text: //===-- DeclCXX.h - Classes for representing C++ declarations -*- C++ -*-=====//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  ///
  /// \file
  /// \brief Defines the C++ Decl subclasses, other than those for templates
  /// (found in DeclTemplate.h) and friends (in DeclFriend.h).
  ///
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_CLANG_AST_DECLCXX_H
  #define LLVM_CLANG_AST_DECLCXX_H
  
  #include "clang/AST/ASTContext.h"
  #include "clang/AST/ASTUnresolvedSet.h"
  #include "clang/AST/Attr.h"
  #include "clang/AST/Decl.h"
  #include "clang/AST/Expr.h"
  #include "clang/AST/LambdaCapture.h"
  #include "llvm/ADT/DenseMap.h"
  #include "llvm/ADT/PointerIntPair.h"
  #include "llvm/Support/Compiler.h"
  
  namespace clang {
  
  class ClassTemplateDecl;
  class ClassTemplateSpecializationDecl;
  class ConstructorUsingShadowDecl;
  class CXXBasePath;
  class CXXBasePaths;
  class CXXConstructorDecl;
  class CXXConversionDecl;
  class CXXDestructorDecl;
  class CXXMethodDecl;
  class CXXRecordDecl;
  class CXXMemberLookupCriteria;
  class CXXFinalOverriderMap;
  class CXXIndirectPrimaryBaseSet;
  class FriendDecl;
  class LambdaExpr;
  class UsingDecl;
  
  /// \brief Represents any kind of function declaration, whether it is a
  /// concrete function or a function template.
  class AnyFunctionDecl {
    NamedDecl *Function;
  
    AnyFunctionDecl(NamedDecl *ND) : Function(ND) { }
  
  public:
    AnyFunctionDecl(FunctionDecl *FD) : Function(FD) { }
    AnyFunctionDecl(FunctionTemplateDecl *FTD);
  
    /// \brief Implicily converts any function or function template into a
    /// named declaration.
    operator NamedDecl *() const { return Function; }
  
    /// \brief Retrieve the underlying function or function template.
    NamedDecl *get() const { return Function; }
  
    static AnyFunctionDecl getFromNamedDecl(NamedDecl *ND) {
      return AnyFunctionDecl(ND);
    }
  };
  
  } // end namespace clang
  
  namespace llvm {
    // Provide PointerLikeTypeTraits for non-cvr pointers.
    template<>
    class PointerLikeTypeTraits< ::clang::AnyFunctionDecl> {
    public:
      static inline void *getAsVoidPointer(::clang::AnyFunctionDecl F) {
        return F.get();
      }
      static inline ::clang::AnyFunctionDecl getFromVoidPointer(void *P) {
        return ::clang::AnyFunctionDecl::getFromNamedDecl(
                                        static_cast< ::clang::NamedDecl*>(P));
      }
  
      enum { NumLowBitsAvailable = 2 };
    };
  
  } // end namespace llvm
  
  namespace clang {
  
  /// \brief Represents an access specifier followed by colon ':'.
  ///
  /// An objects of this class represents sugar for the syntactic occurrence
  /// of an access specifier followed by a colon in the list of member
  /// specifiers of a C++ class definition.
  ///
  /// Note that they do not represent other uses of access specifiers,
  /// such as those occurring in a list of base specifiers.
  /// Also note that this class has nothing to do with so-called
  /// "access declarations" (C++98 11.3 [class.access.dcl]).
  class AccessSpecDecl : public Decl {
    virtual void anchor();
    /// \brief The location of the ':'.
    SourceLocation ColonLoc;
  
    AccessSpecDecl(AccessSpecifier AS, DeclContext *DC,
                   SourceLocation ASLoc, SourceLocation ColonLoc)
      : Decl(AccessSpec, DC, ASLoc), ColonLoc(ColonLoc) {
      setAccess(AS);
    }
    AccessSpecDecl(EmptyShell Empty)
      : Decl(AccessSpec, Empty) { }
  public:
    /// \brief The location of the access specifier.
    SourceLocation getAccessSpecifierLoc() const { return getLocation(); }
    /// \brief Sets the location of the access specifier.
    void setAccessSpecifierLoc(SourceLocation ASLoc) { setLocation(ASLoc); }
  
    /// \brief The location of the colon following the access specifier.
    SourceLocation getColonLoc() const { return ColonLoc; }
    /// \brief Sets the location of the colon.
    void setColonLoc(SourceLocation CLoc) { ColonLoc = CLoc; }
  
    SourceRange getSourceRange() const override LLVM_READONLY {
      return SourceRange(getAccessSpecifierLoc(), getColonLoc());
    }
  
    static AccessSpecDecl *Create(ASTContext &C, AccessSpecifier AS,
                                  DeclContext *DC, SourceLocation ASLoc,
                                  SourceLocation ColonLoc) {
      return new (C, DC) AccessSpecDecl(AS, DC, ASLoc, ColonLoc);
    }
    static AccessSpecDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    // Implement isa/cast/dyncast/etc.
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == AccessSpec; }
  };
  
  
  /// \brief Represents a base class of a C++ class.
  ///
  /// Each CXXBaseSpecifier represents a single, direct base class (or
  /// struct) of a C++ class (or struct). It specifies the type of that
  /// base class, whether it is a virtual or non-virtual base, and what
  /// level of access (public, protected, private) is used for the
  /// derivation. For example:
  ///
  /// \code
  ///   class A { };
  ///   class B { };
  ///   class C : public virtual A, protected B { };
  /// \endcode
  ///
  /// In this code, C will have two CXXBaseSpecifiers, one for "public
  /// virtual A" and the other for "protected B".
  class CXXBaseSpecifier {
    /// \brief The source code range that covers the full base
    /// specifier, including the "virtual" (if present) and access
    /// specifier (if present).
    SourceRange Range;
  
    /// \brief The source location of the ellipsis, if this is a pack
    /// expansion.
    SourceLocation EllipsisLoc;
  
    /// \brief Whether this is a virtual base class or not.
    unsigned Virtual : 1;
  
    /// \brief Whether this is the base of a class (true) or of a struct (false).
    ///
    /// This determines the mapping from the access specifier as written in the
    /// source code to the access specifier used for semantic analysis.
    unsigned BaseOfClass : 1;
  
    /// \brief Access specifier as written in the source code (may be AS_none).
    ///
    /// The actual type of data stored here is an AccessSpecifier, but we use
    /// "unsigned" here to work around a VC++ bug.
    unsigned Access : 2;
  
    /// \brief Whether the class contains a using declaration
    /// to inherit the named class's constructors.
    unsigned InheritConstructors : 1;
  
    /// \brief The type of the base class.
    ///
    /// This will be a class or struct (or a typedef of such). The source code
    /// range does not include the \c virtual or the access specifier.
    TypeSourceInfo *BaseTypeInfo;
  
  public:
    CXXBaseSpecifier() { }
  
    CXXBaseSpecifier(SourceRange R, bool V, bool BC, AccessSpecifier A,
                     TypeSourceInfo *TInfo, SourceLocation EllipsisLoc)
      : Range(R), EllipsisLoc(EllipsisLoc), Virtual(V), BaseOfClass(BC),
        Access(A), InheritConstructors(false), BaseTypeInfo(TInfo) { }
  
    /// \brief Retrieves the source range that contains the entire base specifier.
    SourceRange getSourceRange() const LLVM_READONLY { return Range; }
    SourceLocation getLocStart() const LLVM_READONLY { return Range.getBegin(); }
    SourceLocation getLocEnd() const LLVM_READONLY { return Range.getEnd(); }
  
    /// \brief Determines whether the base class is a virtual base class (or not).
    bool isVirtual() const { return Virtual; }
  
    /// \brief Determine whether this base class is a base of a class declared
    /// with the 'class' keyword (vs. one declared with the 'struct' keyword).
    bool isBaseOfClass() const { return BaseOfClass; }
  
    /// \brief Determine whether this base specifier is a pack expansion.
    bool isPackExpansion() const { return EllipsisLoc.isValid(); }
  
    /// \brief Determine whether this base class's constructors get inherited.
    bool getInheritConstructors() const { return InheritConstructors; }
  
    /// \brief Set that this base class's constructors should be inherited.
    void setInheritConstructors(bool Inherit = true) {
      InheritConstructors = Inherit;
    }
  
    /// \brief For a pack expansion, determine the location of the ellipsis.
    SourceLocation getEllipsisLoc() const {
      return EllipsisLoc;
    }
  
    /// \brief Returns the access specifier for this base specifier. 
    ///
    /// This is the actual base specifier as used for semantic analysis, so
    /// the result can never be AS_none. To retrieve the access specifier as
    /// written in the source code, use getAccessSpecifierAsWritten().
    AccessSpecifier getAccessSpecifier() const {
      if ((AccessSpecifier)Access == AS_none)
        return BaseOfClass? AS_private : AS_public;
      else
        return (AccessSpecifier)Access;
    }
  
    /// \brief Retrieves the access specifier as written in the source code
    /// (which may mean that no access specifier was explicitly written).
    ///
    /// Use getAccessSpecifier() to retrieve the access specifier for use in
    /// semantic analysis.
    AccessSpecifier getAccessSpecifierAsWritten() const {
      return (AccessSpecifier)Access;
    }
  
    /// \brief Retrieves the type of the base class.
    ///
    /// This type will always be an unqualified class type.
    QualType getType() const {
      return BaseTypeInfo->getType().getUnqualifiedType();
    }
  
    /// \brief Retrieves the type and source location of the base class.
    TypeSourceInfo *getTypeSourceInfo() const { return BaseTypeInfo; }
  };
  
  /// \brief Represents a C++ struct/union/class.
  class CXXRecordDecl : public RecordDecl {
  
    friend void TagDecl::startDefinition();
  
    /// Values used in DefinitionData fields to represent special members.
    enum SpecialMemberFlags {
      SMF_DefaultConstructor = 0x1,
      SMF_CopyConstructor = 0x2,
      SMF_MoveConstructor = 0x4,
      SMF_CopyAssignment = 0x8,
      SMF_MoveAssignment = 0x10,
      SMF_Destructor = 0x20,
      SMF_All = 0x3f
    };
  
    struct DefinitionData {
      DefinitionData(CXXRecordDecl *D);
  
      /// \brief True if this class has any user-declared constructors.
      unsigned UserDeclaredConstructor : 1;
  
      /// \brief The user-declared special members which this class has.
      unsigned UserDeclaredSpecialMembers : 6;
  
      /// \brief True when this class is an aggregate.
      unsigned Aggregate : 1;
  
      /// \brief True when this class is a POD-type.
      unsigned PlainOldData : 1;
  
      /// true when this class is empty for traits purposes,
      /// i.e. has no data members other than 0-width bit-fields, has no
      /// virtual function/base, and doesn't inherit from a non-empty
      /// class. Doesn't take union-ness into account.
      unsigned Empty : 1;
  
      /// \brief True when this class is polymorphic, i.e., has at
      /// least one virtual member or derives from a polymorphic class.
      unsigned Polymorphic : 1;
  
      /// \brief True when this class is abstract, i.e., has at least
      /// one pure virtual function, (that can come from a base class).
      unsigned Abstract : 1;
  
      /// \brief True when this class has standard layout.
      ///
      /// C++11 [class]p7.  A standard-layout class is a class that:
      /// * has no non-static data members of type non-standard-layout class (or
      ///   array of such types) or reference,
      /// * has no virtual functions (10.3) and no virtual base classes (10.1),
      /// * has the same access control (Clause 11) for all non-static data
      ///   members
      /// * has no non-standard-layout base classes,
      /// * either has no non-static data members in the most derived class and at
      ///   most one base class with non-static data members, or has no base
      ///   classes with non-static data members, and
      /// * has no base classes of the same type as the first non-static data
      ///   member.
      unsigned IsStandardLayout : 1;
  
      /// \brief True when there are no non-empty base classes.
      ///
      /// This is a helper bit of state used to implement IsStandardLayout more
      /// efficiently.
      unsigned HasNoNonEmptyBases : 1;
  
      /// \brief True when there are private non-static data members.
      unsigned HasPrivateFields : 1;
  
      /// \brief True when there are protected non-static data members.
      unsigned HasProtectedFields : 1;
  
      /// \brief True when there are private non-static data members.
      unsigned HasPublicFields : 1;
  
      /// \brief True if this class (or any subobject) has mutable fields.
      unsigned HasMutableFields : 1;
  
      /// \brief True if this class (or any nested anonymous struct or union)
      /// has variant members.
      unsigned HasVariantMembers : 1;
  
      /// \brief True if there no non-field members declared by the user.
      unsigned HasOnlyCMembers : 1;
  
      /// \brief True if any field has an in-class initializer, including those
      /// within anonymous unions or structs.
      unsigned HasInClassInitializer : 1;
  
      /// \brief True if any field is of reference type, and does not have an
      /// in-class initializer.
      ///
      /// In this case, value-initialization of this class is illegal in C++98
      /// even if the class has a trivial default constructor.
      unsigned HasUninitializedReferenceMember : 1;
  
      /// \brief True if any non-mutable field whose type doesn't have a user-
      /// provided default ctor also doesn't have an in-class initializer.
      unsigned HasUninitializedFields : 1;
  
      /// \brief True if there are any member using-declarations that inherit
      /// constructors from a base class.
      unsigned HasInheritedConstructor : 1;
  
      /// \brief True if there are any member using-declarations named
      /// 'operator='.
      unsigned HasInheritedAssignment : 1;
  
      /// \brief These flags are \c true if a defaulted corresponding special
      /// member can't be fully analyzed without performing overload resolution.
      /// @{
      unsigned NeedOverloadResolutionForMoveConstructor : 1;
      unsigned NeedOverloadResolutionForMoveAssignment : 1;
      unsigned NeedOverloadResolutionForDestructor : 1;
      /// @}
  
      /// \brief These flags are \c true if an implicit defaulted corresponding
      /// special member would be defined as deleted.
      /// @{
      unsigned DefaultedMoveConstructorIsDeleted : 1;
      unsigned DefaultedMoveAssignmentIsDeleted : 1;
      unsigned DefaultedDestructorIsDeleted : 1;
      /// @}
  
      /// \brief The trivial special members which this class has, per
      /// C++11 [class.ctor]p5, C++11 [class.copy]p12, C++11 [class.copy]p25,
      /// C++11 [class.dtor]p5, or would have if the member were not suppressed.
      ///
      /// This excludes any user-declared but not user-provided special members
      /// which have been declared but not yet defined.
      unsigned HasTrivialSpecialMembers : 6;
  
      /// \brief The declared special members of this class which are known to be
      /// non-trivial.
      ///
      /// This excludes any user-declared but not user-provided special members
      /// which have been declared but not yet defined, and any implicit special
      /// members which have not yet been declared.
      unsigned DeclaredNonTrivialSpecialMembers : 6;
  
      /// \brief True when this class has a destructor with no semantic effect.
      unsigned HasIrrelevantDestructor : 1;
  
      /// \brief True when this class has at least one user-declared constexpr
      /// constructor which is neither the copy nor move constructor.
      unsigned HasConstexprNonCopyMoveConstructor : 1;
  
      /// \brief True if this class has a (possibly implicit) defaulted default
      /// constructor.
      unsigned HasDefaultedDefaultConstructor : 1;
  
      /// \brief True if a defaulted default constructor for this class would
      /// be constexpr.
      unsigned DefaultedDefaultConstructorIsConstexpr : 1;
  
      /// \brief True if this class has a constexpr default constructor.
      ///
      /// This is true for either a user-declared constexpr default constructor
      /// or an implicitly declared constexpr default constructor.
      unsigned HasConstexprDefaultConstructor : 1;
  
      /// \brief True when this class contains at least one non-static data
      /// member or base class of non-literal or volatile type.
      unsigned HasNonLiteralTypeFieldsOrBases : 1;
  
      /// \brief True when visible conversion functions are already computed
      /// and are available.
      unsigned ComputedVisibleConversions : 1;
  
      /// \brief Whether we have a C++11 user-provided default constructor (not
      /// explicitly deleted or defaulted).
      unsigned UserProvidedDefaultConstructor : 1;
  
      /// \brief The special members which have been declared for this class,
      /// either by the user or implicitly.
      unsigned DeclaredSpecialMembers : 6;
  
      /// \brief Whether an implicit copy constructor would have a const-qualified
      /// parameter.
      unsigned ImplicitCopyConstructorHasConstParam : 1;
  
      /// \brief Whether an implicit copy assignment operator would have a
      /// const-qualified parameter.
      unsigned ImplicitCopyAssignmentHasConstParam : 1;
  
      /// \brief Whether any declared copy constructor has a const-qualified
      /// parameter.
      unsigned HasDeclaredCopyConstructorWithConstParam : 1;
  
      /// \brief Whether any declared copy assignment operator has either a
      /// const-qualified reference parameter or a non-reference parameter.
      unsigned HasDeclaredCopyAssignmentWithConstParam : 1;
  
      /// \brief Whether this class describes a C++ lambda.
      unsigned IsLambda : 1;
  
      /// \brief Whether we are currently parsing base specifiers.
      unsigned IsParsingBaseSpecifiers : 1;
  
      /// \brief The number of base class specifiers in Bases.
      unsigned NumBases;
  
      /// \brief The number of virtual base class specifiers in VBases.
      unsigned NumVBases;
  
      /// \brief Base classes of this class.
      ///
      /// FIXME: This is wasted space for a union.
      LazyCXXBaseSpecifiersPtr Bases;
  
      /// \brief direct and indirect virtual base classes of this class.
      LazyCXXBaseSpecifiersPtr VBases;
  
      /// \brief The conversion functions of this C++ class (but not its
      /// inherited conversion functions).
      ///
      /// Each of the entries in this overload set is a CXXConversionDecl.
      LazyASTUnresolvedSet Conversions;
  
      /// \brief The conversion functions of this C++ class and all those
      /// inherited conversion functions that are visible in this class.
      ///
      /// Each of the entries in this overload set is a CXXConversionDecl or a
      /// FunctionTemplateDecl.
      LazyASTUnresolvedSet VisibleConversions;
  
      /// \brief The declaration which defines this record.
      CXXRecordDecl *Definition;
  
      /// \brief The first friend declaration in this class, or null if there
      /// aren't any. 
      ///
      /// This is actually currently stored in reverse order.
      LazyDeclPtr FirstFriend;
  
      /// \brief Retrieve the set of direct base classes.
      CXXBaseSpecifier *getBases() const {
        if (!Bases.isOffset())
          return Bases.get(nullptr);
        return getBasesSlowCase();
      }
  
      /// \brief Retrieve the set of virtual base classes.
      CXXBaseSpecifier *getVBases() const {
        if (!VBases.isOffset())
          return VBases.get(nullptr);
        return getVBasesSlowCase();
      }
  
      ArrayRef<CXXBaseSpecifier> bases() const {
        return llvm::makeArrayRef(getBases(), NumBases);
      }
      ArrayRef<CXXBaseSpecifier> vbases() const {
        return llvm::makeArrayRef(getVBases(), NumVBases);
      }
  
    private:
      CXXBaseSpecifier *getBasesSlowCase() const;
      CXXBaseSpecifier *getVBasesSlowCase() const;
    };
  
    struct DefinitionData *DefinitionData;
  
    /// \brief Describes a C++ closure type (generated by a lambda expression).
    struct LambdaDefinitionData : public DefinitionData {
      typedef LambdaCapture Capture;
  
      LambdaDefinitionData(CXXRecordDecl *D, TypeSourceInfo *Info, 
                           bool Dependent, bool IsGeneric, 
                           LambdaCaptureDefault CaptureDefault) 
        : DefinitionData(D), Dependent(Dependent), IsGenericLambda(IsGeneric), 
          CaptureDefault(CaptureDefault), NumCaptures(0), NumExplicitCaptures(0), 
          ManglingNumber(0), ContextDecl(nullptr), Captures(nullptr),
          MethodTyInfo(Info) {
        IsLambda = true;
  
        // C++11 [expr.prim.lambda]p3:
        //   This class type is neither an aggregate nor a literal type.
        Aggregate = false;
        PlainOldData = false;
        HasNonLiteralTypeFieldsOrBases = true;
      }
  
      /// \brief Whether this lambda is known to be dependent, even if its
      /// context isn't dependent.
      /// 
      /// A lambda with a non-dependent context can be dependent if it occurs
      /// within the default argument of a function template, because the
      /// lambda will have been created with the enclosing context as its
      /// declaration context, rather than function. This is an unfortunate
      /// artifact of having to parse the default arguments before. 
      unsigned Dependent : 1;
      
      /// \brief Whether this lambda is a generic lambda.
      unsigned IsGenericLambda : 1;
  
      /// \brief The Default Capture.
      unsigned CaptureDefault : 2;
  
      /// \brief The number of captures in this lambda is limited 2^NumCaptures.
      unsigned NumCaptures : 15;
  
      /// \brief The number of explicit captures in this lambda.
      unsigned NumExplicitCaptures : 13;
  
      /// \brief The number used to indicate this lambda expression for name 
      /// mangling in the Itanium C++ ABI.
      unsigned ManglingNumber;
      
      /// \brief The declaration that provides context for this lambda, if the
      /// actual DeclContext does not suffice. This is used for lambdas that
      /// occur within default arguments of function parameters within the class
      /// or within a data member initializer.
      Decl *ContextDecl;
      
      /// \brief The list of captures, both explicit and implicit, for this 
      /// lambda.
      Capture *Captures;
  
      /// \brief The type of the call method.
      TypeSourceInfo *MethodTyInfo;
         
    };
  
    struct DefinitionData *dataPtr() const {
      // Complete the redecl chain (if necessary).
      getMostRecentDecl();
      return DefinitionData;
    }
  
    struct DefinitionData &data() const {
      auto *DD = dataPtr();
      assert(DD && "queried property of class with no definition");
      return *DD;
    }
  
    struct LambdaDefinitionData &getLambdaData() const {
      // No update required: a merged definition cannot change any lambda
      // properties.
      auto *DD = DefinitionData;
      assert(DD && DD->IsLambda && "queried lambda property of non-lambda class");
      return static_cast<LambdaDefinitionData&>(*DD);
    }
  
    /// \brief The template or declaration that this declaration
    /// describes or was instantiated from, respectively.
    ///
    /// For non-templates, this value will be null. For record
    /// declarations that describe a class template, this will be a
    /// pointer to a ClassTemplateDecl. For member
    /// classes of class template specializations, this will be the
    /// MemberSpecializationInfo referring to the member class that was
    /// instantiated or specialized.
    llvm::PointerUnion<ClassTemplateDecl*, MemberSpecializationInfo*>
      TemplateOrInstantiation;
  
    friend class DeclContext;
    friend class LambdaExpr;
  
    /// \brief Called from setBases and addedMember to notify the class that a
    /// direct or virtual base class or a member of class type has been added.
    void addedClassSubobject(CXXRecordDecl *Base);
  
    /// \brief Notify the class that member has been added.
    ///
    /// This routine helps maintain information about the class based on which
    /// members have been added. It will be invoked by DeclContext::addDecl()
    /// whenever a member is added to this record.
    void addedMember(Decl *D);
  
    void markedVirtualFunctionPure();
    friend void FunctionDecl::setPure(bool);
  
    friend class ASTNodeImporter;
  
    /// \brief Get the head of our list of friend declarations, possibly
    /// deserializing the friends from an external AST source.
    FriendDecl *getFirstFriend() const;
  
  protected:
    CXXRecordDecl(Kind K, TagKind TK, const ASTContext &C, DeclContext *DC,
                  SourceLocation StartLoc, SourceLocation IdLoc,
                  IdentifierInfo *Id, CXXRecordDecl *PrevDecl);
  
  public:
    /// \brief Iterator that traverses the base classes of a class.
    typedef CXXBaseSpecifier*       base_class_iterator;
  
    /// \brief Iterator that traverses the base classes of a class.
    typedef const CXXBaseSpecifier* base_class_const_iterator;
  
    CXXRecordDecl *getCanonicalDecl() override {
      return cast<CXXRecordDecl>(RecordDecl::getCanonicalDecl());
    }
    const CXXRecordDecl *getCanonicalDecl() const {
      return const_cast<CXXRecordDecl*>(this)->getCanonicalDecl();
    }
  
    CXXRecordDecl *getPreviousDecl() {
      return cast_or_null<CXXRecordDecl>(
              static_cast<RecordDecl *>(this)->getPreviousDecl());
    }
    const CXXRecordDecl *getPreviousDecl() const {
      return const_cast<CXXRecordDecl*>(this)->getPreviousDecl();
    }
  
    CXXRecordDecl *getMostRecentDecl() {
      return cast<CXXRecordDecl>(
              static_cast<RecordDecl *>(this)->getMostRecentDecl());
    }
  
    const CXXRecordDecl *getMostRecentDecl() const {
      return const_cast<CXXRecordDecl*>(this)->getMostRecentDecl();
    }
  
    CXXRecordDecl *getDefinition() const {
      // We only need an update if we don't already know which
      // declaration is the definition.
      auto *DD = DefinitionData ? DefinitionData : dataPtr();
      return DD ? DD->Definition : nullptr;
    }
  
    bool hasDefinition() const { return DefinitionData || dataPtr(); }
  
    static CXXRecordDecl *Create(const ASTContext &C, TagKind TK, DeclContext *DC,
                                 SourceLocation StartLoc, SourceLocation IdLoc,
                                 IdentifierInfo *Id,
                                 CXXRecordDecl *PrevDecl = nullptr,
                                 bool DelayTypeCreation = false);
    static CXXRecordDecl *CreateLambda(const ASTContext &C, DeclContext *DC,
                                       TypeSourceInfo *Info, SourceLocation Loc,
                                       bool DependentLambda, bool IsGeneric,
                                       LambdaCaptureDefault CaptureDefault);
    static CXXRecordDecl *CreateDeserialized(const ASTContext &C, unsigned ID);
  
    bool isDynamicClass() const {
      return data().Polymorphic || data().NumVBases != 0;
    }
  
    void setIsParsingBaseSpecifiers() { data().IsParsingBaseSpecifiers = true; }
  
    bool isParsingBaseSpecifiers() const {
      return data().IsParsingBaseSpecifiers;
    }
  
    /// \brief Sets the base classes of this struct or class.
    void setBases(CXXBaseSpecifier const * const *Bases, unsigned NumBases);
  
    /// \brief Retrieves the number of base classes of this class.
    unsigned getNumBases() const { return data().NumBases; }
  
    typedef llvm::iterator_range<base_class_iterator> base_class_range;
    typedef llvm::iterator_range<base_class_const_iterator>
      base_class_const_range;
  
    base_class_range bases() {
      return base_class_range(bases_begin(), bases_end());
    }
    base_class_const_range bases() const {
      return base_class_const_range(bases_begin(), bases_end());
    }
  
    base_class_iterator bases_begin() { return data().getBases(); }
    base_class_const_iterator bases_begin() const { return data().getBases(); }
    base_class_iterator bases_end() { return bases_begin() + data().NumBases; }
    base_class_const_iterator bases_end() const {
      return bases_begin() + data().NumBases;
    }
  
    /// \brief Retrieves the number of virtual base classes of this class.
    unsigned getNumVBases() const { return data().NumVBases; }
  
    base_class_range vbases() {
      return base_class_range(vbases_begin(), vbases_end());
    }
    base_class_const_range vbases() const {
      return base_class_const_range(vbases_begin(), vbases_end());
    }
  
    base_class_iterator vbases_begin() { return data().getVBases(); }
    base_class_const_iterator vbases_begin() const { return data().getVBases(); }
    base_class_iterator vbases_end() { return vbases_begin() + data().NumVBases; }
    base_class_const_iterator vbases_end() const {
      return vbases_begin() + data().NumVBases;
    }
  
    /// \brief Determine whether this class has any dependent base classes which
    /// are not the current instantiation.
    bool hasAnyDependentBases() const;
  
    /// Iterator access to method members.  The method iterator visits
    /// all method members of the class, including non-instance methods,
    /// special methods, etc.
    typedef specific_decl_iterator<CXXMethodDecl> method_iterator;
    typedef llvm::iterator_range<specific_decl_iterator<CXXMethodDecl>>
      method_range;
  
    method_range methods() const {
      return method_range(method_begin(), method_end());
    }
  
    /// \brief Method begin iterator.  Iterates in the order the methods
    /// were declared.
    method_iterator method_begin() const {
      return method_iterator(decls_begin());
    }
    /// \brief Method past-the-end iterator.
    method_iterator method_end() const {
      return method_iterator(decls_end());
    }
  
    /// Iterator access to constructor members.
    typedef specific_decl_iterator<CXXConstructorDecl> ctor_iterator;
    typedef llvm::iterator_range<specific_decl_iterator<CXXConstructorDecl>>
      ctor_range;
  
    ctor_range ctors() const { return ctor_range(ctor_begin(), ctor_end()); }
  
    ctor_iterator ctor_begin() const {
      return ctor_iterator(decls_begin());
    }
    ctor_iterator ctor_end() const {
      return ctor_iterator(decls_end());
    }
  
    /// An iterator over friend declarations.  All of these are defined
    /// in DeclFriend.h.
    class friend_iterator;
    typedef llvm::iterator_range<friend_iterator> friend_range;
  
    friend_range friends() const;
    friend_iterator friend_begin() const;
    friend_iterator friend_end() const;
    void pushFriendDecl(FriendDecl *FD);
  
    /// Determines whether this record has any friends.
    bool hasFriends() const {
      return data().FirstFriend.isValid();
    }
  
    /// \brief \c true if we know for sure that this class has a single,
    /// accessible, unambiguous move constructor that is not deleted.
    bool hasSimpleMoveConstructor() const {
      return !hasUserDeclaredMoveConstructor() && hasMoveConstructor() &&
             !data().DefaultedMoveConstructorIsDeleted;
    }
    /// \brief \c true if we know for sure that this class has a single,
    /// accessible, unambiguous move assignment operator that is not deleted.
    bool hasSimpleMoveAssignment() const {
      return !hasUserDeclaredMoveAssignment() && hasMoveAssignment() &&
             !data().DefaultedMoveAssignmentIsDeleted;
    }
    /// \brief \c true if we know for sure that this class has an accessible
    /// destructor that is not deleted.
    bool hasSimpleDestructor() const {
      return !hasUserDeclaredDestructor() &&
             !data().DefaultedDestructorIsDeleted;
    }
  
    /// \brief Determine whether this class has any default constructors.
    bool hasDefaultConstructor() const {
      return (data().DeclaredSpecialMembers & SMF_DefaultConstructor) ||
             needsImplicitDefaultConstructor();
    }
  
    /// \brief Determine if we need to declare a default constructor for
    /// this class.
    ///
    /// This value is used for lazy creation of default constructors.
    bool needsImplicitDefaultConstructor() const {
      return !data().UserDeclaredConstructor &&
             !(data().DeclaredSpecialMembers & SMF_DefaultConstructor) &&
             // C++14 [expr.prim.lambda]p20:
             //   The closure type associated with a lambda-expression has no
             //   default constructor.
             !isLambda();
    }
  
    /// \brief Determine whether this class has any user-declared constructors.
    ///
    /// When true, a default constructor will not be implicitly declared.
    bool hasUserDeclaredConstructor() const {
      return data().UserDeclaredConstructor;
    }
  
    /// \brief Whether this class has a user-provided default constructor
    /// per C++11.
    bool hasUserProvidedDefaultConstructor() const {
      return data().UserProvidedDefaultConstructor;
    }
  
    /// \brief Determine whether this class has a user-declared copy constructor.
    ///
    /// When false, a copy constructor will be implicitly declared.
    bool hasUserDeclaredCopyConstructor() const {
      return data().UserDeclaredSpecialMembers & SMF_CopyConstructor;
    }
  
    /// \brief Determine whether this class needs an implicit copy
    /// constructor to be lazily declared.
    bool needsImplicitCopyConstructor() const {
      return !(data().DeclaredSpecialMembers & SMF_CopyConstructor);
    }
  
    /// \brief Determine whether we need to eagerly declare a defaulted copy
    /// constructor for this class.
    bool needsOverloadResolutionForCopyConstructor() const {
      return data().HasMutableFields;
    }
  
    /// \brief Determine whether an implicit copy constructor for this type
    /// would have a parameter with a const-qualified reference type.
    bool implicitCopyConstructorHasConstParam() const {
      return data().ImplicitCopyConstructorHasConstParam;
    }
  
    /// \brief Determine whether this class has a copy constructor with
    /// a parameter type which is a reference to a const-qualified type.
    bool hasCopyConstructorWithConstParam() const {
      return data().HasDeclaredCopyConstructorWithConstParam ||
             (needsImplicitCopyConstructor() &&
              implicitCopyConstructorHasConstParam());
    }
  
    /// \brief Whether this class has a user-declared move constructor or
    /// assignment operator.
    ///
    /// When false, a move constructor and assignment operator may be
    /// implicitly declared.
    bool hasUserDeclaredMoveOperation() const {
      return data().UserDeclaredSpecialMembers &
               (SMF_MoveConstructor | SMF_MoveAssignment);
    }
  
    /// \brief Determine whether this class has had a move constructor
    /// declared by the user.
    bool hasUserDeclaredMoveConstructor() const {
      return data().UserDeclaredSpecialMembers & SMF_MoveConstructor;
    }
  
    /// \brief Determine whether this class has a move constructor.
    bool hasMoveConstructor() const {
      return (data().DeclaredSpecialMembers & SMF_MoveConstructor) ||
             needsImplicitMoveConstructor();
    }
  
    /// \brief Set that we attempted to declare an implicitly move
    /// constructor, but overload resolution failed so we deleted it.
    void setImplicitMoveConstructorIsDeleted() {
      assert((data().DefaultedMoveConstructorIsDeleted ||
              needsOverloadResolutionForMoveConstructor()) &&
             "move constructor should not be deleted");
      data().DefaultedMoveConstructorIsDeleted = true;
    }
  
    /// \brief Determine whether this class should get an implicit move
    /// constructor or if any existing special member function inhibits this.
    bool needsImplicitMoveConstructor() const {
      return !(data().DeclaredSpecialMembers & SMF_MoveConstructor) &&
             !hasUserDeclaredCopyConstructor() &&
             !hasUserDeclaredCopyAssignment() &&
             !hasUserDeclaredMoveAssignment() &&
             !hasUserDeclaredDestructor();
    }
  
    /// \brief Determine whether we need to eagerly declare a defaulted move
    /// constructor for this class.
    bool needsOverloadResolutionForMoveConstructor() const {
      return data().NeedOverloadResolutionForMoveConstructor;
    }
  
    /// \brief Determine whether this class has a user-declared copy assignment
    /// operator.
    ///
    /// When false, a copy assigment operator will be implicitly declared.
    bool hasUserDeclaredCopyAssignment() const {
      return data().UserDeclaredSpecialMembers & SMF_CopyAssignment;
    }
  
    /// \brief Determine whether this class needs an implicit copy
    /// assignment operator to be lazily declared.
    bool needsImplicitCopyAssignment() const {
      return !(data().DeclaredSpecialMembers & SMF_CopyAssignment);
    }
  
    /// \brief Determine whether we need to eagerly declare a defaulted copy
    /// assignment operator for this class.
    bool needsOverloadResolutionForCopyAssignment() const {
      return data().HasMutableFields;
    }
  
    /// \brief Determine whether an implicit copy assignment operator for this
    /// type would have a parameter with a const-qualified reference type.
    bool implicitCopyAssignmentHasConstParam() const {
      return data().ImplicitCopyAssignmentHasConstParam;
    }
  
    /// \brief Determine whether this class has a copy assignment operator with
    /// a parameter type which is a reference to a const-qualified type or is not
    /// a reference.
    bool hasCopyAssignmentWithConstParam() const {
      return data().HasDeclaredCopyAssignmentWithConstParam ||
             (needsImplicitCopyAssignment() &&
              implicitCopyAssignmentHasConstParam());
    }
  
    /// \brief Determine whether this class has had a move assignment
    /// declared by the user.
    bool hasUserDeclaredMoveAssignment() const {
      return data().UserDeclaredSpecialMembers & SMF_MoveAssignment;
    }
  
    /// \brief Determine whether this class has a move assignment operator.
    bool hasMoveAssignment() const {
      return (data().DeclaredSpecialMembers & SMF_MoveAssignment) ||
             needsImplicitMoveAssignment();
    }
  
    /// \brief Set that we attempted to declare an implicit move assignment
    /// operator, but overload resolution failed so we deleted it.
    void setImplicitMoveAssignmentIsDeleted() {
      assert((data().DefaultedMoveAssignmentIsDeleted ||
              needsOverloadResolutionForMoveAssignment()) &&
             "move assignment should not be deleted");
      data().DefaultedMoveAssignmentIsDeleted = true;
    }
  
    /// \brief Determine whether this class should get an implicit move
    /// assignment operator or if any existing special member function inhibits
    /// this.
    bool needsImplicitMoveAssignment() const {
      return !(data().DeclaredSpecialMembers & SMF_MoveAssignment) &&
             !hasUserDeclaredCopyConstructor() &&
             !hasUserDeclaredCopyAssignment() &&
             !hasUserDeclaredMoveConstructor() &&
             !hasUserDeclaredDestructor();
    }
  
    /// \brief Determine whether we need to eagerly declare a move assignment
    /// operator for this class.
    bool needsOverloadResolutionForMoveAssignment() const {
      return data().NeedOverloadResolutionForMoveAssignment;
    }
  
    /// \brief Determine whether this class has a user-declared destructor.
    ///
    /// When false, a destructor will be implicitly declared.
    bool hasUserDeclaredDestructor() const {
      return data().UserDeclaredSpecialMembers & SMF_Destructor;
    }
  
    /// \brief Determine whether this class needs an implicit destructor to
    /// be lazily declared.
    bool needsImplicitDestructor() const {
      return !(data().DeclaredSpecialMembers & SMF_Destructor);
    }
  
    /// \brief Determine whether we need to eagerly declare a destructor for this
    /// class.
    bool needsOverloadResolutionForDestructor() const {
      return data().NeedOverloadResolutionForDestructor;
    }
  
    /// \brief Determine whether this class describes a lambda function object.
    bool isLambda() const {
      // An update record can't turn a non-lambda into a lambda.
      auto *DD = DefinitionData;
      return DD && DD->IsLambda;
    }
  
    /// \brief Determine whether this class describes a generic 
    /// lambda function object (i.e. function call operator is
    /// a template). 
    bool isGenericLambda() const; 
  
    /// \brief Retrieve the lambda call operator of the closure type
    /// if this is a closure type.
    CXXMethodDecl *getLambdaCallOperator() const; 
  
    /// \brief Retrieve the lambda static invoker, the address of which
    /// is returned by the conversion operator, and the body of which
    /// is forwarded to the lambda call operator. 
    CXXMethodDecl *getLambdaStaticInvoker() const; 
  
    /// \brief Retrieve the generic lambda's template parameter list.
    /// Returns null if the class does not represent a lambda or a generic 
    /// lambda.
    TemplateParameterList *getGenericLambdaTemplateParameterList() const;
  
    LambdaCaptureDefault getLambdaCaptureDefault() const {
      assert(isLambda());
      return static_cast<LambdaCaptureDefault>(getLambdaData().CaptureDefault);
    }
  
    /// \brief For a closure type, retrieve the mapping from captured
    /// variables and \c this to the non-static data members that store the
    /// values or references of the captures.
    ///
    /// \param Captures Will be populated with the mapping from captured
    /// variables to the corresponding fields.
    ///
    /// \param ThisCapture Will be set to the field declaration for the
    /// \c this capture.
    ///
    /// \note No entries will be added for init-captures, as they do not capture
    /// variables.
    void getCaptureFields(llvm::DenseMap<const VarDecl *, FieldDecl *> &Captures,
                          FieldDecl *&ThisCapture) const;
  
    typedef const LambdaCapture *capture_const_iterator;
    typedef llvm::iterator_range<capture_const_iterator> capture_const_range;
  
    capture_const_range captures() const {
      return capture_const_range(captures_begin(), captures_end());
    }
    capture_const_iterator captures_begin() const {
      return isLambda() ? getLambdaData().Captures : nullptr;
    }
    capture_const_iterator captures_end() const {
      return isLambda() ? captures_begin() + getLambdaData().NumCaptures
                        : nullptr;
    }
  
    typedef UnresolvedSetIterator conversion_iterator;
    conversion_iterator conversion_begin() const {
      return data().Conversions.get(getASTContext()).begin();
    }
    conversion_iterator conversion_end() const {
      return data().Conversions.get(getASTContext()).end();
    }
  
    /// Removes a conversion function from this class.  The conversion
    /// function must currently be a member of this class.  Furthermore,
    /// this class must currently be in the process of being defined.
    void removeConversion(const NamedDecl *Old);
  
    /// \brief Get all conversion functions visible in current class,
    /// including conversion function templates.
    llvm::iterator_range<conversion_iterator> getVisibleConversionFunctions();
  
    /// Determine whether this class is an aggregate (C++ [dcl.init.aggr]),
    /// which is a class with no user-declared constructors, no private
    /// or protected non-static data members, no base classes, and no virtual
    /// functions (C++ [dcl.init.aggr]p1).
    bool isAggregate() const { return data().Aggregate; }
  
    /// \brief Whether this class has any in-class initializers
    /// for non-static data members (including those in anonymous unions or
    /// structs).
    bool hasInClassInitializer() const { return data().HasInClassInitializer; }
  
    /// \brief Whether this class or any of its subobjects has any members of
    /// reference type which would make value-initialization ill-formed.
    ///
    /// Per C++03 [dcl.init]p5:
    ///  - if T is a non-union class type without a user-declared constructor,
    ///    then every non-static data member and base-class component of T is
    ///    value-initialized [...] A program that calls for [...]
    ///    value-initialization of an entity of reference type is ill-formed.
    bool hasUninitializedReferenceMember() const {
      return !isUnion() && !hasUserDeclaredConstructor() &&
             data().HasUninitializedReferenceMember;
    }
  
    /// \brief Whether this class is a POD-type (C++ [class]p4)
    ///
    /// For purposes of this function a class is POD if it is an aggregate
    /// that has no non-static non-POD data members, no reference data
    /// members, no user-defined copy assignment operator and no
    /// user-defined destructor.
    ///
    /// Note that this is the C++ TR1 definition of POD.
    bool isPOD() const { return data().PlainOldData; }
  
    /// \brief True if this class is C-like, without C++-specific features, e.g.
    /// it contains only public fields, no bases, tag kind is not 'class', etc.
    bool isCLike() const;
  
    /// \brief Determine whether this is an empty class in the sense of
    /// (C++11 [meta.unary.prop]).
    ///
    /// The CXXRecordDecl is a class type, but not a union type,
    /// with no non-static data members other than bit-fields of length 0,
    /// no virtual member functions, no virtual base classes,
    /// and no base class B for which is_empty<B>::value is false.
    ///
    /// \note This does NOT include a check for union-ness.
    bool isEmpty() const { return data().Empty; }
  
    /// Whether this class is polymorphic (C++ [class.virtual]),
    /// which means that the class contains or inherits a virtual function.
    bool isPolymorphic() const { return data().Polymorphic; }
  
    /// \brief Determine whether this class has a pure virtual function.
    ///
    /// The class is is abstract per (C++ [class.abstract]p2) if it declares
    /// a pure virtual function or inherits a pure virtual function that is
    /// not overridden.
    bool isAbstract() const { return data().Abstract; }
  
    /// \brief Determine whether this class has standard layout per 
    /// (C++ [class]p7)
    bool isStandardLayout() const { return data().IsStandardLayout; }
  
    /// \brief Determine whether this class, or any of its class subobjects,
    /// contains a mutable field.
    bool hasMutableFields() const { return data().HasMutableFields; }
  
    /// \brief Determine whether this class has any variant members.
    bool hasVariantMembers() const { return data().HasVariantMembers; }
  
    /// \brief Determine whether this class has a trivial default constructor
    /// (C++11 [class.ctor]p5).
    bool hasTrivialDefaultConstructor() const {
      return hasDefaultConstructor() &&
             (data().HasTrivialSpecialMembers & SMF_DefaultConstructor);
    }
  
    /// \brief Determine whether this class has a non-trivial default constructor
    /// (C++11 [class.ctor]p5).
    bool hasNonTrivialDefaultConstructor() const {
      return (data().DeclaredNonTrivialSpecialMembers & SMF_DefaultConstructor) ||
             (needsImplicitDefaultConstructor() &&
              !(data().HasTrivialSpecialMembers & SMF_DefaultConstructor));
    }
  
    /// \brief Determine whether this class has at least one constexpr constructor
    /// other than the copy or move constructors.
    bool hasConstexprNonCopyMoveConstructor() const {
      return data().HasConstexprNonCopyMoveConstructor ||
             (needsImplicitDefaultConstructor() &&
              defaultedDefaultConstructorIsConstexpr());
    }
  
    /// \brief Determine whether a defaulted default constructor for this class
    /// would be constexpr.
    bool defaultedDefaultConstructorIsConstexpr() const {
      return data().DefaultedDefaultConstructorIsConstexpr &&
             (!isUnion() || hasInClassInitializer() || !hasVariantMembers());
    }
  
    /// \brief Determine whether this class has a constexpr default constructor.
    bool hasConstexprDefaultConstructor() const {
      return data().HasConstexprDefaultConstructor ||
             (needsImplicitDefaultConstructor() &&
              defaultedDefaultConstructorIsConstexpr());
    }
  
    /// \brief Determine whether this class has a trivial copy constructor
    /// (C++ [class.copy]p6, C++11 [class.copy]p12)
    bool hasTrivialCopyConstructor() const {
      return data().HasTrivialSpecialMembers & SMF_CopyConstructor;
    }
  
    /// \brief Determine whether this class has a non-trivial copy constructor
    /// (C++ [class.copy]p6, C++11 [class.copy]p12)
    bool hasNonTrivialCopyConstructor() const {
      return data().DeclaredNonTrivialSpecialMembers & SMF_CopyConstructor ||
             !hasTrivialCopyConstructor();
    }
  
    /// \brief Determine whether this class has a trivial move constructor
    /// (C++11 [class.copy]p12)
    bool hasTrivialMoveConstructor() const {
      return hasMoveConstructor() &&
             (data().HasTrivialSpecialMembers & SMF_MoveConstructor);
    }
  
    /// \brief Determine whether this class has a non-trivial move constructor
    /// (C++11 [class.copy]p12)
    bool hasNonTrivialMoveConstructor() const {
      return (data().DeclaredNonTrivialSpecialMembers & SMF_MoveConstructor) ||
             (needsImplicitMoveConstructor() &&
              !(data().HasTrivialSpecialMembers & SMF_MoveConstructor));
    }
  
    /// \brief Determine whether this class has a trivial copy assignment operator
    /// (C++ [class.copy]p11, C++11 [class.copy]p25)
    bool hasTrivialCopyAssignment() const {
      return data().HasTrivialSpecialMembers & SMF_CopyAssignment;
    }
  
    /// \brief Determine whether this class has a non-trivial copy assignment
    /// operator (C++ [class.copy]p11, C++11 [class.copy]p25)
    bool hasNonTrivialCopyAssignment() const {
      return data().DeclaredNonTrivialSpecialMembers & SMF_CopyAssignment ||
             !hasTrivialCopyAssignment();
    }
  
    /// \brief Determine whether this class has a trivial move assignment operator
    /// (C++11 [class.copy]p25)
    bool hasTrivialMoveAssignment() const {
      return hasMoveAssignment() &&
             (data().HasTrivialSpecialMembers & SMF_MoveAssignment);
    }
  
    /// \brief Determine whether this class has a non-trivial move assignment
    /// operator (C++11 [class.copy]p25)
    bool hasNonTrivialMoveAssignment() const {
      return (data().DeclaredNonTrivialSpecialMembers & SMF_MoveAssignment) ||
             (needsImplicitMoveAssignment() &&
              !(data().HasTrivialSpecialMembers & SMF_MoveAssignment));
    }
  
    /// \brief Determine whether this class has a trivial destructor
    /// (C++ [class.dtor]p3)
    bool hasTrivialDestructor() const {
      return data().HasTrivialSpecialMembers & SMF_Destructor;
    }
  
    /// \brief Determine whether this class has a non-trivial destructor
    /// (C++ [class.dtor]p3)
    bool hasNonTrivialDestructor() const {
      return !(data().HasTrivialSpecialMembers & SMF_Destructor);
    }
  
    /// \brief Determine whether declaring a const variable with this type is ok
    /// per core issue 253.
    bool allowConstDefaultInit() const {
      return !data().HasUninitializedFields ||
             !(data().HasDefaultedDefaultConstructor ||
               needsImplicitDefaultConstructor());
    }
  
    /// \brief Determine whether this class has a destructor which has no
    /// semantic effect.
    ///
    /// Any such destructor will be trivial, public, defaulted and not deleted,
    /// and will call only irrelevant destructors.
    bool hasIrrelevantDestructor() const {
      return data().HasIrrelevantDestructor;
    }
  
    /// \brief Determine whether this class has a non-literal or/ volatile type
    /// non-static data member or base class.
    bool hasNonLiteralTypeFieldsOrBases() const {
      return data().HasNonLiteralTypeFieldsOrBases;
    }
  
    /// \brief Determine whether this class has a using-declaration that names
    /// a user-declared base class constructor.
    bool hasInheritedConstructor() const {
      return data().HasInheritedConstructor;
    }
  
    /// \brief Determine whether this class has a using-declaration that names
    /// a base class assignment operator.
    bool hasInheritedAssignment() const {
      return data().HasInheritedAssignment;
    }
  
    /// \brief Determine whether this class is considered trivially copyable per
    /// (C++11 [class]p6).
    bool isTriviallyCopyable() const;
  
    /// \brief Determine whether this class is considered trivial.
    ///
    /// C++11 [class]p6:
    ///    "A trivial class is a class that has a trivial default constructor and
    ///    is trivially copiable."
    bool isTrivial() const {
      return isTriviallyCopyable() && hasTrivialDefaultConstructor();
    }
  
    /// \brief Determine whether this class is a literal type.
    ///
    /// C++11 [basic.types]p10:
    ///   A class type that has all the following properties:
    ///     - it has a trivial destructor
    ///     - every constructor call and full-expression in the
    ///       brace-or-equal-intializers for non-static data members (if any) is
    ///       a constant expression.
    ///     - it is an aggregate type or has at least one constexpr constructor
    ///       or constructor template that is not a copy or move constructor, and
    ///     - all of its non-static data members and base classes are of literal
    ///       types
    ///
    /// We resolve DR1361 by ignoring the second bullet. We resolve DR1452 by
    /// treating types with trivial default constructors as literal types.
    bool isLiteral() const {
      return hasTrivialDestructor() &&
             (isAggregate() || hasConstexprNonCopyMoveConstructor() ||
              hasTrivialDefaultConstructor()) &&
             !hasNonLiteralTypeFieldsOrBases();
    }
  
    /// \brief If this record is an instantiation of a member class,
    /// retrieves the member class from which it was instantiated.
    ///
    /// This routine will return non-null for (non-templated) member
    /// classes of class templates. For example, given:
    ///
    /// \code
    /// template<typename T>
    /// struct X {
    ///   struct A { };
    /// };
    /// \endcode
    ///
    /// The declaration for X<int>::A is a (non-templated) CXXRecordDecl
    /// whose parent is the class template specialization X<int>. For
    /// this declaration, getInstantiatedFromMemberClass() will return
    /// the CXXRecordDecl X<T>::A. When a complete definition of
    /// X<int>::A is required, it will be instantiated from the
    /// declaration returned by getInstantiatedFromMemberClass().
    CXXRecordDecl *getInstantiatedFromMemberClass() const;
  
    /// \brief If this class is an instantiation of a member class of a
    /// class template specialization, retrieves the member specialization
    /// information.
    MemberSpecializationInfo *getMemberSpecializationInfo() const;
  
    /// \brief Specify that this record is an instantiation of the
    /// member class \p RD.
    void setInstantiationOfMemberClass(CXXRecordDecl *RD,
                                       TemplateSpecializationKind TSK);
  
    /// \brief Retrieves the class template that is described by this
    /// class declaration.
    ///
    /// Every class template is represented as a ClassTemplateDecl and a
    /// CXXRecordDecl. The former contains template properties (such as
    /// the template parameter lists) while the latter contains the
    /// actual description of the template's
    /// contents. ClassTemplateDecl::getTemplatedDecl() retrieves the
    /// CXXRecordDecl that from a ClassTemplateDecl, while
    /// getDescribedClassTemplate() retrieves the ClassTemplateDecl from
    /// a CXXRecordDecl.
    ClassTemplateDecl *getDescribedClassTemplate() const;
  
    void setDescribedClassTemplate(ClassTemplateDecl *Template);
  
    /// \brief Determine whether this particular class is a specialization or
    /// instantiation of a class template or member class of a class template,
    /// and how it was instantiated or specialized.
    TemplateSpecializationKind getTemplateSpecializationKind() const;
  
    /// \brief Set the kind of specialization or template instantiation this is.
    void setTemplateSpecializationKind(TemplateSpecializationKind TSK);
  
    /// \brief Retrieve the record declaration from which this record could be
    /// instantiated. Returns null if this class is not a template instantiation.
    const CXXRecordDecl *getTemplateInstantiationPattern() const;
  
    CXXRecordDecl *getTemplateInstantiationPattern() {
      return const_cast<CXXRecordDecl *>(const_cast<const CXXRecordDecl *>(this)
                                             ->getTemplateInstantiationPattern());
    }
  
    /// \brief Returns the destructor decl for this class.
    CXXDestructorDecl *getDestructor() const;
  
    /// \brief Returns true if the class destructor, or any implicitly invoked
    /// destructors are marked noreturn.
    bool isAnyDestructorNoReturn() const;
  
    /// \brief If the class is a local class [class.local], returns
    /// the enclosing function declaration.
    const FunctionDecl *isLocalClass() const {
      if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(getDeclContext()))
        return RD->isLocalClass();
  
      return dyn_cast<FunctionDecl>(getDeclContext());
    }
  
    FunctionDecl *isLocalClass() {
      return const_cast<FunctionDecl*>(
          const_cast<const CXXRecordDecl*>(this)->isLocalClass());
    }
  
    /// \brief Determine whether this dependent class is a current instantiation,
    /// when viewed from within the given context.
    bool isCurrentInstantiation(const DeclContext *CurContext) const;
  
    /// \brief Determine whether this class is derived from the class \p Base.
    ///
    /// This routine only determines whether this class is derived from \p Base,
    /// but does not account for factors that may make a Derived -> Base class
    /// ill-formed, such as private/protected inheritance or multiple, ambiguous
    /// base class subobjects.
    ///
    /// \param Base the base class we are searching for.
    ///
    /// \returns true if this class is derived from Base, false otherwise.
    bool isDerivedFrom(const CXXRecordDecl *Base) const;
  
    /// \brief Determine whether this class is derived from the type \p Base.
    ///
    /// This routine only determines whether this class is derived from \p Base,
    /// but does not account for factors that may make a Derived -> Base class
    /// ill-formed, such as private/protected inheritance or multiple, ambiguous
    /// base class subobjects.
    ///
    /// \param Base the base class we are searching for.
    ///
    /// \param Paths will contain the paths taken from the current class to the
    /// given \p Base class.
    ///
    /// \returns true if this class is derived from \p Base, false otherwise.
    ///
    /// \todo add a separate parameter to configure IsDerivedFrom, rather than
    /// tangling input and output in \p Paths
    bool isDerivedFrom(const CXXRecordDecl *Base, CXXBasePaths &Paths) const;
  
    /// \brief Determine whether this class is virtually derived from
    /// the class \p Base.
    ///
    /// This routine only determines whether this class is virtually
    /// derived from \p Base, but does not account for factors that may
    /// make a Derived -> Base class ill-formed, such as
    /// private/protected inheritance or multiple, ambiguous base class
    /// subobjects.
    ///
    /// \param Base the base class we are searching for.
    ///
    /// \returns true if this class is virtually derived from Base,
    /// false otherwise.
    bool isVirtuallyDerivedFrom(const CXXRecordDecl *Base) const;
  
    /// \brief Determine whether this class is provably not derived from
    /// the type \p Base.
    bool isProvablyNotDerivedFrom(const CXXRecordDecl *Base) const;
  
    /// \brief Function type used by forallBases() as a callback.
    ///
    /// \param BaseDefinition the definition of the base class
    ///
    /// \returns true if this base matched the search criteria
    typedef llvm::function_ref<bool(const CXXRecordDecl *BaseDefinition)>
        ForallBasesCallback;
  
    /// \brief Determines if the given callback holds for all the direct
    /// or indirect base classes of this type.
    ///
    /// The class itself does not count as a base class.  This routine
    /// returns false if the class has non-computable base classes.
    ///
    /// \param BaseMatches Callback invoked for each (direct or indirect) base
    /// class of this type, or if \p AllowShortCircuit is true then until a call
    /// returns false.
    ///
    /// \param AllowShortCircuit if false, forces the callback to be called
    /// for every base class, even if a dependent or non-matching base was
    /// found.
    bool forallBases(ForallBasesCallback BaseMatches,
                     bool AllowShortCircuit = true) const;
  
    /// \brief Function type used by lookupInBases() to determine whether a
    /// specific base class subobject matches the lookup criteria.
    ///
    /// \param Specifier the base-class specifier that describes the inheritance
    /// from the base class we are trying to match.
    ///
    /// \param Path the current path, from the most-derived class down to the
    /// base named by the \p Specifier.
    ///
    /// \returns true if this base matched the search criteria, false otherwise.
    typedef llvm::function_ref<bool(const CXXBaseSpecifier *Specifier,
                                    CXXBasePath &Path)> BaseMatchesCallback;
  
    /// \brief Look for entities within the base classes of this C++ class,
    /// transitively searching all base class subobjects.
    ///
    /// This routine uses the callback function \p BaseMatches to find base
    /// classes meeting some search criteria, walking all base class subobjects
    /// and populating the given \p Paths structure with the paths through the
    /// inheritance hierarchy that resulted in a match. On a successful search,
    /// the \p Paths structure can be queried to retrieve the matching paths and
    /// to determine if there were any ambiguities.
    ///
    /// \param BaseMatches callback function used to determine whether a given
    /// base matches the user-defined search criteria.
    ///
    /// \param Paths used to record the paths from this class to its base class
    /// subobjects that match the search criteria.
    ///
    /// \returns true if there exists any path from this class to a base class
    /// subobject that matches the search criteria.
    bool lookupInBases(BaseMatchesCallback BaseMatches,
                       CXXBasePaths &Paths) const;
  
    /// \brief Base-class lookup callback that determines whether the given
    /// base class specifier refers to a specific class declaration.
    ///
    /// This callback can be used with \c lookupInBases() to determine whether
    /// a given derived class has is a base class subobject of a particular type.
    /// The base record pointer should refer to the canonical CXXRecordDecl of the
    /// base class that we are searching for.
    static bool FindBaseClass(const CXXBaseSpecifier *Specifier,
                              CXXBasePath &Path, const CXXRecordDecl *BaseRecord);
  
    /// \brief Base-class lookup callback that determines whether the
    /// given base class specifier refers to a specific class
    /// declaration and describes virtual derivation.
    ///
    /// This callback can be used with \c lookupInBases() to determine
    /// whether a given derived class has is a virtual base class
    /// subobject of a particular type.  The base record pointer should
    /// refer to the canonical CXXRecordDecl of the base class that we
    /// are searching for.
    static bool FindVirtualBaseClass(const CXXBaseSpecifier *Specifier,
                                     CXXBasePath &Path,
                                     const CXXRecordDecl *BaseRecord);
  
    /// \brief Base-class lookup callback that determines whether there exists
    /// a tag with the given name.
    ///
    /// This callback can be used with \c lookupInBases() to find tag members
    /// of the given name within a C++ class hierarchy.
    static bool FindTagMember(const CXXBaseSpecifier *Specifier,
                              CXXBasePath &Path, DeclarationName Name);
  
    /// \brief Base-class lookup callback that determines whether there exists
    /// a member with the given name.
    ///
    /// This callback can be used with \c lookupInBases() to find members
    /// of the given name within a C++ class hierarchy.
    static bool FindOrdinaryMember(const CXXBaseSpecifier *Specifier,
                                   CXXBasePath &Path, DeclarationName Name);
  
    /// \brief Base-class lookup callback that determines whether there exists
    /// an OpenMP declare reduction member with the given name.
    ///
    /// This callback can be used with \c lookupInBases() to find members
    /// of the given name within a C++ class hierarchy.
    static bool FindOMPReductionMember(const CXXBaseSpecifier *Specifier,
                                       CXXBasePath &Path, DeclarationName Name);
  
    /// \brief Base-class lookup callback that determines whether there exists
    /// a member with the given name that can be used in a nested-name-specifier.
    ///
    /// This callback can be used with \c lookupInBases() to find members of
    /// the given name within a C++ class hierarchy that can occur within
    /// nested-name-specifiers.
    static bool FindNestedNameSpecifierMember(const CXXBaseSpecifier *Specifier,
                                              CXXBasePath &Path,
                                              DeclarationName Name);
  
    /// \brief Retrieve the final overriders for each virtual member
    /// function in the class hierarchy where this class is the
    /// most-derived class in the class hierarchy.
    void getFinalOverriders(CXXFinalOverriderMap &FinaOverriders) const;
  
    /// \brief Get the indirect primary bases for this class.
    void getIndirectPrimaryBases(CXXIndirectPrimaryBaseSet& Bases) const;
  
    /// Renders and displays an inheritance diagram
    /// for this C++ class and all of its base classes (transitively) using
    /// GraphViz.
    void viewInheritance(ASTContext& Context) const;
  
    /// \brief Calculates the access of a decl that is reached
    /// along a path.
    static AccessSpecifier MergeAccess(AccessSpecifier PathAccess,
                                       AccessSpecifier DeclAccess) {
      assert(DeclAccess != AS_none);
      if (DeclAccess == AS_private) return AS_none;
      return (PathAccess > DeclAccess ? PathAccess : DeclAccess);
    }
  
    /// \brief Indicates that the declaration of a defaulted or deleted special
    /// member function is now complete.
    void finishedDefaultedOrDeletedMember(CXXMethodDecl *MD);
  
    /// \brief Indicates that the definition of this class is now complete.
    void completeDefinition() override;
  
    /// \brief Indicates that the definition of this class is now complete,
    /// and provides a final overrider map to help determine
    ///
    /// \param FinalOverriders The final overrider map for this class, which can
    /// be provided as an optimization for abstract-class checking. If NULL,
    /// final overriders will be computed if they are needed to complete the
    /// definition.
    void completeDefinition(CXXFinalOverriderMap *FinalOverriders);
  
    /// \brief Determine whether this class may end up being abstract, even though
    /// it is not yet known to be abstract.
    ///
    /// \returns true if this class is not known to be abstract but has any
    /// base classes that are abstract. In this case, \c completeDefinition()
    /// will need to compute final overriders to determine whether the class is
    /// actually abstract.
    bool mayBeAbstract() const;
  
    /// \brief If this is the closure type of a lambda expression, retrieve the
    /// number to be used for name mangling in the Itanium C++ ABI.
    ///
    /// Zero indicates that this closure type has internal linkage, so the 
    /// mangling number does not matter, while a non-zero value indicates which
    /// lambda expression this is in this particular context.
    unsigned getLambdaManglingNumber() const {
      assert(isLambda() && "Not a lambda closure type!");
      return getLambdaData().ManglingNumber;
    }
    
    /// \brief Retrieve the declaration that provides additional context for a 
    /// lambda, when the normal declaration context is not specific enough.
    ///
    /// Certain contexts (default arguments of in-class function parameters and 
    /// the initializers of data members) have separate name mangling rules for
    /// lambdas within the Itanium C++ ABI. For these cases, this routine provides
    /// the declaration in which the lambda occurs, e.g., the function parameter 
    /// or the non-static data member. Otherwise, it returns NULL to imply that
    /// the declaration context suffices.
    Decl *getLambdaContextDecl() const {
      assert(isLambda() && "Not a lambda closure type!");
      return getLambdaData().ContextDecl;    
    }
    
    /// \brief Set the mangling number and context declaration for a lambda
    /// class.
    void setLambdaMangling(unsigned ManglingNumber, Decl *ContextDecl) {
      getLambdaData().ManglingNumber = ManglingNumber;
      getLambdaData().ContextDecl = ContextDecl;
    }
  
    /// \brief Returns the inheritance model used for this record.
    MSInheritanceAttr::Spelling getMSInheritanceModel() const;
    /// \brief Calculate what the inheritance model would be for this class.
    MSInheritanceAttr::Spelling calculateInheritanceModel() const;
  
    /// In the Microsoft C++ ABI, use zero for the field offset of a null data
    /// member pointer if we can guarantee that zero is not a valid field offset,
    /// or if the member pointer has multiple fields.  Polymorphic classes have a
    /// vfptr at offset zero, so we can use zero for null.  If there are multiple
    /// fields, we can use zero even if it is a valid field offset because
    /// null-ness testing will check the other fields.
    bool nullFieldOffsetIsZero() const {
      return !MSInheritanceAttr::hasOnlyOneField(/*IsMemberFunction=*/false,
                                                 getMSInheritanceModel()) ||
             (hasDefinition() && isPolymorphic());
    }
  
    /// \brief Controls when vtordisps will be emitted if this record is used as a
    /// virtual base.
    MSVtorDispAttr::Mode getMSVtorDispMode() const;
  
    /// \brief Determine whether this lambda expression was known to be dependent
    /// at the time it was created, even if its context does not appear to be
    /// dependent.
    ///
    /// This flag is a workaround for an issue with parsing, where default
    /// arguments are parsed before their enclosing function declarations have
    /// been created. This means that any lambda expressions within those
    /// default arguments will have as their DeclContext the context enclosing
    /// the function declaration, which may be non-dependent even when the
    /// function declaration itself is dependent. This flag indicates when we
    /// know that the lambda is dependent despite that.
    bool isDependentLambda() const {
      return isLambda() && getLambdaData().Dependent;
    }
  
    TypeSourceInfo *getLambdaTypeInfo() const {
      return getLambdaData().MethodTyInfo;
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) {
      return K >= firstCXXRecord && K <= lastCXXRecord;
    }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
    friend class ASTRecordWriter;
    friend class ASTReader;
    friend class ASTWriter;
  };
  
  /// \brief Represents a static or instance method of a struct/union/class.
  ///
  /// In the terminology of the C++ Standard, these are the (static and
  /// non-static) member functions, whether virtual or not.
  class CXXMethodDecl : public FunctionDecl {
    void anchor() override;
  protected:
    CXXMethodDecl(Kind DK, ASTContext &C, CXXRecordDecl *RD,
                  SourceLocation StartLoc, const DeclarationNameInfo &NameInfo,
                  QualType T, TypeSourceInfo *TInfo,
                  StorageClass SC, bool isInline,
                  bool isConstexpr, SourceLocation EndLocation)
      : FunctionDecl(DK, C, RD, StartLoc, NameInfo, T, TInfo,
                     SC, isInline, isConstexpr) {
      if (EndLocation.isValid())
        setRangeEnd(EndLocation);
    }
  
  public:
    static CXXMethodDecl *Create(ASTContext &C, CXXRecordDecl *RD,
                                 SourceLocation StartLoc,
                                 const DeclarationNameInfo &NameInfo,
                                 QualType T, TypeSourceInfo *TInfo,
                                 StorageClass SC,
                                 bool isInline,
                                 bool isConstexpr,
                                 SourceLocation EndLocation);
  
    static CXXMethodDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    bool isStatic() const;
    bool isInstance() const { return !isStatic(); }
  
    /// Returns true if the given operator is implicitly static in a record
    /// context.
    static bool isStaticOverloadedOperator(OverloadedOperatorKind OOK) {
      // [class.free]p1:
      // Any allocation function for a class T is a static member
      // (even if not explicitly declared static).
      // [class.free]p6 Any deallocation function for a class X is a static member
      // (even if not explicitly declared static).
      return OOK == OO_New || OOK == OO_Array_New || OOK == OO_Delete ||
             OOK == OO_Array_Delete;
    }
  
    bool isConst() const { return getType()->castAs<FunctionType>()->isConst(); }
    bool isVolatile() const { return getType()->castAs<FunctionType>()->isVolatile(); }
  
    bool isVirtual() const {
      CXXMethodDecl *CD =
        cast<CXXMethodDecl>(const_cast<CXXMethodDecl*>(this)->getCanonicalDecl());
  
      // Member function is virtual if it is marked explicitly so, or if it is
      // declared in __interface -- then it is automatically pure virtual.
      if (CD->isVirtualAsWritten() || CD->isPure())
        return true;
  
      return (CD->begin_overridden_methods() != CD->end_overridden_methods());
    }
  
    /// \brief Determine whether this is a usual deallocation function
    /// (C++ [basic.stc.dynamic.deallocation]p2), which is an overloaded
    /// delete or delete[] operator with a particular signature.
    bool isUsualDeallocationFunction() const;
  
    /// \brief Determine whether this is a copy-assignment operator, regardless
    /// of whether it was declared implicitly or explicitly.
    bool isCopyAssignmentOperator() const;
  
    /// \brief Determine whether this is a move assignment operator.
    bool isMoveAssignmentOperator() const;
  
    CXXMethodDecl *getCanonicalDecl() override {
      return cast<CXXMethodDecl>(FunctionDecl::getCanonicalDecl());
    }
    const CXXMethodDecl *getCanonicalDecl() const {
      return const_cast<CXXMethodDecl*>(this)->getCanonicalDecl();
    }
  
    CXXMethodDecl *getMostRecentDecl() {
      return cast<CXXMethodDecl>(
              static_cast<FunctionDecl *>(this)->getMostRecentDecl());
    }
    const CXXMethodDecl *getMostRecentDecl() const {
      return const_cast<CXXMethodDecl*>(this)->getMostRecentDecl();
    }
  
    /// True if this method is user-declared and was not
    /// deleted or defaulted on its first declaration.
    bool isUserProvided() const {
      return !(isDeleted() || getCanonicalDecl()->isDefaulted());
    }
  
    ///
    void addOverriddenMethod(const CXXMethodDecl *MD);
  
    typedef const CXXMethodDecl *const* method_iterator;
  
    method_iterator begin_overridden_methods() const;
    method_iterator end_overridden_methods() const;
    unsigned size_overridden_methods() const;
    typedef ASTContext::overridden_method_range overridden_method_range;
    overridden_method_range overridden_methods() const;
  
    /// Returns the parent of this method declaration, which
    /// is the class in which this method is defined.
    const CXXRecordDecl *getParent() const {
      return cast<CXXRecordDecl>(FunctionDecl::getParent());
    }
  
    /// Returns the parent of this method declaration, which
    /// is the class in which this method is defined.
    CXXRecordDecl *getParent() {
      return const_cast<CXXRecordDecl *>(
               cast<CXXRecordDecl>(FunctionDecl::getParent()));
    }
  
    /// \brief Returns the type of the \c this pointer.
    ///
    /// Should only be called for instance (i.e., non-static) methods.
    QualType getThisType(ASTContext &C) const;
  
    unsigned getTypeQualifiers() const {
      return getType()->getAs<FunctionProtoType>()->getTypeQuals();
    }
  
    /// \brief Retrieve the ref-qualifier associated with this method.
    ///
    /// In the following example, \c f() has an lvalue ref-qualifier, \c g()
    /// has an rvalue ref-qualifier, and \c h() has no ref-qualifier.
    /// @code
    /// struct X {
    ///   void f() &;
    ///   void g() &&;
    ///   void h();
    /// };
    /// @endcode
    RefQualifierKind getRefQualifier() const {
      return getType()->getAs<FunctionProtoType>()->getRefQualifier();
    }
  
    bool hasInlineBody() const;
  
    /// \brief Determine whether this is a lambda closure type's static member
    /// function that is used for the result of the lambda's conversion to
    /// function pointer (for a lambda with no captures).
    ///
    /// The function itself, if used, will have a placeholder body that will be
    /// supplied by IR generation to either forward to the function call operator
    /// or clone the function call operator.
    bool isLambdaStaticInvoker() const;
  
    /// \brief Find the method in \p RD that corresponds to this one.
    ///
    /// Find if \p RD or one of the classes it inherits from override this method.
    /// If so, return it. \p RD is assumed to be a subclass of the class defining
    /// this method (or be the class itself), unless \p MayBeBase is set to true.
    CXXMethodDecl *
    getCorrespondingMethodInClass(const CXXRecordDecl *RD,
                                  bool MayBeBase = false);
  
    const CXXMethodDecl *
    getCorrespondingMethodInClass(const CXXRecordDecl *RD,
                                  bool MayBeBase = false) const {
      return const_cast<CXXMethodDecl *>(this)
                ->getCorrespondingMethodInClass(RD, MayBeBase);
    }
  
    // Implement isa/cast/dyncast/etc.
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) {
      return K >= firstCXXMethod && K <= lastCXXMethod;
    }
  };
  
  /// \brief Represents a C++ base or member initializer.
  ///
  /// This is part of a constructor initializer that
  /// initializes one non-static member variable or one base class. For
  /// example, in the following, both 'A(a)' and 'f(3.14159)' are member
  /// initializers:
  ///
  /// \code
  /// class A { };
  /// class B : public A {
  ///   float f;
  /// public:
  ///   B(A& a) : A(a), f(3.14159) { }
  /// };
  /// \endcode
  class CXXCtorInitializer final
      : private llvm::TrailingObjects<CXXCtorInitializer, VarDecl *> {
    /// \brief Either the base class name/delegating constructor type (stored as
    /// a TypeSourceInfo*), an normal field (FieldDecl), or an anonymous field
    /// (IndirectFieldDecl*) being initialized.
    llvm::PointerUnion3<TypeSourceInfo *, FieldDecl *, IndirectFieldDecl *>
      Initializee;
  
    /// \brief The source location for the field name or, for a base initializer
    /// pack expansion, the location of the ellipsis.
    ///
    /// In the case of a delegating
    /// constructor, it will still include the type's source location as the
    /// Initializee points to the CXXConstructorDecl (to allow loop detection).
    SourceLocation MemberOrEllipsisLocation;
  
    /// \brief The argument used to initialize the base or member, which may
    /// end up constructing an object (when multiple arguments are involved).
    Stmt *Init;
  
    /// \brief Location of the left paren of the ctor-initializer.
    SourceLocation LParenLoc;
  
    /// \brief Location of the right paren of the ctor-initializer.
    SourceLocation RParenLoc;
  
    /// \brief If the initializee is a type, whether that type makes this
    /// a delegating initialization.
    unsigned IsDelegating : 1;
  
    /// \brief If the initializer is a base initializer, this keeps track
    /// of whether the base is virtual or not.
    unsigned IsVirtual : 1;
  
    /// \brief Whether or not the initializer is explicitly written
    /// in the sources.
    unsigned IsWritten : 1;
  
    /// If IsWritten is true, then this number keeps track of the textual order
    /// of this initializer in the original sources, counting from 0; otherwise,
    /// it stores the number of array index variables stored after this object
    /// in memory.
    unsigned SourceOrderOrNumArrayIndices : 13;
  
    CXXCtorInitializer(ASTContext &Context, FieldDecl *Member,
                       SourceLocation MemberLoc, SourceLocation L, Expr *Init,
                       SourceLocation R, VarDecl **Indices, unsigned NumIndices);
  
  public:
    /// \brief Creates a new base-class initializer.
    explicit
    CXXCtorInitializer(ASTContext &Context, TypeSourceInfo *TInfo, bool IsVirtual,
                       SourceLocation L, Expr *Init, SourceLocation R,
                       SourceLocation EllipsisLoc);
  
    /// \brief Creates a new member initializer.
    explicit
    CXXCtorInitializer(ASTContext &Context, FieldDecl *Member,
                       SourceLocation MemberLoc, SourceLocation L, Expr *Init,
                       SourceLocation R);
  
    /// \brief Creates a new anonymous field initializer.
    explicit
    CXXCtorInitializer(ASTContext &Context, IndirectFieldDecl *Member,
                       SourceLocation MemberLoc, SourceLocation L, Expr *Init,
                       SourceLocation R);
  
    /// \brief Creates a new delegating initializer.
    explicit
    CXXCtorInitializer(ASTContext &Context, TypeSourceInfo *TInfo,
                       SourceLocation L, Expr *Init, SourceLocation R);
  
    /// \brief Creates a new member initializer that optionally contains
    /// array indices used to describe an elementwise initialization.
    static CXXCtorInitializer *Create(ASTContext &Context, FieldDecl *Member,
                                      SourceLocation MemberLoc, SourceLocation L,
                                      Expr *Init, SourceLocation R,
                                      VarDecl **Indices, unsigned NumIndices);
  
    /// \brief Determine whether this initializer is initializing a base class.
    bool isBaseInitializer() const {
      return Initializee.is<TypeSourceInfo*>() && !IsDelegating;
    }
  
    /// \brief Determine whether this initializer is initializing a non-static
    /// data member.
    bool isMemberInitializer() const { return Initializee.is<FieldDecl*>(); }
  
    bool isAnyMemberInitializer() const {
      return isMemberInitializer() || isIndirectMemberInitializer();
    }
  
    bool isIndirectMemberInitializer() const {
      return Initializee.is<IndirectFieldDecl*>();
    }
  
    /// \brief Determine whether this initializer is an implicit initializer
    /// generated for a field with an initializer defined on the member
    /// declaration.
    ///
    /// In-class member initializers (also known as "non-static data member
    /// initializations", NSDMIs) were introduced in C++11.
    bool isInClassMemberInitializer() const {
      return Init->getStmtClass() == Stmt::CXXDefaultInitExprClass;
    }
  
    /// \brief Determine whether this initializer is creating a delegating
    /// constructor.
    bool isDelegatingInitializer() const {
      return Initializee.is<TypeSourceInfo*>() && IsDelegating;
    }
  
    /// \brief Determine whether this initializer is a pack expansion.
    bool isPackExpansion() const {
      return isBaseInitializer() && MemberOrEllipsisLocation.isValid();
    }
  
    // \brief For a pack expansion, returns the location of the ellipsis.
    SourceLocation getEllipsisLoc() const {
      assert(isPackExpansion() && "Initializer is not a pack expansion");
      return MemberOrEllipsisLocation;
    }
  
    /// If this is a base class initializer, returns the type of the
    /// base class with location information. Otherwise, returns an NULL
    /// type location.
    TypeLoc getBaseClassLoc() const;
  
    /// If this is a base class initializer, returns the type of the base class.
    /// Otherwise, returns null.
    const Type *getBaseClass() const;
  
    /// Returns whether the base is virtual or not.
    bool isBaseVirtual() const {
      assert(isBaseInitializer() && "Must call this on base initializer!");
  
      return IsVirtual;
    }
  
    /// \brief Returns the declarator information for a base class or delegating
    /// initializer.
    TypeSourceInfo *getTypeSourceInfo() const {
      return Initializee.dyn_cast<TypeSourceInfo *>();
    }
  
    /// \brief If this is a member initializer, returns the declaration of the
    /// non-static data member being initialized. Otherwise, returns null.
    FieldDecl *getMember() const {
      if (isMemberInitializer())
        return Initializee.get<FieldDecl*>();
      return nullptr;
    }
    FieldDecl *getAnyMember() const {
      if (isMemberInitializer())
        return Initializee.get<FieldDecl*>();
      if (isIndirectMemberInitializer())
        return Initializee.get<IndirectFieldDecl*>()->getAnonField();
      return nullptr;
    }
  
    IndirectFieldDecl *getIndirectMember() const {
      if (isIndirectMemberInitializer())
        return Initializee.get<IndirectFieldDecl*>();
      return nullptr;
    }
  
    SourceLocation getMemberLocation() const {
      return MemberOrEllipsisLocation;
    }
  
    /// \brief Determine the source location of the initializer.
    SourceLocation getSourceLocation() const;
  
    /// \brief Determine the source range covering the entire initializer.
    SourceRange getSourceRange() const LLVM_READONLY;
  
    /// \brief Determine whether this initializer is explicitly written
    /// in the source code.
    bool isWritten() const { return IsWritten; }
  
    /// \brief Return the source position of the initializer, counting from 0.
    /// If the initializer was implicit, -1 is returned.
    int getSourceOrder() const {
      return IsWritten ? static_cast<int>(SourceOrderOrNumArrayIndices) : -1;
    }
  
    /// \brief Set the source order of this initializer.
    ///
    /// This can only be called once for each initializer; it cannot be called
    /// on an initializer having a positive number of (implicit) array indices.
    ///
    /// This assumes that the initializer was written in the source code, and
    /// ensures that isWritten() returns true.
    void setSourceOrder(int pos) {
      assert(!IsWritten &&
             "calling twice setSourceOrder() on the same initializer");
      assert(SourceOrderOrNumArrayIndices == 0 &&
             "setSourceOrder() used when there are implicit array indices");
      assert(pos >= 0 &&
             "setSourceOrder() used to make an initializer implicit");
      IsWritten = true;
      SourceOrderOrNumArrayIndices = static_cast<unsigned>(pos);
    }
  
    SourceLocation getLParenLoc() const { return LParenLoc; }
    SourceLocation getRParenLoc() const { return RParenLoc; }
  
    /// \brief Determine the number of implicit array indices used while
    /// described an array member initialization.
    unsigned getNumArrayIndices() const {
      return IsWritten ? 0 : SourceOrderOrNumArrayIndices;
    }
  
    /// \brief Retrieve a particular array index variable used to
    /// describe an array member initialization.
    VarDecl *getArrayIndex(unsigned I) {
      assert(I < getNumArrayIndices() && "Out of bounds member array index");
      return getTrailingObjects<VarDecl *>()[I];
    }
    const VarDecl *getArrayIndex(unsigned I) const {
      assert(I < getNumArrayIndices() && "Out of bounds member array index");
      return getTrailingObjects<VarDecl *>()[I];
    }
    void setArrayIndex(unsigned I, VarDecl *Index) {
      assert(I < getNumArrayIndices() && "Out of bounds member array index");
      getTrailingObjects<VarDecl *>()[I] = Index;
    }
    ArrayRef<VarDecl *> getArrayIndices() {
      return llvm::makeArrayRef(getTrailingObjects<VarDecl *>(),
                                getNumArrayIndices());
    }
  
    /// \brief Get the initializer.
    Expr *getInit() const { return static_cast<Expr*>(Init); }
  
    friend TrailingObjects;
  };
  
  /// Description of a constructor that was inherited from a base class.
  class InheritedConstructor {
    ConstructorUsingShadowDecl *Shadow;
    CXXConstructorDecl *BaseCtor;
  
  public:
    InheritedConstructor() : Shadow(), BaseCtor() {}
    InheritedConstructor(ConstructorUsingShadowDecl *Shadow,
                         CXXConstructorDecl *BaseCtor)
        : Shadow(Shadow), BaseCtor(BaseCtor) {}
  
    explicit operator bool() const { return Shadow; }
  
    ConstructorUsingShadowDecl *getShadowDecl() const { return Shadow; }
    CXXConstructorDecl *getConstructor() const { return BaseCtor; }
  };
  
  /// \brief Represents a C++ constructor within a class.
  ///
  /// For example:
  ///
  /// \code
  /// class X {
  /// public:
  ///   explicit X(int); // represented by a CXXConstructorDecl.
  /// };
  /// \endcode
  class CXXConstructorDecl final
      : public CXXMethodDecl,
        private llvm::TrailingObjects<CXXConstructorDecl, InheritedConstructor> {
    void anchor() override;
  
    /// \name Support for base and member initializers.
    /// \{
    /// \brief The arguments used to initialize the base or member.
    LazyCXXCtorInitializersPtr CtorInitializers;
    unsigned NumCtorInitializers : 30;
    /// \}
  
    /// \brief Whether this constructor declaration has the \c explicit keyword
    /// specified.
    unsigned IsExplicitSpecified : 1;
  
    /// \brief Whether this constructor declaration is an implicitly-declared
    /// inheriting constructor.
    unsigned IsInheritingConstructor : 1;
  
    CXXConstructorDecl(ASTContext &C, CXXRecordDecl *RD, SourceLocation StartLoc,
                       const DeclarationNameInfo &NameInfo,
                       QualType T, TypeSourceInfo *TInfo,
                       bool isExplicitSpecified, bool isInline,
                       bool isImplicitlyDeclared, bool isConstexpr,
                       InheritedConstructor Inherited)
      : CXXMethodDecl(CXXConstructor, C, RD, StartLoc, NameInfo, T, TInfo,
                      SC_None, isInline, isConstexpr, SourceLocation()),
        CtorInitializers(nullptr), NumCtorInitializers(0),
        IsExplicitSpecified(isExplicitSpecified),
        IsInheritingConstructor((bool)Inherited) {
      setImplicit(isImplicitlyDeclared);
      if (Inherited)
        *getTrailingObjects<InheritedConstructor>() = Inherited;
    }
  
  public:
    static CXXConstructorDecl *CreateDeserialized(ASTContext &C, unsigned ID,
                                                  bool InheritsConstructor);
    static CXXConstructorDecl *
    Create(ASTContext &C, CXXRecordDecl *RD, SourceLocation StartLoc,
           const DeclarationNameInfo &NameInfo, QualType T, TypeSourceInfo *TInfo,
           bool isExplicit, bool isInline, bool isImplicitlyDeclared,
           bool isConstexpr,
           InheritedConstructor Inherited = InheritedConstructor());
  
    /// \brief Determine whether this constructor declaration has the
    /// \c explicit keyword specified.
    bool isExplicitSpecified() const { return IsExplicitSpecified; }
  
    /// \brief Determine whether this constructor was marked "explicit" or not.
    bool isExplicit() const {
      return cast<CXXConstructorDecl>(getFirstDecl())->isExplicitSpecified();
    }
  
    /// \brief Iterates through the member/base initializer list.
    typedef CXXCtorInitializer **init_iterator;
  
    /// \brief Iterates through the member/base initializer list.
    typedef CXXCtorInitializer *const *init_const_iterator;
  
    typedef llvm::iterator_range<init_iterator> init_range;
    typedef llvm::iterator_range<init_const_iterator> init_const_range;
  
    init_range inits() { return init_range(init_begin(), init_end()); }
    init_const_range inits() const {
      return init_const_range(init_begin(), init_end());
    }
  
    /// \brief Retrieve an iterator to the first initializer.
    init_iterator init_begin() {
      const auto *ConstThis = this;
      return const_cast<init_iterator>(ConstThis->init_begin());
    }
    /// \brief Retrieve an iterator to the first initializer.
    init_const_iterator init_begin() const;
  
    /// \brief Retrieve an iterator past the last initializer.
    init_iterator       init_end()       {
      return init_begin() + NumCtorInitializers;
    }
    /// \brief Retrieve an iterator past the last initializer.
    init_const_iterator init_end() const {
      return init_begin() + NumCtorInitializers;
    }
  
    typedef std::reverse_iterator<init_iterator> init_reverse_iterator;
    typedef std::reverse_iterator<init_const_iterator>
            init_const_reverse_iterator;
  
    init_reverse_iterator init_rbegin() {
      return init_reverse_iterator(init_end());
    }
    init_const_reverse_iterator init_rbegin() const {
      return init_const_reverse_iterator(init_end());
    }
  
    init_reverse_iterator init_rend() {
      return init_reverse_iterator(init_begin());
    }
    init_const_reverse_iterator init_rend() const {
      return init_const_reverse_iterator(init_begin());
    }
  
    /// \brief Determine the number of arguments used to initialize the member
    /// or base.
    unsigned getNumCtorInitializers() const {
        return NumCtorInitializers;
    }
  
    void setNumCtorInitializers(unsigned numCtorInitializers) {
      NumCtorInitializers = numCtorInitializers;
    }
  
    void setCtorInitializers(CXXCtorInitializer **Initializers) {
      CtorInitializers = Initializers;
    }
  
    /// \brief Determine whether this constructor is a delegating constructor.
    bool isDelegatingConstructor() const {
      return (getNumCtorInitializers() == 1) &&
             init_begin()[0]->isDelegatingInitializer();
    }
  
    /// \brief When this constructor delegates to another, retrieve the target.
    CXXConstructorDecl *getTargetConstructor() const;
  
    /// Whether this constructor is a default
    /// constructor (C++ [class.ctor]p5), which can be used to
    /// default-initialize a class of this type.
    bool isDefaultConstructor() const;
  
    /// \brief Whether this constructor is a copy constructor (C++ [class.copy]p2,
    /// which can be used to copy the class.
    ///
    /// \p TypeQuals will be set to the qualifiers on the
    /// argument type. For example, \p TypeQuals would be set to \c
    /// Qualifiers::Const for the following copy constructor:
    ///
    /// \code
    /// class X {
    /// public:
    ///   X(const X&);
    /// };
    /// \endcode
    bool isCopyConstructor(unsigned &TypeQuals) const;
  
    /// Whether this constructor is a copy
    /// constructor (C++ [class.copy]p2, which can be used to copy the
    /// class.
    bool isCopyConstructor() const {
      unsigned TypeQuals = 0;
      return isCopyConstructor(TypeQuals);
    }
  
    /// \brief Determine whether this constructor is a move constructor
    /// (C++11 [class.copy]p3), which can be used to move values of the class.
    ///
    /// \param TypeQuals If this constructor is a move constructor, will be set
    /// to the type qualifiers on the referent of the first parameter's type.
    bool isMoveConstructor(unsigned &TypeQuals) const;
  
    /// \brief Determine whether this constructor is a move constructor
    /// (C++11 [class.copy]p3), which can be used to move values of the class.
    bool isMoveConstructor() const {
      unsigned TypeQuals = 0;
      return isMoveConstructor(TypeQuals);
    }
  
    /// \brief Determine whether this is a copy or move constructor.
    ///
    /// \param TypeQuals Will be set to the type qualifiers on the reference
    /// parameter, if in fact this is a copy or move constructor.
    bool isCopyOrMoveConstructor(unsigned &TypeQuals) const;
  
    /// \brief Determine whether this a copy or move constructor.
    bool isCopyOrMoveConstructor() const {
      unsigned Quals;
      return isCopyOrMoveConstructor(Quals);
    }
  
    /// Whether this constructor is a
    /// converting constructor (C++ [class.conv.ctor]), which can be
    /// used for user-defined conversions.
    bool isConvertingConstructor(bool AllowExplicit) const;
  
    /// \brief Determine whether this is a member template specialization that
    /// would copy the object to itself. Such constructors are never used to copy
    /// an object.
    bool isSpecializationCopyingObject() const;
  
    /// \brief Determine whether this is an implicit constructor synthesized to
    /// model a call to a constructor inherited from a base class.
    bool isInheritingConstructor() const { return IsInheritingConstructor; }
  
    /// \brief Get the constructor that this inheriting constructor is based on.
    InheritedConstructor getInheritedConstructor() const {
      return IsInheritingConstructor ? *getTrailingObjects<InheritedConstructor>()
                                     : InheritedConstructor();
    }
  
    CXXConstructorDecl *getCanonicalDecl() override {
      return cast<CXXConstructorDecl>(FunctionDecl::getCanonicalDecl());
    }
    const CXXConstructorDecl *getCanonicalDecl() const {
      return const_cast<CXXConstructorDecl*>(this)->getCanonicalDecl();
    }
  
    // Implement isa/cast/dyncast/etc.
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == CXXConstructor; }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
    friend TrailingObjects;
  };
  
  /// \brief Represents a C++ destructor within a class.
  ///
  /// For example:
  ///
  /// \code
  /// class X {
  /// public:
  ///   ~X(); // represented by a CXXDestructorDecl.
  /// };
  /// \endcode
  class CXXDestructorDecl : public CXXMethodDecl {
    void anchor() override;
  
    FunctionDecl *OperatorDelete;
  
    CXXDestructorDecl(ASTContext &C, CXXRecordDecl *RD, SourceLocation StartLoc,
                      const DeclarationNameInfo &NameInfo,
                      QualType T, TypeSourceInfo *TInfo,
                      bool isInline, bool isImplicitlyDeclared)
      : CXXMethodDecl(CXXDestructor, C, RD, StartLoc, NameInfo, T, TInfo,
                      SC_None, isInline, /*isConstexpr=*/false, SourceLocation()),
        OperatorDelete(nullptr) {
      setImplicit(isImplicitlyDeclared);
    }
  
  public:
    static CXXDestructorDecl *Create(ASTContext &C, CXXRecordDecl *RD,
                                     SourceLocation StartLoc,
                                     const DeclarationNameInfo &NameInfo,
                                     QualType T, TypeSourceInfo* TInfo,
                                     bool isInline,
                                     bool isImplicitlyDeclared);
    static CXXDestructorDecl *CreateDeserialized(ASTContext & C, unsigned ID);
  
    void setOperatorDelete(FunctionDecl *OD);
    const FunctionDecl *getOperatorDelete() const {
      return cast<CXXDestructorDecl>(getFirstDecl())->OperatorDelete;
    }
  
    // Implement isa/cast/dyncast/etc.
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == CXXDestructor; }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
  };
  
  /// \brief Represents a C++ conversion function within a class.
  ///
  /// For example:
  ///
  /// \code
  /// class X {
  /// public:
  ///   operator bool();
  /// };
  /// \endcode
  class CXXConversionDecl : public CXXMethodDecl {
    void anchor() override;
    /// Whether this conversion function declaration is marked
    /// "explicit", meaning that it can only be applied when the user
    /// explicitly wrote a cast. This is a C++11 feature.
    bool IsExplicitSpecified : 1;
  
    CXXConversionDecl(ASTContext &C, CXXRecordDecl *RD, SourceLocation StartLoc,
                      const DeclarationNameInfo &NameInfo,
                      QualType T, TypeSourceInfo *TInfo,
                      bool isInline, bool isExplicitSpecified,
                      bool isConstexpr, SourceLocation EndLocation)
      : CXXMethodDecl(CXXConversion, C, RD, StartLoc, NameInfo, T, TInfo,
                      SC_None, isInline, isConstexpr, EndLocation),
        IsExplicitSpecified(isExplicitSpecified) { }
  
  public:
    static CXXConversionDecl *Create(ASTContext &C, CXXRecordDecl *RD,
                                     SourceLocation StartLoc,
                                     const DeclarationNameInfo &NameInfo,
                                     QualType T, TypeSourceInfo *TInfo,
                                     bool isInline, bool isExplicit,
                                     bool isConstexpr,
                                     SourceLocation EndLocation);
    static CXXConversionDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    /// Whether this conversion function declaration is marked
    /// "explicit", meaning that it can only be used for direct initialization
    /// (including explitly written casts).  This is a C++11 feature.
    bool isExplicitSpecified() const { return IsExplicitSpecified; }
  
    /// \brief Whether this is an explicit conversion operator (C++11 and later).
    ///
    /// Explicit conversion operators are only considered for direct
    /// initialization, e.g., when the user has explicitly written a cast.
    bool isExplicit() const {
      return cast<CXXConversionDecl>(getFirstDecl())->isExplicitSpecified();
    }
  
    /// \brief Returns the type that this conversion function is converting to.
    QualType getConversionType() const {
      return getType()->getAs<FunctionType>()->getReturnType();
    }
  
    /// \brief Determine whether this conversion function is a conversion from
    /// a lambda closure type to a block pointer.
    bool isLambdaToBlockPointerConversion() const;
    
    // Implement isa/cast/dyncast/etc.
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == CXXConversion; }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
  };
  
  /// \brief Represents a linkage specification. 
  ///
  /// For example:
  /// \code
  ///   extern "C" void foo();
  /// \endcode
  class LinkageSpecDecl : public Decl, public DeclContext {
    virtual void anchor();
  public:
    /// \brief Represents the language in a linkage specification.
    ///
    /// The values are part of the serialization ABI for
    /// ASTs and cannot be changed without altering that ABI.  To help
    /// ensure a stable ABI for this, we choose the DW_LANG_ encodings
    /// from the dwarf standard.
    enum LanguageIDs {
      lang_c = /* DW_LANG_C */ 0x0002,
      lang_cxx = /* DW_LANG_C_plus_plus */ 0x0004
    };
  private:
    /// \brief The language for this linkage specification.
    unsigned Language : 3;
    /// \brief True if this linkage spec has braces.
    ///
    /// This is needed so that hasBraces() returns the correct result while the
    /// linkage spec body is being parsed.  Once RBraceLoc has been set this is
    /// not used, so it doesn't need to be serialized.
    unsigned HasBraces : 1;
    /// \brief The source location for the extern keyword.
    SourceLocation ExternLoc;
    /// \brief The source location for the right brace (if valid).
    SourceLocation RBraceLoc;
  
    LinkageSpecDecl(DeclContext *DC, SourceLocation ExternLoc,
                    SourceLocation LangLoc, LanguageIDs lang, bool HasBraces)
      : Decl(LinkageSpec, DC, LangLoc), DeclContext(LinkageSpec),
        Language(lang), HasBraces(HasBraces), ExternLoc(ExternLoc),
        RBraceLoc(SourceLocation()) { }
  
  public:
    static LinkageSpecDecl *Create(ASTContext &C, DeclContext *DC,
                                   SourceLocation ExternLoc,
                                   SourceLocation LangLoc, LanguageIDs Lang,
                                   bool HasBraces);
    static LinkageSpecDecl *CreateDeserialized(ASTContext &C, unsigned ID);
    
    /// \brief Return the language specified by this linkage specification.
    LanguageIDs getLanguage() const { return LanguageIDs(Language); }
    /// \brief Set the language specified by this linkage specification.
    void setLanguage(LanguageIDs L) { Language = L; }
  
    /// \brief Determines whether this linkage specification had braces in
    /// its syntactic form.
    bool hasBraces() const {
      assert(!RBraceLoc.isValid() || HasBraces);
      return HasBraces;
    }
  
    SourceLocation getExternLoc() const { return ExternLoc; }
    SourceLocation getRBraceLoc() const { return RBraceLoc; }
    void setExternLoc(SourceLocation L) { ExternLoc = L; }
    void setRBraceLoc(SourceLocation L) {
      RBraceLoc = L;
      HasBraces = RBraceLoc.isValid();
    }
  
    SourceLocation getLocEnd() const LLVM_READONLY {
      if (hasBraces())
        return getRBraceLoc();
      // No braces: get the end location of the (only) declaration in context
      // (if present).
      return decls_empty() ? getLocation() : decls_begin()->getLocEnd();
    }
  
    SourceRange getSourceRange() const override LLVM_READONLY {
      return SourceRange(ExternLoc, getLocEnd());
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == LinkageSpec; }
    static DeclContext *castToDeclContext(const LinkageSpecDecl *D) {
      return static_cast<DeclContext *>(const_cast<LinkageSpecDecl*>(D));
    }
    static LinkageSpecDecl *castFromDeclContext(const DeclContext *DC) {
      return static_cast<LinkageSpecDecl *>(const_cast<DeclContext*>(DC));
    }
  };
  
  /// \brief Represents C++ using-directive.
  ///
  /// For example:
  /// \code
  ///    using namespace std;
  /// \endcode
  ///
  /// \note UsingDirectiveDecl should be Decl not NamedDecl, but we provide
  /// artificial names for all using-directives in order to store
  /// them in DeclContext effectively.
  class UsingDirectiveDecl : public NamedDecl {
    void anchor() override;
    /// \brief The location of the \c using keyword.
    SourceLocation UsingLoc;
  
    /// \brief The location of the \c namespace keyword.
    SourceLocation NamespaceLoc;
  
    /// \brief The nested-name-specifier that precedes the namespace.
    NestedNameSpecifierLoc QualifierLoc;
  
    /// \brief The namespace nominated by this using-directive.
    NamedDecl *NominatedNamespace;
  
    /// Enclosing context containing both using-directive and nominated
    /// namespace.
    DeclContext *CommonAncestor;
  
    /// \brief Returns special DeclarationName used by using-directives.
    ///
    /// This is only used by DeclContext for storing UsingDirectiveDecls in
    /// its lookup structure.
    static DeclarationName getName() {
      return DeclarationName::getUsingDirectiveName();
    }
  
    UsingDirectiveDecl(DeclContext *DC, SourceLocation UsingLoc,
                       SourceLocation NamespcLoc,
                       NestedNameSpecifierLoc QualifierLoc,
                       SourceLocation IdentLoc,
                       NamedDecl *Nominated,
                       DeclContext *CommonAncestor)
      : NamedDecl(UsingDirective, DC, IdentLoc, getName()), UsingLoc(UsingLoc),
        NamespaceLoc(NamespcLoc), QualifierLoc(QualifierLoc),
        NominatedNamespace(Nominated), CommonAncestor(CommonAncestor) { }
  
  public:
    /// \brief Retrieve the nested-name-specifier that qualifies the
    /// name of the namespace, with source-location information.
    NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the
    /// name of the namespace.
    NestedNameSpecifier *getQualifier() const {
      return QualifierLoc.getNestedNameSpecifier();
    }
  
    NamedDecl *getNominatedNamespaceAsWritten() { return NominatedNamespace; }
    const NamedDecl *getNominatedNamespaceAsWritten() const {
      return NominatedNamespace;
    }
  
    /// \brief Returns the namespace nominated by this using-directive.
    NamespaceDecl *getNominatedNamespace();
  
    const NamespaceDecl *getNominatedNamespace() const {
      return const_cast<UsingDirectiveDecl*>(this)->getNominatedNamespace();
    }
  
    /// \brief Returns the common ancestor context of this using-directive and
    /// its nominated namespace.
    DeclContext *getCommonAncestor() { return CommonAncestor; }
    const DeclContext *getCommonAncestor() const { return CommonAncestor; }
  
    /// \brief Return the location of the \c using keyword.
    SourceLocation getUsingLoc() const { return UsingLoc; }
  
    // FIXME: Could omit 'Key' in name.
    /// \brief Returns the location of the \c namespace keyword.
    SourceLocation getNamespaceKeyLocation() const { return NamespaceLoc; }
  
    /// \brief Returns the location of this using declaration's identifier.
    SourceLocation getIdentLocation() const { return getLocation(); }
  
    static UsingDirectiveDecl *Create(ASTContext &C, DeclContext *DC,
                                      SourceLocation UsingLoc,
                                      SourceLocation NamespaceLoc,
                                      NestedNameSpecifierLoc QualifierLoc,
                                      SourceLocation IdentLoc,
                                      NamedDecl *Nominated,
                                      DeclContext *CommonAncestor);
    static UsingDirectiveDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    SourceRange getSourceRange() const override LLVM_READONLY {
      return SourceRange(UsingLoc, getLocation());
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == UsingDirective; }
  
    // Friend for getUsingDirectiveName.
    friend class DeclContext;
  
    friend class ASTDeclReader;
  };
  
  /// \brief Represents a C++ namespace alias.
  ///
  /// For example:
  ///
  /// \code
  /// namespace Foo = Bar;
  /// \endcode
  class NamespaceAliasDecl : public NamedDecl,
                             public Redeclarable<NamespaceAliasDecl> {
    void anchor() override;
  
    /// \brief The location of the \c namespace keyword.
    SourceLocation NamespaceLoc;
  
    /// \brief The location of the namespace's identifier.
    ///
    /// This is accessed by TargetNameLoc.
    SourceLocation IdentLoc;
  
    /// \brief The nested-name-specifier that precedes the namespace.
    NestedNameSpecifierLoc QualifierLoc;
  
    /// \brief The Decl that this alias points to, either a NamespaceDecl or
    /// a NamespaceAliasDecl.
    NamedDecl *Namespace;
  
    NamespaceAliasDecl(ASTContext &C, DeclContext *DC,
                       SourceLocation NamespaceLoc, SourceLocation AliasLoc,
                       IdentifierInfo *Alias, NestedNameSpecifierLoc QualifierLoc,
                       SourceLocation IdentLoc, NamedDecl *Namespace)
        : NamedDecl(NamespaceAlias, DC, AliasLoc, Alias), redeclarable_base(C),
          NamespaceLoc(NamespaceLoc), IdentLoc(IdentLoc),
          QualifierLoc(QualifierLoc), Namespace(Namespace) {}
  
    typedef Redeclarable<NamespaceAliasDecl> redeclarable_base;
    NamespaceAliasDecl *getNextRedeclarationImpl() override;
    NamespaceAliasDecl *getPreviousDeclImpl() override;
    NamespaceAliasDecl *getMostRecentDeclImpl() override;
  
    friend class ASTDeclReader;
  
  public:
    static NamespaceAliasDecl *Create(ASTContext &C, DeclContext *DC,
                                      SourceLocation NamespaceLoc,
                                      SourceLocation AliasLoc,
                                      IdentifierInfo *Alias,
                                      NestedNameSpecifierLoc QualifierLoc,
                                      SourceLocation IdentLoc,
                                      NamedDecl *Namespace);
  
    static NamespaceAliasDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    typedef redeclarable_base::redecl_range redecl_range;
    typedef redeclarable_base::redecl_iterator redecl_iterator;
    using redeclarable_base::redecls_begin;
    using redeclarable_base::redecls_end;
    using redeclarable_base::redecls;
    using redeclarable_base::getPreviousDecl;
    using redeclarable_base::getMostRecentDecl;
  
    NamespaceAliasDecl *getCanonicalDecl() override {
      return getFirstDecl();
    }
    const NamespaceAliasDecl *getCanonicalDecl() const {
      return getFirstDecl();
    }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the
    /// name of the namespace, with source-location information.
    NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the
    /// name of the namespace.
    NestedNameSpecifier *getQualifier() const {
      return QualifierLoc.getNestedNameSpecifier();
    }
  
    /// \brief Retrieve the namespace declaration aliased by this directive.
    NamespaceDecl *getNamespace() {
      if (NamespaceAliasDecl *AD = dyn_cast<NamespaceAliasDecl>(Namespace))
        return AD->getNamespace();
  
      return cast<NamespaceDecl>(Namespace);
    }
  
    const NamespaceDecl *getNamespace() const {
      return const_cast<NamespaceAliasDecl*>(this)->getNamespace();
    }
  
    /// Returns the location of the alias name, i.e. 'foo' in
    /// "namespace foo = ns::bar;".
    SourceLocation getAliasLoc() const { return getLocation(); }
  
    /// Returns the location of the \c namespace keyword.
    SourceLocation getNamespaceLoc() const { return NamespaceLoc; }
  
    /// Returns the location of the identifier in the named namespace.
    SourceLocation getTargetNameLoc() const { return IdentLoc; }
  
    /// \brief Retrieve the namespace that this alias refers to, which
    /// may either be a NamespaceDecl or a NamespaceAliasDecl.
    NamedDecl *getAliasedNamespace() const { return Namespace; }
  
    SourceRange getSourceRange() const override LLVM_READONLY {
      return SourceRange(NamespaceLoc, IdentLoc);
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == NamespaceAlias; }
  };
  
  /// \brief Represents a shadow declaration introduced into a scope by a
  /// (resolved) using declaration.
  ///
  /// For example,
  /// \code
  /// namespace A {
  ///   void foo();
  /// }
  /// namespace B {
  ///   using A::foo; // <- a UsingDecl
  ///                 // Also creates a UsingShadowDecl for A::foo() in B
  /// }
  /// \endcode
  class UsingShadowDecl : public NamedDecl, public Redeclarable<UsingShadowDecl> {
    void anchor() override;
  
    /// The referenced declaration.
    NamedDecl *Underlying;
  
    /// \brief The using declaration which introduced this decl or the next using
    /// shadow declaration contained in the aforementioned using declaration.
    NamedDecl *UsingOrNextShadow;
    friend class UsingDecl;
  
    typedef Redeclarable<UsingShadowDecl> redeclarable_base;
    UsingShadowDecl *getNextRedeclarationImpl() override {
      return getNextRedeclaration();
    }
    UsingShadowDecl *getPreviousDeclImpl() override {
      return getPreviousDecl();
    }
    UsingShadowDecl *getMostRecentDeclImpl() override {
      return getMostRecentDecl();
    }
  
  protected:
    UsingShadowDecl(Kind K, ASTContext &C, DeclContext *DC, SourceLocation Loc,
                    UsingDecl *Using, NamedDecl *Target);
    UsingShadowDecl(Kind K, ASTContext &C, EmptyShell);
  
  public:
    static UsingShadowDecl *Create(ASTContext &C, DeclContext *DC,
                                   SourceLocation Loc, UsingDecl *Using,
                                   NamedDecl *Target) {
      return new (C, DC) UsingShadowDecl(UsingShadow, C, DC, Loc, Using, Target);
    }
  
    static UsingShadowDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    typedef redeclarable_base::redecl_range redecl_range;
    typedef redeclarable_base::redecl_iterator redecl_iterator;
    using redeclarable_base::redecls_begin;
    using redeclarable_base::redecls_end;
    using redeclarable_base::redecls;
    using redeclarable_base::getPreviousDecl;
    using redeclarable_base::getMostRecentDecl;
    using redeclarable_base::isFirstDecl;
  
    UsingShadowDecl *getCanonicalDecl() override {
      return getFirstDecl();
    }
    const UsingShadowDecl *getCanonicalDecl() const {
      return getFirstDecl();
    }
  
    /// \brief Gets the underlying declaration which has been brought into the
    /// local scope.
    NamedDecl *getTargetDecl() const { return Underlying; }
  
    /// \brief Sets the underlying declaration which has been brought into the
    /// local scope.
    void setTargetDecl(NamedDecl* ND) {
      assert(ND && "Target decl is null!");
      Underlying = ND;
      IdentifierNamespace = ND->getIdentifierNamespace();
    }
  
    /// \brief Gets the using declaration to which this declaration is tied.
    UsingDecl *getUsingDecl() const;
  
    /// \brief The next using shadow declaration contained in the shadow decl
    /// chain of the using declaration which introduced this decl.
    UsingShadowDecl *getNextUsingShadowDecl() const {
      return dyn_cast_or_null<UsingShadowDecl>(UsingOrNextShadow);
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) {
      return K == Decl::UsingShadow || K == Decl::ConstructorUsingShadow;
    }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
  };
  
  /// \brief Represents a shadow constructor declaration introduced into a
  /// class by a C++11 using-declaration that names a constructor.
  ///
  /// For example:
  /// \code
  /// struct Base { Base(int); };
  /// struct Derived {
  ///    using Base::Base; // creates a UsingDecl and a ConstructorUsingShadowDecl
  /// };
  /// \endcode
  class ConstructorUsingShadowDecl final : public UsingShadowDecl {
    void anchor() override;
  
    /// \brief If this constructor using declaration inherted the constructor
    /// from an indirect base class, this is the ConstructorUsingShadowDecl
    /// in the named direct base class from which the declaration was inherited.
    ConstructorUsingShadowDecl *NominatedBaseClassShadowDecl;
  
    /// \brief If this constructor using declaration inherted the constructor
    /// from an indirect base class, this is the ConstructorUsingShadowDecl
    /// that will be used to construct the unique direct or virtual base class
    /// that receives the constructor arguments.
    ConstructorUsingShadowDecl *ConstructedBaseClassShadowDecl;
  
    /// \brief \c true if the constructor ultimately named by this using shadow
    /// declaration is within a virtual base class subobject of the class that
    /// contains this declaration.
    unsigned IsVirtual : 1;
  
    ConstructorUsingShadowDecl(ASTContext &C, DeclContext *DC, SourceLocation Loc,
                               UsingDecl *Using, NamedDecl *Target,
                               bool TargetInVirtualBase)
        : UsingShadowDecl(ConstructorUsingShadow, C, DC, Loc, Using,
                          Target->getUnderlyingDecl()),
          NominatedBaseClassShadowDecl(
              dyn_cast<ConstructorUsingShadowDecl>(Target)),
          ConstructedBaseClassShadowDecl(NominatedBaseClassShadowDecl),
          IsVirtual(TargetInVirtualBase) {
      // If we found a constructor for a non-virtual base class, but it chains to
      // a constructor for a virtual base, we should directly call the virtual
      // base constructor instead.
      // FIXME: This logic belongs in Sema.
      if (!TargetInVirtualBase && NominatedBaseClassShadowDecl &&
          NominatedBaseClassShadowDecl->constructsVirtualBase()) {
        ConstructedBaseClassShadowDecl =
            NominatedBaseClassShadowDecl->ConstructedBaseClassShadowDecl;
        IsVirtual = true;
      }
    }
    ConstructorUsingShadowDecl(ASTContext &C, EmptyShell Empty)
        : UsingShadowDecl(ConstructorUsingShadow, C, Empty) {}
  
  public:
    static ConstructorUsingShadowDecl *Create(ASTContext &C, DeclContext *DC,
                                              SourceLocation Loc,
                                              UsingDecl *Using, NamedDecl *Target,
                                              bool IsVirtual);
    static ConstructorUsingShadowDecl *CreateDeserialized(ASTContext &C,
                                                          unsigned ID);
  
    /// Returns the parent of this using shadow declaration, which
    /// is the class in which this is declared.
    //@{
    const CXXRecordDecl *getParent() const {
      return cast<CXXRecordDecl>(getDeclContext());
    }
    CXXRecordDecl *getParent() {
      return cast<CXXRecordDecl>(getDeclContext());
    }
    //@}
  
    /// \brief Get the inheriting constructor declaration for the direct base
    /// class from which this using shadow declaration was inherited, if there is
    /// one. This can be different for each redeclaration of the same shadow decl.
    ConstructorUsingShadowDecl *getNominatedBaseClassShadowDecl() const {
      return NominatedBaseClassShadowDecl;
    }
  
    /// \brief Get the inheriting constructor declaration for the base class
    /// for which we don't have an explicit initializer, if there is one.
    ConstructorUsingShadowDecl *getConstructedBaseClassShadowDecl() const {
      return ConstructedBaseClassShadowDecl;
    }
  
    /// \brief Get the base class that was named in the using declaration. This
    /// can be different for each redeclaration of this same shadow decl.
    CXXRecordDecl *getNominatedBaseClass() const;
  
    /// \brief Get the base class whose constructor or constructor shadow
    /// declaration is passed the constructor arguments.
    CXXRecordDecl *getConstructedBaseClass() const {
      return cast<CXXRecordDecl>((ConstructedBaseClassShadowDecl
                                      ? ConstructedBaseClassShadowDecl
                                      : getTargetDecl())
                                     ->getDeclContext());
    }
  
    /// \brief Returns \c true if the constructed base class is a virtual base
    /// class subobject of this declaration's class.
    bool constructsVirtualBase() const {
      return IsVirtual;
    }
  
    /// \brief Get the constructor or constructor template in the derived class
    /// correspnding to this using shadow declaration, if it has been implicitly
    /// declared already.
    CXXConstructorDecl *getConstructor() const;
    void setConstructor(NamedDecl *Ctor);
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == ConstructorUsingShadow; }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
  };
  
  /// \brief Represents a C++ using-declaration.
  ///
  /// For example:
  /// \code
  ///    using someNameSpace::someIdentifier;
  /// \endcode
  class UsingDecl : public NamedDecl, public Mergeable<UsingDecl> {
    void anchor() override;
  
    /// \brief The source location of the 'using' keyword itself.
    SourceLocation UsingLocation;
  
    /// \brief The nested-name-specifier that precedes the name.
    NestedNameSpecifierLoc QualifierLoc;
  
    /// \brief Provides source/type location info for the declaration name
    /// embedded in the ValueDecl base class.
    DeclarationNameLoc DNLoc;
  
    /// \brief The first shadow declaration of the shadow decl chain associated
    /// with this using declaration.
    ///
    /// The bool member of the pair store whether this decl has the \c typename
    /// keyword.
    llvm::PointerIntPair<UsingShadowDecl *, 1, bool> FirstUsingShadow;
  
    UsingDecl(DeclContext *DC, SourceLocation UL,
              NestedNameSpecifierLoc QualifierLoc,
              const DeclarationNameInfo &NameInfo, bool HasTypenameKeyword)
      : NamedDecl(Using, DC, NameInfo.getLoc(), NameInfo.getName()),
        UsingLocation(UL), QualifierLoc(QualifierLoc),
        DNLoc(NameInfo.getInfo()), FirstUsingShadow(nullptr, HasTypenameKeyword) {
    }
  
  public:
    /// \brief Return the source location of the 'using' keyword.
    SourceLocation getUsingLoc() const { return UsingLocation; }
  
    /// \brief Set the source location of the 'using' keyword.
    void setUsingLoc(SourceLocation L) { UsingLocation = L; }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the name,
    /// with source-location information.
    NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the name.
    NestedNameSpecifier *getQualifier() const {
      return QualifierLoc.getNestedNameSpecifier();
    }
  
    DeclarationNameInfo getNameInfo() const {
      return DeclarationNameInfo(getDeclName(), getLocation(), DNLoc);
    }
  
    /// \brief Return true if it is a C++03 access declaration (no 'using').
    bool isAccessDeclaration() const { return UsingLocation.isInvalid(); }
  
    /// \brief Return true if the using declaration has 'typename'.
    bool hasTypename() const { return FirstUsingShadow.getInt(); }
  
    /// \brief Sets whether the using declaration has 'typename'.
    void setTypename(bool TN) { FirstUsingShadow.setInt(TN); }
  
    /// \brief Iterates through the using shadow declarations associated with
    /// this using declaration.
    class shadow_iterator {
      /// \brief The current using shadow declaration.
      UsingShadowDecl *Current;
  
    public:
      typedef UsingShadowDecl*          value_type;
      typedef UsingShadowDecl*          reference;
      typedef UsingShadowDecl*          pointer;
      typedef std::forward_iterator_tag iterator_category;
      typedef std::ptrdiff_t            difference_type;
  
      shadow_iterator() : Current(nullptr) { }
      explicit shadow_iterator(UsingShadowDecl *C) : Current(C) { }
  
      reference operator*() const { return Current; }
      pointer operator->() const { return Current; }
  
      shadow_iterator& operator++() {
        Current = Current->getNextUsingShadowDecl();
        return *this;
      }
  
      shadow_iterator operator++(int) {
        shadow_iterator tmp(*this);
        ++(*this);
        return tmp;
      }
  
      friend bool operator==(shadow_iterator x, shadow_iterator y) {
        return x.Current == y.Current;
      }
      friend bool operator!=(shadow_iterator x, shadow_iterator y) {
        return x.Current != y.Current;
      }
    };
  
    typedef llvm::iterator_range<shadow_iterator> shadow_range;
  
    shadow_range shadows() const {
      return shadow_range(shadow_begin(), shadow_end());
    }
    shadow_iterator shadow_begin() const {
      return shadow_iterator(FirstUsingShadow.getPointer());
    }
    shadow_iterator shadow_end() const { return shadow_iterator(); }
  
    /// \brief Return the number of shadowed declarations associated with this
    /// using declaration.
    unsigned shadow_size() const {
      return std::distance(shadow_begin(), shadow_end());
    }
  
    void addShadowDecl(UsingShadowDecl *S);
    void removeShadowDecl(UsingShadowDecl *S);
  
    static UsingDecl *Create(ASTContext &C, DeclContext *DC,
                             SourceLocation UsingL,
                             NestedNameSpecifierLoc QualifierLoc,
                             const DeclarationNameInfo &NameInfo,
                             bool HasTypenameKeyword);
  
    static UsingDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    SourceRange getSourceRange() const override LLVM_READONLY;
  
    /// Retrieves the canonical declaration of this declaration.
    UsingDecl *getCanonicalDecl() override { return getFirstDecl(); }
    const UsingDecl *getCanonicalDecl() const { return getFirstDecl(); }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == Using; }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
  };
  
  /// \brief Represents a dependent using declaration which was not marked with
  /// \c typename.
  ///
  /// Unlike non-dependent using declarations, these *only* bring through
  /// non-types; otherwise they would break two-phase lookup.
  ///
  /// \code
  /// template \<class T> class A : public Base<T> {
  ///   using Base<T>::foo;
  /// };
  /// \endcode
  class UnresolvedUsingValueDecl : public ValueDecl,
                                   public Mergeable<UnresolvedUsingValueDecl> {
    void anchor() override;
  
    /// \brief The source location of the 'using' keyword
    SourceLocation UsingLocation;
  
    /// \brief The nested-name-specifier that precedes the name.
    NestedNameSpecifierLoc QualifierLoc;
  
    /// \brief Provides source/type location info for the declaration name
    /// embedded in the ValueDecl base class.
    DeclarationNameLoc DNLoc;
  
    UnresolvedUsingValueDecl(DeclContext *DC, QualType Ty,
                             SourceLocation UsingLoc,
                             NestedNameSpecifierLoc QualifierLoc,
                             const DeclarationNameInfo &NameInfo)
      : ValueDecl(UnresolvedUsingValue, DC,
                  NameInfo.getLoc(), NameInfo.getName(), Ty),
        UsingLocation(UsingLoc), QualifierLoc(QualifierLoc),
        DNLoc(NameInfo.getInfo())
    { }
  
  public:
    /// \brief Returns the source location of the 'using' keyword.
    SourceLocation getUsingLoc() const { return UsingLocation; }
  
    /// \brief Set the source location of the 'using' keyword.
    void setUsingLoc(SourceLocation L) { UsingLocation = L; }
  
    /// \brief Return true if it is a C++03 access declaration (no 'using').
    bool isAccessDeclaration() const { return UsingLocation.isInvalid(); }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the name,
    /// with source-location information.
    NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the name.
    NestedNameSpecifier *getQualifier() const {
      return QualifierLoc.getNestedNameSpecifier();
    }
  
    DeclarationNameInfo getNameInfo() const {
      return DeclarationNameInfo(getDeclName(), getLocation(), DNLoc);
    }
  
    static UnresolvedUsingValueDecl *
      Create(ASTContext &C, DeclContext *DC, SourceLocation UsingLoc,
             NestedNameSpecifierLoc QualifierLoc,
             const DeclarationNameInfo &NameInfo);
  
    static UnresolvedUsingValueDecl *
    CreateDeserialized(ASTContext &C, unsigned ID);
  
    SourceRange getSourceRange() const override LLVM_READONLY;
  
    /// Retrieves the canonical declaration of this declaration.
    UnresolvedUsingValueDecl *getCanonicalDecl() override {
      return getFirstDecl();
    }
    const UnresolvedUsingValueDecl *getCanonicalDecl() const {
      return getFirstDecl();
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == UnresolvedUsingValue; }
  
    friend class ASTDeclReader;
    friend class ASTDeclWriter;
  };
  
  /// \brief Represents a dependent using declaration which was marked with
  /// \c typename.
  ///
  /// \code
  /// template \<class T> class A : public Base<T> {
  ///   using typename Base<T>::foo;
  /// };
  /// \endcode
  ///
  /// The type associated with an unresolved using typename decl is
  /// currently always a typename type.
  class UnresolvedUsingTypenameDecl
      : public TypeDecl,
        public Mergeable<UnresolvedUsingTypenameDecl> {
    void anchor() override;
  
    /// \brief The source location of the 'typename' keyword
    SourceLocation TypenameLocation;
  
    /// \brief The nested-name-specifier that precedes the name.
    NestedNameSpecifierLoc QualifierLoc;
  
    UnresolvedUsingTypenameDecl(DeclContext *DC, SourceLocation UsingLoc,
                                SourceLocation TypenameLoc,
                                NestedNameSpecifierLoc QualifierLoc,
                                SourceLocation TargetNameLoc,
                                IdentifierInfo *TargetName)
      : TypeDecl(UnresolvedUsingTypename, DC, TargetNameLoc, TargetName,
                 UsingLoc),
        TypenameLocation(TypenameLoc), QualifierLoc(QualifierLoc) { }
  
    friend class ASTDeclReader;
  
  public:
    /// \brief Returns the source location of the 'using' keyword.
    SourceLocation getUsingLoc() const { return getLocStart(); }
  
    /// \brief Returns the source location of the 'typename' keyword.
    SourceLocation getTypenameLoc() const { return TypenameLocation; }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the name,
    /// with source-location information.
    NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
  
    /// \brief Retrieve the nested-name-specifier that qualifies the name.
    NestedNameSpecifier *getQualifier() const {
      return QualifierLoc.getNestedNameSpecifier();
    }
  
    static UnresolvedUsingTypenameDecl *
      Create(ASTContext &C, DeclContext *DC, SourceLocation UsingLoc,
             SourceLocation TypenameLoc, NestedNameSpecifierLoc QualifierLoc,
             SourceLocation TargetNameLoc, DeclarationName TargetName);
  
    static UnresolvedUsingTypenameDecl *
    CreateDeserialized(ASTContext &C, unsigned ID);
  
    /// Retrieves the canonical declaration of this declaration.
    UnresolvedUsingTypenameDecl *getCanonicalDecl() override {
      return getFirstDecl();
    }
    const UnresolvedUsingTypenameDecl *getCanonicalDecl() const {
      return getFirstDecl();
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == UnresolvedUsingTypename; }
  };
  
  /// \brief Represents a C++11 static_assert declaration.
  class StaticAssertDecl : public Decl {
    virtual void anchor();
    llvm::PointerIntPair<Expr *, 1, bool> AssertExprAndFailed;
    StringLiteral *Message;
    SourceLocation RParenLoc;
  
    StaticAssertDecl(DeclContext *DC, SourceLocation StaticAssertLoc,
                     Expr *AssertExpr, StringLiteral *Message,
                     SourceLocation RParenLoc, bool Failed)
      : Decl(StaticAssert, DC, StaticAssertLoc),
        AssertExprAndFailed(AssertExpr, Failed), Message(Message),
        RParenLoc(RParenLoc) { }
  
  public:
    static StaticAssertDecl *Create(ASTContext &C, DeclContext *DC,
                                    SourceLocation StaticAssertLoc,
                                    Expr *AssertExpr, StringLiteral *Message,
                                    SourceLocation RParenLoc, bool Failed);
    static StaticAssertDecl *CreateDeserialized(ASTContext &C, unsigned ID);
    
    Expr *getAssertExpr() { return AssertExprAndFailed.getPointer(); }
    const Expr *getAssertExpr() const { return AssertExprAndFailed.getPointer(); }
  
    StringLiteral *getMessage() { return Message; }
    const StringLiteral *getMessage() const { return Message; }
  
    bool isFailed() const { return AssertExprAndFailed.getInt(); }
  
    SourceLocation getRParenLoc() const { return RParenLoc; }
  
    SourceRange getSourceRange() const override LLVM_READONLY {
      return SourceRange(getLocation(), getRParenLoc());
    }
  
    static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    static bool classofKind(Kind K) { return K == StaticAssert; }
  
    friend class ASTDeclReader;
  };
  
  /// An instance of this class represents the declaration of a property
  /// member.  This is a Microsoft extension to C++, first introduced in
  /// Visual Studio .NET 2003 as a parallel to similar features in C#
  /// and Managed C++.
  ///
  /// A property must always be a non-static class member.
  ///
  /// A property member superficially resembles a non-static data
  /// member, except preceded by a property attribute:
  ///   __declspec(property(get=GetX, put=PutX)) int x;
  /// Either (but not both) of the 'get' and 'put' names may be omitted.
  ///
  /// A reference to a property is always an lvalue.  If the lvalue
  /// undergoes lvalue-to-rvalue conversion, then a getter name is
  /// required, and that member is called with no arguments.
  /// If the lvalue is assigned into, then a setter name is required,
  /// and that member is called with one argument, the value assigned.
  /// Both operations are potentially overloaded.  Compound assignments
  /// are permitted, as are the increment and decrement operators.
  ///
  /// The getter and putter methods are permitted to be overloaded,
  /// although their return and parameter types are subject to certain
  /// restrictions according to the type of the property.
  ///
  /// A property declared using an incomplete array type may
  /// additionally be subscripted, adding extra parameters to the getter
  /// and putter methods.
  class MSPropertyDecl : public DeclaratorDecl {
    IdentifierInfo *GetterId, *SetterId;
  
    MSPropertyDecl(DeclContext *DC, SourceLocation L, DeclarationName N,
                   QualType T, TypeSourceInfo *TInfo, SourceLocation StartL,
                   IdentifierInfo *Getter, IdentifierInfo *Setter)
        : DeclaratorDecl(MSProperty, DC, L, N, T, TInfo, StartL),
          GetterId(Getter), SetterId(Setter) {}
  
  public:
    static MSPropertyDecl *Create(ASTContext &C, DeclContext *DC,
                                  SourceLocation L, DeclarationName N, QualType T,
                                  TypeSourceInfo *TInfo, SourceLocation StartL,
                                  IdentifierInfo *Getter, IdentifierInfo *Setter);
    static MSPropertyDecl *CreateDeserialized(ASTContext &C, unsigned ID);
  
    static bool classof(const Decl *D) { return D->getKind() == MSProperty; }
  
    bool hasGetter() const { return GetterId != nullptr; }
    IdentifierInfo* getGetterId() const { return GetterId; }
    bool hasSetter() const { return SetterId != nullptr; }
    IdentifierInfo* getSetterId() const { return SetterId; }
  
    friend class ASTDeclReader;
  };
  
  /// Insertion operator for diagnostics.  This allows sending an AccessSpecifier
  /// into a diagnostic with <<.
  const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
                                      AccessSpecifier AS);
  
  const PartialDiagnostic &operator<<(const PartialDiagnostic &DB,
                                      AccessSpecifier AS);
  
  } // end namespace clang
  
  #endif
  