SemaType.cpp

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//===--- SemaType.cpp - Semantic Analysis for Types -----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//  This file implements type-related semantic analysis.
//
//===----------------------------------------------------------------------===//
 
#include "TypeLocBuilder.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/ASTStructuralEquivalence.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/TypeLocVisitor.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "clang/Sema/TemplateInstCallback.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/Support/ErrorHandling.h"
#include <bitset>
#include <optional>
 
using namespace clang;
 
enum TypeDiagSelector {
  TDS_Function,
  TDS_Pointer,
  TDS_ObjCObjOrBlock
};
 
/// isOmittedBlockReturnType - Return true if this declarator is missing a
/// return type because this is a omitted return type on a block literal.
static bool isOmittedBlockReturnType(const Declarator &D) {
  if (D.getContext() != DeclaratorContext::BlockLiteral ||
      D.getDeclSpec().hasTypeSpecifier())
    return false;
 
  if (D.getNumTypeObjects() == 0)
    return true;   // ^{ ... }
 
  if (D.getNumTypeObjects() == 1 &&
      D.getTypeObject(0).Kind == DeclaratorChunk::Function)
    return true;   // ^(int X, float Y) { ... }
 
  return false;
}
 
/// diagnoseBadTypeAttribute - Diagnoses a type attribute which
/// doesn't apply to the given type.
static void diagnoseBadTypeAttribute(Sema &S, const ParsedAttr &attr,
                                     QualType type) {
  TypeDiagSelector WhichType;
  bool useExpansionLoc = true;
  switch (attr.getKind()) {
  case ParsedAttr::AT_ObjCGC:
    WhichType = TDS_Pointer;
    break;
  case ParsedAttr::AT_ObjCOwnership:
    WhichType = TDS_ObjCObjOrBlock;
    break;
  default:
    // Assume everything else was a function attribute.
    WhichType = TDS_Function;
    useExpansionLoc = false;
    break;
  }
 
  SourceLocation loc = attr.getLoc();
  StringRef name = attr.getAttrName()->getName();
 
  // The GC attributes are usually written with macros;  special-case them.
  IdentifierInfo *II = attr.isArgIdent(0) ? attr.getArgAsIdent(0)->Ident
                                          : nullptr;
  if (useExpansionLoc && loc.isMacroID() && II) {
    if (II->isStr("strong")) {
      if (S.findMacroSpelling(loc, "__strong")) name = "__strong";
    } else if (II->isStr("weak")) {
      if (S.findMacroSpelling(loc, "__weak")) name = "__weak";
    }
  }
 
  S.Diag(loc, diag::warn_type_attribute_wrong_type) << name << WhichType
    << type;
}
 
// objc_gc applies to Objective-C pointers or, otherwise, to the
// smallest available pointer type (i.e. 'void*' in 'void**').
#define OBJC_POINTER_TYPE_ATTRS_CASELIST                                       \
  case ParsedAttr::AT_ObjCGC:                                                  \
  case ParsedAttr::AT_ObjCOwnership
 
// Calling convention attributes.
#define CALLING_CONV_ATTRS_CASELIST                                            \
  case ParsedAttr::AT_CDecl:                                                   \
  case ParsedAttr::AT_FastCall:                                                \
  case ParsedAttr::AT_StdCall:                                                 \
  case ParsedAttr::AT_ThisCall:                                                \
  case ParsedAttr::AT_RegCall:                                                 \
  case ParsedAttr::AT_Pascal:                                                  \
  case ParsedAttr::AT_SwiftCall:                                               \
  case ParsedAttr::AT_SwiftAsyncCall:                                          \
  case ParsedAttr::AT_VectorCall:                                              \
  case ParsedAttr::AT_AArch64VectorPcs:                                        \
  case ParsedAttr::AT_AArch64SVEPcs:                                           \
  case ParsedAttr::AT_AMDGPUKernelCall:                                        \
  case ParsedAttr::AT_MSABI:                                                   \
  case ParsedAttr::AT_SysVABI:                                                 \
  case ParsedAttr::AT_Pcs:                                                     \
  case ParsedAttr::AT_IntelOclBicc:                                            \
  case ParsedAttr::AT_PreserveMost:                                            \
  case ParsedAttr::AT_PreserveAll
 
// Function type attributes.
#define FUNCTION_TYPE_ATTRS_CASELIST                                           \
  case ParsedAttr::AT_NSReturnsRetained:                                       \
  case ParsedAttr::AT_NoReturn:                                                \
  case ParsedAttr::AT_Regparm:                                                 \
  case ParsedAttr::AT_CmseNSCall:                                              \
  case ParsedAttr::AT_AnyX86NoCallerSavedRegisters:                            \
  case ParsedAttr::AT_AnyX86NoCfCheck:                                         \
    CALLING_CONV_ATTRS_CASELIST
 
// Microsoft-specific type qualifiers.
#define MS_TYPE_ATTRS_CASELIST                                                 \
  case ParsedAttr::AT_Ptr32:                                                   \
  case ParsedAttr::AT_Ptr64:                                                   \
  case ParsedAttr::AT_SPtr:                                                    \
  case ParsedAttr::AT_UPtr
 
// Nullability qualifiers.
#define NULLABILITY_TYPE_ATTRS_CASELIST                                        \
  case ParsedAttr::AT_TypeNonNull:                                             \
  case ParsedAttr::AT_TypeNullable:                                            \
  case ParsedAttr::AT_TypeNullableResult:                                      \
  case ParsedAttr::AT_TypeNullUnspecified
 
namespace {
  /// An object which stores processing state for the entire
  /// GetTypeForDeclarator process.
  class TypeProcessingState {
    Sema &sema;
 
    /// The declarator being processed.
    Declarator &declarator;
 
    /// The index of the declarator chunk we're currently processing.
    /// May be the total number of valid chunks, indicating the
    /// DeclSpec.
    unsigned chunkIndex;
 
    /// The original set of attributes on the DeclSpec.
    SmallVector<ParsedAttr *, 2> savedAttrs;
 
    /// A list of attributes to diagnose the uselessness of when the
    /// processing is complete.
    SmallVector<ParsedAttr *, 2> ignoredTypeAttrs;
 
    /// Attributes corresponding to AttributedTypeLocs that we have not yet
    /// populated.
    // FIXME: The two-phase mechanism by which we construct Types and fill
    // their TypeLocs makes it hard to correctly assign these. We keep the
    // attributes in creation order as an attempt to make them line up
    // properly.
    using TypeAttrPair = std::pair<const AttributedType*, const Attr*>;
    SmallVector<TypeAttrPair, 8> AttrsForTypes;
    bool AttrsForTypesSorted = true;
 
    /// MacroQualifiedTypes mapping to macro expansion locations that will be
    /// stored in a MacroQualifiedTypeLoc.
    llvm::DenseMap<const MacroQualifiedType *, SourceLocation> LocsForMacros;
 
    /// Flag to indicate we parsed a noderef attribute. This is used for
    /// validating that noderef was used on a pointer or array.
    bool parsedNoDeref;
 
  public:
    TypeProcessingState(Sema &sema, Declarator &declarator)
        : sema(sema), declarator(declarator),
          chunkIndex(declarator.getNumTypeObjects()), parsedNoDeref(false) {}
 
    Sema &getSema() const {
      return sema;
    }
 
    Declarator &getDeclarator() const {
      return declarator;
    }
 
    bool isProcessingDeclSpec() const {
      return chunkIndex == declarator.getNumTypeObjects();
    }
 
    unsigned getCurrentChunkIndex() const {
      return chunkIndex;
    }
 
    void setCurrentChunkIndex(unsigned idx) {
      assert(idx <= declarator.getNumTypeObjects());
      chunkIndex = idx;
    }
 
    ParsedAttributesView &getCurrentAttributes() const {
      if (isProcessingDeclSpec())
        return getMutableDeclSpec().getAttributes();
      return declarator.getTypeObject(chunkIndex).getAttrs();
    }
 
    /// Save the current set of attributes on the DeclSpec.
    void saveDeclSpecAttrs() {
      // Don't try to save them multiple times.
      if (!savedAttrs.empty())
        return;
 
      DeclSpec &spec = getMutableDeclSpec();
      llvm::append_range(savedAttrs,
                         llvm::make_pointer_range(spec.getAttributes()));
    }
 
    /// Record that we had nowhere to put the given type attribute.
    /// We will diagnose such attributes later.
    void addIgnoredTypeAttr(ParsedAttr &attr) {
      ignoredTypeAttrs.push_back(&attr);
    }
 
    /// Diagnose all the ignored type attributes, given that the
    /// declarator worked out to the given type.
    void diagnoseIgnoredTypeAttrs(QualType type) const {
      for (auto *Attr : ignoredTypeAttrs)
        diagnoseBadTypeAttribute(getSema(), *Attr, type);
    }
 
    /// Get an attributed type for the given attribute, and remember the Attr
    /// object so that we can attach it to the AttributedTypeLoc.
    QualType getAttributedType(Attr *A, QualType ModifiedType,
                               QualType EquivType) {
      QualType T =
          sema.Context.getAttributedType(A->getKind(), ModifiedType, EquivType);
      AttrsForTypes.push_back({cast<AttributedType>(T.getTypePtr()), A});
      AttrsForTypesSorted = false;
      return T;
    }
 
    /// Get a BTFTagAttributed type for the btf_type_tag attribute.
    QualType getBTFTagAttributedType(const BTFTypeTagAttr *BTFAttr,
                                     QualType WrappedType) {
      return sema.Context.getBTFTagAttributedType(BTFAttr, WrappedType);
    }
 
    /// Completely replace the \c auto in \p TypeWithAuto by
    /// \p Replacement. Also replace \p TypeWithAuto in \c TypeAttrPair if
    /// necessary.
    QualType ReplaceAutoType(QualType TypeWithAuto, QualType Replacement) {
      QualType T = sema.ReplaceAutoType(TypeWithAuto, Replacement);
      if (auto *AttrTy = TypeWithAuto->getAs<AttributedType>()) {
        // Attributed type still should be an attributed type after replacement.
        auto *NewAttrTy = cast<AttributedType>(T.getTypePtr());
        for (TypeAttrPair &A : AttrsForTypes) {
          if (A.first == AttrTy)
            A.first = NewAttrTy;
        }
        AttrsForTypesSorted = false;
      }
      return T;
    }
 
    /// Extract and remove the Attr* for a given attributed type.
    const Attr *takeAttrForAttributedType(const AttributedType *AT) {
      if (!AttrsForTypesSorted) {
        llvm::stable_sort(AttrsForTypes, llvm::less_first());
        AttrsForTypesSorted = true;
      }
 
      // FIXME: This is quadratic if we have lots of reuses of the same
      // attributed type.
      for (auto It = std::partition_point(
               AttrsForTypes.begin(), AttrsForTypes.end(),
               [=](const TypeAttrPair &A) { return A.first < AT; });
           It != AttrsForTypes.end() && It->first == AT; ++It) {
        if (It->second) {
          const Attr *Result = It->second;
          It->second = nullptr;
          return Result;
        }
      }
 
      llvm_unreachable("no Attr* for AttributedType*");
    }
 
    SourceLocation
    getExpansionLocForMacroQualifiedType(const MacroQualifiedType *MQT) const {
      auto FoundLoc = LocsForMacros.find(MQT);
      assert(FoundLoc != LocsForMacros.end() &&
             "Unable to find macro expansion location for MacroQualifedType");
      return FoundLoc->second;
    }
 
    void setExpansionLocForMacroQualifiedType(const MacroQualifiedType *MQT,
                                              SourceLocation Loc) {
      LocsForMacros[MQT] = Loc;
    }
 
    void setParsedNoDeref(bool parsed) { parsedNoDeref = parsed; }
 
    bool didParseNoDeref() const { return parsedNoDeref; }
 
    ~TypeProcessingState() {
      if (savedAttrs.empty())
        return;
 
      getMutableDeclSpec().getAttributes().clearListOnly();
      for (ParsedAttr *AL : savedAttrs)
        getMutableDeclSpec().getAttributes().addAtEnd(AL);
    }
 
  private:
    DeclSpec &getMutableDeclSpec() const {
      return const_cast<DeclSpec&>(declarator.getDeclSpec());
    }
  };
} // end anonymous namespace
 
static void moveAttrFromListToList(ParsedAttr &attr,
                                   ParsedAttributesView &fromList,
                                   ParsedAttributesView &toList) {
  fromList.remove(&attr);
  toList.addAtEnd(&attr);
}
 
/// The location of a type attribute.
enum TypeAttrLocation {
  /// The attribute is in the decl-specifier-seq.
  TAL_DeclSpec,
  /// The attribute is part of a DeclaratorChunk.
  TAL_DeclChunk,
  /// The attribute is immediately after the declaration's name.
  TAL_DeclName
};
 
static void processTypeAttrs(TypeProcessingState &state, QualType &type,
                             TypeAttrLocation TAL,
                             const ParsedAttributesView &attrs);
 
static bool handleFunctionTypeAttr(TypeProcessingState &state, ParsedAttr &attr,
                                   QualType &type);
 
static bool handleMSPointerTypeQualifierAttr(TypeProcessingState &state,
                                             ParsedAttr &attr, QualType &type);
 
static bool handleObjCGCTypeAttr(TypeProcessingState &state, ParsedAttr &attr,
                                 QualType &type);
 
static bool handleObjCOwnershipTypeAttr(TypeProcessingState &state,
                                        ParsedAttr &attr, QualType &type);
 
static bool handleObjCPointerTypeAttr(TypeProcessingState &state,
                                      ParsedAttr &attr, QualType &type) {
  if (attr.getKind() == ParsedAttr::AT_ObjCGC)
    return handleObjCGCTypeAttr(state, attr, type);
  assert(attr.getKind() == ParsedAttr::AT_ObjCOwnership);
  return handleObjCOwnershipTypeAttr(state, attr, type);
}
 
/// Given the index of a declarator chunk, check whether that chunk
/// directly specifies the return type of a function and, if so, find
/// an appropriate place for it.
///
/// \param i - a notional index which the search will start
///   immediately inside
///
/// \param onlyBlockPointers Whether we should only look into block
/// pointer types (vs. all pointer types).
static DeclaratorChunk *maybeMovePastReturnType(Declarator &declarator,
                                                unsigned i,
                                                bool onlyBlockPointers) {
  assert(i <= declarator.getNumTypeObjects());
 
  DeclaratorChunk *result = nullptr;
 
  // First, look inwards past parens for a function declarator.
  for (; i != 0; --i) {
    DeclaratorChunk &fnChunk = declarator.getTypeObject(i-1);
    switch (fnChunk.Kind) {
    case DeclaratorChunk::Paren:
      continue;
 
    // If we find anything except a function, bail out.
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Array:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Pipe:
      return result;
 
    // If we do find a function declarator, scan inwards from that,
    // looking for a (block-)pointer declarator.
    case DeclaratorChunk::Function:
      for (--i; i != 0; --i) {
        DeclaratorChunk &ptrChunk = declarator.getTypeObject(i-1);
        switch (ptrChunk.Kind) {
        case DeclaratorChunk::Paren:
        case DeclaratorChunk::Array:
        case DeclaratorChunk::Function:
        case DeclaratorChunk::Reference:
        case DeclaratorChunk::Pipe:
          continue;
 
        case DeclaratorChunk::MemberPointer:
        case DeclaratorChunk::Pointer:
          if (onlyBlockPointers)
            continue;
 
          [[fallthrough]];
 
        case DeclaratorChunk::BlockPointer:
          result = &ptrChunk;
          goto continue_outer;
        }
        llvm_unreachable("bad declarator chunk kind");
      }
 
      // If we run out of declarators doing that, we're done.
      return result;
    }
    llvm_unreachable("bad declarator chunk kind");
 
    // Okay, reconsider from our new point.
  continue_outer: ;
  }
 
  // Ran out of chunks, bail out.
  return result;
}
 
/// Given that an objc_gc attribute was written somewhere on a
/// declaration *other* than on the declarator itself (for which, use
/// distributeObjCPointerTypeAttrFromDeclarator), and given that it
/// didn't apply in whatever position it was written in, try to move
/// it to a more appropriate position.
static void distributeObjCPointerTypeAttr(TypeProcessingState &state,
                                          ParsedAttr &attr, QualType type) {
  Declarator &declarator = state.getDeclarator();
 
  // Move it to the outermost normal or block pointer declarator.
  for (unsigned i = state.getCurrentChunkIndex(); i != 0; --i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i-1);
    switch (chunk.Kind) {
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer: {
      // But don't move an ARC ownership attribute to the return type
      // of a block.
      DeclaratorChunk *destChunk = nullptr;
      if (state.isProcessingDeclSpec() &&
          attr.getKind() == ParsedAttr::AT_ObjCOwnership)
        destChunk = maybeMovePastReturnType(declarator, i - 1,
                                            /*onlyBlockPointers=*/true);
      if (!destChunk) destChunk = &chunk;
 
      moveAttrFromListToList(attr, state.getCurrentAttributes(),
                             destChunk->getAttrs());
      return;
    }
 
    case DeclaratorChunk::Paren:
    case DeclaratorChunk::Array:
      continue;
 
    // We may be starting at the return type of a block.
    case DeclaratorChunk::Function:
      if (state.isProcessingDeclSpec() &&
          attr.getKind() == ParsedAttr::AT_ObjCOwnership) {
        if (DeclaratorChunk *dest = maybeMovePastReturnType(
                                      declarator, i,
                                      /*onlyBlockPointers=*/true)) {
          moveAttrFromListToList(attr, state.getCurrentAttributes(),
                                 dest->getAttrs());
          return;
        }
      }
      goto error;
 
    // Don't walk through these.
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Pipe:
      goto error;
    }
  }
 error:
 
  diagnoseBadTypeAttribute(state.getSema(), attr, type);
}
 
/// Distribute an objc_gc type attribute that was written on the
/// declarator.
static void distributeObjCPointerTypeAttrFromDeclarator(
    TypeProcessingState &state, ParsedAttr &attr, QualType &declSpecType) {
  Declarator &declarator = state.getDeclarator();
 
  // objc_gc goes on the innermost pointer to something that's not a
  // pointer.
  unsigned innermost = -1U;
  bool considerDeclSpec = true;
  for (unsigned i = 0, e = declarator.getNumTypeObjects(); i != e; ++i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i);
    switch (chunk.Kind) {
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
      innermost = i;
      continue;
 
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Paren:
    case DeclaratorChunk::Array:
    case DeclaratorChunk::Pipe:
      continue;
 
    case DeclaratorChunk::Function:
      considerDeclSpec = false;
      goto done;
    }
  }
 done:
 
  // That might actually be the decl spec if we weren't blocked by
  // anything in the declarator.
  if (considerDeclSpec) {
    if (handleObjCPointerTypeAttr(state, attr, declSpecType)) {
      // Splice the attribute into the decl spec.  Prevents the
      // attribute from being applied multiple times and gives
      // the source-location-filler something to work with.
      state.saveDeclSpecAttrs();
      declarator.getMutableDeclSpec().getAttributes().takeOneFrom(
          declarator.getAttributes(), &attr);
      return;
    }
  }
 
  // Otherwise, if we found an appropriate chunk, splice the attribute
  // into it.
  if (innermost != -1U) {
    moveAttrFromListToList(attr, declarator.getAttributes(),
                           declarator.getTypeObject(innermost).getAttrs());
    return;
  }
 
  // Otherwise, diagnose when we're done building the type.
  declarator.getAttributes().remove(&attr);
  state.addIgnoredTypeAttr(attr);
}
 
/// A function type attribute was written somewhere in a declaration
/// *other* than on the declarator itself or in the decl spec.  Given
/// that it didn't apply in whatever position it was written in, try
/// to move it to a more appropriate position.
static void distributeFunctionTypeAttr(TypeProcessingState &state,
                                       ParsedAttr &attr, QualType type) {
  Declarator &declarator = state.getDeclarator();
 
  // Try to push the attribute from the return type of a function to
  // the function itself.
  for (unsigned i = state.getCurrentChunkIndex(); i != 0; --i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i-1);
    switch (chunk.Kind) {
    case DeclaratorChunk::Function:
      moveAttrFromListToList(attr, state.getCurrentAttributes(),
                             chunk.getAttrs());
      return;
 
    case DeclaratorChunk::Paren:
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Array:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Pipe:
      continue;
    }
  }
 
  diagnoseBadTypeAttribute(state.getSema(), attr, type);
}
 
/// Try to distribute a function type attribute to the innermost
/// function chunk or type.  Returns true if the attribute was
/// distributed, false if no location was found.
static bool distributeFunctionTypeAttrToInnermost(
    TypeProcessingState &state, ParsedAttr &attr,
    ParsedAttributesView &attrList, QualType &declSpecType) {
  Declarator &declarator = state.getDeclarator();
 
  // Put it on the innermost function chunk, if there is one.
  for (unsigned i = 0, e = declarator.getNumTypeObjects(); i != e; ++i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i);
    if (chunk.Kind != DeclaratorChunk::Function) continue;
 
    moveAttrFromListToList(attr, attrList, chunk.getAttrs());
    return true;
  }
 
  return handleFunctionTypeAttr(state, attr, declSpecType);
}
 
/// A function type attribute was written in the decl spec.  Try to
/// apply it somewhere.
static void distributeFunctionTypeAttrFromDeclSpec(TypeProcessingState &state,
                                                   ParsedAttr &attr,
                                                   QualType &declSpecType) {
  state.saveDeclSpecAttrs();
 
  // Try to distribute to the innermost.
  if (distributeFunctionTypeAttrToInnermost(
          state, attr, state.getCurrentAttributes(), declSpecType))
    return;
 
  // If that failed, diagnose the bad attribute when the declarator is
  // fully built.
  state.addIgnoredTypeAttr(attr);
}
 
/// A function type attribute was written on the declarator or declaration.
/// Try to apply it somewhere.
/// `Attrs` is the attribute list containing the declaration (either of the
/// declarator or the declaration).
static void distributeFunctionTypeAttrFromDeclarator(TypeProcessingState &state,
                                                     ParsedAttr &attr,
                                                     QualType &declSpecType) {
  Declarator &declarator = state.getDeclarator();
 
  // Try to distribute to the innermost.
  if (distributeFunctionTypeAttrToInnermost(
          state, attr, declarator.getAttributes(), declSpecType))
    return;
 
  // If that failed, diagnose the bad attribute when the declarator is
  // fully built.
  declarator.getAttributes().remove(&attr);
  state.addIgnoredTypeAttr(attr);
}
 
/// Given that there are attributes written on the declarator or declaration
/// itself, try to distribute any type attributes to the appropriate
/// declarator chunk.
///
/// These are attributes like the following:
///   int f ATTR;
///   int (f ATTR)();
/// but not necessarily this:
///   int f() ATTR;
///
/// `Attrs` is the attribute list containing the declaration (either of the
/// declarator or the declaration).
static void distributeTypeAttrsFromDeclarator(TypeProcessingState &state,
                                              QualType &declSpecType) {
  // The called functions in this loop actually remove things from the current
  // list, so iterating over the existing list isn't possible.  Instead, make a
  // non-owning copy and iterate over that.
  ParsedAttributesView AttrsCopy{state.getDeclarator().getAttributes()};
  for (ParsedAttr &attr : AttrsCopy) {
    // Do not distribute [[]] attributes. They have strict rules for what
    // they appertain to.
    if (attr.isStandardAttributeSyntax())
      continue;
 
    switch (attr.getKind()) {
    OBJC_POINTER_TYPE_ATTRS_CASELIST:
      distributeObjCPointerTypeAttrFromDeclarator(state, attr, declSpecType);
      break;
 
    FUNCTION_TYPE_ATTRS_CASELIST:
      distributeFunctionTypeAttrFromDeclarator(state, attr, declSpecType);
      break;
 
    MS_TYPE_ATTRS_CASELIST:
      // Microsoft type attributes cannot go after the declarator-id.
      continue;
 
    NULLABILITY_TYPE_ATTRS_CASELIST:
      // Nullability specifiers cannot go after the declarator-id.
 
    // Objective-C __kindof does not get distributed.
    case ParsedAttr::AT_ObjCKindOf:
      continue;
 
    default:
      break;
    }
  }
}
 
/// Add a synthetic '()' to a block-literal declarator if it is
/// required, given the return type.
static void maybeSynthesizeBlockSignature(TypeProcessingState &state,
                                          QualType declSpecType) {
  Declarator &declarator = state.getDeclarator();
 
  // First, check whether the declarator would produce a function,
  // i.e. whether the innermost semantic chunk is a function.
  if (declarator.isFunctionDeclarator()) {
    // If so, make that declarator a prototyped declarator.
    declarator.getFunctionTypeInfo().hasPrototype = true;
    return;
  }
 
  // If there are any type objects, the type as written won't name a
  // function, regardless of the decl spec type.  This is because a
  // block signature declarator is always an abstract-declarator, and
  // abstract-declarators can't just be parentheses chunks.  Therefore
  // we need to build a function chunk unless there are no type
  // objects and the decl spec type is a function.
  if (!declarator.getNumTypeObjects() && declSpecType->isFunctionType())
    return;
 
  // Note that there *are* cases with invalid declarators where
  // declarators consist solely of parentheses.  In general, these
  // occur only in failed efforts to make function declarators, so
  // faking up the function chunk is still the right thing to do.
 
  // Otherwise, we need to fake up a function declarator.
  SourceLocation loc = declarator.getBeginLoc();
 
  // ...and *prepend* it to the declarator.
  SourceLocation NoLoc;
  declarator.AddInnermostTypeInfo(DeclaratorChunk::getFunction(
      /*HasProto=*/true,
      /*IsAmbiguous=*/false,
      /*LParenLoc=*/NoLoc,
      /*ArgInfo=*/nullptr,
      /*NumParams=*/0,
      /*EllipsisLoc=*/NoLoc,
      /*RParenLoc=*/NoLoc,
      /*RefQualifierIsLvalueRef=*/true,
      /*RefQualifierLoc=*/NoLoc,
      /*MutableLoc=*/NoLoc, EST_None,
      /*ESpecRange=*/SourceRange(),
      /*Exceptions=*/nullptr,
      /*ExceptionRanges=*/nullptr,
      /*NumExceptions=*/0,
      /*NoexceptExpr=*/nullptr,
      /*ExceptionSpecTokens=*/nullptr,
      /*DeclsInPrototype=*/std::nullopt, loc, loc, declarator));
 
  // For consistency, make sure the state still has us as processing
  // the decl spec.
  assert(state.getCurrentChunkIndex() == declarator.getNumTypeObjects() - 1);
  state.setCurrentChunkIndex(declarator.getNumTypeObjects());
}
 
static void diagnoseAndRemoveTypeQualifiers(Sema &S, const DeclSpec &DS,
                                            unsigned &TypeQuals,
                                            QualType TypeSoFar,
                                            unsigned RemoveTQs,
                                            unsigned DiagID) {
  // If this occurs outside a template instantiation, warn the user about
  // it; they probably didn't mean to specify a redundant qualifier.
  typedef std::pair<DeclSpec::TQ, SourceLocation> QualLoc;
  for (QualLoc Qual : {QualLoc(DeclSpec::TQ_const, DS.getConstSpecLoc()),
                       QualLoc(DeclSpec::TQ_restrict, DS.getRestrictSpecLoc()),
                       QualLoc(DeclSpec::TQ_volatile, DS.getVolatileSpecLoc()),
                       QualLoc(DeclSpec::TQ_atomic, DS.getAtomicSpecLoc())}) {
    if (!(RemoveTQs & Qual.first))
      continue;
 
    if (!S.inTemplateInstantiation()) {
      if (TypeQuals & Qual.first)
        S.Diag(Qual.second, DiagID)
          << DeclSpec::getSpecifierName(Qual.first) << TypeSoFar
          << FixItHint::CreateRemoval(Qual.second);
    }
 
    TypeQuals &= ~Qual.first;
  }
}
 
/// Return true if this is omitted block return type. Also check type
/// attributes and type qualifiers when returning true.
static bool checkOmittedBlockReturnType(Sema &S, Declarator &declarator,
                                        QualType Result) {
  if (!isOmittedBlockReturnType(declarator))
    return false;
 
  // Warn if we see type attributes for omitted return type on a block literal.
  SmallVector<ParsedAttr *, 2> ToBeRemoved;
  for (ParsedAttr &AL : declarator.getMutableDeclSpec().getAttributes()) {
    if (AL.isInvalid() || !AL.isTypeAttr())
      continue;
    S.Diag(AL.getLoc(),
           diag::warn_block_literal_attributes_on_omitted_return_type)
        << AL;
    ToBeRemoved.push_back(&AL);
  }
  // Remove bad attributes from the list.
  for (ParsedAttr *AL : ToBeRemoved)
    declarator.getMutableDeclSpec().getAttributes().remove(AL);
 
  // Warn if we see type qualifiers for omitted return type on a block literal.
  const DeclSpec &DS = declarator.getDeclSpec();
  unsigned TypeQuals = DS.getTypeQualifiers();
  diagnoseAndRemoveTypeQualifiers(S, DS, TypeQuals, Result, (unsigned)-1,
      diag::warn_block_literal_qualifiers_on_omitted_return_type);
  declarator.getMutableDeclSpec().ClearTypeQualifiers();
 
  return true;
}
 
/// Apply Objective-C type arguments to the given type.
static QualType applyObjCTypeArgs(Sema &S, SourceLocation loc, QualType type,
                                  ArrayRef<TypeSourceInfo *> typeArgs,
                                  SourceRange typeArgsRange, bool failOnError,
                                  bool rebuilding) {
  // We can only apply type arguments to an Objective-C class type.
  const auto *objcObjectType = type->getAs<ObjCObjectType>();
  if (!objcObjectType || !objcObjectType->getInterface()) {
    S.Diag(loc, diag::err_objc_type_args_non_class)
      << type
      << typeArgsRange;
 
    if (failOnError)
      return QualType();
    return type;
  }
 
  // The class type must be parameterized.
  ObjCInterfaceDecl *objcClass = objcObjectType->getInterface();
  ObjCTypeParamList *typeParams = objcClass->getTypeParamList();
  if (!typeParams) {
    S.Diag(loc, diag::err_objc_type_args_non_parameterized_class)
      << objcClass->getDeclName()
      << FixItHint::CreateRemoval(typeArgsRange);
 
    if (failOnError)
      return QualType();
 
    return type;
  }
 
  // The type must not already be specialized.
  if (objcObjectType->isSpecialized()) {
    S.Diag(loc, diag::err_objc_type_args_specialized_class)
      << type
      << FixItHint::CreateRemoval(typeArgsRange);
 
    if (failOnError)
      return QualType();
 
    return type;
  }
 
  // Check the type arguments.
  SmallVector<QualType, 4> finalTypeArgs;
  unsigned numTypeParams = typeParams->size();
  bool anyPackExpansions = false;
  for (unsigned i = 0, n = typeArgs.size(); i != n; ++i) {
    TypeSourceInfo *typeArgInfo = typeArgs[i];
    QualType typeArg = typeArgInfo->getType();
 
    // Type arguments cannot have explicit qualifiers or nullability.
    // We ignore indirect sources of these, e.g. behind typedefs or
    // template arguments.
    if (TypeLoc qual = typeArgInfo->getTypeLoc().findExplicitQualifierLoc()) {
      bool diagnosed = false;
      SourceRange rangeToRemove;
      if (auto attr = qual.getAs<AttributedTypeLoc>()) {
        rangeToRemove = attr.getLocalSourceRange();
        if (attr.getTypePtr()->getImmediateNullability()) {
          typeArg = attr.getTypePtr()->getModifiedType();
          S.Diag(attr.getBeginLoc(),
                 diag::err_objc_type_arg_explicit_nullability)
              << typeArg << FixItHint::CreateRemoval(rangeToRemove);
          diagnosed = true;
        }
      }
 
      // When rebuilding, qualifiers might have gotten here through a
      // final substitution.
      if (!rebuilding && !diagnosed) {
        S.Diag(qual.getBeginLoc(), diag::err_objc_type_arg_qualified)
            << typeArg << typeArg.getQualifiers().getAsString()
            << FixItHint::CreateRemoval(rangeToRemove);
      }
    }
 
    // Remove qualifiers even if they're non-local.
    typeArg = typeArg.getUnqualifiedType();
 
    finalTypeArgs.push_back(typeArg);
 
    if (typeArg->getAs<PackExpansionType>())
      anyPackExpansions = true;
 
    // Find the corresponding type parameter, if there is one.
    ObjCTypeParamDecl *typeParam = nullptr;
    if (!anyPackExpansions) {
      if (i < numTypeParams) {
        typeParam = typeParams->begin()[i];
      } else {
        // Too many arguments.
        S.Diag(loc, diag::err_objc_type_args_wrong_arity)
          << false
          << objcClass->getDeclName()
          << (unsigned)typeArgs.size()
          << numTypeParams;
        S.Diag(objcClass->getLocation(), diag::note_previous_decl)
          << objcClass;
 
        if (failOnError)
          return QualType();
 
        return type;
      }
    }
 
    // Objective-C object pointer types must be substitutable for the bounds.
    if (const auto *typeArgObjC = typeArg->getAs<ObjCObjectPointerType>()) {
      // If we don't have a type parameter to match against, assume
      // everything is fine. There was a prior pack expansion that
      // means we won't be able to match anything.
      if (!typeParam) {
        assert(anyPackExpansions && "Too many arguments?");
        continue;
      }
 
      // Retrieve the bound.
      QualType bound = typeParam->getUnderlyingType();
      const auto *boundObjC = bound->getAs<ObjCObjectPointerType>();
 
      // Determine whether the type argument is substitutable for the bound.
      if (typeArgObjC->isObjCIdType()) {
        // When the type argument is 'id', the only acceptable type
        // parameter bound is 'id'.
        if (boundObjC->isObjCIdType())
          continue;
      } else if (S.Context.canAssignObjCInterfaces(boundObjC, typeArgObjC)) {
        // Otherwise, we follow the assignability rules.
        continue;
      }
 
      // Diagnose the mismatch.
      S.Diag(typeArgInfo->getTypeLoc().getBeginLoc(),
             diag::err_objc_type_arg_does_not_match_bound)
          << typeArg << bound << typeParam->getDeclName();
      S.Diag(typeParam->getLocation(), diag::note_objc_type_param_here)
        << typeParam->getDeclName();
 
      if (failOnError)
        return QualType();
 
      return type;
    }
 
    // Block pointer types are permitted for unqualified 'id' bounds.
    if (typeArg->isBlockPointerType()) {
      // If we don't have a type parameter to match against, assume
      // everything is fine. There was a prior pack expansion that
      // means we won't be able to match anything.
      if (!typeParam) {
        assert(anyPackExpansions && "Too many arguments?");
        continue;
      }
 
      // Retrieve the bound.
      QualType bound = typeParam->getUnderlyingType();
      if (bound->isBlockCompatibleObjCPointerType(S.Context))
        continue;
 
      // Diagnose the mismatch.
      S.Diag(typeArgInfo->getTypeLoc().getBeginLoc(),
             diag::err_objc_type_arg_does_not_match_bound)
          << typeArg << bound << typeParam->getDeclName();
      S.Diag(typeParam->getLocation(), diag::note_objc_type_param_here)
        << typeParam->getDeclName();
 
      if (failOnError)
        return QualType();
 
      return type;
    }
 
    // Dependent types will be checked at instantiation time.
    if (typeArg->isDependentType()) {
      continue;
    }
 
    // Diagnose non-id-compatible type arguments.
    S.Diag(typeArgInfo->getTypeLoc().getBeginLoc(),
           diag::err_objc_type_arg_not_id_compatible)
        << typeArg << typeArgInfo->getTypeLoc().getSourceRange();
 
    if (failOnError)
      return QualType();
 
    return type;
  }
 
  // Make sure we didn't have the wrong number of arguments.
  if (!anyPackExpansions && finalTypeArgs.size() != numTypeParams) {
    S.Diag(loc, diag::err_objc_type_args_wrong_arity)
      << (typeArgs.size() < typeParams->size())
      << objcClass->getDeclName()
      << (unsigned)finalTypeArgs.size()
      << (unsigned)numTypeParams;
    S.Diag(objcClass->getLocation(), diag::note_previous_decl)
      << objcClass;
 
    if (failOnError)
      return QualType();
 
    return type;
  }
 
  // Success. Form the specialized type.
  return S.Context.getObjCObjectType(type, finalTypeArgs, { }, false);
}
 
QualType Sema::BuildObjCTypeParamType(const ObjCTypeParamDecl *Decl,
                                      SourceLocation ProtocolLAngleLoc,
                                      ArrayRef<ObjCProtocolDecl *> Protocols,
                                      ArrayRef<SourceLocation> ProtocolLocs,
                                      SourceLocation ProtocolRAngleLoc,
                                      bool FailOnError) {
  QualType Result = QualType(Decl->getTypeForDecl(), 0);
  if (!Protocols.empty()) {
    bool HasError;
    Result = Context.applyObjCProtocolQualifiers(Result, Protocols,
                                                 HasError);
    if (HasError) {
      Diag(SourceLocation(), diag::err_invalid_protocol_qualifiers)
        << SourceRange(ProtocolLAngleLoc, ProtocolRAngleLoc);
      if (FailOnError) Result = QualType();
    }
    if (FailOnError && Result.isNull())
      return QualType();
  }
 
  return Result;
}
 
QualType Sema::BuildObjCObjectType(
    QualType BaseType, SourceLocation Loc, SourceLocation TypeArgsLAngleLoc,
    ArrayRef<TypeSourceInfo *> TypeArgs, SourceLocation TypeArgsRAngleLoc,
    SourceLocation ProtocolLAngleLoc, ArrayRef<ObjCProtocolDecl *> Protocols,
    ArrayRef<SourceLocation> ProtocolLocs, SourceLocation ProtocolRAngleLoc,
    bool FailOnError, bool Rebuilding) {
  QualType Result = BaseType;
  if (!TypeArgs.empty()) {
    Result =
        applyObjCTypeArgs(*this, Loc, Result, TypeArgs,
                          SourceRange(TypeArgsLAngleLoc, TypeArgsRAngleLoc),
                          FailOnError, Rebuilding);
    if (FailOnError && Result.isNull())
      return QualType();
  }
 
  if (!Protocols.empty()) {
    bool HasError;
    Result = Context.applyObjCProtocolQualifiers(Result, Protocols,
                                                 HasError);
    if (HasError) {
      Diag(Loc, diag::err_invalid_protocol_qualifiers)
        << SourceRange(ProtocolLAngleLoc, ProtocolRAngleLoc);
      if (FailOnError) Result = QualType();
    }
    if (FailOnError && Result.isNull())
      return QualType();
  }
 
  return Result;
}
 
TypeResult Sema::actOnObjCProtocolQualifierType(
             SourceLocation lAngleLoc,
             ArrayRef<Decl *> protocols,
             ArrayRef<SourceLocation> protocolLocs,
             SourceLocation rAngleLoc) {
  // Form id<protocol-list>.
  QualType Result = Context.getObjCObjectType(
      Context.ObjCBuiltinIdTy, {},
      llvm::ArrayRef((ObjCProtocolDecl *const *)protocols.data(),
                     protocols.size()),
      false);
  Result = Context.getObjCObjectPointerType(Result);
 
  TypeSourceInfo *ResultTInfo = Context.CreateTypeSourceInfo(Result);
  TypeLoc ResultTL = ResultTInfo->getTypeLoc();
 
  auto ObjCObjectPointerTL = ResultTL.castAs<ObjCObjectPointerTypeLoc>();
  ObjCObjectPointerTL.setStarLoc(SourceLocation()); // implicit
 
  auto ObjCObjectTL = ObjCObjectPointerTL.getPointeeLoc()
                        .castAs<ObjCObjectTypeLoc>();
  ObjCObjectTL.setHasBaseTypeAsWritten(false);
  ObjCObjectTL.getBaseLoc().initialize(Context, SourceLocation());
 
  // No type arguments.
  ObjCObjectTL.setTypeArgsLAngleLoc(SourceLocation());
  ObjCObjectTL.setTypeArgsRAngleLoc(SourceLocation());
 
  // Fill in protocol qualifiers.
  ObjCObjectTL.setProtocolLAngleLoc(lAngleLoc);
  ObjCObjectTL.setProtocolRAngleLoc(rAngleLoc);
  for (unsigned i = 0, n = protocols.size(); i != n; ++i)
    ObjCObjectTL.setProtocolLoc(i, protocolLocs[i]);
 
  // We're done. Return the completed type to the parser.
  return CreateParsedType(Result, ResultTInfo);
}
 
TypeResult Sema::actOnObjCTypeArgsAndProtocolQualifiers(
             Scope *S,
             SourceLocation Loc,
             ParsedType BaseType,
             SourceLocation TypeArgsLAngleLoc,
             ArrayRef<ParsedType> TypeArgs,
             SourceLocation TypeArgsRAngleLoc,
             SourceLocation ProtocolLAngleLoc,
             ArrayRef<Decl *> Protocols,
             ArrayRef<SourceLocation> ProtocolLocs,
             SourceLocation ProtocolRAngleLoc) {
  TypeSourceInfo *BaseTypeInfo = nullptr;
  QualType T = GetTypeFromParser(BaseType, &BaseTypeInfo);
  if (T.isNull())
    return true;
 
  // Handle missing type-source info.
  if (!BaseTypeInfo)
    BaseTypeInfo = Context.getTrivialTypeSourceInfo(T, Loc);
 
  // Extract type arguments.
  SmallVector<TypeSourceInfo *, 4> ActualTypeArgInfos;
  for (unsigned i = 0, n = TypeArgs.size(); i != n; ++i) {
    TypeSourceInfo *TypeArgInfo = nullptr;
    QualType TypeArg = GetTypeFromParser(TypeArgs[i], &TypeArgInfo);
    if (TypeArg.isNull()) {
      ActualTypeArgInfos.clear();
      break;
    }
 
    assert(TypeArgInfo && "No type source info?");
    ActualTypeArgInfos.push_back(TypeArgInfo);
  }
 
  // Build the object type.
  QualType Result = BuildObjCObjectType(
      T, BaseTypeInfo->getTypeLoc().getSourceRange().getBegin(),
      TypeArgsLAngleLoc, ActualTypeArgInfos, TypeArgsRAngleLoc,
      ProtocolLAngleLoc,
      llvm::ArrayRef((ObjCProtocolDecl *const *)Protocols.data(),
                     Protocols.size()),
      ProtocolLocs, ProtocolRAngleLoc,
      /*FailOnError=*/false,
      /*Rebuilding=*/false);
 
  if (Result == T)
    return BaseType;
 
  // Create source information for this type.
  TypeSourceInfo *ResultTInfo = Context.CreateTypeSourceInfo(Result);
  TypeLoc ResultTL = ResultTInfo->getTypeLoc();
 
  // For id<Proto1, Proto2> or Class<Proto1, Proto2>, we'll have an
  // object pointer type. Fill in source information for it.
  if (auto ObjCObjectPointerTL = ResultTL.getAs<ObjCObjectPointerTypeLoc>()) {
    // The '*' is implicit.
    ObjCObjectPointerTL.setStarLoc(SourceLocation());
    ResultTL = ObjCObjectPointerTL.getPointeeLoc();
  }
 
  if (auto OTPTL = ResultTL.getAs<ObjCTypeParamTypeLoc>()) {
    // Protocol qualifier information.
    if (OTPTL.getNumProtocols() > 0) {
      assert(OTPTL.getNumProtocols() == Protocols.size());
      OTPTL.setProtocolLAngleLoc(ProtocolLAngleLoc);
      OTPTL.setProtocolRAngleLoc(ProtocolRAngleLoc);
      for (unsigned i = 0, n = Protocols.size(); i != n; ++i)
        OTPTL.setProtocolLoc(i, ProtocolLocs[i]);
    }
 
    // We're done. Return the completed type to the parser.
    return CreateParsedType(Result, ResultTInfo);
  }
 
  auto ObjCObjectTL = ResultTL.castAs<ObjCObjectTypeLoc>();
 
  // Type argument information.
  if (ObjCObjectTL.getNumTypeArgs() > 0) {
    assert(ObjCObjectTL.getNumTypeArgs() == ActualTypeArgInfos.size());
    ObjCObjectTL.setTypeArgsLAngleLoc(TypeArgsLAngleLoc);
    ObjCObjectTL.setTypeArgsRAngleLoc(TypeArgsRAngleLoc);
    for (unsigned i = 0, n = ActualTypeArgInfos.size(); i != n; ++i)
      ObjCObjectTL.setTypeArgTInfo(i, ActualTypeArgInfos[i]);
  } else {
    ObjCObjectTL.setTypeArgsLAngleLoc(SourceLocation());
    ObjCObjectTL.setTypeArgsRAngleLoc(SourceLocation());
  }
 
  // Protocol qualifier information.
  if (ObjCObjectTL.getNumProtocols() > 0) {
    assert(ObjCObjectTL.getNumProtocols() == Protocols.size());
    ObjCObjectTL.setProtocolLAngleLoc(ProtocolLAngleLoc);
    ObjCObjectTL.setProtocolRAngleLoc(ProtocolRAngleLoc);
    for (unsigned i = 0, n = Protocols.size(); i != n; ++i)
      ObjCObjectTL.setProtocolLoc(i, ProtocolLocs[i]);
  } else {
    ObjCObjectTL.setProtocolLAngleLoc(SourceLocation());
    ObjCObjectTL.setProtocolRAngleLoc(SourceLocation());
  }
 
  // Base type.
  ObjCObjectTL.setHasBaseTypeAsWritten(true);
  if (ObjCObjectTL.getType() == T)
    ObjCObjectTL.getBaseLoc().initializeFullCopy(BaseTypeInfo->getTypeLoc());
  else
    ObjCObjectTL.getBaseLoc().initialize(Context, Loc);
 
  // We're done. Return the completed type to the parser.
  return CreateParsedType(Result, ResultTInfo);
}
 
static OpenCLAccessAttr::Spelling
getImageAccess(const ParsedAttributesView &Attrs) {
  for (const ParsedAttr &AL : Attrs)
    if (AL.getKind() == ParsedAttr::AT_OpenCLAccess)
      return static_cast<OpenCLAccessAttr::Spelling>(AL.getSemanticSpelling());
  return OpenCLAccessAttr::Keyword_read_only;
}
 
static UnaryTransformType::UTTKind
TSTToUnaryTransformType(DeclSpec::TST SwitchTST) {
  switch (SwitchTST) {
#define TRANSFORM_TYPE_TRAIT_DEF(Enum, Trait)                                  \
  case TST_##Trait:                                                            \
    return UnaryTransformType::Enum;
#include "clang/Basic/TransformTypeTraits.def"
  default:
    llvm_unreachable("attempted to parse a non-unary transform builtin");
  }
}
 
/// Convert the specified declspec to the appropriate type
/// object.
/// \param state Specifies the declarator containing the declaration specifier
/// to be converted, along with other associated processing state.
/// \returns The type described by the declaration specifiers.  This function
/// never returns null.
static QualType ConvertDeclSpecToType(TypeProcessingState &state) {
  // FIXME: Should move the logic from DeclSpec::Finish to here for validity
  // checking.
 
  Sema &S = state.getSema();
  Declarator &declarator = state.getDeclarator();
  DeclSpec &DS = declarator.getMutableDeclSpec();
  SourceLocation DeclLoc = declarator.getIdentifierLoc();
  if (DeclLoc.isInvalid())
    DeclLoc = DS.getBeginLoc();
 
  ASTContext &Context = S.Context;
 
  QualType Result;
  switch (DS.getTypeSpecType()) {
  case DeclSpec::TST_void:
    Result = Context.VoidTy;
    break;
  case DeclSpec::TST_char:
    if (DS.getTypeSpecSign() == TypeSpecifierSign::Unspecified)
      Result = Context.CharTy;
    else if (DS.getTypeSpecSign() == TypeSpecifierSign::Signed)
      Result = Context.SignedCharTy;
    else {
      assert(DS.getTypeSpecSign() == TypeSpecifierSign::Unsigned &&
             "Unknown TSS value");
      Result = Context.UnsignedCharTy;
    }
    break;
  case DeclSpec::TST_wchar:
    if (DS.getTypeSpecSign() == TypeSpecifierSign::Unspecified)
      Result = Context.WCharTy;
    else if (DS.getTypeSpecSign() == TypeSpecifierSign::Signed) {
      S.Diag(DS.getTypeSpecSignLoc(), diag::ext_wchar_t_sign_spec)
        << DS.getSpecifierName(DS.getTypeSpecType(),
                               Context.getPrintingPolicy());
      Result = Context.getSignedWCharType();
    } else {
      assert(DS.getTypeSpecSign() == TypeSpecifierSign::Unsigned &&
             "Unknown TSS value");
      S.Diag(DS.getTypeSpecSignLoc(), diag::ext_wchar_t_sign_spec)
        << DS.getSpecifierName(DS.getTypeSpecType(),
                               Context.getPrintingPolicy());
      Result = Context.getUnsignedWCharType();
    }
    break;
  case DeclSpec::TST_char8:
    assert(DS.getTypeSpecSign() == TypeSpecifierSign::Unspecified &&
           "Unknown TSS value");
    Result = Context.Char8Ty;
    break;
  case DeclSpec::TST_char16:
    assert(DS.getTypeSpecSign() == TypeSpecifierSign::Unspecified &&
           "Unknown TSS value");
    Result = Context.Char16Ty;
    break;
  case DeclSpec::TST_char32:
    assert(DS.getTypeSpecSign() == TypeSpecifierSign::Unspecified &&
           "Unknown TSS value");
    Result = Context.Char32Ty;
    break;
  case DeclSpec::TST_unspecified:
    // If this is a missing declspec in a block literal return context, then it
    // is inferred from the return statements inside the block.
    // The declspec is always missing in a lambda expr context; it is either
    // specified with a trailing return type or inferred.
    if (S.getLangOpts().CPlusPlus14 &&
        declarator.getContext() == DeclaratorContext::LambdaExpr) {
      // In C++1y, a lambda's implicit return type is 'auto'.
      Result = Context.getAutoDeductType();
      break;
    } else if (declarator.getContext() == DeclaratorContext::LambdaExpr ||
               checkOmittedBlockReturnType(S, declarator,
                                           Context.DependentTy)) {
      Result = Context.DependentTy;
      break;
    }
 
    // Unspecified typespec defaults to int in C90.  However, the C90 grammar
    // [C90 6.5] only allows a decl-spec if there was *some* type-specifier,
    // type-qualifier, or storage-class-specifier.  If not, emit an extwarn.
    // Note that the one exception to this is function definitions, which are
    // allowed to be completely missing a declspec.  This is handled in the
    // parser already though by it pretending to have seen an 'int' in this
    // case.
    if (S.getLangOpts().isImplicitIntRequired()) {
      S.Diag(DeclLoc, diag::warn_missing_type_specifier)
          << DS.getSourceRange()
          << FixItHint::CreateInsertion(DS.getBeginLoc(), "int");
    } else if (!DS.hasTypeSpecifier()) {
      // C99 and C++ require a type specifier.  For example, C99 6.7.2p2 says:
      // "At least one type specifier shall be given in the declaration
      // specifiers in each declaration, and in the specifier-qualifier list in
      // each struct declaration and type name."
      if (!S.getLangOpts().isImplicitIntAllowed() && !DS.isTypeSpecPipe()) {
        S.Diag(DeclLoc, diag::err_missing_type_specifier)
            << DS.getSourceRange();
 
        // When this occurs, often something is very broken with the value
        // being declared, poison it as invalid so we don't get chains of
        // errors.
        declarator.setInvalidType(true);
      } else if (S.getLangOpts().getOpenCLCompatibleVersion() >= 200 &&
                 DS.isTypeSpecPipe()) {
        S.Diag(DeclLoc, diag::err_missing_actual_pipe_type)
            << DS.getSourceRange();
        declarator.setInvalidType(true);
      } else {
        assert(S.getLangOpts().isImplicitIntAllowed() &&
               "implicit int is disabled?");
        S.Diag(DeclLoc, diag::ext_missing_type_specifier)
            << DS.getSourceRange()
            << FixItHint::CreateInsertion(DS.getBeginLoc(), "int");
      }
    }
 
    [[fallthrough]];
  case DeclSpec::TST_int: {
    if (DS.getTypeSpecSign() != TypeSpecifierSign::Unsigned) {
      switch (DS.getTypeSpecWidth()) {
      case TypeSpecifierWidth::Unspecified:
        Result = Context.IntTy;
        break;
      case TypeSpecifierWidth::Short:
        Result = Context.ShortTy;
        break;
      case TypeSpecifierWidth::Long:
        Result = Context.LongTy;
        break;
      case TypeSpecifierWidth::LongLong:
        Result = Context.LongLongTy;
 
        // 'long long' is a C99 or C++11 feature.
        if (!S.getLangOpts().C99) {
          if (S.getLangOpts().CPlusPlus)
            S.Diag(DS.getTypeSpecWidthLoc(),
                   S.getLangOpts().CPlusPlus11 ?
                   diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
          else
            S.Diag(DS.getTypeSpecWidthLoc(), diag::ext_c99_longlong);
        }
        break;
      }
    } else {
      switch (DS.getTypeSpecWidth()) {
      case TypeSpecifierWidth::Unspecified:
        Result = Context.UnsignedIntTy;
        break;
      case TypeSpecifierWidth::Short:
        Result = Context.UnsignedShortTy;
        break;
      case TypeSpecifierWidth::Long:
        Result = Context.UnsignedLongTy;
        break;
      case TypeSpecifierWidth::LongLong:
        Result = Context.UnsignedLongLongTy;
 
        // 'long long' is a C99 or C++11 feature.
        if (!S.getLangOpts().C99) {
          if (S.getLangOpts().CPlusPlus)
            S.Diag(DS.getTypeSpecWidthLoc(),
                   S.getLangOpts().CPlusPlus11 ?
                   diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
          else
            S.Diag(DS.getTypeSpecWidthLoc(), diag::ext_c99_longlong);
        }
        break;
      }
    }
    break;
  }
  case DeclSpec::TST_bitint: {
    if (!S.Context.getTargetInfo().hasBitIntType())
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported) << "_BitInt";
    Result =
        S.BuildBitIntType(DS.getTypeSpecSign() == TypeSpecifierSign::Unsigned,
                          DS.getRepAsExpr(), DS.getBeginLoc());
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;
  }
  case DeclSpec::TST_accum: {
    switch (DS.getTypeSpecWidth()) {
    case TypeSpecifierWidth::Short:
      Result = Context.ShortAccumTy;
      break;
    case TypeSpecifierWidth::Unspecified:
      Result = Context.AccumTy;
      break;
    case TypeSpecifierWidth::Long:
      Result = Context.LongAccumTy;
      break;
    case TypeSpecifierWidth::LongLong:
      llvm_unreachable("Unable to specify long long as _Accum width");
    }
 
    if (DS.getTypeSpecSign() == TypeSpecifierSign::Unsigned)
      Result = Context.getCorrespondingUnsignedType(Result);
 
    if (DS.isTypeSpecSat())
      Result = Context.getCorrespondingSaturatedType(Result);
 
    break;
  }
  case DeclSpec::TST_fract: {
    switch (DS.getTypeSpecWidth()) {
    case TypeSpecifierWidth::Short:
      Result = Context.ShortFractTy;
      break;
    case TypeSpecifierWidth::Unspecified:
      Result = Context.FractTy;
      break;
    case TypeSpecifierWidth::Long:
      Result = Context.LongFractTy;
      break;
    case TypeSpecifierWidth::LongLong:
      llvm_unreachable("Unable to specify long long as _Fract width");
    }
 
    if (DS.getTypeSpecSign() == TypeSpecifierSign::Unsigned)
      Result = Context.getCorrespondingUnsignedType(Result);
 
    if (DS.isTypeSpecSat())
      Result = Context.getCorrespondingSaturatedType(Result);
 
    break;
  }
  case DeclSpec::TST_int128:
    if (!S.Context.getTargetInfo().hasInt128Type() &&
        !(S.getLangOpts().SYCLIsDevice || S.getLangOpts().CUDAIsDevice ||
          (S.getLangOpts().OpenMP && S.getLangOpts().OpenMPIsDevice)))
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
        << "__int128";
    if (DS.getTypeSpecSign() == TypeSpecifierSign::Unsigned)
      Result = Context.UnsignedInt128Ty;
    else
      Result = Context.Int128Ty;
    break;
  case DeclSpec::TST_float16:
    // CUDA host and device may have different _Float16 support, therefore
    // do not diagnose _Float16 usage to avoid false alarm.
    // ToDo: more precise diagnostics for CUDA.
    if (!S.Context.getTargetInfo().hasFloat16Type() && !S.getLangOpts().CUDA &&
        !(S.getLangOpts().OpenMP && S.getLangOpts().OpenMPIsDevice))
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
        << "_Float16";
    Result = Context.Float16Ty;
    break;
  case DeclSpec::TST_half:    Result = Context.HalfTy; break;
  case DeclSpec::TST_BFloat16:
    if (!S.Context.getTargetInfo().hasBFloat16Type() &&
        !(S.getLangOpts().OpenMP && S.getLangOpts().OpenMPIsDevice) &&
        !S.getLangOpts().SYCLIsDevice)
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported) << "__bf16";
    Result = Context.BFloat16Ty;
    break;
  case DeclSpec::TST_float:   Result = Context.FloatTy; break;
  case DeclSpec::TST_double:
    if (DS.getTypeSpecWidth() == TypeSpecifierWidth::Long)
      Result = Context.LongDoubleTy;
    else
      Result = Context.DoubleTy;
    if (S.getLangOpts().OpenCL) {
      if (!S.getOpenCLOptions().isSupported("cl_khr_fp64", S.getLangOpts()))
        S.Diag(DS.getTypeSpecTypeLoc(), diag::err_opencl_requires_extension)
            << 0 << Result
            << (S.getLangOpts().getOpenCLCompatibleVersion() == 300
                    ? "cl_khr_fp64 and __opencl_c_fp64"
                    : "cl_khr_fp64");
      else if (!S.getOpenCLOptions().isAvailableOption("cl_khr_fp64", S.getLangOpts()))
        S.Diag(DS.getTypeSpecTypeLoc(), diag::ext_opencl_double_without_pragma);
    }
    break;
  case DeclSpec::TST_float128:
    if (!S.Context.getTargetInfo().hasFloat128Type() &&
        !S.getLangOpts().SYCLIsDevice &&
        !(S.getLangOpts().OpenMP && S.getLangOpts().OpenMPIsDevice))
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
        << "__float128";
    Result = Context.Float128Ty;
    break;
  case DeclSpec::TST_ibm128:
    if (!S.Context.getTargetInfo().hasIbm128Type() &&
        !S.getLangOpts().SYCLIsDevice &&
        !(S.getLangOpts().OpenMP && S.getLangOpts().OpenMPIsDevice))
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported) << "__ibm128";
    Result = Context.Ibm128Ty;
    break;
  case DeclSpec::TST_bool:
    Result = Context.BoolTy; // _Bool or bool
    break;
  case DeclSpec::TST_decimal32:    // _Decimal32
  case DeclSpec::TST_decimal64:    // _Decimal64
  case DeclSpec::TST_decimal128:   // _Decimal128
    S.Diag(DS.getTypeSpecTypeLoc(), diag::err_decimal_unsupported);
    Result = Context.IntTy;
    declarator.setInvalidType(true);
    break;
  case DeclSpec::TST_class:
  case DeclSpec::TST_enum:
  case DeclSpec::TST_union:
  case DeclSpec::TST_struct:
  case DeclSpec::TST_interface: {
    TagDecl *D = dyn_cast_or_null<TagDecl>(DS.getRepAsDecl());
    if (!D) {
      // This can happen in C++ with ambiguous lookups.
      Result = Context.IntTy;
      declarator.setInvalidType(true);
      break;
    }
 
    // If the type is deprecated or unavailable, diagnose it.
    S.DiagnoseUseOfDecl(D, DS.getTypeSpecTypeNameLoc());
 
    assert(DS.getTypeSpecWidth() == TypeSpecifierWidth::Unspecified &&
           DS.getTypeSpecComplex() == 0 &&
           DS.getTypeSpecSign() == TypeSpecifierSign::Unspecified &&
           "No qualifiers on tag names!");
 
    // TypeQuals handled by caller.
    Result = Context.getTypeDeclType(D);
 
    // In both C and C++, make an ElaboratedType.
    ElaboratedTypeKeyword Keyword
      = ElaboratedType::getKeywordForTypeSpec(DS.getTypeSpecType());
    Result = S.getElaboratedType(Keyword, DS.getTypeSpecScope(), Result,
                                 DS.isTypeSpecOwned() ? D : nullptr);
    break;
  }
  case DeclSpec::TST_typename: {
    assert(DS.getTypeSpecWidth() == TypeSpecifierWidth::Unspecified &&
           DS.getTypeSpecComplex() == 0 &&
           DS.getTypeSpecSign() == TypeSpecifierSign::Unspecified &&
           "Can't handle qualifiers on typedef names yet!");
    Result = S.GetTypeFromParser(DS.getRepAsType());
    if (Result.isNull()) {
      declarator.setInvalidType(true);
    }
 
    // TypeQuals handled by caller.
    break;
  }
  case DeclSpec::TST_typeof_unqualType:
  case DeclSpec::TST_typeofType:
    // FIXME: Preserve type source info.
    Result = S.GetTypeFromParser(DS.getRepAsType());
    assert(!Result.isNull() && "Didn't get a type for typeof?");
    if (!Result->isDependentType())
      if (const TagType *TT = Result->getAs<TagType>())
        S.DiagnoseUseOfDecl(TT->getDecl(), DS.getTypeSpecTypeLoc());
    // TypeQuals handled by caller.
    Result = Context.getTypeOfType(
        Result, DS.getTypeSpecType() == DeclSpec::TST_typeof_unqualType
                    ? TypeOfKind::Unqualified
                    : TypeOfKind::Qualified);
    break;
  case DeclSpec::TST_typeof_unqualExpr:
  case DeclSpec::TST_typeofExpr: {
    Expr *E = DS.getRepAsExpr();
    assert(E && "Didn't get an expression for typeof?");
    // TypeQuals handled by caller.
    Result = S.BuildTypeofExprType(E, DS.getTypeSpecType() ==
                                              DeclSpec::TST_typeof_unqualExpr
                                          ? TypeOfKind::Unqualified
                                          : TypeOfKind::Qualified);
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;
  }
  case DeclSpec::TST_decltype: {
    Expr *E = DS.getRepAsExpr();
    assert(E && "Didn't get an expression for decltype?");
    // TypeQuals handled by caller.
    Result = S.BuildDecltypeType(E);
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;
  }
#define TRANSFORM_TYPE_TRAIT_DEF(_, Trait) case DeclSpec::TST_##Trait:
#include "clang/Basic/TransformTypeTraits.def"
    Result = S.GetTypeFromParser(DS.getRepAsType());
    assert(!Result.isNull() && "Didn't get a type for the transformation?");
    Result = S.BuildUnaryTransformType(
        Result, TSTToUnaryTransformType(DS.getTypeSpecType()),
        DS.getTypeSpecTypeLoc());
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;
 
  case DeclSpec::TST_auto:
  case DeclSpec::TST_decltype_auto: {
    auto AutoKW = DS.getTypeSpecType() == DeclSpec::TST_decltype_auto
                      ? AutoTypeKeyword::DecltypeAuto
                      : AutoTypeKeyword::Auto;
 
    ConceptDecl *TypeConstraintConcept = nullptr;
    llvm::SmallVector<TemplateArgument, 8> TemplateArgs;
    if (DS.isConstrainedAuto()) {
      if (TemplateIdAnnotation *TemplateId = DS.getRepAsTemplateId()) {
        TypeConstraintConcept =
            cast<ConceptDecl>(TemplateId->Template.get().getAsTemplateDecl());
        TemplateArgumentListInfo TemplateArgsInfo;
        TemplateArgsInfo.setLAngleLoc(TemplateId->LAngleLoc);
        TemplateArgsInfo.setRAngleLoc(TemplateId->RAngleLoc);
        ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
                                           TemplateId->NumArgs);
        S.translateTemplateArguments(TemplateArgsPtr, TemplateArgsInfo);
        for (const auto &ArgLoc : TemplateArgsInfo.arguments())
          TemplateArgs.push_back(ArgLoc.getArgument());
      } else {
        declarator.setInvalidType(true);
      }
    }
    Result = S.Context.getAutoType(QualType(), AutoKW,
                                   /*IsDependent*/ false, /*IsPack=*/false,
                                   TypeConstraintConcept, TemplateArgs);
    break;
  }
 
  case DeclSpec::TST_auto_type:
    Result = Context.getAutoType(QualType(), AutoTypeKeyword::GNUAutoType, false);
    break;
 
  case DeclSpec::TST_unknown_anytype:
    Result = Context.UnknownAnyTy;
    break;
 
  case DeclSpec::TST_atomic:
    Result = S.GetTypeFromParser(DS.getRepAsType());
    assert(!Result.isNull() && "Didn't get a type for _Atomic?");
    Result = S.BuildAtomicType(Result, DS.getTypeSpecTypeLoc());
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;
 
#define GENERIC_IMAGE_TYPE(ImgType, Id)                                        \
  case DeclSpec::TST_##ImgType##_t:                                            \
    switch (getImageAccess(DS.getAttributes())) {                              \
    case OpenCLAccessAttr::Keyword_write_only:                                 \
      Result = Context.Id##WOTy;                                               \
      break;                                                                   \
    case OpenCLAccessAttr::Keyword_read_write:                                 \
      Result = Context.Id##RWTy;                                               \
      break;                                                                   \
    case OpenCLAccessAttr::Keyword_read_only:                                  \
      Result = Context.Id##ROTy;                                               \
      break;                                                                   \
    case OpenCLAccessAttr::SpellingNotCalculated:                              \
      llvm_unreachable("Spelling not yet calculated");                         \
    }                                                                          \
    break;
#include "clang/Basic/OpenCLImageTypes.def"
 
  case DeclSpec::TST_error:
    Result = Context.IntTy;
    declarator.setInvalidType(true);
    break;
  }
 
  // FIXME: we want resulting declarations to be marked invalid, but claiming
  // the type is invalid is too strong - e.g. it causes ActOnTypeName to return
  // a null type.
  if (Result->containsErrors())
    declarator.setInvalidType();
 
  if (S.getLangOpts().OpenCL) {
    const auto &OpenCLOptions = S.getOpenCLOptions();
    bool IsOpenCLC30Compatible =
        S.getLangOpts().getOpenCLCompatibleVersion() == 300;
    // OpenCL C v3.0 s6.3.3 - OpenCL image types require __opencl_c_images
    // support.
    // OpenCL C v3.0 s6.2.1 - OpenCL 3d image write types requires support
    // for OpenCL C 2.0, or OpenCL C 3.0 or newer and the
    // __opencl_c_3d_image_writes feature. OpenCL C v3.0 API s4.2 - For devices
    // that support OpenCL 3.0, cl_khr_3d_image_writes must be returned when and
    // only when the optional feature is supported
    if ((Result->isImageType() || Result->isSamplerT()) &&
        (IsOpenCLC30Compatible &&
         !OpenCLOptions.isSupported("__opencl_c_images", S.getLangOpts()))) {
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_opencl_requires_extension)
          << 0 << Result << "__opencl_c_images";
      declarator.setInvalidType();
    } else if (Result->isOCLImage3dWOType() &&
               !OpenCLOptions.isSupported("cl_khr_3d_image_writes",
                                          S.getLangOpts())) {
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_opencl_requires_extension)
          << 0 << Result
          << (IsOpenCLC30Compatible
                  ? "cl_khr_3d_image_writes and __opencl_c_3d_image_writes"
                  : "cl_khr_3d_image_writes");
      declarator.setInvalidType();
    }
  }
 
  bool IsFixedPointType = DS.getTypeSpecType() == DeclSpec::TST_accum ||
                          DS.getTypeSpecType() == DeclSpec::TST_fract;
 
  // Only fixed point types can be saturated
  if (DS.isTypeSpecSat() && !IsFixedPointType)
    S.Diag(DS.getTypeSpecSatLoc(), diag::err_invalid_saturation_spec)
        << DS.getSpecifierName(DS.getTypeSpecType(),
                               Context.getPrintingPolicy());
 
  // Handle complex types.
  if (DS.getTypeSpecComplex() == DeclSpec::TSC_complex) {
    if (S.getLangOpts().Freestanding)
      S.Diag(DS.getTypeSpecComplexLoc(), diag::ext_freestanding_complex);
    Result = Context.getComplexType(Result);
  } else if (DS.isTypeAltiVecVector()) {
    unsigned typeSize = static_cast<unsigned>(Context.getTypeSize(Result));
    assert(typeSize > 0 && "type size for vector must be greater than 0 bits");
    VectorType::VectorKind VecKind = VectorType::AltiVecVector;
    if (DS.isTypeAltiVecPixel())
      VecKind = VectorType::AltiVecPixel;
    else if (DS.isTypeAltiVecBool())
      VecKind = VectorType::AltiVecBool;
    Result = Context.getVectorType(Result, 128/typeSize, VecKind);
  }
 
  // FIXME: Imaginary.
  if (DS.getTypeSpecComplex() == DeclSpec::TSC_imaginary)
    S.Diag(DS.getTypeSpecComplexLoc(), diag::err_imaginary_not_supported);
 
  // Before we process any type attributes, synthesize a block literal
  // function declarator if necessary.
  if (declarator.getContext() == DeclaratorContext::BlockLiteral)
    maybeSynthesizeBlockSignature(state, Result);
 
  // Apply any type attributes from the decl spec.  This may cause the
  // list of type attributes to be temporarily saved while the type
  // attributes are pushed around.
  // pipe attributes will be handled later ( at GetFullTypeForDeclarator )
  if (!DS.isTypeSpecPipe()) {
    // We also apply declaration attributes that "slide" to the decl spec.
    // Ordering can be important for attributes. The decalaration attributes
    // come syntactically before the decl spec attributes, so we process them
    // in that order.
    ParsedAttributesView SlidingAttrs;
    for (ParsedAttr &AL : declarator.getDeclarationAttributes()) {
      if (AL.slidesFromDeclToDeclSpecLegacyBehavior()) {
        SlidingAttrs.addAtEnd(&AL);
 
        // For standard syntax attributes, which would normally appertain to the
        // declaration here, suggest moving them to the type instead. But only
        // do this for our own vendor attributes; moving other vendors'
        // attributes might hurt portability.
        // There's one special case that we need to deal with here: The
        // `MatrixType` attribute may only be used in a typedef declaration. If
        // it's being used anywhere else, don't output the warning as
        // ProcessDeclAttributes() will output an error anyway.
        if (AL.isStandardAttributeSyntax() && AL.isClangScope() &&
            !(AL.getKind() == ParsedAttr::AT_MatrixType &&
              DS.getStorageClassSpec() != DeclSpec::SCS_typedef)) {
          S.Diag(AL.getLoc(), diag::warn_type_attribute_deprecated_on_decl)
              << AL;
        }
      }
    }
    // During this call to processTypeAttrs(),
    // TypeProcessingState::getCurrentAttributes() will erroneously return a
    // reference to the DeclSpec attributes, rather than the declaration
    // attributes. However, this doesn't matter, as getCurrentAttributes()
    // is only called when distributing attributes from one attribute list
    // to another. Declaration attributes are always C++11 attributes, and these
    // are never distributed.
    processTypeAttrs(state, Result, TAL_DeclSpec, SlidingAttrs);
    processTypeAttrs(state, Result, TAL_DeclSpec, DS.getAttributes());
  }
 
  // Apply const/volatile/restrict qualifiers to T.
  if (unsigned TypeQuals = DS.getTypeQualifiers()) {
    // Warn about CV qualifiers on function types.
    // C99 6.7.3p8:
    //   If the specification of a function type includes any type qualifiers,
    //   the behavior is undefined.
    // C++11 [dcl.fct]p7:
    //   The effect of a cv-qualifier-seq in a function declarator is not the
    //   same as adding cv-qualification on top of the function type. In the
    //   latter case, the cv-qualifiers are ignored.
    if (Result->isFunctionType()) {
      diagnoseAndRemoveTypeQualifiers(
          S, DS, TypeQuals, Result, DeclSpec::TQ_const | DeclSpec::TQ_volatile,
          S.getLangOpts().CPlusPlus
              ? diag::warn_typecheck_function_qualifiers_ignored
              : diag::warn_typecheck_function_qualifiers_unspecified);
      // No diagnostic for 'restrict' or '_Atomic' applied to a
      // function type; we'll diagnose those later, in BuildQualifiedType.
    }
 
    // C++11 [dcl.ref]p1:
    //   Cv-qualified references are ill-formed except when the
    //   cv-qualifiers are introduced through the use of a typedef-name
    //   or decltype-specifier, in which case the cv-qualifiers are ignored.
    //
    // There don't appear to be any other contexts in which a cv-qualified
    // reference type could be formed, so the 'ill-formed' clause here appears
    // to never happen.
    if (TypeQuals && Result->isReferenceType()) {
      diagnoseAndRemoveTypeQualifiers(
          S, DS, TypeQuals, Result,
          DeclSpec::TQ_const | DeclSpec::TQ_volatile | DeclSpec::TQ_atomic,
          diag::warn_typecheck_reference_qualifiers);
    }
 
    // C90 6.5.3 constraints: "The same type qualifier shall not appear more
    // than once in the same specifier-list or qualifier-list, either directly
    // or via one or more typedefs."
    if (!S.getLangOpts().C99 && !S.getLangOpts().CPlusPlus
        && TypeQuals & Result.getCVRQualifiers()) {
      if (TypeQuals & DeclSpec::TQ_const && Result.isConstQualified()) {
        S.Diag(DS.getConstSpecLoc(), diag::ext_duplicate_declspec)
          << "const";
      }
 
      if (TypeQuals & DeclSpec::TQ_volatile && Result.isVolatileQualified()) {
        S.Diag(DS.getVolatileSpecLoc(), diag::ext_duplicate_declspec)
          << "volatile";
      }
 
      // C90 doesn't have restrict nor _Atomic, so it doesn't force us to
      // produce a warning in this case.
    }
 
    QualType Qualified = S.BuildQualifiedType(Result, DeclLoc, TypeQuals, &DS);
 
    // If adding qualifiers fails, just use the unqualified type.
    if (Qualified.isNull())
      declarator.setInvalidType(true);
    else
      Result = Qualified;
  }
 
  assert(!Result.isNull() && "This function should not return a null type");
  return Result;
}
 
static std::string getPrintableNameForEntity(DeclarationName Entity) {
  if (Entity)
    return Entity.getAsString();
 
  return "type name";
}
 
static bool isDependentOrGNUAutoType(QualType T) {
  if (T->isDependentType())
    return true;
 
  const auto *AT = dyn_cast<AutoType>(T);
  return AT && AT->isGNUAutoType();
}
 
QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
                                  Qualifiers Qs, const DeclSpec *DS) {
  if (T.isNull())
    return QualType();
 
  // Ignore any attempt to form a cv-qualified reference.
  if (T->isReferenceType()) {
    Qs.removeConst();
    Qs.removeVolatile();
  }
 
  // Enforce C99 6.7.3p2: "Types other than pointer types derived from
  // object or incomplete types shall not be restrict-qualified."
  if (Qs.hasRestrict()) {
    unsigned DiagID = 0;
    QualType ProblemTy;
 
    if (T->isAnyPointerType() || T->isReferenceType() ||
        T->isMemberPointerType()) {
      QualType EltTy;
      if (T->isObjCObjectPointerType())
        EltTy = T;
      else if (const MemberPointerType *PTy = T->getAs<MemberPointerType>())
        EltTy = PTy->getPointeeType();
      else
        EltTy = T->getPointeeType();
 
      // If we have a pointer or reference, the pointee must have an object
      // incomplete type.
      if (!EltTy->isIncompleteOrObjectType()) {
        DiagID = diag::err_typecheck_invalid_restrict_invalid_pointee;
        ProblemTy = EltTy;
      }
    } else if (!isDependentOrGNUAutoType(T)) {
      // For an __auto_type variable, we may not have seen the initializer yet
      // and so have no idea whether the underlying type is a pointer type or
      // not.
      DiagID = diag::err_typecheck_invalid_restrict_not_pointer;
      ProblemTy = T;
    }
 
    if (DiagID) {
      Diag(DS ? DS->getRestrictSpecLoc() : Loc, DiagID) << ProblemTy;
      Qs.removeRestrict();
    }
  }
 
  return Context.getQualifiedType(T, Qs);
}
 
QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
                                  unsigned CVRAU, const DeclSpec *DS) {
  if (T.isNull())
    return QualType();
 
  // Ignore any attempt to form a cv-qualified reference.
  if (T->isReferenceType())
    CVRAU &=
        ~(DeclSpec::TQ_const | DeclSpec::TQ_volatile | DeclSpec::TQ_atomic);
 
  // Convert from DeclSpec::TQ to Qualifiers::TQ by just dropping TQ_atomic and
  // TQ_unaligned;
  unsigned CVR = CVRAU & ~(DeclSpec::TQ_atomic | DeclSpec::TQ_unaligned);
 
  // C11 6.7.3/5:
  //   If the same qualifier appears more than once in the same
  //   specifier-qualifier-list, either directly or via one or more typedefs,
  //   the behavior is the same as if it appeared only once.
  //
  // It's not specified what happens when the _Atomic qualifier is applied to
  // a type specified with the _Atomic specifier, but we assume that this
  // should be treated as if the _Atomic qualifier appeared multiple times.
  if (CVRAU & DeclSpec::TQ_atomic && !T->isAtomicType()) {
    // C11 6.7.3/5:
    //   If other qualifiers appear along with the _Atomic qualifier in a
    //   specifier-qualifier-list, the resulting type is the so-qualified
    //   atomic type.
    //
    // Don't need to worry about array types here, since _Atomic can't be
    // applied to such types.
    SplitQualType Split = T.getSplitUnqualifiedType();
    T = BuildAtomicType(QualType(Split.Ty, 0),
                        DS ? DS->getAtomicSpecLoc() : Loc);
    if (T.isNull())
      return T;
    Split.Quals.addCVRQualifiers(CVR);
    return BuildQualifiedType(T, Loc, Split.Quals);
  }
 
  Qualifiers Q = Qualifiers::fromCVRMask(CVR);
  Q.setUnaligned(CVRAU & DeclSpec::TQ_unaligned);
  return BuildQualifiedType(T, Loc, Q, DS);
}
 
/// Build a paren type including \p T.
QualType Sema::BuildParenType(QualType T) {
  return Context.getParenType(T);
}
 
/// Given that we're building a pointer or reference to the given
static QualType inferARCLifetimeForPointee(Sema &S, QualType type,
                                           SourceLocation loc,
                                           bool isReference) {
  // Bail out if retention is unrequired or already specified.
  if (!type->isObjCLifetimeType() ||
      type.getObjCLifetime() != Qualifiers::OCL_None)
    return type;
 
  Qualifiers::ObjCLifetime implicitLifetime = Qualifiers::OCL_None;
 
  // If the object type is const-qualified, we can safely use
  // __unsafe_unretained.  This is safe (because there are no read
  // barriers), and it'll be safe to coerce anything but __weak* to
  // the resulting type.
  if (type.isConstQualified()) {
    implicitLifetime = Qualifiers::OCL_ExplicitNone;
 
  // Otherwise, check whether the static type does not require
  // retaining.  This currently only triggers for Class (possibly
  // protocol-qualifed, and arrays thereof).
  } else if (type->isObjCARCImplicitlyUnretainedType()) {
    implicitLifetime = Qualifiers::OCL_ExplicitNone;
 
  // If we are in an unevaluated context, like sizeof, skip adding a
  // qualification.
  } else if (S.isUnevaluatedContext()) {
    return type;
 
  // If that failed, give an error and recover using __strong.  __strong
  // is the option most likely to prevent spurious second-order diagnostics,
  // like when binding a reference to a field.
  } else {
    // These types can show up in private ivars in system headers, so
    // we need this to not be an error in those cases.  Instead we
    // want to delay.
    if (S.DelayedDiagnostics.shouldDelayDiagnostics()) {
      S.DelayedDiagnostics.add(
          sema::DelayedDiagnostic::makeForbiddenType(loc,
              diag::err_arc_indirect_no_ownership, type, isReference));
    } else {
      S.Diag(loc, diag::err_arc_indirect_no_ownership) << type << isReference;
    }
    implicitLifetime = Qualifiers::OCL_Strong;
  }
  assert(implicitLifetime && "didn't infer any lifetime!");
 
  Qualifiers qs;
  qs.addObjCLifetime(implicitLifetime);
  return S.Context.getQualifiedType(type, qs);
}
 
static std::string getFunctionQualifiersAsString(const FunctionProtoType *FnTy){
  std::string Quals = FnTy->getMethodQuals().getAsString();
 
  switch (FnTy->getRefQualifier()) {
  case RQ_None:
    break;
 
  case RQ_LValue:
    if (!Quals.empty())
      Quals += ' ';
    Quals += '&';
    break;
 
  case RQ_RValue:
    if (!Quals.empty())
      Quals += ' ';
    Quals += "&&";
    break;
  }
 
  return Quals;
}
 
namespace {
/// Kinds of declarator that cannot contain a qualified function type.
///
/// C++98 [dcl.fct]p4 / C++11 [dcl.fct]p6:
///     a function type with a cv-qualifier or a ref-qualifier can only appear
///     at the topmost level of a type.
///
/// Parens and member pointers are permitted. We don't diagnose array and
/// function declarators, because they don't allow function types at all.
///
/// The values of this enum are used in diagnostics.
enum QualifiedFunctionKind { QFK_BlockPointer, QFK_Pointer, QFK_Reference };
} // end anonymous namespace
 
/// Check whether the type T is a qualified function type, and if it is,
/// diagnose that it cannot be contained within the given kind of declarator.
static bool checkQualifiedFunction(Sema &S, QualType T, SourceLocation Loc,
                                   QualifiedFunctionKind QFK) {
  // Does T refer to a function type with a cv-qualifier or a ref-qualifier?
  const FunctionProtoType *FPT = T->getAs<FunctionProtoType>();
  if (!FPT ||
      (FPT->getMethodQuals().empty() && FPT->getRefQualifier() == RQ_None))
    return false;
 
  S.Diag(Loc, diag::err_compound_qualified_function_type)
    << QFK << isa<FunctionType>(T.IgnoreParens()) << T
    << getFunctionQualifiersAsString(FPT);
  return true;
}
 
bool Sema::CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc) {
  const FunctionProtoType *FPT = T->getAs<FunctionProtoType>();
  if (!FPT ||
      (FPT->getMethodQuals().empty() && FPT->getRefQualifier() == RQ_None))
    return false;
 
  Diag(Loc, diag::err_qualified_function_typeid)
      << T << getFunctionQualifiersAsString(FPT);
  return true;
}
 
// Helper to deduce addr space of a pointee type in OpenCL mode.
static QualType deduceOpenCLPointeeAddrSpace(Sema &S, QualType PointeeType) {
  if (!PointeeType->isUndeducedAutoType() && !PointeeType->isDependentType() &&
      !PointeeType->isSamplerT() &&
      !PointeeType.hasAddressSpace())
    PointeeType = S.getASTContext().getAddrSpaceQualType(
        PointeeType, S.getASTContext().getDefaultOpenCLPointeeAddrSpace());
  return PointeeType;
}
 
/// Build a pointer type.
///
/// \param T The type to which we'll be building a pointer.
///
/// \param Loc The location of the entity whose type involves this
/// pointer type or, if there is no such entity, the location of the
/// type that will have pointer type.
///
/// \param Entity The name of the entity that involves the pointer
/// type, if known.
///
/// \returns A suitable pointer type, if there are no
/// errors. Otherwise, returns a NULL type.
QualType Sema::BuildPointerType(QualType T,
                                SourceLocation Loc, DeclarationName Entity) {
  if (T->isReferenceType()) {
    // C++ 8.3.2p4: There shall be no ... pointers to references ...
    Diag(Loc, diag::err_illegal_decl_pointer_to_reference)
      << getPrintableNameForEntity(Entity) << T;
    return QualType();
  }
 
  if (T->isFunctionType() && getLangOpts().OpenCL &&
      !getOpenCLOptions().isAvailableOption("__cl_clang_function_pointers",
                                            getLangOpts())) {
    Diag(Loc, diag::err_opencl_function_pointer) << /*pointer*/ 0;
    return QualType();
  }
 
  if (getLangOpts().HLSL && Loc.isValid()) {
    Diag(Loc, diag::err_hlsl_pointers_unsupported) << 0;
    return QualType();
  }
 
  if (checkQualifiedFunction(*this, T, Loc, QFK_Pointer))
    return QualType();
 
  assert(!T->isObjCObjectType() && "Should build ObjCObjectPointerType");
 
  // In ARC, it is forbidden to build pointers to unqualified pointers.
  if (getLangOpts().ObjCAutoRefCount)
    T = inferARCLifetimeForPointee(*this, T, Loc, /*reference*/ false);
 
  if (getLangOpts().OpenCL)
    T = deduceOpenCLPointeeAddrSpace(*this, T);
 
  // In WebAssembly, pointers to reference types are illegal.
  if (getASTContext().getTargetInfo().getTriple().isWasm() &&
      T->isWebAssemblyReferenceType()) {
    Diag(Loc, diag::err_wasm_reference_pr) << 0;
    return QualType();
  }
 
  // Build the pointer type.
  return Context.getPointerType(T);
}
 
/// Build a reference type.
///
/// \param T The type to which we'll be building a reference.
///
/// \param Loc The location of the entity whose type involves this
/// reference type or, if there is no such entity, the location of the
/// type that will have reference type.
///
/// \param Entity The name of the entity that involves the reference
/// type, if known.
///
/// \returns A suitable reference type, if there are no
/// errors. Otherwise, returns a NULL type.
QualType Sema::BuildReferenceType(QualType T, bool SpelledAsLValue,
                                  SourceLocation Loc,
                                  DeclarationName Entity) {
  assert(Context.getCanonicalType(T) != Context.OverloadTy &&
         "Unresolved overloaded function type");
 
  // C++0x [dcl.ref]p6:
  //   If a typedef (7.1.3), a type template-parameter (14.3.1), or a
  //   decltype-specifier (7.1.6.2) denotes a type TR that is a reference to a
  //   type T, an attempt to create the type "lvalue reference to cv TR" creates
  //   the type "lvalue reference to T", while an attempt to create the type
  //   "rvalue reference to cv TR" creates the type TR.
  bool LValueRef = SpelledAsLValue || T->getAs<LValueReferenceType>();
 
  // C++ [dcl.ref]p4: There shall be no references to references.
  //
  // According to C++ DR 106, references to references are only
  // diagnosed when they are written directly (e.g., "int & &"),
  // but not when they happen via a typedef:
  //
  //   typedef int& intref;
  //   typedef intref& intref2;
  //
  // Parser::ParseDeclaratorInternal diagnoses the case where
  // references are written directly; here, we handle the
  // collapsing of references-to-references as described in C++0x.
  // DR 106 and 540 introduce reference-collapsing into C++98/03.
 
  // C++ [dcl.ref]p1:
  //   A declarator that specifies the type "reference to cv void"
  //   is ill-formed.
  if (T->isVoidType()) {
    Diag(Loc, diag::err_reference_to_void);
    return QualType();
  }
 
  if (getLangOpts().HLSL && Loc.isValid()) {
    Diag(Loc, diag::err_hlsl_pointers_unsupported) << 1;
    return QualType();
  }
 
  if (checkQualifiedFunction(*this, T, Loc, QFK_Reference))
    return QualType();
 
  if (T->isFunctionType() && getLangOpts().OpenCL &&
      !getOpenCLOptions().isAvailableOption("__cl_clang_function_pointers",
                                            getLangOpts())) {
    Diag(Loc, diag::err_opencl_function_pointer) << /*reference*/ 1;
    return QualType();
  }
 
  // In ARC, it is forbidden to build references to unqualified pointers.
  if (getLangOpts().ObjCAutoRefCount)
    T = inferARCLifetimeForPointee(*this, T, Loc, /*reference*/ true);
 
  if (getLangOpts().OpenCL)
    T = deduceOpenCLPointeeAddrSpace(*this, T);
 
  // In WebAssembly, references to reference types are illegal.
  if (getASTContext().getTargetInfo().getTriple().isWasm() &&
      T->isWebAssemblyReferenceType()) {
    Diag(Loc, diag::err_wasm_reference_pr) << 1;
    return QualType();
  }
 
  // Handle restrict on references.
  if (LValueRef)
    return Context.getLValueReferenceType(T, SpelledAsLValue);
  return Context.getRValueReferenceType(T);
}
 
/// Build a Read-only Pipe type.
///
/// \param T The type to which we'll be building a Pipe.
///
/// \param Loc We do not use it for now.
///
/// \returns A suitable pipe type, if there are no errors. Otherwise, returns a
/// NULL type.
QualType Sema::BuildReadPipeType(QualType T, SourceLocation Loc) {
  return Context.getReadPipeType(T);
}
 
/// Build a Write-only Pipe type.
///
/// \param T The type to which we'll be building a Pipe.
///
/// \param Loc We do not use it for now.
///
/// \returns A suitable pipe type, if there are no errors. Otherwise, returns a
/// NULL type.
QualType Sema::BuildWritePipeType(QualType T, SourceLocation Loc) {
  return Context.getWritePipeType(T);
}
 
/// Build a bit-precise integer type.
///
/// \param IsUnsigned Boolean representing the signedness of the type.
///
/// \param BitWidth Size of this int type in bits, or an expression representing
/// that.
///
/// \param Loc Location of the keyword.
QualType Sema::BuildBitIntType(bool IsUnsigned, Expr *BitWidth,
                               SourceLocation Loc) {
  if (BitWidth->isInstantiationDependent())
    return Context.getDependentBitIntType(IsUnsigned, BitWidth);
 
  llvm::APSInt Bits(32);
  ExprResult ICE =
      VerifyIntegerConstantExpression(BitWidth, &Bits, /*FIXME*/ AllowFold);
 
  if (ICE.isInvalid())
    return QualType();
 
  size_t NumBits = Bits.getZExtValue();
  if (!IsUnsigned && NumBits < 2) {
    Diag(Loc, diag::err_bit_int_bad_size) << 0;
    return QualType();
  }
 
  if (IsUnsigned && NumBits < 1) {
    Diag(Loc, diag::err_bit_int_bad_size) << 1;
    return QualType();
  }
 
  const TargetInfo &TI = getASTContext().getTargetInfo();
  if (NumBits > TI.getMaxBitIntWidth()) {
    Diag(Loc, diag::err_bit_int_max_size)
        << IsUnsigned << static_cast<uint64_t>(TI.getMaxBitIntWidth());
    return QualType();
  }
 
  return Context.getBitIntType(IsUnsigned, NumBits);
}
 
/// Check whether the specified array bound can be evaluated using the relevant
/// language rules. If so, returns the possibly-converted expression and sets
/// SizeVal to the size. If not, but the expression might be a VLA bound,
/// returns ExprResult(). Otherwise, produces a diagnostic and returns
/// ExprError().
static ExprResult checkArraySize(Sema &S, Expr *&ArraySize,
                                 llvm::APSInt &SizeVal, unsigned VLADiag,
                                 bool VLAIsError) {
  if (S.getLangOpts().CPlusPlus14 &&
      (VLAIsError ||
       !ArraySize->getType()->isIntegralOrUnscopedEnumerationType())) {
    // C++14 [dcl.array]p1:
    //   The constant-expression shall be a converted constant expression of
    //   type std::size_t.
    //
    // Don't apply this rule if we might be forming a VLA: in that case, we
    // allow non-constant expressions and constant-folding. We only need to use
    // the converted constant expression rules (to properly convert the source)
    // when the source expression is of class type.
    return S.CheckConvertedConstantExpression(
        ArraySize, S.Context.getSizeType(), SizeVal, Sema::CCEK_ArrayBound);
  }
 
  // If the size is an ICE, it certainly isn't a VLA. If we're in a GNU mode
  // (like gnu99, but not c99) accept any evaluatable value as an extension.
  class VLADiagnoser : public Sema::VerifyICEDiagnoser {
  public:
    unsigned VLADiag;
    bool VLAIsError;
    bool IsVLA = false;
 
    VLADiagnoser(unsigned VLADiag, bool VLAIsError)
        : VLADiag(VLADiag), VLAIsError(VLAIsError) {}
 
    Sema::SemaDiagnosticBuilder diagnoseNotICEType(Sema &S, SourceLocation Loc,
                                                   QualType T) override {
      return S.Diag(Loc, diag::err_array_size_non_int) << T;
    }
 
    Sema::SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
                                               SourceLocation Loc) override {
      IsVLA = !VLAIsError;
      return S.Diag(Loc, VLADiag);
    }
 
    Sema::SemaDiagnosticBuilder diagnoseFold(Sema &S,
                                             SourceLocation Loc) override {
      return S.Diag(Loc, diag::ext_vla_folded_to_constant);
    }
  } Diagnoser(VLADiag, VLAIsError);
 
  ExprResult R =
      S.VerifyIntegerConstantExpression(ArraySize, &SizeVal, Diagnoser);
  if (Diagnoser.IsVLA)
    return ExprResult();
  return R;
}
 
bool Sema::checkArrayElementAlignment(QualType EltTy, SourceLocation Loc) {
  EltTy = Context.getBaseElementType(EltTy);
  if (EltTy->isIncompleteType() || EltTy->isDependentType() ||
      EltTy->isUndeducedType())
    return true;
 
  CharUnits Size = Context.getTypeSizeInChars(EltTy);
  CharUnits Alignment = Context.getTypeAlignInChars(EltTy);
 
  if (Size.isMultipleOf(Alignment))
    return true;
 
  Diag(Loc, diag::err_array_element_alignment)
      << EltTy << Size.getQuantity() << Alignment.getQuantity();
  return false;
}
 
/// Build an array type.
///
/// \param T The type of each element in the array.
///
/// \param ASM C99 array size modifier (e.g., '*', 'static').
///
/// \param ArraySize Expression describing the size of the array.
///
/// \param Brackets The range from the opening '[' to the closing ']'.
///
/// \param Entity The name of the entity that involves the array
/// type, if known.
///
/// \returns A suitable array type, if there are no errors. Otherwise,
/// returns a NULL type.
QualType Sema::BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
                              Expr *ArraySize, unsigned Quals,
                              SourceRange Brackets, DeclarationName Entity) {
 
  SourceLocation Loc = Brackets.getBegin();
  if (getLangOpts().CPlusPlus) {
    // C++ [dcl.array]p1:
    //   T is called the array element type; this type shall not be a reference
    //   type, the (possibly cv-qualified) type void, a function type or an
    //   abstract class type.
    //
    // C++ [dcl.array]p3:
    //   When several "array of" specifications are adjacent, [...] only the
    //   first of the constant expressions that specify the bounds of the arrays
    //   may be omitted.
    //
    // Note: function types are handled in the common path with C.
    if (T->isReferenceType()) {
      Diag(Loc, diag::err_illegal_decl_array_of_references)
      << getPrintableNameForEntity(Entity) << T;
      return QualType();
    }
 
    if (T->isVoidType() || T->isIncompleteArrayType()) {
      Diag(Loc, diag::err_array_incomplete_or_sizeless_type) << 0 << T;
      return QualType();
    }
 
    if (RequireNonAbstractType(Brackets.getBegin(), T,
                               diag::err_array_of_abstract_type))
      return QualType();
 
    // Mentioning a member pointer type for an array type causes us to lock in
    // an inheritance model, even if it's inside an unused typedef.
    if (Context.getTargetInfo().getCXXABI().isMicrosoft())
      if (const MemberPointerType *MPTy = T->getAs<MemberPointerType>())
        if (!MPTy->getClass()->isDependentType())
          (void)isCompleteType(Loc, T);
 
  } else {
    // C99 6.7.5.2p1: If the element type is an incomplete or function type,
    // reject it (e.g. void ary[7], struct foo ary[7], void ary[7]())
    if (RequireCompleteSizedType(Loc, T,
                                 diag::err_array_incomplete_or_sizeless_type))
      return QualType();
  }
 
  if (T->isSizelessType()) {
    Diag(Loc, diag::err_array_incomplete_or_sizeless_type) << 1 << T;
    return QualType();
  }
 
  if (T->isFunctionType()) {
    Diag(Loc, diag::err_illegal_decl_array_of_functions)
      << getPrintableNameForEntity(Entity) << T;
    return QualType();
  }
 
  if (const RecordType *EltTy = T->getAs<RecordType>()) {
    // If the element type is a struct or union that contains a variadic
    // array, accept it as a GNU extension: C99 6.7.2.1p2.
    if (EltTy->getDecl()->hasFlexibleArrayMember())
      Diag(Loc, diag::ext_flexible_array_in_array) << T;
  } else if (T->isObjCObjectType()) {
    Diag(Loc, diag::err_objc_array_of_interfaces) << T;
    return QualType();
  }
 
  if (!checkArrayElementAlignment(T, Loc))
    return QualType();
 
  // Do placeholder conversions on the array size expression.
  if (ArraySize && ArraySize->hasPlaceholderType()) {
    ExprResult Result = CheckPlaceholderExpr(ArraySize);
    if (Result.isInvalid()) return QualType();
    ArraySize = Result.get();
  }
 
  // Do lvalue-to-rvalue conversions on the array size expression.
  if (ArraySize && !ArraySize->isPRValue()) {
    ExprResult Result = DefaultLvalueConversion(ArraySize);
    if (Result.isInvalid())
      return QualType();
 
    ArraySize = Result.get();
  }
 
  // C99 6.7.5.2p1: The size expression shall have integer type.
  // C++11 allows contextual conversions to such types.
  if (!getLangOpts().CPlusPlus11 &&
      ArraySize && !ArraySize->isTypeDependent() &&
      !ArraySize->getType()->isIntegralOrUnscopedEnumerationType()) {
    Diag(ArraySize->getBeginLoc(), diag::err_array_size_non_int)
        << ArraySize->getType() << ArraySize->getSourceRange();
    return QualType();
  }
 
  // VLAs always produce at least a -Wvla diagnostic, sometimes an error.
  unsigned VLADiag;
  bool VLAIsError;
  if (getLangOpts().OpenCL) {
    // OpenCL v1.2 s6.9.d: variable length arrays are not supported.
    VLADiag = diag::err_opencl_vla;
    VLAIsError = true;
  } else if (getLangOpts().C99) {
    VLADiag = diag::warn_vla_used;
    VLAIsError = false;
  } else if (isSFINAEContext()) {
    VLADiag = diag::err_vla_in_sfinae;
    VLAIsError = true;
  } else if (getLangOpts().OpenMP && isInOpenMPTaskUntiedContext()) {
    VLADiag = diag::err_openmp_vla_in_task_untied;
    VLAIsError = true;
  } else {
    VLADiag = diag::ext_vla;
    VLAIsError = false;
  }
 
  llvm::APSInt ConstVal(Context.getTypeSize(Context.getSizeType()));
  if (!ArraySize) {
    if (ASM == ArrayType::Star) {
      Diag(Loc, VLADiag);
      if (VLAIsError)
        return QualType();
 
      T = Context.getVariableArrayType(T, nullptr, ASM, Quals, Brackets);
    } else {
      T = Context.getIncompleteArrayType(T, ASM, Quals);
    }
  } else if (ArraySize->isTypeDependent() || ArraySize->isValueDependent()) {
    T = Context.getDependentSizedArrayType(T, ArraySize, ASM, Quals, Brackets);
  } else {
    ExprResult R =
        checkArraySize(*this, ArraySize, ConstVal, VLADiag, VLAIsError);
    if (R.isInvalid())
      return QualType();
 
    if (!R.isUsable()) {
      // C99: an array with a non-ICE size is a VLA. We accept any expression
      // that we can fold to a non-zero positive value as a non-VLA as an
      // extension.
      T = Context.getVariableArrayType(T, ArraySize, ASM, Quals, Brackets);
    } else if (!T->isDependentType() && !T->isIncompleteType() &&
               !T->isConstantSizeType()) {
      // C99: an array with an element type that has a non-constant-size is a
      // VLA.
      // FIXME: Add a note to explain why this isn't a VLA.
      Diag(Loc, VLADiag);
      if (VLAIsError)
        return QualType();
      T = Context.getVariableArrayType(T, ArraySize, ASM, Quals, Brackets);
    } else {
      // C99 6.7.5.2p1: If the expression is a constant expression, it shall
      // have a value greater than zero.
      // In C++, this follows from narrowing conversions being disallowed.
      if (ConstVal.isSigned() && ConstVal.isNegative()) {
        if (Entity)
          Diag(ArraySize->getBeginLoc(), diag::err_decl_negative_array_size)
              << getPrintableNameForEntity(Entity)
              << ArraySize->getSourceRange();
        else
          Diag(ArraySize->getBeginLoc(),
               diag::err_typecheck_negative_array_size)
              << ArraySize->getSourceRange();
        return QualType();
      }
      if (ConstVal == 0) {
        // GCC accepts zero sized static arrays. We allow them when
        // we're not in a SFINAE context.
        Diag(ArraySize->getBeginLoc(),
             isSFINAEContext() ? diag::err_typecheck_zero_array_size
                               : diag::ext_typecheck_zero_array_size)
            << 0 << ArraySize->getSourceRange();
      }
 
      // Is the array too large?
      unsigned ActiveSizeBits =
          (!T->isDependentType() && !T->isVariablyModifiedType() &&
           !T->isIncompleteType() && !T->isUndeducedType())
              ? ConstantArrayType::getNumAddressingBits(Context, T, ConstVal)
              : ConstVal.getActiveBits();
      if (ActiveSizeBits > ConstantArrayType::getMaxSizeBits(Context)) {
        Diag(ArraySize->getBeginLoc(), diag::err_array_too_large)
            << toString(ConstVal, 10) << ArraySize->getSourceRange();
        return QualType();
      }
 
      T = Context.getConstantArrayType(T, ConstVal, ArraySize, ASM, Quals);
    }
  }
 
  if (T->isVariableArrayType() && !Context.getTargetInfo().isVLASupported()) {
    // CUDA device code and some other targets don't support VLAs.
    bool IsCUDADevice = (getLangOpts().CUDA && getLangOpts().CUDAIsDevice);
    targetDiag(Loc,
               IsCUDADevice ? diag::err_cuda_vla : diag::err_vla_unsupported)
        << (IsCUDADevice ? CurrentCUDATarget() : 0);
  }
 
  // If this is not C99, diagnose array size modifiers on non-VLAs.
  if (!getLangOpts().C99 && !T->isVariableArrayType() &&
      (ASM != ArrayType::Normal || Quals != 0)) {
    Diag(Loc, getLangOpts().CPlusPlus ? diag::err_c99_array_usage_cxx
                                      : diag::ext_c99_array_usage)
        << ASM;
  }
 
  // OpenCL v2.0 s6.12.5 - Arrays of blocks are not supported.
  // OpenCL v2.0 s6.16.13.1 - Arrays of pipe type are not supported.
  // OpenCL v2.0 s6.9.b - Arrays of image/sampler type are not supported.
  if (getLangOpts().OpenCL) {
    const QualType ArrType = Context.getBaseElementType(T);
    if (ArrType->isBlockPointerType() || ArrType->isPipeType() ||
        ArrType->isSamplerT() || ArrType->isImageType()) {
      Diag(Loc, diag::err_opencl_invalid_type_array) << ArrType;
      return QualType();
    }
  }
 
  return T;
}
 
QualType Sema::BuildVectorType(QualType CurType, Expr *SizeExpr,
                               SourceLocation AttrLoc) {
  // The base type must be integer (not Boolean or enumeration) or float, and
  // can't already be a vector.
  if ((!CurType->isDependentType() &&
       (!CurType->isBuiltinType() || CurType->isBooleanType() ||
        (!CurType->isIntegerType() && !CurType->isRealFloatingType())) &&
       !CurType->isBitIntType()) ||
      CurType->isArrayType()) {
    Diag(AttrLoc, diag::err_attribute_invalid_vector_type) << CurType;
    return QualType();
  }
  // Only support _BitInt elements with byte-sized power of 2 NumBits.
  if (CurType->isBitIntType()) {
    unsigned NumBits = CurType->getAs<BitIntType>()->getNumBits();
    if (!llvm::isPowerOf2_32(NumBits) || NumBits < 8) {
      Diag(AttrLoc, diag::err_attribute_invalid_bitint_vector_type)
          << (NumBits < 8);
      return QualType();
    }
  }
 
  if (SizeExpr->isTypeDependent() || SizeExpr->isValueDependent())
    return Context.getDependentVectorType(CurType, SizeExpr, AttrLoc,
                                               VectorType::GenericVector);
 
  std::optional<llvm::APSInt> VecSize =
      SizeExpr->getIntegerConstantExpr(Context);
  if (!VecSize) {
    Diag(AttrLoc, diag::err_attribute_argument_type)
        << "vector_size" << AANT_ArgumentIntegerConstant
        << SizeExpr->getSourceRange();
    return QualType();
  }
 
  if (CurType->isDependentType())
    return Context.getDependentVectorType(CurType, SizeExpr, AttrLoc,
                                               VectorType::GenericVector);
 
  // vecSize is specified in bytes - convert to bits.
  if (!VecSize->isIntN(61)) {
    // Bit size will overflow uint64.
    Diag(AttrLoc, diag::err_attribute_size_too_large)
        << SizeExpr->getSourceRange() << "vector";
    return QualType();
  }
  uint64_t VectorSizeBits = VecSize->getZExtValue() * 8;
  unsigned TypeSize = static_cast<unsigned>(Context.getTypeSize(CurType));
 
  if (VectorSizeBits == 0) {
    Diag(AttrLoc, diag::err_attribute_zero_size)
        << SizeExpr->getSourceRange() << "vector";
    return QualType();
  }
 
  if (!TypeSize || VectorSizeBits % TypeSize) {
    Diag(AttrLoc, diag::err_attribute_invalid_size)
        << SizeExpr->getSourceRange();
    return QualType();
  }
 
  if (VectorSizeBits / TypeSize > std::numeric_limits<uint32_t>::max()) {
    Diag(AttrLoc, diag::err_attribute_size_too_large)
        << SizeExpr->getSourceRange() << "vector";
    return QualType();
  }
 
  return Context.getVectorType(CurType, VectorSizeBits / TypeSize,
                               VectorType::GenericVector);
}
 
/// Build an ext-vector type.
///
/// Run the required checks for the extended vector type.
QualType Sema::BuildExtVectorType(QualType T, Expr *ArraySize,
                                  SourceLocation AttrLoc) {
  // Unlike gcc's vector_size attribute, we do not allow vectors to be defined
  // in conjunction with complex types (pointers, arrays, functions, etc.).
  //
  // Additionally, OpenCL prohibits vectors of booleans (they're considered a
  // reserved data type under OpenCL v2.0 s6.1.4), we don't support selects
  // on bitvectors, and we have no well-defined ABI for bitvectors, so vectors
  // of bool aren't allowed.
  //
  // We explictly allow bool elements in ext_vector_type for C/C++.
  bool IsNoBoolVecLang = getLangOpts().OpenCL || getLangOpts().OpenCLCPlusPlus;
  if ((!T->isDependentType() && !T->isIntegerType() &&
       !T->isRealFloatingType()) ||
      (IsNoBoolVecLang && T->isBooleanType())) {
    Diag(AttrLoc, diag::err_attribute_invalid_vector_type) << T;
    return QualType();
  }
 
  // Only support _BitInt elements with byte-sized power of 2 NumBits.
  if (T->isBitIntType()) {
    unsigned NumBits = T->getAs<BitIntType>()->getNumBits();
    if (!llvm::isPowerOf2_32(NumBits) || NumBits < 8) {
      Diag(AttrLoc, diag::err_attribute_invalid_bitint_vector_type)
          << (NumBits < 8);
      return QualType();
    }
  }
 
  if (!ArraySize->isTypeDependent() && !ArraySize->isValueDependent()) {
    std::optional<llvm::APSInt> vecSize =
        ArraySize->getIntegerConstantExpr(Context);
    if (!vecSize) {
      Diag(AttrLoc, diag::err_attribute_argument_type)
        << "ext_vector_type" << AANT_ArgumentIntegerConstant
        << ArraySize->getSourceRange();
      return QualType();
    }
 
    if (!vecSize->isIntN(32)) {
      Diag(AttrLoc, diag::err_attribute_size_too_large)
          << ArraySize->getSourceRange() << "vector";
      return QualType();
    }
    // Unlike gcc's vector_size attribute, the size is specified as the
    // number of elements, not the number of bytes.
    unsigned vectorSize = static_cast<unsigned>(vecSize->getZExtValue());
 
    if (vectorSize == 0) {
      Diag(AttrLoc, diag::err_attribute_zero_size)
          << ArraySize->getSourceRange() << "vector";
      return QualType();
    }
 
    return Context.getExtVectorType(T, vectorSize);
  }
 
  return Context.getDependentSizedExtVectorType(T, ArraySize, AttrLoc);
}
 
QualType Sema::BuildMatrixType(QualType ElementTy, Expr *NumRows, Expr *NumCols,
                               SourceLocation AttrLoc) {
  assert(Context.getLangOpts().MatrixTypes &&
         "Should never build a matrix type when it is disabled");
 
  // Check element type, if it is not dependent.
  if (!ElementTy->isDependentType() &&
      !MatrixType::isValidElementType(ElementTy)) {
    Diag(AttrLoc, diag::err_attribute_invalid_matrix_type) << ElementTy;
    return QualType();
  }
 
  if (NumRows->isTypeDependent() || NumCols->isTypeDependent() ||
      NumRows->isValueDependent() || NumCols->isValueDependent())
    return Context.getDependentSizedMatrixType(ElementTy, NumRows, NumCols,
                                               AttrLoc);
 
  std::optional<llvm::APSInt> ValueRows =
      NumRows->getIntegerConstantExpr(Context);
  std::optional<llvm::APSInt> ValueColumns =
      NumCols->getIntegerConstantExpr(Context);
 
  auto const RowRange = NumRows->getSourceRange();
  auto const ColRange = NumCols->getSourceRange();
 
  // Both are row and column expressions are invalid.
  if (!ValueRows && !ValueColumns) {
    Diag(AttrLoc, diag::err_attribute_argument_type)
        << "matrix_type" << AANT_ArgumentIntegerConstant << RowRange
        << ColRange;
    return QualType();
  }
 
  // Only the row expression is invalid.
  if (!ValueRows) {
    Diag(AttrLoc, diag::err_attribute_argument_type)
        << "matrix_type" << AANT_ArgumentIntegerConstant << RowRange;
    return QualType();
  }
 
  // Only the column expression is invalid.
  if (!ValueColumns) {
    Diag(AttrLoc, diag::err_attribute_argument_type)
        << "matrix_type" << AANT_ArgumentIntegerConstant << ColRange;
    return QualType();
  }
 
  // Check the matrix dimensions.
  unsigned MatrixRows = static_cast<unsigned>(ValueRows->getZExtValue());
  unsigned MatrixColumns = static_cast<unsigned>(ValueColumns->getZExtValue());
  if (MatrixRows == 0 && MatrixColumns == 0) {
    Diag(AttrLoc, diag::err_attribute_zero_size)
        << "matrix" << RowRange << ColRange;
    return QualType();
  }
  if (MatrixRows == 0) {
    Diag(AttrLoc, diag::err_attribute_zero_size) << "matrix" << RowRange;
    return QualType();
  }
  if (MatrixColumns == 0) {
    Diag(AttrLoc, diag::err_attribute_zero_size) << "matrix" << ColRange;
    return QualType();
  }
  if (!ConstantMatrixType::isDimensionValid(MatrixRows)) {
    Diag(AttrLoc, diag::err_attribute_size_too_large)
        << RowRange << "matrix row";
    return QualType();
  }
  if (!ConstantMatrixType::isDimensionValid(MatrixColumns)) {
    Diag(AttrLoc, diag::err_attribute_size_too_large)
        << ColRange << "matrix column";
    return QualType();
  }
  return Context.getConstantMatrixType(ElementTy, MatrixRows, MatrixColumns);
}
 
bool Sema::CheckFunctionReturnType(QualType T, SourceLocation Loc) {
  if (T->isArrayType() || T->isFunctionType()) {
    Diag(Loc, diag::err_func_returning_array_function)
      << T->isFunctionType() << T;
    return true;
  }
 
  // Functions cannot return half FP.
  if (T->isHalfType() && !getLangOpts().NativeHalfArgsAndReturns &&
      !Context.getTargetInfo().allowHalfArgsAndReturns()) {
    Diag(Loc, diag::err_parameters_retval_cannot_have_fp16_type) << 1 <<
      FixItHint::CreateInsertion(Loc, "*");
    return true;
  }
 
  // Methods cannot return interface types. All ObjC objects are
  // passed by reference.
  if (T->isObjCObjectType()) {
    Diag(Loc, diag::err_object_cannot_be_passed_returned_by_value)
        << 0 << T << FixItHint::CreateInsertion(Loc, "*");
    return true;
  }
 
  if (T.hasNonTrivialToPrimitiveDestructCUnion() ||
      T.hasNonTrivialToPrimitiveCopyCUnion())
    checkNonTrivialCUnion(T, Loc, NTCUC_FunctionReturn,
                          NTCUK_Destruct|NTCUK_Copy);
 
  // C++2a [dcl.fct]p12:
  //   A volatile-qualified return type is deprecated
  if (T.isVolatileQualified() && getLangOpts().CPlusPlus20)
    Diag(Loc, diag::warn_deprecated_volatile_return) << T;
 
  if (T.getAddressSpace() != LangAS::Default && getLangOpts().HLSL)
    return true;
  return false;
}
 
/// Check the extended parameter information.  Most of the necessary
/// checking should occur when applying the parameter attribute; the
/// only other checks required are positional restrictions.
static void checkExtParameterInfos(Sema &S, ArrayRef<QualType> paramTypes,
                    const FunctionProtoType::ExtProtoInfo &EPI,
                    llvm::function_ref<SourceLocation(unsigned)> getParamLoc) {
  assert(EPI.ExtParameterInfos && "shouldn't get here without param infos");
 
  bool emittedError = false;
  auto actualCC = EPI.ExtInfo.getCC();
  enum class RequiredCC { OnlySwift, SwiftOrSwiftAsync };
  auto checkCompatible = [&](unsigned paramIndex, RequiredCC required) {
    bool isCompatible =
        (required == RequiredCC::OnlySwift)
            ? (actualCC == CC_Swift)
            : (actualCC == CC_Swift || actualCC == CC_SwiftAsync);
    if (isCompatible || emittedError)
      return;
    S.Diag(getParamLoc(paramIndex), diag::err_swift_param_attr_not_swiftcall)
        << getParameterABISpelling(EPI.ExtParameterInfos[paramIndex].getABI())
        << (required == RequiredCC::OnlySwift);
    emittedError = true;
  };
  for (size_t paramIndex = 0, numParams = paramTypes.size();
          paramIndex != numParams; ++paramIndex) {
    switch (EPI.ExtParameterInfos[paramIndex].getABI()) {
    // Nothing interesting to check for orindary-ABI parameters.
    case ParameterABI::Ordinary:
      continue;
 
    // swift_indirect_result parameters must be a prefix of the function
    // arguments.
    case ParameterABI::SwiftIndirectResult:
      checkCompatible(paramIndex, RequiredCC::SwiftOrSwiftAsync);
      if (paramIndex != 0 &&
          EPI.ExtParameterInfos[paramIndex - 1].getABI()
            != ParameterABI::SwiftIndirectResult) {
        S.Diag(getParamLoc(paramIndex),
               diag::err_swift_indirect_result_not_first);
      }
      continue;
 
    case ParameterABI::SwiftContext:
      checkCompatible(paramIndex, RequiredCC::SwiftOrSwiftAsync);
      continue;
 
    // SwiftAsyncContext is not limited to swiftasynccall functions.
    case ParameterABI::SwiftAsyncContext:
      continue;
 
    // swift_error parameters must be preceded by a swift_context parameter.
    case ParameterABI::SwiftErrorResult:
      checkCompatible(paramIndex, RequiredCC::OnlySwift);
      if (paramIndex == 0 ||
          EPI.ExtParameterInfos[paramIndex - 1].getABI() !=
              ParameterABI::SwiftContext) {
        S.Diag(getParamLoc(paramIndex),
               diag::err_swift_error_result_not_after_swift_context);
      }
      continue;
    }
    llvm_unreachable("bad ABI kind");
  }
}
 
QualType Sema::BuildFunctionType(QualType T,
                                 MutableArrayRef<QualType> ParamTypes,
                                 SourceLocation Loc, DeclarationName Entity,
                                 const FunctionProtoType::ExtProtoInfo &EPI) {
  bool Invalid = false;
 
  Invalid |= CheckFunctionReturnType(T, Loc);
 
  for (unsigned Idx = 0, Cnt = ParamTypes.size(); Idx < Cnt; ++Idx) {
    // FIXME: Loc is too inprecise here, should use proper locations for args.
    QualType ParamType = Context.getAdjustedParameterType(ParamTypes[Idx]);
    if (ParamType->isVoidType()) {
      Diag(Loc, diag::err_param_with_void_type);
      Invalid = true;
    } else if (ParamType->isHalfType() && !getLangOpts().NativeHalfArgsAndReturns &&
               !Context.getTargetInfo().allowHalfArgsAndReturns()) {
      // Disallow half FP arguments.
      Diag(Loc, diag::err_parameters_retval_cannot_have_fp16_type) << 0 <<
        FixItHint::CreateInsertion(Loc, "*");
      Invalid = true;
    }
 
    // C++2a [dcl.fct]p4:
    //   A parameter with volatile-qualified type is deprecated
    if (ParamType.isVolatileQualified() && getLangOpts().CPlusPlus20)
      Diag(Loc, diag::warn_deprecated_volatile_param) << ParamType;
 
    ParamTypes[Idx] = ParamType;
  }
 
  if (EPI.ExtParameterInfos) {
    checkExtParameterInfos(*this, ParamTypes, EPI,
                           [=](unsigned i) { return Loc; });
  }
 
  if (EPI.ExtInfo.getProducesResult()) {
    // This is just a warning, so we can't fail to build if we see it.
    checkNSReturnsRetainedReturnType(Loc, T);
  }
 
  if (Invalid)
    return QualType();
 
  return Context.getFunctionType(T, ParamTypes, EPI);
}
 
/// Build a member pointer type \c T Class::*.
///
/// \param T the type to which the member pointer refers.
/// \param Class the class type into which the member pointer points.
/// \param Loc the location where this type begins
/// \param Entity the name of the entity that will have this member pointer type
///
/// \returns a member pointer type, if successful, or a NULL type if there was
/// an error.
QualType Sema::BuildMemberPointerType(QualType T, QualType Class,
                                      SourceLocation Loc,
                                      DeclarationName Entity) {
  // Verify that we're not building a pointer to pointer to function with
  // exception specification.
  if (CheckDistantExceptionSpec(T)) {
    Diag(Loc, diag::err_distant_exception_spec);
    return QualType();
  }
 
  // C++ 8.3.3p3: A pointer to member shall not point to ... a member
  //   with reference type, or "cv void."
  if (T->isReferenceType()) {
    Diag(Loc, diag::err_illegal_decl_mempointer_to_reference)
      << getPrintableNameForEntity(Entity) << T;
    return QualType();
  }
 
  if (T->isVoidType()) {
    Diag(Loc, diag::err_illegal_decl_mempointer_to_void)
      << getPrintableNameForEntity(Entity);
    return QualType();
  }
 
  if (!Class->isDependentType() && !Class->isRecordType()) {
    Diag(Loc, diag::err_mempointer_in_nonclass_type) << Class;
    return QualType();
  }
 
  if (T->isFunctionType() && getLangOpts().OpenCL &&
      !getOpenCLOptions().isAvailableOption("__cl_clang_function_pointers",
                                            getLangOpts())) {
    Diag(Loc, diag::err_opencl_function_pointer) << /*pointer*/ 0;
    return QualType();
  }
 
  if (getLangOpts().HLSL && Loc.isValid()) {
    Diag(Loc, diag::err_hlsl_pointers_unsupported) << 0;
    return QualType();
  }
 
  // Adjust the default free function calling convention to the default method
  // calling convention.
  bool IsCtorOrDtor =
      (Entity.getNameKind() == DeclarationName::CXXConstructorName) ||
      (Entity.getNameKind() == DeclarationName::CXXDestructorName);
  if (T->isFunctionType())
    adjustMemberFunctionCC(T, /*IsStatic=*/false, IsCtorOrDtor, Loc);
 
  return Context.getMemberPointerType(T, Class.getTypePtr());
}
 
/// Build a block pointer type.
///
/// \param T The type to which we'll be building a block pointer.
///
/// \param Loc The source location, used for diagnostics.
///
/// \param Entity The name of the entity that involves the block pointer
/// type, if known.
///
/// \returns A suitable block pointer type, if there are no
/// errors. Otherwise, returns a NULL type.
QualType Sema::BuildBlockPointerType(QualType T,
                                     SourceLocation Loc,
                                     DeclarationName Entity) {
  if (!T->isFunctionType()) {
    Diag(Loc, diag::err_nonfunction_block_type);
    return QualType();
  }
 
  if (checkQualifiedFunction(*this, T, Loc, QFK_BlockPointer))
    return QualType();
 
  if (getLangOpts().OpenCL)
    T = deduceOpenCLPointeeAddrSpace(*this, T);
 
  return Context.getBlockPointerType(T);
}
 
QualType Sema::GetTypeFromParser(ParsedType Ty, TypeSourceInfo **TInfo) {
  QualType QT = Ty.get();
  if (QT.isNull()) {
    if (TInfo) *TInfo = nullptr;
    return QualType();
  }
 
  TypeSourceInfo *DI = nullptr;
  if (const LocInfoType *LIT = dyn_cast<LocInfoType>(QT)) {
    QT = LIT->getType();
    DI = LIT->getTypeSourceInfo();
  }
 
  if (TInfo) *TInfo = DI;
  return QT;
}
 
static void transferARCOwnershipToDeclaratorChunk(TypeProcessingState &state,
                                            Qualifiers::ObjCLifetime ownership,
                                            unsigned chunkIndex);
 
/// Given that this is the declaration of a parameter under ARC,
/// attempt to infer attributes and such for pointer-to-whatever
/// types.
static void inferARCWriteback(TypeProcessingState &state,
                              QualType &declSpecType) {
  Sema &S = state.getSema();
  Declarator &declarator = state.getDeclarator();
 
  // TODO: should we care about decl qualifiers?
 
  // Check whether the declarator has the expected form.  We walk
  // from the inside out in order to make the block logic work.
  unsigned outermostPointerIndex = 0;
  bool isBlockPointer = false;
  unsigned numPointers = 0;
  for (unsigned i = 0, e = declarator.getNumTypeObjects(); i != e; ++i) {
    unsigned chunkIndex = i;
    DeclaratorChunk &chunk = declarator.getTypeObject(chunkIndex);
    switch (chunk.Kind) {
    case DeclaratorChunk::Paren:
      // Ignore parens.
      break;
 
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::Pointer:
      // Count the number of pointers.  Treat references
      // interchangeably as pointers; if they're mis-ordered, normal
      // type building will discover that.
      outermostPointerIndex = chunkIndex;
      numPointers++;
      break;
 
    case DeclaratorChunk::BlockPointer:
      // If we have a pointer to block pointer, that's an acceptable
      // indirect reference; anything else is not an application of
      // the rules.
      if (numPointers != 1) return;
      numPointers++;
      outermostPointerIndex = chunkIndex;
      isBlockPointer = true;
 
      // We don't care about pointer structure in return values here.
      goto done;
 
    case DeclaratorChunk::Array: // suppress if written (id[])?
    case DeclaratorChunk::Function:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Pipe:
      return;
    }
  }
 done:
 
  // If we have *one* pointer, then we want to throw the qualifier on
  // the declaration-specifiers, which means that it needs to be a
  // retainable object type.
  if (numPointers == 1) {
    // If it's not a retainable object type, the rule doesn't apply.
    if (!declSpecType->isObjCRetainableType()) return;
 
    // If it already has lifetime, don't do anything.
    if (declSpecType.getObjCLifetime()) return;
 
    // Otherwise, modify the type in-place.
    Qualifiers qs;
 
    if (declSpecType->isObjCARCImplicitlyUnretainedType())
      qs.addObjCLifetime(Qualifiers::OCL_ExplicitNone);
    else
      qs.addObjCLifetime(Qualifiers::OCL_Autoreleasing);
    declSpecType = S.Context.getQualifiedType(declSpecType, qs);
 
  // If we have *two* pointers, then we want to throw the qualifier on
  // the outermost pointer.
  } else if (numPointers == 2) {
    // If we don't have a block pointer, we need to check whether the
    // declaration-specifiers gave us something that will turn into a
    // retainable object pointer after we slap the first pointer on it.
    if (!isBlockPointer && !declSpecType->isObjCObjectType())
      return;
 
    // Look for an explicit lifetime attribute there.
    DeclaratorChunk &chunk = declarator.getTypeObject(outermostPointerIndex);
    if (chunk.Kind != DeclaratorChunk::Pointer &&
        chunk.Kind != DeclaratorChunk::BlockPointer)
      return;
    for (const ParsedAttr &AL : chunk.getAttrs())
      if (AL.getKind() == ParsedAttr::AT_ObjCOwnership)
        return;
 
    transferARCOwnershipToDeclaratorChunk(state, Qualifiers::OCL_Autoreleasing,
                                          outermostPointerIndex);
 
  // Any other number of pointers/references does not trigger the rule.
  } else return;
 
  // TODO: mark whether we did this inference?
}
 
void Sema::diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                                     SourceLocation FallbackLoc,
                                     SourceLocation ConstQualLoc,
                                     SourceLocation VolatileQualLoc,
                                     SourceLocation RestrictQualLoc,
                                     SourceLocation AtomicQualLoc,
                                     SourceLocation UnalignedQualLoc) {
  if (!Quals)
    return;
 
  struct Qual {
    const char *Name;
    unsigned Mask;
    SourceLocation Loc;
  } const QualKinds[5] = {
    { "const", DeclSpec::TQ_const, ConstQualLoc },
    { "volatile", DeclSpec::TQ_volatile, VolatileQualLoc },
    { "restrict", DeclSpec::TQ_restrict, RestrictQualLoc },
    { "__unaligned", DeclSpec::TQ_unaligned, UnalignedQualLoc },
    { "_Atomic", DeclSpec::TQ_atomic, AtomicQualLoc }
  };
 
  SmallString<32> QualStr;
  unsigned NumQuals = 0;
  SourceLocation Loc;
  FixItHint FixIts[5];
 
  // Build a string naming the redundant qualifiers.
  for (auto &E : QualKinds) {
    if (Quals & E.Mask) {
      if (!QualStr.empty()) QualStr += ' ';
      QualStr += E.Name;
 
      // If we have a location for the qualifier, offer a fixit.
      SourceLocation QualLoc = E.Loc;
      if (QualLoc.isValid()) {
        FixIts[NumQuals] = FixItHint::CreateRemoval(QualLoc);
        if (Loc.isInvalid() ||
            getSourceManager().isBeforeInTranslationUnit(QualLoc, Loc))
          Loc = QualLoc;
      }
 
      ++NumQuals;
    }
  }
 
  Diag(Loc.isInvalid() ? FallbackLoc : Loc, DiagID)
    << QualStr << NumQuals << FixIts[0] << FixIts[1] << FixIts[2] << FixIts[3];
}
 
// Diagnose pointless type qualifiers on the return type of a function.
static void diagnoseRedundantReturnTypeQualifiers(Sema &S, QualType RetTy,
                                                  Declarator &D,
                                                  unsigned FunctionChunkIndex) {
  const DeclaratorChunk::FunctionTypeInfo &FTI =
      D.getTypeObject(FunctionChunkIndex).Fun;
  if (FTI.hasTrailingReturnType()) {
    S.diagnoseIgnoredQualifiers(diag::warn_qual_return_type,
                                RetTy.getLocalCVRQualifiers(),
                                FTI.getTrailingReturnTypeLoc());
    return;
  }
 
  for (unsigned OuterChunkIndex = FunctionChunkIndex + 1,
                End = D.getNumTypeObjects();
       OuterChunkIndex != End; ++OuterChunkIndex) {
    DeclaratorChunk &OuterChunk = D.getTypeObject(OuterChunkIndex);
    switch (OuterChunk.Kind) {
    case DeclaratorChunk::Paren:
      continue;
 
    case DeclaratorChunk::Pointer: {
      DeclaratorChunk::PointerTypeInfo &PTI = OuterChunk.Ptr;
      S.diagnoseIgnoredQualifiers(
          diag::warn_qual_return_type,
          PTI.TypeQuals,
          SourceLocation(),
          PTI.ConstQualLoc,
          PTI.VolatileQualLoc,
          PTI.RestrictQualLoc,
          PTI.AtomicQualLoc,
          PTI.UnalignedQualLoc);
      return;
    }
 
    case DeclaratorChunk::Function:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::Array:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Pipe:
      // FIXME: We can't currently provide an accurate source location and a
      // fix-it hint for these.
      unsigned AtomicQual = RetTy->isAtomicType() ? DeclSpec::TQ_atomic : 0;
      S.diagnoseIgnoredQualifiers(diag::warn_qual_return_type,
                                  RetTy.getCVRQualifiers() | AtomicQual,
                                  D.getIdentifierLoc());
      return;
    }
 
    llvm_unreachable("unknown declarator chunk kind");
  }
 
  // If the qualifiers come from a conversion function type, don't diagnose
  // them -- they're not necessarily redundant, since such a conversion
  // operator can be explicitly called as "x.operator const int()".
  if (D.getName().getKind() == UnqualifiedIdKind::IK_ConversionFunctionId)
    return;
 
  // Just parens all the way out to the decl specifiers. Diagnose any qualifiers
  // which are present there.
  S.diagnoseIgnoredQualifiers(diag::warn_qual_return_type,
                              D.getDeclSpec().getTypeQualifiers(),
                              D.getIdentifierLoc(),
                              D.getDeclSpec().getConstSpecLoc(),
                              D.getDeclSpec().getVolatileSpecLoc(),
                              D.getDeclSpec().getRestrictSpecLoc(),
                              D.getDeclSpec().getAtomicSpecLoc(),
                              D.getDeclSpec().getUnalignedSpecLoc());
}
 
static std::pair<QualType, TypeSourceInfo *>
InventTemplateParameter(TypeProcessingState &state, QualType T,
                        TypeSourceInfo *TrailingTSI, AutoType *Auto,
                        InventedTemplateParameterInfo &Info) {
  Sema &S = state.getSema();
  Declarator &D = state.getDeclarator();
 
  const unsigned TemplateParameterDepth = Info.AutoTemplateParameterDepth;
  const unsigned AutoParameterPosition = Info.TemplateParams.size();
  const bool IsParameterPack = D.hasEllipsis();
 
  // If auto is mentioned in a lambda parameter or abbreviated function
  // template context, convert it to a template parameter type.
 
  // Create the TemplateTypeParmDecl here to retrieve the corresponding
  // template parameter type. Template parameters are temporarily added
  // to the TU until the associated TemplateDecl is created.
  TemplateTypeParmDecl *InventedTemplateParam =
      TemplateTypeParmDecl::Create(
          S.Context, S.Context.getTranslationUnitDecl(),
          /*KeyLoc=*/D.getDeclSpec().getTypeSpecTypeLoc(),
          /*NameLoc=*/D.getIdentifierLoc(),
          TemplateParameterDepth, AutoParameterPosition,
          S.InventAbbreviatedTemplateParameterTypeName(
              D.getIdentifier(), AutoParameterPosition), false,
          IsParameterPack, /*HasTypeConstraint=*/Auto->isConstrained());
  InventedTemplateParam->setImplicit();
  Info.TemplateParams.push_back(InventedTemplateParam);
 
  // Attach type constraints to the new parameter.
  if (Auto->isConstrained()) {
    if (TrailingTSI) {
      // The 'auto' appears in a trailing return type we've already built;
      // extract its type constraints to attach to the template parameter.
      AutoTypeLoc AutoLoc = TrailingTSI->getTypeLoc().getContainedAutoTypeLoc();
      TemplateArgumentListInfo TAL(AutoLoc.getLAngleLoc(), AutoLoc.getRAngleLoc());
      bool Invalid = false;
      for (unsigned Idx = 0; Idx < AutoLoc.getNumArgs(); ++Idx) {
        if (D.getEllipsisLoc().isInvalid() && !Invalid &&
            S.DiagnoseUnexpandedParameterPack(AutoLoc.getArgLoc(Idx),
                                              Sema::UPPC_TypeConstraint))
          Invalid = true;
        TAL.addArgument(AutoLoc.getArgLoc(Idx));
      }
 
      if (!Invalid) {
        S.AttachTypeConstraint(
            AutoLoc.getNestedNameSpecifierLoc(), AutoLoc.getConceptNameInfo(),
            AutoLoc.getNamedConcept(),
            AutoLoc.hasExplicitTemplateArgs() ? &TAL : nullptr,
            InventedTemplateParam, D.getEllipsisLoc());
      }
    } else {
      // The 'auto' appears in the decl-specifiers; we've not finished forming
      // TypeSourceInfo for it yet.
      TemplateIdAnnotation *TemplateId = D.getDeclSpec().getRepAsTemplateId();
      TemplateArgumentListInfo TemplateArgsInfo;
      bool Invalid = false;
      if (TemplateId->LAngleLoc.isValid()) {
        ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
                                           TemplateId->NumArgs);
        S.translateTemplateArguments(TemplateArgsPtr, TemplateArgsInfo);
 
        if (D.getEllipsisLoc().isInvalid()) {
          for (TemplateArgumentLoc Arg : TemplateArgsInfo.arguments()) {
            if (S.DiagnoseUnexpandedParameterPack(Arg,
                                                  Sema::UPPC_TypeConstraint)) {
              Invalid = true;
              break;
            }
          }
        }
      }
      if (!Invalid) {
        S.AttachTypeConstraint(
            D.getDeclSpec().getTypeSpecScope().getWithLocInContext(S.Context),
            DeclarationNameInfo(DeclarationName(TemplateId->Name),
                                TemplateId->TemplateNameLoc),
            cast<ConceptDecl>(TemplateId->Template.get().getAsTemplateDecl()),
            TemplateId->LAngleLoc.isValid() ? &TemplateArgsInfo : nullptr,
            InventedTemplateParam, D.getEllipsisLoc());
      }
    }
  }
 
  // Replace the 'auto' in the function parameter with this invented
  // template type parameter.
  // FIXME: Retain some type sugar to indicate that this was written
  //  as 'auto'?
  QualType Replacement(InventedTemplateParam->getTypeForDecl(), 0);
  QualType NewT = state.ReplaceAutoType(T, Replacement);
  TypeSourceInfo *NewTSI =
      TrailingTSI ? S.ReplaceAutoTypeSourceInfo(TrailingTSI, Replacement)
                  : nullptr;
  return {NewT, NewTSI};
}
 
static TypeSourceInfo *
GetTypeSourceInfoForDeclarator(TypeProcessingState &State,
                               QualType T, TypeSourceInfo *ReturnTypeInfo);
 
static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
                                             TypeSourceInfo *&ReturnTypeInfo) {
  Sema &SemaRef = state.getSema();
  Declarator &D = state.getDeclarator();
  QualType T;
  ReturnTypeInfo = nullptr;
 
  // The TagDecl owned by the DeclSpec.
  TagDecl *OwnedTagDecl = nullptr;
 
  switch (D.getName().getKind()) {
  case UnqualifiedIdKind::IK_ImplicitSelfParam:
  case UnqualifiedIdKind::IK_OperatorFunctionId:
  case UnqualifiedIdKind::IK_Identifier:
  case UnqualifiedIdKind::IK_LiteralOperatorId:
  case UnqualifiedIdKind::IK_TemplateId:
    T = ConvertDeclSpecToType(state);
 
    if (!D.isInvalidType() && D.getDeclSpec().isTypeSpecOwned()) {
      OwnedTagDecl = cast<TagDecl>(D.getDeclSpec().getRepAsDecl());
      // Owned declaration is embedded in declarator.
      OwnedTagDecl->setEmbeddedInDeclarator(true);
    }
    break;
 
  case UnqualifiedIdKind::IK_ConstructorName:
  case UnqualifiedIdKind::IK_ConstructorTemplateId:
  case UnqualifiedIdKind::IK_DestructorName:
    // Constructors and destructors don't have return types. Use
    // "void" instead.
    T = SemaRef.Context.VoidTy;
    processTypeAttrs(state, T, TAL_DeclSpec,
                     D.getMutableDeclSpec().getAttributes());
    break;
 
  case UnqualifiedIdKind::IK_DeductionGuideName:
    // Deduction guides have a trailing return type and no type in their
    // decl-specifier sequence. Use a placeholder return type for now.
    T = SemaRef.Context.DependentTy;
    break;
 
  case UnqualifiedIdKind::IK_ConversionFunctionId:
    // The result type of a conversion function is the type that it
    // converts to.
    T = SemaRef.GetTypeFromParser(D.getName().ConversionFunctionId,
                                  &ReturnTypeInfo);
    break;
  }
 
  // Note: We don't need to distribute declaration attributes (i.e.
  // D.getDeclarationAttributes()) because those are always C++11 attributes,
  // and those don't get distributed.
  distributeTypeAttrsFromDeclarator(state, T);
 
  // Find the deduced type in this type. Look in the trailing return type if we
  // have one, otherwise in the DeclSpec type.
  // FIXME: The standard wording doesn't currently describe this.
  DeducedType *Deduced = T->getContainedDeducedType();
  bool DeducedIsTrailingReturnType = false;
  if (Deduced && isa<AutoType>(Deduced) && D.hasTrailingReturnType()) {
    QualType T = SemaRef.GetTypeFromParser(D.getTrailingReturnType());
    Deduced = T.isNull() ? nullptr : T->getContainedDeducedType();
    DeducedIsTrailingReturnType = true;
  }
 
  // C++11 [dcl.spec.auto]p5: reject 'auto' if it is not in an allowed context.
  if (Deduced) {
    AutoType *Auto = dyn_cast<AutoType>(Deduced);
    int Error = -1;
 
    // Is this a 'auto' or 'decltype(auto)' type (as opposed to __auto_type or
    // class template argument deduction)?
    bool IsCXXAutoType =
        (Auto && Auto->getKeyword() != AutoTypeKeyword::GNUAutoType);
    bool IsDeducedReturnType = false;
 
    switch (D.getContext()) {
    case DeclaratorContext::LambdaExpr:
      // Declared return type of a lambda-declarator is implicit and is always
      // 'auto'.
      break;
    case DeclaratorContext::ObjCParameter:
    case DeclaratorContext::ObjCResult:
      Error = 0;
      break;
    case DeclaratorContext::RequiresExpr:
      Error = 22;
      break;
    case DeclaratorContext::Prototype:
    case DeclaratorContext::LambdaExprParameter: {
      InventedTemplateParameterInfo *Info = nullptr;
      if (D.getContext() == DeclaratorContext::Prototype) {
        // With concepts we allow 'auto' in function parameters.
        if (!SemaRef.getLangOpts().CPlusPlus20 || !Auto ||
            Auto->getKeyword() != AutoTypeKeyword::Auto) {
          Error = 0;
          break;
        } else if (!SemaRef.getCurScope()->isFunctionDeclarationScope()) {
          Error = 21;
          break;
        }
 
        Info = &SemaRef.InventedParameterInfos.back();
      } else {
        // In C++14, generic lambdas allow 'auto' in their parameters.
        if (!SemaRef.getLangOpts().CPlusPlus14 || !Auto ||
            Auto->getKeyword() != AutoTypeKeyword::Auto) {
          Error = 16;
          break;
        }
        Info = SemaRef.getCurLambda();
        assert(Info && "No LambdaScopeInfo on the stack!");
      }
 
      // We'll deal with inventing template parameters for 'auto' in trailing
      // return types when we pick up the trailing return type when processing
      // the function chunk.
      if (!DeducedIsTrailingReturnType)
        T = InventTemplateParameter(state, T, nullptr, Auto, *Info).first;
      break;
    }
    case DeclaratorContext::Member: {
      if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_static ||
          D.isFunctionDeclarator())
        break;
      bool Cxx = SemaRef.getLangOpts().CPlusPlus;
      if (isa<ObjCContainerDecl>(SemaRef.CurContext)) {
        Error = 6; // Interface member.
      } else {
        switch (cast<TagDecl>(SemaRef.CurContext)->getTagKind()) {
        case TTK_Enum: llvm_unreachable("unhandled tag kind");
        case TTK_Struct: Error = Cxx ? 1 : 2; /* Struct member */ break;
        case TTK_Union:  Error = Cxx ? 3 : 4; /* Union member */ break;
        case TTK_Class:  Error = 5; /* Class member */ break;
        case TTK_Interface: Error = 6; /* Interface member */ break;
        }
      }
      if (D.getDeclSpec().isFriendSpecified())
        Error = 20; // Friend type
      break;
    }
    case DeclaratorContext::CXXCatch:
    case DeclaratorContext::ObjCCatch:
      Error = 7; // Exception declaration
      break;
    case DeclaratorContext::TemplateParam:
      if (isa<DeducedTemplateSpecializationType>(Deduced) &&
          !SemaRef.getLangOpts().CPlusPlus20)
        Error = 19; // Template parameter (until C++20)
      else if (!SemaRef.getLangOpts().CPlusPlus17)
        Error = 8; // Template parameter (until C++17)
      break;
    case DeclaratorContext::BlockLiteral:
      Error = 9; // Block literal
      break;
    case DeclaratorContext::TemplateArg:
      // Within a template argument list, a deduced template specialization
      // type will be reinterpreted as a template template argument.
      if (isa<DeducedTemplateSpecializationType>(Deduced) &&
          !D.getNumTypeObjects() &&
          D.getDeclSpec().getParsedSpecifiers() == DeclSpec::PQ_TypeSpecifier)
        break;
      [[fallthrough]];
    case DeclaratorContext::TemplateTypeArg:
      Error = 10; // Template type argument
      break;
    case DeclaratorContext::AliasDecl:
    case DeclaratorContext::AliasTemplate:
      Error = 12; // Type alias
      break;
    case DeclaratorContext::TrailingReturn:
    case DeclaratorContext::TrailingReturnVar:
      if (!SemaRef.getLangOpts().CPlusPlus14 || !IsCXXAutoType)
        Error = 13; // Function return type
      IsDeducedReturnType = true;
      break;
    case DeclaratorContext::ConversionId:
      if (!SemaRef.getLangOpts().CPlusPlus14 || !IsCXXAutoType)
        Error = 14; // conversion-type-id
      IsDeducedReturnType = true;
      break;
    case DeclaratorContext::FunctionalCast:
      if (isa<DeducedTemplateSpecializationType>(Deduced))
        break;
      if (SemaRef.getLangOpts().CPlusPlus2b && IsCXXAutoType &&
          !Auto->isDecltypeAuto())
        break; // auto(x)
      [[fallthrough]];
    case DeclaratorContext::TypeName:
    case DeclaratorContext::Association:
      Error = 15; // Generic
      break;
    case DeclaratorContext::File:
    case DeclaratorContext::Block:
    case DeclaratorContext::ForInit:
    case DeclaratorContext::SelectionInit:
    case DeclaratorContext::Condition:
      // FIXME: P0091R3 (erroneously) does not permit class template argument
      // deduction in conditions, for-init-statements, and other declarations
      // that are not simple-declarations.
      break;
    case DeclaratorContext::CXXNew:
      // FIXME: P0091R3 does not permit class template argument deduction here,
      // but we follow GCC and allow it anyway.
      if (!IsCXXAutoType && !isa<DeducedTemplateSpecializationType>(Deduced))
        Error = 17; // 'new' type
      break;
    case DeclaratorContext::KNRTypeList:
      Error = 18; // K&R function parameter
      break;
    }
 
    if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef)
      Error = 11;
 
    // In Objective-C it is an error to use 'auto' on a function declarator
    // (and everywhere for '__auto_type').
    if (D.isFunctionDeclarator() &&
        (!SemaRef.getLangOpts().CPlusPlus11 || !IsCXXAutoType))
      Error = 13;
 
    SourceRange AutoRange = D.getDeclSpec().getTypeSpecTypeLoc();
    if (D.getName().getKind() == UnqualifiedIdKind::IK_ConversionFunctionId)
      AutoRange = D.getName().getSourceRange();
 
    if (Error != -1) {
      unsigned Kind;
      if (Auto) {
        switch (Auto->getKeyword()) {
        case AutoTypeKeyword::Auto: Kind = 0; break;
        case AutoTypeKeyword::DecltypeAuto: Kind = 1; break;
        case AutoTypeKeyword::GNUAutoType: Kind = 2; break;
        }
      } else {
        assert(isa<DeducedTemplateSpecializationType>(Deduced) &&
               "unknown auto type");
        Kind = 3;
      }
 
      auto *DTST = dyn_cast<DeducedTemplateSpecializationType>(Deduced);
      TemplateName TN = DTST ? DTST->getTemplateName() : TemplateName();
 
      SemaRef.Diag(AutoRange.getBegin(), diag::err_auto_not_allowed)
        << Kind << Error << (int)SemaRef.getTemplateNameKindForDiagnostics(TN)
        << QualType(Deduced, 0) << AutoRange;
      if (auto *TD = TN.getAsTemplateDecl())
        SemaRef.Diag(TD->getLocation(), diag::note_template_decl_here);
 
      T = SemaRef.Context.IntTy;
      D.setInvalidType(true);
    } else if (Auto && D.getContext() != DeclaratorContext::LambdaExpr) {
      // If there was a trailing return type, we already got
      // warn_cxx98_compat_trailing_return_type in the parser.
      SemaRef.Diag(AutoRange.getBegin(),
                   D.getContext() == DeclaratorContext::LambdaExprParameter
                       ? diag::warn_cxx11_compat_generic_lambda
                   : IsDeducedReturnType
                       ? diag::warn_cxx11_compat_deduced_return_type
                       : diag::warn_cxx98_compat_auto_type_specifier)
          << AutoRange;
    }
  }
 
  if (SemaRef.getLangOpts().CPlusPlus &&
      OwnedTagDecl && OwnedTagDecl->isCompleteDefinition()) {
    // Check the contexts where C++ forbids the declaration of a new class
    // or enumeration in a type-specifier-seq.
    unsigned DiagID = 0;
    switch (D.getContext()) {
    case DeclaratorContext::TrailingReturn:
    case DeclaratorContext::TrailingReturnVar:
      // Class and enumeration definitions are syntactically not allowed in
      // trailing return types.
      llvm_unreachable("parser should not have allowed this");
      break;
    case DeclaratorContext::File:
    case DeclaratorContext::Member:
    case DeclaratorContext::Block:
    case DeclaratorContext::ForInit:
    case DeclaratorContext::SelectionInit:
    case DeclaratorContext::BlockLiteral:
    case DeclaratorContext::LambdaExpr:
      // C++11 [dcl.type]p3:
      //   A type-specifier-seq shall not define a class or enumeration unless
      //   it appears in the type-id of an alias-declaration (7.1.3) that is not
      //   the declaration of a template-declaration.
    case DeclaratorContext::AliasDecl:
      break;
    case DeclaratorContext::AliasTemplate:
      DiagID = diag::err_type_defined_in_alias_template;
      break;
    case DeclaratorContext::TypeName:
    case DeclaratorContext::FunctionalCast:
    case DeclaratorContext::ConversionId:
    case DeclaratorContext::TemplateParam:
    case DeclaratorContext::CXXNew:
    case DeclaratorContext::CXXCatch:
    case DeclaratorContext::ObjCCatch:
    case DeclaratorContext::TemplateArg:
    case DeclaratorContext::TemplateTypeArg:
    case DeclaratorContext::Association:
      DiagID = diag::err_type_defined_in_type_specifier;
      break;
    case DeclaratorContext::Prototype:
    case DeclaratorContext::LambdaExprParameter:
    case DeclaratorContext::ObjCParameter:
    case DeclaratorContext::ObjCResult:
    case DeclaratorContext::KNRTypeList:
    case DeclaratorContext::RequiresExpr:
      // C++ [dcl.fct]p6:
      //   Types shall not be defined in return or parameter types.
      DiagID = diag::err_type_defined_in_param_type;
      break;
    case DeclaratorContext::Condition:
      // C++ 6.4p2:
      // The type-specifier-seq shall not contain typedef and shall not declare
      // a new class or enumeration.
      DiagID = diag::err_type_defined_in_condition;
      break;
    }
 
    if (DiagID != 0) {
      SemaRef.Diag(OwnedTagDecl->getLocation(), DiagID)
          << SemaRef.Context.getTypeDeclType(OwnedTagDecl);
      D.setInvalidType(true);
    }
  }
 
  assert(!T.isNull() && "This function should not return a null type");
  return T;
}
 
/// Produce an appropriate diagnostic for an ambiguity between a function
/// declarator and a C++ direct-initializer.
static void warnAboutAmbiguousFunction(Sema &S, Declarator &D,
                                       DeclaratorChunk &DeclType, QualType RT) {
  const DeclaratorChunk::FunctionTypeInfo &FTI = DeclType.Fun;
  assert(FTI.isAmbiguous && "no direct-initializer / function ambiguity");
 
  // If the return type is void there is no ambiguity.
  if (RT->isVoidType())
    return;
 
  // An initializer for a non-class type can have at most one argument.
  if (!RT->isRecordType() && FTI.NumParams > 1)
    return;
 
  // An initializer for a reference must have exactly one argument.
  if (RT->isReferenceType() && FTI.NumParams != 1)
    return;
 
  // Only warn if this declarator is declaring a function at block scope, and
  // doesn't have a storage class (such as 'extern') specified.
  if (!D.isFunctionDeclarator() ||
      D.getFunctionDefinitionKind() != FunctionDefinitionKind::Declaration ||
      !S.CurContext->isFunctionOrMethod() ||
      D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_unspecified)
    return;
 
  // Inside a condition, a direct initializer is not permitted. We allow one to
  // be parsed in order to give better diagnostics in condition parsing.
  if (D.getContext() == DeclaratorContext::Condition)
    return;
 
  SourceRange ParenRange(DeclType.Loc, DeclType.EndLoc);
 
  S.Diag(DeclType.Loc,
         FTI.NumParams ? diag::warn_parens_disambiguated_as_function_declaration
                       : diag::warn_empty_parens_are_function_decl)
      << ParenRange;
 
  // If the declaration looks like:
  //   T var1,
  //   f();
  // and name lookup finds a function named 'f', then the ',' was
  // probably intended to be a ';'.
  if (!D.isFirstDeclarator() && D.getIdentifier()) {
    FullSourceLoc Comma(D.getCommaLoc(), S.SourceMgr);
    FullSourceLoc Name(D.getIdentifierLoc(), S.SourceMgr);
    if (Comma.getFileID() != Name.getFileID() ||
        Comma.getSpellingLineNumber() != Name.getSpellingLineNumber()) {
      LookupResult Result(S, D.getIdentifier(), SourceLocation(),
                          Sema::LookupOrdinaryName);
      if (S.LookupName(Result, S.getCurScope()))
        S.Diag(D.getCommaLoc(), diag::note_empty_parens_function_call)
          << FixItHint::CreateReplacement(D.getCommaLoc(), ";")
          << D.getIdentifier();
      Result.suppressDiagnostics();
    }
  }
 
  if (FTI.NumParams > 0) {
    // For a declaration with parameters, eg. "T var(T());", suggest adding
    // parens around the first parameter to turn the declaration into a
    // variable declaration.
    SourceRange Range = FTI.Params[0].Param->getSourceRange();
    SourceLocation B = Range.getBegin();
    SourceLocation E = S.getLocForEndOfToken(Range.getEnd());
    // FIXME: Maybe we should suggest adding braces instead of parens
    // in C++11 for classes that don't have an initializer_list constructor.
    S.Diag(B, diag::note_additional_parens_for_variable_declaration)
      << FixItHint::CreateInsertion(B, "(")
      << FixItHint::CreateInsertion(E, ")");
  } else {
    // For a declaration without parameters, eg. "T var();", suggest replacing
    // the parens with an initializer to turn the declaration into a variable
    // declaration.
    const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
 
    // Empty parens mean value-initialization, and no parens mean
    // default initialization. These are equivalent if the default
    // constructor is user-provided or if zero-initialization is a
    // no-op.
    if (RD && RD->hasDefinition() &&
        (RD->isEmpty() || RD->hasUserProvidedDefaultConstructor()))
      S.Diag(DeclType.Loc, diag::note_empty_parens_default_ctor)
        << FixItHint::CreateRemoval(ParenRange);
    else {
      std::string Init =
          S.getFixItZeroInitializerForType(RT, ParenRange.getBegin());
      if (Init.empty() && S.LangOpts.CPlusPlus11)
        Init = "{}";
      if (!Init.empty())
        S.Diag(DeclType.Loc, diag::note_empty_parens_zero_initialize)
          << FixItHint::CreateReplacement(ParenRange, Init);
    }
  }
}
 
/// Produce an appropriate diagnostic for a declarator with top-level
/// parentheses.
static void warnAboutRedundantParens(Sema &S, Declarator &D, QualType T) {
  DeclaratorChunk &Paren = D.getTypeObject(D.getNumTypeObjects() - 1);
  assert(Paren.Kind == DeclaratorChunk::Paren &&
         "do not have redundant top-level parentheses");
 
  // This is a syntactic check; we're not interested in cases that arise
  // during template instantiation.
  if (S.inTemplateInstantiation())
    return;
 
  // Check whether this could be intended to be a construction of a temporary
  // object in C++ via a function-style cast.
  bool CouldBeTemporaryObject =
      S.getLangOpts().CPlusPlus && D.isExpressionContext() &&
      !D.isInvalidType() && D.getIdentifier() &&
      D.getDeclSpec().getParsedSpecifiers() == DeclSpec::PQ_TypeSpecifier &&
      (T->isRecordType() || T->isDependentType()) &&
      D.getDeclSpec().getTypeQualifiers() == 0 && D.isFirstDeclarator();
 
  bool StartsWithDeclaratorId = true;
  for (auto &C : D.type_objects()) {
    switch (C.Kind) {
    case DeclaratorChunk::Paren:
      if (&C == &Paren)
        continue;
      [[fallthrough]];
    case DeclaratorChunk::Pointer:
      StartsWithDeclaratorId = false;
      continue;
 
    case DeclaratorChunk::Array:
      if (!C.Arr.NumElts)
        CouldBeTemporaryObject = false;
      continue;
 
    case DeclaratorChunk::Reference:
      // FIXME: Suppress the warning here if there is no initializer; we're
      // going to give an error anyway.
      // We assume that something like 'T (&x) = y;' is highly likely to not
      // be intended to be a temporary object.
      CouldBeTemporaryObject = false;
      StartsWithDeclaratorId = false;
      continue;
 
    case DeclaratorChunk::Function:
      // In a new-type-id, function chunks require parentheses.
      if (D.getContext() == DeclaratorContext::CXXNew)
        return;
      // FIXME: "A(f())" deserves a vexing-parse warning, not just a
      // redundant-parens warning, but we don't know whether the function
      // chunk was syntactically valid as an expression here.
      CouldBeTemporaryObject = false;
      continue;
 
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Pipe:
      // These cannot appear in expressions.
      CouldBeTemporaryObject = false;
      StartsWithDeclaratorId = false;
      continue;
    }
  }
 
  // FIXME: If there is an initializer, assume that this is not intended to be
  // a construction of a temporary object.
 
  // Check whether the name has already been declared; if not, this is not a
  // function-style cast.
  if (CouldBeTemporaryObject) {
    LookupResult Result(S, D.getIdentifier(), SourceLocation(),
                        Sema::LookupOrdinaryName);
    if (!S.LookupName(Result, S.getCurScope()))
      CouldBeTemporaryObject = false;
    Result.suppressDiagnostics();
  }
 
  SourceRange ParenRange(Paren.Loc, Paren.EndLoc);
 
  if (!CouldBeTemporaryObject) {
    // If we have A (::B), the parentheses affect the meaning of the program.
    // Suppress the warning in that case. Don't bother looking at the DeclSpec
    // here: even (e.g.) "int ::x" is visually ambiguous even though it's
    // formally unambiguous.
    if (StartsWithDeclaratorId && D.getCXXScopeSpec().isValid()) {
      for (NestedNameSpecifier *NNS = D.getCXXScopeSpec().getScopeRep(); NNS;
           NNS = NNS->getPrefix()) {
        if (NNS->getKind() == NestedNameSpecifier::Global)
          return;
      }
    }
 
    S.Diag(Paren.Loc, diag::warn_redundant_parens_around_declarator)
        << ParenRange << FixItHint::CreateRemoval(Paren.Loc)
        << FixItHint::CreateRemoval(Paren.EndLoc);
    return;
  }
 
  S.Diag(Paren.Loc, diag::warn_parens_disambiguated_as_variable_declaration)
      << ParenRange << D.getIdentifier();
  auto *RD = T->getAsCXXRecordDecl();
  if (!RD || !RD->hasDefinition() || RD->hasNonTrivialDestructor())
    S.Diag(Paren.Loc, diag::note_raii_guard_add_name)
        << FixItHint::CreateInsertion(Paren.Loc, " varname") << T
        << D.getIdentifier();
  // FIXME: A cast to void is probably a better suggestion in cases where it's
  // valid (when there is no initializer and we're not in a condition).
  S.Diag(D.getBeginLoc(), diag::note_function_style_cast_add_parentheses)
      << FixItHint::CreateInsertion(D.getBeginLoc(), "(")
      << FixItHint::CreateInsertion(S.getLocForEndOfToken(D.getEndLoc()), ")");
  S.Diag(Paren.Loc, diag::note_remove_parens_for_variable_declaration)
      << FixItHint::CreateRemoval(Paren.Loc)
      << FixItHint::CreateRemoval(Paren.EndLoc);
}
 
/// Helper for figuring out the default CC for a function declarator type.  If
/// this is the outermost chunk, then we can determine the CC from the
/// declarator context.  If not, then this could be either a member function
/// type or normal function type.
static CallingConv getCCForDeclaratorChunk(
    Sema &S, Declarator &D, const ParsedAttributesView &AttrList,
    const DeclaratorChunk::FunctionTypeInfo &FTI, unsigned ChunkIndex) {
  assert(D.getTypeObject(ChunkIndex).Kind == DeclaratorChunk::Function);
 
  // Check for an explicit CC attribute.
  for (const ParsedAttr &AL : AttrList) {
    switch (AL.getKind()) {
    CALLING_CONV_ATTRS_CASELIST : {
      // Ignore attributes that don't validate or can't apply to the
      // function type.  We'll diagnose the failure to apply them in
      // handleFunctionTypeAttr.
      CallingConv CC;
      if (!S.CheckCallingConvAttr(AL, CC) &&
          (!FTI.isVariadic || supportsVariadicCall(CC))) {
        return CC;
      }
      break;
    }
 
    default:
      break;
    }
  }
 
  bool IsCXXInstanceMethod = false;
 
  if (S.getLangOpts().CPlusPlus) {
    // Look inwards through parentheses to see if this chunk will form a
    // member pointer type or if we're the declarator.  Any type attributes
    // between here and there will override the CC we choose here.
    unsigned I = ChunkIndex;
    bool FoundNonParen = false;
    while (I && !FoundNonParen) {
      --I;
      if (D.getTypeObject(I).Kind != DeclaratorChunk::Paren)
        FoundNonParen = true;
    }
 
    if (FoundNonParen) {
      // If we're not the declarator, we're a regular function type unless we're
      // in a member pointer.
      IsCXXInstanceMethod =
          D.getTypeObject(I).Kind == DeclaratorChunk::MemberPointer;
    } else if (D.getContext() == DeclaratorContext::LambdaExpr) {
      // This can only be a call operator for a lambda, which is an instance
      // method.
      IsCXXInstanceMethod = true;
    } else {
      // We're the innermost decl chunk, so must be a function declarator.
      assert(D.isFunctionDeclarator());
 
      // If we're inside a record, we're declaring a method, but it could be
      // explicitly or implicitly static.
      IsCXXInstanceMethod =
          D.isFirstDeclarationOfMember() &&
          D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
          !D.isStaticMember();
    }
  }
 
  CallingConv CC = S.Context.getDefaultCallingConvention(FTI.isVariadic,
                                                         IsCXXInstanceMethod);
 
  // Attribute AT_OpenCLKernel affects the calling convention for SPIR
  // and AMDGPU targets, hence it cannot be treated as a calling
  // convention attribute. This is the simplest place to infer
  // calling convention for OpenCL kernels.
  if (S.getLangOpts().OpenCL) {
    for (const ParsedAttr &AL : D.getDeclSpec().getAttributes()) {
      if (AL.getKind() == ParsedAttr::AT_OpenCLKernel) {
        CC = CC_OpenCLKernel;
        break;
      }
    }
  } else if (S.getLangOpts().CUDA) {
    // If we're compiling CUDA/HIP code and targeting SPIR-V we need to make
    // sure the kernels will be marked with the right calling convention so that
    // they will be visible by the APIs that ingest SPIR-V.
    llvm::Triple Triple = S.Context.getTargetInfo().getTriple();
    if (Triple.getArch() == llvm::Triple::spirv32 ||
        Triple.getArch() == llvm::Triple::spirv64) {
      for (const ParsedAttr &AL : D.getDeclSpec().getAttributes()) {
        if (AL.getKind() == ParsedAttr::AT_CUDAGlobal) {
          CC = CC_OpenCLKernel;
          break;
        }
      }
    }
  }
 
  return CC;
}
 
namespace {
  /// A simple notion of pointer kinds, which matches up with the various
  /// pointer declarators.
  enum class SimplePointerKind {
    Pointer,
    BlockPointer,
    MemberPointer,
    Array,
  };
} // end anonymous namespace
 
IdentifierInfo *Sema::getNullabilityKeyword(NullabilityKind nullability) {
  switch (nullability) {
  case NullabilityKind::NonNull:
    if (!Ident__Nonnull)
      Ident__Nonnull = PP.getIdentifierInfo("_Nonnull");
    return Ident__Nonnull;
 
  case NullabilityKind::Nullable:
    if (!Ident__Nullable)
      Ident__Nullable = PP.getIdentifierInfo("_Nullable");
    return Ident__Nullable;
 
  case NullabilityKind::NullableResult:
    if (!Ident__Nullable_result)
      Ident__Nullable_result = PP.getIdentifierInfo("_Nullable_result");
    return Ident__Nullable_result;
 
  case NullabilityKind::Unspecified:
    if (!Ident__Null_unspecified)
      Ident__Null_unspecified = PP.getIdentifierInfo("_Null_unspecified");
    return Ident__Null_unspecified;
  }
  llvm_unreachable("Unknown nullability kind.");
}
 
/// Retrieve the identifier "NSError".
IdentifierInfo *Sema::getNSErrorIdent() {
  if (!Ident_NSError)
    Ident_NSError = PP.getIdentifierInfo("NSError");
 
  return Ident_NSError;
}
 
/// Check whether there is a nullability attribute of any kind in the given
/// attribute list.
static bool hasNullabilityAttr(const ParsedAttributesView &attrs) {
  for (const ParsedAttr &AL : attrs) {
    if (AL.getKind() == ParsedAttr::AT_TypeNonNull ||
        AL.getKind() == ParsedAttr::AT_TypeNullable ||
        AL.getKind() == ParsedAttr::AT_TypeNullableResult ||
        AL.getKind() == ParsedAttr::AT_TypeNullUnspecified)
      return true;
  }
 
  return false;
}
 
namespace {
  /// Describes the kind of a pointer a declarator describes.
  enum class PointerDeclaratorKind {
    // Not a pointer.
    NonPointer,
    // Single-level pointer.
    SingleLevelPointer,
    // Multi-level pointer (of any pointer kind).
    MultiLevelPointer,
    // CFFooRef*
    MaybePointerToCFRef,
    // CFErrorRef*
    CFErrorRefPointer,
    // NSError**
    NSErrorPointerPointer,
  };
 
  /// Describes a declarator chunk wrapping a pointer that marks inference as
  /// unexpected.
  // These values must be kept in sync with diagnostics.
  enum class PointerWrappingDeclaratorKind {
    /// Pointer is top-level.
    None = -1,
    /// Pointer is an array element.
    Array = 0,
    /// Pointer is the referent type of a C++ reference.
    Reference = 1
  };
} // end anonymous namespace
 
/// Classify the given declarator, whose type-specified is \c type, based on
/// what kind of pointer it refers to.
///
/// This is used to determine the default nullability.
static PointerDeclaratorKind
classifyPointerDeclarator(Sema &S, QualType type, Declarator &declarator,
                          PointerWrappingDeclaratorKind &wrappingKind) {
  unsigned numNormalPointers = 0;
 
  // For any dependent type, we consider it a non-pointer.
  if (type->isDependentType())
    return PointerDeclaratorKind::NonPointer;
 
  // Look through the declarator chunks to identify pointers.
  for (unsigned i = 0, n = declarator.getNumTypeObjects(); i != n; ++i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i);
    switch (chunk.Kind) {
    case DeclaratorChunk::Array:
      if (numNormalPointers == 0)
        wrappingKind = PointerWrappingDeclaratorKind::Array;
      break;
 
    case DeclaratorChunk::Function:
    case DeclaratorChunk::Pipe:
      break;
 
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::MemberPointer:
      return numNormalPointers > 0 ? PointerDeclaratorKind::MultiLevelPointer
                                   : PointerDeclaratorKind::SingleLevelPointer;
 
    case DeclaratorChunk::Paren:
      break;
 
    case DeclaratorChunk::Reference:
      if (numNormalPointers == 0)
        wrappingKind = PointerWrappingDeclaratorKind::Reference;
      break;
 
    case DeclaratorChunk::Pointer:
      ++numNormalPointers;
      if (numNormalPointers > 2)
        return PointerDeclaratorKind::MultiLevelPointer;
      break;
    }
  }
 
  // Then, dig into the type specifier itself.
  unsigned numTypeSpecifierPointers = 0;
  do {
    // Decompose normal pointers.
    if (auto ptrType = type->getAs<PointerType>()) {
      ++numNormalPointers;
 
      if (numNormalPointers > 2)
        return PointerDeclaratorKind::MultiLevelPointer;
 
      type = ptrType->getPointeeType();
      ++numTypeSpecifierPointers;
      continue;
    }
 
    // Decompose block pointers.
    if (type->getAs<BlockPointerType>()) {
      return numNormalPointers > 0 ? PointerDeclaratorKind::MultiLevelPointer
                                   : PointerDeclaratorKind::SingleLevelPointer;
    }
 
    // Decompose member pointers.
    if (type->getAs<MemberPointerType>()) {
      return numNormalPointers > 0 ? PointerDeclaratorKind::MultiLevelPointer
                                   : PointerDeclaratorKind::SingleLevelPointer;
    }
 
    // Look at Objective-C object pointers.
    if (auto objcObjectPtr = type->getAs<ObjCObjectPointerType>()) {
      ++numNormalPointers;
      ++numTypeSpecifierPointers;
 
      // If this is NSError**, report that.
      if (auto objcClassDecl = objcObjectPtr->getInterfaceDecl()) {
        if (objcClassDecl->getIdentifier() == S.getNSErrorIdent() &&
            numNormalPointers == 2 && numTypeSpecifierPointers < 2) {
          return PointerDeclaratorKind::NSErrorPointerPointer;
        }
      }
 
      break;
    }
 
    // Look at Objective-C class types.
    if (auto objcClass = type->getAs<ObjCInterfaceType>()) {
      if (objcClass->getInterface()->getIdentifier() == S.getNSErrorIdent()) {
        if (numNormalPointers == 2 && numTypeSpecifierPointers < 2)
          return PointerDeclaratorKind::NSErrorPointerPointer;
      }
 
      break;
    }
 
    // If at this point we haven't seen a pointer, we won't see one.
    if (numNormalPointers == 0)
      return PointerDeclaratorKind::NonPointer;
 
    if (auto recordType = type->getAs<RecordType>()) {
      RecordDecl *recordDecl = recordType->getDecl();
 
      // If this is CFErrorRef*, report it as such.
      if (numNormalPointers == 2 && numTypeSpecifierPointers < 2 &&
          S.isCFError(recordDecl)) {
        return PointerDeclaratorKind::CFErrorRefPointer;
      }
      break;
    }
 
    break;
  } while (true);
 
  switch (numNormalPointers) {
  case 0:
    return PointerDeclaratorKind::NonPointer;
 
  case 1:
    return PointerDeclaratorKind::SingleLevelPointer;
 
  case 2:
    return PointerDeclaratorKind::MaybePointerToCFRef;
 
  default:
    return PointerDeclaratorKind::MultiLevelPointer;
  }
}
 
bool Sema::isCFError(RecordDecl *RD) {
  // If we already know about CFError, test it directly.
  if (CFError)
    return CFError == RD;
 
  // Check whether this is CFError, which we identify based on its bridge to
  // NSError. CFErrorRef used to be declared with "objc_bridge" but is now
  // declared with "objc_bridge_mutable", so look for either one of the two
  // attributes.
  if (RD->getTagKind() == TTK_Struct) {
    IdentifierInfo *bridgedType = nullptr;
    if (auto bridgeAttr = RD->getAttr<ObjCBridgeAttr>())
      bridgedType = bridgeAttr->getBridgedType();
    else if (auto bridgeAttr = RD->getAttr<ObjCBridgeMutableAttr>())
      bridgedType = bridgeAttr->getBridgedType();
 
    if (bridgedType == getNSErrorIdent()) {
      CFError = RD;
      return true;
    }
  }
 
  return false;
}
 
static FileID getNullabilityCompletenessCheckFileID(Sema &S,
                                                    SourceLocation loc) {
  // If we're anywhere in a function, method, or closure context, don't perform
  // completeness checks.
  for (DeclContext *ctx = S.CurContext; ctx; ctx = ctx->getParent()) {
    if (ctx->isFunctionOrMethod())
      return FileID();
 
    if (ctx->isFileContext())
      break;
  }
 
  // We only care about the expansion location.
  loc = S.SourceMgr.getExpansionLoc(loc);
  FileID file = S.SourceMgr.getFileID(loc);
  if (file.isInvalid())
    return FileID();
 
  // Retrieve file information.
  bool invalid = false;
  const SrcMgr::SLocEntry &sloc = S.SourceMgr.getSLocEntry(file, &invalid);
  if (invalid || !sloc.isFile())
    return FileID();
 
  // We don't want to perform completeness checks on the main file or in
  // system headers.
  const SrcMgr::FileInfo &fileInfo = sloc.getFile();
  if (fileInfo.getIncludeLoc().isInvalid())
    return FileID();
  if (fileInfo.getFileCharacteristic() != SrcMgr::C_User &&
      S.Diags.getSuppressSystemWarnings()) {
    return FileID();
  }
 
  return file;
}
 
/// Creates a fix-it to insert a C-style nullability keyword at \p pointerLoc,
/// taking into account whitespace before and after.
template <typename DiagBuilderT>
static void fixItNullability(Sema &S, DiagBuilderT &Diag,
                             SourceLocation PointerLoc,
                             NullabilityKind Nullability) {
  assert(PointerLoc.isValid());
  if (PointerLoc.isMacroID())
    return;
 
  SourceLocation FixItLoc = S.getLocForEndOfToken(PointerLoc);
  if (!FixItLoc.isValid() || FixItLoc == PointerLoc)
    return;
 
  const char *NextChar = S.SourceMgr.getCharacterData(FixItLoc);
  if (!NextChar)
    return;
 
  SmallString<32> InsertionTextBuf{" "};
  InsertionTextBuf += getNullabilitySpelling(Nullability);
  InsertionTextBuf += " ";
  StringRef InsertionText = InsertionTextBuf.str();
 
  if (isWhitespace(*NextChar)) {
    InsertionText = InsertionText.drop_back();
  } else if (NextChar[-1] == '[') {
    if (NextChar[0] == ']')
      InsertionText = InsertionText.drop_back().drop_front();
    else
      InsertionText = InsertionText.drop_front();
  } else if (!isAsciiIdentifierContinue(NextChar[0], /*allow dollar*/ true) &&
             !isAsciiIdentifierContinue(NextChar[-1], /*allow dollar*/ true)) {
    InsertionText = InsertionText.drop_back().drop_front();
  }
 
  Diag << FixItHint::CreateInsertion(FixItLoc, InsertionText);
}
 
static void emitNullabilityConsistencyWarning(Sema &S,
                                              SimplePointerKind PointerKind,
                                              SourceLocation PointerLoc,
                                              SourceLocation PointerEndLoc) {
  assert(PointerLoc.isValid());
 
  if (PointerKind == SimplePointerKind::Array) {
    S.Diag(PointerLoc, diag::warn_nullability_missing_array);
  } else {
    S.Diag(PointerLoc, diag::warn_nullability_missing)
      << static_cast<unsigned>(PointerKind);
  }
 
  auto FixItLoc = PointerEndLoc.isValid() ? PointerEndLoc : PointerLoc;
  if (FixItLoc.isMacroID())
    return;
 
  auto addFixIt = [&](NullabilityKind Nullability) {
    auto Diag = S.Diag(FixItLoc, diag::note_nullability_fix_it);
    Diag << static_cast<unsigned>(Nullability);
    Diag << static_cast<unsigned>(PointerKind);
    fixItNullability(S, Diag, FixItLoc, Nullability);
  };
  addFixIt(NullabilityKind::Nullable);
  addFixIt(NullabilityKind::NonNull);
}
 
/// Complains about missing nullability if the file containing \p pointerLoc
/// has other uses of nullability (either the keywords or the \c assume_nonnull
/// pragma).
///
/// If the file has \e not seen other uses of nullability, this particular
/// pointer is saved for possible later diagnosis. See recordNullabilitySeen().
static void
checkNullabilityConsistency(Sema &S, SimplePointerKind pointerKind,
                            SourceLocation pointerLoc,
                            SourceLocation pointerEndLoc = SourceLocation()) {
  // Determine which file we're performing consistency checking for.
  FileID file = getNullabilityCompletenessCheckFileID(S, pointerLoc);
  if (file.isInvalid())
    return;
 
  // If we haven't seen any type nullability in this file, we won't warn now
  // about anything.
  FileNullability &fileNullability = S.NullabilityMap[file];
  if (!fileNullability.SawTypeNullability) {
    // If this is the first pointer declarator in the file, and the appropriate
    // warning is on, record it in case we need to diagnose it retroactively.
    diag::kind diagKind;
    if (pointerKind == SimplePointerKind::Array)
      diagKind = diag::warn_nullability_missing_array;
    else
      diagKind = diag::warn_nullability_missing;
 
    if (fileNullability.PointerLoc.isInvalid() &&
        !S.Context.getDiagnostics().isIgnored(diagKind, pointerLoc)) {
      fileNullability.PointerLoc = pointerLoc;
      fileNullability.PointerEndLoc = pointerEndLoc;
      fileNullability.PointerKind = static_cast<unsigned>(pointerKind);
    }
 
    return;
  }
 
  // Complain about missing nullability.
  emitNullabilityConsistencyWarning(S, pointerKind, pointerLoc, pointerEndLoc);
}
 
/// Marks that a nullability feature has been used in the file containing
/// \p loc.
///
/// If this file already had pointer types in it that were missing nullability,
/// the first such instance is retroactively diagnosed.
///
/// \sa checkNullabilityConsistency
static void recordNullabilitySeen(Sema &S, SourceLocation loc) {
  FileID file = getNullabilityCompletenessCheckFileID(S, loc);
  if (file.isInvalid())
    return;
 
  FileNullability &fileNullability = S.NullabilityMap[file];
  if (fileNullability.SawTypeNullability)
    return;
  fileNullability.SawTypeNullability = true;
 
  // If we haven't seen any type nullability before, now we have. Retroactively
  // diagnose the first unannotated pointer, if there was one.
  if (fileNullability.PointerLoc.isInvalid())
    return;
 
  auto kind = static_cast<SimplePointerKind>(fileNullability.PointerKind);
  emitNullabilityConsistencyWarning(S, kind, fileNullability.PointerLoc,
                                    fileNullability.PointerEndLoc);
}
 
/// Returns true if any of the declarator chunks before \p endIndex include a
/// level of indirection: array, pointer, reference, or pointer-to-member.
///
/// Because declarator chunks are stored in outer-to-inner order, testing
/// every chunk before \p endIndex is testing all chunks that embed the current
/// chunk as part of their type.
///
/// It is legal to pass the result of Declarator::getNumTypeObjects() as the
/// end index, in which case all chunks are tested.
static bool hasOuterPointerLikeChunk(const Declarator &D, unsigned endIndex) {
  unsigned i = endIndex;
  while (i != 0) {
    // Walk outwards along the declarator chunks.
    --i;
    const DeclaratorChunk &DC = D.getTypeObject(i);
    switch (DC.Kind) {
    case DeclaratorChunk::Paren:
      break;
    case DeclaratorChunk::Array:
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
      return true;
    case DeclaratorChunk::Function:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Pipe:
      // These are invalid anyway, so just ignore.
      break;
    }
  }
  return false;
}
 
static bool IsNoDerefableChunk(DeclaratorChunk Chunk) {
  return (Chunk.Kind == DeclaratorChunk::Pointer ||
          Chunk.Kind == DeclaratorChunk::Array);
}
 
template<typename AttrT>
static AttrT *createSimpleAttr(ASTContext &Ctx, ParsedAttr &AL) {
  AL.setUsedAsTypeAttr();
  return ::new (Ctx) AttrT(Ctx, AL);
}
 
static Attr *createNullabilityAttr(ASTContext &Ctx, ParsedAttr &Attr,
                                   NullabilityKind NK) {
  switch (NK) {
  case NullabilityKind::NonNull:
    return createSimpleAttr<TypeNonNullAttr>(Ctx, Attr);
 
  case NullabilityKind::Nullable:
    return createSimpleAttr<TypeNullableAttr>(Ctx, Attr);
 
  case NullabilityKind::NullableResult:
    return createSimpleAttr<TypeNullableResultAttr>(Ctx, Attr);
 
  case NullabilityKind::Unspecified:
    return createSimpleAttr<TypeNullUnspecifiedAttr>(Ctx, Attr);
  }
  llvm_unreachable("unknown NullabilityKind");
}
 
// Diagnose whether this is a case with the multiple addr spaces.
// Returns true if this is an invalid case.
// ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified
// by qualifiers for two or more different address spaces."
static bool DiagnoseMultipleAddrSpaceAttributes(Sema &S, LangAS ASOld,
                                                LangAS ASNew,
                                                SourceLocation AttrLoc) {
  if (ASOld != LangAS::Default) {
    if (ASOld != ASNew) {
      S.Diag(AttrLoc, diag::err_attribute_address_multiple_qualifiers);
      return true;
    }
    // Emit a warning if they are identical; it's likely unintended.
    S.Diag(AttrLoc,
           diag::warn_attribute_address_multiple_identical_qualifiers);
  }
  return false;
}
 
static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
                                                QualType declSpecType,
                                                TypeSourceInfo *TInfo) {
  // The TypeSourceInfo that this function returns will not be a null type.
  // If there is an error, this function will fill in a dummy type as fallback.
  QualType T = declSpecType;
  Declarator &D = state.getDeclarator();
  Sema &S = state.getSema();
  ASTContext &Context = S.Context;
  const LangOptions &LangOpts = S.getLangOpts();
 
  // The name we're declaring, if any.
  DeclarationName Name;
  if (D.getIdentifier())
    Name = D.getIdentifier();
 
  // Does this declaration declare a typedef-name?
  bool IsTypedefName =
      D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef ||
      D.getContext() == DeclaratorContext::AliasDecl ||
      D.getContext() == DeclaratorContext::AliasTemplate;
 
  // Does T refer to a function type with a cv-qualifier or a ref-qualifier?
  bool IsQualifiedFunction = T->isFunctionProtoType() &&
      (!T->castAs<FunctionProtoType>()->getMethodQuals().empty() ||
       T->castAs<FunctionProtoType>()->getRefQualifier() != RQ_None);
 
  // If T is 'decltype(auto)', the only declarators we can have are parens
  // and at most one function declarator if this is a function declaration.
  // If T is a deduced class template specialization type, we can have no
  // declarator chunks at all.
  if (auto *DT = T->getAs<DeducedType>()) {
    const AutoType *AT = T->getAs<AutoType>();
    bool IsClassTemplateDeduction = isa<DeducedTemplateSpecializationType>(DT);
    if ((AT && AT->isDecltypeAuto()) || IsClassTemplateDeduction) {
      for (unsigned I = 0, E = D.getNumTypeObjects(); I != E; ++I) {
        unsigned Index = E - I - 1;
        DeclaratorChunk &DeclChunk = D.getTypeObject(Index);
        unsigned DiagId = IsClassTemplateDeduction
                              ? diag::err_deduced_class_template_compound_type
                              : diag::err_decltype_auto_compound_type;
        unsigned DiagKind = 0;
        switch (DeclChunk.Kind) {
        case DeclaratorChunk::Paren:
          // FIXME: Rejecting this is a little silly.
          if (IsClassTemplateDeduction) {
            DiagKind = 4;
            break;
          }
          continue;
        case DeclaratorChunk::Function: {
          if (IsClassTemplateDeduction) {
            DiagKind = 3;
            break;
          }
          unsigned FnIndex;
          if (D.isFunctionDeclarationContext() &&
              D.isFunctionDeclarator(FnIndex) && FnIndex == Index)
            continue;
          DiagId = diag::err_decltype_auto_function_declarator_not_declaration;
          break;
        }
        case DeclaratorChunk::Pointer:
        case DeclaratorChunk::BlockPointer:
        case DeclaratorChunk::MemberPointer:
          DiagKind = 0;
          break;
        case DeclaratorChunk::Reference:
          DiagKind = 1;
          break;
        case DeclaratorChunk::Array:
          DiagKind = 2;
          break;
        case DeclaratorChunk::Pipe:
          break;
        }
 
        S.Diag(DeclChunk.Loc, DiagId) << DiagKind;
        D.setInvalidType(true);
        break;
      }
    }
  }
 
  // Determine whether we should infer _Nonnull on pointer types.
  std::optional<NullabilityKind> inferNullability;
  bool inferNullabilityCS = false;
  bool inferNullabilityInnerOnly = false;
  bool inferNullabilityInnerOnlyComplete = false;
 
  // Are we in an assume-nonnull region?
  bool inAssumeNonNullRegion = false;
  SourceLocation assumeNonNullLoc = S.PP.getPragmaAssumeNonNullLoc();
  if (assumeNonNullLoc.isValid()) {
    inAssumeNonNullRegion = true;
    recordNullabilitySeen(S, assumeNonNullLoc);
  }
 
  // Whether to complain about missing nullability specifiers or not.
  enum {
    /// Never complain.
    CAMN_No,
    /// Complain on the inner pointers (but not the outermost
    /// pointer).
    CAMN_InnerPointers,
    /// Complain about any pointers that don't have nullability
    /// specified or inferred.
    CAMN_Yes
  } complainAboutMissingNullability = CAMN_No;
  unsigned NumPointersRemaining = 0;
  auto complainAboutInferringWithinChunk = PointerWrappingDeclaratorKind::None;
 
  if (IsTypedefName) {
    // For typedefs, we do not infer any nullability (the default),
    // and we only complain about missing nullability specifiers on
    // inner pointers.
    complainAboutMissingNullability = CAMN_InnerPointers;
 
    if (T->canHaveNullability(/*ResultIfUnknown*/ false) &&
        !T->getNullability()) {
      // Note that we allow but don't require nullability on dependent types.
      ++NumPointersRemaining;
    }
 
    for (unsigned i = 0, n = D.getNumTypeObjects(); i != n; ++i) {
      DeclaratorChunk &chunk = D.getTypeObject(i);
      switch (chunk.Kind) {
      case DeclaratorChunk::Array:
      case DeclaratorChunk::Function:
      case DeclaratorChunk::Pipe:
        break;
 
      case DeclaratorChunk::BlockPointer:
      case DeclaratorChunk::MemberPointer:
        ++NumPointersRemaining;
        break;
 
      case DeclaratorChunk::Paren:
      case DeclaratorChunk::Reference:
        continue;
 
      case DeclaratorChunk::Pointer:
        ++NumPointersRemaining;
        continue;
      }
    }
  } else {
    bool isFunctionOrMethod = false;
    switch (auto context = state.getDeclarator().getContext()) {
    case DeclaratorContext::ObjCParameter:
    case DeclaratorContext::ObjCResult:
    case DeclaratorContext::Prototype:
    case DeclaratorContext::TrailingReturn:
    case DeclaratorContext::TrailingReturnVar:
      isFunctionOrMethod = true;
      [[fallthrough]];
 
    case DeclaratorContext::Member:
      if (state.getDeclarator().isObjCIvar() && !isFunctionOrMethod) {
        complainAboutMissingNullability = CAMN_No;
        break;
      }
 
      // Weak properties are inferred to be nullable.
      if (state.getDeclarator().isObjCWeakProperty()) {
        // Weak properties cannot be nonnull, and should not complain about
        // missing nullable attributes during completeness checks.
        complainAboutMissingNullability = CAMN_No;
        if (inAssumeNonNullRegion) {
          inferNullability = NullabilityKind::Nullable;
        }
        break;
      }
 
      [[fallthrough]];
 
    case DeclaratorContext::File:
    case DeclaratorContext::KNRTypeList: {
      complainAboutMissingNullability = CAMN_Yes;
 
      // Nullability inference depends on the type and declarator.
      auto wrappingKind = PointerWrappingDeclaratorKind::None;
      switch (classifyPointerDeclarator(S, T, D, wrappingKind)) {
      case PointerDeclaratorKind::NonPointer:
      case PointerDeclaratorKind::MultiLevelPointer:
        // Cannot infer nullability.
        break;
 
      case PointerDeclaratorKind::SingleLevelPointer:
        // Infer _Nonnull if we are in an assumes-nonnull region.
        if (inAssumeNonNullRegion) {
          complainAboutInferringWithinChunk = wrappingKind;
          inferNullability = NullabilityKind::NonNull;
          inferNullabilityCS = (context == DeclaratorContext::ObjCParameter ||
                                context == DeclaratorContext::ObjCResult);
        }
        break;
 
      case PointerDeclaratorKind::CFErrorRefPointer:
      case PointerDeclaratorKind::NSErrorPointerPointer:
        // Within a function or method signature, infer _Nullable at both
        // levels.
        if (isFunctionOrMethod && inAssumeNonNullRegion)
          inferNullability = NullabilityKind::Nullable;
        break;
 
      case PointerDeclaratorKind::MaybePointerToCFRef:
        if (isFunctionOrMethod) {
          // On pointer-to-pointer parameters marked cf_returns_retained or
          // cf_returns_not_retained, if the outer pointer is explicit then
          // infer the inner pointer as _Nullable.
          auto hasCFReturnsAttr =
              [](const ParsedAttributesView &AttrList) -> bool {
            return AttrList.hasAttribute(ParsedAttr::AT_CFReturnsRetained) ||
                   AttrList.hasAttribute(ParsedAttr::AT_CFReturnsNotRetained);
          };
          if (const auto *InnermostChunk = D.getInnermostNonParenChunk()) {
            if (hasCFReturnsAttr(D.getDeclarationAttributes()) ||
                hasCFReturnsAttr(D.getAttributes()) ||
                hasCFReturnsAttr(InnermostChunk->getAttrs()) ||
                hasCFReturnsAttr(D.getDeclSpec().getAttributes())) {
              inferNullability = NullabilityKind::Nullable;
              inferNullabilityInnerOnly = true;
            }
          }
        }
        break;
      }
      break;
    }
 
    case DeclaratorContext::ConversionId:
      complainAboutMissingNullability = CAMN_Yes;
      break;
 
    case DeclaratorContext::AliasDecl:
    case DeclaratorContext::AliasTemplate:
    case DeclaratorContext::Block:
    case DeclaratorContext::BlockLiteral:
    case DeclaratorContext::Condition:
    case DeclaratorContext::CXXCatch:
    case DeclaratorContext::CXXNew:
    case DeclaratorContext::ForInit:
    case DeclaratorContext::SelectionInit:
    case DeclaratorContext::LambdaExpr:
    case DeclaratorContext::LambdaExprParameter:
    case DeclaratorContext::ObjCCatch:
    case DeclaratorContext::TemplateParam:
    case DeclaratorContext::TemplateArg:
    case DeclaratorContext::TemplateTypeArg:
    case DeclaratorContext::TypeName:
    case DeclaratorContext::FunctionalCast:
    case DeclaratorContext::RequiresExpr:
    case DeclaratorContext::Association:
      // Don't infer in these contexts.
      break;
    }
  }
 
  // Local function that returns true if its argument looks like a va_list.
  auto isVaList = [&S](QualType T) -> bool {
    auto *typedefTy = T->getAs<TypedefType>();
    if (!typedefTy)
      return false;
    TypedefDecl *vaListTypedef = S.Context.getBuiltinVaListDecl();
    do {
      if (typedefTy->getDecl() == vaListTypedef)
        return true;
      if (auto *name = typedefTy->getDecl()->getIdentifier())
        if (name->isStr("va_list"))
          return true;
      typedefTy = typedefTy->desugar()->getAs<TypedefType>();
    } while (typedefTy);
    return false;
  };
 
  // Local function that checks the nullability for a given pointer declarator.
  // Returns true if _Nonnull was inferred.
  auto inferPointerNullability =
      [&](SimplePointerKind pointerKind, SourceLocation pointerLoc,
          SourceLocation pointerEndLoc,
          ParsedAttributesView &attrs, AttributePool &Pool) -> ParsedAttr * {
    // We've seen a pointer.
    if (NumPointersRemaining > 0)
      --NumPointersRemaining;
 
    // If a nullability attribute is present, there's nothing to do.
    if (hasNullabilityAttr(attrs))
      return nullptr;
 
    // If we're supposed to infer nullability, do so now.
    if (inferNullability && !inferNullabilityInnerOnlyComplete) {
      ParsedAttr::Syntax syntax = inferNullabilityCS
                                      ? ParsedAttr::AS_ContextSensitiveKeyword
                                      : ParsedAttr::AS_Keyword;
      ParsedAttr *nullabilityAttr = Pool.create(
          S.getNullabilityKeyword(*inferNullability), SourceRange(pointerLoc),
          nullptr, SourceLocation(), nullptr, 0, syntax);
 
      attrs.addAtEnd(nullabilityAttr);
 
      if (inferNullabilityCS) {
        state.getDeclarator().getMutableDeclSpec().getObjCQualifiers()
          ->setObjCDeclQualifier(ObjCDeclSpec::DQ_CSNullability);
      }
 
      if (pointerLoc.isValid() &&
          complainAboutInferringWithinChunk !=
            PointerWrappingDeclaratorKind::None) {
        auto Diag =
            S.Diag(pointerLoc, diag::warn_nullability_inferred_on_nested_type);
        Diag << static_cast<int>(complainAboutInferringWithinChunk);
        fixItNullability(S, Diag, pointerLoc, NullabilityKind::NonNull);
      }
 
      if (inferNullabilityInnerOnly)
        inferNullabilityInnerOnlyComplete = true;
      return nullabilityAttr;
    }
 
    // If we're supposed to complain about missing nullability, do so
    // now if it's truly missing.
    switch (complainAboutMissingNullability) {
    case CAMN_No:
      break;
 
    case CAMN_InnerPointers:
      if (NumPointersRemaining == 0)
        break;
      [[fallthrough]];
 
    case CAMN_Yes:
      checkNullabilityConsistency(S, pointerKind, pointerLoc, pointerEndLoc);
    }
    return nullptr;
  };
 
  // If the type itself could have nullability but does not, infer pointer
  // nullability and perform consistency checking.
  if (S.CodeSynthesisContexts.empty()) {
    if (T->canHaveNullability(/*ResultIfUnknown*/ false) &&
        !T->getNullability()) {
      if (isVaList(T)) {
        // Record that we've seen a pointer, but do nothing else.
        if (NumPointersRemaining > 0)
          --NumPointersRemaining;
      } else {
        SimplePointerKind pointerKind = SimplePointerKind::Pointer;
        if (T->isBlockPointerType())
          pointerKind = SimplePointerKind::BlockPointer;
        else if (T->isMemberPointerType())
          pointerKind = SimplePointerKind::MemberPointer;
 
        if (auto *attr = inferPointerNullability(
                pointerKind, D.getDeclSpec().getTypeSpecTypeLoc(),
                D.getDeclSpec().getEndLoc(),
                D.getMutableDeclSpec().