/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/clang/lib/Sema/SemaTemplateInstantiate.cpp

Bug Summary

File:	build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/clang/lib/Sema/SemaTemplateInstantiate.cpp
Warning:	line 1020, column 15 Called C++ object pointer is null
Annotated Source Code

Press '?' to see keyboard shortcuts
Show analyzer invocation
clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name SemaTemplateInstantiate.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/build-llvm -resource-dir /usr/lib/llvm-15/lib/clang/15.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/clang/lib/Sema -I /build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/clang/include -I tools/clang/include -I include -I /build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-15/lib/clang/15.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/build-llvm=build-llvm -fmacro-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/build-llvm=build-llvm -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/= -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/build-llvm=build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-04-20-140412-16051-1 -x c++ /build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/clang/lib/Sema/SemaTemplateInstantiate.cpp
1//===------- SemaTemplateInstantiate.cpp - C++ Template Instantiation ------===/
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//  This file implements C++ template instantiation.
9//
10//===----------------------------------------------------------------------===/

12#include "TreeTransform.h"
13#include "clang/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/ASTLambda.h"
16#include "clang/AST/ASTMutationListener.h"
17#include "clang/AST/DeclTemplate.h"
18#include "clang/AST/Expr.h"
19#include "clang/AST/PrettyDeclStackTrace.h"
20#include "clang/AST/TypeVisitor.h"
21#include "clang/Basic/LangOptions.h"
22#include "clang/Basic/Stack.h"
23#include "clang/Basic/TargetInfo.h"
24#include "clang/Sema/DeclSpec.h"
25#include "clang/Sema/Initialization.h"
26#include "clang/Sema/Lookup.h"
27#include "clang/Sema/SemaConcept.h"
28#include "clang/Sema/SemaInternal.h"
29#include "clang/Sema/Template.h"
30#include "clang/Sema/TemplateDeduction.h"
31#include "clang/Sema/TemplateInstCallback.h"
32#include "llvm/Support/TimeProfiler.h"

34using namespace clang;
35using namespace sema;

37//===----------------------------------------------------------------------===/
38// Template Instantiation Support
39//===----------------------------------------------------------------------===/

41/// Retrieve the template argument list(s) that should be used to
42/// instantiate the definition of the given declaration.
43///
44/// \param D the declaration for which we are computing template instantiation
45/// arguments.
46///
47/// \param Innermost if non-NULL, the innermost template argument list.
48///
49/// \param RelativeToPrimary true if we should get the template
50/// arguments relative to the primary template, even when we're
51/// dealing with a specialization. This is only relevant for function
52/// template specializations.
53///
54/// \param Pattern If non-NULL, indicates the pattern from which we will be
55/// instantiating the definition of the given declaration, \p D. This is
56/// used to determine the proper set of template instantiation arguments for
57/// friend function template specializations.
58MultiLevelTemplateArgumentList Sema::getTemplateInstantiationArgs(
  const NamedDecl *D, const TemplateArgumentList *Innermost,
  bool RelativeToPrimary, const FunctionDecl *Pattern) {
// Accumulate the set of template argument lists in this structure.
MultiLevelTemplateArgumentList Result;

if (Innermost)
  Result.addOuterTemplateArguments(Innermost);

const auto *Ctx = dyn_cast<DeclContext>(D);
if (!Ctx) {
  Ctx = D->getDeclContext();

  // Add template arguments from a variable template instantiation. For a
  // class-scope explicit specialization, there are no template arguments
  // at this level, but there may be enclosing template arguments.
  const auto *Spec = dyn_cast<VarTemplateSpecializationDecl>(D);
  if (Spec && !Spec->isClassScopeExplicitSpecialization()) {
    // We're done when we hit an explicit specialization.
    if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
        !isa<VarTemplatePartialSpecializationDecl>(Spec))
      return Result;

    Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());

    // If this variable template specialization was instantiated from a
    // specialized member that is a variable template, we're done.
    assert(Spec->getSpecializedTemplate() && "No variable template?")(static_cast <bool> (Spec->getSpecializedTemplate() &&
 "No variable template?") ? void (0) : __assert_fail ("Spec->getSpecializedTemplate() && \"No variable template?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 85, __extension__
 __PRETTY_FUNCTION__));
    llvm::PointerUnion<VarTemplateDecl*,
                       VarTemplatePartialSpecializationDecl*> Specialized
                           = Spec->getSpecializedTemplateOrPartial();
    if (VarTemplatePartialSpecializationDecl *Partial =
            Specialized.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
      if (Partial->isMemberSpecialization())
        return Result;
    } else {
      VarTemplateDecl *Tmpl = Specialized.get<VarTemplateDecl *>();
      if (Tmpl->isMemberSpecialization())
        return Result;
    }
  }

  // If we have a template template parameter with translation unit context,
  // then we're performing substitution into a default template argument of
  // this template template parameter before we've constructed the template
  // that will own this template template parameter. In this case, we
  // use empty template parameter lists for all of the outer templates
  // to avoid performing any substitutions.
  if (Ctx->isTranslationUnit()) {
    if (const auto *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
      for (unsigned I = 0, N = TTP->getDepth() + 1; I != N; ++I)
        Result.addOuterTemplateArguments(None);
      return Result;
    }
  }
}

while (!Ctx->isFileContext()) {
  // Add template arguments from a class template instantiation.
  const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(Ctx);
  if (Spec && !Spec->isClassScopeExplicitSpecialization()) {
    // We're done when we hit an explicit specialization.
    if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
        !isa<ClassTemplatePartialSpecializationDecl>(Spec))
      break;

    Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());

    // If this class template specialization was instantiated from a
    // specialized member that is a class template, we're done.
    assert(Spec->getSpecializedTemplate() && "No class template?")(static_cast <bool> (Spec->getSpecializedTemplate() &&
 "No class template?") ? void (0) : __assert_fail ("Spec->getSpecializedTemplate() && \"No class template?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 128, __extension__
 __PRETTY_FUNCTION__));
    if (Spec->getSpecializedTemplate()->isMemberSpecialization())
      break;
  }
  // Add template arguments from a function template specialization.
  else if (const auto *Function = dyn_cast<FunctionDecl>(Ctx)) {
    if (!RelativeToPrimary &&
        Function->getTemplateSpecializationKindForInstantiation() ==
            TSK_ExplicitSpecialization)
      break;

    if (!RelativeToPrimary && Function->getTemplateSpecializationKind() ==
                                  TSK_ExplicitSpecialization) {
      // This is an implicit instantiation of an explicit specialization. We
      // don't get any template arguments from this function but might get
      // some from an enclosing template.
    } else if (const TemplateArgumentList *TemplateArgs
          = Function->getTemplateSpecializationArgs()) {
      // Add the template arguments for this specialization.
      Result.addOuterTemplateArguments(TemplateArgs);

      // If this function was instantiated from a specialized member that is
      // a function template, we're done.
      assert(Function->getPrimaryTemplate() && "No function template?")(static_cast <bool> (Function->getPrimaryTemplate() &&
 "No function template?") ? void (0) : __assert_fail ("Function->getPrimaryTemplate() && \"No function template?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 151, __extension__
 __PRETTY_FUNCTION__));
      if (Function->getPrimaryTemplate()->isMemberSpecialization())
        break;

      // If this function is a generic lambda specialization, we are done.
      if (isGenericLambdaCallOperatorOrStaticInvokerSpecialization(Function))
        break;

    } else if (Function->getDescribedFunctionTemplate()) {
      assert(Result.getNumSubstitutedLevels() == 0 &&(static_cast <bool> (Result.getNumSubstitutedLevels() ==
&& "Outer template not instantiated?") ? void (0) :
 __assert_fail ("Result.getNumSubstitutedLevels() == 0 && \"Outer template not instantiated?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 161, __extension__
 __PRETTY_FUNCTION__))
             "Outer template not instantiated?")(static_cast <bool> (Result.getNumSubstitutedLevels() ==
&& "Outer template not instantiated?") ? void (0) :
 __assert_fail ("Result.getNumSubstitutedLevels() == 0 && \"Outer template not instantiated?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 161, __extension__
 __PRETTY_FUNCTION__));
    }

    // If this is a friend declaration and it declares an entity at
    // namespace scope, take arguments from its lexical parent
    // instead of its semantic parent, unless of course the pattern we're
    // instantiating actually comes from the file's context!
    if (Function->getFriendObjectKind() &&
        Function->getDeclContext()->isFileContext() &&
        (!Pattern || !Pattern->getLexicalDeclContext()->isFileContext())) {
      Ctx = Function->getLexicalDeclContext();
      RelativeToPrimary = false;
      continue;
    }
  } else if (const auto *Rec = dyn_cast<CXXRecordDecl>(Ctx)) {
    if (ClassTemplateDecl *ClassTemplate = Rec->getDescribedClassTemplate()) {
      assert(Result.getNumSubstitutedLevels() == 0 &&(static_cast <bool> (Result.getNumSubstitutedLevels() ==
&& "Outer template not instantiated?") ? void (0) :
 __assert_fail ("Result.getNumSubstitutedLevels() == 0 && \"Outer template not instantiated?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 178, __extension__
 __PRETTY_FUNCTION__))
             "Outer template not instantiated?")(static_cast <bool> (Result.getNumSubstitutedLevels() ==
&& "Outer template not instantiated?") ? void (0) :
 __assert_fail ("Result.getNumSubstitutedLevels() == 0 && \"Outer template not instantiated?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 178, __extension__
 __PRETTY_FUNCTION__));
      if (ClassTemplate->isMemberSpecialization())
        break;
    }
  }

  Ctx = Ctx->getParent();
  RelativeToPrimary = false;
}

return Result;
189}

191bool Sema::CodeSynthesisContext::isInstantiationRecord() const {
switch (Kind) {
case TemplateInstantiation:
case ExceptionSpecInstantiation:
case DefaultTemplateArgumentInstantiation:
case DefaultFunctionArgumentInstantiation:
case ExplicitTemplateArgumentSubstitution:
case DeducedTemplateArgumentSubstitution:
case PriorTemplateArgumentSubstitution:
case ConstraintsCheck:
case NestedRequirementConstraintsCheck:
  return true;

case RequirementInstantiation:
case DefaultTemplateArgumentChecking:
case DeclaringSpecialMember:
case DeclaringImplicitEqualityComparison:
case DefiningSynthesizedFunction:
case ExceptionSpecEvaluation:
case ConstraintSubstitution:
case ParameterMappingSubstitution:
case ConstraintNormalization:
case RewritingOperatorAsSpaceship:
case InitializingStructuredBinding:
case MarkingClassDllexported:
  return false;

// This function should never be called when Kind's value is Memoization.
case Memoization:
  break;
}

llvm_unreachable("Invalid SynthesisKind!")::llvm::llvm_unreachable_internal("Invalid SynthesisKind!", "clang/lib/Sema/SemaTemplateInstantiate.cpp"
, 223);
224}

226Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, CodeSynthesisContext::SynthesisKind Kind,
  SourceLocation PointOfInstantiation, SourceRange InstantiationRange,
  Decl *Entity, NamedDecl *Template, ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo *DeductionInfo)
  : SemaRef(SemaRef) {
// Don't allow further instantiation if a fatal error and an uncompilable
// error have occurred. Any diagnostics we might have raised will not be
// visible, and we do not need to construct a correct AST.
if (SemaRef.Diags.hasFatalErrorOccurred() &&
    SemaRef.hasUncompilableErrorOccurred()) {
  Invalid = true;
  return;
}
Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
if (!Invalid) {
  CodeSynthesisContext Inst;
  Inst.Kind = Kind;
  Inst.PointOfInstantiation = PointOfInstantiation;
  Inst.Entity = Entity;
  Inst.Template = Template;
  Inst.TemplateArgs = TemplateArgs.data();
  Inst.NumTemplateArgs = TemplateArgs.size();
  Inst.DeductionInfo = DeductionInfo;
  Inst.InstantiationRange = InstantiationRange;
  SemaRef.pushCodeSynthesisContext(Inst);

  AlreadyInstantiating = !Inst.Entity ? false :
      !SemaRef.InstantiatingSpecializations
           .insert({Inst.Entity->getCanonicalDecl(), Inst.Kind})
           .second;
  atTemplateBegin(SemaRef.TemplateInstCallbacks, SemaRef, Inst);
}
259}

261Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, Decl *Entity,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(SemaRef,
                          CodeSynthesisContext::TemplateInstantiation,
                          PointOfInstantiation, InstantiationRange, Entity) {}

268Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, FunctionDecl *Entity,
  ExceptionSpecification, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ExceptionSpecInstantiation,
        PointOfInstantiation, InstantiationRange, Entity) {}

275Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateParameter Param,
  TemplateDecl *Template, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DefaultTemplateArgumentInstantiation,
        PointOfInstantiation, InstantiationRange, getAsNamedDecl(Param),
        Template, TemplateArgs) {}

285Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  FunctionTemplateDecl *FunctionTemplate,
  ArrayRef<TemplateArgument> TemplateArgs,
  CodeSynthesisContext::SynthesisKind Kind,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(SemaRef, Kind, PointOfInstantiation,
                          InstantiationRange, FunctionTemplate, nullptr,
                          TemplateArgs, &DeductionInfo) {
assert((static_cast <bool> (Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution
 || Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution
) ? void (0) : __assert_fail ("Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution || Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 296, __extension__
 __PRETTY_FUNCTION__))
  Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution ||(static_cast <bool> (Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution
 || Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution
) ? void (0) : __assert_fail ("Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution || Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 296, __extension__
 __PRETTY_FUNCTION__))
  Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution)(static_cast <bool> (Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution
 || Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution
) ? void (0) : __assert_fail ("Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution || Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 296, __extension__
 __PRETTY_FUNCTION__));
297}

299Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  TemplateDecl *Template,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        TemplateArgs, &DeductionInfo) {}

310Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ClassTemplatePartialSpecializationDecl *PartialSpec,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, PartialSpec, nullptr,
        TemplateArgs, &DeductionInfo) {}

321Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  VarTemplatePartialSpecializationDecl *PartialSpec,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, PartialSpec, nullptr,
        TemplateArgs, &DeductionInfo) {}

332Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, ParmVarDecl *Param,
  ArrayRef<TemplateArgument> TemplateArgs, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DefaultFunctionArgumentInstantiation,
        PointOfInstantiation, InstantiationRange, Param, nullptr,
        TemplateArgs) {}

341Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template,
  NonTypeTemplateParmDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::PriorTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

351Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template,
  TemplateTemplateParmDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::PriorTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

361Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateDecl *Template,
  NamedDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::DefaultTemplateArgumentChecking,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

370Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  concepts::Requirement *Req, sema::TemplateDeductionInfo &DeductionInfo,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::RequirementInstantiation,
        PointOfInstantiation, InstantiationRange, /*Entity=*/nullptr,
        /*Template=*/nullptr, /*TemplateArgs=*/None, &DeductionInfo) {}


380Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  concepts::NestedRequirement *Req, ConstraintsCheck,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::NestedRequirementConstraintsCheck,
        PointOfInstantiation, InstantiationRange, /*Entity=*/nullptr,
        /*Template=*/nullptr, /*TemplateArgs=*/None) {}


390Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintsCheck, NamedDecl *Template,
  ArrayRef<TemplateArgument> TemplateArgs, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintsCheck,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        TemplateArgs) {}

399Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintSubstitution, NamedDecl *Template,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintSubstitution,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        {}, &DeductionInfo) {}

408Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintNormalization, NamedDecl *Template,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintNormalization,
        PointOfInstantiation, InstantiationRange, Template) {}

416Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ParameterMappingSubstitution, NamedDecl *Template,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ParameterMappingSubstitution,
        PointOfInstantiation, InstantiationRange, Template) {}

424void Sema::pushCodeSynthesisContext(CodeSynthesisContext Ctx) {
Ctx.SavedInNonInstantiationSFINAEContext = InNonInstantiationSFINAEContext;
InNonInstantiationSFINAEContext = false;

CodeSynthesisContexts.push_back(Ctx);

if (!Ctx.isInstantiationRecord())
  ++NonInstantiationEntries;

// Check to see if we're low on stack space. We can't do anything about this
// from here, but we can at least warn the user.
if (isStackNearlyExhausted())
  warnStackExhausted(Ctx.PointOfInstantiation);
437}

439void Sema::popCodeSynthesisContext() {
auto &Active = CodeSynthesisContexts.back();
if (!Active.isInstantiationRecord()) {
  assert(NonInstantiationEntries > 0)(static_cast <bool> (NonInstantiationEntries > 0) ? void
 (0) : __assert_fail ("NonInstantiationEntries > 0", "clang/lib/Sema/SemaTemplateInstantiate.cpp"
, 442, __extension__ __PRETTY_FUNCTION__));
  --NonInstantiationEntries;
}

InNonInstantiationSFINAEContext = Active.SavedInNonInstantiationSFINAEContext;

// Name lookup no longer looks in this template's defining module.
assert(CodeSynthesisContexts.size() >=(static_cast <bool> (CodeSynthesisContexts.size() >=
 CodeSynthesisContextLookupModules.size() && "forgot to remove a lookup module for a template instantiation"
) ? void (0) : __assert_fail ("CodeSynthesisContexts.size() >= CodeSynthesisContextLookupModules.size() && \"forgot to remove a lookup module for a template instantiation\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 451, __extension__
 __PRETTY_FUNCTION__))
           CodeSynthesisContextLookupModules.size() &&(static_cast <bool> (CodeSynthesisContexts.size() >=
 CodeSynthesisContextLookupModules.size() && "forgot to remove a lookup module for a template instantiation"
) ? void (0) : __assert_fail ("CodeSynthesisContexts.size() >= CodeSynthesisContextLookupModules.size() && \"forgot to remove a lookup module for a template instantiation\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 451, __extension__
 __PRETTY_FUNCTION__))
       "forgot to remove a lookup module for a template instantiation")(static_cast <bool> (CodeSynthesisContexts.size() >=
 CodeSynthesisContextLookupModules.size() && "forgot to remove a lookup module for a template instantiation"
) ? void (0) : __assert_fail ("CodeSynthesisContexts.size() >= CodeSynthesisContextLookupModules.size() && \"forgot to remove a lookup module for a template instantiation\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 451, __extension__
 __PRETTY_FUNCTION__));
if (CodeSynthesisContexts.size() ==
    CodeSynthesisContextLookupModules.size()) {
  if (Module *M = CodeSynthesisContextLookupModules.back())
    LookupModulesCache.erase(M);
  CodeSynthesisContextLookupModules.pop_back();
}

// If we've left the code synthesis context for the current context stack,
// stop remembering that we've emitted that stack.
if (CodeSynthesisContexts.size() ==
    LastEmittedCodeSynthesisContextDepth)
  LastEmittedCodeSynthesisContextDepth = 0;

CodeSynthesisContexts.pop_back();
466}

468void Sema::InstantiatingTemplate::Clear() {
if (!Invalid) {
  if (!AlreadyInstantiating) {
    auto &Active = SemaRef.CodeSynthesisContexts.back();
    if (Active.Entity)
      SemaRef.InstantiatingSpecializations.erase(
          {Active.Entity->getCanonicalDecl(), Active.Kind});
  }

  atTemplateEnd(SemaRef.TemplateInstCallbacks, SemaRef,
                SemaRef.CodeSynthesisContexts.back());

  SemaRef.popCodeSynthesisContext();
  Invalid = true;
}
483}

485bool Sema::InstantiatingTemplate::CheckInstantiationDepth(
                                      SourceLocation PointOfInstantiation,
                                         SourceRange InstantiationRange) {
assert(SemaRef.NonInstantiationEntries <=(static_cast <bool> (SemaRef.NonInstantiationEntries <=
 SemaRef.CodeSynthesisContexts.size()) ? void (0) : __assert_fail
 ("SemaRef.NonInstantiationEntries <= SemaRef.CodeSynthesisContexts.size()"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 489, __extension__
 __PRETTY_FUNCTION__))
       SemaRef.CodeSynthesisContexts.size())(static_cast <bool> (SemaRef.NonInstantiationEntries <=
 SemaRef.CodeSynthesisContexts.size()) ? void (0) : __assert_fail
 ("SemaRef.NonInstantiationEntries <= SemaRef.CodeSynthesisContexts.size()"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 489, __extension__
 __PRETTY_FUNCTION__));
if ((SemaRef.CodeSynthesisContexts.size() -
        SemaRef.NonInstantiationEntries)
      <= SemaRef.getLangOpts().InstantiationDepth)
  return false;

SemaRef.Diag(PointOfInstantiation,
             diag::err_template_recursion_depth_exceeded)
  << SemaRef.getLangOpts().InstantiationDepth
  << InstantiationRange;
SemaRef.Diag(PointOfInstantiation, diag::note_template_recursion_depth)
  << SemaRef.getLangOpts().InstantiationDepth;
return true;
502}

504/// Prints the current instantiation stack through a series of
505/// notes.
506void Sema::PrintInstantiationStack() {
// Determine which template instantiations to skip, if any.
unsigned SkipStart = CodeSynthesisContexts.size(), SkipEnd = SkipStart;
unsigned Limit = Diags.getTemplateBacktraceLimit();
if (Limit && Limit < CodeSynthesisContexts.size()) {
  SkipStart = Limit / 2 + Limit % 2;
  SkipEnd = CodeSynthesisContexts.size() - Limit / 2;
}

// FIXME: In all of these cases, we need to show the template arguments
unsigned InstantiationIdx = 0;
for (SmallVectorImpl<CodeSynthesisContext>::reverse_iterator
       Active = CodeSynthesisContexts.rbegin(),
       ActiveEnd = CodeSynthesisContexts.rend();
     Active != ActiveEnd;
     ++Active, ++InstantiationIdx) {
  // Skip this instantiation?
  if (InstantiationIdx >= SkipStart && InstantiationIdx < SkipEnd) {
    if (InstantiationIdx == SkipStart) {
      // Note that we're skipping instantiations.
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_instantiation_contexts_suppressed)
        << unsigned(CodeSynthesisContexts.size() - Limit);
    }
    continue;
  }

  switch (Active->Kind) {
  case CodeSynthesisContext::TemplateInstantiation: {
    Decl *D = Active->Entity;
    if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
      unsigned DiagID = diag::note_template_member_class_here;
      if (isa<ClassTemplateSpecializationDecl>(Record))
        DiagID = diag::note_template_class_instantiation_here;
      Diags.Report(Active->PointOfInstantiation, DiagID)
        << Record << Active->InstantiationRange;
    } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
      unsigned DiagID;
      if (Function->getPrimaryTemplate())
        DiagID = diag::note_function_template_spec_here;
      else
        DiagID = diag::note_template_member_function_here;
      Diags.Report(Active->PointOfInstantiation, DiagID)
        << Function
        << Active->InstantiationRange;
    } else if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   VD->isStaticDataMember()?
                     diag::note_template_static_data_member_def_here
                   : diag::note_template_variable_def_here)
        << VD
        << Active->InstantiationRange;
    } else if (EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_enum_def_here)
        << ED
        << Active->InstantiationRange;
    } else if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_nsdmi_here)
          << FD << Active->InstantiationRange;
    } else {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_type_alias_instantiation_here)
        << cast<TypeAliasTemplateDecl>(D)
        << Active->InstantiationRange;
    }
    break;
  }

  case CodeSynthesisContext::DefaultTemplateArgumentInstantiation: {
    TemplateDecl *Template = cast<TemplateDecl>(Active->Template);
    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    Template->printName(OS);
    printTemplateArgumentList(OS, Active->template_arguments(),
                              getPrintingPolicy());
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_default_arg_instantiation_here)
      << OS.str()
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::ExplicitTemplateArgumentSubstitution: {
    FunctionTemplateDecl *FnTmpl = cast<FunctionTemplateDecl>(Active->Entity);
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_explicit_template_arg_substitution_here)
      << FnTmpl
      << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::DeducedTemplateArgumentSubstitution: {
    if (FunctionTemplateDecl *FnTmpl =
            dyn_cast<FunctionTemplateDecl>(Active->Entity)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_function_template_deduction_instantiation_here)
        << FnTmpl
        << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
                                           Active->TemplateArgs,
                                           Active->NumTemplateArgs)
        << Active->InstantiationRange;
    } else {
      bool IsVar = isa<VarTemplateDecl>(Active->Entity) ||
                   isa<VarTemplateSpecializationDecl>(Active->Entity);
      bool IsTemplate = false;
      TemplateParameterList *Params;
      if (auto *D = dyn_cast<TemplateDecl>(Active->Entity)) {
        IsTemplate = true;
        Params = D->getTemplateParameters();
      } else if (auto *D = dyn_cast<ClassTemplatePartialSpecializationDecl>(
                     Active->Entity)) {
        Params = D->getTemplateParameters();
      } else if (auto *D = dyn_cast<VarTemplatePartialSpecializationDecl>(
                     Active->Entity)) {
        Params = D->getTemplateParameters();
      } else {
        llvm_unreachable("unexpected template kind")::llvm::llvm_unreachable_internal("unexpected template kind",
 "clang/lib/Sema/SemaTemplateInstantiate.cpp", 627);
      }

      Diags.Report(Active->PointOfInstantiation,
                   diag::note_deduced_template_arg_substitution_here)
        << IsVar << IsTemplate << cast<NamedDecl>(Active->Entity)
        << getTemplateArgumentBindingsText(Params, Active->TemplateArgs,
                                           Active->NumTemplateArgs)
        << Active->InstantiationRange;
    }
    break;
  }

  case CodeSynthesisContext::DefaultFunctionArgumentInstantiation: {
    ParmVarDecl *Param = cast<ParmVarDecl>(Active->Entity);
    FunctionDecl *FD = cast<FunctionDecl>(Param->getDeclContext());

    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    FD->printName(OS);
    printTemplateArgumentList(OS, Active->template_arguments(),
                              getPrintingPolicy());
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_default_function_arg_instantiation_here)
      << OS.str()
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::PriorTemplateArgumentSubstitution: {
    NamedDecl *Parm = cast<NamedDecl>(Active->Entity);
    std::string Name;
    if (!Parm->getName().empty())
      Name = std::string(" '") + Parm->getName().str() + "'";

    TemplateParameterList *TemplateParams = nullptr;
    if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
      TemplateParams = Template->getTemplateParameters();
    else
      TemplateParams =
        cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
                                                    ->getTemplateParameters();
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_prior_template_arg_substitution)
      << isa<TemplateTemplateParmDecl>(Parm)
      << Name
      << getTemplateArgumentBindingsText(TemplateParams,
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::DefaultTemplateArgumentChecking: {
    TemplateParameterList *TemplateParams = nullptr;
    if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
      TemplateParams = Template->getTemplateParameters();
    else
      TemplateParams =
        cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
                                                    ->getTemplateParameters();

    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_default_arg_checking)
      << getTemplateArgumentBindingsText(TemplateParams,
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::ExceptionSpecEvaluation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_evaluating_exception_spec_here)
        << cast<FunctionDecl>(Active->Entity);
    break;

  case CodeSynthesisContext::ExceptionSpecInstantiation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_exception_spec_instantiation_here)
      << cast<FunctionDecl>(Active->Entity)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::RequirementInstantiation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_requirement_instantiation_here)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::NestedRequirementConstraintsCheck:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_nested_requirement_here)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::DeclaringSpecialMember:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_in_declaration_of_implicit_special_member)
      << cast<CXXRecordDecl>(Active->Entity) << Active->SpecialMember;
    break;

  case CodeSynthesisContext::DeclaringImplicitEqualityComparison:
    Diags.Report(Active->Entity->getLocation(),
                 diag::note_in_declaration_of_implicit_equality_comparison);
    break;

  case CodeSynthesisContext::DefiningSynthesizedFunction: {
    // FIXME: For synthesized functions that are not defaulted,
    // produce a note.
    auto *FD = dyn_cast<FunctionDecl>(Active->Entity);
    DefaultedFunctionKind DFK =
        FD ? getDefaultedFunctionKind(FD) : DefaultedFunctionKind();
    if (DFK.isSpecialMember()) {
      auto *MD = cast<CXXMethodDecl>(FD);
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_member_synthesized_at)
          << MD->isExplicitlyDefaulted() << DFK.asSpecialMember()
          << Context.getTagDeclType(MD->getParent());
    } else if (DFK.isComparison()) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_comparison_synthesized_at)
          << (int)DFK.asComparison()
          << Context.getTagDeclType(
                 cast<CXXRecordDecl>(FD->getLexicalDeclContext()));
    }
    break;
  }

  case CodeSynthesisContext::RewritingOperatorAsSpaceship:
    Diags.Report(Active->Entity->getLocation(),
                 diag::note_rewriting_operator_as_spaceship);
    break;

  case CodeSynthesisContext::InitializingStructuredBinding:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_in_binding_decl_init)
        << cast<BindingDecl>(Active->Entity);
    break;

  case CodeSynthesisContext::MarkingClassDllexported:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_due_to_dllexported_class)
        << cast<CXXRecordDecl>(Active->Entity) << !getLangOpts().CPlusPlus11;
    break;

  case CodeSynthesisContext::Memoization:
    break;

  case CodeSynthesisContext::ConstraintsCheck: {
    unsigned DiagID = 0;
    if (!Active->Entity) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_nested_requirement_here)
        << Active->InstantiationRange;
      break;
    }
    if (isa<ConceptDecl>(Active->Entity))
      DiagID = diag::note_concept_specialization_here;
    else if (isa<TemplateDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_template_id_here;
    else if (isa<VarTemplatePartialSpecializationDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_var_spec_id_here;
    else if (isa<ClassTemplatePartialSpecializationDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_class_spec_id_here;
    else {
      assert(isa<FunctionDecl>(Active->Entity))(static_cast <bool> (isa<FunctionDecl>(Active->
Entity)) ? void (0) : __assert_fail ("isa<FunctionDecl>(Active->Entity)"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 793, __extension__
 __PRETTY_FUNCTION__));
      DiagID = diag::note_checking_constraints_for_function_here;
    }
    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    cast<NamedDecl>(Active->Entity)->printName(OS);
    if (!isa<FunctionDecl>(Active->Entity)) {
      printTemplateArgumentList(OS, Active->template_arguments(),
                                getPrintingPolicy());
    }
    Diags.Report(Active->PointOfInstantiation, DiagID) << OS.str()
      << Active->InstantiationRange;
    break;
  }
  case CodeSynthesisContext::ConstraintSubstitution:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_constraint_substitution_here)
        << Active->InstantiationRange;
    break;
  case CodeSynthesisContext::ConstraintNormalization:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_constraint_normalization_here)
        << cast<NamedDecl>(Active->Entity)->getName()
        << Active->InstantiationRange;
    break;
  case CodeSynthesisContext::ParameterMappingSubstitution:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_parameter_mapping_substitution_here)
        << Active->InstantiationRange;
    break;
  }
}
825}

827Optional<TemplateDeductionInfo *> Sema::isSFINAEContext() const {
if (InNonInstantiationSFINAEContext)
  return Optional<TemplateDeductionInfo *>(nullptr);

for (SmallVectorImpl<CodeSynthesisContext>::const_reverse_iterator
       Active = CodeSynthesisContexts.rbegin(),
       ActiveEnd = CodeSynthesisContexts.rend();
     Active != ActiveEnd;
     ++Active)
{
  switch (Active->Kind) {
  case CodeSynthesisContext::TemplateInstantiation:
    // An instantiation of an alias template may or may not be a SFINAE
    // context, depending on what else is on the stack.
    if (isa<TypeAliasTemplateDecl>(Active->Entity))
      break;
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case CodeSynthesisContext::DefaultFunctionArgumentInstantiation:
  case CodeSynthesisContext::ExceptionSpecInstantiation:
  case CodeSynthesisContext::ConstraintsCheck:
  case CodeSynthesisContext::ParameterMappingSubstitution:
  case CodeSynthesisContext::ConstraintNormalization:
  case CodeSynthesisContext::NestedRequirementConstraintsCheck:
    // This is a template instantiation, so there is no SFINAE.
    return None;

  case CodeSynthesisContext::DefaultTemplateArgumentInstantiation:
  case CodeSynthesisContext::PriorTemplateArgumentSubstitution:
  case CodeSynthesisContext::DefaultTemplateArgumentChecking:
  case CodeSynthesisContext::RewritingOperatorAsSpaceship:
    // A default template argument instantiation and substitution into
    // template parameters with arguments for prior parameters may or may
    // not be a SFINAE context; look further up the stack.
    break;

  case CodeSynthesisContext::ExplicitTemplateArgumentSubstitution:
  case CodeSynthesisContext::DeducedTemplateArgumentSubstitution:
  case CodeSynthesisContext::ConstraintSubstitution:
  case CodeSynthesisContext::RequirementInstantiation:
    // We're either substituting explicitly-specified template arguments,
    // deduced template arguments, a constraint expression or a requirement
    // in a requires expression, so SFINAE applies.
    assert(Active->DeductionInfo && "Missing deduction info pointer")(static_cast <bool> (Active->DeductionInfo &&
 "Missing deduction info pointer") ? void (0) : __assert_fail
 ("Active->DeductionInfo && \"Missing deduction info pointer\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 869, __extension__
 __PRETTY_FUNCTION__));
    return Active->DeductionInfo;

  case CodeSynthesisContext::DeclaringSpecialMember:
  case CodeSynthesisContext::DeclaringImplicitEqualityComparison:
  case CodeSynthesisContext::DefiningSynthesizedFunction:
  case CodeSynthesisContext::InitializingStructuredBinding:
  case CodeSynthesisContext::MarkingClassDllexported:
    // This happens in a context unrelated to template instantiation, so
    // there is no SFINAE.
    return None;

  case CodeSynthesisContext::ExceptionSpecEvaluation:
    // FIXME: This should not be treated as a SFINAE context, because
    // we will cache an incorrect exception specification. However, clang
    // bootstrap relies this! See PR31692.
    break;

  case CodeSynthesisContext::Memoization:
    break;
  }

  // The inner context was transparent for SFINAE. If it occurred within a
  // non-instantiation SFINAE context, then SFINAE applies.
  if (Active->SavedInNonInstantiationSFINAEContext)
    return Optional<TemplateDeductionInfo *>(nullptr);
}

return None;
898}

900//===----------------------------------------------------------------------===/
901// Template Instantiation for Types
902//===----------------------------------------------------------------------===/
903namespace {
class TemplateInstantiator : public TreeTransform<TemplateInstantiator> {
  const MultiLevelTemplateArgumentList &TemplateArgs;
  SourceLocation Loc;
  DeclarationName Entity;

public:
  typedef TreeTransform<TemplateInstantiator> inherited;

  TemplateInstantiator(Sema &SemaRef,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       SourceLocation Loc,
                       DeclarationName Entity)
    : inherited(SemaRef), TemplateArgs(TemplateArgs), Loc(Loc),
      Entity(Entity) { }

  /// Determine whether the given type \p T has already been
  /// transformed.
  ///
  /// For the purposes of template instantiation, a type has already been
  /// transformed if it is NULL or if it is not dependent.
  bool AlreadyTransformed(QualType T);

  /// Returns the location of the entity being instantiated, if known.
  SourceLocation getBaseLocation() { return Loc; }

  /// Returns the name of the entity being instantiated, if any.
  DeclarationName getBaseEntity() { return Entity; }

  /// Sets the "base" location and entity when that
  /// information is known based on another transformation.
  void setBase(SourceLocation Loc, DeclarationName Entity) {
    this->Loc = Loc;
    this->Entity = Entity;
  }

  unsigned TransformTemplateDepth(unsigned Depth) {
    return TemplateArgs.getNewDepth(Depth);
  }

  bool TryExpandParameterPacks(SourceLocation EllipsisLoc,
                               SourceRange PatternRange,
                               ArrayRef<UnexpandedParameterPack> Unexpanded,
                               bool &ShouldExpand, bool &RetainExpansion,
                               Optional<unsigned> &NumExpansions) {
    return getSema().CheckParameterPacksForExpansion(EllipsisLoc,
                                                     PatternRange, Unexpanded,
                                                     TemplateArgs,
                                                     ShouldExpand,
                                                     RetainExpansion,
                                                     NumExpansions);
  }

  void ExpandingFunctionParameterPack(ParmVarDecl *Pack) {
    SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Pack);
  }

  TemplateArgument ForgetPartiallySubstitutedPack() {
    TemplateArgument Result;
    if (NamedDecl *PartialPack
          = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
      MultiLevelTemplateArgumentList &TemplateArgs
        = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
      unsigned Depth, Index;
      std::tie(Depth, Index) = getDepthAndIndex(PartialPack);
      if (TemplateArgs.hasTemplateArgument(Depth, Index)) {
        Result = TemplateArgs(Depth, Index);
        TemplateArgs.setArgument(Depth, Index, TemplateArgument());
      }
    }

    return Result;
  }

  void RememberPartiallySubstitutedPack(TemplateArgument Arg) {
    if (Arg.isNull())
      return;

    if (NamedDecl *PartialPack
          = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
      MultiLevelTemplateArgumentList &TemplateArgs
      = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
      unsigned Depth, Index;
      std::tie(Depth, Index) = getDepthAndIndex(PartialPack);
      TemplateArgs.setArgument(Depth, Index, Arg);
    }
  }

  /// Transform the given declaration by instantiating a reference to
  /// this declaration.
  Decl *TransformDecl(SourceLocation Loc, Decl *D);

  void transformAttrs(Decl *Old, Decl *New) {
    SemaRef.InstantiateAttrs(TemplateArgs, Old, New);
  }

  void transformedLocalDecl(Decl *Old, ArrayRef<Decl *> NewDecls) {
    if (Old->isParameterPack()) {
1
Assuming the condition is false→
      SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Old);
      for (auto *New : NewDecls)
        SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(
            Old, cast<VarDecl>(New));
      return;
    }

    assert(NewDecls.size() == 1 &&(static_cast <bool> (NewDecls.size() == 1 && "should only have multiple expansions for a pack"
) ? void (0) : __assert_fail ("NewDecls.size() == 1 && \"should only have multiple expansions for a pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1009, __extension__
 __PRETTY_FUNCTION__))
2
←
Taking false branch→
3
←
Assuming the condition is true→
4
←
'?' condition is true→
           "should only have multiple expansions for a pack")(static_cast <bool> (NewDecls.size() == 1 && "should only have multiple expansions for a pack"
) ? void (0) : __assert_fail ("NewDecls.size() == 1 && \"should only have multiple expansions for a pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1009, __extension__
 __PRETTY_FUNCTION__));
    Decl *New = NewDecls.front();

    // If we've instantiated the call operator of a lambda or the call
    // operator template of a generic lambda, update the "instantiation of"
    // information.
    auto *NewMD = dyn_cast<CXXMethodDecl>(New);
5
←
Assuming 'New' is a 'CXXMethodDecl'→
    if (NewMD5.1
'NewMD' is non-null
 && isLambdaCallOperator(NewMD)) {
6
←
Taking true branch→
      auto *OldMD = dyn_cast<CXXMethodDecl>(Old);
7
←
Assuming 'Old' is not a 'CXXMethodDecl'→
8
←
'OldMD' initialized to a null pointer value→
      if (auto *NewTD = NewMD->getDescribedFunctionTemplate())
9
←
Assuming 'NewTD' is non-null→
10
←
Taking true branch→
        NewTD->setInstantiatedFromMemberTemplate(
            OldMD->getDescribedFunctionTemplate());
11
←
Called C++ object pointer is null
      else
        NewMD->setInstantiationOfMemberFunction(OldMD,
                                                TSK_ImplicitInstantiation);
    }

    SemaRef.CurrentInstantiationScope->InstantiatedLocal(Old, New);

    // We recreated a local declaration, but not by instantiating it. There
    // may be pending dependent diagnostics to produce.
    if (auto *DC = dyn_cast<DeclContext>(Old))
      SemaRef.PerformDependentDiagnostics(DC, TemplateArgs);
  }

  /// Transform the definition of the given declaration by
  /// instantiating it.
  Decl *TransformDefinition(SourceLocation Loc, Decl *D);

  /// Transform the first qualifier within a scope by instantiating the
  /// declaration.
  NamedDecl *TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc);

  /// Rebuild the exception declaration and register the declaration
  /// as an instantiated local.
  VarDecl *RebuildExceptionDecl(VarDecl *ExceptionDecl,
                                TypeSourceInfo *Declarator,
                                SourceLocation StartLoc,
                                SourceLocation NameLoc,
                                IdentifierInfo *Name);

  /// Rebuild the Objective-C exception declaration and register the
  /// declaration as an instantiated local.
  VarDecl *RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
                                    TypeSourceInfo *TSInfo, QualType T);

  /// Check for tag mismatches when instantiating an
  /// elaborated type.
  QualType RebuildElaboratedType(SourceLocation KeywordLoc,
                                 ElaboratedTypeKeyword Keyword,
                                 NestedNameSpecifierLoc QualifierLoc,
                                 QualType T);

  TemplateName
  TransformTemplateName(CXXScopeSpec &SS, TemplateName Name,
                        SourceLocation NameLoc,
                        QualType ObjectType = QualType(),
                        NamedDecl *FirstQualifierInScope = nullptr,
                        bool AllowInjectedClassName = false);

  const LoopHintAttr *TransformLoopHintAttr(const LoopHintAttr *LH);

  ExprResult TransformPredefinedExpr(PredefinedExpr *E);
  ExprResult TransformDeclRefExpr(DeclRefExpr *E);
  ExprResult TransformCXXDefaultArgExpr(CXXDefaultArgExpr *E);

  ExprResult TransformTemplateParmRefExpr(DeclRefExpr *E,
                                          NonTypeTemplateParmDecl *D);
  ExprResult TransformSubstNonTypeTemplateParmPackExpr(
                                         SubstNonTypeTemplateParmPackExpr *E);
  ExprResult TransformSubstNonTypeTemplateParmExpr(
                                         SubstNonTypeTemplateParmExpr *E);

  /// Rebuild a DeclRefExpr for a VarDecl reference.
  ExprResult RebuildVarDeclRefExpr(VarDecl *PD, SourceLocation Loc);

  /// Transform a reference to a function or init-capture parameter pack.
  ExprResult TransformFunctionParmPackRefExpr(DeclRefExpr *E, VarDecl *PD);

  /// Transform a FunctionParmPackExpr which was built when we couldn't
  /// expand a function parameter pack reference which refers to an expanded
  /// pack.
  ExprResult TransformFunctionParmPackExpr(FunctionParmPackExpr *E);

  QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
                                      FunctionProtoTypeLoc TL) {
    // Call the base version; it will forward to our overridden version below.
    return inherited::TransformFunctionProtoType(TLB, TL);
  }

  template<typename Fn>
  QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
                                      FunctionProtoTypeLoc TL,
                                      CXXRecordDecl *ThisContext,
                                      Qualifiers ThisTypeQuals,
                                      Fn TransformExceptionSpec);

  ParmVarDecl *TransformFunctionTypeParam(ParmVarDecl *OldParm,
                                          int indexAdjustment,
                                          Optional<unsigned> NumExpansions,
                                          bool ExpectParameterPack);

  /// Transforms a template type parameter type by performing
  /// substitution of the corresponding template type argument.
  QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
                                         TemplateTypeParmTypeLoc TL);

  /// Transforms an already-substituted template type parameter pack
  /// into either itself (if we aren't substituting into its pack expansion)
  /// or the appropriate substituted argument.
  QualType TransformSubstTemplateTypeParmPackType(TypeLocBuilder &TLB,
                                         SubstTemplateTypeParmPackTypeLoc TL);

  ExprResult TransformLambdaExpr(LambdaExpr *E) {
    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
    return inherited::TransformLambdaExpr(E);
  }

  ExprResult TransformRequiresExpr(RequiresExpr *E) {
    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
    return inherited::TransformRequiresExpr(E);
  }

  bool TransformRequiresExprRequirements(
      ArrayRef<concepts::Requirement *> Reqs,
      SmallVectorImpl<concepts::Requirement *> &Transformed) {
    bool SatisfactionDetermined = false;
    for (concepts::Requirement *Req : Reqs) {
      concepts::Requirement *TransReq = nullptr;
      if (!SatisfactionDetermined) {
        if (auto *TypeReq = dyn_cast<concepts::TypeRequirement>(Req))
          TransReq = TransformTypeRequirement(TypeReq);
        else if (auto *ExprReq = dyn_cast<concepts::ExprRequirement>(Req))
          TransReq = TransformExprRequirement(ExprReq);
        else
          TransReq = TransformNestedRequirement(
              cast<concepts::NestedRequirement>(Req));
        if (!TransReq)
          return true;
        if (!TransReq->isDependent() && !TransReq->isSatisfied())
          // [expr.prim.req]p6
          //   [...]  The substitution and semantic constraint checking
          //   proceeds in lexical order and stops when a condition that
          //   determines the result of the requires-expression is
          //   encountered. [..]
          SatisfactionDetermined = true;
      } else
        TransReq = Req;
      Transformed.push_back(TransReq);
    }
    return false;
  }

  TemplateParameterList *TransformTemplateParameterList(
                            TemplateParameterList *OrigTPL)  {
    if (!OrigTPL || !OrigTPL->size()) return OrigTPL;

    DeclContext *Owner = OrigTPL->getParam(0)->getDeclContext();
    TemplateDeclInstantiator  DeclInstantiator(getSema(),
                      /* DeclContext *Owner */ Owner, TemplateArgs);
    return DeclInstantiator.SubstTemplateParams(OrigTPL);
  }

  concepts::TypeRequirement *
  TransformTypeRequirement(concepts::TypeRequirement *Req);
  concepts::ExprRequirement *
  TransformExprRequirement(concepts::ExprRequirement *Req);
  concepts::NestedRequirement *
  TransformNestedRequirement(concepts::NestedRequirement *Req);

private:
  ExprResult transformNonTypeTemplateParmRef(NonTypeTemplateParmDecl *parm,
                                             SourceLocation loc,
                                             TemplateArgument arg);
};
1184}

1186bool TemplateInstantiator::AlreadyTransformed(QualType T) {
if (T.isNull())
  return true;

if (T->isInstantiationDependentType() || T->isVariablyModifiedType())
  return false;

getSema().MarkDeclarationsReferencedInType(Loc, T);
return true;
1195}

1197static TemplateArgument
1198getPackSubstitutedTemplateArgument(Sema &S, TemplateArgument Arg) {
assert(S.ArgumentPackSubstitutionIndex >= 0)(static_cast <bool> (S.ArgumentPackSubstitutionIndex >=
 0) ? void (0) : __assert_fail ("S.ArgumentPackSubstitutionIndex >= 0"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1199, __extension__
 __PRETTY_FUNCTION__));
assert(S.ArgumentPackSubstitutionIndex < (int)Arg.pack_size())(static_cast <bool> (S.ArgumentPackSubstitutionIndex <
 (int)Arg.pack_size()) ? void (0) : __assert_fail ("S.ArgumentPackSubstitutionIndex < (int)Arg.pack_size()"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1200, __extension__
 __PRETTY_FUNCTION__));
Arg = Arg.pack_begin()[S.ArgumentPackSubstitutionIndex];
if (Arg.isPackExpansion())
  Arg = Arg.getPackExpansionPattern();
return Arg;
1205}

1207Decl *TemplateInstantiator::TransformDecl(SourceLocation Loc, Decl *D) {
if (!D)
  return nullptr;

if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // If the corresponding template argument is NULL or non-existent, it's
    // because we are performing instantiation from explicitly-specified
    // template arguments in a function template, but there were some
    // arguments left unspecified.
    if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
                                          TTP->getPosition()))
      return D;

    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1225, __extension__
 __PRETTY_FUNCTION__))
             "Missing argument pack")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1225, __extension__
 __PRETTY_FUNCTION__));
      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    TemplateName Template = Arg.getAsTemplate().getNameToSubstitute();
    assert(!Template.isNull() && Template.getAsTemplateDecl() &&(static_cast <bool> (!Template.isNull() && Template
.getAsTemplateDecl() && "Wrong kind of template template argument"
) ? void (0) : __assert_fail ("!Template.isNull() && Template.getAsTemplateDecl() && \"Wrong kind of template template argument\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1231, __extension__
 __PRETTY_FUNCTION__))
           "Wrong kind of template template argument")(static_cast <bool> (!Template.isNull() && Template
.getAsTemplateDecl() && "Wrong kind of template template argument"
) ? void (0) : __assert_fail ("!Template.isNull() && Template.getAsTemplateDecl() && \"Wrong kind of template template argument\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1231, __extension__
 __PRETTY_FUNCTION__));
    return Template.getAsTemplateDecl();
  }

  // Fall through to find the instantiated declaration for this template
  // template parameter.
}

return SemaRef.FindInstantiatedDecl(Loc, cast<NamedDecl>(D), TemplateArgs);
1240}

1242Decl *TemplateInstantiator::TransformDefinition(SourceLocation Loc, Decl *D) {
Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs);
if (!Inst)
  return nullptr;

getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst);
return Inst;
1249}

1251NamedDecl *
1252TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D,
                                                   SourceLocation Loc) {
// If the first part of the nested-name-specifier was a template type
// parameter, instantiate that type parameter down to a tag type.
if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null<TemplateTypeParmDecl>(D)) {
  const TemplateTypeParmType *TTP
    = cast<TemplateTypeParmType>(getSema().Context.getTypeDeclType(TTPD));

  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // FIXME: This needs testing w/ member access expressions.
    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getIndex());

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1266, __extension__
 __PRETTY_FUNCTION__))
             "Missing argument pack")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1266, __extension__
 __PRETTY_FUNCTION__));

      if (getSema().ArgumentPackSubstitutionIndex == -1)
        return nullptr;

      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    QualType T = Arg.getAsType();
    if (T.isNull())
      return cast_or_null<NamedDecl>(TransformDecl(Loc, D));

    if (const TagType *Tag = T->getAs<TagType>())
      return Tag->getDecl();

    // The resulting type is not a tag; complain.
    getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T;
    return nullptr;
  }
}

return cast_or_null<NamedDecl>(TransformDecl(Loc, D));
1288}

1290VarDecl *
1291TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl,
                                         TypeSourceInfo *Declarator,
                                         SourceLocation StartLoc,
                                         SourceLocation NameLoc,
                                         IdentifierInfo *Name) {
VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, Declarator,
                                               StartLoc, NameLoc, Name);
if (Var)
  getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
return Var;
1301}

1303VarDecl *TemplateInstantiator::RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
                                                      TypeSourceInfo *TSInfo,
                                                      QualType T) {
VarDecl *Var = inherited::RebuildObjCExceptionDecl(ExceptionDecl, TSInfo, T);
if (Var)
  getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
return Var;
1310}

1312QualType
1313TemplateInstantiator::RebuildElaboratedType(SourceLocation KeywordLoc,
                                          ElaboratedTypeKeyword Keyword,
                                          NestedNameSpecifierLoc QualifierLoc,
                                          QualType T) {
if (const TagType *TT = T->getAs<TagType>()) {
  TagDecl* TD = TT->getDecl();

  SourceLocation TagLocation = KeywordLoc;

  IdentifierInfo *Id = TD->getIdentifier();

  // TODO: should we even warn on struct/class mismatches for this?  Seems
  // like it's likely to produce a lot of spurious errors.
  if (Id && Keyword != ETK_None && Keyword != ETK_Typename) {
    TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForKeyword(Keyword);
    if (!SemaRef.isAcceptableTagRedeclaration(TD, Kind, /*isDefinition*/false,
                                              TagLocation, Id)) {
      SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
        << Id
        << FixItHint::CreateReplacement(SourceRange(TagLocation),
                                        TD->getKindName());
      SemaRef.Diag(TD->getLocation(), diag::note_previous_use);
    }
  }
}

return inherited::RebuildElaboratedType(KeywordLoc, Keyword, QualifierLoc, T);
1340}

1342TemplateName TemplateInstantiator::TransformTemplateName(
  CXXScopeSpec &SS, TemplateName Name, SourceLocation NameLoc,
  QualType ObjectType, NamedDecl *FirstQualifierInScope,
  bool AllowInjectedClassName) {
if (TemplateTemplateParmDecl *TTP
     = dyn_cast_or_null<TemplateTemplateParmDecl>(Name.getAsTemplateDecl())) {
  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // If the corresponding template argument is NULL or non-existent, it's
    // because we are performing instantiation from explicitly-specified
    // template arguments in a function template, but there were some
    // arguments left unspecified.
    if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
                                          TTP->getPosition()))
      return Name;

    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());

    if (TemplateArgs.isRewrite()) {
      // We're rewriting the template parameter as a reference to another
      // template parameter.
      if (Arg.getKind() == TemplateArgument::Pack) {
        assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&(static_cast <bool> (Arg.pack_size() == 1 && Arg
.pack_begin()->isPackExpansion() && "unexpected pack arguments in template rewrite"
) ? void (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() && \"unexpected pack arguments in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1364, __extension__
 __PRETTY_FUNCTION__))
               "unexpected pack arguments in template rewrite")(static_cast <bool> (Arg.pack_size() == 1 && Arg
.pack_begin()->isPackExpansion() && "unexpected pack arguments in template rewrite"
) ? void (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() && \"unexpected pack arguments in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1364, __extension__
 __PRETTY_FUNCTION__));
        Arg = Arg.pack_begin()->getPackExpansionPattern();
      }
      assert(Arg.getKind() == TemplateArgument::Template &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Template && "unexpected nontype template argument kind in template rewrite"
) ? void (0) : __assert_fail ("Arg.getKind() == TemplateArgument::Template && \"unexpected nontype template argument kind in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1368, __extension__
 __PRETTY_FUNCTION__))
             "unexpected nontype template argument kind in template rewrite")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Template && "unexpected nontype template argument kind in template rewrite"
) ? void (0) : __assert_fail ("Arg.getKind() == TemplateArgument::Template && \"unexpected nontype template argument kind in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1368, __extension__
 __PRETTY_FUNCTION__));
      return Arg.getAsTemplate();
    }

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1374, __extension__
 __PRETTY_FUNCTION__))
             "Missing argument pack")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1374, __extension__
 __PRETTY_FUNCTION__));

      if (getSema().ArgumentPackSubstitutionIndex == -1) {
        // We have the template argument pack to substitute, but we're not
        // actually expanding the enclosing pack expansion yet. So, just
        // keep the entire argument pack.
        return getSema().Context.getSubstTemplateTemplateParmPack(TTP, Arg);
      }

      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    TemplateName Template = Arg.getAsTemplate().getNameToSubstitute();
    assert(!Template.isNull() && "Null template template argument")(static_cast <bool> (!Template.isNull() && "Null template template argument"
) ? void (0) : __assert_fail ("!Template.isNull() && \"Null template template argument\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1387, __extension__
 __PRETTY_FUNCTION__));
    assert(!Template.getAsQualifiedTemplateName() &&(static_cast <bool> (!Template.getAsQualifiedTemplateName
() && "template decl to substitute is qualified?") ? void
 (0) : __assert_fail ("!Template.getAsQualifiedTemplateName() && \"template decl to substitute is qualified?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1389, __extension__
 __PRETTY_FUNCTION__))
           "template decl to substitute is qualified?")(static_cast <bool> (!Template.getAsQualifiedTemplateName
() && "template decl to substitute is qualified?") ? void
 (0) : __assert_fail ("!Template.getAsQualifiedTemplateName() && \"template decl to substitute is qualified?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1389, __extension__
 __PRETTY_FUNCTION__));

    Template = getSema().Context.getSubstTemplateTemplateParm(TTP, Template);
    return Template;
  }
}

if (SubstTemplateTemplateParmPackStorage *SubstPack
    = Name.getAsSubstTemplateTemplateParmPack()) {
  if (getSema().ArgumentPackSubstitutionIndex == -1)
    return Name;

  TemplateArgument Arg = SubstPack->getArgumentPack();
  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
  return Arg.getAsTemplate().getNameToSubstitute();
}

return inherited::TransformTemplateName(SS, Name, NameLoc, ObjectType,
                                        FirstQualifierInScope,
                                        AllowInjectedClassName);
1409}

1411ExprResult
1412TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) {
if (!E->isTypeDependent())
  return E;

return getSema().BuildPredefinedExpr(E->getLocation(), E->getIdentKind());
1417}

1419ExprResult
1420TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
                                             NonTypeTemplateParmDecl *NTTP) {
// If the corresponding template argument is NULL or non-existent, it's
// because we are performing instantiation from explicitly-specified
// template arguments in a function template, but there were some
// arguments left unspecified.
if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(),
                                      NTTP->getPosition()))
  return E;

TemplateArgument Arg = TemplateArgs(NTTP->getDepth(), NTTP->getPosition());

if (TemplateArgs.isRewrite()) {
  // We're rewriting the template parameter as a reference to another
  // template parameter.
  if (Arg.getKind() == TemplateArgument::Pack) {
    assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&(static_cast <bool> (Arg.pack_size() == 1 && Arg
.pack_begin()->isPackExpansion() && "unexpected pack arguments in template rewrite"
) ? void (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() && \"unexpected pack arguments in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1437, __extension__
 __PRETTY_FUNCTION__))
           "unexpected pack arguments in template rewrite")(static_cast <bool> (Arg.pack_size() == 1 && Arg
.pack_begin()->isPackExpansion() && "unexpected pack arguments in template rewrite"
) ? void (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() && \"unexpected pack arguments in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1437, __extension__
 __PRETTY_FUNCTION__));
    Arg = Arg.pack_begin()->getPackExpansionPattern();
  }
  assert(Arg.getKind() == TemplateArgument::Expression &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Expression && "unexpected nontype template argument kind in template rewrite"
) ? void (0) : __assert_fail ("Arg.getKind() == TemplateArgument::Expression && \"unexpected nontype template argument kind in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1441, __extension__
 __PRETTY_FUNCTION__))
         "unexpected nontype template argument kind in template rewrite")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Expression && "unexpected nontype template argument kind in template rewrite"
) ? void (0) : __assert_fail ("Arg.getKind() == TemplateArgument::Expression && \"unexpected nontype template argument kind in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1441, __extension__
 __PRETTY_FUNCTION__));
  // FIXME: This can lead to the same subexpression appearing multiple times
  // in a complete expression.
  return Arg.getAsExpr();
}

if (NTTP->isParameterPack()) {
  assert(Arg.getKind() == TemplateArgument::Pack &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1449, __extension__
 __PRETTY_FUNCTION__))
         "Missing argument pack")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1449, __extension__
 __PRETTY_FUNCTION__));

  if (getSema().ArgumentPackSubstitutionIndex == -1) {
    // We have an argument pack, but we can't select a particular argument
    // out of it yet. Therefore, we'll build an expression to hold on to that
    // argument pack.
    QualType TargetType = SemaRef.SubstType(NTTP->getType(), TemplateArgs,
                                            E->getLocation(),
                                            NTTP->getDeclName());
    if (TargetType.isNull())
      return ExprError();

    QualType ExprType = TargetType.getNonLValueExprType(SemaRef.Context);
    if (TargetType->isRecordType())
      ExprType.addConst();

    return new (SemaRef.Context) SubstNonTypeTemplateParmPackExpr(
        ExprType, TargetType->isReferenceType() ? VK_LValue : VK_PRValue,
        NTTP, E->getLocation(), Arg);
  }

  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
}

return transformNonTypeTemplateParmRef(NTTP, E->getLocation(), Arg);
1474}

1476const LoopHintAttr *
1477TemplateInstantiator::TransformLoopHintAttr(const LoopHintAttr *LH) {
Expr *TransformedExpr = getDerived().TransformExpr(LH->getValue()).get();

if (TransformedExpr == LH->getValue())
  return LH;

// Generate error if there is a problem with the value.
if (getSema().CheckLoopHintExpr(TransformedExpr, LH->getLocation()))
  return LH;

// Create new LoopHintValueAttr with integral expression in place of the
// non-type template parameter.
return LoopHintAttr::CreateImplicit(getSema().Context, LH->getOption(),
                                    LH->getState(), TransformedExpr, *LH);
1491}

1493ExprResult TemplateInstantiator::transformNonTypeTemplateParmRef(
                                               NonTypeTemplateParmDecl *parm,
                                               SourceLocation loc,
                                               TemplateArgument arg) {
ExprResult result;

// Determine the substituted parameter type. We can usually infer this from
// the template argument, but not always.
auto SubstParamType = [&] {
  QualType T;
  if (parm->isExpandedParameterPack())
    T = parm->getExpansionType(SemaRef.ArgumentPackSubstitutionIndex);
  else
    T = parm->getType();
  if (parm->isParameterPack() && isa<PackExpansionType>(T))
    T = cast<PackExpansionType>(T)->getPattern();
  return SemaRef.SubstType(T, TemplateArgs, loc, parm->getDeclName());
};

bool refParam = false;

// The template argument itself might be an expression, in which case we just
// return that expression. This happens when substituting into an alias
// template.
if (arg.getKind() == TemplateArgument::Expression) {
  Expr *argExpr = arg.getAsExpr();
  result = argExpr;
  if (argExpr->isLValue()) {
    if (argExpr->getType()->isRecordType()) {
      // Check whether the parameter was actually a reference.
      QualType paramType = SubstParamType();
      if (paramType.isNull())
        return ExprError();
      refParam = paramType->isReferenceType();
    } else {
      refParam = true;
    }
  }
} else if (arg.getKind() == TemplateArgument::Declaration ||
           arg.getKind() == TemplateArgument::NullPtr) {
  ValueDecl *VD;
  if (arg.getKind() == TemplateArgument::Declaration) {
    VD = arg.getAsDecl();

    // Find the instantiation of the template argument.  This is
    // required for nested templates.
    VD = cast_or_null<ValueDecl>(
           getSema().FindInstantiatedDecl(loc, VD, TemplateArgs));
    if (!VD)
      return ExprError();
  } else {
    // Propagate NULL template argument.
    VD = nullptr;
  }

  QualType paramType = VD ? arg.getParamTypeForDecl() : arg.getNullPtrType();
  assert(!paramType.isNull() && "type substitution failed for param type")(static_cast <bool> (!paramType.isNull() && "type substitution failed for param type"
) ? void (0) : __assert_fail ("!paramType.isNull() && \"type substitution failed for param type\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1549, __extension__
 __PRETTY_FUNCTION__));
  assert(!paramType->isDependentType() && "param type still dependent")(static_cast <bool> (!paramType->isDependentType() &&
 "param type still dependent") ? void (0) : __assert_fail ("!paramType->isDependentType() && \"param type still dependent\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1550, __extension__
 __PRETTY_FUNCTION__));
  result = SemaRef.BuildExpressionFromDeclTemplateArgument(arg, paramType, loc);
  refParam = paramType->isReferenceType();
} else {
  result = SemaRef.BuildExpressionFromIntegralTemplateArgument(arg, loc);
  assert(result.isInvalid() ||(static_cast <bool> (result.isInvalid() || SemaRef.Context
.hasSameType(result.get()->getType(), arg.getIntegralType(
))) ? void (0) : __assert_fail ("result.isInvalid() || SemaRef.Context.hasSameType(result.get()->getType(), arg.getIntegralType())"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1557, __extension__
 __PRETTY_FUNCTION__))
         SemaRef.Context.hasSameType(result.get()->getType(),(static_cast <bool> (result.isInvalid() || SemaRef.Context
.hasSameType(result.get()->getType(), arg.getIntegralType(
))) ? void (0) : __assert_fail ("result.isInvalid() || SemaRef.Context.hasSameType(result.get()->getType(), arg.getIntegralType())"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1557, __extension__
 __PRETTY_FUNCTION__))
                                     arg.getIntegralType()))(static_cast <bool> (result.isInvalid() || SemaRef.Context
.hasSameType(result.get()->getType(), arg.getIntegralType(
))) ? void (0) : __assert_fail ("result.isInvalid() || SemaRef.Context.hasSameType(result.get()->getType(), arg.getIntegralType())"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1557, __extension__
 __PRETTY_FUNCTION__));
}

if (result.isInvalid())
  return ExprError();

Expr *resultExpr = result.get();
return new (SemaRef.Context) SubstNonTypeTemplateParmExpr(
    resultExpr->getType(), resultExpr->getValueKind(), loc, parm, refParam,
    resultExpr);
1567}

1569ExprResult
1570TemplateInstantiator::TransformSubstNonTypeTemplateParmPackExpr(
                                        SubstNonTypeTemplateParmPackExpr *E) {
if (getSema().ArgumentPackSubstitutionIndex == -1) {
  // We aren't expanding the parameter pack, so just return ourselves.
  return E;
}

TemplateArgument Arg = E->getArgumentPack();
Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
return transformNonTypeTemplateParmRef(E->getParameterPack(),
                                       E->getParameterPackLocation(),
                                       Arg);
1582}

1584ExprResult
1585TemplateInstantiator::TransformSubstNonTypeTemplateParmExpr(
                                        SubstNonTypeTemplateParmExpr *E) {
ExprResult SubstReplacement = E->getReplacement();
if (!isa<ConstantExpr>(SubstReplacement.get()))
  SubstReplacement = TransformExpr(E->getReplacement());
if (SubstReplacement.isInvalid())
  return true;
QualType SubstType = TransformType(E->getParameterType(getSema().Context));
if (SubstType.isNull())
  return true;
// The type may have been previously dependent and not now, which means we
// might have to implicit cast the argument to the new type, for example:
// template<auto T, decltype(T) U>
// concept C = sizeof(U) == 4;
// void foo() requires C<2, 'a'> { }
// When normalizing foo(), we first form the normalized constraints of C:
// AtomicExpr(sizeof(U) == 4,
//            U=SubstNonTypeTemplateParmExpr(Param=U,
//                                           Expr=DeclRef(U),
//                                           Type=decltype(T)))
// Then we substitute T = 2, U = 'a' into the parameter mapping, and need to
// produce:
// AtomicExpr(sizeof(U) == 4,
//            U=SubstNonTypeTemplateParmExpr(Param=U,
//                                           Expr=ImpCast(
//                                               decltype(2),
//                                               SubstNTTPE(Param=U, Expr='a',
//                                                          Type=char)),
//                                           Type=decltype(2)))
// The call to CheckTemplateArgument here produces the ImpCast.
TemplateArgument Converted;
if (SemaRef.CheckTemplateArgument(E->getParameter(), SubstType,
                                  SubstReplacement.get(),
                                  Converted).isInvalid())
  return true;
return transformNonTypeTemplateParmRef(E->getParameter(),
                                       E->getExprLoc(), Converted);
1622}

1624ExprResult TemplateInstantiator::RebuildVarDeclRefExpr(VarDecl *PD,
                                                     SourceLocation Loc) {
DeclarationNameInfo NameInfo(PD->getDeclName(), Loc);
return getSema().BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo, PD);
1628}

1630ExprResult
1631TemplateInstantiator::TransformFunctionParmPackExpr(FunctionParmPackExpr *E) {
if (getSema().ArgumentPackSubstitutionIndex != -1) {
  // We can expand this parameter pack now.
  VarDecl *D = E->getExpansion(getSema().ArgumentPackSubstitutionIndex);
  VarDecl *VD = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), D));
  if (!VD)
    return ExprError();
  return RebuildVarDeclRefExpr(VD, E->getExprLoc());
}

QualType T = TransformType(E->getType());
if (T.isNull())
  return ExprError();

// Transform each of the parameter expansions into the corresponding
// parameters in the instantiation of the function decl.
SmallVector<VarDecl *, 8> Vars;
Vars.reserve(E->getNumExpansions());
for (FunctionParmPackExpr::iterator I = E->begin(), End = E->end();
     I != End; ++I) {
  VarDecl *D = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), *I));
  if (!D)
    return ExprError();
  Vars.push_back(D);
}

auto *PackExpr =
    FunctionParmPackExpr::Create(getSema().Context, T, E->getParameterPack(),
                                 E->getParameterPackLocation(), Vars);
getSema().MarkFunctionParmPackReferenced(PackExpr);
return PackExpr;
1662}

1664ExprResult
1665TemplateInstantiator::TransformFunctionParmPackRefExpr(DeclRefExpr *E,
                                                     VarDecl *PD) {
typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
  = getSema().CurrentInstantiationScope->findInstantiationOf(PD);
assert(Found && "no instantiation for parameter pack")(static_cast <bool> (Found && "no instantiation for parameter pack"
) ? void (0) : __assert_fail ("Found && \"no instantiation for parameter pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1670, __extension__
 __PRETTY_FUNCTION__));

Decl *TransformedDecl;
if (DeclArgumentPack *Pack = Found->dyn_cast<DeclArgumentPack *>()) {
  // If this is a reference to a function parameter pack which we can
  // substitute but can't yet expand, build a FunctionParmPackExpr for it.
  if (getSema().ArgumentPackSubstitutionIndex == -1) {
    QualType T = TransformType(E->getType());
    if (T.isNull())
      return ExprError();
    auto *PackExpr = FunctionParmPackExpr::Create(getSema().Context, T, PD,
                                                  E->getExprLoc(), *Pack);
    getSema().MarkFunctionParmPackReferenced(PackExpr);
    return PackExpr;
  }

  TransformedDecl = (*Pack)[getSema().ArgumentPackSubstitutionIndex];
} else {
  TransformedDecl = Found->get<Decl*>();
}

// We have either an unexpanded pack or a specific expansion.
return RebuildVarDeclRefExpr(cast<VarDecl>(TransformedDecl), E->getExprLoc());
1693}

1695ExprResult
1696TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) {
NamedDecl *D = E->getDecl();

// Handle references to non-type template parameters and non-type template
// parameter packs.
if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
  if (NTTP->getDepth() < TemplateArgs.getNumLevels())
    return TransformTemplateParmRefExpr(E, NTTP);

  // We have a non-type template parameter that isn't fully substituted;
  // FindInstantiatedDecl will find it in the local instantiation scope.
}

// Handle references to function parameter packs.
if (VarDecl *PD = dyn_cast<VarDecl>(D))
  if (PD->isParameterPack())
    return TransformFunctionParmPackRefExpr(E, PD);

return inherited::TransformDeclRefExpr(E);
1715}

1717ExprResult TemplateInstantiator::TransformCXXDefaultArgExpr(
  CXXDefaultArgExpr *E) {
assert(!cast<FunctionDecl>(E->getParam()->getDeclContext())->(static_cast <bool> (!cast<FunctionDecl>(E->getParam
()->getDeclContext())-> getDescribedFunctionTemplate() &&
 "Default arg expressions are never formed in dependent cases."
) ? void (0) : __assert_fail ("!cast<FunctionDecl>(E->getParam()->getDeclContext())-> getDescribedFunctionTemplate() && \"Default arg expressions are never formed in dependent cases.\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1721, __extension__
 __PRETTY_FUNCTION__))
           getDescribedFunctionTemplate() &&(static_cast <bool> (!cast<FunctionDecl>(E->getParam
()->getDeclContext())-> getDescribedFunctionTemplate() &&
 "Default arg expressions are never formed in dependent cases."
) ? void (0) : __assert_fail ("!cast<FunctionDecl>(E->getParam()->getDeclContext())-> getDescribedFunctionTemplate() && \"Default arg expressions are never formed in dependent cases.\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1721, __extension__
 __PRETTY_FUNCTION__))
       "Default arg expressions are never formed in dependent cases.")(static_cast <bool> (!cast<FunctionDecl>(E->getParam
()->getDeclContext())-> getDescribedFunctionTemplate() &&
 "Default arg expressions are never formed in dependent cases."
) ? void (0) : __assert_fail ("!cast<FunctionDecl>(E->getParam()->getDeclContext())-> getDescribedFunctionTemplate() && \"Default arg expressions are never formed in dependent cases.\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1721, __extension__
 __PRETTY_FUNCTION__));
return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(),
                         cast<FunctionDecl>(E->getParam()->getDeclContext()),
                                      E->getParam());
1725}

1727template<typename Fn>
1728QualType TemplateInstantiator::TransformFunctionProtoType(TypeLocBuilder &TLB,
                               FunctionProtoTypeLoc TL,
                               CXXRecordDecl *ThisContext,
                               Qualifiers ThisTypeQuals,
                               Fn TransformExceptionSpec) {
// We need a local instantiation scope for this function prototype.
LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
return inherited::TransformFunctionProtoType(
    TLB, TL, ThisContext, ThisTypeQuals, TransformExceptionSpec);
1737}

1739ParmVarDecl *
1740TemplateInstantiator::TransformFunctionTypeParam(ParmVarDecl *OldParm,
                                               int indexAdjustment,
                                             Optional<unsigned> NumExpansions,
                                               bool ExpectParameterPack) {
auto NewParm =
    SemaRef.SubstParmVarDecl(OldParm, TemplateArgs, indexAdjustment,
                             NumExpansions, ExpectParameterPack);
if (NewParm && SemaRef.getLangOpts().OpenCL)
  SemaRef.deduceOpenCLAddressSpace(NewParm);
return NewParm;
1750}

1752QualType
1753TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
                                              TemplateTypeParmTypeLoc TL) {
const TemplateTypeParmType *T = TL.getTypePtr();
if (T->getDepth() < TemplateArgs.getNumLevels()) {
  // Replace the template type parameter with its corresponding
  // template argument.

  // If the corresponding template argument is NULL or doesn't exist, it's
  // because we are performing instantiation from explicitly-specified
  // template arguments in a function template class, but there were some
  // arguments left unspecified.
  if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) {
    TemplateTypeParmTypeLoc NewTL
      = TLB.push<TemplateTypeParmTypeLoc>(TL.getType());
    NewTL.setNameLoc(TL.getNameLoc());
    return TL.getType();
  }

  TemplateArgument Arg = TemplateArgs(T->getDepth(), T->getIndex());

  if (TemplateArgs.isRewrite()) {
    // We're rewriting the template parameter as a reference to another
    // template parameter.
    if (Arg.getKind() == TemplateArgument::Pack) {
      assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&(static_cast <bool> (Arg.pack_size() == 1 && Arg
.pack_begin()->isPackExpansion() && "unexpected pack arguments in template rewrite"
) ? void (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() && \"unexpected pack arguments in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1778, __extension__
 __PRETTY_FUNCTION__))
             "unexpected pack arguments in template rewrite")(static_cast <bool> (Arg.pack_size() == 1 && Arg
.pack_begin()->isPackExpansion() && "unexpected pack arguments in template rewrite"
) ? void (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() && \"unexpected pack arguments in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1778, __extension__
 __PRETTY_FUNCTION__));
      Arg = Arg.pack_begin()->getPackExpansionPattern();
    }
    assert(Arg.getKind() == TemplateArgument::Type &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Type && "unexpected nontype template argument kind in template rewrite"
) ? void (0) : __assert_fail ("Arg.getKind() == TemplateArgument::Type && \"unexpected nontype template argument kind in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1782, __extension__
 __PRETTY_FUNCTION__))
           "unexpected nontype template argument kind in template rewrite")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Type && "unexpected nontype template argument kind in template rewrite"
) ? void (0) : __assert_fail ("Arg.getKind() == TemplateArgument::Type && \"unexpected nontype template argument kind in template rewrite\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1782, __extension__
 __PRETTY_FUNCTION__));
    QualType NewT = Arg.getAsType();
    assert(isa<TemplateTypeParmType>(NewT) &&(static_cast <bool> (isa<TemplateTypeParmType>(NewT
) && "type parm not rewritten to type parm") ? void (
0) : __assert_fail ("isa<TemplateTypeParmType>(NewT) && \"type parm not rewritten to type parm\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1785, __extension__
 __PRETTY_FUNCTION__))
           "type parm not rewritten to type parm")(static_cast <bool> (isa<TemplateTypeParmType>(NewT
) && "type parm not rewritten to type parm") ? void (
0) : __assert_fail ("isa<TemplateTypeParmType>(NewT) && \"type parm not rewritten to type parm\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1785, __extension__
 __PRETTY_FUNCTION__));
    auto NewTL = TLB.push<TemplateTypeParmTypeLoc>(NewT);
    NewTL.setNameLoc(TL.getNameLoc());
    return NewT;
  }

  if (T->isParameterPack()) {
    assert(Arg.getKind() == TemplateArgument::Pack &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1793, __extension__
 __PRETTY_FUNCTION__))
           "Missing argument pack")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Pack && "Missing argument pack") ? void (0) : __assert_fail
 ("Arg.getKind() == TemplateArgument::Pack && \"Missing argument pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1793, __extension__
 __PRETTY_FUNCTION__));

    if (getSema().ArgumentPackSubstitutionIndex == -1) {
      // We have the template argument pack, but we're not expanding the
      // enclosing pack expansion yet. Just save the template argument
      // pack for later substitution.
      QualType Result
        = getSema().Context.getSubstTemplateTypeParmPackType(T, Arg);
      SubstTemplateTypeParmPackTypeLoc NewTL
        = TLB.push<SubstTemplateTypeParmPackTypeLoc>(Result);
      NewTL.setNameLoc(TL.getNameLoc());
      return Result;
    }

    Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
  }

  assert(Arg.getKind() == TemplateArgument::Type &&(static_cast <bool> (Arg.getKind() == TemplateArgument::
Type && "Template argument kind mismatch") ? void (0)
 : __assert_fail ("Arg.getKind() == TemplateArgument::Type && \"Template argument kind mismatch\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1811, __extension__
 __PRETTY_FUNCTION__))
         "Template argument kind mismatch")(static_cast <bool> (Arg.getKind() == TemplateArgument::
Type && "Template argument kind mismatch") ? void (0)
 : __assert_fail ("Arg.getKind() == TemplateArgument::Type && \"Template argument kind mismatch\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1811, __extension__
 __PRETTY_FUNCTION__));

  QualType Replacement = Arg.getAsType();

  // TODO: only do this uniquing once, at the start of instantiation.
  QualType Result
    = getSema().Context.getSubstTemplateTypeParmType(T, Replacement);
  SubstTemplateTypeParmTypeLoc NewTL
    = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
  NewTL.setNameLoc(TL.getNameLoc());
  return Result;
}

// The template type parameter comes from an inner template (e.g.,
// the template parameter list of a member template inside the
// template we are instantiating). Create a new template type
// parameter with the template "level" reduced by one.
TemplateTypeParmDecl *NewTTPDecl = nullptr;
if (TemplateTypeParmDecl *OldTTPDecl = T->getDecl())
  NewTTPDecl = cast_or_null<TemplateTypeParmDecl>(
                                TransformDecl(TL.getNameLoc(), OldTTPDecl));

QualType Result = getSema().Context.getTemplateTypeParmType(
    T->getDepth() - TemplateArgs.getNumSubstitutedLevels(), T->getIndex(),
    T->isParameterPack(), NewTTPDecl);
TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
NewTL.setNameLoc(TL.getNameLoc());
return Result;
1839}

1841QualType
1842TemplateInstantiator::TransformSubstTemplateTypeParmPackType(
                                                          TypeLocBuilder &TLB,
                                       SubstTemplateTypeParmPackTypeLoc TL) {
if (getSema().ArgumentPackSubstitutionIndex == -1) {
  // We aren't expanding the parameter pack, so just return ourselves.
  SubstTemplateTypeParmPackTypeLoc NewTL
    = TLB.push<SubstTemplateTypeParmPackTypeLoc>(TL.getType());
  NewTL.setNameLoc(TL.getNameLoc());
  return TL.getType();
}

TemplateArgument Arg = TL.getTypePtr()->getArgumentPack();
Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
QualType Result = Arg.getAsType();

Result = getSema().Context.getSubstTemplateTypeParmType(
                                    TL.getTypePtr()->getReplacedParameter(),
                                                        Result);
SubstTemplateTypeParmTypeLoc NewTL
  = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
NewTL.setNameLoc(TL.getNameLoc());
return Result;
1864}

1866template<typename EntityPrinter>
1867static concepts::Requirement::SubstitutionDiagnostic *
1868createSubstDiag(Sema &S, TemplateDeductionInfo &Info, EntityPrinter Printer) {
SmallString<128> Message;
SourceLocation ErrorLoc;
if (Info.hasSFINAEDiagnostic()) {
  PartialDiagnosticAt PDA(SourceLocation(),
                          PartialDiagnostic::NullDiagnostic{});
  Info.takeSFINAEDiagnostic(PDA);
  PDA.second.EmitToString(S.getDiagnostics(), Message);
  ErrorLoc = PDA.first;
} else {
  ErrorLoc = Info.getLocation();
}
char *MessageBuf = new (S.Context) char[Message.size()];
std::copy(Message.begin(), Message.end(), MessageBuf);
SmallString<128> Entity;
llvm::raw_svector_ostream OS(Entity);
Printer(OS);
char *EntityBuf = new (S.Context) char[Entity.size()];
std::copy(Entity.begin(), Entity.end(), EntityBuf);
return new (S.Context) concepts::Requirement::SubstitutionDiagnostic{
    StringRef(EntityBuf, Entity.size()), ErrorLoc,
    StringRef(MessageBuf, Message.size())};
1890}

1892concepts::TypeRequirement *
1893TemplateInstantiator::TransformTypeRequirement(concepts::TypeRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;
if (Req->isSubstitutionFailure()) {
  if (AlwaysRebuild())
    return RebuildTypeRequirement(
            Req->getSubstitutionDiagnostic());
  return Req;
}

Sema::SFINAETrap Trap(SemaRef);
TemplateDeductionInfo Info(Req->getType()->getTypeLoc().getBeginLoc());
Sema::InstantiatingTemplate TypeInst(SemaRef,
    Req->getType()->getTypeLoc().getBeginLoc(), Req, Info,
    Req->getType()->getTypeLoc().getSourceRange());
if (TypeInst.isInvalid())
  return nullptr;
TypeSourceInfo *TransType = TransformType(Req->getType());
if (!TransType || Trap.hasErrorOccurred())
  return RebuildTypeRequirement(createSubstDiag(SemaRef, Info,
      [&] (llvm::raw_ostream& OS) {
          Req->getType()->getType().print(OS, SemaRef.getPrintingPolicy());
      }));
return RebuildTypeRequirement(TransType);
1917}

1919concepts::ExprRequirement *
1920TemplateInstantiator::TransformExprRequirement(concepts::ExprRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;

Sema::SFINAETrap Trap(SemaRef);

llvm::PointerUnion<Expr *, concepts::Requirement::SubstitutionDiagnostic *>
    TransExpr;
if (Req->isExprSubstitutionFailure())
  TransExpr = Req->getExprSubstitutionDiagnostic();
else {
  Expr *E = Req->getExpr();
  TemplateDeductionInfo Info(E->getBeginLoc());
  Sema::InstantiatingTemplate ExprInst(SemaRef, E->getBeginLoc(), Req, Info,
                                       E->getSourceRange());
  if (ExprInst.isInvalid())
    return nullptr;
  ExprResult TransExprRes = TransformExpr(E);
  if (!TransExprRes.isInvalid() && !Trap.hasErrorOccurred() &&
      TransExprRes.get()->hasPlaceholderType())
    TransExprRes = SemaRef.CheckPlaceholderExpr(TransExprRes.get());
  if (TransExprRes.isInvalid() || Trap.hasErrorOccurred())
    TransExpr = createSubstDiag(SemaRef, Info, [&](llvm::raw_ostream &OS) {
      E->printPretty(OS, nullptr, SemaRef.getPrintingPolicy());
    });
  else
    TransExpr = TransExprRes.get();
}

llvm::Optional<concepts::ExprRequirement::ReturnTypeRequirement> TransRetReq;
const auto &RetReq = Req->getReturnTypeRequirement();
if (RetReq.isEmpty())
  TransRetReq.emplace();
else if (RetReq.isSubstitutionFailure())
  TransRetReq.emplace(RetReq.getSubstitutionDiagnostic());
else if (RetReq.isTypeConstraint()) {
  TemplateParameterList *OrigTPL =
      RetReq.getTypeConstraintTemplateParameterList();
  TemplateDeductionInfo Info(OrigTPL->getTemplateLoc());
  Sema::InstantiatingTemplate TPLInst(SemaRef, OrigTPL->getTemplateLoc(),
                                      Req, Info, OrigTPL->getSourceRange());
  if (TPLInst.isInvalid())
    return nullptr;
  TemplateParameterList *TPL =
      TransformTemplateParameterList(OrigTPL);
  if (!TPL)
    TransRetReq.emplace(createSubstDiag(SemaRef, Info,
        [&] (llvm::raw_ostream& OS) {
            RetReq.getTypeConstraint()->getImmediatelyDeclaredConstraint()
                ->printPretty(OS, nullptr, SemaRef.getPrintingPolicy());
        }));
  else {
    TPLInst.Clear();
    TransRetReq.emplace(TPL);
  }
}
assert(TransRetReq.hasValue() &&(static_cast <bool> (TransRetReq.hasValue() && "All code paths leading here must set TransRetReq"
) ? void (0) : __assert_fail ("TransRetReq.hasValue() && \"All code paths leading here must set TransRetReq\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1977, __extension__
 __PRETTY_FUNCTION__))
       "All code paths leading here must set TransRetReq")(static_cast <bool> (TransRetReq.hasValue() && "All code paths leading here must set TransRetReq"
) ? void (0) : __assert_fail ("TransRetReq.hasValue() && \"All code paths leading here must set TransRetReq\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 1977, __extension__
 __PRETTY_FUNCTION__));
if (Expr *E = TransExpr.dyn_cast<Expr *>())
  return RebuildExprRequirement(E, Req->isSimple(), Req->getNoexceptLoc(),
                                std::move(*TransRetReq));
return RebuildExprRequirement(
    TransExpr.get<concepts::Requirement::SubstitutionDiagnostic *>(),
    Req->isSimple(), Req->getNoexceptLoc(), std::move(*TransRetReq));
1984}

1986concepts::NestedRequirement *
1987TemplateInstantiator::TransformNestedRequirement(
  concepts::NestedRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;
if (Req->isSubstitutionFailure()) {
  if (AlwaysRebuild())
    return RebuildNestedRequirement(
        Req->getSubstitutionDiagnostic());
  return Req;
}
Sema::InstantiatingTemplate ReqInst(SemaRef,
    Req->getConstraintExpr()->getBeginLoc(), Req,
    Sema::InstantiatingTemplate::ConstraintsCheck{},
    Req->getConstraintExpr()->getSourceRange());

ExprResult TransConstraint;
TemplateDeductionInfo Info(Req->getConstraintExpr()->getBeginLoc());
{
  EnterExpressionEvaluationContext ContextRAII(
      SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  Sema::SFINAETrap Trap(SemaRef);
  Sema::InstantiatingTemplate ConstrInst(SemaRef,
      Req->getConstraintExpr()->getBeginLoc(), Req, Info,
      Req->getConstraintExpr()->getSourceRange());
  if (ConstrInst.isInvalid())
    return nullptr;
  TransConstraint = TransformExpr(Req->getConstraintExpr());
  if (TransConstraint.isInvalid() || Trap.hasErrorOccurred())
    return RebuildNestedRequirement(createSubstDiag(SemaRef, Info,
        [&] (llvm::raw_ostream& OS) {
            Req->getConstraintExpr()->printPretty(OS, nullptr,
                                                  SemaRef.getPrintingPolicy());
        }));
}
return RebuildNestedRequirement(TransConstraint.get());
2022}


2025/// Perform substitution on the type T with a given set of template
2026/// arguments.
2027///
2028/// This routine substitutes the given template arguments into the
2029/// type T and produces the instantiated type.
2030///
2031/// \param T the type into which the template arguments will be
2032/// substituted. If this type is not dependent, it will be returned
2033/// immediately.
2034///
2035/// \param Args the template arguments that will be
2036/// substituted for the top-level template parameters within T.
2037///
2038/// \param Loc the location in the source code where this substitution
2039/// is being performed. It will typically be the location of the
2040/// declarator (if we're instantiating the type of some declaration)
2041/// or the location of the type in the source code (if, e.g., we're
2042/// instantiating the type of a cast expression).
2043///
2044/// \param Entity the name of the entity associated with a declaration
2045/// being instantiated (if any). May be empty to indicate that there
2046/// is no such entity (if, e.g., this is a type that occurs as part of
2047/// a cast expression) or that the entity has no name (e.g., an
2048/// unnamed function parameter).
2049///
2050/// \param AllowDeducedTST Whether a DeducedTemplateSpecializationType is
2051/// acceptable as the top level type of the result.
2052///
2053/// \returns If the instantiation succeeds, the instantiated
2054/// type. Otherwise, produces diagnostics and returns a NULL type.
2055TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity,
                              bool AllowDeducedTST) {
assert(!CodeSynthesisContexts.empty() &&(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2062, __extension__
 __PRETTY_FUNCTION__))
       "Cannot perform an instantiation without some context on the "(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2062, __extension__
 __PRETTY_FUNCTION__))
       "instantiation stack")(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2062, __extension__
 __PRETTY_FUNCTION__));

if (!T->getType()->isInstantiationDependentType() &&
    !T->getType()->isVariablyModifiedType())
  return T;

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
return AllowDeducedTST ? Instantiator.TransformTypeWithDeducedTST(T)
                       : Instantiator.TransformType(T);
2071}

2073TypeSourceInfo *Sema::SubstType(TypeLoc TL,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity) {
assert(!CodeSynthesisContexts.empty() &&(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2079, __extension__
 __PRETTY_FUNCTION__))
       "Cannot perform an instantiation without some context on the "(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2079, __extension__
 __PRETTY_FUNCTION__))
       "instantiation stack")(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2079, __extension__
 __PRETTY_FUNCTION__));

if (TL.getType().isNull())
  return nullptr;

if (!TL.getType()->isInstantiationDependentType() &&
    !TL.getType()->isVariablyModifiedType()) {
  // FIXME: Make a copy of the TypeLoc data here, so that we can
  // return a new TypeSourceInfo. Inefficient!
  TypeLocBuilder TLB;
  TLB.pushFullCopy(TL);
  return TLB.getTypeSourceInfo(Context, TL.getType());
}

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
TypeLocBuilder TLB;
TLB.reserve(TL.getFullDataSize());
QualType Result = Instantiator.TransformType(TLB, TL);
if (Result.isNull())
  return nullptr;

return TLB.getTypeSourceInfo(Context, Result);
2101}

2103/// Deprecated form of the above.
2104QualType Sema::SubstType(QualType T,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       SourceLocation Loc, DeclarationName Entity) {
assert(!CodeSynthesisContexts.empty() &&(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2109, __extension__
 __PRETTY_FUNCTION__))
       "Cannot perform an instantiation without some context on the "(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2109, __extension__
 __PRETTY_FUNCTION__))
       "instantiation stack")(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2109, __extension__
 __PRETTY_FUNCTION__));

// If T is not a dependent type or a variably-modified type, there
// is nothing to do.
if (!T->isInstantiationDependentType() && !T->isVariablyModifiedType())
  return T;

TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity);
return Instantiator.TransformType(T);
2118}

2120static bool NeedsInstantiationAsFunctionType(TypeSourceInfo *T) {
if (T->getType()->isInstantiationDependentType() ||
    T->getType()->isVariablyModifiedType())
  return true;

TypeLoc TL = T->getTypeLoc().IgnoreParens();
if (!TL.getAs<FunctionProtoTypeLoc>())
  return false;

FunctionProtoTypeLoc FP = TL.castAs<FunctionProtoTypeLoc>();
for (ParmVarDecl *P : FP.getParams()) {
  // This must be synthesized from a typedef.
  if (!P) continue;

  // If there are any parameters, a new TypeSourceInfo that refers to the
  // instantiated parameters must be built.
  return true;
}

return false;
2140}

2142/// A form of SubstType intended specifically for instantiating the
2143/// type of a FunctionDecl.  Its purpose is solely to force the
2144/// instantiation of default-argument expressions and to avoid
2145/// instantiating an exception-specification.
2146TypeSourceInfo *Sema::SubstFunctionDeclType(TypeSourceInfo *T,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity,
                              CXXRecordDecl *ThisContext,
                              Qualifiers ThisTypeQuals) {
assert(!CodeSynthesisContexts.empty() &&(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2154, __extension__
 __PRETTY_FUNCTION__))
       "Cannot perform an instantiation without some context on the "(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2154, __extension__
 __PRETTY_FUNCTION__))
       "instantiation stack")(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2154, __extension__
 __PRETTY_FUNCTION__));

if (!NeedsInstantiationAsFunctionType(T))
  return T;

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);

TypeLocBuilder TLB;

TypeLoc TL = T->getTypeLoc();
TLB.reserve(TL.getFullDataSize());

QualType Result;

if (FunctionProtoTypeLoc Proto =
        TL.IgnoreParens().getAs<FunctionProtoTypeLoc>()) {
  // Instantiate the type, other than its exception specification. The
  // exception specification is instantiated in InitFunctionInstantiation
  // once we've built the FunctionDecl.
  // FIXME: Set the exception specification to EST_Uninstantiated here,
  // instead of rebuilding the function type again later.
  Result = Instantiator.TransformFunctionProtoType(
      TLB, Proto, ThisContext, ThisTypeQuals,
      [](FunctionProtoType::ExceptionSpecInfo &ESI,
         bool &Changed) { return false; });
} else {
  Result = Instantiator.TransformType(TLB, TL);
}
if (Result.isNull())
  return nullptr;

return TLB.getTypeSourceInfo(Context, Result);
2186}

2188bool Sema::SubstExceptionSpec(SourceLocation Loc,
                            FunctionProtoType::ExceptionSpecInfo &ESI,
                            SmallVectorImpl<QualType> &ExceptionStorage,
                            const MultiLevelTemplateArgumentList &Args) {
assert(ESI.Type != EST_Uninstantiated)(static_cast <bool> (ESI.Type != EST_Uninstantiated) ? void
 (0) : __assert_fail ("ESI.Type != EST_Uninstantiated", "clang/lib/Sema/SemaTemplateInstantiate.cpp"
, 2192, __extension__ __PRETTY_FUNCTION__));

bool Changed = false;
TemplateInstantiator Instantiator(*this, Args, Loc, DeclarationName());
return Instantiator.TransformExceptionSpec(Loc, ESI, ExceptionStorage,
                                           Changed);
2198}

2200void Sema::SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto,
                            const MultiLevelTemplateArgumentList &Args) {
FunctionProtoType::ExceptionSpecInfo ESI =
    Proto->getExtProtoInfo().ExceptionSpec;

SmallVector<QualType, 4> ExceptionStorage;
if (SubstExceptionSpec(New->getTypeSourceInfo()->getTypeLoc().getEndLoc(),
                       ESI, ExceptionStorage, Args))
  // On error, recover by dropping the exception specification.
  ESI.Type = EST_None;

UpdateExceptionSpec(New, ESI);
2212}

2214namespace {

struct GetContainedInventedTypeParmVisitor :
  public TypeVisitor<GetContainedInventedTypeParmVisitor,
                     TemplateTypeParmDecl *> {
  using TypeVisitor<GetContainedInventedTypeParmVisitor,
                    TemplateTypeParmDecl *>::Visit;

  TemplateTypeParmDecl *Visit(QualType T) {
    if (T.isNull())
      return nullptr;
    return Visit(T.getTypePtr());
  }
  // The deduced type itself.
  TemplateTypeParmDecl *VisitTemplateTypeParmType(
      const TemplateTypeParmType *T) {
    if (!T->getDecl() || !T->getDecl()->isImplicit())
      return nullptr;
    return T->getDecl();
  }

  // Only these types can contain 'auto' types, and subsequently be replaced
  // by references to invented parameters.

  TemplateTypeParmDecl *VisitElaboratedType(const ElaboratedType *T) {
    return Visit(T->getNamedType());
  }

  TemplateTypeParmDecl *VisitPointerType(const PointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitBlockPointerType(const BlockPointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitReferenceType(const ReferenceType *T) {
    return Visit(T->getPointeeTypeAsWritten());
  }

  TemplateTypeParmDecl *VisitMemberPointerType(const MemberPointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitArrayType(const ArrayType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitDependentSizedExtVectorType(
    const DependentSizedExtVectorType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitVectorType(const VectorType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitFunctionProtoType(const FunctionProtoType *T) {
    return VisitFunctionType(T);
  }

  TemplateTypeParmDecl *VisitFunctionType(const FunctionType *T) {
    return Visit(T->getReturnType());
  }

  TemplateTypeParmDecl *VisitParenType(const ParenType *T) {
    return Visit(T->getInnerType());
  }

  TemplateTypeParmDecl *VisitAttributedType(const AttributedType *T) {
    return Visit(T->getModifiedType());
  }

  TemplateTypeParmDecl *VisitMacroQualifiedType(const MacroQualifiedType *T) {
    return Visit(T->getUnderlyingType());
  }

  TemplateTypeParmDecl *VisitAdjustedType(const AdjustedType *T) {
    return Visit(T->getOriginalType());
  }

  TemplateTypeParmDecl *VisitPackExpansionType(const PackExpansionType *T) {
    return Visit(T->getPattern());
  }
};

2300} // namespace

2302bool Sema::SubstTypeConstraint(
  TemplateTypeParmDecl *Inst, const TypeConstraint *TC,
  const MultiLevelTemplateArgumentList &TemplateArgs) {
const ASTTemplateArgumentListInfo *TemplArgInfo =
    TC->getTemplateArgsAsWritten();
TemplateArgumentListInfo InstArgs;

if (TemplArgInfo) {
  InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
  InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
  if (SubstTemplateArguments(TemplArgInfo->arguments(), TemplateArgs,
                             InstArgs))
    return true;
}
return AttachTypeConstraint(
    TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
    TC->getNamedConcept(), &InstArgs, Inst,
    Inst->isParameterPack()
        ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
              ->getEllipsisLoc()
        : SourceLocation());
2323}

2325ParmVarDecl *Sema::SubstParmVarDecl(ParmVarDecl *OldParm,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                                  int indexAdjustment,
                                  Optional<unsigned> NumExpansions,
                                  bool ExpectParameterPack) {
TypeSourceInfo *OldDI = OldParm->getTypeSourceInfo();
TypeSourceInfo *NewDI = nullptr;

TypeLoc OldTL = OldDI->getTypeLoc();
if (PackExpansionTypeLoc ExpansionTL = OldTL.getAs<PackExpansionTypeLoc>()) {

  // We have a function parameter pack. Substitute into the pattern of the
  // expansion.
  NewDI = SubstType(ExpansionTL.getPatternLoc(), TemplateArgs,
                    OldParm->getLocation(), OldParm->getDeclName());
  if (!NewDI)
    return nullptr;

  if (NewDI->getType()->containsUnexpandedParameterPack()) {
    // We still have unexpanded parameter packs, which means that
    // our function parameter is still a function parameter pack.
    // Therefore, make its type a pack expansion type.
    NewDI = CheckPackExpansion(NewDI, ExpansionTL.getEllipsisLoc(),
                               NumExpansions);
  } else if (ExpectParameterPack) {
    // We expected to get a parameter pack but didn't (because the type
    // itself is not a pack expansion type), so complain. This can occur when
    // the substitution goes through an alias template that "loses" the
    // pack expansion.
    Diag(OldParm->getLocation(),
         diag::err_function_parameter_pack_without_parameter_packs)
      << NewDI->getType();
    return nullptr;
  }
} else {
  NewDI = SubstType(OldDI, TemplateArgs, OldParm->getLocation(),
                    OldParm->getDeclName());
}

if (!NewDI)
  return nullptr;

if (NewDI->getType()->isVoidType()) {
  Diag(OldParm->getLocation(), diag::err_param_with_void_type);
  return nullptr;
}

// In abbreviated templates, TemplateTypeParmDecls with possible
// TypeConstraints are created when the parameter list is originally parsed.
// The TypeConstraints can therefore reference other functions parameters in
// the abbreviated function template, which is why we must instantiate them
// here, when the instantiated versions of those referenced parameters are in
// scope.
if (TemplateTypeParmDecl *TTP =
        GetContainedInventedTypeParmVisitor().Visit(OldDI->getType())) {
  if (const TypeConstraint *TC = TTP->getTypeConstraint()) {
    auto *Inst = cast_or_null<TemplateTypeParmDecl>(
        FindInstantiatedDecl(TTP->getLocation(), TTP, TemplateArgs));
    // We will first get here when instantiating the abbreviated function
    // template's described function, but we might also get here later.
    // Make sure we do not instantiate the TypeConstraint more than once.
    if (Inst && !Inst->getTypeConstraint()) {
      // TODO: Concepts: do not instantiate the constraint (delayed constraint
      // substitution)
      if (SubstTypeConstraint(Inst, TC, TemplateArgs))
        return nullptr;
    }
  }
}

ParmVarDecl *NewParm = CheckParameter(Context.getTranslationUnitDecl(),
                                      OldParm->getInnerLocStart(),
                                      OldParm->getLocation(),
                                      OldParm->getIdentifier(),
                                      NewDI->getType(), NewDI,
                                      OldParm->getStorageClass());
if (!NewParm)
  return nullptr;

// Mark the (new) default argument as uninstantiated (if any).
if (OldParm->hasUninstantiatedDefaultArg()) {
  Expr *Arg = OldParm->getUninstantiatedDefaultArg();
  NewParm->setUninstantiatedDefaultArg(Arg);
} else if (OldParm->hasUnparsedDefaultArg()) {
  NewParm->setUnparsedDefaultArg();
  UnparsedDefaultArgInstantiations[OldParm].push_back(NewParm);
} else if (Expr *Arg = OldParm->getDefaultArg()) {
  FunctionDecl *OwningFunc = cast<FunctionDecl>(OldParm->getDeclContext());
  if (OwningFunc->isInLocalScopeForInstantiation()) {
    // Instantiate default arguments for methods of local classes (DR1484)
    // and non-defining declarations.
    Sema::ContextRAII SavedContext(*this, OwningFunc);
    LocalInstantiationScope Local(*this, true);
    ExprResult NewArg = SubstExpr(Arg, TemplateArgs);
    if (NewArg.isUsable()) {
      // It would be nice if we still had this.
      SourceLocation EqualLoc = NewArg.get()->getBeginLoc();
      ExprResult Result =
          ConvertParamDefaultArgument(NewParm, NewArg.get(), EqualLoc);
      if (Result.isInvalid())
        return nullptr;

      SetParamDefaultArgument(NewParm, Result.getAs<Expr>(), EqualLoc);
    }
  } else {
    // FIXME: if we non-lazily instantiated non-dependent default args for
    // non-dependent parameter types we could remove a bunch of duplicate
    // conversion warnings for such arguments.
    NewParm->setUninstantiatedDefaultArg(Arg);
  }
}

NewParm->setHasInheritedDefaultArg(OldParm->hasInheritedDefaultArg());

if (OldParm->isParameterPack() && !NewParm->isParameterPack()) {
  // Add the new parameter to the instantiated parameter pack.
  CurrentInstantiationScope->InstantiatedLocalPackArg(OldParm, NewParm);
} else {
  // Introduce an Old -> New mapping
  CurrentInstantiationScope->InstantiatedLocal(OldParm, NewParm);
}

// FIXME: OldParm may come from a FunctionProtoType, in which case CurContext
// can be anything, is this right ?
NewParm->setDeclContext(CurContext);

NewParm->setScopeInfo(OldParm->getFunctionScopeDepth(),
                      OldParm->getFunctionScopeIndex() + indexAdjustment);

InstantiateAttrs(TemplateArgs, OldParm, NewParm);

return NewParm;
2457}

2459/// Substitute the given template arguments into the given set of
2460/// parameters, producing the set of parameter types that would be generated
2461/// from such a substitution.
2462bool Sema::SubstParmTypes(
  SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
  const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
  const MultiLevelTemplateArgumentList &TemplateArgs,
  SmallVectorImpl<QualType> &ParamTypes,
  SmallVectorImpl<ParmVarDecl *> *OutParams,
  ExtParameterInfoBuilder &ParamInfos) {
assert(!CodeSynthesisContexts.empty() &&(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2471, __extension__
 __PRETTY_FUNCTION__))
       "Cannot perform an instantiation without some context on the "(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2471, __extension__
 __PRETTY_FUNCTION__))
       "instantiation stack")(static_cast <bool> (!CodeSynthesisContexts.empty() &&
 "Cannot perform an instantiation without some context on the "
 "instantiation stack") ? void (0) : __assert_fail ("!CodeSynthesisContexts.empty() && \"Cannot perform an instantiation without some context on the \" \"instantiation stack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2471, __extension__
 __PRETTY_FUNCTION__));

TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
                                  DeclarationName());
return Instantiator.TransformFunctionTypeParams(
    Loc, Params, nullptr, ExtParamInfos, ParamTypes, OutParams, ParamInfos);
2477}

2479/// Perform substitution on the base class specifiers of the
2480/// given class template specialization.
2481///
2482/// Produces a diagnostic and returns true on error, returns false and
2483/// attaches the instantiated base classes to the class template
2484/// specialization if successful.
2485bool
2486Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                        CXXRecordDecl *Pattern,
                        const MultiLevelTemplateArgumentList &TemplateArgs) {
bool Invalid = false;
SmallVector<CXXBaseSpecifier*, 4> InstantiatedBases;
for (const auto &Base : Pattern->bases()) {
  if (!Base.getType()->isDependentType()) {
    if (const CXXRecordDecl *RD = Base.getType()->getAsCXXRecordDecl()) {
      if (RD->isInvalidDecl())
        Instantiation->setInvalidDecl();
    }
    InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(Base));
    continue;
  }

  SourceLocation EllipsisLoc;
  TypeSourceInfo *BaseTypeLoc;
  if (Base.isPackExpansion()) {
    // This is a pack expansion. See whether we should expand it now, or
    // wait until later.
    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
    collectUnexpandedParameterPacks(Base.getTypeSourceInfo()->getTypeLoc(),
                                    Unexpanded);
    bool ShouldExpand = false;
    bool RetainExpansion = false;
    Optional<unsigned> NumExpansions;
    if (CheckParameterPacksForExpansion(Base.getEllipsisLoc(),
                                        Base.getSourceRange(),
                                        Unexpanded,
                                        TemplateArgs, ShouldExpand,
                                        RetainExpansion,
                                        NumExpansions)) {
      Invalid = true;
      continue;
    }

    // If we should expand this pack expansion now, do so.
    if (ShouldExpand) {
      for (unsigned I = 0; I != *NumExpansions; ++I) {
          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);

        TypeSourceInfo *BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                                                TemplateArgs,
                                            Base.getSourceRange().getBegin(),
                                                DeclarationName());
        if (!BaseTypeLoc) {
          Invalid = true;
          continue;
        }

        if (CXXBaseSpecifier *InstantiatedBase
              = CheckBaseSpecifier(Instantiation,
                                   Base.getSourceRange(),
                                   Base.isVirtual(),
                                   Base.getAccessSpecifierAsWritten(),
                                   BaseTypeLoc,
                                   SourceLocation()))
          InstantiatedBases.push_back(InstantiatedBase);
        else
          Invalid = true;
      }

      continue;
    }

    // The resulting base specifier will (still) be a pack expansion.
    EllipsisLoc = Base.getEllipsisLoc();
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
    BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                            TemplateArgs,
                            Base.getSourceRange().getBegin(),
                            DeclarationName());
  } else {
    BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                            TemplateArgs,
                            Base.getSourceRange().getBegin(),
                            DeclarationName());
  }

  if (!BaseTypeLoc) {
    Invalid = true;
    continue;
  }

  if (CXXBaseSpecifier *InstantiatedBase
        = CheckBaseSpecifier(Instantiation,
                             Base.getSourceRange(),
                             Base.isVirtual(),
                             Base.getAccessSpecifierAsWritten(),
                             BaseTypeLoc,
                             EllipsisLoc))
    InstantiatedBases.push_back(InstantiatedBase);
  else
    Invalid = true;
}

if (!Invalid && AttachBaseSpecifiers(Instantiation, InstantiatedBases))
  Invalid = true;

return Invalid;
2586}

2588// Defined via #include from SemaTemplateInstantiateDecl.cpp
2589namespace clang {
namespace sema {
  Attr *instantiateTemplateAttribute(const Attr *At, ASTContext &C, Sema &S,
                          const MultiLevelTemplateArgumentList &TemplateArgs);
  Attr *instantiateTemplateAttributeForDecl(
      const Attr *At, ASTContext &C, Sema &S,
      const MultiLevelTemplateArgumentList &TemplateArgs);
}
2597}

2599/// Instantiate the definition of a class from a given pattern.
2600///
2601/// \param PointOfInstantiation The point of instantiation within the
2602/// source code.
2603///
2604/// \param Instantiation is the declaration whose definition is being
2605/// instantiated. This will be either a class template specialization
2606/// or a member class of a class template specialization.
2607///
2608/// \param Pattern is the pattern from which the instantiation
2609/// occurs. This will be either the declaration of a class template or
2610/// the declaration of a member class of a class template.
2611///
2612/// \param TemplateArgs The template arguments to be substituted into
2613/// the pattern.
2614///
2615/// \param TSK the kind of implicit or explicit instantiation to perform.
2616///
2617/// \param Complain whether to complain if the class cannot be instantiated due
2618/// to the lack of a definition.
2619///
2620/// \returns true if an error occurred, false otherwise.
2621bool
2622Sema::InstantiateClass(SourceLocation PointOfInstantiation,
                     CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     TemplateSpecializationKind TSK,
                     bool Complain) {
CXXRecordDecl *PatternDef
  = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Instantiation,
                              Instantiation->getInstantiatedFromMemberClass(),
                                   Pattern, PatternDef, TSK, Complain))
  return true;

llvm::TimeTraceScope TimeScope("InstantiateClass", [&]() {
  std::string Name;
  llvm::raw_string_ostream OS(Name);
  Instantiation->getNameForDiagnostic(OS, getPrintingPolicy(),
                                      /*Qualified=*/true);
  return Name;
});

Pattern = PatternDef;

// Record the point of instantiation.
if (MemberSpecializationInfo *MSInfo
      = Instantiation->getMemberSpecializationInfo()) {
  MSInfo->setTemplateSpecializationKind(TSK);
  MSInfo->setPointOfInstantiation(PointOfInstantiation);
} else if (ClassTemplateSpecializationDecl *Spec
      = dyn_cast<ClassTemplateSpecializationDecl>(Instantiation)) {
  Spec->setTemplateSpecializationKind(TSK);
  Spec->setPointOfInstantiation(PointOfInstantiation);
}

InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
if (Inst.isInvalid())
  return true;
assert(!Inst.isAlreadyInstantiating() && "should have been caught by caller")(static_cast <bool> (!Inst.isAlreadyInstantiating() &&
 "should have been caught by caller") ? void (0) : __assert_fail
 ("!Inst.isAlreadyInstantiating() && \"should have been caught by caller\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2658, __extension__
 __PRETTY_FUNCTION__));
PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(),
                                    "instantiating class definition");

// Enter the scope of this instantiation. We don't use
// PushDeclContext because we don't have a scope.
ContextRAII SavedContext(*this, Instantiation);
EnterExpressionEvaluationContext EvalContext(
    *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);

// If this is an instantiation of a local class, merge this local
// instantiation scope with the enclosing scope. Otherwise, every
// instantiation of a class has its own local instantiation scope.
bool MergeWithParentScope = !Instantiation->isDefinedOutsideFunctionOrMethod();
LocalInstantiationScope Scope(*this, MergeWithParentScope);

// Some class state isn't processed immediately but delayed till class
// instantiation completes. We may not be ready to handle any delayed state
// already on the stack as it might correspond to a different class, so save
// it now and put it back later.
SavePendingParsedClassStateRAII SavedPendingParsedClassState(*this);

// Pull attributes from the pattern onto the instantiation.
InstantiateAttrs(TemplateArgs, Pattern, Instantiation);

// Start the definition of this instantiation.
Instantiation->startDefinition();

// The instantiation is visible here, even if it was first declared in an
// unimported module.
Instantiation->setVisibleDespiteOwningModule();

// FIXME: This loses the as-written tag kind for an explicit instantiation.
Instantiation->setTagKind(Pattern->getTagKind());

// Do substitution on the base class specifiers.
if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs))
  Instantiation->setInvalidDecl();

TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs);
SmallVector<Decl*, 4> Fields;
// Delay instantiation of late parsed attributes.
LateInstantiatedAttrVec LateAttrs;
Instantiator.enableLateAttributeInstantiation(&LateAttrs);

bool MightHaveConstexprVirtualFunctions = false;
for (auto *Member : Pattern->decls()) {
  // Don't instantiate members not belonging in this semantic context.
  // e.g. for:
  // @code
  //    template <int i> class A {
  //      class B *g;
  //    };
  // @endcode
  // 'class B' has the template as lexical context but semantically it is
  // introduced in namespace scope.
  if (Member->getDeclContext() != Pattern)
    continue;

  // BlockDecls can appear in a default-member-initializer. They must be the
  // child of a BlockExpr, so we only know how to instantiate them from there.
  // Similarly, lambda closure types are recreated when instantiating the
  // corresponding LambdaExpr.
  if (isa<BlockDecl>(Member) ||
      (isa<CXXRecordDecl>(Member) && cast<CXXRecordDecl>(Member)->isLambda()))
    continue;

  if (Member->isInvalidDecl()) {
    Instantiation->setInvalidDecl();
    continue;
  }

  Decl *NewMember = Instantiator.Visit(Member);
  if (NewMember) {
    if (FieldDecl *Field = dyn_cast<FieldDecl>(NewMember)) {
      Fields.push_back(Field);
    } else if (EnumDecl *Enum = dyn_cast<EnumDecl>(NewMember)) {
      // C++11 [temp.inst]p1: The implicit instantiation of a class template
      // specialization causes the implicit instantiation of the definitions
      // of unscoped member enumerations.
      // Record a point of instantiation for this implicit instantiation.
      if (TSK == TSK_ImplicitInstantiation && !Enum->isScoped() &&
          Enum->isCompleteDefinition()) {
        MemberSpecializationInfo *MSInfo =Enum->getMemberSpecializationInfo();
        assert(MSInfo && "no spec info for member enum specialization")(static_cast <bool> (MSInfo && "no spec info for member enum specialization"
) ? void (0) : __assert_fail ("MSInfo && \"no spec info for member enum specialization\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2742, __extension__
 __PRETTY_FUNCTION__));
        MSInfo->setTemplateSpecializationKind(TSK_ImplicitInstantiation);
        MSInfo->setPointOfInstantiation(PointOfInstantiation);
      }
    } else if (StaticAssertDecl *SA = dyn_cast<StaticAssertDecl>(NewMember)) {
      if (SA->isFailed()) {
        // A static_assert failed. Bail out; instantiating this
        // class is probably not meaningful.
        Instantiation->setInvalidDecl();
        break;
      }
    } else if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewMember)) {
      if (MD->isConstexpr() && !MD->getFriendObjectKind() &&
          (MD->isVirtualAsWritten() || Instantiation->getNumBases()))
        MightHaveConstexprVirtualFunctions = true;
    }

    if (NewMember->isInvalidDecl())
      Instantiation->setInvalidDecl();
  } else {
    // FIXME: Eventually, a NULL return will mean that one of the
    // instantiations was a semantic disaster, and we'll want to mark the
    // declaration invalid.
    // For now, we expect to skip some members that we can't yet handle.
  }
}

// Finish checking fields.
ActOnFields(nullptr, Instantiation->getLocation(), Instantiation, Fields,
            SourceLocation(), SourceLocation(), ParsedAttributesView());
CheckCompletedCXXClass(nullptr, Instantiation);

// Default arguments are parsed, if not instantiated. We can go instantiate
// default arg exprs for default constructors if necessary now. Unless we're
// parsing a class, in which case wait until that's finished.
if (ParsingClassDepth == 0)
  ActOnFinishCXXNonNestedClass();

// Instantiate late parsed attributes, and attach them to their decls.
// See Sema::InstantiateAttrs
for (LateInstantiatedAttrVec::iterator I = LateAttrs.begin(),
     E = LateAttrs.end(); I != E; ++I) {
  assert(CurrentInstantiationScope == Instantiator.getStartingScope())(static_cast <bool> (CurrentInstantiationScope == Instantiator
.getStartingScope()) ? void (0) : __assert_fail ("CurrentInstantiationScope == Instantiator.getStartingScope()"
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2784, __extension__
 __PRETTY_FUNCTION__));
  CurrentInstantiationScope = I->Scope;

  // Allow 'this' within late-parsed attributes.
  auto *ND = cast<NamedDecl>(I->NewDecl);
  auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext());
  CXXThisScopeRAII ThisScope(*this, ThisContext, Qualifiers(),
                             ND->isCXXInstanceMember());

  Attr *NewAttr =
    instantiateTemplateAttribute(I->TmplAttr, Context, *this, TemplateArgs);
  if (NewAttr)
    I->NewDecl->addAttr(NewAttr);
  LocalInstantiationScope::deleteScopes(I->Scope,
                                        Instantiator.getStartingScope());
}
Instantiator.disableLateAttributeInstantiation();
LateAttrs.clear();

ActOnFinishDelayedMemberInitializers(Instantiation);

// FIXME: We should do something similar for explicit instantiations so they
// end up in the right module.
if (TSK == TSK_ImplicitInstantiation) {
  Instantiation->setLocation(Pattern->getLocation());
  Instantiation->setLocStart(Pattern->getInnerLocStart());
  Instantiation->setBraceRange(Pattern->getBraceRange());
}

if (!Instantiation->isInvalidDecl()) {
  // Perform any dependent diagnostics from the pattern.
  if (Pattern->isDependentContext())
    PerformDependentDiagnostics(Pattern, TemplateArgs);

  // Instantiate any out-of-line class template partial
  // specializations now.
  for (TemplateDeclInstantiator::delayed_partial_spec_iterator
            P = Instantiator.delayed_partial_spec_begin(),
         PEnd = Instantiator.delayed_partial_spec_end();
       P != PEnd; ++P) {
    if (!Instantiator.InstantiateClassTemplatePartialSpecialization(
            P->first, P->second)) {
      Instantiation->setInvalidDecl();
      break;
    }
  }

  // Instantiate any out-of-line variable template partial
  // specializations now.
  for (TemplateDeclInstantiator::delayed_var_partial_spec_iterator
            P = Instantiator.delayed_var_partial_spec_begin(),
         PEnd = Instantiator.delayed_var_partial_spec_end();
       P != PEnd; ++P) {
    if (!Instantiator.InstantiateVarTemplatePartialSpecialization(
            P->first, P->second)) {
      Instantiation->setInvalidDecl();
      break;
    }
  }
}

// Exit the scope of this instantiation.
SavedContext.pop();

if (!Instantiation->isInvalidDecl()) {
  // Always emit the vtable for an explicit instantiation definition
  // of a polymorphic class template specialization. Otherwise, eagerly
  // instantiate only constexpr virtual functions in preparation for their use
  // in constant evaluation.
  if (TSK == TSK_ExplicitInstantiationDefinition)
    MarkVTableUsed(PointOfInstantiation, Instantiation, true);
  else if (MightHaveConstexprVirtualFunctions)
    MarkVirtualMembersReferenced(PointOfInstantiation, Instantiation,
                                 /*ConstexprOnly*/ true);
}

Consumer.HandleTagDeclDefinition(Instantiation);

return Instantiation->isInvalidDecl();
2863}

2865/// Instantiate the definition of an enum from a given pattern.
2866///
2867/// \param PointOfInstantiation The point of instantiation within the
2868///        source code.
2869/// \param Instantiation is the declaration whose definition is being
2870///        instantiated. This will be a member enumeration of a class
2871///        temploid specialization, or a local enumeration within a
2872///        function temploid specialization.
2873/// \param Pattern The templated declaration from which the instantiation
2874///        occurs.
2875/// \param TemplateArgs The template arguments to be substituted into
2876///        the pattern.
2877/// \param TSK The kind of implicit or explicit instantiation to perform.
2878///
2879/// \return \c true if an error occurred, \c false otherwise.
2880bool Sema::InstantiateEnum(SourceLocation PointOfInstantiation,
                         EnumDecl *Instantiation, EnumDecl *Pattern,
                         const MultiLevelTemplateArgumentList &TemplateArgs,
                         TemplateSpecializationKind TSK) {
EnumDecl *PatternDef = Pattern->getDefinition();
if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Instantiation,
                               Instantiation->getInstantiatedFromMemberEnum(),
                                   Pattern, PatternDef, TSK,/*Complain*/true))
  return true;
Pattern = PatternDef;

// Record the point of instantiation.
if (MemberSpecializationInfo *MSInfo
      = Instantiation->getMemberSpecializationInfo()) {
  MSInfo->setTemplateSpecializationKind(TSK);
  MSInfo->setPointOfInstantiation(PointOfInstantiation);
}

InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
if (Inst.isInvalid())
  return true;
if (Inst.isAlreadyInstantiating())
  return false;
PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(),
                                    "instantiating enum definition");

// The instantiation is visible here, even if it was first declared in an
// unimported module.
Instantiation->setVisibleDespiteOwningModule();

// Enter the scope of this instantiation. We don't use
// PushDeclContext because we don't have a scope.
ContextRAII SavedContext(*this, Instantiation);
EnterExpressionEvaluationContext EvalContext(
    *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);

LocalInstantiationScope Scope(*this, /*MergeWithParentScope*/true);

// Pull attributes from the pattern onto the instantiation.
InstantiateAttrs(TemplateArgs, Pattern, Instantiation);

TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs);
Instantiator.InstantiateEnumDefinition(Instantiation, Pattern);

// Exit the scope of this instantiation.
SavedContext.pop();

return Instantiation->isInvalidDecl();
2928}


2931/// Instantiate the definition of a field from the given pattern.
2932///
2933/// \param PointOfInstantiation The point of instantiation within the
2934///        source code.
2935/// \param Instantiation is the declaration whose definition is being
2936///        instantiated. This will be a class of a class temploid
2937///        specialization, or a local enumeration within a function temploid
2938///        specialization.
2939/// \param Pattern The templated declaration from which the instantiation
2940///        occurs.
2941/// \param TemplateArgs The template arguments to be substituted into
2942///        the pattern.
2943///
2944/// \return \c true if an error occurred, \c false otherwise.
2945bool Sema::InstantiateInClassInitializer(
  SourceLocation PointOfInstantiation, FieldDecl *Instantiation,
  FieldDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs) {
// If there is no initializer, we don't need to do anything.
if (!Pattern->hasInClassInitializer())
  return false;

assert(Instantiation->getInClassInitStyle() ==(static_cast <bool> (Instantiation->getInClassInitStyle
() == Pattern->getInClassInitStyle() && "pattern and instantiation disagree about init style"
) ? void (0) : __assert_fail ("Instantiation->getInClassInitStyle() == Pattern->getInClassInitStyle() && \"pattern and instantiation disagree about init style\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2954, __extension__
 __PRETTY_FUNCTION__))
           Pattern->getInClassInitStyle() &&(static_cast <bool> (Instantiation->getInClassInitStyle
() == Pattern->getInClassInitStyle() && "pattern and instantiation disagree about init style"
) ? void (0) : __assert_fail ("Instantiation->getInClassInitStyle() == Pattern->getInClassInitStyle() && \"pattern and instantiation disagree about init style\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2954, __extension__
 __PRETTY_FUNCTION__))
       "pattern and instantiation disagree about init style")(static_cast <bool> (Instantiation->getInClassInitStyle
() == Pattern->getInClassInitStyle() && "pattern and instantiation disagree about init style"
) ? void (0) : __assert_fail ("Instantiation->getInClassInitStyle() == Pattern->getInClassInitStyle() && \"pattern and instantiation disagree about init style\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2954, __extension__
 __PRETTY_FUNCTION__));

// Error out if we haven't parsed the initializer of the pattern yet because
// we are waiting for the closing brace of the outer class.
Expr *OldInit = Pattern->getInClassInitializer();
if (!OldInit) {
  RecordDecl *PatternRD = Pattern->getParent();
  RecordDecl *OutermostClass = PatternRD->getOuterLexicalRecordContext();
  Diag(PointOfInstantiation,
       diag::err_default_member_initializer_not_yet_parsed)
      << OutermostClass << Pattern;
  Diag(Pattern->getEndLoc(),
       diag::note_default_member_initializer_not_yet_parsed);
  Instantiation->setInvalidDecl();
  return true;
}

InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);
if (Inst.isInvalid())
  return true;
if (Inst.isAlreadyInstantiating()) {
  // Error out if we hit an instantiation cycle for this initializer.
  Diag(PointOfInstantiation, diag::err_default_member_initializer_cycle)
    << Instantiation;
  return true;
}
PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(),
                                    "instantiating default member init");

// Enter the scope of this instantiation. We don't use PushDeclContext because
// we don't have a scope.
ContextRAII SavedContext(*this, Instantiation->getParent());
EnterExpressionEvaluationContext EvalContext(
    *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);

LocalInstantiationScope Scope(*this, true);

// Instantiate the initializer.
ActOnStartCXXInClassMemberInitializer();
CXXThisScopeRAII ThisScope(*this, Instantiation->getParent(), Qualifiers());

ExprResult NewInit = SubstInitializer(OldInit, TemplateArgs,
                                      /*CXXDirectInit=*/false);
Expr *Init = NewInit.get();
assert((!Init || !isa<ParenListExpr>(Init)) && "call-style init in class")(static_cast <bool> ((!Init || !isa<ParenListExpr>
(Init)) && "call-style init in class") ? void (0) : __assert_fail
 ("(!Init || !isa<ParenListExpr>(Init)) && \"call-style init in class\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 2998, __extension__
 __PRETTY_FUNCTION__));
ActOnFinishCXXInClassMemberInitializer(
    Instantiation, Init ? Init->getBeginLoc() : SourceLocation(), Init);

if (auto *L = getASTMutationListener())
  L->DefaultMemberInitializerInstantiated(Instantiation);

// Return true if the in-class initializer is still missing.
return !Instantiation->getInClassInitializer();
3007}

3009namespace {
/// A partial specialization whose template arguments have matched
/// a given template-id.
struct PartialSpecMatchResult {
  ClassTemplatePartialSpecializationDecl *Partial;
  TemplateArgumentList *Args;
};
3016}

3018bool Sema::usesPartialOrExplicitSpecialization(
  SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec) {
if (ClassTemplateSpec->getTemplateSpecializationKind() ==
    TSK_ExplicitSpecialization)
  return true;

SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
ClassTemplateSpec->getSpecializedTemplate()
                 ->getPartialSpecializations(PartialSpecs);
for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
  TemplateDeductionInfo Info(Loc);
  if (!DeduceTemplateArguments(PartialSpecs[I],
                               ClassTemplateSpec->getTemplateArgs(), Info))
    return true;
}

return false;
3035}

3037/// Get the instantiation pattern to use to instantiate the definition of a
3038/// given ClassTemplateSpecializationDecl (either the pattern of the primary
3039/// template or of a partial specialization).
3040static ActionResult<CXXRecordDecl *>
3041getPatternForClassTemplateSpecialization(
  Sema &S, SourceLocation PointOfInstantiation,
  ClassTemplateSpecializationDecl *ClassTemplateSpec,
  TemplateSpecializationKind TSK) {
Sema::InstantiatingTemplate Inst(S, PointOfInstantiation, ClassTemplateSpec);
if (Inst.isInvalid())
  return {/*Invalid=*/true};
if (Inst.isAlreadyInstantiating())
  return {/*Invalid=*/false};

llvm::PointerUnion<ClassTemplateDecl *,
                   ClassTemplatePartialSpecializationDecl *>
    Specialized = ClassTemplateSpec->getSpecializedTemplateOrPartial();
if (!Specialized.is<ClassTemplatePartialSpecializationDecl *>()) {
  // Find best matching specialization.
  ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();

  // C++ [temp.class.spec.match]p1:
  //   When a class template is used in a context that requires an
  //   instantiation of the class, it is necessary to determine
  //   whether the instantiation is to be generated using the primary
  //   template or one of the partial specializations. This is done by
  //   matching the template arguments of the class template
  //   specialization with the template argument lists of the partial
  //   specializations.
  typedef PartialSpecMatchResult MatchResult;
  SmallVector<MatchResult, 4> Matched;
  SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
  Template->getPartialSpecializations(PartialSpecs);
  TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation);
  for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
    ClassTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
    TemplateDeductionInfo Info(FailedCandidates.getLocation());
    if (Sema::TemplateDeductionResult Result = S.DeduceTemplateArguments(
            Partial, ClassTemplateSpec->getTemplateArgs(), Info)) {
      // Store the failed-deduction information for use in diagnostics, later.
      // TODO: Actually use the failed-deduction info?
      FailedCandidates.addCandidate().set(
          DeclAccessPair::make(Template, AS_public), Partial,
          MakeDeductionFailureInfo(S.Context, Result, Info));
      (void)Result;
    } else {
      Matched.push_back(PartialSpecMatchResult());
      Matched.back().Partial = Partial;
      Matched.back().Args = Info.take();
    }
  }

  // If we're dealing with a member template where the template parameters
  // have been instantiated, this provides the original template parameters
  // from which the member template's parameters were instantiated.

  if (Matched.size() >= 1) {
    SmallVectorImpl<MatchResult>::iterator Best = Matched.begin();
    if (Matched.size() == 1) {
      //   -- If exactly one matching specialization is found, the
      //      instantiation is generated from that specialization.
      // We don't need to do anything for this.
    } else {
      //   -- If more than one matching specialization is found, the
      //      partial order rules (14.5.4.2) are used to determine
      //      whether one of the specializations is more specialized
      //      than the others. If none of the specializations is more
      //      specialized than all of the other matching
      //      specializations, then the use of the class template is
      //      ambiguous and the program is ill-formed.
      for (SmallVectorImpl<MatchResult>::iterator P = Best + 1,
                                               PEnd = Matched.end();
           P != PEnd; ++P) {
        if (S.getMoreSpecializedPartialSpecialization(
                P->Partial, Best->Partial, PointOfInstantiation) ==
            P->Partial)
          Best = P;
      }

      // Determine if the best partial specialization is more specialized than
      // the others.
      bool Ambiguous = false;
      for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(),
                                               PEnd = Matched.end();
           P != PEnd; ++P) {
        if (P != Best && S.getMoreSpecializedPartialSpecialization(
                             P->Partial, Best->Partial,
                             PointOfInstantiation) != Best->Partial) {
          Ambiguous = true;
          break;
        }
      }

      if (Ambiguous) {
        // Partial ordering did not produce a clear winner. Complain.
        Inst.Clear();
        ClassTemplateSpec->setInvalidDecl();
        S.Diag(PointOfInstantiation,
               diag::err_partial_spec_ordering_ambiguous)
            << ClassTemplateSpec;

        // Print the matching partial specializations.
        for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(),
                                                 PEnd = Matched.end();
             P != PEnd; ++P)
          S.Diag(P->Partial->getLocation(), diag::note_partial_spec_match)
              << S.getTemplateArgumentBindingsText(
                     P->Partial->getTemplateParameters(), *P->Args);

        return {/*Invalid=*/true};
      }
    }

    ClassTemplateSpec->setInstantiationOf(Best->Partial, Best->Args);
  } else {
    //   -- If no matches are found, the instantiation is generated
    //      from the primary template.
  }
}

CXXRecordDecl *Pattern = nullptr;
Specialized = ClassTemplateSpec->getSpecializedTemplateOrPartial();
if (auto *PartialSpec =
        Specialized.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
  // Instantiate using the best class template partial specialization.
  while (PartialSpec->getInstantiatedFromMember()) {
    // If we've found an explicit specialization of this class template,
    // stop here and use that as the pattern.
    if (PartialSpec->isMemberSpecialization())
      break;

    PartialSpec = PartialSpec->getInstantiatedFromMember();
  }
  Pattern = PartialSpec;
} else {
  ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
  while (Template->getInstantiatedFromMemberTemplate()) {
    // If we've found an explicit specialization of this class template,
    // stop here and use that as the pattern.
    if (Template->isMemberSpecialization())
      break;

    Template = Template->getInstantiatedFromMemberTemplate();
  }
  Pattern = Template->getTemplatedDecl();
}

return Pattern;
3185}

3187bool Sema::InstantiateClassTemplateSpecialization(
  SourceLocation PointOfInstantiation,
  ClassTemplateSpecializationDecl *ClassTemplateSpec,
  TemplateSpecializationKind TSK, bool Complain) {
// Perform the actual instantiation on the canonical declaration.
ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(
    ClassTemplateSpec->getCanonicalDecl());
if (ClassTemplateSpec->isInvalidDecl())
  return true;

ActionResult<CXXRecordDecl *> Pattern =
    getPatternForClassTemplateSpecialization(*this, PointOfInstantiation,
                                             ClassTemplateSpec, TSK);
if (!Pattern.isUsable())
  return Pattern.isInvalid();

return InstantiateClass(
    PointOfInstantiation, ClassTemplateSpec, Pattern.get(),
    getTemplateInstantiationArgs(ClassTemplateSpec), TSK, Complain);
3206}

3208/// Instantiates the definitions of all of the member
3209/// of the given class, which is an instantiation of a class template
3210/// or a member class of a template.
3211void
3212Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation,
                            CXXRecordDecl *Instantiation,
                      const MultiLevelTemplateArgumentList &TemplateArgs,
                            TemplateSpecializationKind TSK) {
// FIXME: We need to notify the ASTMutationListener that we did all of these
// things, in case we have an explicit instantiation definition in a PCM, a
// module, or preamble, and the declaration is in an imported AST.
assert((static_cast <bool> ((TSK == TSK_ExplicitInstantiationDefinition
 || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation
 && Instantiation->isLocalClass())) && "Unexpected template specialization kind!"
) ? void (0) : __assert_fail ("(TSK == TSK_ExplicitInstantiationDefinition || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) && \"Unexpected template specialization kind!\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3223, __extension__
 __PRETTY_FUNCTION__))
    (TSK == TSK_ExplicitInstantiationDefinition ||(static_cast <bool> ((TSK == TSK_ExplicitInstantiationDefinition
 || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation
 && Instantiation->isLocalClass())) && "Unexpected template specialization kind!"
) ? void (0) : __assert_fail ("(TSK == TSK_ExplicitInstantiationDefinition || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) && \"Unexpected template specialization kind!\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3223, __extension__
 __PRETTY_FUNCTION__))
     TSK == TSK_ExplicitInstantiationDeclaration ||(static_cast <bool> ((TSK == TSK_ExplicitInstantiationDefinition
 || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation
 && Instantiation->isLocalClass())) && "Unexpected template specialization kind!"
) ? void (0) : __assert_fail ("(TSK == TSK_ExplicitInstantiationDefinition || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) && \"Unexpected template specialization kind!\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3223, __extension__
 __PRETTY_FUNCTION__))
     (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) &&(static_cast <bool> ((TSK == TSK_ExplicitInstantiationDefinition
 || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation
 && Instantiation->isLocalClass())) && "Unexpected template specialization kind!"
) ? void (0) : __assert_fail ("(TSK == TSK_ExplicitInstantiationDefinition || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) && \"Unexpected template specialization kind!\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3223, __extension__
 __PRETTY_FUNCTION__))
    "Unexpected template specialization kind!")(static_cast <bool> ((TSK == TSK_ExplicitInstantiationDefinition
 || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation
 && Instantiation->isLocalClass())) && "Unexpected template specialization kind!"
) ? void (0) : __assert_fail ("(TSK == TSK_ExplicitInstantiationDefinition || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) && \"Unexpected template specialization kind!\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3223, __extension__
 __PRETTY_FUNCTION__));
for (auto *D : Instantiation->decls()) {
  bool SuppressNew = false;
  if (auto *Function = dyn_cast<FunctionDecl>(D)) {
    if (FunctionDecl *Pattern =
            Function->getInstantiatedFromMemberFunction()) {

      if (Function->getTrailingRequiresClause()) {
        ConstraintSatisfaction Satisfaction;
        if (CheckFunctionConstraints(Function, Satisfaction) ||
            !Satisfaction.IsSatisfied) {
          continue;
        }
      }

      if (Function->hasAttr<ExcludeFromExplicitInstantiationAttr>())
        continue;

      MemberSpecializationInfo *MSInfo =
          Function->getMemberSpecializationInfo();
      assert(MSInfo && "No member specialization information?")(static_cast <bool> (MSInfo && "No member specialization information?"
) ? void (0) : __assert_fail ("MSInfo && \"No member specialization information?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3243, __extension__
 __PRETTY_FUNCTION__));
      if (MSInfo->getTemplateSpecializationKind()
                                               == TSK_ExplicitSpecialization)
        continue;

      if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
                                                 Function,
                                      MSInfo->getTemplateSpecializationKind(),
                                            MSInfo->getPointOfInstantiation(),
                                                 SuppressNew) ||
          SuppressNew)
        continue;

      // C++11 [temp.explicit]p8:
      //   An explicit instantiation definition that names a class template
      //   specialization explicitly instantiates the class template
      //   specialization and is only an explicit instantiation definition
      //   of members whose definition is visible at the point of
      //   instantiation.
      if (TSK == TSK_ExplicitInstantiationDefinition && !Pattern->isDefined())
        continue;

      Function->setTemplateSpecializationKind(TSK, PointOfInstantiation);

      if (Function->isDefined()) {
        // Let the ASTConsumer know that this function has been explicitly
        // instantiated now, and its linkage might have changed.
        Consumer.HandleTopLevelDecl(DeclGroupRef(Function));
      } else if (TSK == TSK_ExplicitInstantiationDefinition) {
        InstantiateFunctionDefinition(PointOfInstantiation, Function);
      } else if (TSK == TSK_ImplicitInstantiation) {
        PendingLocalImplicitInstantiations.push_back(
            std::make_pair(Function, PointOfInstantiation));
      }
    }
  } else if (auto *Var = dyn_cast<VarDecl>(D)) {
    if (isa<VarTemplateSpecializationDecl>(Var))
      continue;

    if (Var->isStaticDataMember()) {
      if (Var->hasAttr<ExcludeFromExplicitInstantiationAttr>())
        continue;

      MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo();
      assert(MSInfo && "No member specialization information?")(static_cast <bool> (MSInfo && "No member specialization information?"
) ? void (0) : __assert_fail ("MSInfo && \"No member specialization information?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3287, __extension__
 __PRETTY_FUNCTION__));
      if (MSInfo->getTemplateSpecializationKind()
                                               == TSK_ExplicitSpecialization)
        continue;

      if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
                                                 Var,
                                      MSInfo->getTemplateSpecializationKind(),
                                            MSInfo->getPointOfInstantiation(),
                                                 SuppressNew) ||
          SuppressNew)
        continue;

      if (TSK == TSK_ExplicitInstantiationDefinition) {
        // C++0x [temp.explicit]p8:
        //   An explicit instantiation definition that names a class template
        //   specialization explicitly instantiates the class template
        //   specialization and is only an explicit instantiation definition
        //   of members whose definition is visible at the point of
        //   instantiation.
        if (!Var->getInstantiatedFromStaticDataMember()->getDefinition())
          continue;

        Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
        InstantiateVariableDefinition(PointOfInstantiation, Var);
      } else {
        Var->setTemplateSpecializationKind(TSK, PointOfInstantiation);
      }
    }
  } else if (auto *Record = dyn_cast<CXXRecordDecl>(D)) {
    if (Record->hasAttr<ExcludeFromExplicitInstantiationAttr>())
      continue;

    // Always skip the injected-class-name, along with any
    // redeclarations of nested classes, since both would cause us
    // to try to instantiate the members of a class twice.
    // Skip closure types; they'll get instantiated when we instantiate
    // the corresponding lambda-expression.
    if (Record->isInjectedClassName() || Record->getPreviousDecl() ||
        Record->isLambda())
      continue;

    MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo();
    assert(MSInfo && "No member specialization information?")(static_cast <bool> (MSInfo && "No member specialization information?"
) ? void (0) : __assert_fail ("MSInfo && \"No member specialization information?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3330, __extension__
 __PRETTY_FUNCTION__));

    if (MSInfo->getTemplateSpecializationKind()
                                              == TSK_ExplicitSpecialization)
      continue;

    if (Context.getTargetInfo().getTriple().isOSWindows() &&
        TSK == TSK_ExplicitInstantiationDeclaration) {
      // On Windows, explicit instantiation decl of the outer class doesn't
      // affect the inner class. Typically extern template declarations are
      // used in combination with dll import/export annotations, but those
      // are not propagated from the outer class templates to inner classes.
      // Therefore, do not instantiate inner classes on this platform, so
      // that users don't end up with undefined symbols during linking.
      continue;
    }

    if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK,
                                               Record,
                                      MSInfo->getTemplateSpecializationKind(),
                                            MSInfo->getPointOfInstantiation(),
                                               SuppressNew) ||
        SuppressNew)
      continue;

    CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
    assert(Pattern && "Missing instantiated-from-template information")(static_cast <bool> (Pattern && "Missing instantiated-from-template information"
) ? void (0) : __assert_fail ("Pattern && \"Missing instantiated-from-template information\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3356, __extension__
 __PRETTY_FUNCTION__));

    if (!Record->getDefinition()) {
      if (!Pattern->getDefinition()) {
        // C++0x [temp.explicit]p8:
        //   An explicit instantiation definition that names a class template
        //   specialization explicitly instantiates the class template
        //   specialization and is only an explicit instantiation definition
        //   of members whose definition is visible at the point of
        //   instantiation.
        if (TSK == TSK_ExplicitInstantiationDeclaration) {
          MSInfo->setTemplateSpecializationKind(TSK);
          MSInfo->setPointOfInstantiation(PointOfInstantiation);
        }

        continue;
      }

      InstantiateClass(PointOfInstantiation, Record, Pattern,
                       TemplateArgs,
                       TSK);
    } else {
      if (TSK == TSK_ExplicitInstantiationDefinition &&
          Record->getTemplateSpecializationKind() ==
              TSK_ExplicitInstantiationDeclaration) {
        Record->setTemplateSpecializationKind(TSK);
        MarkVTableUsed(PointOfInstantiation, Record, true);
      }
    }

    Pattern = cast_or_null<CXXRecordDecl>(Record->getDefinition());
    if (Pattern)
      InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs,
                              TSK);
  } else if (auto *Enum = dyn_cast<EnumDecl>(D)) {
    MemberSpecializationInfo *MSInfo = Enum->getMemberSpecializationInfo();
    assert(MSInfo && "No member specialization information?")(static_cast <bool> (MSInfo && "No member specialization information?"
) ? void (0) : __assert_fail ("MSInfo && \"No member specialization information?\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3392, __extension__
 __PRETTY_FUNCTION__));

    if (MSInfo->getTemplateSpecializationKind()
          == TSK_ExplicitSpecialization)
      continue;

    if (CheckSpecializationInstantiationRedecl(
          PointOfInstantiation, TSK, Enum,
          MSInfo->getTemplateSpecializationKind(),
          MSInfo->getPointOfInstantiation(), SuppressNew) ||
        SuppressNew)
      continue;

    if (Enum->getDefinition())
      continue;

    EnumDecl *Pattern = Enum->getTemplateInstantiationPattern();
    assert(Pattern && "Missing instantiated-from-template information")(static_cast <bool> (Pattern && "Missing instantiated-from-template information"
) ? void (0) : __assert_fail ("Pattern && \"Missing instantiated-from-template information\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3409, __extension__
 __PRETTY_FUNCTION__));

    if (TSK == TSK_ExplicitInstantiationDefinition) {
      if (!Pattern->getDefinition())
        continue;

      InstantiateEnum(PointOfInstantiation, Enum, Pattern, TemplateArgs, TSK);
    } else {
      MSInfo->setTemplateSpecializationKind(TSK);
      MSInfo->setPointOfInstantiation(PointOfInstantiation);
    }
  } else if (auto *Field = dyn_cast<FieldDecl>(D)) {
    // No need to instantiate in-class initializers during explicit
    // instantiation.
    if (Field->hasInClassInitializer() && TSK == TSK_ImplicitInstantiation) {
      CXXRecordDecl *ClassPattern =
          Instantiation->getTemplateInstantiationPattern();
      DeclContext::lookup_result Lookup =
          ClassPattern->lookup(Field->getDeclName());
      FieldDecl *Pattern = Lookup.find_first<FieldDecl>();
      assert(Pattern)(static_cast <bool> (Pattern) ? void (0) : __assert_fail
 ("Pattern", "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3429
, __extension__ __PRETTY_FUNCTION__));
      InstantiateInClassInitializer(PointOfInstantiation, Field, Pattern,
                                    TemplateArgs);
    }
  }
}
3435}

3437/// Instantiate the definitions of all of the members of the
3438/// given class template specialization, which was named as part of an
3439/// explicit instantiation.
3440void
3441Sema::InstantiateClassTemplateSpecializationMembers(
                                         SourceLocation PointOfInstantiation,
                          ClassTemplateSpecializationDecl *ClassTemplateSpec,
                                             TemplateSpecializationKind TSK) {
// C++0x [temp.explicit]p7:
//   An explicit instantiation that names a class template
//   specialization is an explicit instantion of the same kind
//   (declaration or definition) of each of its members (not
//   including members inherited from base classes) that has not
//   been previously explicitly specialized in the translation unit
//   containing the explicit instantiation, except as described
//   below.
InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec,
                        getTemplateInstantiationArgs(ClassTemplateSpec),
                        TSK);
3456}

3458StmtResult
3459Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) {
if (!S)
  return S;

TemplateInstantiator Instantiator(*this, TemplateArgs,
                                  SourceLocation(),
                                  DeclarationName());
return Instantiator.TransformStmt(S);
3467}

3469bool Sema::SubstTemplateArguments(
  ArrayRef<TemplateArgumentLoc> Args,
  const MultiLevelTemplateArgumentList &TemplateArgs,
  TemplateArgumentListInfo &Out) {
TemplateInstantiator Instantiator(*this, TemplateArgs,
                                  SourceLocation(),
                                  DeclarationName());
return Instantiator.TransformTemplateArguments(Args.begin(), Args.end(),
                                               Out);
3478}

3480ExprResult
3481Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) {
if (!E)
  return E;

TemplateInstantiator Instantiator(*this, TemplateArgs,
                                  SourceLocation(),
                                  DeclarationName());
return Instantiator.TransformExpr(E);
3489}

3491ExprResult Sema::SubstInitializer(Expr *Init,
                        const MultiLevelTemplateArgumentList &TemplateArgs,
                        bool CXXDirectInit) {
TemplateInstantiator Instantiator(*this, TemplateArgs,
                                  SourceLocation(),
                                  DeclarationName());
return Instantiator.TransformInitializer(Init, CXXDirectInit);
3498}

3500bool Sema::SubstExprs(ArrayRef<Expr *> Exprs, bool IsCall,
                    const MultiLevelTemplateArgumentList &TemplateArgs,
                    SmallVectorImpl<Expr *> &Outputs) {
if (Exprs.empty())
  return false;

TemplateInstantiator Instantiator(*this, TemplateArgs,
                                  SourceLocation(),
                                  DeclarationName());
return Instantiator.TransformExprs(Exprs.data(), Exprs.size(),
                                   IsCall, Outputs);
3511}

3513NestedNameSpecifierLoc
3514Sema::SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS,
                      const MultiLevelTemplateArgumentList &TemplateArgs) {
if (!NNS)
  return NestedNameSpecifierLoc();

TemplateInstantiator Instantiator(*this, TemplateArgs, NNS.getBeginLoc(),
                                  DeclarationName());
return Instantiator.TransformNestedNameSpecifierLoc(NNS);
3522}

3524/// Do template substitution on declaration name info.
3525DeclarationNameInfo
3526Sema::SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
                       const MultiLevelTemplateArgumentList &TemplateArgs) {
TemplateInstantiator Instantiator(*this, TemplateArgs, NameInfo.getLoc(),
                                  NameInfo.getName());
return Instantiator.TransformDeclarationNameInfo(NameInfo);
3531}

3533TemplateName
3534Sema::SubstTemplateName(NestedNameSpecifierLoc QualifierLoc,
                      TemplateName Name, SourceLocation Loc,
                      const MultiLevelTemplateArgumentList &TemplateArgs) {
TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
                                  DeclarationName());
CXXScopeSpec SS;
SS.Adopt(QualifierLoc);
return Instantiator.TransformTemplateName(SS, Name, Loc);
3542}

3544static const Decl *getCanonicalParmVarDecl(const Decl *D) {
// When storing ParmVarDecls in the local instantiation scope, we always
// want to use the ParmVarDecl from the canonical function declaration,
// since the map is then valid for any redeclaration or definition of that
// function.
if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(D)) {
  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) {
    unsigned i = PV->getFunctionScopeIndex();
    // This parameter might be from a freestanding function type within the
    // function and isn't necessarily referring to one of FD's parameters.
    if (i < FD->getNumParams() && FD->getParamDecl(i) == PV)
      return FD->getCanonicalDecl()->getParamDecl(i);
  }
}
return D;
3559}


3562llvm::PointerUnion<Decl *, LocalInstantiationScope::DeclArgumentPack *> *
3563LocalInstantiationScope::findInstantiationOf(const Decl *D) {
D = getCanonicalParmVarDecl(D);
for (LocalInstantiationScope *Current = this; Current;
     Current = Current->Outer) {

  // Check if we found something within this scope.
  const Decl *CheckD = D;
  do {
    LocalDeclsMap::iterator Found = Current->LocalDecls.find(CheckD);
    if (Found != Current->LocalDecls.end())
      return &Found->second;

    // If this is a tag declaration, it's possible that we need to look for
    // a previous declaration.
    if (const TagDecl *Tag = dyn_cast<TagDecl>(CheckD))
      CheckD = Tag->getPreviousDecl();
    else
      CheckD = nullptr;
  } while (CheckD);

  // If we aren't combined with our outer scope, we're done.
  if (!Current->CombineWithOuterScope)
    break;
}

// If we're performing a partial substitution during template argument
// deduction, we may not have values for template parameters yet.
if (isa<NonTypeTemplateParmDecl>(D) || isa<TemplateTypeParmDecl>(D) ||
    isa<TemplateTemplateParmDecl>(D))
  return nullptr;

// Local types referenced prior to definition may require instantiation.
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D))
  if (RD->isLocalClass())
    return nullptr;

// Enumeration types referenced prior to definition may appear as a result of
// error recovery.
if (isa<EnumDecl>(D))
  return nullptr;

// Materialized typedefs/type alias for implicit deduction guides may require
// instantiation.
if (isa<TypedefNameDecl>(D) &&
    isa<CXXDeductionGuideDecl>(D->getDeclContext()))
  return nullptr;

// If we didn't find the decl, then we either have a sema bug, or we have a
// forward reference to a label declaration.  Return null to indicate that
// we have an uninstantiated label.
assert(isa<LabelDecl>(D) && "declaration not instantiated in this scope")(static_cast <bool> (isa<LabelDecl>(D) &&
 "declaration not instantiated in this scope") ? void (0) : __assert_fail
 ("isa<LabelDecl>(D) && \"declaration not instantiated in this scope\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3613, __extension__
 __PRETTY_FUNCTION__));
return nullptr;
3615}

3617void LocalInstantiationScope::InstantiatedLocal(const Decl *D, Decl *Inst) {
D = getCanonicalParmVarDecl(D);
llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D];
if (Stored.isNull()) {
3621#ifndef NDEBUG
  // It should not be present in any surrounding scope either.
  LocalInstantiationScope *Current = this;
  while (Current->CombineWithOuterScope && Current->Outer) {
    Current = Current->Outer;
    assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() &&(static_cast <bool> (Current->LocalDecls.find(D) == Current
->LocalDecls.end() && "Instantiated local in inner and outer scopes"
) ? void (0) : __assert_fail ("Current->LocalDecls.find(D) == Current->LocalDecls.end() && \"Instantiated local in inner and outer scopes\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3627, __extension__
 __PRETTY_FUNCTION__))
           "Instantiated local in inner and outer scopes")(static_cast <bool> (Current->LocalDecls.find(D) == Current
->LocalDecls.end() && "Instantiated local in inner and outer scopes"
) ? void (0) : __assert_fail ("Current->LocalDecls.find(D) == Current->LocalDecls.end() && \"Instantiated local in inner and outer scopes\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3627, __extension__
 __PRETTY_FUNCTION__));
  }
3629#endif
  Stored = Inst;
} else if (DeclArgumentPack *Pack = Stored.dyn_cast<DeclArgumentPack *>()) {
  Pack->push_back(cast<VarDecl>(Inst));
} else {
  assert(Stored.get<Decl *>() == Inst && "Already instantiated this local")(static_cast <bool> (Stored.get<Decl *>() == Inst
 && "Already instantiated this local") ? void (0) : __assert_fail
 ("Stored.get<Decl *>() == Inst && \"Already instantiated this local\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3634, __extension__
 __PRETTY_FUNCTION__));
}
3636}

3638void LocalInstantiationScope::InstantiatedLocalPackArg(const Decl *D,
                                                     VarDecl *Inst) {
D = getCanonicalParmVarDecl(D);
DeclArgumentPack *Pack = LocalDecls[D].get<DeclArgumentPack *>();
Pack->push_back(Inst);
3643}

3645void LocalInstantiationScope::MakeInstantiatedLocalArgPack(const Decl *D) {
3646#ifndef NDEBUG
// This should be the first time we've been told about this decl.
for (LocalInstantiationScope *Current = this;
     Current && Current->CombineWithOuterScope; Current = Current->Outer)
  assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() &&(static_cast <bool> (Current->LocalDecls.find(D) == Current
->LocalDecls.end() && "Creating local pack after instantiation of local"
) ? void (0) : __assert_fail ("Current->LocalDecls.find(D) == Current->LocalDecls.end() && \"Creating local pack after instantiation of local\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3651, __extension__
 __PRETTY_FUNCTION__))
         "Creating local pack after instantiation of local")(static_cast <bool> (Current->LocalDecls.find(D) == Current
->LocalDecls.end() && "Creating local pack after instantiation of local"
) ? void (0) : __assert_fail ("Current->LocalDecls.find(D) == Current->LocalDecls.end() && \"Creating local pack after instantiation of local\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3651, __extension__
 __PRETTY_FUNCTION__));
3652#endif

D = getCanonicalParmVarDecl(D);
llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D];
DeclArgumentPack *Pack = new DeclArgumentPack;
Stored = Pack;
ArgumentPacks.push_back(Pack);
3659}

3661bool LocalInstantiationScope::isLocalPackExpansion(const Decl *D) {
for (DeclArgumentPack *Pack : ArgumentPacks)
  if (llvm::is_contained(*Pack, D))
    return true;
return false;
3666}

3668void LocalInstantiationScope::SetPartiallySubstitutedPack(NamedDecl *Pack,
                                        const TemplateArgument *ExplicitArgs,
                                                  unsigned NumExplicitArgs) {
assert((!PartiallySubstitutedPack || PartiallySubstitutedPack == Pack) &&(static_cast <bool> ((!PartiallySubstitutedPack || PartiallySubstitutedPack
 == Pack) && "Already have a partially-substituted pack"
) ? void (0) : __assert_fail ("(!PartiallySubstitutedPack || PartiallySubstitutedPack == Pack) && \"Already have a partially-substituted pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3672, __extension__
 __PRETTY_FUNCTION__))
       "Already have a partially-substituted pack")(static_cast <bool> ((!PartiallySubstitutedPack || PartiallySubstitutedPack
 == Pack) && "Already have a partially-substituted pack"
) ? void (0) : __assert_fail ("(!PartiallySubstitutedPack || PartiallySubstitutedPack == Pack) && \"Already have a partially-substituted pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3672, __extension__
 __PRETTY_FUNCTION__));
assert((!PartiallySubstitutedPack(static_cast <bool> ((!PartiallySubstitutedPack || NumArgsInPartiallySubstitutedPack
 == NumExplicitArgs) && "Wrong number of arguments in partially-substituted pack"
) ? void (0) : __assert_fail ("(!PartiallySubstitutedPack || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) && \"Wrong number of arguments in partially-substituted pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3675, __extension__
 __PRETTY_FUNCTION__))
        || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) &&(static_cast <bool> ((!PartiallySubstitutedPack || NumArgsInPartiallySubstitutedPack
 == NumExplicitArgs) && "Wrong number of arguments in partially-substituted pack"
) ? void (0) : __assert_fail ("(!PartiallySubstitutedPack || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) && \"Wrong number of arguments in partially-substituted pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3675, __extension__
 __PRETTY_FUNCTION__))
       "Wrong number of arguments in partially-substituted pack")(static_cast <bool> ((!PartiallySubstitutedPack || NumArgsInPartiallySubstitutedPack
 == NumExplicitArgs) && "Wrong number of arguments in partially-substituted pack"
) ? void (0) : __assert_fail ("(!PartiallySubstitutedPack || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) && \"Wrong number of arguments in partially-substituted pack\""
, "clang/lib/Sema/SemaTemplateInstantiate.cpp", 3675, __extension__
 __PRETTY_FUNCTION__));
PartiallySubstitutedPack = Pack;
ArgsInPartiallySubstitutedPack = ExplicitArgs;
NumArgsInPartiallySubstitutedPack = NumExplicitArgs;
3679}

3681NamedDecl *LocalInstantiationScope::getPartiallySubstitutedPack(
                                       const TemplateArgument **ExplicitArgs,
                                            unsigned *NumExplicitArgs) const {
if (ExplicitArgs)
  *ExplicitArgs = nullptr;
if (NumExplicitArgs)
  *NumExplicitArgs = 0;

for (const LocalInstantiationScope *Current = this; Current;
     Current = Current->Outer) {
  if (Current->PartiallySubstitutedPack) {
    if (ExplicitArgs)
      *ExplicitArgs = Current->ArgsInPartiallySubstitutedPack;
    if (NumExplicitArgs)
      *NumExplicitArgs = Current->NumArgsInPartiallySubstitutedPack;

    return Current->PartiallySubstitutedPack;
  }

  if (!Current->CombineWithOuterScope)
    break;
}

return nullptr;
3705}