> const char **, but we accept them as an
  /// extension.
  IncompatibleNestedPointerQualifiers,

  /// IncompatibleVectors - The assignment is between two vector types that
  /// have the same size, which we accept as an extension.
  IncompatibleVectors,

  /// IntToBlockPointer - The assignment converts an int to a block
  /// pointer. We disallow this.
  IntToBlockPointer,

  /// IncompatibleBlockPointer - The assignment is between two block
  /// pointers types that are not compatible.
  IncompatibleBlockPointer,

  /// IncompatibleObjCQualifiedId - The assignment is between a qualified
  /// id type and something else (that is incompatible with it). For example,
  /// "id <XXX>" = "Foo *", where "Foo *" doesn't implement the XXX protocol.
  IncompatibleObjCQualifiedId,

  /// IncompatibleObjCWeakRef - Assigning a weak-unavailable object to an
  /// object with __weak qualifier.
  IncompatibleObjCWeakRef,

  /// Incompatible - We reject this conversion outright, it is invalid to
  /// represent it in the AST.
  Incompatible
};

/// DiagnoseAssignmentResult - Emit a diagnostic, if required, for the
/// assignment conversion type specified by ConvTy.  This returns true if the
/// conversion was invalid or false if the conversion was accepted.
bool DiagnoseAssignmentResult(AssignConvertType ConvTy,
                              SourceLocation Loc,
                              QualType DstType, QualType SrcType,
                              Expr *SrcExpr, AssignmentAction Action,
                              bool *Complained = nullptr);

/// IsValueInFlagEnum - Determine if a value is allowed as part of a flag
/// enum. If AllowMask is true, then we also allow the complement of a valid
/// value, to be used as a mask.
bool IsValueInFlagEnum(const EnumDecl *ED, const llvm::APInt &Val,
                       bool AllowMask) const;

/// DiagnoseAssignmentEnum - Warn if assignment to enum is a constant
/// integer not in the range of enum values.
void DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
                            Expr *SrcExpr);

/// CheckAssignmentConstraints - Perform type checking for assignment,
/// argument passing, variable initialization, and function return values.
/// C99 6.5.16.
AssignConvertType CheckAssignmentConstraints(SourceLocation Loc,
                                             QualType LHSType,
                                             QualType RHSType);

/// Check assignment constraints and optionally prepare for a conversion of
/// the RHS to the LHS type. The conversion is prepared for if ConvertRHS
/// is true.
AssignConvertType CheckAssignmentConstraints(QualType LHSType,
                                             ExprResult &RHS,
                                             CastKind &Kind,
                                             bool ConvertRHS = true);

/// Check assignment constraints for an assignment of RHS to LHSType.
///
/// \param LHSType The destination type for the assignment.
/// \param RHS The source expression for the assignment.
/// \param Diagnose If \c true, diagnostics may be produced when checking
///        for assignability. If a diagnostic is produced, \p RHS will be
///        set to ExprError(). Note that this function may still return
///        without producing a diagnostic, even for an invalid assignment.
/// \param DiagnoseCFAudited If \c true, the target is a function parameter
///        in an audited Core Foundation API and does not need to be checked
///        for ARC retain issues.
/// \param ConvertRHS If \c true, \p RHS will be updated to model the
///        conversions necessary to perform the assignment. If \c false,
///        \p Diagnose must also be \c false.
AssignConvertType CheckSingleAssignmentConstraints(
    QualType LHSType, ExprResult &RHS, bool Diagnose = true,
    bool DiagnoseCFAudited = false, bool ConvertRHS = true);

// If the lhs type is a transparent union, check whether we
// can initialize the transparent union with the given expression.
AssignConvertType CheckTransparentUnionArgumentConstraints(QualType ArgType,
                                                           ExprResult &RHS);

bool IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType);

bool CheckExceptionSpecCompatibility(Expr *From, QualType ToType);

ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     AssignmentAction Action,
                                     bool AllowExplicit = false);
ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     AssignmentAction Action,
                                     bool AllowExplicit,
                                     ImplicitConversionSequence& ICS);
ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     const ImplicitConversionSequence& ICS,
                                     AssignmentAction Action,
                                     CheckedConversionKind CCK
                                        = CCK_ImplicitConversion);
ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                     const StandardConversionSequence& SCS,
                                     AssignmentAction Action,
                                     CheckedConversionKind CCK);

ExprResult PerformQualificationConversion(
    Expr *E, QualType Ty, ExprValueKind VK = VK_RValue,
    CheckedConversionKind CCK = CCK_ImplicitConversion);

/// the following "Check" methods will return a valid/converted QualType
/// or a null QualType (indicating an error diagnostic was issued).

/// type checking binary operators (subroutines of CreateBuiltinBinOp).
QualType InvalidOperands(SourceLocation Loc, ExprResult &LHS,
                         ExprResult &RHS);
QualType InvalidLogicalVectorOperands(SourceLocation Loc, ExprResult &LHS,
                               ExprResult &RHS);
QualType CheckPointerToMemberOperands( // C++ 5.5
  ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK,
  SourceLocation OpLoc, bool isIndirect);
QualType CheckMultiplyDivideOperands( // C99 6.5.5
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc, bool IsCompAssign,
  bool IsDivide);
QualType CheckRemainderOperands( // C99 6.5.5
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  bool IsCompAssign = false);
QualType CheckAdditionOperands( // C99 6.5.6
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc, QualType* CompLHSTy = nullptr);
QualType CheckSubtractionOperands( // C99 6.5.6
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  QualType* CompLHSTy = nullptr);
QualType CheckShiftOperands( // C99 6.5.7
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc, bool IsCompAssign = false);
void CheckPtrComparisonWithNullChar(ExprResult &E, ExprResult &NullE);
QualType CheckCompareOperands( // C99 6.5.8/9
    ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
    BinaryOperatorKind Opc);
QualType CheckBitwiseOperands( // C99 6.5.[10...12]
    ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
    BinaryOperatorKind Opc);
QualType CheckLogicalOperands( // C99 6.5.[13,14]
  ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
  BinaryOperatorKind Opc);
// CheckAssignmentOperands is used for both simple and compound assignment.
// For simple assignment, pass both expressions and a null converted type.
// For compound assignment, pass both expressions and the converted type.
QualType CheckAssignmentOperands( // C99 6.5.16.[1,2]
  Expr *LHSExpr, ExprResult &RHS, SourceLocation Loc, QualType CompoundType);

ExprResult checkPseudoObjectIncDec(Scope *S, SourceLocation OpLoc,
                                   UnaryOperatorKind Opcode, Expr *Op);
ExprResult checkPseudoObjectAssignment(Scope *S, SourceLocation OpLoc,
                                       BinaryOperatorKind Opcode,
                                       Expr *LHS, Expr *RHS);
ExprResult checkPseudoObjectRValue(Expr *E);
Expr *recreateSyntacticForm(PseudoObjectExpr *E);

QualType CheckConditionalOperands( // C99 6.5.15
  ExprResult &Cond, ExprResult &LHS, ExprResult &RHS,
  ExprValueKind &VK, ExprObjectKind &OK, SourceLocation QuestionLoc);
QualType CXXCheckConditionalOperands( // C++ 5.16
  ExprResult &cond, ExprResult &lhs, ExprResult &rhs,
  ExprValueKind &VK, ExprObjectKind &OK, SourceLocation questionLoc);
QualType FindCompositePointerType(SourceLocation Loc, Expr *&E1, Expr *&E2,
                                  bool ConvertArgs = true);
QualType FindCompositePointerType(SourceLocation Loc,
                                  ExprResult &E1, ExprResult &E2,
                                  bool ConvertArgs = true) {
  Expr *E1Tmp = E1.get(), *E2Tmp = E2.get();
  QualType Composite =
      FindCompositePointerType(Loc, E1Tmp, E2Tmp, ConvertArgs);
  E1 = E1Tmp;
  E2 = E2Tmp;
  return Composite;
}

QualType FindCompositeObjCPointerType(ExprResult &LHS, ExprResult &RHS,
                                      SourceLocation QuestionLoc);

bool DiagnoseConditionalForNull(Expr *LHSExpr, Expr *RHSExpr,
                                SourceLocation QuestionLoc);

void DiagnoseAlwaysNonNullPointer(Expr *E,
                                  Expr::NullPointerConstantKind NullType,
                                  bool IsEqual, SourceRange Range);

/// type checking for vector binary operators.
QualType CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
                             SourceLocation Loc, bool IsCompAssign,
                             bool AllowBothBool, bool AllowBoolConversion);
QualType GetSignedVectorType(QualType V);
QualType CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc,
                                    BinaryOperatorKind Opc);
QualType CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation Loc);

bool areLaxCompatibleVectorTypes(QualType srcType, QualType destType);
bool isLaxVectorConversion(QualType srcType, QualType destType);

/// type checking declaration initializers (C99 6.7.8)
bool CheckForConstantInitializer(Expr *e, QualType t);

// type checking C++ declaration initializers (C++ [dcl.init]).

/// ReferenceCompareResult - Expresses the result of comparing two
/// types (cv1 T1 and cv2 T2) to determine their compatibility for the
/// purposes of initialization by reference (C++ [dcl.init.ref]p4).
enum ReferenceCompareResult {
  /// Ref_Incompatible - The two types are incompatible, so direct
  /// reference binding is not possible.
  Ref_Incompatible = 0,
  /// Ref_Related - The two types are reference-related, which means
  /// that their unqualified forms (T1 and T2) are either the same
  /// or T1 is a base class of T2.
  Ref_Related,
  /// Ref_Compatible - The two types are reference-compatible.
  Ref_Compatible
};

ReferenceCompareResult CompareReferenceRelationship(SourceLocation Loc,
                                                    QualType T1, QualType T2,
                                                    bool &DerivedToBase,
                                                    bool &ObjCConversion,
                                              bool &ObjCLifetimeConversion);

ExprResult checkUnknownAnyCast(SourceRange TypeRange, QualType CastType,
                               Expr *CastExpr, CastKind &CastKind,
                               ExprValueKind &VK, CXXCastPath &Path);

/// Force an expression with unknown-type to an expression of the
/// given type.
ExprResult forceUnknownAnyToType(Expr *E, QualType ToType);

/// Type-check an expression that's being passed to an
/// __unknown_anytype parameter.
ExprResult checkUnknownAnyArg(SourceLocation callLoc,
                              Expr *result, QualType &paramType);

// CheckVectorCast - check type constraints for vectors.
// Since vectors are an extension, there are no C standard reference for this.
// We allow casting between vectors and integer datatypes of the same size.
// returns true if the cast is invalid
bool CheckVectorCast(SourceRange R, QualType VectorTy, QualType Ty,
                     CastKind &Kind);

/// Prepare `SplattedExpr` for a vector splat operation, adding
/// implicit casts if necessary.
ExprResult prepareVectorSplat(QualType VectorTy, Expr *SplattedExpr);

// CheckExtVectorCast - check type constraints for extended vectors.
// Since vectors are an extension, there are no C standard reference for this.
// We allow casting between vectors and integer datatypes of the same size,
// or vectors and the element type of that vector.
// returns the cast expr
ExprResult CheckExtVectorCast(SourceRange R, QualType DestTy, Expr *CastExpr,
                              CastKind &Kind);

ExprResult BuildCXXFunctionalCastExpr(TypeSourceInfo *TInfo, QualType Type,
                                      SourceLocation LParenLoc,
                                      Expr *CastExpr,
                                      SourceLocation RParenLoc);

enum ARCConversionResult { ACR_okay, ACR_unbridged, ACR_error };

/// Checks for invalid conversions and casts between
/// retainable pointers and other pointer kinds for ARC and Weak.
ARCConversionResult CheckObjCConversion(SourceRange castRange,
                                        QualType castType, Expr *&op,
                                        CheckedConversionKind CCK,
                                        bool Diagnose = true,
                                        bool DiagnoseCFAudited = false,
                                        BinaryOperatorKind Opc = BO_PtrMemD
                                        );

Expr *stripARCUnbridgedCast(Expr *e);
void diagnoseARCUnbridgedCast(Expr *e);

bool CheckObjCARCUnavailableWeakConversion(QualType castType,
                                           QualType ExprType);

/// checkRetainCycles - Check whether an Objective-C message send
/// might create an obvious retain cycle.
void checkRetainCycles(ObjCMessageExpr *msg);
void checkRetainCycles(Expr *receiver, Expr *argument);
void checkRetainCycles(VarDecl *Var, Expr *Init);

/// checkUnsafeAssigns - Check whether +1 expr is being assigned
/// to weak/__unsafe_unretained type.
bool checkUnsafeAssigns(SourceLocation Loc, QualType LHS, Expr *RHS);

/// checkUnsafeExprAssigns - Check whether +1 expr is being assigned
/// to weak/__unsafe_unretained expression.
void checkUnsafeExprAssigns(SourceLocation Loc, Expr *LHS, Expr *RHS);

/// CheckMessageArgumentTypes - Check types in an Obj-C message send.
/// \param Method - May be null.
/// \param [out] ReturnType - The return type of the send.
/// \return true iff there were any incompatible types.
bool CheckMessageArgumentTypes(const Expr *Receiver, QualType ReceiverType,
                               MultiExprArg Args, Selector Sel,
                               ArrayRef<SourceLocation> SelectorLocs,
                               ObjCMethodDecl *Method, bool isClassMessage,
                               bool isSuperMessage, SourceLocation lbrac,
                               SourceLocation rbrac, SourceRange RecRange,
                               QualType &ReturnType, ExprValueKind &VK);

/// Determine the result of a message send expression based on
/// the type of the receiver, the method expected to receive the message,
/// and the form of the message send.
QualType getMessageSendResultType(const Expr *Receiver, QualType ReceiverType,
                                  ObjCMethodDecl *Method, bool isClassMessage,
                                  bool isSuperMessage);

/// If the given expression involves a message send to a method
/// with a related result type, emit a note describing what happened.
void EmitRelatedResultTypeNote(const Expr *E);

/// Given that we had incompatible pointer types in a return
/// statement, check whether we're in a method with a related result
/// type, and if so, emit a note describing what happened.
void EmitRelatedResultTypeNoteForReturn(QualType destType);

class ConditionResult {
  Decl *ConditionVar;
  FullExprArg Condition;
  bool Invalid;
  bool HasKnownValue;
  bool KnownValue;

  friend class Sema;
  ConditionResult(Sema &S, Decl *ConditionVar, FullExprArg Condition,
                  bool IsConstexpr)
      : ConditionVar(ConditionVar), Condition(Condition), Invalid(false),
        HasKnownValue(IsConstexpr && Condition.get() &&
                      !Condition.get()->isValueDependent()),
        KnownValue(HasKnownValue &&
                   !!Condition.get()->EvaluateKnownConstInt(S.Context)) {}
  explicit ConditionResult(bool Invalid)
      : ConditionVar(nullptr), Condition(nullptr), Invalid(Invalid),
        HasKnownValue(false), KnownValue(false) {}

public:
  ConditionResult() : ConditionResult(false) {}
  bool isInvalid() const { return Invalid; }
  std::pair<VarDecl *, Expr *> get() const {
    return std::make_pair(cast_or_null<VarDecl>(ConditionVar),
                          Condition.get());
  }
  llvm::Optional<bool> getKnownValue() const {
    if (!HasKnownValue)
      return None;
    return KnownValue;
  }
};
static ConditionResult ConditionError() { return ConditionResult(true); }

enum class ConditionKind {
  Boolean,     ///< A boolean condition, from 'if', 'while', 'for', or 'do'.
  ConstexprIf, ///< A constant boolean condition from 'if constexpr'.
  Switch       ///< An integral condition for a 'switch' statement.
};

ConditionResult ActOnCondition(Scope *S, SourceLocation Loc,
                               Expr *SubExpr, ConditionKind CK);

ConditionResult ActOnConditionVariable(Decl *ConditionVar,
                                       SourceLocation StmtLoc,
                                       ConditionKind CK);

DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);

ExprResult CheckConditionVariable(VarDecl *ConditionVar,
                                  SourceLocation StmtLoc,
                                  ConditionKind CK);
ExprResult CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond);

/// CheckBooleanCondition - Diagnose problems involving the use of
/// the given expression as a boolean condition (e.g. in an if
/// statement).  Also performs the standard function and array
/// decays, possibly changing the input variable.
///
/// \param Loc - A location associated with the condition, e.g. the
/// 'if' keyword.
/// \return true iff there were any errors
ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E,
                                 bool IsConstexpr = false);

/// ActOnExplicitBoolSpecifier - Build an ExplicitSpecifier from an expression
/// found in an explicit(bool) specifier.
ExplicitSpecifier ActOnExplicitBoolSpecifier(Expr *E);

/// tryResolveExplicitSpecifier - Attempt to resolve the explict specifier.
/// Returns true if the explicit specifier is now resolved.
bool tryResolveExplicitSpecifier(ExplicitSpecifier &ExplicitSpec);

/// DiagnoseAssignmentAsCondition - Given that an expression is
/// being used as a boolean condition, warn if it's an assignment.
void DiagnoseAssignmentAsCondition(Expr *E);

/// Redundant parentheses over an equality comparison can indicate
/// that the user intended an assignment used as condition.
void DiagnoseEqualityWithExtraParens(ParenExpr *ParenE);

/// CheckCXXBooleanCondition - Returns true if conversion to bool is invalid.
ExprResult CheckCXXBooleanCondition(Expr *CondExpr, bool IsConstexpr = false);

/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
/// the specified width and sign.  If an overflow occurs, detect it and emit
/// the specified diagnostic.
void ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &OldVal,
                                        unsigned NewWidth, bool NewSign,
                                        SourceLocation Loc, unsigned DiagID);

/// Checks that the Objective-C declaration is declared in the global scope.
/// Emits an error and marks the declaration as invalid if it's not declared
/// in the global scope.
bool CheckObjCDeclScope(Decl *D);

/// Abstract base class used for diagnosing integer constant
/// expression violations.
class VerifyICEDiagnoser {
public:
  bool Suppress;

  VerifyICEDiagnoser(bool Suppress = false) : Suppress(Suppress) { }

  virtual void diagnoseNotICE(Sema &S, SourceLocation Loc, SourceRange SR) =0;
  virtual void diagnoseFold(Sema &S, SourceLocation Loc, SourceRange SR);
  virtual ~VerifyICEDiagnoser() { }
};

/// VerifyIntegerConstantExpression - Verifies that an expression is an ICE,
/// and reports the appropriate diagnostics. Returns false on success.
/// Can optionally return the value of the expression.
ExprResult VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
                                           VerifyICEDiagnoser &Diagnoser,
                                           bool AllowFold = true);
ExprResult VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
                                           unsigned DiagID,
                                           bool AllowFold = true);
ExprResult VerifyIntegerConstantExpression(Expr *E,
                                           llvm::APSInt *Result = nullptr);

/// VerifyBitField - verifies that a bit field expression is an ICE and has
/// the correct width, and that the field type is valid.
/// Returns false on success.
/// Can optionally return whether the bit-field is of width 0
ExprResult VerifyBitField(SourceLocation FieldLoc, IdentifierInfo *FieldName,
                          QualType FieldTy, bool IsMsStruct,
                          Expr *BitWidth, bool *ZeroWidth = nullptr);

10588private:
unsigned ForceCUDAHostDeviceDepth = 0;

10591public:
/// Increments our count of the number of times we've seen a pragma forcing
/// functions to be __host__ __device__.  So long as this count is greater
/// than zero, all functions encountered will be __host__ __device__.
void PushForceCUDAHostDevice();

/// Decrements our count of the number of times we've seen a pragma forcing
/// functions to be __host__ __device__.  Returns false if the count is 0
/// before incrementing, so you can emit an error.
bool PopForceCUDAHostDevice();

/// Diagnostics that are emitted only if we discover that the given function
/// must be codegen'ed.  Because handling these correctly adds overhead to
/// compilation, this is currently only enabled for CUDA compilations.
llvm::DenseMap<CanonicalDeclPtr<FunctionDecl>,
               std::vector<PartialDiagnosticAt>>
    DeviceDeferredDiags;

/// A pair of a canonical FunctionDecl and a SourceLocation.  When used as the
/// key in a hashtable, both the FD and location are hashed.
struct FunctionDeclAndLoc {
  CanonicalDeclPtr<FunctionDecl> FD;
  SourceLocation Loc;
};

/// FunctionDecls and SourceLocations for which CheckCUDACall has emitted a
/// (maybe deferred) "bad call" diagnostic.  We use this to avoid emitting the
/// same deferred diag twice.
llvm::DenseSet<FunctionDeclAndLoc> LocsWithCUDACallDiags;

/// An inverse call graph, mapping known-emitted functions to one of their
/// known-emitted callers (plus the location of the call).
///
/// Functions that we can tell a priori must be emitted aren't added to this
/// map.
llvm::DenseMap</* Callee = */ CanonicalDeclPtr<FunctionDecl>,
               /* Caller = */ FunctionDeclAndLoc>
    DeviceKnownEmittedFns;

/// A partial call graph maintained during CUDA/OpenMP device code compilation
/// to support deferred diagnostics.
///
/// Functions are only added here if, at the time they're considered, they are
/// not known-emitted.  As soon as we discover that a function is
/// known-emitted, we remove it and everything it transitively calls from this
/// set and add those functions to DeviceKnownEmittedFns.
llvm::DenseMap</* Caller = */ CanonicalDeclPtr<FunctionDecl>,
               /* Callees = */ llvm::MapVector<CanonicalDeclPtr<FunctionDecl>,
                                               SourceLocation>>
    DeviceCallGraph;

/// Diagnostic builder for CUDA/OpenMP devices errors which may or may not be
/// deferred.
///
/// In CUDA, there exist constructs (e.g. variable-length arrays, try/catch)
/// which are not allowed to appear inside __device__ functions and are
/// allowed to appear in __host__ __device__ functions only if the host+device
/// function is never codegen'ed.
///
/// To handle this, we use the notion of "deferred diagnostics", where we
/// attach a diagnostic to a FunctionDecl that's emitted iff it's codegen'ed.
///
/// This class lets you emit either a regular diagnostic, a deferred
/// diagnostic, or no diagnostic at all, according to an argument you pass to
/// its constructor, thus simplifying the process of creating these "maybe
/// deferred" diagnostics.
class DeviceDiagBuilder {
public:
  enum Kind {
    /// Emit no diagnostics.
    K_Nop,
    /// Emit the diagnostic immediately (i.e., behave like Sema::Diag()).
    K_Immediate,
    /// Emit the diagnostic immediately, and, if it's a warning or error, also
    /// emit a call stack showing how this function can be reached by an a
    /// priori known-emitted function.
    K_ImmediateWithCallStack,
    /// Create a deferred diagnostic, which is emitted only if the function
    /// it's attached to is codegen'ed.  Also emit a call stack as with
    /// K_ImmediateWithCallStack.
    K_Deferred
  };

  DeviceDiagBuilder(Kind K, SourceLocation Loc, unsigned DiagID,
                    FunctionDecl *Fn, Sema &S);
  DeviceDiagBuilder(DeviceDiagBuilder &&D);
  DeviceDiagBuilder(const DeviceDiagBuilder &) = default;
  ~DeviceDiagBuilder();

  /// Convertible to bool: True if we immediately emitted an error, false if
  /// we didn't emit an error or we created a deferred error.
  ///
  /// Example usage:
  ///
  ///   if (DeviceDiagBuilder(...) << foo << bar)
  ///     return ExprError();
  ///
  /// But see CUDADiagIfDeviceCode() and CUDADiagIfHostCode() -- you probably
  /// want to use these instead of creating a DeviceDiagBuilder yourself.
  operator bool() const { return ImmediateDiag.hasValue(); }

  template <typename T>
  friend const DeviceDiagBuilder &operator<<(const DeviceDiagBuilder &Diag,
                                             const T &Value) {
    if (Diag.ImmediateDiag.hasValue())
      *Diag.ImmediateDiag << Value;
    else if (Diag.PartialDiagId.hasValue())
      Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second
          << Value;
    return Diag;
  }

private:
  Sema &S;
  SourceLocation Loc;
  unsigned DiagID;
  FunctionDecl *Fn;
  bool ShowCallStack;

  // Invariant: At most one of these Optionals has a value.
  // FIXME: Switch these to a Variant once that exists.
  llvm::Optional<SemaDiagnosticBuilder> ImmediateDiag;
  llvm::Optional<unsigned> PartialDiagId;
};

/// Indicate that this function (and thus everything it transtively calls)
/// will be codegen'ed, and emit any deferred diagnostics on this function and
/// its (transitive) callees.
void markKnownEmitted(
    Sema &S, FunctionDecl *OrigCaller, FunctionDecl *OrigCallee,
    SourceLocation OrigLoc,
    const llvm::function_ref<bool(Sema &, FunctionDecl *)> IsKnownEmitted);

/// Creates a DeviceDiagBuilder that emits the diagnostic if the current context
/// is "used as device code".
///
/// - If CurContext is a __host__ function, does not emit any diagnostics.
/// - If CurContext is a __device__ or __global__ function, emits the
///   diagnostics immediately.
/// - If CurContext is a __host__ __device__ function and we are compiling for
///   the device, creates a diagnostic which is emitted if and when we realize
///   that the function will be codegen'ed.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in CUDA device code.
///  if (CUDADiagIfDeviceCode(Loc, diag::err_cuda_vla) << CurrentCUDATarget())
///    return ExprError();
///  // Otherwise, continue parsing as normal.
DeviceDiagBuilder CUDADiagIfDeviceCode(SourceLocation Loc, unsigned DiagID);

/// Creates a DeviceDiagBuilder that emits the diagnostic if the current context
/// is "used as host code".
///
/// Same as CUDADiagIfDeviceCode, with "host" and "device" switched.
DeviceDiagBuilder CUDADiagIfHostCode(SourceLocation Loc, unsigned DiagID);

/// Creates a DeviceDiagBuilder that emits the diagnostic if the current
/// context is "used as device code".
///
/// - If CurContext is a `declare target` function or it is known that the
/// function is emitted for the device, emits the diagnostics immediately.
/// - If CurContext is a non-`declare target` function and we are compiling
///   for the device, creates a diagnostic which is emitted if and when we
///   realize that the function will be codegen'ed.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in NVPTX device code.
///  if (diagIfOpenMPDeviceCode(Loc, diag::err_vla_unsupported))
///    return ExprError();
///  // Otherwise, continue parsing as normal.
DeviceDiagBuilder diagIfOpenMPDeviceCode(SourceLocation Loc, unsigned DiagID);

/// Creates a DeviceDiagBuilder that emits the diagnostic if the current
/// context is "used as host code".
///
/// - If CurContext is a `declare target` function or it is known that the
/// function is emitted for the host, emits the diagnostics immediately.
/// - If CurContext is a non-host function, just ignore it.
///
/// Example usage:
///
///  // Variable-length arrays are not allowed in NVPTX device code.
///  if (diagIfOpenMPHostode(Loc, diag::err_vla_unsupported))
///    return ExprError();
///  // Otherwise, continue parsing as normal.
DeviceDiagBuilder diagIfOpenMPHostCode(SourceLocation Loc, unsigned DiagID);

DeviceDiagBuilder targetDiag(SourceLocation Loc, unsigned DiagID);

enum CUDAFunctionTarget {
  CFT_Device,
  CFT_Global,
  CFT_Host,
  CFT_HostDevice,
  CFT_InvalidTarget
};

/// Determines whether the given function is a CUDA device/host/kernel/etc.
/// function.
///
/// Use this rather than examining the function's attributes yourself -- you
/// will get it wrong.  Returns CFT_Host if D is null.
CUDAFunctionTarget IdentifyCUDATarget(const FunctionDecl *D,
                                      bool IgnoreImplicitHDAttr = false);
CUDAFunctionTarget IdentifyCUDATarget(const ParsedAttributesView &Attrs);

/// Gets the CUDA target for the current context.
CUDAFunctionTarget CurrentCUDATarget() {
  return IdentifyCUDATarget(dyn_cast<FunctionDecl>(CurContext));
}

// CUDA function call preference. Must be ordered numerically from
// worst to best.
enum CUDAFunctionPreference {
  CFP_Never,      // Invalid caller/callee combination.
  CFP_WrongSide,  // Calls from host-device to host or device
                  // function that do not match current compilation
                  // mode.
  CFP_HostDevice, // Any calls to host/device functions.
  CFP_SameSide,   // Calls from host-device to host or device
                  // function matching current compilation mode.
  CFP_Native,     // host-to-host or device-to-device calls.
};

/// Identifies relative preference of a given Caller/Callee
/// combination, based on their host/device attributes.
/// \param Caller function which needs address of \p Callee.
///               nullptr in case of global context.
/// \param Callee target function
///
/// \returns preference value for particular Caller/Callee combination.
CUDAFunctionPreference IdentifyCUDAPreference(const FunctionDecl *Caller,
                                              const FunctionDecl *Callee);

/// Determines whether Caller may invoke Callee, based on their CUDA
/// host/device attributes.  Returns false if the call is not allowed.
///
/// Note: Will return true for CFP_WrongSide calls.  These may appear in
/// semantically correct CUDA programs, but only if they're never codegen'ed.
bool IsAllowedCUDACall(const FunctionDecl *Caller,
                       const FunctionDecl *Callee) {
  return IdentifyCUDAPreference(Caller, Callee) != CFP_Never;
}

/// May add implicit CUDAHostAttr and CUDADeviceAttr attributes to FD,
/// depending on FD and the current compilation settings.
void maybeAddCUDAHostDeviceAttrs(FunctionDecl *FD,
                                 const LookupResult &Previous);

10842public:
/// Check whether we're allowed to call Callee from the current context.
///
/// - If the call is never allowed in a semantically-correct program
///   (CFP_Never), emits an error and returns false.
///
/// - If the call is allowed in semantically-correct programs, but only if
///   it's never codegen'ed (CFP_WrongSide), creates a deferred diagnostic to
///   be emitted if and when the caller is codegen'ed, and returns true.
///
///   Will only create deferred diagnostics for a given SourceLocation once,
///   so you can safely call this multiple times without generating duplicate
///   deferred errors.
///
/// - Otherwise, returns true without emitting any diagnostics.
bool CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee);

/// Set __device__ or __host__ __device__ attributes on the given lambda
/// operator() method.
///
/// CUDA lambdas declared inside __device__ or __global__ functions inherit
/// the __device__ attribute.  Similarly, lambdas inside __host__ __device__
/// functions become __host__ __device__ themselves.
void CUDASetLambdaAttrs(CXXMethodDecl *Method);

/// Finds a function in \p Matches with highest calling priority
/// from \p Caller context and erases all functions with lower
/// calling priority.
void EraseUnwantedCUDAMatches(
    const FunctionDecl *Caller,
    SmallVectorImpl<std::pair<DeclAccessPair, FunctionDecl *>> &Matches);

/// Given a implicit special member, infer its CUDA target from the
/// calls it needs to make to underlying base/field special members.
/// \param ClassDecl the class for which the member is being created.
/// \param CSM the kind of special member.
/// \param MemberDecl the special member itself.
/// \param ConstRHS true if this is a copy operation with a const object on
///        its RHS.
/// \param Diagnose true if this call should emit diagnostics.
/// \return true if there was an error inferring.
/// The result of this call is implicit CUDA target attribute(s) attached to
/// the member declaration.
bool inferCUDATargetForImplicitSpecialMember(CXXRecordDecl *ClassDecl,
                                             CXXSpecialMember CSM,
                                             CXXMethodDecl *MemberDecl,
                                             bool ConstRHS,
                                             bool Diagnose);

/// \return true if \p CD can be considered empty according to CUDA
/// (E.2.3.1 in CUDA 7.5 Programming guide).
bool isEmptyCudaConstructor(SourceLocation Loc, CXXConstructorDecl *CD);
bool isEmptyCudaDestructor(SourceLocation Loc, CXXDestructorDecl *CD);

// \brief Checks that initializers of \p Var satisfy CUDA restrictions. In
// case of error emits appropriate diagnostic and invalidates \p Var.
//
// \details CUDA allows only empty constructors as initializers for global
// variables (see E.2.3.1, CUDA 7.5). The same restriction also applies to all
// __shared__ variables whether they are local or not (they all are implicitly
// static in CUDA). One exception is that CUDA allows constant initializers
// for __constant__ and __device__ variables.
void checkAllowedCUDAInitializer(VarDecl *VD);

/// Check whether NewFD is a valid overload for CUDA. Emits
/// diagnostics and invalidates NewFD if not.
void checkCUDATargetOverload(FunctionDecl *NewFD,
                             const LookupResult &Previous);
/// Copies target attributes from the template TD to the function FD.
void inheritCUDATargetAttrs(FunctionDecl *FD, const FunctionTemplateDecl &TD);

/// Returns the name of the launch configuration function.  This is the name
/// of the function that will be called to configure kernel call, with the
/// parameters specified via <<<>>>.
std::string getCudaConfigureFuncName() const;

/// \name Code completion
//@{
/// Describes the context in which code completion occurs.
enum ParserCompletionContext {
  /// Code completion occurs at top-level or namespace context.
  PCC_Namespace,
  /// Code completion occurs within a class, struct, or union.
  PCC_Class,
  /// Code completion occurs within an Objective-C interface, protocol,
  /// or category.
  PCC_ObjCInterface,
  /// Code completion occurs within an Objective-C implementation or
  /// category implementation
  PCC_ObjCImplementation,
  /// Code completion occurs within the list of instance variables
  /// in an Objective-C interface, protocol, category, or implementation.
  PCC_ObjCInstanceVariableList,
  /// Code completion occurs following one or more template
  /// headers.
  PCC_Template,
  /// Code completion occurs following one or more template
  /// headers within a class.
  PCC_MemberTemplate,
  /// Code completion occurs within an expression.
  PCC_Expression,
  /// Code completion occurs within a statement, which may
  /// also be an expression or a declaration.
  PCC_Statement,
  /// Code completion occurs at the beginning of the
  /// initialization statement (or expression) in a for loop.
  PCC_ForInit,
  /// Code completion occurs within the condition of an if,
  /// while, switch, or for statement.
  PCC_Condition,
  /// Code completion occurs within the body of a function on a
  /// recovery path, where we do not have a specific handle on our position
  /// in the grammar.
  PCC_RecoveryInFunction,
  /// Code completion occurs where only a type is permitted.
  PCC_Type,
  /// Code completion occurs in a parenthesized expression, which
  /// might also be a type cast.
  PCC_ParenthesizedExpression,
  /// Code completion occurs within a sequence of declaration
  /// specifiers within a function, method, or block.
  PCC_LocalDeclarationSpecifiers
};

void CodeCompleteModuleImport(SourceLocation ImportLoc, ModuleIdPath Path);
void CodeCompleteOrdinaryName(Scope *S,
                              ParserCompletionContext CompletionContext);
void CodeCompleteDeclSpec(Scope *S, DeclSpec &DS,
                          bool AllowNonIdentifiers,
                          bool AllowNestedNameSpecifiers);

struct CodeCompleteExpressionData;
void CodeCompleteExpression(Scope *S,
                            const CodeCompleteExpressionData &Data);
void CodeCompleteExpression(Scope *S, QualType PreferredType,
                            bool IsParenthesized = false);
void CodeCompleteMemberReferenceExpr(Scope *S, Expr *Base, Expr *OtherOpBase,
                                     SourceLocation OpLoc, bool IsArrow,
                                     bool IsBaseExprStatement,
                                     QualType PreferredType);
void CodeCompletePostfixExpression(Scope *S, ExprResult LHS,
                                   QualType PreferredType);
void CodeCompleteTag(Scope *S, unsigned TagSpec);
void CodeCompleteTypeQualifiers(DeclSpec &DS);
void CodeCompleteFunctionQualifiers(DeclSpec &DS, Declarator &D,
                                    const VirtSpecifiers *VS = nullptr);
void CodeCompleteBracketDeclarator(Scope *S);
void CodeCompleteCase(Scope *S);
/// Reports signatures for a call to CodeCompleteConsumer and returns the
/// preferred type for the current argument. Returned type can be null.
QualType ProduceCallSignatureHelp(Scope *S, Expr *Fn, ArrayRef<Expr *> Args,
                                  SourceLocation OpenParLoc);
QualType ProduceConstructorSignatureHelp(Scope *S, QualType Type,
                                         SourceLocation Loc,
                                         ArrayRef<Expr *> Args,
                                         SourceLocation OpenParLoc);
QualType ProduceCtorInitMemberSignatureHelp(Scope *S, Decl *ConstructorDecl,
                                            CXXScopeSpec SS,
                                            ParsedType TemplateTypeTy,
                                            ArrayRef<Expr *> ArgExprs,
                                            IdentifierInfo *II,
                                            SourceLocation OpenParLoc);
void CodeCompleteInitializer(Scope *S, Decl *D);
void CodeCompleteAfterIf(Scope *S);

void CodeCompleteQualifiedId(Scope *S, CXXScopeSpec &SS, bool EnteringContext,
                             QualType BaseType, QualType PreferredType);
void CodeCompleteUsing(Scope *S);
void CodeCompleteUsingDirective(Scope *S);
void CodeCompleteNamespaceDecl(Scope *S);
void CodeCompleteNamespaceAliasDecl(Scope *S);
void CodeCompleteOperatorName(Scope *S);
void CodeCompleteConstructorInitializer(
                              Decl *Constructor,
                              ArrayRef<CXXCtorInitializer *> Initializers);

void CodeCompleteLambdaIntroducer(Scope *S, LambdaIntroducer &Intro,
                                  bool AfterAmpersand);

void CodeCompleteObjCAtDirective(Scope *S);
void CodeCompleteObjCAtVisibility(Scope *S);
void CodeCompleteObjCAtStatement(Scope *S);
void CodeCompleteObjCAtExpression(Scope *S);
void CodeCompleteObjCPropertyFlags(Scope *S, ObjCDeclSpec &ODS);
void CodeCompleteObjCPropertyGetter(Scope *S);
void CodeCompleteObjCPropertySetter(Scope *S);
void CodeCompleteObjCPassingType(Scope *S, ObjCDeclSpec &DS,
                                 bool IsParameter);
void CodeCompleteObjCMessageReceiver(Scope *S);
void CodeCompleteObjCSuperMessage(Scope *S, SourceLocation SuperLoc,
                                  ArrayRef<IdentifierInfo *> SelIdents,
                                  bool AtArgumentExpression);
void CodeCompleteObjCClassMessage(Scope *S, ParsedType Receiver,
                                  ArrayRef<IdentifierInfo *> SelIdents,
                                  bool AtArgumentExpression,
                                  bool IsSuper = false);
void CodeCompleteObjCInstanceMessage(Scope *S, Expr *Receiver,
                                     ArrayRef<IdentifierInfo *> SelIdents,
                                     bool AtArgumentExpression,
                                     ObjCInterfaceDecl *Super = nullptr);
void CodeCompleteObjCForCollection(Scope *S,
                                   DeclGroupPtrTy IterationVar);
void CodeCompleteObjCSelector(Scope *S,
                              ArrayRef<IdentifierInfo *> SelIdents);
void CodeCompleteObjCProtocolReferences(
                                       ArrayRef<IdentifierLocPair> Protocols);
void CodeCompleteObjCProtocolDecl(Scope *S);
void CodeCompleteObjCInterfaceDecl(Scope *S);
void CodeCompleteObjCSuperclass(Scope *S,
                                IdentifierInfo *ClassName,
                                SourceLocation ClassNameLoc);
void CodeCompleteObjCImplementationDecl(Scope *S);
void CodeCompleteObjCInterfaceCategory(Scope *S,
                                       IdentifierInfo *ClassName,
                                       SourceLocation ClassNameLoc);
void CodeCompleteObjCImplementationCategory(Scope *S,
                                            IdentifierInfo *ClassName,
                                            SourceLocation ClassNameLoc);
void CodeCompleteObjCPropertyDefinition(Scope *S);
void CodeCompleteObjCPropertySynthesizeIvar(Scope *S,
                                            IdentifierInfo *PropertyName);
void CodeCompleteObjCMethodDecl(Scope *S, Optional<bool> IsInstanceMethod,
                                ParsedType ReturnType);
void CodeCompleteObjCMethodDeclSelector(Scope *S,
                                        bool IsInstanceMethod,
                                        bool AtParameterName,
                                        ParsedType ReturnType,
                                        ArrayRef<IdentifierInfo *> SelIdents);
void CodeCompleteObjCClassPropertyRefExpr(Scope *S, IdentifierInfo &ClassName,
                                          SourceLocation ClassNameLoc,
                                          bool IsBaseExprStatement);
void CodeCompletePreprocessorDirective(bool InConditional);
void CodeCompleteInPreprocessorConditionalExclusion(Scope *S);
void CodeCompletePreprocessorMacroName(bool IsDefinition);
void CodeCompletePreprocessorExpression();
void CodeCompletePreprocessorMacroArgument(Scope *S,
                                           IdentifierInfo *Macro,
                                           MacroInfo *MacroInfo,
                                           unsigned Argument);
void CodeCompleteIncludedFile(llvm::StringRef Dir, bool IsAngled);
void CodeCompleteNaturalLanguage();
void CodeCompleteAvailabilityPlatformName();
void GatherGlobalCodeCompletions(CodeCompletionAllocator &Allocator,
                                 CodeCompletionTUInfo &CCTUInfo,
                SmallVectorImpl<CodeCompletionResult> &Results);
//@}

//===--------------------------------------------------------------------===//
// Extra semantic analysis beyond the C type system

11092public:
SourceLocation getLocationOfStringLiteralByte(const StringLiteral *SL,
                                              unsigned ByteNo) const;

11096private:
void CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
                      const ArraySubscriptExpr *ASE=nullptr,
                      bool AllowOnePastEnd=true, bool IndexNegated=false);
void CheckArrayAccess(const Expr *E);
// Used to grab the relevant information from a FormatAttr and a
// FunctionDeclaration.
struct FormatStringInfo {
  unsigned FormatIdx;
  unsigned FirstDataArg;
  bool HasVAListArg;
};

static bool getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
                                FormatStringInfo *FSI);
bool CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
                       const FunctionProtoType *Proto);
bool CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation loc,
                         ArrayRef<const Expr *> Args);
bool CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall,
                      const FunctionProtoType *Proto);
bool CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto);
void CheckConstructorCall(FunctionDecl *FDecl,
                          ArrayRef<const Expr *> Args,
                          const FunctionProtoType *Proto,
                          SourceLocation Loc);

void checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
               const Expr *ThisArg, ArrayRef<const Expr *> Args,
               bool IsMemberFunction, SourceLocation Loc, SourceRange Range,
               VariadicCallType CallType);

bool CheckObjCString(Expr *Arg);
ExprResult CheckOSLogFormatStringArg(Expr *Arg);

ExprResult CheckBuiltinFunctionCall(FunctionDecl *FDecl,
                                    unsigned BuiltinID, CallExpr *TheCall);
void checkFortifiedBuiltinMemoryFunction(FunctionDecl *FD, CallExpr *TheCall);

bool CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall,
                                  unsigned MaxWidth);
bool CheckNeonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);

bool CheckAArch64BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckBPFBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckHexagonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckHexagonBuiltinCpu(unsigned BuiltinID, CallExpr *TheCall);
bool CheckHexagonBuiltinArgument(unsigned BuiltinID, CallExpr *TheCall);
bool CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckSystemZBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinRoundingOrSAE(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinGatherScatterScale(unsigned BuiltinID, CallExpr *TheCall);
bool CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
bool CheckPPCBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);

bool SemaBuiltinVAStart(unsigned BuiltinID, CallExpr *TheCall);
bool SemaBuiltinVAStartARMMicrosoft(CallExpr *Call);
bool SemaBuiltinUnorderedCompare(CallExpr *TheCall);
bool SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs);
bool SemaBuiltinVSX(CallExpr *TheCall);
bool SemaBuiltinOSLogFormat(CallExpr *TheCall);

11159public:
// Used by C++ template instantiation.
ExprResult SemaBuiltinShuffleVector(CallExpr *TheCall);
ExprResult SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo,
                                 SourceLocation BuiltinLoc,
                                 SourceLocation RParenLoc);

11166private:
bool SemaBuiltinPrefetch(CallExpr *TheCall);
bool SemaBuiltinAllocaWithAlign(CallExpr *TheCall);
bool SemaBuiltinAssume(CallExpr *TheCall);
bool SemaBuiltinAssumeAligned(CallExpr *TheCall);
bool SemaBuiltinLongjmp(CallExpr *TheCall);
bool SemaBuiltinSetjmp(CallExpr *TheCall);
ExprResult SemaBuiltinAtomicOverloaded(ExprResult TheCallResult);
ExprResult SemaBuiltinNontemporalOverloaded(ExprResult TheCallResult);
ExprResult SemaAtomicOpsOverloaded(ExprResult TheCallResult,
                                   AtomicExpr::AtomicOp Op);
ExprResult SemaBuiltinOperatorNewDeleteOverloaded(ExprResult TheCallResult,
                                                  bool IsDelete);
bool SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
                            llvm::APSInt &Result);
bool SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum, int Low,
                                 int High, bool RangeIsError = true);
bool SemaBuiltinConstantArgMultiple(CallExpr *TheCall, int ArgNum,
                                    unsigned Multiple);
bool SemaBuiltinARMSpecialReg(unsigned BuiltinID, CallExpr *TheCall,
                              int ArgNum, unsigned ExpectedFieldNum,
                              bool AllowName);
bool SemaBuiltinARMMemoryTaggingCall(unsigned BuiltinID, CallExpr *TheCall);
11189public:
enum FormatStringType {
  FST_Scanf,
  FST_Printf,
  FST_NSString,
  FST_Strftime,
  FST_Strfmon,
  FST_Kprintf,
  FST_FreeBSDKPrintf,
  FST_OSTrace,
  FST_OSLog,
  FST_Unknown
};
static FormatStringType GetFormatStringType(const FormatAttr *Format);

bool FormatStringHasSArg(const StringLiteral *FExpr);

static bool GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx);

11208private:
bool CheckFormatArguments(const FormatAttr *Format,
                          ArrayRef<const Expr *> Args,
                          bool IsCXXMember,
                          VariadicCallType CallType,
                          SourceLocation Loc, SourceRange Range,
                          llvm::SmallBitVector &CheckedVarArgs);
bool CheckFormatArguments(ArrayRef<const Expr *> Args,
                          bool HasVAListArg, unsigned format_idx,
                          unsigned firstDataArg, FormatStringType Type,
                          VariadicCallType CallType,
                          SourceLocation Loc, SourceRange range,
                          llvm::SmallBitVector &CheckedVarArgs);

void CheckAbsoluteValueFunction(const CallExpr *Call,
                                const FunctionDecl *FDecl);

void CheckMaxUnsignedZero(const CallExpr *Call, const FunctionDecl *FDecl);

void CheckMemaccessArguments(const CallExpr *Call,
                             unsigned BId,
                             IdentifierInfo *FnName);

void CheckStrlcpycatArguments(const CallExpr *Call,
                              IdentifierInfo *FnName);

void CheckStrncatArguments(const CallExpr *Call,
                           IdentifierInfo *FnName);

void CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
                        SourceLocation ReturnLoc,
                        bool isObjCMethod = false,
                        const AttrVec *Attrs = nullptr,
                        const FunctionDecl *FD = nullptr);

11243public:
void CheckFloatComparison(SourceLocation Loc, Expr *LHS, Expr *RHS);

11246private:
void CheckImplicitConversions(Expr *E, SourceLocation CC = SourceLocation());
void CheckBoolLikeConversion(Expr *E, SourceLocation CC);
void CheckForIntOverflow(Expr *E);
void CheckUnsequencedOperations(Expr *E);

/// Perform semantic checks on a completed expression. This will either
/// be a full-expression or a default argument expression.
void CheckCompletedExpr(Expr *E, SourceLocation CheckLoc = SourceLocation(),
                        bool IsConstexpr = false);

void CheckBitFieldInitialization(SourceLocation InitLoc, FieldDecl *Field,
                                 Expr *Init);

/// Check if there is a field shadowing.
void CheckShadowInheritedFields(const SourceLocation &Loc,
                                DeclarationName FieldName,
                                const CXXRecordDecl *RD,
                                bool DeclIsField = true);

/// Check if the given expression contains 'break' or 'continue'
/// statement that produces control flow different from GCC.
void CheckBreakContinueBinding(Expr *E);

/// Check whether receiver is mutable ObjC container which
/// attempts to add itself into the container
void CheckObjCCircularContainer(ObjCMessageExpr *Message);

void AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE);
void AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
                               bool DeleteWasArrayForm);
11277public:
/// Register a magic integral constant to be used as a type tag.
void RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
                                uint64_t MagicValue, QualType Type,
                                bool LayoutCompatible, bool MustBeNull);

struct TypeTagData {
  TypeTagData() {}

  TypeTagData(QualType Type, bool LayoutCompatible, bool MustBeNull) :
      Type(Type), LayoutCompatible(LayoutCompatible),
      MustBeNull(MustBeNull)
  {}

  QualType Type;

  /// If true, \c Type should be compared with other expression's types for
  /// layout-compatibility.
  unsigned LayoutCompatible : 1;
  unsigned MustBeNull : 1;
};

/// A pair of ArgumentKind identifier and magic value.  This uniquely
/// identifies the magic value.
typedef std::pair<const IdentifierInfo *, uint64_t> TypeTagMagicValue;

11303private:
/// A map from magic value to type information.
std::unique_ptr<llvm::DenseMap<TypeTagMagicValue, TypeTagData>>
    TypeTagForDatatypeMagicValues;

/// Peform checks on a call of a function with argument_with_type_tag
/// or pointer_with_type_tag attributes.
void CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
                              const ArrayRef<const Expr *> ExprArgs,
                              SourceLocation CallSiteLoc);

/// Check if we are taking the address of a packed field
/// as this may be a problem if the pointer value is dereferenced.
void CheckAddressOfPackedMember(Expr *rhs);

/// The parser's current scope.
///
/// The parser maintains this state here.
Scope *CurScope;

mutable IdentifierInfo *Ident_super;
mutable IdentifierInfo *Ident___float128;

/// Nullability type specifiers.
IdentifierInfo *Ident__Nonnull = nullptr;
IdentifierInfo *Ident__Nullable = nullptr;
IdentifierInfo *Ident__Null_unspecified = nullptr;

IdentifierInfo *Ident_NSError = nullptr;

/// The handler for the FileChanged preprocessor events.
///
/// Used for diagnostics that implement custom semantic analysis for #include
/// directives, like -Wpragma-pack.
sema::SemaPPCallbacks *SemaPPCallbackHandler;

11339protected:
friend class Parser;
friend class InitializationSequence;
friend class ASTReader;
friend class ASTDeclReader;
friend class ASTWriter;

11346public:
/// Retrieve the keyword associated
IdentifierInfo *getNullabilityKeyword(NullabilityKind nullability);

/// The struct behind the CFErrorRef pointer.
RecordDecl *CFError = nullptr;

/// Retrieve the identifier "NSError".
IdentifierInfo *getNSErrorIdent();

/// Retrieve the parser's current scope.
///
/// This routine must only be used when it is certain that semantic analysis
/// and the parser are in precisely the same context, which is not the case
/// when, e.g., we are performing any kind of template instantiation.
/// Therefore, the only safe places to use this scope are in the parser
/// itself and in routines directly invoked from the parser and *never* from
/// template substitution or instantiation.
Scope *getCurScope() const { return CurScope; }

void incrementMSManglingNumber() const {
  return CurScope->incrementMSManglingNumber();
}

IdentifierInfo *getSuperIdentifier() const;
IdentifierInfo *getFloat128Identifier() const;

Decl *getObjCDeclContext() const;

DeclContext *getCurLexicalContext() const {
  return OriginalLexicalContext ? OriginalLexicalContext : CurContext;
}

const DeclContext *getCurObjCLexicalContext() const {
  const DeclContext *DC = getCurLexicalContext();
  // A category implicitly has the attribute of the interface.
  if (const ObjCCategoryDecl *CatD = dyn_cast<ObjCCategoryDecl>(DC))
    DC = CatD->getClassInterface();
  return DC;
}

/// To be used for checking whether the arguments being passed to
/// function exceeds the number of parameters expected for it.
static bool TooManyArguments(size_t NumParams, size_t NumArgs,
                             bool PartialOverloading = false) {
  // We check whether we're just after a comma in code-completion.
  if (NumArgs > 0 && PartialOverloading)
5
←
Assuming 'NumArgs' is > 0→
6
←
Assuming 'PartialOverloading' is false→
7
←
Taking false branch→
    return NumArgs + 1 > NumParams; // If so, we view as an extra argument.
  return NumArgs > NumParams;
8
←
Assuming 'NumArgs' is > 'NumParams'→
9
←
Returning the value 1, which participates in a condition later→
}

// Emitting members of dllexported classes is delayed until the class
// (including field initializers) is fully parsed.
SmallVector<CXXRecordDecl*, 4> DelayedDllExportClasses;
SmallVector<CXXMethodDecl*, 4> DelayedDllExportMemberFunctions;

11402private:
class SavePendingParsedClassStateRAII {
public:
  SavePendingParsedClassStateRAII(Sema &S) : S(S) { swapSavedState(); }

  ~SavePendingParsedClassStateRAII() {
    assert(S.DelayedOverridingExceptionSpecChecks.empty() &&((S.DelayedOverridingExceptionSpecChecks.empty() && "there shouldn't be any pending delayed exception spec checks"
) ? static_cast<void> (0) : __assert_fail ("S.DelayedOverridingExceptionSpecChecks.empty() && \"there shouldn't be any pending delayed exception spec checks\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 11409, __PRETTY_FUNCTION__))
           "there shouldn't be any pending delayed exception spec checks")((S.DelayedOverridingExceptionSpecChecks.empty() && "there shouldn't be any pending delayed exception spec checks"
) ? static_cast<void> (0) : __assert_fail ("S.DelayedOverridingExceptionSpecChecks.empty() && \"there shouldn't be any pending delayed exception spec checks\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 11409, __PRETTY_FUNCTION__));
    assert(S.DelayedEquivalentExceptionSpecChecks.empty() &&((S.DelayedEquivalentExceptionSpecChecks.empty() && "there shouldn't be any pending delayed exception spec checks"
) ? static_cast<void> (0) : __assert_fail ("S.DelayedEquivalentExceptionSpecChecks.empty() && \"there shouldn't be any pending delayed exception spec checks\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 11411, __PRETTY_FUNCTION__))
           "there shouldn't be any pending delayed exception spec checks")((S.DelayedEquivalentExceptionSpecChecks.empty() && "there shouldn't be any pending delayed exception spec checks"
) ? static_cast<void> (0) : __assert_fail ("S.DelayedEquivalentExceptionSpecChecks.empty() && \"there shouldn't be any pending delayed exception spec checks\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 11411, __PRETTY_FUNCTION__));
    assert(S.DelayedDllExportClasses.empty() &&((S.DelayedDllExportClasses.empty() && "there shouldn't be any pending delayed DLL export classes"
) ? static_cast<void> (0) : __assert_fail ("S.DelayedDllExportClasses.empty() && \"there shouldn't be any pending delayed DLL export classes\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 11413, __PRETTY_FUNCTION__))
           "there shouldn't be any pending delayed DLL export classes")((S.DelayedDllExportClasses.empty() && "there shouldn't be any pending delayed DLL export classes"
) ? static_cast<void> (0) : __assert_fail ("S.DelayedDllExportClasses.empty() && \"there shouldn't be any pending delayed DLL export classes\""
, "/build/llvm-toolchain-snapshot-10~svn374877/tools/clang/include/clang/Sema/Sema.h"
, 11413, __PRETTY_FUNCTION__));
    swapSavedState();
  }

private:
  Sema &S;
  decltype(DelayedOverridingExceptionSpecChecks)
      SavedOverridingExceptionSpecChecks;
  decltype(DelayedEquivalentExceptionSpecChecks)
      SavedEquivalentExceptionSpecChecks;
  decltype(DelayedDllExportClasses) SavedDllExportClasses;

  void swapSavedState() {
    SavedOverridingExceptionSpecChecks.swap(
        S.DelayedOverridingExceptionSpecChecks);
    SavedEquivalentExceptionSpecChecks.swap(
        S.DelayedEquivalentExceptionSpecChecks);
    SavedDllExportClasses.swap(S.DelayedDllExportClasses);
  }
};

/// Helper class that collects misaligned member designations and
/// their location info for delayed diagnostics.
struct MisalignedMember {
  Expr *E;
  RecordDecl *RD;
  ValueDecl *MD;
  CharUnits Alignment;

  MisalignedMember() : E(), RD(), MD(), Alignment() {}
  MisalignedMember(Expr *E, RecordDecl *RD, ValueDecl *MD,
                   CharUnits Alignment)
      : E(E), RD(RD), MD(MD), Alignment(Alignment) {}
  explicit MisalignedMember(Expr *E)
      : MisalignedMember(E, nullptr, nullptr, CharUnits()) {}

  bool operator==(const MisalignedMember &m) { return this->E == m.E; }
};
/// Small set of gathered accesses to potentially misaligned members
/// due to the packed attribute.
SmallVector<MisalignedMember, 4> MisalignedMembers;

/// Adds an expression to the set of gathered misaligned members.
void AddPotentialMisalignedMembers(Expr *E, RecordDecl *RD, ValueDecl *MD,
                                   CharUnits Alignment);

11459public:
/// Diagnoses the current set of gathered accesses. This typically
/// happens at full expression level. The set is cleared after emitting the
/// diagnostics.
void DiagnoseMisalignedMembers();

/// This function checks if the expression is in the sef of potentially
/// misaligned members and it is converted to some pointer type T with lower
/// or equal alignment requirements. If so it removes it. This is used when
/// we do not want to diagnose such misaligned access (e.g. in conversions to
/// void*).
void DiscardMisalignedMemberAddress(const Type *T, Expr *E);

/// This function calls Action when it determines that E designates a
/// misaligned member due to the packed attribute. This is used to emit
/// local diagnostics like in reference binding.
void RefersToMemberWithReducedAlignment(
    Expr *E,
    llvm::function_ref<void(Expr *, RecordDecl *, FieldDecl *, CharUnits)>
        Action);

/// Describes the reason a calling convention specification was ignored, used
/// for diagnostics.
enum class CallingConventionIgnoredReason {
  ForThisTarget = 0,
  VariadicFunction,
  ConstructorDestructor,
  BuiltinFunction
};
11488};

11490/// RAII object that enters a new expression evaluation context.
11491class EnterExpressionEvaluationContext {
Sema &Actions;
bool Entered = true;

11495public:
EnterExpressionEvaluationContext(
    Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
    Decl *LambdaContextDecl = nullptr,
    Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
        Sema::ExpressionEvaluationContextRecord::EK_Other,
    bool ShouldEnter = true)
    : Actions(Actions), Entered(ShouldEnter) {
  if (Entered)
    Actions.PushExpressionEvaluationContext(NewContext, LambdaContextDecl,
                                            ExprContext);
}
EnterExpressionEvaluationContext(
    Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
    Sema::ReuseLambdaContextDecl_t,
    Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
        Sema::ExpressionEvaluationContextRecord::EK_Other)
    : Actions(Actions) {
  Actions.PushExpressionEvaluationContext(
      NewContext, Sema::ReuseLambdaContextDecl, ExprContext);
}

enum InitListTag { InitList };
EnterExpressionEvaluationContext(Sema &Actions, InitListTag,
                                 bool ShouldEnter = true)
    : Actions(Actions), Entered(false) {
  // In C++11 onwards, narrowing checks are performed on the contents of
  // braced-init-lists, even when they occur within unevaluated operands.
  // Therefore we still need to instantiate constexpr functions used in such
  // a context.
  if (ShouldEnter && Actions.isUnevaluatedContext() &&
      Actions.getLangOpts().CPlusPlus11) {
    Actions.PushExpressionEvaluationContext(
        Sema::ExpressionEvaluationContext::UnevaluatedList);
    Entered = true;
  }
}

~EnterExpressionEvaluationContext() {
  if (Entered)
    Actions.PopExpressionEvaluationContext();
}
11537};

11539DeductionFailureInfo
11540MakeDeductionFailureInfo(ASTContext &Context, Sema::TemplateDeductionResult TDK,
                       sema::TemplateDeductionInfo &Info);

11543/// Contains a late templated function.
11544/// Will be parsed at the end of the translation unit, used by Sema & Parser.
11545struct LateParsedTemplate {
CachedTokens Toks;
/// The template function declaration to be late parsed.
Decl *D;
11549};
11550} // end namespace clang

11552namespace llvm {
11553// Hash a FunctionDeclAndLoc by looking at both its FunctionDecl and its
11554// SourceLocation.
11555template <> struct DenseMapInfo<clang::Sema::FunctionDeclAndLoc> {
using FunctionDeclAndLoc = clang::Sema::FunctionDeclAndLoc;
using FDBaseInfo = DenseMapInfo<clang::CanonicalDeclPtr<clang::FunctionDecl>>;

static FunctionDeclAndLoc getEmptyKey() {
  return {FDBaseInfo::getEmptyKey(), clang::SourceLocation()};
}

static FunctionDeclAndLoc getTombstoneKey() {
  return {FDBaseInfo::getTombstoneKey(), clang::SourceLocation()};
}

static unsigned getHashValue(const FunctionDeclAndLoc &FDL) {
  return hash_combine(FDBaseInfo::getHashValue(FDL.FD),
                      FDL.Loc.getRawEncoding());
}

static bool isEqual(const FunctionDeclAndLoc &LHS,
                    const FunctionDeclAndLoc &RHS) {
  return LHS.FD == RHS.FD && LHS.Loc == RHS.Loc;
}
11576};
11577} // namespace llvm

11579#endif