/build/source/clang/include/clang/AST/ExprCXX.h

Bug Summary

File:	build/source/clang/include/clang/AST/ExprCXX.h
Warning:	line 4927, column 18 Called C++ object pointer is null

Annotated Source Code

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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 SemaCoroutine.cpp -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/source/build-llvm -resource-dir /usr/lib/llvm-17/lib/clang/17 -D _DEBUG -D _GLIBCXX_ASSERTIONS -D _GNU_SOURCE -D _LIBCPP_ENABLE_ASSERTIONS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/clang/lib/Sema -I /build/source/clang/lib/Sema -I /build/source/clang/include -I tools/clang/include -I include -I /build/source/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-17/lib/clang/17/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/source/build-llvm=build-llvm -fmacro-prefix-map=/build/source/= -fcoverage-prefix-map=/build/source/build-llvm=build-llvm -fcoverage-prefix-map=/build/source/= -source-date-epoch 1679915782 -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 -Wno-misleading-indentation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/source/build-llvm -fdebug-prefix-map=/build/source/build-llvm=build-llvm -fdebug-prefix-map=/build/source/= -fdebug-prefix-map=/build/source/build-llvm=build-llvm -fdebug-prefix-map=/build/source/= -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-2023-03-27-130437-16335-1 -x c++ /build/source/clang/lib/Sema/SemaCoroutine.cpp

/build/source/clang/lib/Sema/SemaCoroutine.cpp

→

1//===-- SemaCoroutine.cpp - Semantic Analysis for Coroutines --------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file implements semantic analysis for C++ Coroutines.
10//
11//  This file contains references to sections of the Coroutines TS, which
12//  can be found at http://wg21.link/coroutines.
13//
14//===----------------------------------------------------------------------===//

16#include "CoroutineStmtBuilder.h"
17#include "clang/AST/ASTLambda.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/AST/StmtCXX.h"
21#include "clang/Basic/Builtins.h"
22#include "clang/Lex/Preprocessor.h"
23#include "clang/Sema/Initialization.h"
24#include "clang/Sema/Overload.h"
25#include "clang/Sema/ScopeInfo.h"
26#include "clang/Sema/SemaInternal.h"
27#include "llvm/ADT/SmallSet.h"

29using namespace clang;
30using namespace sema;

32static LookupResult lookupMember(Sema &S, const char *Name, CXXRecordDecl *RD,
                               SourceLocation Loc, bool &Res) {
DeclarationName DN = S.PP.getIdentifierInfo(Name);
LookupResult LR(S, DN, Loc, Sema::LookupMemberName);
// Suppress diagnostics when a private member is selected. The same warnings
// will be produced again when building the call.
LR.suppressDiagnostics();
Res = S.LookupQualifiedName(LR, RD);
return LR;
41}

43static bool lookupMember(Sema &S, const char *Name, CXXRecordDecl *RD,
                       SourceLocation Loc) {
bool Res;
lookupMember(S, Name, RD, Loc, Res);
return Res;
48}

50/// Look up the std::coroutine_traits<...>::promise_type for the given
51/// function type.
52static QualType lookupPromiseType(Sema &S, const FunctionDecl *FD,
                                SourceLocation KwLoc) {
const FunctionProtoType *FnType = FD->getType()->castAs<FunctionProtoType>();
const SourceLocation FuncLoc = FD->getLocation();

ClassTemplateDecl *CoroTraits =
    S.lookupCoroutineTraits(KwLoc, FuncLoc);
if (!CoroTraits)
  return QualType();

// Form template argument list for coroutine_traits<R, P1, P2, ...> according
// to [dcl.fct.def.coroutine]3
TemplateArgumentListInfo Args(KwLoc, KwLoc);
auto AddArg = [&](QualType T) {
  Args.addArgument(TemplateArgumentLoc(
      TemplateArgument(T), S.Context.getTrivialTypeSourceInfo(T, KwLoc)));
};
AddArg(FnType->getReturnType());
// If the function is a non-static member function, add the type
// of the implicit object parameter before the formal parameters.
if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
  if (MD->isInstance()) {
    // [over.match.funcs]4
    // For non-static member functions, the type of the implicit object
    // parameter is
    //  -- "lvalue reference to cv X" for functions declared without a
    //      ref-qualifier or with the & ref-qualifier
    //  -- "rvalue reference to cv X" for functions declared with the &&
    //      ref-qualifier
    QualType T = MD->getThisType()->castAs<PointerType>()->getPointeeType();
    T = FnType->getRefQualifier() == RQ_RValue
            ? S.Context.getRValueReferenceType(T)
            : S.Context.getLValueReferenceType(T, /*SpelledAsLValue*/ true);
    AddArg(T);
  }
}
for (QualType T : FnType->getParamTypes())
  AddArg(T);

// Build the template-id.
QualType CoroTrait =
    S.CheckTemplateIdType(TemplateName(CoroTraits), KwLoc, Args);
if (CoroTrait.isNull())
  return QualType();
if (S.RequireCompleteType(KwLoc, CoroTrait,
                          diag::err_coroutine_type_missing_specialization))
  return QualType();

auto *RD = CoroTrait->getAsCXXRecordDecl();
assert(RD && "specialization of class template is not a class?")(static_cast <bool> (RD && "specialization of class template is not a class?"
) ? void (0) : __assert_fail ("RD && \"specialization of class template is not a class?\""
, "clang/lib/Sema/SemaCoroutine.cpp", 101, __extension__ __PRETTY_FUNCTION__
));

// Look up the ::promise_type member.
LookupResult R(S, &S.PP.getIdentifierTable().get("promise_type"), KwLoc,
               Sema::LookupOrdinaryName);
S.LookupQualifiedName(R, RD);
auto *Promise = R.getAsSingle<TypeDecl>();
if (!Promise) {
  S.Diag(FuncLoc,
         diag::err_implied_std_coroutine_traits_promise_type_not_found)
      << RD;
  return QualType();
}
// The promise type is required to be a class type.
QualType PromiseType = S.Context.getTypeDeclType(Promise);

auto buildElaboratedType = [&]() {
  auto *NNS = NestedNameSpecifier::Create(S.Context, nullptr, S.getStdNamespace());
  NNS = NestedNameSpecifier::Create(S.Context, NNS, false,
                                    CoroTrait.getTypePtr());
  return S.Context.getElaboratedType(ETK_None, NNS, PromiseType);
};

if (!PromiseType->getAsCXXRecordDecl()) {
  S.Diag(FuncLoc,
         diag::err_implied_std_coroutine_traits_promise_type_not_class)
      << buildElaboratedType();
  return QualType();
}
if (S.RequireCompleteType(FuncLoc, buildElaboratedType(),
                          diag::err_coroutine_promise_type_incomplete))
  return QualType();

return PromiseType;
135}

137/// Look up the std::coroutine_handle<PromiseType>.
138static QualType lookupCoroutineHandleType(Sema &S, QualType PromiseType,
                                        SourceLocation Loc) {
if (PromiseType.isNull())
  return QualType();

NamespaceDecl *CoroNamespace = S.getStdNamespace();
assert(CoroNamespace && "Should already be diagnosed")(static_cast <bool> (CoroNamespace && "Should already be diagnosed"
) ? void (0) : __assert_fail ("CoroNamespace && \"Should already be diagnosed\""
, "clang/lib/Sema/SemaCoroutine.cpp", 144, __extension__ __PRETTY_FUNCTION__
));

LookupResult Result(S, &S.PP.getIdentifierTable().get("coroutine_handle"),
                    Loc, Sema::LookupOrdinaryName);
if (!S.LookupQualifiedName(Result, CoroNamespace)) {
  S.Diag(Loc, diag::err_implied_coroutine_type_not_found)
      << "std::coroutine_handle";
  return QualType();
}

ClassTemplateDecl *CoroHandle = Result.getAsSingle<ClassTemplateDecl>();
if (!CoroHandle) {
  Result.suppressDiagnostics();
  // We found something weird. Complain about the first thing we found.
  NamedDecl *Found = *Result.begin();
  S.Diag(Found->getLocation(), diag::err_malformed_std_coroutine_handle);
  return QualType();
}

// Form template argument list for coroutine_handle<Promise>.
TemplateArgumentListInfo Args(Loc, Loc);
Args.addArgument(TemplateArgumentLoc(
    TemplateArgument(PromiseType),
    S.Context.getTrivialTypeSourceInfo(PromiseType, Loc)));

// Build the template-id.
QualType CoroHandleType =
    S.CheckTemplateIdType(TemplateName(CoroHandle), Loc, Args);
if (CoroHandleType.isNull())
  return QualType();
if (S.RequireCompleteType(Loc, CoroHandleType,
                          diag::err_coroutine_type_missing_specialization))
  return QualType();

return CoroHandleType;
179}

181static bool isValidCoroutineContext(Sema &S, SourceLocation Loc,
                                  StringRef Keyword) {
// [expr.await]p2 dictates that 'co_await' and 'co_yield' must be used within
// a function body.
// FIXME: This also covers [expr.await]p2: "An await-expression shall not
// appear in a default argument." But the diagnostic QoI here could be
// improved to inform the user that default arguments specifically are not
// allowed.
auto *FD = dyn_cast<FunctionDecl>(S.CurContext);
if (!FD) {
  S.Diag(Loc, isa<ObjCMethodDecl>(S.CurContext)
                  ? diag::err_coroutine_objc_method
                  : diag::err_coroutine_outside_function) << Keyword;
  return false;
}

// An enumeration for mapping the diagnostic type to the correct diagnostic
// selection index.
enum InvalidFuncDiag {
  DiagCtor = 0,
  DiagDtor,
  DiagMain,
  DiagConstexpr,
  DiagAutoRet,
  DiagVarargs,
  DiagConsteval,
};
bool Diagnosed = false;
auto DiagInvalid = [&](InvalidFuncDiag ID) {
  S.Diag(Loc, diag::err_coroutine_invalid_func_context) << ID << Keyword;
  Diagnosed = true;
  return false;
};

// Diagnose when a constructor, destructor
// or the function 'main' are declared as a coroutine.
auto *MD = dyn_cast<CXXMethodDecl>(FD);
// [class.ctor]p11: "A constructor shall not be a coroutine."
if (MD && isa<CXXConstructorDecl>(MD))
  return DiagInvalid(DiagCtor);
// [class.dtor]p17: "A destructor shall not be a coroutine."
else if (MD && isa<CXXDestructorDecl>(MD))
  return DiagInvalid(DiagDtor);
// [basic.start.main]p3: "The function main shall not be a coroutine."
else if (FD->isMain())
  return DiagInvalid(DiagMain);

// Emit a diagnostics for each of the following conditions which is not met.
// [expr.const]p2: "An expression e is a core constant expression unless the
// evaluation of e [...] would evaluate one of the following expressions:
// [...] an await-expression [...] a yield-expression."
if (FD->isConstexpr())
  DiagInvalid(FD->isConsteval() ? DiagConsteval : DiagConstexpr);
// [dcl.spec.auto]p15: "A function declared with a return type that uses a
// placeholder type shall not be a coroutine."
if (FD->getReturnType()->isUndeducedType())
  DiagInvalid(DiagAutoRet);
// [dcl.fct.def.coroutine]p1
// The parameter-declaration-clause of the coroutine shall not terminate with
// an ellipsis that is not part of a parameter-declaration.
if (FD->isVariadic())
  DiagInvalid(DiagVarargs);

return !Diagnosed;
245}

247/// Build a call to 'operator co_await' if there is a suitable operator for
248/// the given expression.
249ExprResult Sema::BuildOperatorCoawaitCall(SourceLocation Loc, Expr *E,
                                        UnresolvedLookupExpr *Lookup) {
UnresolvedSet<16> Functions;
Functions.append(Lookup->decls_begin(), Lookup->decls_end());
return CreateOverloadedUnaryOp(Loc, UO_Coawait, Functions, E);
254}

256static ExprResult buildOperatorCoawaitCall(Sema &SemaRef, Scope *S,
                                         SourceLocation Loc, Expr *E) {
ExprResult R = SemaRef.BuildOperatorCoawaitLookupExpr(S, Loc);
if (R.isInvalid())
  return ExprError();
return SemaRef.BuildOperatorCoawaitCall(Loc, E,
                                        cast<UnresolvedLookupExpr>(R.get()));
263}

265static ExprResult buildCoroutineHandle(Sema &S, QualType PromiseType,
                                     SourceLocation Loc) {
QualType CoroHandleType = lookupCoroutineHandleType(S, PromiseType, Loc);
if (CoroHandleType.isNull())
  return ExprError();

DeclContext *LookupCtx = S.computeDeclContext(CoroHandleType);
LookupResult Found(S, &S.PP.getIdentifierTable().get("from_address"), Loc,
                   Sema::LookupOrdinaryName);
if (!S.LookupQualifiedName(Found, LookupCtx)) {
  S.Diag(Loc, diag::err_coroutine_handle_missing_member)
      << "from_address";
  return ExprError();
}

Expr *FramePtr =
    S.BuildBuiltinCallExpr(Loc, Builtin::BI__builtin_coro_frame, {});

CXXScopeSpec SS;
ExprResult FromAddr =
    S.BuildDeclarationNameExpr(SS, Found, /*NeedsADL=*/false);
if (FromAddr.isInvalid())
  return ExprError();

return S.BuildCallExpr(nullptr, FromAddr.get(), Loc, FramePtr, Loc);
290}

292struct ReadySuspendResumeResult {
enum AwaitCallType { ACT_Ready, ACT_Suspend, ACT_Resume };
Expr *Results[3];
OpaqueValueExpr *OpaqueValue;
bool IsInvalid;
297};

299static ExprResult buildMemberCall(Sema &S, Expr *Base, SourceLocation Loc,
                                StringRef Name, MultiExprArg Args) {
DeclarationNameInfo NameInfo(&S.PP.getIdentifierTable().get(Name), Loc);

// FIXME: Fix BuildMemberReferenceExpr to take a const CXXScopeSpec&.
CXXScopeSpec SS;
ExprResult Result = S.BuildMemberReferenceExpr(
    Base, Base->getType(), Loc, /*IsPtr=*/false, SS,
    SourceLocation(), nullptr, NameInfo, /*TemplateArgs=*/nullptr,
    /*Scope=*/nullptr);
if (Result.isInvalid())
  return ExprError();

// We meant exactly what we asked for. No need for typo correction.
if (auto *TE = dyn_cast<TypoExpr>(Result.get())) {
  S.clearDelayedTypo(TE);
  S.Diag(Loc, diag::err_no_member)
      << NameInfo.getName() << Base->getType()->getAsCXXRecordDecl()
      << Base->getSourceRange();
  return ExprError();
}

return S.BuildCallExpr(nullptr, Result.get(), Loc, Args, Loc, nullptr);
322}

324// See if return type is coroutine-handle and if so, invoke builtin coro-resume
325// on its address. This is to enable the support for coroutine-handle
326// returning await_suspend that results in a guaranteed tail call to the target
327// coroutine.
328static Expr *maybeTailCall(Sema &S, QualType RetType, Expr *E,
                         SourceLocation Loc) {
if (RetType->isReferenceType())
  return nullptr;
Type const *T = RetType.getTypePtr();
if (!T->isClassType() && !T->isStructureType())
  return nullptr;

// FIXME: Add convertability check to coroutine_handle<>. Possibly via
// EvaluateBinaryTypeTrait(BTT_IsConvertible, ...) which is at the moment
// a private function in SemaExprCXX.cpp

ExprResult AddressExpr = buildMemberCall(S, E, Loc, "address", std::nullopt);
if (AddressExpr.isInvalid())
  return nullptr;

Expr *JustAddress = AddressExpr.get();

// Check that the type of AddressExpr is void*
if (!JustAddress->getType().getTypePtr()->isVoidPointerType())
  S.Diag(cast<CallExpr>(JustAddress)->getCalleeDecl()->getLocation(),
         diag::warn_coroutine_handle_address_invalid_return_type)
      << JustAddress->getType();

// Clean up temporary objects so that they don't live across suspension points
// unnecessarily. We choose to clean up before the call to
// __builtin_coro_resume so that the cleanup code are not inserted in-between
// the resume call and return instruction, which would interfere with the
// musttail call contract.
JustAddress = S.MaybeCreateExprWithCleanups(JustAddress);
return S.BuildBuiltinCallExpr(Loc, Builtin::BI__builtin_coro_resume,
                              JustAddress);
360}

362/// Build calls to await_ready, await_suspend, and await_resume for a co_await
363/// expression.
364/// The generated AST tries to clean up temporary objects as early as
365/// possible so that they don't live across suspension points if possible.
366/// Having temporary objects living across suspension points unnecessarily can
367/// lead to large frame size, and also lead to memory corruptions if the
368/// coroutine frame is destroyed after coming back from suspension. This is done
369/// by wrapping both the await_ready call and the await_suspend call with
370/// ExprWithCleanups. In the end of this function, we also need to explicitly
371/// set cleanup state so that the CoawaitExpr is also wrapped with an
372/// ExprWithCleanups to clean up the awaiter associated with the co_await
373/// expression.
374static ReadySuspendResumeResult buildCoawaitCalls(Sema &S, VarDecl *CoroPromise,
                                                SourceLocation Loc, Expr *E) {
OpaqueValueExpr *Operand = new (S.Context)
    OpaqueValueExpr(Loc, E->getType(), VK_LValue, E->getObjectKind(), E);

// Assume valid until we see otherwise.
// Further operations are responsible for setting IsInalid to true.
ReadySuspendResumeResult Calls = {{}, Operand, /*IsInvalid=*/false};
31
←
'Calls.IsInvalid' initialized to 0, which participates in a condition later→
32
←
Initializing to a null pointer value→
33
←
'Calls' initialized here→

using ACT = ReadySuspendResumeResult::AwaitCallType;

auto BuildSubExpr = [&](ACT CallType, StringRef Func,
                        MultiExprArg Arg) -> Expr * {
  ExprResult Result = buildMemberCall(S, Operand, Loc, Func, Arg);
  if (Result.isInvalid()) {
    Calls.IsInvalid = true;
    return nullptr;
  }
  Calls.Results[CallType] = Result.get();
  return Result.get();
};

CallExpr *AwaitReady = cast_or_null<CallExpr>(
34
←
Assuming null pointer is passed into cast→
    BuildSubExpr(ACT::ACT_Ready, "await_ready", std::nullopt));
if (!AwaitReady34.1
'AwaitReady' is null
1
'AwaitReady' is null
1
'AwaitReady' is null
)
35
←
Taking true branch→
  return Calls;
36
←
The value 0 is assigned to 'RSS.IsInvalid', which participates in a condition later→
37
←
Storing null pointer value→
if (!AwaitReady->getType()->isDependentType()) {
  // [expr.await]p3 [...]
  // — await-ready is the expression e.await_ready(), contextually converted
  // to bool.
  ExprResult Conv = S.PerformContextuallyConvertToBool(AwaitReady);
  if (Conv.isInvalid()) {
    S.Diag(AwaitReady->getDirectCallee()->getBeginLoc(),
           diag::note_await_ready_no_bool_conversion);
    S.Diag(Loc, diag::note_coroutine_promise_call_implicitly_required)
        << AwaitReady->getDirectCallee() << E->getSourceRange();
    Calls.IsInvalid = true;
  } else
    Calls.Results[ACT::ACT_Ready] = S.MaybeCreateExprWithCleanups(Conv.get());
}

ExprResult CoroHandleRes =
    buildCoroutineHandle(S, CoroPromise->getType(), Loc);
if (CoroHandleRes.isInvalid()) {
  Calls.IsInvalid = true;
  return Calls;
}
Expr *CoroHandle = CoroHandleRes.get();
CallExpr *AwaitSuspend = cast_or_null<CallExpr>(
    BuildSubExpr(ACT::ACT_Suspend, "await_suspend", CoroHandle));
if (!AwaitSuspend)
  return Calls;
if (!AwaitSuspend->getType()->isDependentType()) {
  // [expr.await]p3 [...]
  //   - await-suspend is the expression e.await_suspend(h), which shall be
  //     a prvalue of type void, bool, or std::coroutine_handle<Z> for some
  //     type Z.
  QualType RetType = AwaitSuspend->getCallReturnType(S.Context);

  // Support for coroutine_handle returning await_suspend.
  if (Expr *TailCallSuspend =
          maybeTailCall(S, RetType, AwaitSuspend, Loc))
    // Note that we don't wrap the expression with ExprWithCleanups here
    // because that might interfere with tailcall contract (e.g. inserting
    // clean up instructions in-between tailcall and return). Instead
    // ExprWithCleanups is wrapped within maybeTailCall() prior to the resume
    // call.
    Calls.Results[ACT::ACT_Suspend] = TailCallSuspend;
  else {
    // non-class prvalues always have cv-unqualified types
    if (RetType->isReferenceType() ||
        (!RetType->isBooleanType() && !RetType->isVoidType())) {
      S.Diag(AwaitSuspend->getCalleeDecl()->getLocation(),
             diag::err_await_suspend_invalid_return_type)
          << RetType;
      S.Diag(Loc, diag::note_coroutine_promise_call_implicitly_required)
          << AwaitSuspend->getDirectCallee();
      Calls.IsInvalid = true;
    } else
      Calls.Results[ACT::ACT_Suspend] =
          S.MaybeCreateExprWithCleanups(AwaitSuspend);
  }
}

BuildSubExpr(ACT::ACT_Resume, "await_resume", std::nullopt);

// Make sure the awaiter object gets a chance to be cleaned up.
S.Cleanup.setExprNeedsCleanups(true);

return Calls;
464}

466static ExprResult buildPromiseCall(Sema &S, VarDecl *Promise,
                                 SourceLocation Loc, StringRef Name,
                                 MultiExprArg Args) {

// Form a reference to the promise.
ExprResult PromiseRef = S.BuildDeclRefExpr(
    Promise, Promise->getType().getNonReferenceType(), VK_LValue, Loc);
if (PromiseRef.isInvalid())
  return ExprError();

return buildMemberCall(S, PromiseRef.get(), Loc, Name, Args);
477}

479VarDecl *Sema::buildCoroutinePromise(SourceLocation Loc) {
assert(isa<FunctionDecl>(CurContext) && "not in a function scope")(static_cast <bool> (isa<FunctionDecl>(CurContext
) && "not in a function scope") ? void (0) : __assert_fail
 ("isa<FunctionDecl>(CurContext) && \"not in a function scope\""
, "clang/lib/Sema/SemaCoroutine.cpp", 480, __extension__ __PRETTY_FUNCTION__
));
auto *FD = cast<FunctionDecl>(CurContext);
bool IsThisDependentType = [&] {
  if (auto *MD = dyn_cast_or_null<CXXMethodDecl>(FD))
    return MD->isInstance() && MD->getThisType()->isDependentType();
  else
    return false;
}();

QualType T = FD->getType()->isDependentType() || IsThisDependentType
                 ? Context.DependentTy
                 : lookupPromiseType(*this, FD, Loc);
if (T.isNull())
  return nullptr;

auto *VD = VarDecl::Create(Context, FD, FD->getLocation(), FD->getLocation(),
                           &PP.getIdentifierTable().get("__promise"), T,
                           Context.getTrivialTypeSourceInfo(T, Loc), SC_None);
VD->setImplicit();
CheckVariableDeclarationType(VD);
if (VD->isInvalidDecl())
  return nullptr;

auto *ScopeInfo = getCurFunction();

// Build a list of arguments, based on the coroutine function's arguments,
// that if present will be passed to the promise type's constructor.
llvm::SmallVector<Expr *, 4> CtorArgExprs;

// Add implicit object parameter.
if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
  if (MD->isInstance() && !isLambdaCallOperator(MD)) {
    ExprResult ThisExpr = ActOnCXXThis(Loc);
    if (ThisExpr.isInvalid())
      return nullptr;
    ThisExpr = CreateBuiltinUnaryOp(Loc, UO_Deref, ThisExpr.get());
    if (ThisExpr.isInvalid())
      return nullptr;
    CtorArgExprs.push_back(ThisExpr.get());
  }
}

// Add the coroutine function's parameters.
auto &Moves = ScopeInfo->CoroutineParameterMoves;
for (auto *PD : FD->parameters()) {
  if (PD->getType()->isDependentType())
    continue;

  auto RefExpr = ExprEmpty();
  auto Move = Moves.find(PD);
  assert(Move != Moves.end() &&(static_cast <bool> (Move != Moves.end() && "Coroutine function parameter not inserted into move map"
) ? void (0) : __assert_fail ("Move != Moves.end() && \"Coroutine function parameter not inserted into move map\""
, "clang/lib/Sema/SemaCoroutine.cpp", 531, __extension__ __PRETTY_FUNCTION__
))
         "Coroutine function parameter not inserted into move map")(static_cast <bool> (Move != Moves.end() && "Coroutine function parameter not inserted into move map"
) ? void (0) : __assert_fail ("Move != Moves.end() && \"Coroutine function parameter not inserted into move map\""
, "clang/lib/Sema/SemaCoroutine.cpp", 531, __extension__ __PRETTY_FUNCTION__
));
  // If a reference to the function parameter exists in the coroutine
  // frame, use that reference.
  auto *MoveDecl =
      cast<VarDecl>(cast<DeclStmt>(Move->second)->getSingleDecl());
  RefExpr =
      BuildDeclRefExpr(MoveDecl, MoveDecl->getType().getNonReferenceType(),
                       ExprValueKind::VK_LValue, FD->getLocation());
  if (RefExpr.isInvalid())
    return nullptr;
  CtorArgExprs.push_back(RefExpr.get());
}

// If we have a non-zero number of constructor arguments, try to use them.
// Otherwise, fall back to the promise type's default constructor.
if (!CtorArgExprs.empty()) {
  // Create an initialization sequence for the promise type using the
  // constructor arguments, wrapped in a parenthesized list expression.
  Expr *PLE = ParenListExpr::Create(Context, FD->getLocation(),
                                    CtorArgExprs, FD->getLocation());
  InitializedEntity Entity = InitializedEntity::InitializeVariable(VD);
  InitializationKind Kind = InitializationKind::CreateForInit(
      VD->getLocation(), /*DirectInit=*/true, PLE);
  InitializationSequence InitSeq(*this, Entity, Kind, CtorArgExprs,
                                 /*TopLevelOfInitList=*/false,
                                 /*TreatUnavailableAsInvalid=*/false);

  // [dcl.fct.def.coroutine]5.7
  // promise-constructor-arguments is determined as follows: overload
  // resolution is performed on a promise constructor call created by
  // assembling an argument list  q_1 ... q_n . If a viable constructor is
  // found ([over.match.viable]), then promise-constructor-arguments is ( q_1
  // , ...,  q_n ), otherwise promise-constructor-arguments is empty.
  if (InitSeq) {
    ExprResult Result = InitSeq.Perform(*this, Entity, Kind, CtorArgExprs);
    if (Result.isInvalid()) {
      VD->setInvalidDecl();
    } else if (Result.get()) {
      VD->setInit(MaybeCreateExprWithCleanups(Result.get()));
      VD->setInitStyle(VarDecl::CallInit);
      CheckCompleteVariableDeclaration(VD);
    }
  } else
    ActOnUninitializedDecl(VD);
} else
  ActOnUninitializedDecl(VD);

FD->addDecl(VD);
return VD;
580}

582/// Check that this is a context in which a coroutine suspension can appear.
583static FunctionScopeInfo *checkCoroutineContext(Sema &S, SourceLocation Loc,
                                              StringRef Keyword,
                                              bool IsImplicit = false) {
if (!isValidCoroutineContext(S, Loc, Keyword))
  return nullptr;

assert(isa<FunctionDecl>(S.CurContext) && "not in a function scope")(static_cast <bool> (isa<FunctionDecl>(S.CurContext
) && "not in a function scope") ? void (0) : __assert_fail
 ("isa<FunctionDecl>(S.CurContext) && \"not in a function scope\""
, "clang/lib/Sema/SemaCoroutine.cpp", 589, __extension__ __PRETTY_FUNCTION__
));
9
←
Taking false branch→
10
←
Field 'CurContext' is a 'FunctionDecl'→
11
←
'?' condition is true→

auto *ScopeInfo = S.getCurFunction();
12
←
Calling 'Sema::getCurFunction'→
15
←
Returning from 'Sema::getCurFunction'→
assert(ScopeInfo && "missing function scope for function")(static_cast <bool> (ScopeInfo && "missing function scope for function"
) ? void (0) : __assert_fail ("ScopeInfo && \"missing function scope for function\""
, "clang/lib/Sema/SemaCoroutine.cpp", 592, __extension__ __PRETTY_FUNCTION__
));
16
←
Assuming 'ScopeInfo' is non-null→
17
←
'?' condition is true→

if (ScopeInfo->FirstCoroutineStmtLoc.isInvalid() && !IsImplicit)
  ScopeInfo->setFirstCoroutineStmt(Loc, Keyword);

if (ScopeInfo->CoroutinePromise)
18
←
Assuming field 'CoroutinePromise' is null→
19
←
Taking false branch→
  return ScopeInfo;

if (!S.buildCoroutineParameterMoves(Loc))
20
←
Taking false branch→
  return nullptr;

ScopeInfo->CoroutinePromise = S.buildCoroutinePromise(Loc);
if (!ScopeInfo->CoroutinePromise)
21
←
Assuming field 'CoroutinePromise' is non-null→
22
←
Taking false branch→
  return nullptr;

return ScopeInfo;
23
←
Returning pointer (loaded from 'ScopeInfo'), which participates in a condition later→
608}

610/// Recursively check \p E and all its children to see if any call target
611/// (including constructor call) is declared noexcept. Also any value returned
612/// from the call has a noexcept destructor.
613static void checkNoThrow(Sema &S, const Stmt *E,
                       llvm::SmallPtrSetImpl<const Decl *> &ThrowingDecls) {
auto checkDeclNoexcept = [&](const Decl *D, bool IsDtor = false) {
  // In the case of dtor, the call to dtor is implicit and hence we should
  // pass nullptr to canCalleeThrow.
  if (Sema::canCalleeThrow(S, IsDtor ? nullptr : cast<Expr>(E), D)) {
    if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
      // co_await promise.final_suspend() could end up calling
      // __builtin_coro_resume for symmetric transfer if await_suspend()
      // returns a handle. In that case, even __builtin_coro_resume is not
      // declared as noexcept and may throw, it does not throw _into_ the
      // coroutine that just suspended, but rather throws back out from
      // whoever called coroutine_handle::resume(), hence we claim that
      // logically it does not throw.
      if (FD->getBuiltinID() == Builtin::BI__builtin_coro_resume)
        return;
    }
    if (ThrowingDecls.empty()) {
      // [dcl.fct.def.coroutine]p15
      //   The expression co_await promise.final_suspend() shall not be
      //   potentially-throwing ([except.spec]).
      //
      // First time seeing an error, emit the error message.
      S.Diag(cast<FunctionDecl>(S.CurContext)->getLocation(),
             diag::err_coroutine_promise_final_suspend_requires_nothrow);
    }
    ThrowingDecls.insert(D);
  }
};

if (auto *CE = dyn_cast<CXXConstructExpr>(E)) {
  CXXConstructorDecl *Ctor = CE->getConstructor();
  checkDeclNoexcept(Ctor);
  // Check the corresponding destructor of the constructor.
  checkDeclNoexcept(Ctor->getParent()->getDestructor(), /*IsDtor=*/true);
} else if (auto *CE = dyn_cast<CallExpr>(E)) {
  if (CE->isTypeDependent())
    return;

  checkDeclNoexcept(CE->getCalleeDecl());
  QualType ReturnType = CE->getCallReturnType(S.getASTContext());
  // Check the destructor of the call return type, if any.
  if (ReturnType.isDestructedType() ==
      QualType::DestructionKind::DK_cxx_destructor) {
    const auto *T =
        cast<RecordType>(ReturnType.getCanonicalType().getTypePtr());
    checkDeclNoexcept(cast<CXXRecordDecl>(T->getDecl())->getDestructor(),
                      /*IsDtor=*/true);
  }
} else
  for (const auto *Child : E->children()) {
    if (!Child)
      continue;
    checkNoThrow(S, Child, ThrowingDecls);
  }
668}

670bool Sema::checkFinalSuspendNoThrow(const Stmt *FinalSuspend) {
llvm::SmallPtrSet<const Decl *, 4> ThrowingDecls;
// We first collect all declarations that should not throw but not declared
// with noexcept. We then sort them based on the location before printing.
// This is to avoid emitting the same note multiple times on the same
// declaration, and also provide a deterministic order for the messages.
checkNoThrow(*this, FinalSuspend, ThrowingDecls);
auto SortedDecls = llvm::SmallVector<const Decl *, 4>{ThrowingDecls.begin(),
                                                      ThrowingDecls.end()};
sort(SortedDecls, [](const Decl *A, const Decl *B) {
  return A->getEndLoc() < B->getEndLoc();
});
for (const auto *D : SortedDecls) {
  Diag(D->getEndLoc(), diag::note_coroutine_function_declare_noexcept);
}
return ThrowingDecls.empty();
686}

688bool Sema::ActOnCoroutineBodyStart(Scope *SC, SourceLocation KWLoc,
                                 StringRef Keyword) {
if (!checkCoroutineContext(*this, KWLoc, Keyword))
  return false;
auto *ScopeInfo = getCurFunction();
assert(ScopeInfo->CoroutinePromise)(static_cast <bool> (ScopeInfo->CoroutinePromise) ? void
 (0) : __assert_fail ("ScopeInfo->CoroutinePromise", "clang/lib/Sema/SemaCoroutine.cpp"
, 693, __extension__ __PRETTY_FUNCTION__));

// If we have existing coroutine statements then we have already built
// the initial and final suspend points.
if (!ScopeInfo->NeedsCoroutineSuspends)
  return true;

ScopeInfo->setNeedsCoroutineSuspends(false);

auto *Fn = cast<FunctionDecl>(CurContext);
SourceLocation Loc = Fn->getLocation();
// Build the initial suspend point
auto buildSuspends = [&](StringRef Name) mutable -> StmtResult {
  ExprResult Operand = buildPromiseCall(*this, ScopeInfo->CoroutinePromise,
                                        Loc, Name, std::nullopt);
  if (Operand.isInvalid())
    return StmtError();
  ExprResult Suspend =
      buildOperatorCoawaitCall(*this, SC, Loc, Operand.get());
  if (Suspend.isInvalid())
    return StmtError();
  Suspend = BuildResolvedCoawaitExpr(Loc, Operand.get(), Suspend.get(),
                                     /*IsImplicit*/ true);
  Suspend = ActOnFinishFullExpr(Suspend.get(), /*DiscardedValue*/ false);
  if (Suspend.isInvalid()) {
    Diag(Loc, diag::note_coroutine_promise_suspend_implicitly_required)
        << ((Name == "initial_suspend") ? 0 : 1);
    Diag(KWLoc, diag::note_declared_coroutine_here) << Keyword;
    return StmtError();
  }
  return cast<Stmt>(Suspend.get());
};

StmtResult InitSuspend = buildSuspends("initial_suspend");
if (InitSuspend.isInvalid())
  return true;

StmtResult FinalSuspend = buildSuspends("final_suspend");
if (FinalSuspend.isInvalid() || !checkFinalSuspendNoThrow(FinalSuspend.get()))
  return true;

ScopeInfo->setCoroutineSuspends(InitSuspend.get(), FinalSuspend.get());

return true;
737}

739// Recursively walks up the scope hierarchy until either a 'catch' or a function
740// scope is found, whichever comes first.
741static bool isWithinCatchScope(Scope *S) {
// 'co_await' and 'co_yield' keywords are disallowed within catch blocks, but
// lambdas that use 'co_await' are allowed. The loop below ends when a
// function scope is found in order to ensure the following behavior:
//
// void foo() {      // <- function scope
//   try {           //
//     co_await x;   // <- 'co_await' is OK within a function scope
//   } catch {       // <- catch scope
//     co_await x;   // <- 'co_await' is not OK within a catch scope
//     []() {        // <- function scope
//       co_await x; // <- 'co_await' is OK within a function scope
//     }();
//   }
// }
while (S && !S->isFunctionScope()) {
  if (S->isCatchScope())
    return true;
  S = S->getParent();
}
return false;
762}

764// [expr.await]p2, emphasis added: "An await-expression shall appear only in
765// a *potentially evaluated* expression within the compound-statement of a
766// function-body *outside of a handler* [...] A context within a function
767// where an await-expression can appear is called a suspension context of the
768// function."
769static bool checkSuspensionContext(Sema &S, SourceLocation Loc,
                                 StringRef Keyword) {
// First emphasis of [expr.await]p2: must be a potentially evaluated context.
// That is, 'co_await' and 'co_yield' cannot appear in subexpressions of
// \c sizeof.
if (S.isUnevaluatedContext()) {
  S.Diag(Loc, diag::err_coroutine_unevaluated_context) << Keyword;
  return false;
}

// Second emphasis of [expr.await]p2: must be outside of an exception handler.
if (isWithinCatchScope(S.getCurScope())) {
  S.Diag(Loc, diag::err_coroutine_within_handler) << Keyword;
  return false;
}

return true;
786}

788ExprResult Sema::ActOnCoawaitExpr(Scope *S, SourceLocation Loc, Expr *E) {
if (!checkSuspensionContext(*this, Loc, "co_await"))
  return ExprError();

if (!ActOnCoroutineBodyStart(S, Loc, "co_await")) {
  CorrectDelayedTyposInExpr(E);
  return ExprError();
}

if (E->hasPlaceholderType()) {
  ExprResult R = CheckPlaceholderExpr(E);
  if (R.isInvalid()) return ExprError();
  E = R.get();
}
ExprResult Lookup = BuildOperatorCoawaitLookupExpr(S, Loc);
if (Lookup.isInvalid())
  return ExprError();
return BuildUnresolvedCoawaitExpr(Loc, E,
                                 cast<UnresolvedLookupExpr>(Lookup.get()));
807}

809ExprResult Sema::BuildOperatorCoawaitLookupExpr(Scope *S, SourceLocation Loc) {
DeclarationName OpName =
    Context.DeclarationNames.getCXXOperatorName(OO_Coawait);
LookupResult Operators(*this, OpName, SourceLocation(),
                       Sema::LookupOperatorName);
LookupName(Operators, S);

assert(!Operators.isAmbiguous() && "Operator lookup cannot be ambiguous")(static_cast <bool> (!Operators.isAmbiguous() &&
 "Operator lookup cannot be ambiguous") ? void (0) : __assert_fail
 ("!Operators.isAmbiguous() && \"Operator lookup cannot be ambiguous\""
, "clang/lib/Sema/SemaCoroutine.cpp", 816, __extension__ __PRETTY_FUNCTION__
));
const auto &Functions = Operators.asUnresolvedSet();
bool IsOverloaded =
    Functions.size() > 1 ||
    (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin()));
Expr *CoawaitOp = UnresolvedLookupExpr::Create(
    Context, /*NamingClass*/ nullptr, NestedNameSpecifierLoc(),
    DeclarationNameInfo(OpName, Loc), /*RequiresADL*/ true, IsOverloaded,
    Functions.begin(), Functions.end());
assert(CoawaitOp)(static_cast <bool> (CoawaitOp) ? void (0) : __assert_fail
 ("CoawaitOp", "clang/lib/Sema/SemaCoroutine.cpp", 825, __extension__
 __PRETTY_FUNCTION__));
return CoawaitOp;
827}

829// Attempts to resolve and build a CoawaitExpr from "raw" inputs, bailing out to
830// DependentCoawaitExpr if needed.
831ExprResult Sema::BuildUnresolvedCoawaitExpr(SourceLocation Loc, Expr *Operand,
                                          UnresolvedLookupExpr *Lookup) {
auto *FSI = checkCoroutineContext(*this, Loc, "co_await");
if (!FSI)
  return ExprError();

if (Operand->hasPlaceholderType()) {
  ExprResult R = CheckPlaceholderExpr(Operand);
  if (R.isInvalid())
    return ExprError();
  Operand = R.get();
}

auto *Promise = FSI->CoroutinePromise;
if (Promise->getType()->isDependentType()) {
  Expr *Res = new (Context)
      DependentCoawaitExpr(Loc, Context.DependentTy, Operand, Lookup);
  return Res;
}

auto *RD = Promise->getType()->getAsCXXRecordDecl();
auto *Transformed = Operand;
if (lookupMember(*this, "await_transform", RD, Loc)) {
  ExprResult R =
      buildPromiseCall(*this, Promise, Loc, "await_transform", Operand);
  if (R.isInvalid()) {
    Diag(Loc,
         diag::note_coroutine_promise_implicit_await_transform_required_here)
        << Operand->getSourceRange();
    return ExprError();
  }
  Transformed = R.get();
}
ExprResult Awaiter = BuildOperatorCoawaitCall(Loc, Transformed, Lookup);
if (Awaiter.isInvalid())
  return ExprError();

return BuildResolvedCoawaitExpr(Loc, Operand, Awaiter.get());
869}

871ExprResult Sema::BuildResolvedCoawaitExpr(SourceLocation Loc, Expr *Operand,
                                        Expr *Awaiter, bool IsImplicit) {
auto *Coroutine = checkCoroutineContext(*this, Loc, "co_await", IsImplicit);
if (!Coroutine)
  return ExprError();

if (Awaiter->hasPlaceholderType()) {
  ExprResult R = CheckPlaceholderExpr(Awaiter);
  if (R.isInvalid()) return ExprError();
  Awaiter = R.get();
}

if (Awaiter->getType()->isDependentType()) {
  Expr *Res = new (Context)
      CoawaitExpr(Loc, Context.DependentTy, Operand, Awaiter, IsImplicit);
  return Res;
}

// If the expression is a temporary, materialize it as an lvalue so that we
// can use it multiple times.
if (Awaiter->isPRValue())
  Awaiter = CreateMaterializeTemporaryExpr(Awaiter->getType(), Awaiter, true);

// The location of the `co_await` token cannot be used when constructing
// the member call expressions since it's before the location of `Expr`, which
// is used as the start of the member call expression.
SourceLocation CallLoc = Awaiter->getExprLoc();

// Build the await_ready, await_suspend, await_resume calls.
ReadySuspendResumeResult RSS =
    buildCoawaitCalls(*this, Coroutine->CoroutinePromise, CallLoc, Awaiter);
if (RSS.IsInvalid)
  return ExprError();

Expr *Res = new (Context)
    CoawaitExpr(Loc, Operand, Awaiter, RSS.Results[0], RSS.Results[1],
                RSS.Results[2], RSS.OpaqueValue, IsImplicit);

return Res;
910}

912ExprResult Sema::ActOnCoyieldExpr(Scope *S, SourceLocation Loc, Expr *E) {
if (!checkSuspensionContext(*this, Loc, "co_yield"))
1
Taking false branch→
  return ExprError();

if (!ActOnCoroutineBodyStart(S, Loc, "co_yield")) {
2
←
Taking false branch→
  CorrectDelayedTyposInExpr(E);
  return ExprError();
}

// Build yield_value call.
ExprResult Awaitable = buildPromiseCall(
    *this, getCurFunction()->CoroutinePromise, Loc, "yield_value", E);
if (Awaitable.isInvalid())
3
←
Assuming the condition is false→
4
←
Taking false branch→
  return ExprError();

// Build 'operator co_await' call.
Awaitable = buildOperatorCoawaitCall(*this, S, Loc, Awaitable.get());
if (Awaitable.isInvalid())
5
←
Assuming the condition is false→
6
←
Taking false branch→
  return ExprError();

return BuildCoyieldExpr(Loc, Awaitable.get());
7
←
Calling 'Sema::BuildCoyieldExpr'→
933}
934ExprResult Sema::BuildCoyieldExpr(SourceLocation Loc, Expr *E) {
auto *Coroutine = checkCoroutineContext(*this, Loc, "co_yield");
8
←
Calling 'checkCoroutineContext'→
24
←
Returning from 'checkCoroutineContext'→
if (!Coroutine24.1
'Coroutine' is non-null
1
'Coroutine' is non-null
1
'Coroutine' is non-null
)
25
←
Taking false branch→
  return ExprError();

if (E->hasPlaceholderType()) {
26
←
Taking false branch→
  ExprResult R = CheckPlaceholderExpr(E);
  if (R.isInvalid()) return ExprError();
  E = R.get();
}

Expr *Operand = E;

if (E->getType()->isDependentType()) {
27
←
Assuming the condition is false→
28
←
Taking false branch→
  Expr *Res = new (Context) CoyieldExpr(Loc, Context.DependentTy, Operand, E);
  return Res;
}

// If the expression is a temporary, materialize it as an lvalue so that we
// can use it multiple times.
if (E->isPRValue())
29
←
Taking false branch→
  E = CreateMaterializeTemporaryExpr(E->getType(), E, true);

// Build the await_ready, await_suspend, await_resume calls.
ReadySuspendResumeResult RSS = buildCoawaitCalls(
30
←
Calling 'buildCoawaitCalls'→
38
←
Returning from 'buildCoawaitCalls'→
    *this, Coroutine->CoroutinePromise, Loc, E);
if (RSS.IsInvalid38.1
Field 'IsInvalid' is false
1
Field 'IsInvalid' is false
1
Field 'IsInvalid' is false
)
39
←
Taking false branch→
  return ExprError();

Expr *Res =
    new (Context) CoyieldExpr(Loc, Operand, E, RSS.Results[0], RSS.Results[1],
41
←
Calling constructor for 'CoyieldExpr'→
                              RSS.Results[2], RSS.OpaqueValue);
40
←
Passing null pointer value via 6th parameter 'Resume'→

return Res;
968}

970StmtResult Sema::ActOnCoreturnStmt(Scope *S, SourceLocation Loc, Expr *E) {
if (!ActOnCoroutineBodyStart(S, Loc, "co_return")) {
  CorrectDelayedTyposInExpr(E);
  return StmtError();
}
return BuildCoreturnStmt(Loc, E);
976}

978StmtResult Sema::BuildCoreturnStmt(SourceLocation Loc, Expr *E,
                                 bool IsImplicit) {
auto *FSI = checkCoroutineContext(*this, Loc, "co_return", IsImplicit);
if (!FSI)
  return StmtError();

if (E && E->hasPlaceholderType() &&
    !E->hasPlaceholderType(BuiltinType::Overload)) {
  ExprResult R = CheckPlaceholderExpr(E);
  if (R.isInvalid()) return StmtError();
  E = R.get();
}

VarDecl *Promise = FSI->CoroutinePromise;
ExprResult PC;
if (E && (isa<InitListExpr>(E) || !E->getType()->isVoidType())) {
  getNamedReturnInfo(E, SimplerImplicitMoveMode::ForceOn);
  PC = buildPromiseCall(*this, Promise, Loc, "return_value", E);
} else {
  E = MakeFullDiscardedValueExpr(E).get();
  PC = buildPromiseCall(*this, Promise, Loc, "return_void", std::nullopt);
}
if (PC.isInvalid())
  return StmtError();

Expr *PCE = ActOnFinishFullExpr(PC.get(), /*DiscardedValue*/ false).get();

Stmt *Res = new (Context) CoreturnStmt(Loc, E, PCE, IsImplicit);
return Res;
1007}

1009/// Look up the std::nothrow object.
1010static Expr *buildStdNoThrowDeclRef(Sema &S, SourceLocation Loc) {
NamespaceDecl *Std = S.getStdNamespace();
assert(Std && "Should already be diagnosed")(static_cast <bool> (Std && "Should already be diagnosed"
) ? void (0) : __assert_fail ("Std && \"Should already be diagnosed\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1012, __extension__ __PRETTY_FUNCTION__
));

LookupResult Result(S, &S.PP.getIdentifierTable().get("nothrow"), Loc,
                    Sema::LookupOrdinaryName);
if (!S.LookupQualifiedName(Result, Std)) {
  // <coroutine> is not requred to include <new>, so we couldn't omit
  // the check here.
  S.Diag(Loc, diag::err_implicit_coroutine_std_nothrow_type_not_found);
  return nullptr;
}

auto *VD = Result.getAsSingle<VarDecl>();
if (!VD) {
  Result.suppressDiagnostics();
  // We found something weird. Complain about the first thing we found.
  NamedDecl *Found = *Result.begin();
  S.Diag(Found->getLocation(), diag::err_malformed_std_nothrow);
  return nullptr;
}

ExprResult DR = S.BuildDeclRefExpr(VD, VD->getType(), VK_LValue, Loc);
if (DR.isInvalid())
  return nullptr;

return DR.get();
1037}

1039static TypeSourceInfo *getTypeSourceInfoForStdAlignValT(Sema &S,
                                                      SourceLocation Loc) {
EnumDecl *StdAlignValT = S.getStdAlignValT();
QualType StdAlignValDecl = S.Context.getTypeDeclType(StdAlignValT);
return S.Context.getTrivialTypeSourceInfo(StdAlignValDecl);
1044}

1046// Find an appropriate delete for the promise.
1047static bool findDeleteForPromise(Sema &S, SourceLocation Loc, QualType PromiseType,
                               FunctionDecl *&OperatorDelete) {
DeclarationName DeleteName =
    S.Context.DeclarationNames.getCXXOperatorName(OO_Delete);

auto *PointeeRD = PromiseType->getAsCXXRecordDecl();
assert(PointeeRD && "PromiseType must be a CxxRecordDecl type")(static_cast <bool> (PointeeRD && "PromiseType must be a CxxRecordDecl type"
) ? void (0) : __assert_fail ("PointeeRD && \"PromiseType must be a CxxRecordDecl type\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1053, __extension__ __PRETTY_FUNCTION__
));

const bool Overaligned = S.getLangOpts().CoroAlignedAllocation;

// [dcl.fct.def.coroutine]p12
// The deallocation function's name is looked up by searching for it in the
// scope of the promise type. If nothing is found, a search is performed in
// the global scope.
if (S.FindDeallocationFunction(Loc, PointeeRD, DeleteName, OperatorDelete,
                               /*Diagnose*/ true, /*WantSize*/ true,
                               /*WantAligned*/ Overaligned))
  return false;

// [dcl.fct.def.coroutine]p12
//   If both a usual deallocation function with only a pointer parameter and a
//   usual deallocation function with both a pointer parameter and a size
//   parameter are found, then the selected deallocation function shall be the
//   one with two parameters. Otherwise, the selected deallocation function
//   shall be the function with one parameter.
if (!OperatorDelete) {
  // Look for a global declaration.
  // Coroutines can always provide their required size.
  const bool CanProvideSize = true;
  // Sema::FindUsualDeallocationFunction will try to find the one with two
  // parameters first. It will return the deallocation function with one
  // parameter if failed.
  OperatorDelete = S.FindUsualDeallocationFunction(Loc, CanProvideSize,
                                                   Overaligned, DeleteName);

  if (!OperatorDelete)
    return false;
}

S.MarkFunctionReferenced(Loc, OperatorDelete);
return true;
1088}


1091void Sema::CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body) {
FunctionScopeInfo *Fn = getCurFunction();
assert(Fn && Fn->isCoroutine() && "not a coroutine")(static_cast <bool> (Fn && Fn->isCoroutine()
 && "not a coroutine") ? void (0) : __assert_fail ("Fn && Fn->isCoroutine() && \"not a coroutine\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1093, __extension__ __PRETTY_FUNCTION__
));
if (!Body) {
  assert(FD->isInvalidDecl() &&(static_cast <bool> (FD->isInvalidDecl() && "a null body is only allowed for invalid declarations"
) ? void (0) : __assert_fail ("FD->isInvalidDecl() && \"a null body is only allowed for invalid declarations\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1096, __extension__ __PRETTY_FUNCTION__
))
         "a null body is only allowed for invalid declarations")(static_cast <bool> (FD->isInvalidDecl() && "a null body is only allowed for invalid declarations"
) ? void (0) : __assert_fail ("FD->isInvalidDecl() && \"a null body is only allowed for invalid declarations\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1096, __extension__ __PRETTY_FUNCTION__
));
  return;
}
// We have a function that uses coroutine keywords, but we failed to build
// the promise type.
if (!Fn->CoroutinePromise)
  return FD->setInvalidDecl();

if (isa<CoroutineBodyStmt>(Body)) {
  // Nothing todo. the body is already a transformed coroutine body statement.
  return;
}

// The always_inline attribute doesn't reliably apply to a coroutine,
// because the coroutine will be split into pieces and some pieces
// might be called indirectly, as in a virtual call. Even the ramp
// function cannot be inlined at -O0, due to pipeline ordering
// problems (see https://llvm.org/PR53413). Tell the user about it.
if (FD->hasAttr<AlwaysInlineAttr>())
  Diag(FD->getLocation(), diag::warn_always_inline_coroutine);

// [stmt.return.coroutine]p1:
//   A coroutine shall not enclose a return statement ([stmt.return]).
if (Fn->FirstReturnLoc.isValid()) {
  assert(Fn->FirstCoroutineStmtLoc.isValid() &&(static_cast <bool> (Fn->FirstCoroutineStmtLoc.isValid
() && "first coroutine location not set") ? void (0) :
 __assert_fail ("Fn->FirstCoroutineStmtLoc.isValid() && \"first coroutine location not set\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1121, __extension__ __PRETTY_FUNCTION__
))
                 "first coroutine location not set")(static_cast <bool> (Fn->FirstCoroutineStmtLoc.isValid
() && "first coroutine location not set") ? void (0) :
 __assert_fail ("Fn->FirstCoroutineStmtLoc.isValid() && \"first coroutine location not set\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1121, __extension__ __PRETTY_FUNCTION__
));
  Diag(Fn->FirstReturnLoc, diag::err_return_in_coroutine);
  Diag(Fn->FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
          << Fn->getFirstCoroutineStmtKeyword();
}

// Coroutines will get splitted into pieces. The GNU address of label
// extension wouldn't be meaningful in coroutines.
for (AddrLabelExpr *ALE : Fn->AddrLabels)
  Diag(ALE->getBeginLoc(), diag::err_coro_invalid_addr_of_label);

CoroutineStmtBuilder Builder(*this, *FD, *Fn, Body);
if (Builder.isInvalid() || !Builder.buildStatements())
  return FD->setInvalidDecl();

// Build body for the coroutine wrapper statement.
Body = CoroutineBodyStmt::Create(Context, Builder);
1138}

1140CoroutineStmtBuilder::CoroutineStmtBuilder(Sema &S, FunctionDecl &FD,
                                         sema::FunctionScopeInfo &Fn,
                                         Stmt *Body)
  : S(S), FD(FD), Fn(Fn), Loc(FD.getLocation()),
    IsPromiseDependentType(
        !Fn.CoroutinePromise ||
        Fn.CoroutinePromise->getType()->isDependentType()) {
this->Body = Body;

for (auto KV : Fn.CoroutineParameterMoves)
  this->ParamMovesVector.push_back(KV.second);
this->ParamMoves = this->ParamMovesVector;

if (!IsPromiseDependentType) {
  PromiseRecordDecl = Fn.CoroutinePromise->getType()->getAsCXXRecordDecl();
  assert(PromiseRecordDecl && "Type should have already been checked")(static_cast <bool> (PromiseRecordDecl && "Type should have already been checked"
) ? void (0) : __assert_fail ("PromiseRecordDecl && \"Type should have already been checked\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1155, __extension__ __PRETTY_FUNCTION__
));
}
this->IsValid = makePromiseStmt() && makeInitialAndFinalSuspend();
1158}

1160bool CoroutineStmtBuilder::buildStatements() {
assert(this->IsValid && "coroutine already invalid")(static_cast <bool> (this->IsValid && "coroutine already invalid"
) ? void (0) : __assert_fail ("this->IsValid && \"coroutine already invalid\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1161, __extension__ __PRETTY_FUNCTION__
));
this->IsValid = makeReturnObject();
if (this->IsValid && !IsPromiseDependentType)
  buildDependentStatements();
return this->IsValid;
1166}

1168bool CoroutineStmtBuilder::buildDependentStatements() {
assert(this->IsValid && "coroutine already invalid")(static_cast <bool> (this->IsValid && "coroutine already invalid"
) ? void (0) : __assert_fail ("this->IsValid && \"coroutine already invalid\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1169, __extension__ __PRETTY_FUNCTION__
));
assert(!this->IsPromiseDependentType &&(static_cast <bool> (!this->IsPromiseDependentType &&
 "coroutine cannot have a dependent promise type") ? void (0)
 : __assert_fail ("!this->IsPromiseDependentType && \"coroutine cannot have a dependent promise type\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1171, __extension__ __PRETTY_FUNCTION__
))
       "coroutine cannot have a dependent promise type")(static_cast <bool> (!this->IsPromiseDependentType &&
 "coroutine cannot have a dependent promise type") ? void (0)
 : __assert_fail ("!this->IsPromiseDependentType && \"coroutine cannot have a dependent promise type\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1171, __extension__ __PRETTY_FUNCTION__
));
this->IsValid = makeOnException() && makeOnFallthrough() &&
                makeGroDeclAndReturnStmt() && makeReturnOnAllocFailure() &&
                makeNewAndDeleteExpr();
return this->IsValid;
1176}

1178bool CoroutineStmtBuilder::makePromiseStmt() {
// Form a declaration statement for the promise declaration, so that AST
// visitors can more easily find it.
StmtResult PromiseStmt =
    S.ActOnDeclStmt(S.ConvertDeclToDeclGroup(Fn.CoroutinePromise), Loc, Loc);
if (PromiseStmt.isInvalid())
  return false;

this->Promise = PromiseStmt.get();
return true;
1188}

1190bool CoroutineStmtBuilder::makeInitialAndFinalSuspend() {
if (Fn.hasInvalidCoroutineSuspends())
  return false;
this->InitialSuspend = cast<Expr>(Fn.CoroutineSuspends.first);
this->FinalSuspend = cast<Expr>(Fn.CoroutineSuspends.second);
return true;
1196}

1198static bool diagReturnOnAllocFailure(Sema &S, Expr *E,
                                   CXXRecordDecl *PromiseRecordDecl,
                                   FunctionScopeInfo &Fn) {
auto Loc = E->getExprLoc();
if (auto *DeclRef = dyn_cast_or_null<DeclRefExpr>(E)) {
  auto *Decl = DeclRef->getDecl();
  if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(Decl)) {
    if (Method->isStatic())
      return true;
    else
      Loc = Decl->getLocation();
  }
}

S.Diag(
    Loc,
    diag::err_coroutine_promise_get_return_object_on_allocation_failure)
    << PromiseRecordDecl;
S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
    << Fn.getFirstCoroutineStmtKeyword();
return false;
1219}

1221bool CoroutineStmtBuilder::makeReturnOnAllocFailure() {
assert(!IsPromiseDependentType &&(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1223, __extension__ __PRETTY_FUNCTION__
))
       "cannot make statement while the promise type is dependent")(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1223, __extension__ __PRETTY_FUNCTION__
));

// [dcl.fct.def.coroutine]p10
//   If a search for the name get_return_object_on_allocation_failure in
// the scope of the promise type ([class.member.lookup]) finds any
// declarations, then the result of a call to an allocation function used to
// obtain storage for the coroutine state is assumed to return nullptr if it
// fails to obtain storage, ... If the allocation function returns nullptr,
// ... and the return value is obtained by a call to
// T::get_return_object_on_allocation_failure(), where T is the
// promise type.
DeclarationName DN =
    S.PP.getIdentifierInfo("get_return_object_on_allocation_failure");
LookupResult Found(S, DN, Loc, Sema::LookupMemberName);
if (!S.LookupQualifiedName(Found, PromiseRecordDecl))
  return true;

CXXScopeSpec SS;
ExprResult DeclNameExpr =
    S.BuildDeclarationNameExpr(SS, Found, /*NeedsADL=*/false);
if (DeclNameExpr.isInvalid())
  return false;

if (!diagReturnOnAllocFailure(S, DeclNameExpr.get(), PromiseRecordDecl, Fn))
  return false;

ExprResult ReturnObjectOnAllocationFailure =
    S.BuildCallExpr(nullptr, DeclNameExpr.get(), Loc, {}, Loc);
if (ReturnObjectOnAllocationFailure.isInvalid())
  return false;

StmtResult ReturnStmt =
    S.BuildReturnStmt(Loc, ReturnObjectOnAllocationFailure.get());
if (ReturnStmt.isInvalid()) {
  S.Diag(Found.getFoundDecl()->getLocation(), diag::note_member_declared_here)
      << DN;
  S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
      << Fn.getFirstCoroutineStmtKeyword();
  return false;
}

this->ReturnStmtOnAllocFailure = ReturnStmt.get();
return true;
1266}

1268// Collect placement arguments for allocation function of coroutine FD.
1269// Return true if we collect placement arguments succesfully. Return false,
1270// otherwise.
1271static bool collectPlacementArgs(Sema &S, FunctionDecl &FD, SourceLocation Loc,
                               SmallVectorImpl<Expr *> &PlacementArgs) {
if (auto *MD = dyn_cast<CXXMethodDecl>(&FD)) {
  if (MD->isInstance() && !isLambdaCallOperator(MD)) {
    ExprResult ThisExpr = S.ActOnCXXThis(Loc);
    if (ThisExpr.isInvalid())
      return false;
    ThisExpr = S.CreateBuiltinUnaryOp(Loc, UO_Deref, ThisExpr.get());
    if (ThisExpr.isInvalid())
      return false;
    PlacementArgs.push_back(ThisExpr.get());
  }
}

for (auto *PD : FD.parameters()) {
  if (PD->getType()->isDependentType())
    continue;

  // Build a reference to the parameter.
  auto PDLoc = PD->getLocation();
  ExprResult PDRefExpr =
      S.BuildDeclRefExpr(PD, PD->getOriginalType().getNonReferenceType(),
                         ExprValueKind::VK_LValue, PDLoc);
  if (PDRefExpr.isInvalid())
    return false;

  PlacementArgs.push_back(PDRefExpr.get());
}

return true;
1301}

1303bool CoroutineStmtBuilder::makeNewAndDeleteExpr() {
// Form and check allocation and deallocation calls.
assert(!IsPromiseDependentType &&(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1306, __extension__ __PRETTY_FUNCTION__
))
       "cannot make statement while the promise type is dependent")(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1306, __extension__ __PRETTY_FUNCTION__
));
QualType PromiseType = Fn.CoroutinePromise->getType();

if (S.RequireCompleteType(Loc, PromiseType, diag::err_incomplete_type))
  return false;

const bool RequiresNoThrowAlloc = ReturnStmtOnAllocFailure != nullptr;

// According to [dcl.fct.def.coroutine]p9, Lookup allocation functions using a
// parameter list composed of the requested size of the coroutine state being
// allocated, followed by the coroutine function's arguments. If a matching
// allocation function exists, use it. Otherwise, use an allocation function
// that just takes the requested size.
//
// [dcl.fct.def.coroutine]p9
//   An implementation may need to allocate additional storage for a
//   coroutine.
// This storage is known as the coroutine state and is obtained by calling a
// non-array allocation function ([basic.stc.dynamic.allocation]). The
// allocation function's name is looked up by searching for it in the scope of
// the promise type.
// - If any declarations are found, overload resolution is performed on a
// function call created by assembling an argument list. The first argument is
// the amount of space requested, and has type std::size_t. The
// lvalues p1 ... pn are the succeeding arguments.
//
// ...where "p1 ... pn" are defined earlier as:
//
// [dcl.fct.def.coroutine]p3
//   The promise type of a coroutine is `std::coroutine_traits<R, P1, ...,
//   Pn>`
// , where R is the return type of the function, and `P1, ..., Pn` are the
// sequence of types of the non-object function parameters, preceded by the
// type of the object parameter ([dcl.fct]) if the coroutine is a non-static
// member function. [dcl.fct.def.coroutine]p4 In the following, p_i is an
// lvalue of type P_i, where p1 denotes the object parameter and p_i+1 denotes
// the i-th non-object function parameter for a non-static member function,
// and p_i denotes the i-th function parameter otherwise. For a non-static
// member function, q_1 is an lvalue that denotes *this; any other q_i is an
// lvalue that denotes the parameter copy corresponding to p_i.

FunctionDecl *OperatorNew = nullptr;
SmallVector<Expr *, 1> PlacementArgs;

const bool PromiseContainsNew = [this, &PromiseType]() -> bool {
  DeclarationName NewName =
      S.getASTContext().DeclarationNames.getCXXOperatorName(OO_New);
  LookupResult R(S, NewName, Loc, Sema::LookupOrdinaryName);

  if (PromiseType->isRecordType())
    S.LookupQualifiedName(R, PromiseType->getAsCXXRecordDecl());

  return !R.empty() && !R.isAmbiguous();
}();

// Helper function to indicate whether the last lookup found the aligned
// allocation function.
bool PassAlignment = S.getLangOpts().CoroAlignedAllocation;
auto LookupAllocationFunction = [&](Sema::AllocationFunctionScope NewScope =
                                        Sema::AFS_Both,
                                    bool WithoutPlacementArgs = false,
                                    bool ForceNonAligned = false) {
  // [dcl.fct.def.coroutine]p9
  //   The allocation function's name is looked up by searching for it in the
  // scope of the promise type.
  // - If any declarations are found, ...
  // - If no declarations are found in the scope of the promise type, a search
  // is performed in the global scope.
  if (NewScope == Sema::AFS_Both)
    NewScope = PromiseContainsNew ? Sema::AFS_Class : Sema::AFS_Global;

  PassAlignment = !ForceNonAligned && S.getLangOpts().CoroAlignedAllocation;
  FunctionDecl *UnusedResult = nullptr;
  S.FindAllocationFunctions(Loc, SourceRange(), NewScope,
                            /*DeleteScope*/ Sema::AFS_Both, PromiseType,
                            /*isArray*/ false, PassAlignment,
                            WithoutPlacementArgs ? MultiExprArg{}
                                                 : PlacementArgs,
                            OperatorNew, UnusedResult, /*Diagnose*/ false);
};

// We don't expect to call to global operator new with (size, p0, …, pn).
// So if we choose to lookup the allocation function in global scope, we
// shouldn't lookup placement arguments.
if (PromiseContainsNew && !collectPlacementArgs(S, FD, Loc, PlacementArgs))
  return false;

LookupAllocationFunction();

if (PromiseContainsNew && !PlacementArgs.empty()) {
  // [dcl.fct.def.coroutine]p9
  //   If no viable function is found ([over.match.viable]), overload
  //   resolution
  // is performed again on a function call created by passing just the amount
  // of space required as an argument of type std::size_t.
  //
  // Proposed Change of [dcl.fct.def.coroutine]p9 in P2014R0:
  //   Otherwise, overload resolution is performed again on a function call
  //   created
  // by passing the amount of space requested as an argument of type
  // std::size_t as the first argument, and the requested alignment as
  // an argument of type std:align_val_t as the second argument.
  if (!OperatorNew ||
      (S.getLangOpts().CoroAlignedAllocation && !PassAlignment))
    LookupAllocationFunction(/*NewScope*/ Sema::AFS_Class,
                             /*WithoutPlacementArgs*/ true);
}

// Proposed Change of [dcl.fct.def.coroutine]p12 in P2014R0:
//   Otherwise, overload resolution is performed again on a function call
//   created
// by passing the amount of space requested as an argument of type
// std::size_t as the first argument, and the lvalues p1 ... pn as the
// succeeding arguments. Otherwise, overload resolution is performed again
// on a function call created by passing just the amount of space required as
// an argument of type std::size_t.
//
// So within the proposed change in P2014RO, the priority order of aligned
// allocation functions wiht promise_type is:
//
//    void* operator new( std::size_t, std::align_val_t, placement_args... );
//    void* operator new( std::size_t, std::align_val_t);
//    void* operator new( std::size_t, placement_args... );
//    void* operator new( std::size_t);

// Helper variable to emit warnings.
bool FoundNonAlignedInPromise = false;
if (PromiseContainsNew && S.getLangOpts().CoroAlignedAllocation)
  if (!OperatorNew || !PassAlignment) {
    FoundNonAlignedInPromise = OperatorNew;

    LookupAllocationFunction(/*NewScope*/ Sema::AFS_Class,
                             /*WithoutPlacementArgs*/ false,
                             /*ForceNonAligned*/ true);

    if (!OperatorNew && !PlacementArgs.empty())
      LookupAllocationFunction(/*NewScope*/ Sema::AFS_Class,
                               /*WithoutPlacementArgs*/ true,
                               /*ForceNonAligned*/ true);
  }

bool IsGlobalOverload =
    OperatorNew && !isa<CXXRecordDecl>(OperatorNew->getDeclContext());
// If we didn't find a class-local new declaration and non-throwing new
// was is required then we need to lookup the non-throwing global operator
// instead.
if (RequiresNoThrowAlloc && (!OperatorNew || IsGlobalOverload)) {
  auto *StdNoThrow = buildStdNoThrowDeclRef(S, Loc);
  if (!StdNoThrow)
    return false;
  PlacementArgs = {StdNoThrow};
  OperatorNew = nullptr;
  LookupAllocationFunction(Sema::AFS_Global);
}

// If we found a non-aligned allocation function in the promise_type,
// it indicates the user forgot to update the allocation function. Let's emit
// a warning here.
if (FoundNonAlignedInPromise) {
  S.Diag(OperatorNew->getLocation(),
         diag::warn_non_aligned_allocation_function)
      << &FD;
}

if (!OperatorNew) {
  if (PromiseContainsNew)
    S.Diag(Loc, diag::err_coroutine_unusable_new) << PromiseType << &FD;
  else if (RequiresNoThrowAlloc)
    S.Diag(Loc, diag::err_coroutine_unfound_nothrow_new)
        << &FD << S.getLangOpts().CoroAlignedAllocation;

  return false;
}

if (RequiresNoThrowAlloc) {
  const auto *FT = OperatorNew->getType()->castAs<FunctionProtoType>();
  if (!FT->isNothrow(/*ResultIfDependent*/ false)) {
    S.Diag(OperatorNew->getLocation(),
           diag::err_coroutine_promise_new_requires_nothrow)
        << OperatorNew;
    S.Diag(Loc, diag::note_coroutine_promise_call_implicitly_required)
        << OperatorNew;
    return false;
  }
}

FunctionDecl *OperatorDelete = nullptr;
if (!findDeleteForPromise(S, Loc, PromiseType, OperatorDelete)) {
  // FIXME: We should add an error here. According to:
  // [dcl.fct.def.coroutine]p12
  //   If no usual deallocation function is found, the program is ill-formed.
  return false;
}

Expr *FramePtr =
    S.BuildBuiltinCallExpr(Loc, Builtin::BI__builtin_coro_frame, {});

Expr *FrameSize =
    S.BuildBuiltinCallExpr(Loc, Builtin::BI__builtin_coro_size, {});

Expr *FrameAlignment = nullptr;

if (S.getLangOpts().CoroAlignedAllocation) {
  FrameAlignment =
      S.BuildBuiltinCallExpr(Loc, Builtin::BI__builtin_coro_align, {});

  TypeSourceInfo *AlignValTy = getTypeSourceInfoForStdAlignValT(S, Loc);
  if (!AlignValTy)
    return false;

  FrameAlignment = S.BuildCXXNamedCast(Loc, tok::kw_static_cast, AlignValTy,
                                       FrameAlignment, SourceRange(Loc, Loc),
                                       SourceRange(Loc, Loc))
                       .get();
}

// Make new call.
ExprResult NewRef =
    S.BuildDeclRefExpr(OperatorNew, OperatorNew->getType(), VK_LValue, Loc);
if (NewRef.isInvalid())
  return false;

SmallVector<Expr *, 2> NewArgs(1, FrameSize);
if (S.getLangOpts().CoroAlignedAllocation && PassAlignment)
  NewArgs.push_back(FrameAlignment);

if (OperatorNew->getNumParams() > NewArgs.size())
  llvm::append_range(NewArgs, PlacementArgs);

ExprResult NewExpr =
    S.BuildCallExpr(S.getCurScope(), NewRef.get(), Loc, NewArgs, Loc);
NewExpr = S.ActOnFinishFullExpr(NewExpr.get(), /*DiscardedValue*/ false);
if (NewExpr.isInvalid())
  return false;

// Make delete call.

QualType OpDeleteQualType = OperatorDelete->getType();

ExprResult DeleteRef =
    S.BuildDeclRefExpr(OperatorDelete, OpDeleteQualType, VK_LValue, Loc);
if (DeleteRef.isInvalid())
  return false;

Expr *CoroFree =
    S.BuildBuiltinCallExpr(Loc, Builtin::BI__builtin_coro_free, {FramePtr});

SmallVector<Expr *, 2> DeleteArgs{CoroFree};

// [dcl.fct.def.coroutine]p12
//   The selected deallocation function shall be called with the address of
//   the block of storage to be reclaimed as its first argument. If a
//   deallocation function with a parameter of type std::size_t is
//   used, the size of the block is passed as the corresponding argument.
const auto *OpDeleteType =
    OpDeleteQualType.getTypePtr()->castAs<FunctionProtoType>();
if (OpDeleteType->getNumParams() > DeleteArgs.size() &&
    S.getASTContext().hasSameUnqualifiedType(
        OpDeleteType->getParamType(DeleteArgs.size()), FrameSize->getType()))
  DeleteArgs.push_back(FrameSize);

// Proposed Change of [dcl.fct.def.coroutine]p12 in P2014R0:
//   If deallocation function lookup finds a usual deallocation function with
//   a pointer parameter, size parameter and alignment parameter then this
//   will be the selected deallocation function, otherwise if lookup finds a
//   usual deallocation function with both a pointer parameter and a size
//   parameter, then this will be the selected deallocation function.
//   Otherwise, if lookup finds a usual deallocation function with only a
//   pointer parameter, then this will be the selected deallocation
//   function.
//
// So we are not forced to pass alignment to the deallocation function.
if (S.getLangOpts().CoroAlignedAllocation &&
    OpDeleteType->getNumParams() > DeleteArgs.size() &&
    S.getASTContext().hasSameUnqualifiedType(
        OpDeleteType->getParamType(DeleteArgs.size()),
        FrameAlignment->getType()))
  DeleteArgs.push_back(FrameAlignment);

ExprResult DeleteExpr =
    S.BuildCallExpr(S.getCurScope(), DeleteRef.get(), Loc, DeleteArgs, Loc);
DeleteExpr =
    S.ActOnFinishFullExpr(DeleteExpr.get(), /*DiscardedValue*/ false);
if (DeleteExpr.isInvalid())
  return false;

this->Allocate = NewExpr.get();
this->Deallocate = DeleteExpr.get();

return true;
1596}

1598bool CoroutineStmtBuilder::makeOnFallthrough() {
assert(!IsPromiseDependentType &&(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1600, __extension__ __PRETTY_FUNCTION__
))
       "cannot make statement while the promise type is dependent")(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1600, __extension__ __PRETTY_FUNCTION__
));

// [dcl.fct.def.coroutine]/p6
// If searches for the names return_void and return_value in the scope of
// the promise type each find any declarations, the program is ill-formed.
// [Note 1: If return_void is found, flowing off the end of a coroutine is
// equivalent to a co_return with no operand. Otherwise, flowing off the end
// of a coroutine results in undefined behavior ([stmt.return.coroutine]). —
// end note]
bool HasRVoid, HasRValue;
LookupResult LRVoid =
    lookupMember(S, "return_void", PromiseRecordDecl, Loc, HasRVoid);
LookupResult LRValue =
    lookupMember(S, "return_value", PromiseRecordDecl, Loc, HasRValue);

StmtResult Fallthrough;
if (HasRVoid && HasRValue) {
  // FIXME Improve this diagnostic
  S.Diag(FD.getLocation(),
         diag::err_coroutine_promise_incompatible_return_functions)
      << PromiseRecordDecl;
  S.Diag(LRVoid.getRepresentativeDecl()->getLocation(),
         diag::note_member_first_declared_here)
      << LRVoid.getLookupName();
  S.Diag(LRValue.getRepresentativeDecl()->getLocation(),
         diag::note_member_first_declared_here)
      << LRValue.getLookupName();
  return false;
} else if (!HasRVoid && !HasRValue) {
  // We need to set 'Fallthrough'. Otherwise the other analysis part might
  // think the coroutine has defined a return_value method. So it might emit
  // **false** positive warning. e.g.,
  //
  //    promise_without_return_func foo() {
  //        co_await something();
  //    }
  //
  // Then AnalysisBasedWarning would emit a warning about `foo()` lacking a
  // co_return statements, which isn't correct.
  Fallthrough = S.ActOnNullStmt(PromiseRecordDecl->getLocation());
  if (Fallthrough.isInvalid())
    return false;
} else if (HasRVoid) {
  Fallthrough = S.BuildCoreturnStmt(FD.getLocation(), nullptr,
                                    /*IsImplicit*/false);
  Fallthrough = S.ActOnFinishFullStmt(Fallthrough.get());
  if (Fallthrough.isInvalid())
    return false;
}

this->OnFallthrough = Fallthrough.get();
return true;
1652}

1654bool CoroutineStmtBuilder::makeOnException() {
// Try to form 'p.unhandled_exception();'
assert(!IsPromiseDependentType &&(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1657, __extension__ __PRETTY_FUNCTION__
))
       "cannot make statement while the promise type is dependent")(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1657, __extension__ __PRETTY_FUNCTION__
));

const bool RequireUnhandledException = S.getLangOpts().CXXExceptions;

if (!lookupMember(S, "unhandled_exception", PromiseRecordDecl, Loc)) {
  auto DiagID =
      RequireUnhandledException
          ? diag::err_coroutine_promise_unhandled_exception_required
          : diag::
                warn_coroutine_promise_unhandled_exception_required_with_exceptions;
  S.Diag(Loc, DiagID) << PromiseRecordDecl;
  S.Diag(PromiseRecordDecl->getLocation(), diag::note_defined_here)
      << PromiseRecordDecl;
  return !RequireUnhandledException;
}

// If exceptions are disabled, don't try to build OnException.
if (!S.getLangOpts().CXXExceptions)
  return true;

ExprResult UnhandledException = buildPromiseCall(
    S, Fn.CoroutinePromise, Loc, "unhandled_exception", std::nullopt);
UnhandledException = S.ActOnFinishFullExpr(UnhandledException.get(), Loc,
                                           /*DiscardedValue*/ false);
if (UnhandledException.isInvalid())
  return false;

// Since the body of the coroutine will be wrapped in try-catch, it will
// be incompatible with SEH __try if present in a function.
if (!S.getLangOpts().Borland && Fn.FirstSEHTryLoc.isValid()) {
  S.Diag(Fn.FirstSEHTryLoc, diag::err_seh_in_a_coroutine_with_cxx_exceptions);
  S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
      << Fn.getFirstCoroutineStmtKeyword();
  return false;
}

this->OnException = UnhandledException.get();
return true;
1695}

1697bool CoroutineStmtBuilder::makeReturnObject() {
// [dcl.fct.def.coroutine]p7
// The expression promise.get_return_object() is used to initialize the
// returned reference or prvalue result object of a call to a coroutine.
ExprResult ReturnObject = buildPromiseCall(S, Fn.CoroutinePromise, Loc,
                                           "get_return_object", std::nullopt);
if (ReturnObject.isInvalid())
  return false;

this->ReturnValue = ReturnObject.get();
return true;
1708}

1710static void noteMemberDeclaredHere(Sema &S, Expr *E, FunctionScopeInfo &Fn) {
if (auto *MbrRef = dyn_cast<CXXMemberCallExpr>(E)) {
  auto *MethodDecl = MbrRef->getMethodDecl();
  S.Diag(MethodDecl->getLocation(), diag::note_member_declared_here)
      << MethodDecl;
}
S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
    << Fn.getFirstCoroutineStmtKeyword();
1718}

1720bool CoroutineStmtBuilder::makeGroDeclAndReturnStmt() {
assert(!IsPromiseDependentType &&(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1722, __extension__ __PRETTY_FUNCTION__
))
       "cannot make statement while the promise type is dependent")(static_cast <bool> (!IsPromiseDependentType &&
 "cannot make statement while the promise type is dependent")
 ? void (0) : __assert_fail ("!IsPromiseDependentType && \"cannot make statement while the promise type is dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1722, __extension__ __PRETTY_FUNCTION__
));
assert(this->ReturnValue && "ReturnValue must be already formed")(static_cast <bool> (this->ReturnValue && "ReturnValue must be already formed"
) ? void (0) : __assert_fail ("this->ReturnValue && \"ReturnValue must be already formed\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1723, __extension__ __PRETTY_FUNCTION__
));

QualType const GroType = this->ReturnValue->getType();
assert(!GroType->isDependentType() &&(static_cast <bool> (!GroType->isDependentType() &&
 "get_return_object type must no longer be dependent") ? void
 (0) : __assert_fail ("!GroType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1727, __extension__ __PRETTY_FUNCTION__
))
       "get_return_object type must no longer be dependent")(static_cast <bool> (!GroType->isDependentType() &&
 "get_return_object type must no longer be dependent") ? void
 (0) : __assert_fail ("!GroType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1727, __extension__ __PRETTY_FUNCTION__
));

QualType const FnRetType = FD.getReturnType();
assert(!FnRetType->isDependentType() &&(static_cast <bool> (!FnRetType->isDependentType() &&
 "get_return_object type must no longer be dependent") ? void
 (0) : __assert_fail ("!FnRetType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1731, __extension__ __PRETTY_FUNCTION__
))
       "get_return_object type must no longer be dependent")(static_cast <bool> (!FnRetType->isDependentType() &&
 "get_return_object type must no longer be dependent") ? void
 (0) : __assert_fail ("!FnRetType->isDependentType() && \"get_return_object type must no longer be dependent\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1731, __extension__ __PRETTY_FUNCTION__
));

// The call to get_­return_­object is sequenced before the call to
// initial_­suspend and is invoked at most once, but there are caveats
// regarding on whether the prvalue result object may be initialized
// directly/eager or delayed, depending on the types involved.
//
// More info at https://github.com/cplusplus/papers/issues/1414
bool GroMatchesRetType = S.getASTContext().hasSameType(GroType, FnRetType);

if (FnRetType->isVoidType()) {
  ExprResult Res =
      S.ActOnFinishFullExpr(this->ReturnValue, Loc, /*DiscardedValue*/ false);
  if (Res.isInvalid())
    return false;

  if (!GroMatchesRetType)
    this->ResultDecl = Res.get();
  return true;
}

if (GroType->isVoidType()) {
  // Trigger a nice error message.
  InitializedEntity Entity =
      InitializedEntity::InitializeResult(Loc, FnRetType);
  S.PerformCopyInitialization(Entity, SourceLocation(), ReturnValue);
  noteMemberDeclaredHere(S, ReturnValue, Fn);
  return false;
}

StmtResult ReturnStmt;
clang::VarDecl *GroDecl = nullptr;
if (GroMatchesRetType) {
  ReturnStmt = S.BuildReturnStmt(Loc, ReturnValue);
} else {
  GroDecl = VarDecl::Create(
      S.Context, &FD, FD.getLocation(), FD.getLocation(),
      &S.PP.getIdentifierTable().get("__coro_gro"), GroType,
      S.Context.getTrivialTypeSourceInfo(GroType, Loc), SC_None);
  GroDecl->setImplicit();

  S.CheckVariableDeclarationType(GroDecl);
  if (GroDecl->isInvalidDecl())
    return false;

  InitializedEntity Entity = InitializedEntity::InitializeVariable(GroDecl);
  ExprResult Res =
      S.PerformCopyInitialization(Entity, SourceLocation(), ReturnValue);
  if (Res.isInvalid())
    return false;

  Res = S.ActOnFinishFullExpr(Res.get(), /*DiscardedValue*/ false);
  if (Res.isInvalid())
    return false;

  S.AddInitializerToDecl(GroDecl, Res.get(),
                         /*DirectInit=*/false);

  S.FinalizeDeclaration(GroDecl);

  // Form a declaration statement for the return declaration, so that AST
  // visitors can more easily find it.
  StmtResult GroDeclStmt =
      S.ActOnDeclStmt(S.ConvertDeclToDeclGroup(GroDecl), Loc, Loc);
  if (GroDeclStmt.isInvalid())
    return false;

  this->ResultDecl = GroDeclStmt.get();

  ExprResult declRef = S.BuildDeclRefExpr(GroDecl, GroType, VK_LValue, Loc);
  if (declRef.isInvalid())
    return false;

  ReturnStmt = S.BuildReturnStmt(Loc, declRef.get());
}

if (ReturnStmt.isInvalid()) {
  noteMemberDeclaredHere(S, ReturnValue, Fn);
  return false;
}

if (!GroMatchesRetType &&
    cast<clang::ReturnStmt>(ReturnStmt.get())->getNRVOCandidate() == GroDecl)
  GroDecl->setNRVOVariable(true);

this->ReturnStmt = ReturnStmt.get();
return true;
1818}

1820// Create a static_cast\<T&&>(expr).
1821static Expr *castForMoving(Sema &S, Expr *E, QualType T = QualType()) {
if (T.isNull())
  T = E->getType();
QualType TargetType = S.BuildReferenceType(
    T, /*SpelledAsLValue*/ false, SourceLocation(), DeclarationName());
SourceLocation ExprLoc = E->getBeginLoc();
TypeSourceInfo *TargetLoc =
    S.Context.getTrivialTypeSourceInfo(TargetType, ExprLoc);

return S
    .BuildCXXNamedCast(ExprLoc, tok::kw_static_cast, TargetLoc, E,
                       SourceRange(ExprLoc, ExprLoc), E->getSourceRange())
    .get();
1834}

1836/// Build a variable declaration for move parameter.
1837static VarDecl *buildVarDecl(Sema &S, SourceLocation Loc, QualType Type,
                           IdentifierInfo *II) {
TypeSourceInfo *TInfo = S.Context.getTrivialTypeSourceInfo(Type, Loc);
VarDecl *Decl = VarDecl::Create(S.Context, S.CurContext, Loc, Loc, II, Type,
                                TInfo, SC_None);
Decl->setImplicit();
return Decl;
1844}

1846// Build statements that move coroutine function parameters to the coroutine
1847// frame, and store them on the function scope info.
1848bool Sema::buildCoroutineParameterMoves(SourceLocation Loc) {
assert(isa<FunctionDecl>(CurContext) && "not in a function scope")(static_cast <bool> (isa<FunctionDecl>(CurContext
) && "not in a function scope") ? void (0) : __assert_fail
 ("isa<FunctionDecl>(CurContext) && \"not in a function scope\""
, "clang/lib/Sema/SemaCoroutine.cpp", 1849, __extension__ __PRETTY_FUNCTION__
));
auto *FD = cast<FunctionDecl>(CurContext);

auto *ScopeInfo = getCurFunction();
if (!ScopeInfo->CoroutineParameterMoves.empty())
  return false;

// [dcl.fct.def.coroutine]p13
//   When a coroutine is invoked, after initializing its parameters
//   ([expr.call]), a copy is created for each coroutine parameter. For a
//   parameter of type cv T, the copy is a variable of type cv T with
//   automatic storage duration that is direct-initialized from an xvalue of
//   type T referring to the parameter.
for (auto *PD : FD->parameters()) {
  if (PD->getType()->isDependentType())
    continue;

  ExprResult PDRefExpr =
      BuildDeclRefExpr(PD, PD->getType().getNonReferenceType(),
                       ExprValueKind::VK_LValue, Loc); // FIXME: scope?
  if (PDRefExpr.isInvalid())
    return false;

  Expr *CExpr = nullptr;
  if (PD->getType()->getAsCXXRecordDecl() ||
      PD->getType()->isRValueReferenceType())
    CExpr = castForMoving(*this, PDRefExpr.get());
  else
    CExpr = PDRefExpr.get();
  // [dcl.fct.def.coroutine]p13
  //   The initialization and destruction of each parameter copy occurs in the
  //   context of the called coroutine.
  auto *D = buildVarDecl(*this, Loc, PD->getType(), PD->getIdentifier());
  AddInitializerToDecl(D, CExpr, /*DirectInit=*/true);

  // Convert decl to a statement.
  StmtResult Stmt = ActOnDeclStmt(ConvertDeclToDeclGroup(D), Loc, Loc);
  if (Stmt.isInvalid())
    return false;

  ScopeInfo->CoroutineParameterMoves.insert(std::make_pair(PD, Stmt.get()));
}
return true;
1892}

1894StmtResult Sema::BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs Args) {
CoroutineBodyStmt *Res = CoroutineBodyStmt::Create(Context, Args);
if (!Res)
  return StmtError();
return Res;
1899}

1901ClassTemplateDecl *Sema::lookupCoroutineTraits(SourceLocation KwLoc,
                                             SourceLocation FuncLoc) {
if (StdCoroutineTraitsCache)
  return StdCoroutineTraitsCache;

IdentifierInfo const &TraitIdent =
    PP.getIdentifierTable().get("coroutine_traits");

NamespaceDecl *StdSpace = getStdNamespace();
LookupResult Result(*this, &TraitIdent, FuncLoc, LookupOrdinaryName);
bool Found = StdSpace && LookupQualifiedName(Result, StdSpace);

if (!Found) {
  // The goggles, we found nothing!
  Diag(KwLoc, diag::err_implied_coroutine_type_not_found)
      << "std::coroutine_traits";
  return nullptr;
}

// coroutine_traits is required to be a class template.
StdCoroutineTraitsCache = Result.getAsSingle<ClassTemplateDecl>();
if (!StdCoroutineTraitsCache) {
  Result.suppressDiagnostics();
  NamedDecl *Found = *Result.begin();
  Diag(Found->getLocation(), diag::err_malformed_std_coroutine_traits);
  return nullptr;
}

return StdCoroutineTraitsCache;
1930}

←

/build/source/clang/include/clang/Sema/Sema.h

→

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

14#ifndef LLVM_CLANG_SEMA_SEMA_H
15#define LLVM_CLANG_SEMA_SEMA_H

17#include "clang/AST/ASTConcept.h"
18#include "clang/AST/ASTFwd.h"
19#include "clang/AST/Attr.h"
20#include "clang/AST/Availability.h"
21#include "clang/AST/ComparisonCategories.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/DeclarationName.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/ExprConcepts.h"
27#include "clang/AST/ExprObjC.h"
28#include "clang/AST/ExprOpenMP.h"
29#include "clang/AST/ExternalASTSource.h"
30#include "clang/AST/LocInfoType.h"
31#include "clang/AST/MangleNumberingContext.h"
32#include "clang/AST/NSAPI.h"
33#include "clang/AST/PrettyPrinter.h"
34#include "clang/AST/StmtCXX.h"
35#include "clang/AST/StmtOpenMP.h"
36#include "clang/AST/TypeLoc.h"
37#include "clang/AST/TypeOrdering.h"
38#include "clang/Basic/BitmaskEnum.h"
39#include "clang/Basic/Builtins.h"
40#include "clang/Basic/DarwinSDKInfo.h"
41#include "clang/Basic/ExpressionTraits.h"
42#include "clang/Basic/Module.h"
43#include "clang/Basic/OpenCLOptions.h"
44#include "clang/Basic/OpenMPKinds.h"
45#include "clang/Basic/PragmaKinds.h"
46#include "clang/Basic/Specifiers.h"
47#include "clang/Basic/TemplateKinds.h"
48#include "clang/Basic/TypeTraits.h"
49#include "clang/Sema/AnalysisBasedWarnings.h"
50#include "clang/Sema/CleanupInfo.h"
51#include "clang/Sema/DeclSpec.h"
52#include "clang/Sema/ExternalSemaSource.h"
53#include "clang/Sema/IdentifierResolver.h"
54#include "clang/Sema/ObjCMethodList.h"
55#include "clang/Sema/Ownership.h"
56#include "clang/Sema/Scope.h"
57#include "clang/Sema/SemaConcept.h"
58#include "clang/Sema/TypoCorrection.h"
59#include "clang/Sema/Weak.h"
60#include "llvm/ADT/ArrayRef.h"
61#include "llvm/ADT/SetVector.h"
62#include "llvm/ADT/SmallBitVector.h"
63#include "llvm/ADT/SmallPtrSet.h"
64#include "llvm/ADT/SmallSet.h"
65#include "llvm/ADT/SmallVector.h"
66#include "llvm/ADT/TinyPtrVector.h"
67#include "llvm/Frontend/OpenMP/OMPConstants.h"
68#include <deque>
69#include <memory>
70#include <optional>
71#include <string>
72#include <tuple>
73#include <vector>

75namespace llvm {
class APSInt;
template <typename ValueT, typename ValueInfoT> class DenseSet;
class SmallBitVector;
struct InlineAsmIdentifierInfo;
80}

82namespace clang {
class ADLResult;
class ASTConsumer;
class ASTContext;
class ASTMutationListener;
class ASTReader;
class ASTWriter;
class ArrayType;
class ParsedAttr;
class BindingDecl;
class BlockDecl;
class CapturedDecl;
class CXXBasePath;
class CXXBasePaths;
class CXXBindTemporaryExpr;
typedef SmallVector<CXXBaseSpecifier*, 4> CXXCastPath;
class CXXConstructorDecl;
class CXXConversionDecl;
class CXXDeleteExpr;
class CXXDestructorDecl;
class CXXFieldCollector;
class CXXMemberCallExpr;
class CXXMethodDecl;
class CXXScopeSpec;
class CXXTemporary;
class CXXTryStmt;
class CallExpr;
class ClassTemplateDecl;
class ClassTemplatePartialSpecializationDecl;
class ClassTemplateSpecializationDecl;
class VarTemplatePartialSpecializationDecl;
class CodeCompleteConsumer;
class CodeCompletionAllocator;
class CodeCompletionTUInfo;
class CodeCompletionResult;
class CoroutineBodyStmt;
class Decl;
class DeclAccessPair;
class DeclContext;
class DeclRefExpr;
class DeclaratorDecl;
class DeducedTemplateArgument;
class DependentDiagnostic;
class DesignatedInitExpr;
class Designation;
class EnableIfAttr;
class EnumConstantDecl;
class Expr;
class ExtVectorType;
class FormatAttr;
class FriendDecl;
class FunctionDecl;
class FunctionProtoType;
class FunctionTemplateDecl;
class ImplicitConversionSequence;
typedef MutableArrayRef<ImplicitConversionSequence> ConversionSequenceList;
class InitListExpr;
class InitializationKind;
class InitializationSequence;
class InitializedEntity;
class IntegerLiteral;
class LabelStmt;
class LambdaExpr;
class LangOptions;
class LocalInstantiationScope;
class LookupResult;
class MacroInfo;
typedef ArrayRef<std::pair<IdentifierInfo *, SourceLocation>> ModuleIdPath;
class ModuleLoader;
class MultiLevelTemplateArgumentList;
class NamedDecl;
class ObjCCategoryDecl;
class ObjCCategoryImplDecl;
class ObjCCompatibleAliasDecl;
class ObjCContainerDecl;
class ObjCImplDecl;
class ObjCImplementationDecl;
class ObjCInterfaceDecl;
class ObjCIvarDecl;
template <class T> class ObjCList;
class ObjCMessageExpr;
class ObjCMethodDecl;
class ObjCPropertyDecl;
class ObjCProtocolDecl;
class OMPThreadPrivateDecl;
class OMPRequiresDecl;
class OMPDeclareReductionDecl;
class OMPDeclareSimdDecl;
class OMPClause;
struct OMPVarListLocTy;
struct OverloadCandidate;
enum class OverloadCandidateParamOrder : char;
enum OverloadCandidateRewriteKind : unsigned;
class OverloadCandidateSet;
class OverloadExpr;
class ParenListExpr;
class ParmVarDecl;
class Preprocessor;
class PseudoDestructorTypeStorage;
class PseudoObjectExpr;
class QualType;
class StandardConversionSequence;
class Stmt;
class StringLiteral;
class SwitchStmt;
class TemplateArgument;
class TemplateArgumentList;
class TemplateArgumentLoc;
class TemplateDecl;
class TemplateInstantiationCallback;
class TemplateParameterList;
class TemplatePartialOrderingContext;
class TemplateTemplateParmDecl;
class Token;
class TypeAliasDecl;
class TypedefDecl;
class TypedefNameDecl;
class TypeLoc;
class TypoCorrectionConsumer;
class UnqualifiedId;
class UnresolvedLookupExpr;
class UnresolvedMemberExpr;
class UnresolvedSetImpl;
class UnresolvedSetIterator;
class UsingDecl;
class UsingShadowDecl;
class ValueDecl;
class VarDecl;
class VarTemplateSpecializationDecl;
class VisibilityAttr;
class VisibleDeclConsumer;
class IndirectFieldDecl;
struct DeductionFailureInfo;
class TemplateSpecCandidateSet;

217namespace sema {
class AccessedEntity;
class BlockScopeInfo;
class Capture;
class CapturedRegionScopeInfo;
class CapturingScopeInfo;
class CompoundScopeInfo;
class DelayedDiagnostic;
class DelayedDiagnosticPool;
class FunctionScopeInfo;
class LambdaScopeInfo;
class PossiblyUnreachableDiag;
class RISCVIntrinsicManager;
class SemaPPCallbacks;
class TemplateDeductionInfo;
232}

234namespace threadSafety {
class BeforeSet;
void threadSafetyCleanup(BeforeSet* Cache);
237}

239// FIXME: No way to easily map from TemplateTypeParmTypes to
240// TemplateTypeParmDecls, so we have this horrible PointerUnion.
241typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType *, NamedDecl *>,
                SourceLocation>
  UnexpandedParameterPack;

245/// Describes whether we've seen any nullability information for the given
246/// file.
247struct FileNullability {
/// The first pointer declarator (of any pointer kind) in the file that does
/// not have a corresponding nullability annotation.
SourceLocation PointerLoc;

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

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

/// Whether we saw any type nullability annotations in the given file.
bool SawTypeNullability = false;
261};

263/// A mapping from file IDs to a record of whether we've seen nullability
264/// information in that file.
265class FileNullabilityMap {
/// A mapping from file IDs to the nullability information for each file ID.
llvm::DenseMap<FileID, FileNullability> Map;

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

275public:
FileNullability &operator[](FileID file) {
  // Check the single-element cache.
  if (file == Cache.File)
    return Cache.Nullability;

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

  // Pull this entry into the cache.
  Cache.File = file;
  Cache.Nullability = Map[file];
  return Cache.Nullability;
}
291};

293/// Tracks expected type during expression parsing, for use in code completion.
294/// The type is tied to a particular token, all functions that update or consume
295/// the type take a start location of the token they are looking at as a
296/// parameter. This avoids updating the type on hot paths in the parser.
297class PreferredTypeBuilder {
298public:
PreferredTypeBuilder(bool Enabled) : Enabled(Enabled) {}

void enterCondition(Sema &S, SourceLocation Tok);
void enterReturn(Sema &S, SourceLocation Tok);
void enterVariableInit(SourceLocation Tok, Decl *D);
/// Handles e.g. BaseType{ .D = Tok...
void enterDesignatedInitializer(SourceLocation Tok, QualType BaseType,
                                const Designation &D);
/// Computing a type for the function argument may require running
/// overloading, so we postpone its computation until it is actually needed.
///
/// Clients should be very careful when using this function, as it stores a
/// function_ref, clients should make sure all calls to get() with the same
/// location happen while function_ref is alive.
///
/// The callback should also emit signature help as a side-effect, but only
/// if the completion point has been reached.
void enterFunctionArgument(SourceLocation Tok,
                           llvm::function_ref<QualType()> ComputeType);

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

/// Get the expected type associated with this location, if any.
///
/// If the location is a function argument, determining the expected type
/// involves considering all function overloads and the arguments so far.
/// In this case, signature help for these function overloads will be reported
/// as a side-effect (only if the completion point has been reached).
QualType get(SourceLocation Tok) const {
  if (!Enabled || Tok != ExpectedLoc)
    return QualType();
  if (!Type.isNull())
    return Type;
  if (ComputeType)
    return ComputeType();
  return QualType();
}

344private:
bool Enabled;
/// Start position of a token for which we store expected type.
SourceLocation ExpectedLoc;
/// Expected type for a token starting at ExpectedLoc.
QualType Type;
/// A function to compute expected type at ExpectedLoc. It is only considered
/// if Type is null.
llvm::function_ref<QualType()> ComputeType;
353};

355/// Sema - This implements semantic analysis and AST building for C.
356class Sema final {
Sema(const Sema &) = delete;
void operator=(const Sema &) = delete;

///Source of additional semantic information.
IntrusiveRefCntPtr<ExternalSemaSource> ExternalSource;

static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);

/// Determine whether two declarations should be linked together, given that
/// the old declaration might not be visible and the new declaration might
/// not have external linkage.
bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
                                  const NamedDecl *New) {
  if (isVisible(Old))
   return true;
  // See comment in below overload for why it's safe to compute the linkage
  // of the new declaration here.
  if (New->isExternallyDeclarable()) {
    assert(Old->isExternallyDeclarable() &&(static_cast <bool> (Old->isExternallyDeclarable() &&
 "should not have found a non-externally-declarable previous decl"
) ? void (0) : __assert_fail ("Old->isExternallyDeclarable() && \"should not have found a non-externally-declarable previous decl\""
, "clang/include/clang/Sema/Sema.h", 376, __extension__ __PRETTY_FUNCTION__
))
           "should not have found a non-externally-declarable previous decl")(static_cast <bool> (Old->isExternallyDeclarable() &&
 "should not have found a non-externally-declarable previous decl"
) ? void (0) : __assert_fail ("Old->isExternallyDeclarable() && \"should not have found a non-externally-declarable previous decl\""
, "clang/include/clang/Sema/Sema.h", 376, __extension__ __PRETTY_FUNCTION__
));
    return true;
  }
  return false;
}
bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);

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

387public:
/// The maximum alignment, same as in llvm::Value. We duplicate them here
/// because that allows us not to duplicate the constants in clang code,
/// which we must to since we can't directly use the llvm constants.
/// The value is verified against llvm here: lib/CodeGen/CGDecl.cpp
///
/// This is the greatest alignment value supported by load, store, and alloca
/// instructions, and global values.
static const unsigned MaxAlignmentExponent = 32;
static const uint64_t MaximumAlignment = 1ull << MaxAlignmentExponent;

typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
typedef OpaquePtr<TemplateName> TemplateTy;
typedef OpaquePtr<QualType> TypeTy;

OpenCLOptions OpenCLFeatures;
FPOptions CurFPFeatures;

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

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

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

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

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

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

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

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

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

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

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

/// pragma clang section kind
enum PragmaClangSectionKind {
  PCSK_Invalid      = 0,
  PCSK_BSS          = 1,
  PCSK_Data         = 2,
  PCSK_Rodata       = 3,
  PCSK_Text         = 4,
  PCSK_Relro        = 5
 };

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

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

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

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

struct PragmaPackInfo {
  PragmaMsStackAction Action;
  StringRef SlotLabel;
  Token Alignment;
};

// #pragma pack and align.
class AlignPackInfo {
public:
  // `Native` represents default align mode, which may vary based on the
  // platform.
  enum Mode : unsigned char { Native, Natural, Packed, Mac68k };

  // #pragma pack info constructor
  AlignPackInfo(AlignPackInfo::Mode M, unsigned Num, bool IsXL)
      : PackAttr(true), AlignMode(M), PackNumber(Num), XLStack(IsXL) {
    assert(Num == PackNumber && "The pack number has been truncated.")(static_cast <bool> (Num == PackNumber && "The pack number has been truncated."
) ? void (0) : __assert_fail ("Num == PackNumber && \"The pack number has been truncated.\""
, "clang/include/clang/Sema/Sema.h", 500, __extension__ __PRETTY_FUNCTION__
));
  }

  // #pragma align info constructor
  AlignPackInfo(AlignPackInfo::Mode M, bool IsXL)
      : PackAttr(false), AlignMode(M),
        PackNumber(M == Packed ? 1 : UninitPackVal), XLStack(IsXL) {}

  explicit AlignPackInfo(bool IsXL) : AlignPackInfo(Native, IsXL) {}

  AlignPackInfo() : AlignPackInfo(Native, false) {}

  // When a AlignPackInfo itself cannot be used, this returns an 32-bit
  // integer encoding for it. This should only be passed to
  // AlignPackInfo::getFromRawEncoding, it should not be inspected directly.
  static uint32_t getRawEncoding(const AlignPackInfo &Info) {
    std::uint32_t Encoding{};
    if (Info.IsXLStack())
      Encoding |= IsXLMask;

    Encoding |= static_cast<uint32_t>(Info.getAlignMode()) << 1;

    if (Info.IsPackAttr())
      Encoding |= PackAttrMask;

    Encoding |= static_cast<uint32_t>(Info.getPackNumber()) << 4;

    return Encoding;
  }

  static AlignPackInfo getFromRawEncoding(unsigned Encoding) {
    bool IsXL = static_cast<bool>(Encoding & IsXLMask);
    AlignPackInfo::Mode M =
        static_cast<AlignPackInfo::Mode>((Encoding & AlignModeMask) >> 1);
    int PackNumber = (Encoding & PackNumMask) >> 4;

    if (Encoding & PackAttrMask)
      return AlignPackInfo(M, PackNumber, IsXL);

    return AlignPackInfo(M, IsXL);
  }

  bool IsPackAttr() const { return PackAttr; }

  bool IsAlignAttr() const { return !PackAttr; }

  Mode getAlignMode() const { return AlignMode; }

  unsigned getPackNumber() const { return PackNumber; }

  bool IsPackSet() const {
    // #pragma align, #pragma pack(), and #pragma pack(0) do not set the pack
    // attriute on a decl.
    return PackNumber != UninitPackVal && PackNumber != 0;
  }

  bool IsXLStack() const { return XLStack; }

  bool operator==(const AlignPackInfo &Info) const {
    return std::tie(AlignMode, PackNumber, PackAttr, XLStack) ==
           std::tie(Info.AlignMode, Info.PackNumber, Info.PackAttr,
                    Info.XLStack);
  }

  bool operator!=(const AlignPackInfo &Info) const {
    return !(*this == Info);
  }

private:
  /// \brief True if this is a pragma pack attribute,
  ///         not a pragma align attribute.
  bool PackAttr;

  /// \brief The alignment mode that is in effect.
  Mode AlignMode;

  /// \brief The pack number of the stack.
  unsigned char PackNumber;

  /// \brief True if it is a XL #pragma align/pack stack.
  bool XLStack;

  /// \brief Uninitialized pack value.
  static constexpr unsigned char UninitPackVal = -1;

  // Masks to encode and decode an AlignPackInfo.
  static constexpr uint32_t IsXLMask{0x0000'0001};
  static constexpr uint32_t AlignModeMask{0x0000'0006};
  static constexpr uint32_t PackAttrMask{0x00000'0008};
  static constexpr uint32_t PackNumMask{0x0000'01F0};
};

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

  void Act(SourceLocation PragmaLocation, PragmaMsStackAction Action,
           llvm::StringRef StackSlotLabel, ValueType Value) {
    if (Action == PSK_Reset) {
      CurrentValue = DefaultValue;
      CurrentPragmaLocation = PragmaLocation;
      return;
    }
    if (Action & PSK_Push)
      Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
                         PragmaLocation);
    else if (Action & PSK_Pop) {
      if (!StackSlotLabel.empty()) {
        // If we've got a label, try to find it and jump there.
        auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
          return x.StackSlotLabel == StackSlotLabel;
        });
        // If we found the label so pop from there.
        if (I != Stack.rend()) {
          CurrentValue = I->Value;
          CurrentPragmaLocation = I->PragmaLocation;
          Stack.erase(std::prev(I.base()), Stack.end());
        }
      } else if (!Stack.empty()) {
        // We do not have a label, just pop the last entry.
        CurrentValue = Stack.back().Value;
        CurrentPragmaLocation = Stack.back().PragmaLocation;
        Stack.pop_back();
      }
    }
    if (Action & PSK_Set) {
      CurrentValue = Value;
      CurrentPragmaLocation = PragmaLocation;
    }
  }

  // MSVC seems to add artificial slots to #pragma stacks on entering a C++
  // method body to restore the stacks on exit, so it works like this:
  //
  //   struct S {
  //     #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
  //     void Method {}
  //     #pragma <name>(pop, InternalPragmaSlot)
  //   };
  //
  // It works even with #pragma vtordisp, although MSVC doesn't support
  //   #pragma vtordisp(push [, id], n)
  // syntax.
  //
  // Push / pop a named sentinel slot.
  void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
    assert((Action == PSK_Push || Action == PSK_Pop) &&(static_cast <bool> ((Action == PSK_Push || Action == PSK_Pop
) && "Can only push / pop #pragma stack sentinels!") ?
 void (0) : __assert_fail ("(Action == PSK_Push || Action == PSK_Pop) && \"Can only push / pop #pragma stack sentinels!\""
, "clang/include/clang/Sema/Sema.h", 657, __extension__ __PRETTY_FUNCTION__
))
           "Can only push / pop #pragma stack sentinels!")(static_cast <bool> ((Action == PSK_Push || Action == PSK_Pop
) && "Can only push / pop #pragma stack sentinels!") ?
 void (0) : __assert_fail ("(Action == PSK_Push || Action == PSK_Pop) && \"Can only push / pop #pragma stack sentinels!\""
, "clang/include/clang/Sema/Sema.h", 657, __extension__ __PRETTY_FUNCTION__
));
    Act(CurrentPragmaLocation, Action, Label, CurrentValue);
  }

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

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

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

/// Whether to insert vtordisps prior to virtual bases in the Microsoft
/// C++ ABI.  Possible values are 0, 1, and 2, which mean:
///
/// 0: Suppress all vtordisps
/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
///    structors
/// 2: Always insert vtordisps to support RTTI on partially constructed
///    objects
PragmaStack<MSVtorDispMode> VtorDispStack;
PragmaStack<AlignPackInfo> AlignPackStack;
// The current #pragma align/pack values and locations at each #include.
struct AlignPackIncludeState {
  AlignPackInfo CurrentValue;
  SourceLocation CurrentPragmaLocation;
  bool HasNonDefaultValue, ShouldWarnOnInclude;
};
SmallVector<AlignPackIncludeState, 8> AlignPackIncludeStack;
// Segment #pragmas.
PragmaStack<StringLiteral *> DataSegStack;
PragmaStack<StringLiteral *> BSSSegStack;
PragmaStack<StringLiteral *> ConstSegStack;
PragmaStack<StringLiteral *> CodeSegStack;

// #pragma strict_gs_check.
PragmaStack<bool> StrictGuardStackCheckStack;

// This stack tracks the current state of Sema.CurFPFeatures.
PragmaStack<FPOptionsOverride> FpPragmaStack;
FPOptionsOverride CurFPFeatureOverrides() {
  FPOptionsOverride result;
  if (!FpPragmaStack.hasValue()) {
    result = FPOptionsOverride();
  } else {
    result = FpPragmaStack.CurrentValue;
  }
  return result;
}

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

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

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

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

/// Sections used with #pragma alloc_text.
llvm::StringMap<std::tuple<StringRef, SourceLocation>> FunctionToSectionMap;

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

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

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

SmallVector<PragmaAttributeGroup, 2> PragmaAttributeStack;

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

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

/// The "on" or "off" argument passed by \#pragma optimize, that denotes
/// whether the optimizations in the list passed to the pragma should be
/// turned off or on. This boolean is true by default because command line
/// options are honored when `#pragma optimize("", on)`.
/// (i.e. `ModifyFnAttributeMSPragmaOptimze()` does nothing)
bool MSPragmaOptimizeIsOn = true;

/// Set of no-builtin functions listed by \#pragma function.
llvm::SmallSetVector<StringRef, 4> MSFunctionNoBuiltins;

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

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

/// ExprCleanupObjects - This is the stack of objects requiring
/// cleanup that are created by the current full expression.
SmallVector<ExprWithCleanups::CleanupObject, 8> ExprCleanupObjects;

/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
/// to a variable (constant) that may or may not be odr-used in this Expr, and
/// we won't know until all lvalue-to-rvalue and discarded value conversions
/// have been applied to all subexpressions of the enclosing full expression.
/// This is cleared at the end of each full expression.
using MaybeODRUseExprSet = llvm::SetVector<Expr *, SmallVector<Expr *, 4>,
                                           llvm::SmallPtrSet<Expr *, 4>>;
MaybeODRUseExprSet MaybeODRUseExprs;

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

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

/// The index of the first FunctionScope that corresponds to the current
/// context.
unsigned FunctionScopesStart = 0;

ArrayRef<sema::FunctionScopeInfo*> getFunctionScopes() const {
  return llvm::ArrayRef(FunctionScopes.begin() + FunctionScopesStart,
                        FunctionScopes.end());
}

/// Stack containing information needed when in C++2a an 'auto' is encountered
/// in a function declaration parameter type specifier in order to invent a
/// corresponding template parameter in the enclosing abbreviated function
/// template. This information is also present in LambdaScopeInfo, stored in
/// the FunctionScopes stack.
SmallVector<InventedTemplateParameterInfo, 4> InventedParameterInfos;

/// The index of the first InventedParameterInfo that refers to the current
/// context.
unsigned InventedParameterInfosStart = 0;

ArrayRef<InventedTemplateParameterInfo> getInventedParameterInfos() const {
  return llvm::ArrayRef(InventedParameterInfos.begin() +
                            InventedParameterInfosStart,
                        InventedParameterInfos.end());
}

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

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

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

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

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

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

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

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

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

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

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

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

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

/// All the external declarations encoutered and used in the TU.
SmallVector<VarDecl *, 4> ExternalDeclarations;

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

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

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

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

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

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

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

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

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

class DelayedDiagnostics;

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

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

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

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

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

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

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

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

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

  /// Undo a previous pushUndelayed().
  void popUndelayed(DelayedDiagnosticsState state) {
    assert(CurPool == nullptr)(static_cast <bool> (CurPool == nullptr) ? void (0) : __assert_fail
 ("CurPool == nullptr", "clang/include/clang/Sema/Sema.h", 992
, __extension__ __PRETTY_FUNCTION__));
    CurPool = state.SavedPool;
  }
} DelayedDiagnostics;

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

public:
  ContextRAII(Sema &S, DeclContext *ContextToPush, bool NewThisContext = true)
    : S(S), SavedContext(S.CurContext),
      SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
      SavedCXXThisTypeOverride(S.CXXThisTypeOverride),
      SavedFunctionScopesStart(S.FunctionScopesStart),
      SavedInventedParameterInfosStart(S.InventedParameterInfosStart)
  {
    assert(ContextToPush && "pushing null context")(static_cast <bool> (ContextToPush && "pushing null context"
) ? void (0) : __assert_fail ("ContextToPush && \"pushing null context\""
, "clang/include/clang/Sema/Sema.h", 1015, __extension__ __PRETTY_FUNCTION__
));
    S.CurContext = ContextToPush;
    if (NewThisContext)
      S.CXXThisTypeOverride = QualType();
    // Any saved FunctionScopes do not refer to this context.
    S.FunctionScopesStart = S.FunctionScopes.size();
    S.InventedParameterInfosStart = S.InventedParameterInfos.size();
  }

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

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

/// Whether the AST is currently being rebuilt to correct immediate
/// invocations. Immediate invocation candidates and references to consteval
/// functions aren't tracked when this is set.
bool RebuildingImmediateInvocation = false;

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

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

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

public:
  SynthesizedFunctionScope(Sema &S, DeclContext *DC)
      : S(S), SavedContext(S, DC) {
    S.PushFunctionScope();
    S.PushExpressionEvaluationContext(
        Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
    if (auto *FD = dyn_cast<FunctionDecl>(DC))
      FD->setWillHaveBody(true);
    else
      assert(isa<ObjCMethodDecl>(DC))(static_cast <bool> (isa<ObjCMethodDecl>(DC)) ? void
 (0) : __assert_fail ("isa<ObjCMethodDecl>(DC)", "clang/include/clang/Sema/Sema.h"
, 1069, __extension__ __PRETTY_FUNCTION__));
  }

  void addContextNote(SourceLocation UseLoc) {
    assert(!PushedCodeSynthesisContext)(static_cast <bool> (!PushedCodeSynthesisContext) ? void
 (0) : __assert_fail ("!PushedCodeSynthesisContext", "clang/include/clang/Sema/Sema.h"
, 1073, __extension__ __PRETTY_FUNCTION__));

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

    PushedCodeSynthesisContext = true;
  }

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

/// WeakUndeclaredIdentifiers - Identifiers contained in \#pragma weak before
/// declared. Rare. May alias another identifier, declared or undeclared.
///
/// For aliases, the target identifier is used as a key for eventual
/// processing when the target is declared. For the single-identifier form,
/// the sole identifier is used as the key. Each entry is a `SetVector`
/// (ordered by parse order) of aliases (identified by the alias name) in case
/// of multiple aliases to the same undeclared identifier.
llvm::MapVector<
    IdentifierInfo *,
    llvm::SetVector<
        WeakInfo, llvm::SmallVector<WeakInfo, 1u>,
        llvm::SmallDenseSet<WeakInfo, 2u, WeakInfo::DenseMapInfoByAliasOnly>>>
    WeakUndeclaredIdentifiers;

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


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

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

IdentifierResolver IdResolver;

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

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

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

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

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

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

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

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

/// The C++ "std::source_location::__impl" struct, defined in
/// \<source_location>.
RecordDecl *StdSourceLocationImplDecl;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  /// In addition of being constant evaluated, the current expression
  /// occurs in an immediate function context - either a consteval function
  /// or a consteval if function.
  ImmediateFunctionContext,

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

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

using ImmediateInvocationCandidate = llvm::PointerIntPair<ConstantExpr *, 1>;

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

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

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

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

  MaybeODRUseExprSet SavedMaybeODRUseExprs;

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

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

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

  /// If we are processing a decltype type, a set of temporary binding
  /// expressions for which we have deferred checking the destructor.
  SmallVector<CXXBindTemporaryExpr *, 8> DelayedDecltypeBinds;

  llvm::SmallPtrSet<const Expr *, 8> PossibleDerefs;

  /// Expressions appearing as the LHS of a volatile assignment in this
  /// context. We produce a warning for these when popping the context if
  /// they are not discarded-value expressions nor unevaluated operands.
  SmallVector<Expr*, 2> VolatileAssignmentLHSs;

  /// Set of candidates for starting an immediate invocation.
  llvm::SmallVector<ImmediateInvocationCandidate, 4> ImmediateInvocationCandidates;

  /// Set of DeclRefExprs referencing a consteval function when used in a
  /// context not already known to be immediately invoked.
  llvm::SmallPtrSet<DeclRefExpr *, 4> ReferenceToConsteval;

  /// \brief Describes whether we are in an expression constext which we have
  /// to handle differently.
  enum ExpressionKind {
    EK_Decltype, EK_TemplateArgument, EK_Other
  } ExprContext;

  // A context can be nested in both a discarded statement context and
  // an immediate function context, so they need to be tracked independently.
  bool InDiscardedStatement;
  bool InImmediateFunctionContext;

  bool IsCurrentlyCheckingDefaultArgumentOrInitializer = false;

  // When evaluating immediate functions in the initializer of a default
  // argument or default member initializer, this is the declaration whose
  // default initializer is being evaluated and the location of the call
  // or constructor definition.
  struct InitializationContext {
    InitializationContext(SourceLocation Loc, ValueDecl *Decl,
                          DeclContext *Context)
        : Loc(Loc), Decl(Decl), Context(Context) {
      assert(Decl && Context && "invalid initialization context")(static_cast <bool> (Decl && Context &&
 "invalid initialization context") ? void (0) : __assert_fail
 ("Decl && Context && \"invalid initialization context\""
, "clang/include/clang/Sema/Sema.h", 1339, __extension__ __PRETTY_FUNCTION__
));
    }

    SourceLocation Loc;
    ValueDecl *Decl = nullptr;
    DeclContext *Context = nullptr;
  };
  std::optional<InitializationContext> DelayedDefaultInitializationContext;

  ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
                                    unsigned NumCleanupObjects,
                                    CleanupInfo ParentCleanup,
                                    Decl *ManglingContextDecl,
                                    ExpressionKind ExprContext)
      : Context(Context), ParentCleanup(ParentCleanup),
        NumCleanupObjects(NumCleanupObjects), NumTypos(0),
        ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext),
        InDiscardedStatement(false), InImmediateFunctionContext(false) {}

  bool isUnevaluated() const {
    return Context == ExpressionEvaluationContext::Unevaluated ||
           Context == ExpressionEvaluationContext::UnevaluatedAbstract ||
           Context == ExpressionEvaluationContext::UnevaluatedList;
  }

  bool isConstantEvaluated() const {
    return Context == ExpressionEvaluationContext::ConstantEvaluated ||
           Context == ExpressionEvaluationContext::ImmediateFunctionContext;
  }

  bool isImmediateFunctionContext() const {
    return Context == ExpressionEvaluationContext::ImmediateFunctionContext ||
           (Context == ExpressionEvaluationContext::DiscardedStatement &&
            InImmediateFunctionContext) ||
           // C++2b [expr.const]p14:
           // An expression or conversion is in an immediate function
           // context if it is potentially evaluated and either:
           //   * its innermost enclosing non-block scope is a function
           //     parameter scope of an immediate function, or
           //   * its enclosing statement is enclosed by the compound-
           //     statement of a consteval if statement.
           (Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
            InImmediateFunctionContext);
  }

  bool isDiscardedStatementContext() const {
    return Context == ExpressionEvaluationContext::DiscardedStatement ||
           (Context ==
                ExpressionEvaluationContext::ImmediateFunctionContext &&
            InDiscardedStatement);
  }
};

/// A stack of expression evaluation contexts.
SmallVector<ExpressionEvaluationContextRecord, 8> ExprEvalContexts;

/// Emit a warning for all pending noderef expressions that we recorded.
void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);

/// Compute the mangling number context for a lambda expression or
/// block literal. Also return the extra mangling decl if any.
///
/// \param DC - The DeclContext containing the lambda expression or
/// block literal.
std::tuple<MangleNumberingContext *, Decl *>
getCurrentMangleNumberContext(const DeclContext *DC);


/// SpecialMemberOverloadResult - The overloading result for a special member
/// function.
///
/// This is basically a wrapper around PointerIntPair. The lowest bits of the
/// integer are used to determine whether overload resolution succeeded.
class SpecialMemberOverloadResult {
public:
  enum Kind {
    NoMemberOrDeleted,
    Ambiguous,
    Success
  };

private:
  llvm::PointerIntPair<CXXMethodDecl *, 2> Pair;

public:
  SpecialMemberOverloadResult() {}
  SpecialMemberOverloadResult(CXXMethodDecl *MD)
      : Pair(MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}

  CXXMethodDecl *getMethod() const { return Pair.getPointer(); }
  void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }

  Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
  void setKind(Kind K) { Pair.setInt(K); }
};

class SpecialMemberOverloadResultEntry
    : public llvm::FastFoldingSetNode,
      public SpecialMemberOverloadResult {
public:
  SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
    : FastFoldingSetNode(ID)
  {}
};

/// A cache of special member function overload resolution results
/// for C++ records.
llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;

/// A cache of the flags available in enumerations with the flag_bits
/// attribute.
mutable llvm::DenseMap<const EnumDecl*, llvm::APInt> FlagBitsCache;

/// The kind of translation unit we are processing.
///
/// When we're processing a complete translation unit, Sema will perform
/// end-of-translation-unit semantic tasks (such as creating
/// initializers for tentative definitions in C) once parsing has
/// completed. Modules and precompiled headers perform different kinds of
/// checks.
const TranslationUnitKind TUKind;

llvm::BumpPtrAllocator BumpAlloc;

/// The number of SFINAE diagnostics that have been trapped.
unsigned NumSFINAEErrors;

typedef llvm::DenseMap<ParmVarDecl *, llvm::TinyPtrVector<ParmVarDecl *>>
  UnparsedDefaultArgInstantiationsMap;

/// A mapping from parameters with unparsed default arguments to the
/// set of instantiations of each parameter.
///
/// This mapping is a temporary data structure used when parsing
/// nested class templates or nested classes of class templates,
/// where we might end up instantiating an inner class before the
/// default arguments of its methods have been parsed.
UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;

// Contains the locations of the beginning of unparsed default
// argument locations.
llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;

/// UndefinedInternals - all the used, undefined objects which require a
/// definition in this translation unit.
llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;

/// Determine if VD, which must be a variable or function, is an external
/// symbol that nonetheless can't be referenced from outside this translation
/// unit because its type has no linkage and it's not extern "C".
bool isExternalWithNoLinkageType(ValueDecl *VD) const;

/// Obtain a sorted list of functions that are undefined but ODR-used.
void getUndefinedButUsed(
    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined);

/// Retrieves list of suspicious delete-expressions that will be checked at
/// the end of translation unit.
const llvm::MapVector<FieldDecl *, DeleteLocs> &
getMismatchingDeleteExpressions() const;

class GlobalMethodPool {
public:
  using Lists = std::pair<ObjCMethodList, ObjCMethodList>;
  using iterator = llvm::DenseMap<Selector, Lists>::iterator;
  iterator begin() { return Methods.begin(); }
  iterator end() { return Methods.end(); }
  iterator find(Selector Sel) { return Methods.find(Sel); }
  std::pair<iterator, bool> insert(std::pair<Selector, Lists> &&Val) {
    return Methods.insert(Val);
  }
  int count(Selector Sel) const { return Methods.count(Sel); }
  bool empty() const { return Methods.empty(); }

private:
  llvm::DenseMap<Selector, Lists> Methods;
};

/// Method Pool - allows efficient lookup when typechecking messages to "id".
/// We need to maintain a list, since selectors can have differing signatures
/// across classes. In Cocoa, this happens to be extremely uncommon (only 1%
/// of selectors are "overloaded").
/// At the head of the list it is recorded whether there were 0, 1, or >= 2
/// methods inside categories with a particular selector.
GlobalMethodPool MethodPool;

/// Method selectors used in a \@selector expression. Used for implementation
/// of -Wselector.
llvm::MapVector<Selector, SourceLocation> ReferencedSelectors;

/// List of SourceLocations where 'self' is implicitly retained inside a
/// block.
llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, 1>
    ImplicitlyRetainedSelfLocs;

/// Kinds of C++ special members.
enum CXXSpecialMember {
  CXXDefaultConstructor,
  CXXCopyConstructor,
  CXXMoveConstructor,
  CXXCopyAssignment,
  CXXMoveAssignment,
  CXXDestructor,
  CXXInvalid
};

typedef llvm::PointerIntPair<CXXRecordDecl *, 3, CXXSpecialMember>
    SpecialMemberDecl;

/// The C++ special members which we are currently in the process of
/// declaring. If this process recursively triggers the declaration of the
/// same special member, we should act as if it is not yet declared.
llvm::SmallPtrSet<SpecialMemberDecl, 4> SpecialMembersBeingDeclared;

/// Kinds of defaulted comparison operator functions.
enum class DefaultedComparisonKind : unsigned char {
  /// This is not a defaultable comparison operator.
  None,
  /// This is an operator== that should be implemented as a series of
  /// subobject comparisons.
  Equal,
  /// This is an operator<=> that should be implemented as a series of
  /// subobject comparisons.
  ThreeWay,
  /// This is an operator!= that should be implemented as a rewrite in terms
  /// of a == comparison.
  NotEqual,
  /// This is an <, <=, >, or >= that should be implemented as a rewrite in
  /// terms of a <=> comparison.
  Relational,
};

/// The function definitions which were renamed as part of typo-correction
/// to match their respective declarations. We want to keep track of them
/// to ensure that we don't emit a "redefinition" error if we encounter a
/// correctly named definition after the renamed definition.
llvm::SmallPtrSet<const NamedDecl *, 4> TypoCorrectedFunctionDefinitions;

/// Stack of types that correspond to the parameter entities that are
/// currently being copy-initialized. Can be empty.
llvm::SmallVector<QualType, 4> CurrentParameterCopyTypes;

void ReadMethodPool(Selector Sel);
void updateOutOfDateSelector(Selector Sel);

/// Private Helper predicate to check for 'self'.
bool isSelfExpr(Expr *RExpr);
bool isSelfExpr(Expr *RExpr, const ObjCMethodDecl *Method);

/// Cause the active diagnostic on the DiagosticsEngine to be
/// emitted. This is closely coupled to the SemaDiagnosticBuilder class and
/// should not be used elsewhere.
void EmitCurrentDiagnostic(unsigned DiagID);

/// Records and restores the CurFPFeatures state on entry/exit of compound
/// statements.
class FPFeaturesStateRAII {
public:
  FPFeaturesStateRAII(Sema &S);
  ~FPFeaturesStateRAII();
  FPOptionsOverride getOverrides() { return OldOverrides; }

private:
  Sema& S;
  FPOptions OldFPFeaturesState;
  FPOptionsOverride OldOverrides;
  LangOptions::FPEvalMethodKind OldEvalMethod;
  SourceLocation OldFPPragmaLocation;
};

void addImplicitTypedef(StringRef Name, QualType T);

bool WarnedStackExhausted = false;

/// Increment when we find a reference; decrement when we find an ignored
/// assignment.  Ultimately the value is 0 if every reference is an ignored
/// assignment.
llvm::DenseMap<const VarDecl *, int> RefsMinusAssignments;

/// Indicate RISC-V vector builtin functions enabled or not.
bool DeclareRISCVVBuiltins = false;

1621private:
std::unique_ptr<sema::RISCVIntrinsicManager> RVIntrinsicManager;

std::optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;

bool WarnedDarwinSDKInfoMissing = false;

1628public:
Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     TranslationUnitKind TUKind = TU_Complete,
     CodeCompleteConsumer *CompletionConsumer = nullptr);
~Sema();

/// Perform initialization that occurs after the parser has been
/// initialized but before it parses anything.
void Initialize();

/// This virtual key function only exists to limit the emission of debug info
/// describing the Sema class. GCC and Clang only emit debug info for a class
/// with a vtable when the vtable is emitted. Sema is final and not
/// polymorphic, but the debug info size savings are so significant that it is
/// worth adding a vtable just to take advantage of this optimization.
virtual void anchor();

const LangOptions &getLangOpts() const { return LangOpts; }
OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
FPOptions     &getCurFPFeatures() { return CurFPFeatures; }

DiagnosticsEngine &getDiagnostics() const { return Diags; }
SourceManager &getSourceManager() const { return SourceMgr; }
Preprocessor &getPreprocessor() const { return PP; }
ASTContext &getASTContext() const { return Context; }
ASTConsumer &getASTConsumer() const { return Consumer; }
ASTMutationListener *getASTMutationListener() const;
ExternalSemaSource *getExternalSource() const { return ExternalSource.get(); }

DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking(SourceLocation Loc,
                                                       StringRef Platform);
DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking();

///Registers an external source. If an external source already exists,
/// creates a multiplex external source and appends to it.
///
///\param[in] E - A non-null external sema source.
///
void addExternalSource(ExternalSemaSource *E);

void PrintStats() const;

/// Warn that the stack is nearly exhausted.
void warnStackExhausted(SourceLocation Loc);

/// Run some code with "sufficient" stack space. (Currently, at least 256K is
/// guaranteed). Produces a warning if we're low on stack space and allocates
/// more in that case. Use this in code that may recurse deeply (for example,
/// in template instantiation) to avoid stack overflow.
void runWithSufficientStackSpace(SourceLocation Loc,
                                 llvm::function_ref<void()> Fn);

/// Helper class that creates diagnostics with optional
/// template instantiation stacks.
///
/// This class provides a wrapper around the basic DiagnosticBuilder
/// class that emits diagnostics. ImmediateDiagBuilder is
/// responsible for emitting the diagnostic (as DiagnosticBuilder
/// does) and, if the diagnostic comes from inside a template
/// instantiation, printing the template instantiation stack as
/// well.
class ImmediateDiagBuilder : public DiagnosticBuilder {
  Sema &SemaRef;
  unsigned DiagID;

public:
  ImmediateDiagBuilder(DiagnosticBuilder &DB, Sema &SemaRef, unsigned DiagID)
      : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}
  ImmediateDiagBuilder(DiagnosticBuilder &&DB, Sema &SemaRef, unsigned DiagID)
      : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}

  // This is a cunning lie. DiagnosticBuilder actually performs move
  // construction in its copy constructor (but due to varied uses, it's not
  // possible to conveniently express this as actual move construction). So
  // the default copy ctor here is fine, because the base class disables the
  // source anyway, so the user-defined ~ImmediateDiagBuilder is a safe no-op
  // in that case anwyay.
  ImmediateDiagBuilder(const ImmediateDiagBuilder &) = default;

  ~ImmediateDiagBuilder() {
    // If we aren't active, there is nothing to do.
    if (!isActive()) return;

    // Otherwise, we need to emit the diagnostic. First clear the diagnostic
    // builder itself so it won't emit the diagnostic in its own destructor.
    //
    // This seems wasteful, in that as written the DiagnosticBuilder dtor will
    // do its own needless checks to see if the diagnostic needs to be
    // emitted. However, because we take care to ensure that the builder
    // objects never escape, a sufficiently smart compiler will be able to
    // eliminate that code.
    Clear();

    // Dispatch to Sema to emit the diagnostic.
    SemaRef.EmitCurrentDiagnostic(DiagID);
  }

  /// Teach operator<< to produce an object of the correct type.
  template <typename T>
  friend const ImmediateDiagBuilder &
  operator<<(const ImmediateDiagBuilder &Diag, const T &Value) {
    const DiagnosticBuilder &BaseDiag = Diag;
    BaseDiag << Value;
    return Diag;
  }

  // It is necessary to limit this to rvalue reference to avoid calling this
  // function with a bitfield lvalue argument since non-const reference to
  // bitfield is not allowed.
  template <typename T,
            typename = std::enable_if_t<!std::is_lvalue_reference<T>::value>>
  const ImmediateDiagBuilder &operator<<(T &&V) const {
    const DiagnosticBuilder &BaseDiag = *this;
    BaseDiag << std::move(V);
    return *this;
  }
};

/// A generic diagnostic builder for errors which may or may not be deferred.
///
/// In CUDA, there exist constructs (e.g. variable-length arrays, try/catch)
/// which are not allowed to appear inside __device__ functions and are
/// allowed to appear in __host__ __device__ functions only if the host+device
/// function is never codegen'ed.
///
/// To handle this, we use the notion of "deferred diagnostics", where we
/// attach a diagnostic to a FunctionDecl that's emitted iff it's codegen'ed.
///
/// This class lets you emit either a regular diagnostic, a deferred
/// diagnostic, or no diagnostic at all, according to an argument you pass to
/// its constructor, thus simplifying the process of creating these "maybe
/// deferred" diagnostics.
class SemaDiagnosticBuilder {
public:
  enum Kind {
    /// Emit no diagnostics.
    K_Nop,
    /// Emit the diagnostic immediately (i.e., behave like Sema::Diag()).
    K_Immediate,
    /// Emit the diagnostic immediately, and, if it's a warning or error, also
    /// emit a call stack showing how this function can be reached by an a
    /// priori known-emitted function.
    K_ImmediateWithCallStack,
    /// Create a deferred diagnostic, which is emitted only if the function
    /// it's attached to is codegen'ed.  Also emit a call stack as with
    /// K_ImmediateWithCallStack.
    K_Deferred
  };

  SemaDiagnosticBuilder(Kind K, SourceLocation Loc, unsigned DiagID,
                        FunctionDecl *Fn, Sema &S);
  SemaDiagnosticBuilder(SemaDiagnosticBuilder &&D);
  SemaDiagnosticBuilder(const SemaDiagnosticBuilder &) = default;
  ~SemaDiagnosticBuilder();

  bool isImmediate() const { return ImmediateDiag.has_value(); }

  /// Convertible to bool: True if we immediately emitted an error, false if
  /// we didn't emit an error or we created a deferred error.
  ///
  /// Example usage:
  ///
  ///   if (SemaDiagnosticBuilder(...) << foo << bar)
  ///     return ExprError();
  ///
  /// But see CUDADiagIfDeviceCode() and CUDADiagIfHostCode() -- you probably
  /// want to use these instead of creating a SemaDiagnosticBuilder yourself.
  operator bool() const { return isImmediate(); }

  template <typename T>
  friend const SemaDiagnosticBuilder &
  operator<<(const SemaDiagnosticBuilder &Diag, const T &Value) {
    if (Diag.ImmediateDiag)
      *Diag.ImmediateDiag << Value;
    else if (Diag.PartialDiagId)
      Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second
          << Value;
    return Diag;
  }

  // It is necessary to limit this to rvalue reference to avoid calling this
  // function with a bitfield lvalue argument since non-const reference to
  // bitfield is not allowed.
  template <typename T,
            typename = std::enable_if_t<!std::is_lvalue_reference<T>::value>>
  const SemaDiagnosticBuilder &operator<<(T &&V) const {
    if (ImmediateDiag)
      *ImmediateDiag << std::move(V);
    else if (PartialDiagId)
      S.DeviceDeferredDiags[Fn][*PartialDiagId].second << std::move(V);
    return *this;
  }

  friend const SemaDiagnosticBuilder &
  operator<<(const SemaDiagnosticBuilder &Diag, const PartialDiagnostic &PD) {
    if (Diag.ImmediateDiag)
      PD.Emit(*Diag.ImmediateDiag);
    else if (Diag.PartialDiagId)
      Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second = PD;
    return Diag;
  }

  void AddFixItHint(const FixItHint &Hint) const {
    if (ImmediateDiag)
      ImmediateDiag->AddFixItHint(Hint);
    else if (PartialDiagId)
      S.DeviceDeferredDiags[Fn][*PartialDiagId].second.AddFixItHint(Hint);
  }

  friend ExprResult ExprError(const SemaDiagnosticBuilder &) {
    return ExprError();
  }
  friend StmtResult StmtError(const SemaDiagnosticBuilder &) {
    return StmtError();
  }
  operator ExprResult() const { return ExprError(); }
  operator StmtResult() const { return StmtError(); }
  operator TypeResult() const { return TypeError(); }
  operator DeclResult() const { return DeclResult(true); }
  operator MemInitResult() const { return MemInitResult(true); }

private:
  Sema &S;
  SourceLocation Loc;
  unsigned DiagID;
  FunctionDecl *Fn;
  bool ShowCallStack;

  // Invariant: At most one of these Optionals has a value.
  // FIXME: Switch these to a Variant once that exists.
  std::optional<ImmediateDiagBuilder> ImmediateDiag;
  std::optional<unsigned> PartialDiagId;
};

/// Is the last error level diagnostic immediate. This is used to determined
/// whether the next info diagnostic should be immediate.
bool IsLastErrorImmediate = true;

/// Emit a diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID,
                           bool DeferHint = false);

/// Emit a partial diagnostic.
SemaDiagnosticBuilder Diag(SourceLocation Loc, const PartialDiagnostic &PD,
                           bool DeferHint = false);

/// Build a partial diagnostic.
PartialDiagnostic PDiag(unsigned DiagID = 0); // in SemaInternal.h

/// Whether deferrable diagnostics should be deferred.
bool DeferDiags = false;

/// RAII class to control scope of DeferDiags.
class DeferDiagsRAII {
  Sema &S;
  bool SavedDeferDiags = false;

public:
  DeferDiagsRAII(Sema &S, bool DeferDiags)
      : S(S), SavedDeferDiags(S.DeferDiags) {
    S.DeferDiags = DeferDiags;
  }
  ~DeferDiagsRAII() { S.DeferDiags = SavedDeferDiags; }
};

/// Whether uncompilable error has occurred. This includes error happens
/// in deferred diagnostics.
bool hasUncompilableErrorOccurred() const;

bool findMacroSpelling(SourceLocation &loc, StringRef name);

/// Get a string to suggest for zero-initialization of a type.
std::string
getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const;
std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;

/// Calls \c Lexer::getLocForEndOfToken()
SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = 0);

/// Retrieve the module loader associated with the preprocessor.
ModuleLoader &getModuleLoader() const;

/// Invent a new identifier for parameters of abbreviated templates.
IdentifierInfo *
InventAbbreviatedTemplateParameterTypeName(IdentifierInfo *ParamName,
                                           unsigned Index);

void emitAndClearUnusedLocalTypedefWarnings();

private:
  /// Function or variable declarations to be checked for whether the deferred
  /// diagnostics should be emitted.
  llvm::SmallSetVector<Decl *, 4> DeclsToCheckForDeferredDiags;

public:
// Emit all deferred diagnostics.
void emitDeferredDiags();

enum TUFragmentKind {
  /// The global module fragment, between 'module;' and a module-declaration.
  Global,
  /// A normal translation unit fragment. For a non-module unit, this is the
  /// entire translation unit. Otherwise, it runs from the module-declaration
  /// to the private-module-fragment (if any) or the end of the TU (if not).
  Normal,
  /// The private module fragment, between 'module :private;' and the end of
  /// the translation unit.
  Private
};

void ActOnStartOfTranslationUnit();
void ActOnEndOfTranslationUnit();
void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);

void CheckDelegatingCtorCycles();

Scope *getScopeForContext(DeclContext *Ctx);

void PushFunctionScope();
void PushBlockScope(Scope *BlockScope, BlockDecl *Block);
sema::LambdaScopeInfo *PushLambdaScope();

/// This is used to inform Sema what the current TemplateParameterDepth
/// is during Parsing.  Currently it is used to pass on the depth
/// when parsing generic lambda 'auto' parameters.
void RecordParsingTemplateParameterDepth(unsigned Depth);

void PushCapturedRegionScope(Scope *RegionScope, CapturedDecl *CD,
                             RecordDecl *RD, CapturedRegionKind K,
                             unsigned OpenMPCaptureLevel = 0);

/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
/// time after they've been popped.
class PoppedFunctionScopeDeleter {
  Sema *Self;

public:
  explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
  void operator()(sema::FunctionScopeInfo *Scope) const;
};

using PoppedFunctionScopePtr =
    std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;

PoppedFunctionScopePtr
PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy *WP = nullptr,
                     const Decl *D = nullptr,
                     QualType BlockType = QualType());

sema::FunctionScopeInfo *getCurFunction() const {
  return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
13
←
'?' condition is false→
14
←
Returning pointer, which participates in a condition later→
}

sema::FunctionScopeInfo *getEnclosingFunction() const;

void setFunctionHasBranchIntoScope();
void setFunctionHasBranchProtectedScope();
void setFunctionHasIndirectGoto();
void setFunctionHasMustTail();

void PushCompoundScope(bool IsStmtExpr);
void PopCompoundScope();

sema::CompoundScopeInfo &getCurCompoundScope() const;

bool hasAnyUnrecoverableErrorsInThisFunction() const;

/// Retrieve the current block, if any.
sema::BlockScopeInfo *getCurBlock();

/// Get the innermost lambda enclosing the current location, if any. This
/// looks through intervening non-lambda scopes such as local functions and
/// blocks.
sema::LambdaScopeInfo *getEnclosingLambda() const;

/// Retrieve the current lambda scope info, if any.
/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
/// lambda scope info ignoring all inner capturing scopes that are not
/// lambda scopes.
sema::LambdaScopeInfo *
getCurLambda(bool IgnoreNonLambdaCapturingScope = false);

/// Retrieve the current generic lambda info, if any.
sema::LambdaScopeInfo *getCurGenericLambda();

/// Retrieve the current captured region, if any.
sema::CapturedRegionScopeInfo *getCurCapturedRegion();

/// Retrieve the current function, if any, that should be analyzed for
/// potential availability violations.
sema::FunctionScopeInfo *getCurFunctionAvailabilityContext();

/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
SmallVectorImpl<Decl *> &WeakTopLevelDecls() { return WeakTopLevelDecl; }

/// Called before parsing a function declarator belonging to a function
/// declaration.
void ActOnStartFunctionDeclarationDeclarator(Declarator &D,
                                             unsigned TemplateParameterDepth);

/// Called after parsing a function declarator belonging to a function
/// declaration.
void ActOnFinishFunctionDeclarationDeclarator(Declarator &D);

void ActOnComment(SourceRange Comment);

//===--------------------------------------------------------------------===//
// Type Analysis / Processing: SemaType.cpp.
//

QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
                            const DeclSpec *DS = nullptr);
QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
                            const DeclSpec *DS = nullptr);
QualType BuildPointerType(QualType T,
                          SourceLocation Loc, DeclarationName Entity);
QualType BuildReferenceType(QualType T, bool LValueRef,
                            SourceLocation Loc, DeclarationName Entity);
QualType BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
                        Expr *ArraySize, unsigned Quals,
                        SourceRange Brackets, DeclarationName Entity);
QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
QualType BuildExtVectorType(QualType T, Expr *ArraySize,
                            SourceLocation AttrLoc);
QualType BuildMatrixType(QualType T, Expr *NumRows, Expr *NumColumns,
                         SourceLocation AttrLoc);

QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
                               SourceLocation AttrLoc);

/// Same as above, but constructs the AddressSpace index if not provided.
QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
                               SourceLocation AttrLoc);

bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);

bool CheckFunctionReturnType(QualType T, SourceLocation Loc);

/// Build a function type.
///
/// This routine checks the function type according to C++ rules and
/// under the assumption that the result type and parameter types have
/// just been instantiated from a template. It therefore duplicates
/// some of the behavior of GetTypeForDeclarator, but in a much
/// simpler form that is only suitable for this narrow use case.
///
/// \param T The return type of the function.
///
/// \param ParamTypes The parameter types of the function. This array
/// will be modified to account for adjustments to the types of the
/// function parameters.
///
/// \param Loc The location of the entity whose type involves this
/// function type or, if there is no such entity, the location of the
/// type that will have function type.
///
/// \param Entity The name of the entity that involves the function
/// type, if known.
///
/// \param EPI Extra information about the function type. Usually this will
/// be taken from an existing function with the same prototype.
///
/// \returns A suitable function type, if there are no errors. The
/// unqualified type will always be a FunctionProtoType.
/// Otherwise, returns a NULL type.
QualType BuildFunctionType(QualType T,
                           MutableArrayRef<QualType> ParamTypes,
                           SourceLocation Loc, DeclarationName Entity,
                           const FunctionProtoType::ExtProtoInfo &EPI);

QualType BuildMemberPointerType(QualType T, QualType Class,
                                SourceLocation Loc,
                                DeclarationName Entity);
QualType BuildBlockPointerType(QualType T,
                               SourceLocation Loc, DeclarationName Entity);
QualType BuildParenType(QualType T);
QualType BuildAtomicType(QualType T, SourceLocation Loc);
QualType BuildReadPipeType(QualType T,
                       SourceLocation Loc);
QualType BuildWritePipeType(QualType T,
                       SourceLocation Loc);
QualType BuildBitIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);

TypeSourceInfo *GetTypeForDeclarator(Declarator &D, Scope *S);
TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);

/// Package the given type and TSI into a ParsedType.
ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
DeclarationNameInfo GetNameForDeclarator(Declarator &D);
DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
static QualType GetTypeFromParser(ParsedType Ty,
                                  TypeSourceInfo **TInfo = nullptr);
CanThrowResult canThrow(const Stmt *E);
/// Determine whether the callee of a particular function call can throw.
/// E, D and Loc are all optional.
static CanThrowResult canCalleeThrow(Sema &S, const Expr *E, const Decl *D,
                                     SourceLocation Loc = SourceLocation());
const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
                                              const FunctionProtoType *FPT);
void UpdateExceptionSpec(FunctionDecl *FD,
                         const FunctionProtoType::ExceptionSpecInfo &ESI);
bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
bool CheckDistantExceptionSpec(QualType T);
bool CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New);
bool CheckEquivalentExceptionSpec(
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool CheckEquivalentExceptionSpec(
    const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
    const FunctionProtoType *Old, SourceLocation OldLoc,
    const FunctionProtoType *New, SourceLocation NewLoc);
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
bool CheckExceptionSpecSubset(const PartialDiagnostic &DiagID,
                              const PartialDiagnostic &NestedDiagID,
                              const PartialDiagnostic &NoteID,
                              const PartialDiagnostic &NoThrowDiagID,
                              const FunctionProtoType *Superset,
                              SourceLocation SuperLoc,
                              const FunctionProtoType *Subset,
                              SourceLocation SubLoc);
bool CheckParamExceptionSpec(const PartialDiagnostic &NestedDiagID,
                             const PartialDiagnostic &NoteID,
                             const FunctionProtoType *Target,
                             SourceLocation TargetLoc,
                             const FunctionProtoType *Source,
                             SourceLocation SourceLoc);

TypeResult ActOnTypeName(Scope *S, Declarator &D);

/// The parser has parsed the context-sensitive type 'instancetype'
/// in an Objective-C message declaration. Return the appropriate type.
ParsedType ActOnObjCInstanceType(SourceLocation Loc);

/// Abstract class used to diagnose incomplete types.
struct TypeDiagnoser {
  TypeDiagnoser() {}

  virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = 0;
  virtual ~TypeDiagnoser() {}
};

static int getPrintable(int I) { return I; }
static unsigned getPrintable(unsigned I) { return I; }
static bool getPrintable(bool B) { return B; }
static const char * getPrintable(const char *S) { return S; }
static StringRef getPrintable(StringRef S) { return S; }
static const std::string &getPrintable(const std::string &S) { return S; }
static const IdentifierInfo *getPrintable(const IdentifierInfo *II) {
  return II;
}
static DeclarationName getPrintable(DeclarationName N) { return N; }
static QualType getPrintable(QualType T) { return T; }
static SourceRange getPrintable(SourceRange R) { return R; }
static SourceRange getPrintable(SourceLocation L) { return L; }
static SourceRange getPrintable(const Expr *E) { return E->getSourceRange(); }
static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange();}

template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
protected:
  unsigned DiagID;
  std::tuple<const Ts &...> Args;

  template <std::size_t... Is>
  void emit(const SemaDiagnosticBuilder &DB,
            std::index_sequence<Is...>) const {
    // Apply all tuple elements to the builder in order.
    bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
    (void)Dummy;
  }

public:
  BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
      : TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
    assert(DiagID != 0 && "no diagnostic for type diagnoser")(static_cast <bool> (DiagID != 0 && "no diagnostic for type diagnoser"
) ? void (0) : __assert_fail ("DiagID != 0 && \"no diagnostic for type diagnoser\""
, "clang/include/clang/Sema/Sema.h", 2201, __extension__ __PRETTY_FUNCTION__
));
  }

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
    emit(DB, std::index_sequence_for<Ts...>());
    DB << T;
  }
};

/// Do a check to make sure \p Name looks like a legal argument for the
/// swift_name attribute applied to decl \p D.  Raise a diagnostic if the name
/// is invalid for the given declaration.
///
/// \p AL is used to provide caret diagnostics in case of a malformed name.
///
/// \returns true if the name is a valid swift name for \p D, false otherwise.
bool DiagnoseSwiftName(Decl *D, StringRef Name, SourceLocation Loc,
                       const ParsedAttr &AL, bool IsAsync);

/// A derivative of BoundTypeDiagnoser for which the diagnostic's type
/// parameter is preceded by a 0/1 enum that is 1 if the type is sizeless.
/// For example, a diagnostic with no other parameters would generally have
/// the form "...%select{incomplete|sizeless}0 type %1...".
template <typename... Ts>
class SizelessTypeDiagnoser : public BoundTypeDiagnoser<Ts...> {
public:
  SizelessTypeDiagnoser(unsigned DiagID, const Ts &... Args)
      : BoundTypeDiagnoser<Ts...>(DiagID, Args...) {}

  void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
    const SemaDiagnosticBuilder &DB = S.Diag(Loc, this->DiagID);
    this->emit(DB, std::index_sequence_for<Ts...>());
    DB << T->isSizelessType() << T;
  }
};

enum class CompleteTypeKind {
  /// Apply the normal rules for complete types.  In particular,
  /// treat all sizeless types as incomplete.
  Normal,

  /// Relax the normal rules for complete types so that they include
  /// sizeless built-in types.
  AcceptSizeless,

  // FIXME: Eventually we should flip the default to Normal and opt in
  // to AcceptSizeless rather than opt out of it.
  Default = AcceptSizeless
};

enum class AcceptableKind { Visible, Reachable };

2254private:
/// Methods for marking which expressions involve dereferencing a pointer
/// marked with the 'noderef' attribute. Expressions are checked bottom up as
/// they are parsed, meaning that a noderef pointer may not be accessed. For
/// example, in `&*p` where `p` is a noderef pointer, we will first parse the
/// `*p`, but need to check that `address of` is called on it. This requires
/// keeping a container of all pending expressions and checking if the address
/// of them are eventually taken.
void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
void CheckAddressOfNoDeref(const Expr *E);
void CheckMemberAccessOfNoDeref(const MemberExpr *E);

bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
                             CompleteTypeKind Kind, TypeDiagnoser *Diagnoser);

struct ModuleScope {
  SourceLocation BeginLoc;
  clang::Module *Module = nullptr;
  bool ModuleInterface = false;
  VisibleModuleSet OuterVisibleModules;
};
/// The modules we're currently parsing.
llvm::SmallVector<ModuleScope, 16> ModuleScopes;

/// For an interface unit, this is the implicitly imported interface unit.
clang::Module *ThePrimaryInterface = nullptr;

/// The explicit global module fragment of the current translation unit.
/// The explicit Global Module Fragment, as specified in C++
/// [module.global.frag].
clang::Module *TheGlobalModuleFragment = nullptr;

/// The implicit global module fragments of the current translation unit.
/// We would only create at most two implicit global module fragments to
/// avoid performance penalties when there are many language linkage
/// exports.
///
/// The contents in the implicit global module fragment can't be discarded
/// no matter if it is exported or not.
clang::Module *TheImplicitGlobalModuleFragment = nullptr;
clang::Module *TheExportedImplicitGlobalModuleFragment = nullptr;

/// Namespace definitions that we will export when they finish.
llvm::SmallPtrSet<const NamespaceDecl*, 8> DeferredExportedNamespaces;

/// In a C++ standard module, inline declarations require a definition to be
/// present at the end of a definition domain.  This set holds the decls to
/// be checked at the end of the TU.
llvm::SmallPtrSet<const FunctionDecl *, 8> PendingInlineFuncDecls;

/// Helper function to judge if we are in module purview.
/// Return false if we are not in a module.
bool isCurrentModulePurview() const {
  return getCurrentModule() ? getCurrentModule()->isModulePurview() : false;
}

/// Enter the scope of the explicit global module fragment.
Module *PushGlobalModuleFragment(SourceLocation BeginLoc);
/// Leave the scope of the explicit global module fragment.
void PopGlobalModuleFragment();

/// Enter the scope of an implicit global module fragment.
Module *PushImplicitGlobalModuleFragment(SourceLocation BeginLoc,
                                         bool IsExported);
/// Leave the scope of an implicit global module fragment.
void PopImplicitGlobalModuleFragment();

VisibleModuleSet VisibleModules;

/// Cache for module units which is usable for current module.
llvm::DenseSet<const Module *> UsableModuleUnitsCache;

bool isUsableModule(const Module *M);

bool isAcceptableSlow(const NamedDecl *D, AcceptableKind Kind);

2330public:
/// Get the module unit whose scope we are currently within.
Module *getCurrentModule() const {
  return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
}

/// Is the module scope we are an interface?
bool currentModuleIsInterface() const {
  return ModuleScopes.empty() ? false : ModuleScopes.back().ModuleInterface;
}

/// Is the module scope we are in a C++ Header Unit?
bool currentModuleIsHeaderUnit() const {
  return ModuleScopes.empty() ? false
                              : ModuleScopes.back().Module->isHeaderUnit();
}

/// Get the module owning an entity.
Module *getOwningModule(const Decl *Entity) {
  return Entity->getOwningModule();
}

// Determine whether the module M belongs to the  current TU.
bool isModuleUnitOfCurrentTU(const Module *M) const;

/// Make a merged definition of an existing hidden definition \p ND
/// visible at the specified location.
void makeMergedDefinitionVisible(NamedDecl *ND);

bool isModuleVisible(const Module *M, bool ModulePrivate = false);

// When loading a non-modular PCH files, this is used to restore module
// visibility.
void makeModuleVisible(Module *Mod, SourceLocation ImportLoc) {
  VisibleModules.setVisible(Mod, ImportLoc);
}

/// Determine whether a declaration is visible to name lookup.
bool isVisible(const NamedDecl *D) {
  return D->isUnconditionallyVisible() ||
         isAcceptableSlow(D, AcceptableKind::Visible);
}

/// Determine whether a declaration is reachable.
bool isReachable(const NamedDecl *D) {
  // All visible declarations are reachable.
  return D->isUnconditionallyVisible() ||
         isAcceptableSlow(D, AcceptableKind::Reachable);
}

/// Determine whether a declaration is acceptable (visible/reachable).
bool isAcceptable(const NamedDecl *D, AcceptableKind Kind) {
  return Kind == AcceptableKind::Visible ? isVisible(D) : isReachable(D);
}

/// Determine whether any declaration of an entity is visible.
bool
hasVisibleDeclaration(const NamedDecl *D,
                      llvm::SmallVectorImpl<Module *> *Modules = nullptr) {
  return isVisible(D) || hasVisibleDeclarationSlow(D, Modules);
}

bool hasVisibleDeclarationSlow(const NamedDecl *D,
                               llvm::SmallVectorImpl<Module *> *Modules);
/// Determine whether any declaration of an entity is reachable.
bool
hasReachableDeclaration(const NamedDecl *D,
                        llvm::SmallVectorImpl<Module *> *Modules = nullptr) {
  return isReachable(D) || hasReachableDeclarationSlow(D, Modules);
}
bool hasReachableDeclarationSlow(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

bool hasVisibleMergedDefinition(NamedDecl *Def);
bool hasMergedDefinitionInCurrentModule(NamedDecl *Def);

/// Determine if \p D and \p Suggested have a structurally compatible
/// layout as described in C11 6.2.7/1.
bool hasStructuralCompatLayout(Decl *D, Decl *Suggested);

/// Determine if \p D has a visible definition. If not, suggest a declaration
/// that should be made visible to expose the definition.
bool hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested,
                          bool OnlyNeedComplete = false);
bool hasVisibleDefinition(const NamedDecl *D) {
  NamedDecl *Hidden;
  return hasVisibleDefinition(const_cast<NamedDecl*>(D), &Hidden);
}

/// Determine if \p D has a reachable definition. If not, suggest a
/// declaration that should be made reachable to expose the definition.
bool hasReachableDefinition(NamedDecl *D, NamedDecl **Suggested,
                            bool OnlyNeedComplete = false);
bool hasReachableDefinition(NamedDecl *D) {
  NamedDecl *Hidden;
  return hasReachableDefinition(D, &Hidden);
}

bool hasAcceptableDefinition(NamedDecl *D, NamedDecl **Suggested,
                             AcceptableKind Kind,
                             bool OnlyNeedComplete = false);
bool hasAcceptableDefinition(NamedDecl *D, AcceptableKind Kind) {
  NamedDecl *Hidden;
  return hasAcceptableDefinition(D, &Hidden, Kind);
}

/// Determine if the template parameter \p D has a visible default argument.
bool
hasVisibleDefaultArgument(const NamedDecl *D,
                          llvm::SmallVectorImpl<Module *> *Modules = nullptr);
/// Determine if the template parameter \p D has a reachable default argument.
bool hasReachableDefaultArgument(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);
/// Determine if the template parameter \p D has a reachable default argument.
bool hasAcceptableDefaultArgument(const NamedDecl *D,
                                  llvm::SmallVectorImpl<Module *> *Modules,
                                  Sema::AcceptableKind Kind);

/// Determine if there is a visible declaration of \p D that is an explicit
/// specialization declaration for a specialization of a template. (For a
/// member specialization, use hasVisibleMemberSpecialization.)
bool hasVisibleExplicitSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);
/// Determine if there is a reachable declaration of \p D that is an explicit
/// specialization declaration for a specialization of a template. (For a
/// member specialization, use hasReachableMemberSpecialization.)
bool hasReachableExplicitSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if there is a visible declaration of \p D that is a member
/// specialization declaration (as opposed to an instantiated declaration).
bool hasVisibleMemberSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);
/// Determine if there is a reachable declaration of \p D that is a member
/// specialization declaration (as opposed to an instantiated declaration).
bool hasReachableMemberSpecialization(
    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules = nullptr);

/// Determine if \p A and \p B are equivalent internal linkage declarations
/// from different modules, and thus an ambiguity error can be downgraded to
/// an extension warning.
bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
                                            const NamedDecl *B);
void diagnoseEquivalentInternalLinkageDeclarations(
    SourceLocation Loc, const NamedDecl *D,
    ArrayRef<const NamedDecl *> Equiv);

bool isUsualDeallocationFunction(const CXXMethodDecl *FD);

// Check whether the size of array element of type \p EltTy is a multiple of
// its alignment and return false if it isn't.
bool checkArrayElementAlignment(QualType EltTy, SourceLocation Loc);

bool isCompleteType(SourceLocation Loc, QualType T,
                    CompleteTypeKind Kind = CompleteTypeKind::Default) {
  return !RequireCompleteTypeImpl(Loc, T, Kind, nullptr);
}
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         CompleteTypeKind Kind, TypeDiagnoser &Diagnoser);
bool RequireCompleteType(SourceLocation Loc, QualType T,
                         CompleteTypeKind Kind, unsigned DiagID);

bool RequireCompleteType(SourceLocation Loc, QualType T,
                         TypeDiagnoser &Diagnoser) {
  return RequireCompleteType(Loc, T, CompleteTypeKind::Default, Diagnoser);
}
bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID) {
  return RequireCompleteType(Loc, T, CompleteTypeKind::Default, DiagID);
}

template <typename... Ts>
bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
                         const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteType(Loc, T, Diagnoser);
}

template <typename... Ts>
bool RequireCompleteSizedType(SourceLocation Loc, QualType T, unsigned DiagID,
                              const Ts &... Args) {
  SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteType(Loc, T, CompleteTypeKind::Normal, Diagnoser);
}

/// Get the type of expression E, triggering instantiation to complete the
/// type if necessary -- that is, if the expression refers to a templated
/// static data member of incomplete array type.
///
/// May still return an incomplete type if instantiation was not possible or
/// if the type is incomplete for a different reason. Use
/// RequireCompleteExprType instead if a diagnostic is expected for an
/// incomplete expression type.
QualType getCompletedType(Expr *E);

void completeExprArrayBound(Expr *E);
bool RequireCompleteExprType(Expr *E, CompleteTypeKind Kind,
                             TypeDiagnoser &Diagnoser);
bool RequireCompleteExprType(Expr *E, unsigned DiagID);

template <typename... Ts>
bool RequireCompleteExprType(Expr *E, unsigned DiagID, const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteExprType(E, CompleteTypeKind::Default, Diagnoser);
}

template <typename... Ts>
bool RequireCompleteSizedExprType(Expr *E, unsigned DiagID,
                                  const Ts &... Args) {
  SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireCompleteExprType(E, CompleteTypeKind::Normal, Diagnoser);
}

bool RequireLiteralType(SourceLocation Loc, QualType T,
                        TypeDiagnoser &Diagnoser);
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);

template <typename... Ts>
bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
                        const Ts &...Args) {
  BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
  return RequireLiteralType(Loc, T, Diagnoser);
}

QualType getElaboratedType(ElaboratedTypeKeyword Keyword,
                           const CXXScopeSpec &SS, QualType T,
                           TagDecl *OwnedTagDecl = nullptr);

// Returns the underlying type of a decltype with the given expression.
QualType getDecltypeForExpr(Expr *E);

QualType BuildTypeofExprType(Expr *E, TypeOfKind Kind);
/// If AsUnevaluated is false, E is treated as though it were an evaluated
/// context, such as when building a type for decltype(auto).
QualType BuildDecltypeType(Expr *E, bool AsUnevaluated = true);

using UTTKind = UnaryTransformType::UTTKind;
QualType BuildUnaryTransformType(QualType BaseType, UTTKind UKind,
                                 SourceLocation Loc);
QualType BuiltinEnumUnderlyingType(QualType BaseType, SourceLocation Loc);
QualType BuiltinAddPointer(QualType BaseType, SourceLocation Loc);
QualType BuiltinRemovePointer(QualType BaseType, SourceLocation Loc);
QualType BuiltinDecay(QualType BaseType, SourceLocation Loc);
QualType BuiltinAddReference(QualType BaseType, UTTKind UKind,
                             SourceLocation Loc);
QualType BuiltinRemoveExtent(QualType BaseType, UTTKind UKind,
                             SourceLocation Loc);
QualType BuiltinRemoveReference(QualType BaseType, UTTKind UKind,
                                SourceLocation Loc);
QualType BuiltinChangeCVRQualifiers(QualType BaseType, UTTKind UKind,
                                    SourceLocation Loc);
QualType BuiltinChangeSignedness(QualType BaseType, UTTKind UKind,
                                 SourceLocation Loc);

//===--------------------------------------------------------------------===//
// Symbol table / Decl tracking callbacks: SemaDecl.cpp.
//

struct SkipBodyInfo {
  SkipBodyInfo()
      : ShouldSkip(false), CheckSameAsPrevious(false), Previous(nullptr),
        New(nullptr) {}
  bool ShouldSkip;
  bool CheckSameAsPrevious;
  NamedDecl *Previous;
  NamedDecl *New;
};

DeclGroupPtrTy ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType = nullptr);

void DiagnoseUseOfUnimplementedSelectors();

bool isSimpleTypeSpecifier(tok::TokenKind Kind) const;

ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
                       Scope *S, CXXScopeSpec *SS = nullptr,
                       bool isClassName = false, bool HasTrailingDot = false,
                       ParsedType ObjectType = nullptr,
                       bool IsCtorOrDtorName = false,
                       bool WantNontrivialTypeSourceInfo = false,
                       bool IsClassTemplateDeductionContext = true,
                       ImplicitTypenameContext AllowImplicitTypename =
                           ImplicitTypenameContext::No,
                       IdentifierInfo **CorrectedII = nullptr);
TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
bool isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S);
void DiagnoseUnknownTypeName(IdentifierInfo *&II,
                             SourceLocation IILoc,
                             Scope *S,
                             CXXScopeSpec *SS,
                             ParsedType &SuggestedType,
                             bool IsTemplateName = false);

/// Attempt to behave like MSVC in situations where lookup of an unqualified
/// type name has failed in a dependent context. In these situations, we
/// automatically form a DependentTypeName that will retry lookup in a related
/// scope during instantiation.
ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
                                    SourceLocation NameLoc,
                                    bool IsTemplateTypeArg);

/// Describes the result of the name lookup and resolution performed
/// by \c ClassifyName().
enum NameClassificationKind {
  /// This name is not a type or template in this context, but might be
  /// something else.
  NC_Unknown,
  /// Classification failed; an error has been produced.
  NC_Error,
  /// The name has been typo-corrected to a keyword.
  NC_Keyword,
  /// The name was classified as a type.
  NC_Type,
  /// The name was classified as a specific non-type, non-template
  /// declaration. ActOnNameClassifiedAsNonType should be called to
  /// convert the declaration to an expression.
  NC_NonType,
  /// The name was classified as an ADL-only function name.
  /// ActOnNameClassifiedAsUndeclaredNonType should be called to convert the
  /// result to an expression.
  NC_UndeclaredNonType,
  /// The name denotes a member of a dependent type that could not be
  /// resolved. ActOnNameClassifiedAsDependentNonType should be called to
  /// convert the result to an expression.
  NC_DependentNonType,
  /// The name was classified as an overload set, and an expression
  /// representing that overload set has been formed.
  /// ActOnNameClassifiedAsOverloadSet should be called to form a suitable
  /// expression referencing the overload set.
  NC_OverloadSet,
  /// The name was classified as a template whose specializations are types.
  NC_TypeTemplate,
  /// The name was classified as a variable template name.
  NC_VarTemplate,
  /// The name was classified as a function template name.
  NC_FunctionTemplate,
  /// The name was classified as an ADL-only function template name.
  NC_UndeclaredTemplate,
  /// The name was classified as a concept name.
  NC_Concept,
};

class NameClassification {
  NameClassificationKind Kind;
  union {
    ExprResult Expr;
    NamedDecl *NonTypeDecl;
    TemplateName Template;
    ParsedType Type;
  };

  explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}

public:
  NameClassification(ParsedType Type) : Kind(NC_Type), Type(Type) {}

  NameClassification(const IdentifierInfo *Keyword) : Kind(NC_Keyword) {}

  static NameClassification Error() {
    return NameClassification(NC_Error);
  }

  static NameClassification Unknown() {
    return NameClassification(NC_Unknown);
  }

  static NameClassification OverloadSet(ExprResult E) {
    NameClassification Result(NC_OverloadSet);
    Result.Expr = E;
    return Result;
  }

  static NameClassification NonType(NamedDecl *D) {
    NameClassification Result(NC_NonType);
    Result.NonTypeDecl = D;
    return Result;
  }

  static NameClassification UndeclaredNonType() {
    return NameClassification(NC_UndeclaredNonType);
  }

  static NameClassification DependentNonType() {
    return NameClassification(NC_DependentNonType);
  }

  static NameClassification TypeTemplate(TemplateName Name) {
    NameClassification Result(NC_TypeTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification VarTemplate(TemplateName Name) {
    NameClassification Result(NC_VarTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification FunctionTemplate(TemplateName Name) {
    NameClassification Result(NC_FunctionTemplate);
    Result.Template = Name;
    return Result;
  }

  static NameClassification Concept(TemplateName Name) {
    NameClassification Result(NC_Concept);
    Result.Template = Name;
    return Result;
  }

  static NameClassification UndeclaredTemplate(TemplateName Name) {
    NameClassification Result(NC_UndeclaredTemplate);
    Result.Template = Name;
    return Result;
  }

  NameClassificationKind getKind() const { return Kind; }

  ExprResult getExpression() const {
    assert(Kind == NC_OverloadSet)(static_cast <bool> (Kind == NC_OverloadSet) ? void (0)
 : __assert_fail ("Kind == NC_OverloadSet", "clang/include/clang/Sema/Sema.h"
, 2748, __extension__ __PRETTY_FUNCTION__));
    return Expr;
  }

  ParsedType getType() const {
    assert(Kind == NC_Type)(static_cast <bool> (Kind == NC_Type) ? void (0) : __assert_fail
 ("Kind == NC_Type", "clang/include/clang/Sema/Sema.h", 2753,
 __extension__ __PRETTY_FUNCTION__));
    return Type;
  }

  NamedDecl *getNonTypeDecl() const {
    assert(Kind == NC_NonType)(static_cast <bool> (Kind == NC_NonType) ? void (0) : __assert_fail
 ("Kind == NC_NonType", "clang/include/clang/Sema/Sema.h", 2758
, __extension__ __PRETTY_FUNCTION__));
    return NonTypeDecl;
  }

  TemplateName getTemplateName() const {
    assert(Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate ||(static_cast <bool> (Kind == NC_TypeTemplate || Kind ==
 NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_Concept
 || Kind == NC_UndeclaredTemplate) ? void (0) : __assert_fail
 ("Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_Concept || Kind == NC_UndeclaredTemplate"
, "clang/include/clang/Sema/Sema.h", 2765, __extension__ __PRETTY_FUNCTION__
))
           Kind == NC_VarTemplate || Kind == NC_Concept ||(static_cast <bool> (Kind == NC_TypeTemplate || Kind ==
 NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_Concept
 || Kind == NC_UndeclaredTemplate) ? void (0) : __assert_fail
 ("Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_Concept || Kind == NC_UndeclaredTemplate"
, "clang/include/clang/Sema/Sema.h", 2765, __extension__ __PRETTY_FUNCTION__
))
           Kind == NC_UndeclaredTemplate)(static_cast <bool> (Kind == NC_TypeTemplate || Kind ==
 NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_Concept
 || Kind == NC_UndeclaredTemplate) ? void (0) : __assert_fail
 ("Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate || Kind == NC_VarTemplate || Kind == NC_Concept || Kind == NC_UndeclaredTemplate"
, "clang/include/clang/Sema/Sema.h", 2765, __extension__ __PRETTY_FUNCTION__
));
    return Template;
  }

  TemplateNameKind getTemplateNameKind() const {
    switch (Kind) {
    case NC_TypeTemplate:
      return TNK_Type_template;
    case NC_FunctionTemplate:
      return TNK_Function_template;
    case NC_VarTemplate:
      return TNK_Var_template;
    case NC_Concept:
      return TNK_Concept_template;
    case NC_UndeclaredTemplate:
      return TNK_Undeclared_template;
    default:
      llvm_unreachable("unsupported name classification.")::llvm::llvm_unreachable_internal("unsupported name classification."
, "clang/include/clang/Sema/Sema.h", 2782);
    }
  }
};

/// Perform name lookup on the given name, classifying it based on
/// the results of name lookup and the following token.
///
/// This routine is used by the parser to resolve identifiers and help direct
/// parsing. When the identifier cannot be found, this routine will attempt
/// to correct the typo and classify based on the resulting name.
///
/// \param S The scope in which we're performing name lookup.
///
/// \param SS The nested-name-specifier that precedes the name.
///
/// \param Name The identifier. If typo correction finds an alternative name,
/// this pointer parameter will be updated accordingly.
///
/// \param NameLoc The location of the identifier.
///
/// \param NextToken The token following the identifier. Used to help
/// disambiguate the name.
///
/// \param CCC The correction callback, if typo correction is desired.
NameClassification ClassifyName(Scope *S, CXXScopeSpec &SS,
                                IdentifierInfo *&Name, SourceLocation NameLoc,
                                const Token &NextToken,
                                CorrectionCandidateCallback *CCC = nullptr);

/// Act on the result of classifying a name as an undeclared (ADL-only)
/// non-type declaration.
ExprResult ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
                                                  SourceLocation NameLoc);
/// Act on the result of classifying a name as an undeclared member of a
/// dependent base class.
ExprResult ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
                                                 IdentifierInfo *Name,
                                                 SourceLocation NameLoc,
                                                 bool IsAddressOfOperand);
/// Act on the result of classifying a name as a specific non-type
/// declaration.
ExprResult ActOnNameClassifiedAsNonType(Scope *S, const CXXScopeSpec &SS,
                                        NamedDecl *Found,
                                        SourceLocation NameLoc,
                                        const Token &NextToken);
/// Act on the result of classifying a name as an overload set.
ExprResult ActOnNameClassifiedAsOverloadSet(Scope *S, Expr *OverloadSet);

/// Describes the detailed kind of a template name. Used in diagnostics.
enum class TemplateNameKindForDiagnostics {
  ClassTemplate,
  FunctionTemplate,
  VarTemplate,
  AliasTemplate,
  TemplateTemplateParam,
  Concept,
  DependentTemplate
};
TemplateNameKindForDiagnostics
getTemplateNameKindForDiagnostics(TemplateName Name);

/// Determine whether it's plausible that E was intended to be a
/// template-name.
bool mightBeIntendedToBeTemplateName(ExprResult E, bool &Dependent) {
  if (!getLangOpts().CPlusPlus || E.isInvalid())
    return false;
  Dependent = false;
  if (auto *DRE = dyn_cast<DeclRefExpr>(E.get()))
    return !DRE->hasExplicitTemplateArgs();
  if (auto *ME = dyn_cast<MemberExpr>(E.get()))
    return !ME->hasExplicitTemplateArgs();
  Dependent = true;
  if (auto *DSDRE = dyn_cast<DependentScopeDeclRefExpr>(E.get()))
    return !DSDRE->hasExplicitTemplateArgs();
  if (auto *DSME = dyn_cast<CXXDependentScopeMemberExpr>(E.get()))
    return !DSME->hasExplicitTemplateArgs();
  // Any additional cases recognized here should also be handled by
  // diagnoseExprIntendedAsTemplateName.
  return false;
}
void diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
                                        SourceLocation Less,
                                        SourceLocation Greater);

void warnOnReservedIdentifier(const NamedDecl *D);

Decl *ActOnDeclarator(Scope *S, Declarator &D);

NamedDecl *HandleDeclarator(Scope *S, Declarator &D,
                            MultiTemplateParamsArg TemplateParameterLists);
bool tryToFixVariablyModifiedVarType(TypeSourceInfo *&TInfo,
                                     QualType &T, SourceLocation Loc,
                                     unsigned FailedFoldDiagID);
void RegisterLocallyScopedExternCDecl(NamedDecl *ND, Scope *S);
bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
                                  DeclarationName Name, SourceLocation Loc,
                                  bool IsTemplateId);
void
diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                          SourceLocation FallbackLoc,
                          SourceLocation ConstQualLoc = SourceLocation(),
                          SourceLocation VolatileQualLoc = SourceLocation(),
                          SourceLocation RestrictQualLoc = SourceLocation(),
                          SourceLocation AtomicQualLoc = SourceLocation(),
                          SourceLocation UnalignedQualLoc = SourceLocation());

static bool adjustContextForLocalExternDecl(DeclContext *&DC);
void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
NamedDecl *getShadowedDeclaration(const TypedefNameDecl *D,
                                  const LookupResult &R);
NamedDecl *getShadowedDeclaration(const VarDecl *D, const LookupResult &R);
NamedDecl *getShadowedDeclaration(const BindingDecl *D,
                                  const LookupResult &R);
void CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
                 const LookupResult &R);
void CheckShadow(Scope *S, VarDecl *D);

/// Warn if 'E', which is an expression that is about to be modified, refers
/// to a shadowing declaration.
void CheckShadowingDeclModification(Expr *E, SourceLocation Loc);

void DiagnoseShadowingLambdaDecls(const sema::LambdaScopeInfo *LSI);

2907private:
/// Map of current shadowing declarations to shadowed declarations. Warn if
/// it looks like the user is trying to modify the shadowing declaration.
llvm::DenseMap<const NamedDecl *, const NamedDecl *> ShadowingDecls;

2912public:
void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
void handleTagNumbering(const TagDecl *Tag, Scope *TagScope);
void setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
                                  TypedefNameDecl *NewTD);
void CheckTypedefForVariablyModifiedType(Scope *S, TypedefNameDecl *D);
NamedDecl* ActOnTypedefDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                  TypeSourceInfo *TInfo,
                                  LookupResult &Previous);
NamedDecl* ActOnTypedefNameDecl(Scope* S, DeclContext* DC, TypedefNameDecl *D,
                                LookupResult &Previous, bool &Redeclaration);
NamedDecl *ActOnVariableDeclarator(
    Scope *S, Declarator &D, DeclContext *DC, TypeSourceInfo *TInfo,
    LookupResult &Previous, MultiTemplateParamsArg TemplateParamLists,
    bool &AddToScope, ArrayRef<BindingDecl *> Bindings = std::nullopt);
NamedDecl *
ActOnDecompositionDeclarator(Scope *S, Declarator &D,
                             MultiTemplateParamsArg TemplateParamLists);
// Returns true if the variable declaration is a redeclaration
bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
void CheckVariableDeclarationType(VarDecl *NewVD);
bool DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
                                   Expr *Init);
void CheckCompleteVariableDeclaration(VarDecl *VD);
void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);

NamedDecl* ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                   TypeSourceInfo *TInfo,
                                   LookupResult &Previous,
                                   MultiTemplateParamsArg TemplateParamLists,
                                   bool &AddToScope);
bool AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD);

enum class CheckConstexprKind {
  /// Diagnose issues that are non-constant or that are extensions.
  Diagnose,
  /// Identify whether this function satisfies the formal rules for constexpr
  /// functions in the current lanugage mode (with no extensions).
  CheckValid
};

bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
                                      CheckConstexprKind Kind);

void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
void FindHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
void NoteHiddenVirtualMethods(CXXMethodDecl *MD,
                        SmallVectorImpl<CXXMethodDecl*> &OverloadedMethods);
// Returns true if the function declaration is a redeclaration
bool CheckFunctionDeclaration(Scope *S,
                              FunctionDecl *NewFD, LookupResult &Previous,
                              bool IsMemberSpecialization, bool DeclIsDefn);
bool shouldLinkDependentDeclWithPrevious(Decl *D, Decl *OldDecl);
bool canFullyTypeCheckRedeclaration(ValueDecl *NewD, ValueDecl *OldD,
                                    QualType NewT, QualType OldT);
void CheckMain(FunctionDecl *FD, const DeclSpec &D);
void CheckMSVCRTEntryPoint(FunctionDecl *FD);
void CheckHLSLEntryPoint(FunctionDecl *FD);
Attr *getImplicitCodeSegOrSectionAttrForFunction(const FunctionDecl *FD,
                                                 bool IsDefinition);
void CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D);
Decl *ActOnParamDeclarator(Scope *S, Declarator &D);
ParmVarDecl *BuildParmVarDeclForTypedef(DeclContext *DC,
                                        SourceLocation Loc,
                                        QualType T);
ParmVarDecl *CheckParameter(DeclContext *DC, SourceLocation StartLoc,
                            SourceLocation NameLoc, IdentifierInfo *Name,
                            QualType T, TypeSourceInfo *TSInfo,
                            StorageClass SC);
void ActOnParamDefaultArgument(Decl *param,
                               SourceLocation EqualLoc,
                               Expr *defarg);
void ActOnParamUnparsedDefaultArgument(Decl *param, SourceLocation EqualLoc,
                                       SourceLocation ArgLoc);
void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc);
ExprResult ConvertParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                                       SourceLocation EqualLoc);
void SetParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                             SourceLocation EqualLoc);

// Contexts where using non-trivial C union types can be disallowed. This is
// passed to err_non_trivial_c_union_in_invalid_context.
enum NonTrivialCUnionContext {
  // Function parameter.
  NTCUC_FunctionParam,
  // Function return.
  NTCUC_FunctionReturn,
  // Default-initialized object.
  NTCUC_DefaultInitializedObject,
  // Variable with automatic storage duration.
  NTCUC_AutoVar,
  // Initializer expression that might copy from another object.
  NTCUC_CopyInit,
  // Assignment.
  NTCUC_Assignment,
  // Compound literal.
  NTCUC_CompoundLiteral,
  // Block capture.
  NTCUC_BlockCapture,
  // lvalue-to-rvalue conversion of volatile type.
  NTCUC_LValueToRValueVolatile,
};

/// Emit diagnostics if the initializer or any of its explicit or
/// implicitly-generated subexpressions require copying or
/// default-initializing a type that is or contains a C union type that is
/// non-trivial to copy or default-initialize.
void checkNonTrivialCUnionInInitializer(const Expr *Init, SourceLocation Loc);

// These flags are passed to checkNonTrivialCUnion.
enum NonTrivialCUnionKind {
  NTCUK_Init = 0x1,
  NTCUK_Destruct = 0x2,
  NTCUK_Copy = 0x4,
};

/// Emit diagnostics if a non-trivial C union type or a struct that contains
/// a non-trivial C union is used in an invalid context.
void checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
                           NonTrivialCUnionContext UseContext,
                           unsigned NonTrivialKind);

void AddInitializerToDecl(Decl *dcl, Expr *init, bool DirectInit);
void ActOnUninitializedDecl(Decl *dcl);
void ActOnInitializerError(Decl *Dcl);

void ActOnPureSpecifier(Decl *D, SourceLocation PureSpecLoc);
void ActOnCXXForRangeDecl(Decl *D);
StmtResult ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
                                      IdentifierInfo *Ident,
                                      ParsedAttributes &Attrs);
void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc);
void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
void CheckStaticLocalForDllExport(VarDecl *VD);
void CheckThreadLocalForLargeAlignment(VarDecl *VD);
void FinalizeDeclaration(Decl *D);
DeclGroupPtrTy FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
                                       ArrayRef<Decl *> Group);
DeclGroupPtrTy BuildDeclaratorGroup(MutableArrayRef<Decl *> Group);

/// Should be called on all declarations that might have attached
/// documentation comments.
void ActOnDocumentableDecl(Decl *D);
void ActOnDocumentableDecls(ArrayRef<Decl *> Group);

enum class FnBodyKind {
  /// C++ [dcl.fct.def.general]p1
  /// function-body:
  ///   ctor-initializer[opt] compound-statement
  ///   function-try-block
  Other,
  ///   = default ;
  Default,
  ///   = delete ;
  Delete
};

void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
                                     SourceLocation LocAfterDecls);
void CheckForFunctionRedefinition(
    FunctionDecl *FD, const FunctionDecl *EffectiveDefinition = nullptr,
    SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Declarator &D,
                              MultiTemplateParamsArg TemplateParamLists,
                              SkipBodyInfo *SkipBody = nullptr,
                              FnBodyKind BodyKind = FnBodyKind::Other);
Decl *ActOnStartOfFunctionDef(Scope *S, Decl *D,
                              SkipBodyInfo *SkipBody = nullptr,
                              FnBodyKind BodyKind = FnBodyKind::Other);
void SetFunctionBodyKind(Decl *D, SourceLocation Loc, FnBodyKind BodyKind);
void ActOnStartTrailingRequiresClause(Scope *S, Declarator &D);
ExprResult ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr);
ExprResult ActOnRequiresClause(ExprResult ConstraintExpr);
void ActOnStartOfObjCMethodDef(Scope *S, Decl *D);
bool isObjCMethodDecl(Decl *D) {
  return D && isa<ObjCMethodDecl>(D);
}

/// Determine whether we can delay parsing the body of a function or
/// function template until it is used, assuming we don't care about emitting
/// code for that function.
///
/// This will be \c false if we may need the body of the function in the
/// middle of parsing an expression (where it's impractical to switch to
/// parsing a different function), for instance, if it's constexpr in C++11
/// or has an 'auto' return type in C++14. These cases are essentially bugs.
bool canDelayFunctionBody(const Declarator &D);

/// Determine whether we can skip parsing the body of a function
/// definition, assuming we don't care about analyzing its body or emitting
/// code for that function.
///
/// This will be \c false only if we may need the body of the function in
/// order to parse the rest of the program (for instance, if it is
/// \c constexpr in C++11 or has an 'auto' return type in C++14).
bool canSkipFunctionBody(Decl *D);

/// Determine whether \param D is function like (function or function
/// template) for parsing.
bool isDeclaratorFunctionLike(Declarator &D);

void computeNRVO(Stmt *Body, sema::FunctionScopeInfo *Scope);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body);
Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body, bool IsInstantiation);
Decl *ActOnSkippedFunctionBody(Decl *Decl);
void ActOnFinishInlineFunctionDef(FunctionDecl *D);

/// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
/// attribute for which parsing is delayed.
void ActOnFinishDelayedAttribute(Scope *S, Decl *D, ParsedAttributes &Attrs);

/// Diagnose any unused parameters in the given sequence of
/// ParmVarDecl pointers.
void DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters);

/// Diagnose whether the size of parameters or return value of a
/// function or obj-c method definition is pass-by-value and larger than a
/// specified threshold.
void
DiagnoseSizeOfParametersAndReturnValue(ArrayRef<ParmVarDecl *> Parameters,
                                       QualType ReturnTy, NamedDecl *D);

void DiagnoseInvalidJumps(Stmt *Body);
Decl *ActOnFileScopeAsmDecl(Expr *expr,
                            SourceLocation AsmLoc,
                            SourceLocation RParenLoc);

Decl *ActOnTopLevelStmtDecl(Stmt *Statement);

/// Handle a C++11 empty-declaration and attribute-declaration.
Decl *ActOnEmptyDeclaration(Scope *S, const ParsedAttributesView &AttrList,
                            SourceLocation SemiLoc);

enum class ModuleDeclKind {
  Interface,               ///< 'export module X;'
  Implementation,          ///< 'module X;'
  PartitionInterface,      ///< 'export module X:Y;'
  PartitionImplementation, ///< 'module X:Y;'
};

/// An enumeration to represent the transition of states in parsing module
/// fragments and imports.  If we are not parsing a C++20 TU, or we find
/// an error in state transition, the state is set to NotACXX20Module.
enum class ModuleImportState {
  FirstDecl,      ///< Parsing the first decl in a TU.
  GlobalFragment, ///< after 'module;' but before 'module X;'
  ImportAllowed,  ///< after 'module X;' but before any non-import decl.
  ImportFinished, ///< after any non-import decl.
  PrivateFragmentImportAllowed,  ///< after 'module :private;' but before any
                                 ///< non-import decl.
  PrivateFragmentImportFinished, ///< after 'module :private;' but a
                                 ///< non-import decl has already been seen.
  NotACXX20Module ///< Not a C++20 TU, or an invalid state was found.
};

3169private:
/// The parser has begun a translation unit to be compiled as a C++20
/// Header Unit, helper for ActOnStartOfTranslationUnit() only.
void HandleStartOfHeaderUnit();

3174public:
/// The parser has processed a module-declaration that begins the definition
/// of a module interface or implementation.
DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
                               SourceLocation ModuleLoc, ModuleDeclKind MDK,
                               ModuleIdPath Path, ModuleIdPath Partition,
                               ModuleImportState &ImportState);

/// The parser has processed a global-module-fragment declaration that begins
/// the definition of the global module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc);

/// The parser has processed a private-module-fragment declaration that begins
/// the definition of the private module fragment of the current module unit.
/// \param ModuleLoc The location of the 'module' keyword.
/// \param PrivateLoc The location of the 'private' keyword.
DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
                                              SourceLocation PrivateLoc);

/// The parser has processed a module import declaration.
///
/// \param StartLoc The location of the first token in the declaration. This
///        could be the location of an '@', 'export', or 'import'.
/// \param ExportLoc The location of the 'export' keyword, if any.
/// \param ImportLoc The location of the 'import' keyword.
/// \param Path The module toplevel name as an access path.
/// \param IsPartition If the name is for a partition.
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, ModuleIdPath Path,
                             bool IsPartition = false);
DeclResult ActOnModuleImport(SourceLocation StartLoc,
                             SourceLocation ExportLoc,
                             SourceLocation ImportLoc, Module *M,
                             ModuleIdPath Path = {});

/// The parser has processed a module import translated from a
/// #include or similar preprocessing directive.
void ActOnModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod);

/// The parsed has entered a submodule.
void ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod);
/// The parser has left a submodule.
void ActOnModuleEnd(SourceLocation DirectiveLoc, Module *Mod);

/// Create an implicit import of the given module at the given
/// source location, for error recovery, if possible.
///
/// This routine is typically used when an entity found by name lookup
/// is actually hidden within a module that we know about but the user
/// has forgotten to import.
void createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
                                                Module *Mod);

/// Kinds of missing import. Note, the values of these enumerators correspond
/// to %select values in diagnostics.
enum class MissingImportKind {
  Declaration,
  Definition,
  DefaultArgument,
  ExplicitSpecialization,
  PartialSpecialization
};

/// Diagnose that the specified declaration needs to be visible but
/// isn't, and suggest a module import that would resolve the problem.
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           MissingImportKind MIK, bool Recover = true);
void diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
                           SourceLocation DeclLoc, ArrayRef<Module *> Modules,
                           MissingImportKind MIK, bool Recover);

Decl *ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc,
                           SourceLocation LBraceLoc);
Decl *ActOnFinishExportDecl(Scope *S, Decl *ExportDecl,
                            SourceLocation RBraceLoc);

/// We've found a use of a templated declaration that would trigger an
/// implicit instantiation. Check that any relevant explicit specializations
/// and partial specializations are visible/reachable, and diagnose if not.
void checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec);
void checkSpecializationReachability(SourceLocation Loc, NamedDecl *Spec);

/// Retrieve a suitable printing policy for diagnostics.
PrintingPolicy getPrintingPolicy() const {
  return getPrintingPolicy(Context, PP);
}

/// Retrieve a suitable printing policy for diagnostics.
static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
                                        const Preprocessor &PP);

/// Scope actions.
void ActOnPopScope(SourceLocation Loc, Scope *S);
void ActOnTranslationUnitScope(Scope *S);

Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 const ParsedAttributesView &DeclAttrs,
                                 RecordDecl *&AnonRecord);
Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                                 const ParsedAttributesView &DeclAttrs,
                                 MultiTemplateParamsArg TemplateParams,
                                 bool IsExplicitInstantiation,
                                 RecordDecl *&AnonRecord);

Decl *BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
                                  AccessSpecifier AS,
                                  RecordDecl *Record,
                                  const PrintingPolicy &Policy);

Decl *BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
                                     RecordDecl *Record);

/// Common ways to introduce type names without a tag for use in diagnostics.
/// Keep in sync with err_tag_reference_non_tag.
enum NonTagKind {
  NTK_NonStruct,
  NTK_NonClass,
  NTK_NonUnion,
  NTK_NonEnum,
  NTK_Typedef,
  NTK_TypeAlias,
  NTK_Template,
  NTK_TypeAliasTemplate,
  NTK_TemplateTemplateArgument,
};

/// Given a non-tag type declaration, returns an enum useful for indicating
/// what kind of non-tag type this is.
NonTagKind getNonTagTypeDeclKind(const Decl *D, TagTypeKind TTK);

bool isAcceptableTagRedeclaration(const TagDecl *Previous,
                                  TagTypeKind NewTag, bool isDefinition,
                                  SourceLocation NewTagLoc,
                                  const IdentifierInfo *Name);

enum TagUseKind {
  TUK_Reference,   // Reference to a tag:  'struct foo *X;'
  TUK_Declaration, // Fwd decl of a tag:   'struct foo;'
  TUK_Definition,  // Definition of a tag: 'struct foo { int X; } Y;'
  TUK_Friend       // Friend declaration:  'friend struct foo;'
};

enum OffsetOfKind {
  // Not parsing a type within __builtin_offsetof.
  OOK_Outside,
  // Parsing a type within __builtin_offsetof.
  OOK_Builtin,
  // Parsing a type within macro "offsetof", defined in __buitin_offsetof
  // To improve our diagnostic message.
  OOK_Macro,
};

DeclResult ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                    SourceLocation KWLoc, CXXScopeSpec &SS,
                    IdentifierInfo *Name, SourceLocation NameLoc,
                    const ParsedAttributesView &Attr, AccessSpecifier AS,
                    SourceLocation ModulePrivateLoc,
                    MultiTemplateParamsArg TemplateParameterLists,
                    bool &OwnedDecl, bool &IsDependent,
                    SourceLocation ScopedEnumKWLoc,
                    bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
                    bool IsTypeSpecifier, bool IsTemplateParamOrArg,
                    OffsetOfKind OOK, SkipBodyInfo *SkipBody = nullptr);

DeclResult ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                                   unsigned TagSpec, SourceLocation TagLoc,
                                   CXXScopeSpec &SS, IdentifierInfo *Name,
                                   SourceLocation NameLoc,
                                   const ParsedAttributesView &Attr,
                                   MultiTemplateParamsArg TempParamLists);

TypeResult ActOnDependentTag(Scope *S,
                             unsigned TagSpec,
                             TagUseKind TUK,
                             const CXXScopeSpec &SS,
                             IdentifierInfo *Name,
                             SourceLocation TagLoc,
                             SourceLocation NameLoc);

void ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
               IdentifierInfo *ClassName,
               SmallVectorImpl<Decl *> &Decls);
Decl *ActOnField(Scope *S, Decl *TagD, SourceLocation DeclStart,
                 Declarator &D, Expr *BitfieldWidth);

FieldDecl *HandleField(Scope *S, RecordDecl *TagD, SourceLocation DeclStart,
                       Declarator &D, Expr *BitfieldWidth,
                       InClassInitStyle InitStyle,
                       AccessSpecifier AS);
MSPropertyDecl *HandleMSProperty(Scope *S, RecordDecl *TagD,
                                 SourceLocation DeclStart, Declarator &D,
                                 Expr *BitfieldWidth,
                                 InClassInitStyle InitStyle,
                                 AccessSpecifier AS,
                                 const ParsedAttr &MSPropertyAttr);

FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
                          TypeSourceInfo *TInfo,
                          RecordDecl *Record, SourceLocation Loc,
                          bool Mutable, Expr *BitfieldWidth,
                          InClassInitStyle InitStyle,
                          SourceLocation TSSL,
                          AccessSpecifier AS, NamedDecl *PrevDecl,
                          Declarator *D = nullptr);

bool CheckNontrivialField(FieldDecl *FD);
void DiagnoseNontrivial(const CXXRecordDecl *Record, CXXSpecialMember CSM);

enum TrivialABIHandling {
  /// The triviality of a method unaffected by "trivial_abi".
  TAH_IgnoreTrivialABI,

  /// The triviality of a method affected by "trivial_abi".
  TAH_ConsiderTrivialABI
};

bool SpecialMemberIsTrivial(CXXMethodDecl *MD, CXXSpecialMember CSM,
                            TrivialABIHandling TAH = TAH_IgnoreTrivialABI,
                            bool Diagnose = false);

/// For a defaulted function, the kind of defaulted function that it is.
class DefaultedFunctionKind {
  CXXSpecialMember SpecialMember : 8;
  DefaultedComparisonKind Comparison : 8;

public:
  DefaultedFunctionKind()
      : SpecialMember(CXXInvalid), Comparison(DefaultedComparisonKind::None) {
  }
  DefaultedFunctionKind(CXXSpecialMember CSM)
      : SpecialMember(CSM), Comparison(DefaultedComparisonKind::None) {}
  DefaultedFunctionKind(DefaultedComparisonKind Comp)
      : SpecialMember(CXXInvalid), Comparison(Comp) {}

  bool isSpecialMember() const { return SpecialMember != CXXInvalid; }
  bool isComparison() const {
    return Comparison != DefaultedComparisonKind::None;
  }

  explicit operator bool() const {
    return isSpecialMember() || isComparison();
  }

  CXXSpecialMember asSpecialMember() const { return SpecialMember; }
  DefaultedComparisonKind asComparison() const { return Comparison; }

  /// Get the index of this function kind for use in diagnostics.
  unsigned getDiagnosticIndex() const {
    static_assert(CXXInvalid > CXXDestructor,
                  "invalid should have highest index");
    static_assert((unsigned)DefaultedComparisonKind::None == 0,
                  "none should be equal to zero");
    return SpecialMember + (unsigned)Comparison;
  }
};

DefaultedFunctionKind getDefaultedFunctionKind(const FunctionDecl *FD);

CXXSpecialMember getSpecialMember(const CXXMethodDecl *MD) {
  return getDefaultedFunctionKind(MD).asSpecialMember();
}
DefaultedComparisonKind getDefaultedComparisonKind(const FunctionDecl *FD) {
  return getDefaultedFunctionKind(FD).asComparison();
}

void ActOnLastBitfield(SourceLocation DeclStart,
                       SmallVectorImpl<Decl *> &AllIvarDecls);
Decl *ActOnIvar(Scope *S, SourceLocation DeclStart,
                Declarator &D, Expr *BitfieldWidth,
                tok::ObjCKeywordKind visibility);

// This is used for both record definitions and ObjC interface declarations.
void ActOnFields(Scope *S, SourceLocation RecLoc, Decl *TagDecl,
                 ArrayRef<Decl *> Fields, SourceLocation LBrac,
                 SourceLocation RBrac, const ParsedAttributesView &AttrList);

/// ActOnTagStartDefinition - Invoked when we have entered the
/// scope of a tag's definition (e.g., for an enumeration, class,
/// struct, or union).
void ActOnTagStartDefinition(Scope *S, Decl *TagDecl);

/// Perform ODR-like check for C/ObjC when merging tag types from modules.
/// Differently from C++, actually parse the body and reject / error out
/// in case of a structural mismatch.
bool ActOnDuplicateDefinition(Decl *Prev, SkipBodyInfo &SkipBody);

/// Check ODR hashes for C/ObjC when merging types from modules.
/// Differently from C++, actually parse the body and reject in case
/// of a mismatch.
template <typename T,
          typename = std::enable_if_t<std::is_base_of<NamedDecl, T>::value>>
bool ActOnDuplicateODRHashDefinition(T *Duplicate, T *Previous) {
  if (Duplicate->getODRHash() != Previous->getODRHash())
    return false;

  // Make the previous decl visible.
  makeMergedDefinitionVisible(Previous);
  return true;
}

typedef void *SkippedDefinitionContext;

/// Invoked when we enter a tag definition that we're skipping.
SkippedDefinitionContext ActOnTagStartSkippedDefinition(Scope *S, Decl *TD);

void ActOnObjCContainerStartDefinition(ObjCContainerDecl *IDecl);

/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
/// C++ record definition's base-specifiers clause and are starting its
/// member declarations.
void ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagDecl,
                                     SourceLocation FinalLoc,
                                     bool IsFinalSpelledSealed,
                                     bool IsAbstract,
                                     SourceLocation LBraceLoc);

/// ActOnTagFinishDefinition - Invoked once we have finished parsing
/// the definition of a tag (enumeration, class, struct, or union).
void ActOnTagFinishDefinition(Scope *S, Decl *TagDecl,
                              SourceRange BraceRange);

void ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context);

void ActOnObjCContainerFinishDefinition();

/// Invoked when we must temporarily exit the objective-c container
/// scope for parsing/looking-up C constructs.
///
/// Must be followed by a call to \see ActOnObjCReenterContainerContext
void ActOnObjCTemporaryExitContainerContext(ObjCContainerDecl *ObjCCtx);
void ActOnObjCReenterContainerContext(ObjCContainerDecl *ObjCCtx);

/// ActOnTagDefinitionError - Invoked when there was an unrecoverable
/// error parsing the definition of a tag.
void ActOnTagDefinitionError(Scope *S, Decl *TagDecl);

EnumConstantDecl *CheckEnumConstant(EnumDecl *Enum,
                                    EnumConstantDecl *LastEnumConst,
                                    SourceLocation IdLoc,
                                    IdentifierInfo *Id,
                                    Expr *val);
bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
                            QualType EnumUnderlyingTy, bool IsFixed,
                            const EnumDecl *Prev);

/// Determine whether the body of an anonymous enumeration should be skipped.
/// \param II The name of the first enumerator.
SkipBodyInfo shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
                                    SourceLocation IILoc);

Decl *ActOnEnumConstant(Scope *S, Decl *EnumDecl, Decl *LastEnumConstant,
                        SourceLocation IdLoc, IdentifierInfo *Id,
                        const ParsedAttributesView &Attrs,
                        SourceLocation EqualLoc, Expr *Val);
void ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
                   Decl *EnumDecl, ArrayRef<Decl *> Elements, Scope *S,
                   const ParsedAttributesView &Attr);

/// Set the current declaration context until it gets popped.
void PushDeclContext(Scope *S, DeclContext *DC);
void PopDeclContext();

/// EnterDeclaratorContext - Used when we must lookup names in the context
/// of a declarator's nested name specifier.
void EnterDeclaratorContext(Scope *S, DeclContext *DC);
void ExitDeclaratorContext(Scope *S);

/// Enter a template parameter scope, after it's been associated with a particular
/// DeclContext. Causes lookup within the scope to chain through enclosing contexts
/// in the correct order.
void EnterTemplatedContext(Scope *S, DeclContext *DC);

/// Push the parameters of D, which must be a function, into scope.
void ActOnReenterFunctionContext(Scope* S, Decl* D);
void ActOnExitFunctionContext();

/// If \p AllowLambda is true, treat lambda as function.
DeclContext *getFunctionLevelDeclContext(bool AllowLambda = false) const;

/// Returns a pointer to the innermost enclosing function, or nullptr if the
/// current context is not inside a function. If \p AllowLambda is true,
/// this can return the call operator of an enclosing lambda, otherwise
/// lambdas are skipped when looking for an enclosing function.
FunctionDecl *getCurFunctionDecl(bool AllowLambda = false) const;

/// getCurMethodDecl - If inside of a method body, this returns a pointer to
/// the method decl for the method being parsed.  If we're currently
/// in a 'block', this returns the containing context.
ObjCMethodDecl *getCurMethodDecl();

/// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
/// or C function we're in, otherwise return null.  If we're currently
/// in a 'block', this returns the containing context.
NamedDecl *getCurFunctionOrMethodDecl() const;

/// Add this decl to the scope shadowed decl chains.
void PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext = true);

/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
/// true if 'D' belongs to the given declaration context.
///
/// \param AllowInlineNamespace If \c true, allow the declaration to be in the
///        enclosing namespace set of the context, rather than contained
///        directly within it.
bool isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S = nullptr,
                   bool AllowInlineNamespace = false) const;

/// Finds the scope corresponding to the given decl context, if it
/// happens to be an enclosing scope.  Otherwise return NULL.
static Scope *getScopeForDeclContext(Scope *S, DeclContext *DC);

/// Subroutines of ActOnDeclarator().
TypedefDecl *ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
                              TypeSourceInfo *TInfo);
bool isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New);

/// Describes the kind of merge to perform for availability
/// attributes (including "deprecated", "unavailable", and "availability").
enum AvailabilityMergeKind {
  /// Don't merge availability attributes at all.
  AMK_None,
  /// Merge availability attributes for a redeclaration, which requires
  /// an exact match.
  AMK_Redeclaration,
  /// Merge availability attributes for an override, which requires
  /// an exact match or a weakening of constraints.
  AMK_Override,
  /// Merge availability attributes for an implementation of
  /// a protocol requirement.
  AMK_ProtocolImplementation,
  /// Merge availability attributes for an implementation of
  /// an optional protocol requirement.
  AMK_OptionalProtocolImplementation
};

/// Describes the kind of priority given to an availability attribute.
///
/// The sum of priorities deteremines the final priority of the attribute.
/// The final priority determines how the attribute will be merged.
/// An attribute with a lower priority will always remove higher priority
/// attributes for the specified platform when it is being applied. An
/// attribute with a higher priority will not be applied if the declaration
/// already has an availability attribute with a lower priority for the
/// specified platform. The final prirority values are not expected to match
/// the values in this enumeration, but instead should be treated as a plain
/// integer value. This enumeration just names the priority weights that are
/// used to calculate that final vaue.
enum AvailabilityPriority : int {
  /// The availability attribute was specified explicitly next to the
  /// declaration.
  AP_Explicit = 0,

  /// The availability attribute was applied using '#pragma clang attribute'.
  AP_PragmaClangAttribute = 1,

  /// The availability attribute for a specific platform was inferred from
  /// an availability attribute for another platform.
  AP_InferredFromOtherPlatform = 2
};

/// Attribute merging methods. Return true if a new attribute was added.
AvailabilityAttr *
mergeAvailabilityAttr(NamedDecl *D, const AttributeCommonInfo &CI,
                      IdentifierInfo *Platform, bool Implicit,
                      VersionTuple Introduced, VersionTuple Deprecated,
                      VersionTuple Obsoleted, bool IsUnavailable,
                      StringRef Message, bool IsStrict, StringRef Replacement,
                      AvailabilityMergeKind AMK, int Priority);
TypeVisibilityAttr *
mergeTypeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                        TypeVisibilityAttr::VisibilityType Vis);
VisibilityAttr *mergeVisibilityAttr(Decl *D, const AttributeCommonInfo &CI,
                                    VisibilityAttr::VisibilityType Vis);
UuidAttr *mergeUuidAttr(Decl *D, const AttributeCommonInfo &CI,
                        StringRef UuidAsWritten, MSGuidDecl *GuidDecl);
DLLImportAttr *mergeDLLImportAttr(Decl *D, const AttributeCommonInfo &CI);
DLLExportAttr *mergeDLLExportAttr(Decl *D, const AttributeCommonInfo &CI);
MSInheritanceAttr *mergeMSInheritanceAttr(Decl *D,
                                          const AttributeCommonInfo &CI,
                                          bool BestCase,
                                          MSInheritanceModel Model);
ErrorAttr *mergeErrorAttr(Decl *D, const AttributeCommonInfo &CI,
                          StringRef NewUserDiagnostic);
FormatAttr *mergeFormatAttr(Decl *D, const AttributeCommonInfo &CI,
                            IdentifierInfo *Format, int FormatIdx,
                            int FirstArg);
SectionAttr *mergeSectionAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
CodeSegAttr *mergeCodeSegAttr(Decl *D, const AttributeCommonInfo &CI,
                              StringRef Name);
AlwaysInlineAttr *mergeAlwaysInlineAttr(Decl *D,
                                        const AttributeCommonInfo &CI,
                                        const IdentifierInfo *Ident);
MinSizeAttr *mergeMinSizeAttr(Decl *D, const AttributeCommonInfo &CI);
SwiftNameAttr *mergeSwiftNameAttr(Decl *D, const SwiftNameAttr &SNA,
                                  StringRef Name);
OptimizeNoneAttr *mergeOptimizeNoneAttr(Decl *D,
                                        const AttributeCommonInfo &CI);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D, const ParsedAttr &AL);
InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D,
                                              const InternalLinkageAttr &AL);
WebAssemblyImportNameAttr *mergeImportNameAttr(
    Decl *D, const WebAssemblyImportNameAttr &AL);
WebAssemblyImportModuleAttr *mergeImportModuleAttr(
    Decl *D, const WebAssemblyImportModuleAttr &AL);
EnforceTCBAttr *mergeEnforceTCBAttr(Decl *D, const EnforceTCBAttr &AL);
EnforceTCBLeafAttr *mergeEnforceTCBLeafAttr(Decl *D,
                                            const EnforceTCBLeafAttr &AL);
BTFDeclTagAttr *mergeBTFDeclTagAttr(Decl *D, const BTFDeclTagAttr &AL);
HLSLNumThreadsAttr *mergeHLSLNumThreadsAttr(Decl *D,
                                            const AttributeCommonInfo &AL,
                                            int X, int Y, int Z);
HLSLShaderAttr *mergeHLSLShaderAttr(Decl *D, const AttributeCommonInfo &AL,
                                    HLSLShaderAttr::ShaderType ShaderType);

void mergeDeclAttributes(NamedDecl *New, Decl *Old,
                         AvailabilityMergeKind AMK = AMK_Redeclaration);
void MergeTypedefNameDecl(Scope *S, TypedefNameDecl *New,
                          LookupResult &OldDecls);
bool MergeFunctionDecl(FunctionDecl *New, NamedDecl *&Old, Scope *S,
                       bool MergeTypeWithOld, bool NewDeclIsDefn);
bool MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
                                  Scope *S, bool MergeTypeWithOld);
void mergeObjCMethodDecls(ObjCMethodDecl *New, ObjCMethodDecl *Old);
void MergeVarDecl(VarDecl *New, LookupResult &Previous);
void MergeVarDeclTypes(VarDecl *New, VarDecl *Old, bool MergeTypeWithOld);
void MergeVarDeclExceptionSpecs(VarDecl *New, VarDecl *Old);
bool checkVarDeclRedefinition(VarDecl *OldDefn, VarDecl *NewDefn);
void notePreviousDefinition(const NamedDecl *Old, SourceLocation New);
bool MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old, Scope *S);

// AssignmentAction - This is used by all the assignment diagnostic functions
// to represent what is actually causing the operation
enum AssignmentAction {
  AA_Assigning,
  AA_Passing,
  AA_Returning,
  AA_Converting,
  AA_Initializing,
  AA_Sending,
  AA_Casting,
  AA_Passing_CFAudited
};

/// C++ Overloading.
enum OverloadKind {
  /// This is a legitimate overload: the existing declarations are
  /// functions or function templates with different signatures.
  Ovl_Overload,

  /// This is not an overload because the signature exactly matches
  /// an existing declaration.
  Ovl_Match,

  /// This is not an overload because the lookup results contain a
  /// non-function.
  Ovl_NonFunction
};
OverloadKind CheckOverload(Scope *S,
                           FunctionDecl *New,
                           const LookupResult &OldDecls,
                           NamedDecl *&OldDecl,
                           bool UseMemberUsingDeclRules);
bool IsOverload(FunctionDecl *New, FunctionDecl *Old,
                bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs = true,
                bool ConsiderRequiresClauses = true);

// Calculates whether the expression Constraint depends on an enclosing
// template, for the purposes of [temp.friend] p9.
// TemplateDepth is the 'depth' of the friend function, which is used to
// compare whether a declaration reference is referring to a containing
// template, or just the current friend function. A 'lower' TemplateDepth in
// the AST refers to a 'containing' template. As the constraint is
// uninstantiated, this is relative to the 'top' of the TU.
bool
ConstraintExpressionDependsOnEnclosingTemplate(const FunctionDecl *Friend,
                                               unsigned TemplateDepth,
                                               const Expr *Constraint);

// Calculates whether the friend function depends on an enclosing template for
// the purposes of [temp.friend] p9.
bool FriendConstraintsDependOnEnclosingTemplate(const FunctionDecl *FD);

// Calculates whether two constraint expressions are equal irrespective of a
// difference in 'depth'. This takes a pair of optional 'NamedDecl's 'Old' and
// 'New', which are the "source" of the constraint, since this is necessary
// for figuring out the relative 'depth' of the constraint. The depth of the
// 'primary template' and the 'instantiated from' templates aren't necessarily
// the same, such as a case when one is a 'friend' defined in a class.
bool AreConstraintExpressionsEqual(const NamedDecl *Old,
                                   const Expr *OldConstr,
                                   const NamedDecl *New,
                                   const Expr *NewConstr);

enum class AllowedExplicit {
  /// Allow no explicit functions to be used.
  None,
  /// Allow explicit conversion functions but not explicit constructors.
  Conversions,
  /// Allow both explicit conversion functions and explicit constructors.
  All
};

ImplicitConversionSequence
TryImplicitConversion(Expr *From, QualType ToType,
                      bool SuppressUserConversions,
                      AllowedExplicit AllowExplicit,
                      bool InOverloadResolution,
                      bool CStyle,
                      bool AllowObjCWritebackConversion);

bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
bool IsComplexPromotion(QualType FromType, QualType ToType);
bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
                         bool InOverloadResolution,
                         QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCPointerConversion(QualType FromType, QualType ToType,
                             QualType& ConvertedType, bool &IncompatibleObjC);
bool isObjCWritebackConversion(QualType FromType, QualType ToType,
                               QualType &ConvertedType);
bool IsBlockPointerConversion(QualType FromType, QualType ToType,
                              QualType& ConvertedType);
bool FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
                                const FunctionProtoType *NewType,
                                unsigned *ArgPos = nullptr,
                                bool Reversed = false);
void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
                                QualType FromType, QualType ToType);

void maybeExtendBlockObject(ExprResult &E);
CastKind PrepareCastToObjCObjectPointer(ExprResult &E);
bool CheckPointerConversion(Expr *From, QualType ToType,
                            CastKind &Kind,
                            CXXCastPath& BasePath,
                            bool IgnoreBaseAccess,
                            bool Diagnose = true);
bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
                               bool InOverloadResolution,
                               QualType &ConvertedType);
bool CheckMemberPointerConversion(Expr *From, QualType ToType,
                                  CastKind &Kind,
                                  CXXCastPath &BasePath,
   