text: //===--- RecursiveASTVisitor.h - Recursive AST Visitor ----------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  //  This file defines the RecursiveASTVisitor interface, which recursively
  //  traverses the entire AST.
  //
  //===----------------------------------------------------------------------===//
  #ifndef LLVM_CLANG_AST_RECURSIVEASTVISITOR_H
  #define LLVM_CLANG_AST_RECURSIVEASTVISITOR_H
  
  #include "clang/AST/Attr.h"
  #include "clang/AST/Decl.h"
  #include "clang/AST/DeclarationName.h"
  #include "clang/AST/DeclBase.h"
  #include "clang/AST/DeclCXX.h"
  #include "clang/AST/DeclFriend.h"
  #include "clang/AST/DeclObjC.h"
  #include "clang/AST/DeclOpenMP.h"
  #include "clang/AST/DeclTemplate.h"
  #include "clang/AST/Expr.h"
  #include "clang/AST/ExprCXX.h"
  #include "clang/AST/ExprObjC.h"
  #include "clang/AST/ExprOpenMP.h"
  #include "clang/AST/LambdaCapture.h"
  #include "clang/AST/NestedNameSpecifier.h"
  #include "clang/AST/OpenMPClause.h"
  #include "clang/AST/Stmt.h"
  #include "clang/AST/StmtCXX.h"
  #include "clang/AST/StmtObjC.h"
  #include "clang/AST/StmtOpenMP.h"
  #include "clang/AST/TemplateBase.h"
  #include "clang/AST/TemplateName.h"
  #include "clang/AST/Type.h"
  #include "clang/AST/TypeLoc.h"
  #include "clang/Basic/LLVM.h"
  #include "clang/Basic/OpenMPKinds.h"
  #include "clang/Basic/Specifiers.h"
  #include "llvm/ADT/PointerIntPair.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/Support/Casting.h"
  #include <algorithm>
  #include <cstddef>
  #include <type_traits>
  
  // The following three macros are used for meta programming.  The code
  // using them is responsible for defining macro OPERATOR().
  
  // All unary operators.
  #define UNARYOP_LIST()                                                         \
    OPERATOR(PostInc) OPERATOR(PostDec) OPERATOR(PreInc) OPERATOR(PreDec)        \
        OPERATOR(AddrOf) OPERATOR(Deref) OPERATOR(Plus) OPERATOR(Minus)          \
        OPERATOR(Not) OPERATOR(LNot) OPERATOR(Real) OPERATOR(Imag)               \
        OPERATOR(Extension) OPERATOR(Coawait)
  
  // All binary operators (excluding compound assign operators).
  #define BINOP_LIST()                                                           \
    OPERATOR(PtrMemD) OPERATOR(PtrMemI) OPERATOR(Mul) OPERATOR(Div)              \
        OPERATOR(Rem) OPERATOR(Add) OPERATOR(Sub) OPERATOR(Shl) OPERATOR(Shr)    \
        OPERATOR(LT) OPERATOR(GT) OPERATOR(LE) OPERATOR(GE) OPERATOR(EQ)         \
        OPERATOR(NE) OPERATOR(Cmp) OPERATOR(And) OPERATOR(Xor) OPERATOR(Or)      \
        OPERATOR(LAnd) OPERATOR(LOr) OPERATOR(Assign) OPERATOR(Comma)
  
  // All compound assign operators.
  #define CAO_LIST()                                                             \
    OPERATOR(Mul) OPERATOR(Div) OPERATOR(Rem) OPERATOR(Add) OPERATOR(Sub)        \
        OPERATOR(Shl) OPERATOR(Shr) OPERATOR(And) OPERATOR(Or) OPERATOR(Xor)
  
  namespace clang {
  
  // A helper macro to implement short-circuiting when recursing.  It
  // invokes CALL_EXPR, which must be a method call, on the derived
  // object (s.t. a user of RecursiveASTVisitor can override the method
  // in CALL_EXPR).
  #define TRY_TO(CALL_EXPR)                                                      \
    do {                                                                         \
      if (!getDerived().CALL_EXPR)                                               \
        return false;                                                            \
    } while (false)
  
  /// A class that does preorder or postorder
  /// depth-first traversal on the entire Clang AST and visits each node.
  ///
  /// This class performs three distinct tasks:
  ///   1. traverse the AST (i.e. go to each node);
  ///   2. at a given node, walk up the class hierarchy, starting from
  ///      the node's dynamic type, until the top-most class (e.g. Stmt,
  ///      Decl, or Type) is reached.
  ///   3. given a (node, class) combination, where 'class' is some base
  ///      class of the dynamic type of 'node', call a user-overridable
  ///      function to actually visit the node.
  ///
  /// These tasks are done by three groups of methods, respectively:
  ///   1. TraverseDecl(Decl *x) does task #1.  It is the entry point
  ///      for traversing an AST rooted at x.  This method simply
  ///      dispatches (i.e. forwards) to TraverseFoo(Foo *x) where Foo
  ///      is the dynamic type of *x, which calls WalkUpFromFoo(x) and
  ///      then recursively visits the child nodes of x.
  ///      TraverseStmt(Stmt *x) and TraverseType(QualType x) work
  ///      similarly.
  ///   2. WalkUpFromFoo(Foo *x) does task #2.  It does not try to visit
  ///      any child node of x.  Instead, it first calls WalkUpFromBar(x)
  ///      where Bar is the direct parent class of Foo (unless Foo has
  ///      no parent), and then calls VisitFoo(x) (see the next list item).
  ///   3. VisitFoo(Foo *x) does task #3.
  ///
  /// These three method groups are tiered (Traverse* > WalkUpFrom* >
  /// Visit*).  A method (e.g. Traverse*) may call methods from the same
  /// tier (e.g. other Traverse*) or one tier lower (e.g. WalkUpFrom*).
  /// It may not call methods from a higher tier.
  ///
  /// Note that since WalkUpFromFoo() calls WalkUpFromBar() (where Bar
  /// is Foo's super class) before calling VisitFoo(), the result is
  /// that the Visit*() methods for a given node are called in the
  /// top-down order (e.g. for a node of type NamespaceDecl, the order will
  /// be VisitDecl(), VisitNamedDecl(), and then VisitNamespaceDecl()).
  ///
  /// This scheme guarantees that all Visit*() calls for the same AST
  /// node are grouped together.  In other words, Visit*() methods for
  /// different nodes are never interleaved.
  ///
  /// Clients of this visitor should subclass the visitor (providing
  /// themselves as the template argument, using the curiously recurring
  /// template pattern) and override any of the Traverse*, WalkUpFrom*,
  /// and Visit* methods for declarations, types, statements,
  /// expressions, or other AST nodes where the visitor should customize
  /// behavior.  Most users only need to override Visit*.  Advanced
  /// users may override Traverse* and WalkUpFrom* to implement custom
  /// traversal strategies.  Returning false from one of these overridden
  /// functions will abort the entire traversal.
  ///
  /// By default, this visitor tries to visit every part of the explicit
  /// source code exactly once.  The default policy towards templates
  /// is to descend into the 'pattern' class or function body, not any
  /// explicit or implicit instantiations.  Explicit specializations
  /// are still visited, and the patterns of partial specializations
  /// are visited separately.  This behavior can be changed by
  /// overriding shouldVisitTemplateInstantiations() in the derived class
  /// to return true, in which case all known implicit and explicit
  /// instantiations will be visited at the same time as the pattern
  /// from which they were produced.
  ///
  /// By default, this visitor preorder traverses the AST. If postorder traversal
  /// is needed, the \c shouldTraversePostOrder method needs to be overridden
  /// to return \c true.
  template <typename Derived> class RecursiveASTVisitor {
  public:
    /// A queue used for performing data recursion over statements.
    /// Parameters involving this type are used to implement data
    /// recursion over Stmts and Exprs within this class, and should
    /// typically not be explicitly specified by derived classes.
    /// The bool bit indicates whether the statement has been traversed or not.
    typedef SmallVectorImpl<llvm::PointerIntPair<Stmt *, 1, bool>>
      DataRecursionQueue;
  
    /// Return a reference to the derived class.
    Derived &getDerived() { return *static_cast<Derived *>(this); }
  
    /// Return whether this visitor should recurse into
    /// template instantiations.
    bool shouldVisitTemplateInstantiations() const { return false; }
  
    /// Return whether this visitor should recurse into the types of
    /// TypeLocs.
    bool shouldWalkTypesOfTypeLocs() const { return true; }
  
    /// Return whether this visitor should recurse into implicit
    /// code, e.g., implicit constructors and destructors.
    bool shouldVisitImplicitCode() const { return false; }
  
    /// Return whether this visitor should traverse post-order.
    bool shouldTraversePostOrder() const { return false; }
  
    /// Recursively visits an entire AST, starting from the top-level Decls
    /// in the AST traversal scope (by default, the TranslationUnitDecl).
    /// \returns false if visitation was terminated early.
    bool TraverseAST(ASTContext &AST) {
      for (Decl *D : AST.getTraversalScope())
        if (!getDerived().TraverseDecl(D))
          return false;
      return true;
    }
  
    /// Recursively visit a statement or expression, by
    /// dispatching to Traverse*() based on the argument's dynamic type.
    ///
    /// \returns false if the visitation was terminated early, true
    /// otherwise (including when the argument is nullptr).
    bool TraverseStmt(Stmt *S, DataRecursionQueue *Queue = nullptr);
  
    /// Invoked before visiting a statement or expression via data recursion.
    ///
    /// \returns false to skip visiting the node, true otherwise.
    bool dataTraverseStmtPre(Stmt *S) { return true; }
  
    /// Invoked after visiting a statement or expression via data recursion.
    /// This is not invoked if the previously invoked \c dataTraverseStmtPre
    /// returned false.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool dataTraverseStmtPost(Stmt *S) { return true; }
  
    /// Recursively visit a type, by dispatching to
    /// Traverse*Type() based on the argument's getTypeClass() property.
    ///
    /// \returns false if the visitation was terminated early, true
    /// otherwise (including when the argument is a Null type).
    bool TraverseType(QualType T);
  
    /// Recursively visit a type with location, by dispatching to
    /// Traverse*TypeLoc() based on the argument type's getTypeClass() property.
    ///
    /// \returns false if the visitation was terminated early, true
    /// otherwise (including when the argument is a Null type location).
    bool TraverseTypeLoc(TypeLoc TL);
  
    /// Recursively visit an attribute, by dispatching to
    /// Traverse*Attr() based on the argument's dynamic type.
    ///
    /// \returns false if the visitation was terminated early, true
    /// otherwise (including when the argument is a Null type location).
    bool TraverseAttr(Attr *At);
  
    /// Recursively visit a declaration, by dispatching to
    /// Traverse*Decl() based on the argument's dynamic type.
    ///
    /// \returns false if the visitation was terminated early, true
    /// otherwise (including when the argument is NULL).
    bool TraverseDecl(Decl *D);
  
    /// Recursively visit a C++ nested-name-specifier.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseNestedNameSpecifier(NestedNameSpecifier *NNS);
  
    /// Recursively visit a C++ nested-name-specifier with location
    /// information.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS);
  
    /// Recursively visit a name with its location information.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseDeclarationNameInfo(DeclarationNameInfo NameInfo);
  
    /// Recursively visit a template name and dispatch to the
    /// appropriate method.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseTemplateName(TemplateName Template);
  
    /// Recursively visit a template argument and dispatch to the
    /// appropriate method for the argument type.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    // FIXME: migrate callers to TemplateArgumentLoc instead.
    bool TraverseTemplateArgument(const TemplateArgument &Arg);
  
    /// Recursively visit a template argument location and dispatch to the
    /// appropriate method for the argument type.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseTemplateArgumentLoc(const TemplateArgumentLoc &ArgLoc);
  
    /// Recursively visit a set of template arguments.
    /// This can be overridden by a subclass, but it's not expected that
    /// will be needed -- this visitor always dispatches to another.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    // FIXME: take a TemplateArgumentLoc* (or TemplateArgumentListInfo) instead.
    bool TraverseTemplateArguments(const TemplateArgument *Args,
                                   unsigned NumArgs);
  
    /// Recursively visit a base specifier. This can be overridden by a
    /// subclass.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseCXXBaseSpecifier(const CXXBaseSpecifier &Base);
  
    /// Recursively visit a constructor initializer.  This
    /// automatically dispatches to another visitor for the initializer
    /// expression, but not for the name of the initializer, so may
    /// be overridden for clients that need access to the name.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseConstructorInitializer(CXXCtorInitializer *Init);
  
    /// Recursively visit a lambda capture. \c Init is the expression that
    /// will be used to initialize the capture.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseLambdaCapture(LambdaExpr *LE, const LambdaCapture *C,
                               Expr *Init);
  
    /// Recursively visit the syntactic or semantic form of an
    /// initialization list.
    ///
    /// \returns false if the visitation was terminated early, true otherwise.
    bool TraverseSynOrSemInitListExpr(InitListExpr *S,
                                      DataRecursionQueue *Queue = nullptr);
  
    // ---- Methods on Attrs ----
  
    // Visit an attribute.
    bool VisitAttr(Attr *A) { return true; }
  
  // Declare Traverse* and empty Visit* for all Attr classes.
  #define ATTR_VISITOR_DECLS_ONLY
  #include "clang/AST/AttrVisitor.inc"
  #undef ATTR_VISITOR_DECLS_ONLY
  
  // ---- Methods on Stmts ----
  
    Stmt::child_range getStmtChildren(Stmt *S) { return S->children(); }
  
  private:
    template<typename T, typename U>
    struct has_same_member_pointer_type : std::false_type {};
    template<typename T, typename U, typename R, typename... P>
    struct has_same_member_pointer_type<R (T::*)(P...), R (U::*)(P...)>
        : std::true_type {};
  
    // Traverse the given statement. If the most-derived traverse function takes a
    // data recursion queue, pass it on; otherwise, discard it. Note that the
    // first branch of this conditional must compile whether or not the derived
    // class can take a queue, so if we're taking the second arm, make the first
    // arm call our function rather than the derived class version.
  #define TRAVERSE_STMT_BASE(NAME, CLASS, VAR, QUEUE)                            \
    (has_same_member_pointer_type<decltype(                                      \
                                      &RecursiveASTVisitor::Traverse##NAME),     \
                                  decltype(&Derived::Traverse##NAME)>::value     \
         ? static_cast<typename std::conditional<                                \
               has_same_member_pointer_type<                                     \
                   decltype(&RecursiveASTVisitor::Traverse##NAME),               \
                   decltype(&Derived::Traverse##NAME)>::value,                   \
               Derived &, RecursiveASTVisitor &>::type>(*this)                   \
               .Traverse##NAME(static_cast<CLASS *>(VAR), QUEUE)                 \
         : getDerived().Traverse##NAME(static_cast<CLASS *>(VAR)))
  
  // Try to traverse the given statement, or enqueue it if we're performing data
  // recursion in the middle of traversing another statement. Can only be called
  // from within a DEF_TRAVERSE_STMT body or similar context.
  #define TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S)                                     \
    do {                                                                         \
      if (!TRAVERSE_STMT_BASE(Stmt, Stmt, S, Queue))                             \
        return false;                                                            \
    } while (false)
  
  public:
  // Declare Traverse*() for all concrete Stmt classes.
  #define ABSTRACT_STMT(STMT)
  #define STMT(CLASS, PARENT) \
    bool Traverse##CLASS(CLASS *S, DataRecursionQueue *Queue = nullptr);
  #include "clang/AST/StmtNodes.inc"
    // The above header #undefs ABSTRACT_STMT and STMT upon exit.
  
    // Define WalkUpFrom*() and empty Visit*() for all Stmt classes.
    bool WalkUpFromStmt(Stmt *S) { return getDerived().VisitStmt(S); }
    bool VisitStmt(Stmt *S) { return true; }
  #define STMT(CLASS, PARENT)                                                    \
    bool WalkUpFrom##CLASS(CLASS *S) {                                           \
      TRY_TO(WalkUpFrom##PARENT(S));                                             \
      TRY_TO(Visit##CLASS(S));                                                   \
      return true;                                                               \
    }                                                                            \
    bool Visit##CLASS(CLASS *S) { return true; }
  #include "clang/AST/StmtNodes.inc"
  
  // Define Traverse*(), WalkUpFrom*(), and Visit*() for unary
  // operator methods.  Unary operators are not classes in themselves
  // (they're all opcodes in UnaryOperator) but do have visitors.
  #define OPERATOR(NAME)                                                         \
    bool TraverseUnary##NAME(UnaryOperator *S,                                   \
                             DataRecursionQueue *Queue = nullptr) {              \
      if (!getDerived().shouldTraversePostOrder())                               \
        TRY_TO(WalkUpFromUnary##NAME(S));                                        \
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getSubExpr());                          \
      return true;                                                               \
    }                                                                            \
    bool WalkUpFromUnary##NAME(UnaryOperator *S) {                               \
      TRY_TO(WalkUpFromUnaryOperator(S));                                        \
      TRY_TO(VisitUnary##NAME(S));                                               \
      return true;                                                               \
    }                                                                            \
    bool VisitUnary##NAME(UnaryOperator *S) { return true; }
  
    UNARYOP_LIST()
  #undef OPERATOR
  
  // Define Traverse*(), WalkUpFrom*(), and Visit*() for binary
  // operator methods.  Binary operators are not classes in themselves
  // (they're all opcodes in BinaryOperator) but do have visitors.
  #define GENERAL_BINOP_FALLBACK(NAME, BINOP_TYPE)                               \
    bool TraverseBin##NAME(BINOP_TYPE *S, DataRecursionQueue *Queue = nullptr) { \
      if (!getDerived().shouldTraversePostOrder())                               \
        TRY_TO(WalkUpFromBin##NAME(S));                                          \
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getLHS());                              \
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getRHS());                              \
      return true;                                                               \
    }                                                                            \
    bool WalkUpFromBin##NAME(BINOP_TYPE *S) {                                    \
      TRY_TO(WalkUpFrom##BINOP_TYPE(S));                                         \
      TRY_TO(VisitBin##NAME(S));                                                 \
      return true;                                                               \
    }                                                                            \
    bool VisitBin##NAME(BINOP_TYPE *S) { return true; }
  
  #define OPERATOR(NAME) GENERAL_BINOP_FALLBACK(NAME, BinaryOperator)
    BINOP_LIST()
  #undef OPERATOR
  
  // Define Traverse*(), WalkUpFrom*(), and Visit*() for compound
  // assignment methods.  Compound assignment operators are not
  // classes in themselves (they're all opcodes in
  // CompoundAssignOperator) but do have visitors.
  #define OPERATOR(NAME)                                                         \
    GENERAL_BINOP_FALLBACK(NAME##Assign, CompoundAssignOperator)
  
    CAO_LIST()
  #undef OPERATOR
  #undef GENERAL_BINOP_FALLBACK
  
  // ---- Methods on Types ----
  // FIXME: revamp to take TypeLoc's rather than Types.
  
  // Declare Traverse*() for all concrete Type classes.
  #define ABSTRACT_TYPE(CLASS, BASE)
  #define TYPE(CLASS, BASE) bool Traverse##CLASS##Type(CLASS##Type *T);
  #include "clang/AST/TypeNodes.def"
    // The above header #undefs ABSTRACT_TYPE and TYPE upon exit.
  
    // Define WalkUpFrom*() and empty Visit*() for all Type classes.
    bool WalkUpFromType(Type *T) { return getDerived().VisitType(T); }
    bool VisitType(Type *T) { return true; }
  #define TYPE(CLASS, BASE)                                                      \
    bool WalkUpFrom##CLASS##Type(CLASS##Type *T) {                               \
      TRY_TO(WalkUpFrom##BASE(T));                                               \
      TRY_TO(Visit##CLASS##Type(T));                                             \
      return true;                                                               \
    }                                                                            \
    bool Visit##CLASS##Type(CLASS##Type *T) { return true; }
  #include "clang/AST/TypeNodes.def"
  
  // ---- Methods on TypeLocs ----
  // FIXME: this currently just calls the matching Type methods
  
  // Declare Traverse*() for all concrete TypeLoc classes.
  #define ABSTRACT_TYPELOC(CLASS, BASE)
  #define TYPELOC(CLASS, BASE) bool Traverse##CLASS##TypeLoc(CLASS##TypeLoc TL);
  #include "clang/AST/TypeLocNodes.def"
    // The above header #undefs ABSTRACT_TYPELOC and TYPELOC upon exit.
  
    // Define WalkUpFrom*() and empty Visit*() for all TypeLoc classes.
    bool WalkUpFromTypeLoc(TypeLoc TL) { return getDerived().VisitTypeLoc(TL); }
    bool VisitTypeLoc(TypeLoc TL) { return true; }
  
    // QualifiedTypeLoc and UnqualTypeLoc are not declared in
    // TypeNodes.def and thus need to be handled specially.
    bool WalkUpFromQualifiedTypeLoc(QualifiedTypeLoc TL) {
      return getDerived().VisitUnqualTypeLoc(TL.getUnqualifiedLoc());
    }
    bool VisitQualifiedTypeLoc(QualifiedTypeLoc TL) { return true; }
    bool WalkUpFromUnqualTypeLoc(UnqualTypeLoc TL) {
      return getDerived().VisitUnqualTypeLoc(TL.getUnqualifiedLoc());
    }
    bool VisitUnqualTypeLoc(UnqualTypeLoc TL) { return true; }
  
  // Note that BASE includes trailing 'Type' which CLASS doesn't.
  #define TYPE(CLASS, BASE)                                                      \
    bool WalkUpFrom##CLASS##TypeLoc(CLASS##TypeLoc TL) {                         \
      TRY_TO(WalkUpFrom##BASE##Loc(TL));                                         \
      TRY_TO(Visit##CLASS##TypeLoc(TL));                                         \
      return true;                                                               \
    }                                                                            \
    bool Visit##CLASS##TypeLoc(CLASS##TypeLoc TL) { return true; }
  #include "clang/AST/TypeNodes.def"
  
  // ---- Methods on Decls ----
  
  // Declare Traverse*() for all concrete Decl classes.
  #define ABSTRACT_DECL(DECL)
  #define DECL(CLASS, BASE) bool Traverse##CLASS##Decl(CLASS##Decl *D);
  #include "clang/AST/DeclNodes.inc"
    // The above header #undefs ABSTRACT_DECL and DECL upon exit.
  
    // Define WalkUpFrom*() and empty Visit*() for all Decl classes.
    bool WalkUpFromDecl(Decl *D) { return getDerived().VisitDecl(D); }
    bool VisitDecl(Decl *D) { return true; }
  #define DECL(CLASS, BASE)                                                      \
    bool WalkUpFrom##CLASS##Decl(CLASS##Decl *D) {                               \
      TRY_TO(WalkUpFrom##BASE(D));                                               \
      TRY_TO(Visit##CLASS##Decl(D));                                             \
      return true;                                                               \
    }                                                                            \
    bool Visit##CLASS##Decl(CLASS##Decl *D) { return true; }
  #include "clang/AST/DeclNodes.inc"
  
    bool canIgnoreChildDeclWhileTraversingDeclContext(const Decl *Child);
  
  private:
    // These are helper methods used by more than one Traverse* method.
    bool TraverseTemplateParameterListHelper(TemplateParameterList *TPL);
  
    // Traverses template parameter lists of either a DeclaratorDecl or TagDecl.
    template <typename T>
    bool TraverseDeclTemplateParameterLists(T *D);
  
  #define DEF_TRAVERSE_TMPL_INST(TMPLDECLKIND)                                   \
    bool TraverseTemplateInstantiations(TMPLDECLKIND##TemplateDecl *D);
    DEF_TRAVERSE_TMPL_INST(Class)
    DEF_TRAVERSE_TMPL_INST(Var)
    DEF_TRAVERSE_TMPL_INST(Function)
  #undef DEF_TRAVERSE_TMPL_INST
    bool TraverseTemplateArgumentLocsHelper(const TemplateArgumentLoc *TAL,
                                            unsigned Count);
    bool TraverseArrayTypeLocHelper(ArrayTypeLoc TL);
    bool TraverseRecordHelper(RecordDecl *D);
    bool TraverseCXXRecordHelper(CXXRecordDecl *D);
    bool TraverseDeclaratorHelper(DeclaratorDecl *D);
    bool TraverseDeclContextHelper(DeclContext *DC);
    bool TraverseFunctionHelper(FunctionDecl *D);
    bool TraverseVarHelper(VarDecl *D);
    bool TraverseOMPExecutableDirective(OMPExecutableDirective *S);
    bool TraverseOMPLoopDirective(OMPLoopDirective *S);
    bool TraverseOMPClause(OMPClause *C);
  #define OPENMP_CLAUSE(Name, Class) bool Visit##Class(Class *C);
  #include "clang/Basic/OpenMPKinds.def"
    /// Process clauses with list of variables.
    template <typename T> bool VisitOMPClauseList(T *Node);
    /// Process clauses with pre-initis.
    bool VisitOMPClauseWithPreInit(OMPClauseWithPreInit *Node);
    bool VisitOMPClauseWithPostUpdate(OMPClauseWithPostUpdate *Node);
  
    bool dataTraverseNode(Stmt *S, DataRecursionQueue *Queue);
    bool PostVisitStmt(Stmt *S);
  };
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::dataTraverseNode(Stmt *S,
                                                      DataRecursionQueue *Queue) {
  #define DISPATCH_STMT(NAME, CLASS, VAR)                                        \
    return TRAVERSE_STMT_BASE(NAME, CLASS, VAR, Queue);
  
    // If we have a binary expr, dispatch to the subcode of the binop.  A smart
    // optimizer (e.g. LLVM) will fold this comparison into the switch stmt
    // below.
    if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(S)) {
      switch (BinOp->getOpcode()) {
  #define OPERATOR(NAME)                                                         \
    case BO_##NAME:                                                              \
      DISPATCH_STMT(Bin##NAME, BinaryOperator, S);
  
        BINOP_LIST()
  #undef OPERATOR
  #undef BINOP_LIST
  
  #define OPERATOR(NAME)                                                         \
    case BO_##NAME##Assign:                                                      \
      DISPATCH_STMT(Bin##NAME##Assign, CompoundAssignOperator, S);
  
        CAO_LIST()
  #undef OPERATOR
  #undef CAO_LIST
      }
    } else if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(S)) {
      switch (UnOp->getOpcode()) {
  #define OPERATOR(NAME)                                                         \
    case UO_##NAME:                                                              \
      DISPATCH_STMT(Unary##NAME, UnaryOperator, S);
  
        UNARYOP_LIST()
  #undef OPERATOR
  #undef UNARYOP_LIST
      }
    }
  
    // Top switch stmt: dispatch to TraverseFooStmt for each concrete FooStmt.
    switch (S->getStmtClass()) {
    case Stmt::NoStmtClass:
      break;
  #define ABSTRACT_STMT(STMT)
  #define STMT(CLASS, PARENT)                                                    \
    case Stmt::CLASS##Class:                                                     \
      DISPATCH_STMT(CLASS, CLASS, S);
  #include "clang/AST/StmtNodes.inc"
    }
  
    return true;
  }
  
  #undef DISPATCH_STMT
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::PostVisitStmt(Stmt *S) {
    switch (S->getStmtClass()) {
    case Stmt::NoStmtClass:
      break;
  #define ABSTRACT_STMT(STMT)
  #define STMT(CLASS, PARENT)                                                    \
    case Stmt::CLASS##Class:                                                     \
      TRY_TO(WalkUpFrom##CLASS(static_cast<CLASS *>(S))); break;
  #define INITLISTEXPR(CLASS, PARENT)                                            \
    case Stmt::CLASS##Class:                                                     \
      {                                                                          \
        auto ILE = static_cast<CLASS *>(S);                                      \
        if (auto Syn = ILE->isSemanticForm() ? ILE->getSyntacticForm() : ILE)    \
          TRY_TO(WalkUpFrom##CLASS(Syn));                                        \
        if (auto Sem = ILE->isSemanticForm() ? ILE : ILE->getSemanticForm())     \
          TRY_TO(WalkUpFrom##CLASS(Sem));                                        \
        break;                                                                   \
      }
  #include "clang/AST/StmtNodes.inc"
    }
  
    return true;
  }
  
  #undef DISPATCH_STMT
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseStmt(Stmt *S,
                                                  DataRecursionQueue *Queue) {
    if (!S)
      return true;
  
    if (Queue) {
      Queue->push_back({S, false});
      return true;
    }
  
    SmallVector<llvm::PointerIntPair<Stmt *, 1, bool>, 8> LocalQueue;
    LocalQueue.push_back({S, false});
  
    while (!LocalQueue.empty()) {
      auto &CurrSAndVisited = LocalQueue.back();
      Stmt *CurrS = CurrSAndVisited.getPointer();
      bool Visited = CurrSAndVisited.getInt();
      if (Visited) {
        LocalQueue.pop_back();
        TRY_TO(dataTraverseStmtPost(CurrS));
        if (getDerived().shouldTraversePostOrder()) {
          TRY_TO(PostVisitStmt(CurrS));
        }
        continue;
      }
  
      if (getDerived().dataTraverseStmtPre(CurrS)) {
        CurrSAndVisited.setInt(true);
        size_t N = LocalQueue.size();
        TRY_TO(dataTraverseNode(CurrS, &LocalQueue));
        // Process new children in the order they were added.
        std::reverse(LocalQueue.begin() + N, LocalQueue.end());
      } else {
        LocalQueue.pop_back();
      }
    }
  
    return true;
  }
  
  #define DISPATCH(NAME, CLASS, VAR)                                             \
    return getDerived().Traverse##NAME(static_cast<CLASS *>(VAR))
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseType(QualType T) {
    if (T.isNull())
      return true;
  
    switch (T->getTypeClass()) {
  #define ABSTRACT_TYPE(CLASS, BASE)
  #define TYPE(CLASS, BASE)                                                      \
    case Type::CLASS:                                                            \
      DISPATCH(CLASS##Type, CLASS##Type, const_cast<Type *>(T.getTypePtr()));
  #include "clang/AST/TypeNodes.def"
    }
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTypeLoc(TypeLoc TL) {
    if (TL.isNull())
      return true;
  
    switch (TL.getTypeLocClass()) {
  #define ABSTRACT_TYPELOC(CLASS, BASE)
  #define TYPELOC(CLASS, BASE)                                                   \
    case TypeLoc::CLASS:                                                         \
      return getDerived().Traverse##CLASS##TypeLoc(TL.castAs<CLASS##TypeLoc>());
  #include "clang/AST/TypeLocNodes.def"
    }
  
    return true;
  }
  
  // Define the Traverse*Attr(Attr* A) methods
  #define VISITORCLASS RecursiveASTVisitor
  #include "clang/AST/AttrVisitor.inc"
  #undef VISITORCLASS
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseDecl(Decl *D) {
    if (!D)
      return true;
  
    // As a syntax visitor, by default we want to ignore declarations for
    // implicit declarations (ones not typed explicitly by the user).
    if (!getDerived().shouldVisitImplicitCode() && D->isImplicit())
      return true;
  
    switch (D->getKind()) {
  #define ABSTRACT_DECL(DECL)
  #define DECL(CLASS, BASE)                                                      \
    case Decl::CLASS:                                                            \
      if (!getDerived().Traverse##CLASS##Decl(static_cast<CLASS##Decl *>(D)))    \
        return false;                                                            \
      break;
  #include "clang/AST/DeclNodes.inc"
    }
  
    // Visit any attributes attached to this declaration.
    for (auto *I : D->attrs()) {
      if (!getDerived().TraverseAttr(I))
        return false;
    }
    return true;
  }
  
  #undef DISPATCH
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifier(
      NestedNameSpecifier *NNS) {
    if (!NNS)
      return true;
  
    if (NNS->getPrefix())
      TRY_TO(TraverseNestedNameSpecifier(NNS->getPrefix()));
  
    switch (NNS->getKind()) {
    case NestedNameSpecifier::Identifier:
    case NestedNameSpecifier::Namespace:
    case NestedNameSpecifier::NamespaceAlias:
    case NestedNameSpecifier::Global:
    case NestedNameSpecifier::Super:
      return true;
  
    case NestedNameSpecifier::TypeSpec:
    case NestedNameSpecifier::TypeSpecWithTemplate:
      TRY_TO(TraverseType(QualType(NNS->getAsType(), 0)));
    }
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifierLoc(
      NestedNameSpecifierLoc NNS) {
    if (!NNS)
      return true;
  
    if (NestedNameSpecifierLoc Prefix = NNS.getPrefix())
      TRY_TO(TraverseNestedNameSpecifierLoc(Prefix));
  
    switch (NNS.getNestedNameSpecifier()->getKind()) {
    case NestedNameSpecifier::Identifier:
    case NestedNameSpecifier::Namespace:
    case NestedNameSpecifier::NamespaceAlias:
    case NestedNameSpecifier::Global:
    case NestedNameSpecifier::Super:
      return true;
  
    case NestedNameSpecifier::TypeSpec:
    case NestedNameSpecifier::TypeSpecWithTemplate:
      TRY_TO(TraverseTypeLoc(NNS.getTypeLoc()));
      break;
    }
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseDeclarationNameInfo(
      DeclarationNameInfo NameInfo) {
    switch (NameInfo.getName().getNameKind()) {
    case DeclarationName::CXXConstructorName:
    case DeclarationName::CXXDestructorName:
    case DeclarationName::CXXConversionFunctionName:
      if (TypeSourceInfo *TSInfo = NameInfo.getNamedTypeInfo())
        TRY_TO(TraverseTypeLoc(TSInfo->getTypeLoc()));
      break;
  
    case DeclarationName::CXXDeductionGuideName:
      TRY_TO(TraverseTemplateName(
          TemplateName(NameInfo.getName().getCXXDeductionGuideTemplate())));
      break;
  
    case DeclarationName::Identifier:
    case DeclarationName::ObjCZeroArgSelector:
    case DeclarationName::ObjCOneArgSelector:
    case DeclarationName::ObjCMultiArgSelector:
    case DeclarationName::CXXOperatorName:
    case DeclarationName::CXXLiteralOperatorName:
    case DeclarationName::CXXUsingDirective:
      break;
    }
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateName(TemplateName Template) {
    if (DependentTemplateName *DTN = Template.getAsDependentTemplateName())
      TRY_TO(TraverseNestedNameSpecifier(DTN->getQualifier()));
    else if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
      TRY_TO(TraverseNestedNameSpecifier(QTN->getQualifier()));
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateArgument(
      const TemplateArgument &Arg) {
    switch (Arg.getKind()) {
    case TemplateArgument::Null:
    case TemplateArgument::Declaration:
    case TemplateArgument::Integral:
    case TemplateArgument::NullPtr:
      return true;
  
    case TemplateArgument::Type:
      return getDerived().TraverseType(Arg.getAsType());
  
    case TemplateArgument::Template:
    case TemplateArgument::TemplateExpansion:
      return getDerived().TraverseTemplateName(
          Arg.getAsTemplateOrTemplatePattern());
  
    case TemplateArgument::Expression:
      return getDerived().TraverseStmt(Arg.getAsExpr());
  
    case TemplateArgument::Pack:
      return getDerived().TraverseTemplateArguments(Arg.pack_begin(),
                                                    Arg.pack_size());
    }
  
    return true;
  }
  
  // FIXME: no template name location?
  // FIXME: no source locations for a template argument pack?
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateArgumentLoc(
      const TemplateArgumentLoc &ArgLoc) {
    const TemplateArgument &Arg = ArgLoc.getArgument();
  
    switch (Arg.getKind()) {
    case TemplateArgument::Null:
    case TemplateArgument::Declaration:
    case TemplateArgument::Integral:
    case TemplateArgument::NullPtr:
      return true;
  
    case TemplateArgument::Type: {
      // FIXME: how can TSI ever be NULL?
      if (TypeSourceInfo *TSI = ArgLoc.getTypeSourceInfo())
        return getDerived().TraverseTypeLoc(TSI->getTypeLoc());
      else
        return getDerived().TraverseType(Arg.getAsType());
    }
  
    case TemplateArgument::Template:
    case TemplateArgument::TemplateExpansion:
      if (ArgLoc.getTemplateQualifierLoc())
        TRY_TO(getDerived().TraverseNestedNameSpecifierLoc(
            ArgLoc.getTemplateQualifierLoc()));
      return getDerived().TraverseTemplateName(
          Arg.getAsTemplateOrTemplatePattern());
  
    case TemplateArgument::Expression:
      return getDerived().TraverseStmt(ArgLoc.getSourceExpression());
  
    case TemplateArgument::Pack:
      return getDerived().TraverseTemplateArguments(Arg.pack_begin(),
                                                    Arg.pack_size());
    }
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateArguments(
      const TemplateArgument *Args, unsigned NumArgs) {
    for (unsigned I = 0; I != NumArgs; ++I) {
      TRY_TO(TraverseTemplateArgument(Args[I]));
    }
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseConstructorInitializer(
      CXXCtorInitializer *Init) {
    if (TypeSourceInfo *TInfo = Init->getTypeSourceInfo())
      TRY_TO(TraverseTypeLoc(TInfo->getTypeLoc()));
  
    if (Init->isWritten() || getDerived().shouldVisitImplicitCode())
      TRY_TO(TraverseStmt(Init->getInit()));
  
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::TraverseLambdaCapture(LambdaExpr *LE,
                                                      const LambdaCapture *C,
                                                      Expr *Init) {
    if (LE->isInitCapture(C))
      TRY_TO(TraverseDecl(C->getCapturedVar()));
    else
      TRY_TO(TraverseStmt(Init));
    return true;
  }
  
  // ----------------- Type traversal -----------------
  
  // This macro makes available a variable T, the passed-in type.
  #define DEF_TRAVERSE_TYPE(TYPE, CODE)                                          \
    template <typename Derived>                                                  \
    bool RecursiveASTVisitor<Derived>::Traverse##TYPE(TYPE *T) {                 \
      if (!getDerived().shouldTraversePostOrder())                               \
        TRY_TO(WalkUpFrom##TYPE(T));                                             \
      { CODE; }                                                                  \
      if (getDerived().shouldTraversePostOrder())                                \
        TRY_TO(WalkUpFrom##TYPE(T));                                             \
      return true;                                                               \
    }
  
  DEF_TRAVERSE_TYPE(BuiltinType, {})
  
  DEF_TRAVERSE_TYPE(ComplexType, { TRY_TO(TraverseType(T->getElementType())); })
  
  DEF_TRAVERSE_TYPE(PointerType, { TRY_TO(TraverseType(T->getPointeeType())); })
  
  DEF_TRAVERSE_TYPE(BlockPointerType,
                    { TRY_TO(TraverseType(T->getPointeeType())); })
  
  DEF_TRAVERSE_TYPE(LValueReferenceType,
                    { TRY_TO(TraverseType(T->getPointeeType())); })
  
  DEF_TRAVERSE_TYPE(RValueReferenceType,
                    { TRY_TO(TraverseType(T->getPointeeType())); })
  
  DEF_TRAVERSE_TYPE(MemberPointerType, {
    TRY_TO(TraverseType(QualType(T->getClass(), 0)));
    TRY_TO(TraverseType(T->getPointeeType()));
  })
  
  DEF_TRAVERSE_TYPE(AdjustedType, { TRY_TO(TraverseType(T->getOriginalType())); })
  
  DEF_TRAVERSE_TYPE(DecayedType, { TRY_TO(TraverseType(T->getOriginalType())); })
  
  DEF_TRAVERSE_TYPE(ConstantArrayType,
                    { TRY_TO(TraverseType(T->getElementType())); })
  
  DEF_TRAVERSE_TYPE(IncompleteArrayType,
                    { TRY_TO(TraverseType(T->getElementType())); })
  
  DEF_TRAVERSE_TYPE(VariableArrayType, {
    TRY_TO(TraverseType(T->getElementType()));
    TRY_TO(TraverseStmt(T->getSizeExpr()));
  })
  
  DEF_TRAVERSE_TYPE(DependentSizedArrayType, {
    TRY_TO(TraverseType(T->getElementType()));
    if (T->getSizeExpr())
      TRY_TO(TraverseStmt(T->getSizeExpr()));
  })
  
  DEF_TRAVERSE_TYPE(DependentAddressSpaceType, {
    TRY_TO(TraverseStmt(T->getAddrSpaceExpr()));
    TRY_TO(TraverseType(T->getPointeeType()));
  })
  
  DEF_TRAVERSE_TYPE(DependentVectorType, {
    if (T->getSizeExpr())
      TRY_TO(TraverseStmt(T->getSizeExpr()));
    TRY_TO(TraverseType(T->getElementType()));
  })
  
  DEF_TRAVERSE_TYPE(DependentSizedExtVectorType, {
    if (T->getSizeExpr())
      TRY_TO(TraverseStmt(T->getSizeExpr()));
    TRY_TO(TraverseType(T->getElementType()));
  })
  
  DEF_TRAVERSE_TYPE(VectorType, { TRY_TO(TraverseType(T->getElementType())); })
  
  DEF_TRAVERSE_TYPE(ExtVectorType, { TRY_TO(TraverseType(T->getElementType())); })
  
  DEF_TRAVERSE_TYPE(FunctionNoProtoType,
                    { TRY_TO(TraverseType(T->getReturnType())); })
  
  DEF_TRAVERSE_TYPE(FunctionProtoType, {
    TRY_TO(TraverseType(T->getReturnType()));
  
    for (const auto &A : T->param_types()) {
      TRY_TO(TraverseType(A));
    }
  
    for (const auto &E : T->exceptions()) {
      TRY_TO(TraverseType(E));
    }
  
    if (Expr *NE = T->getNoexceptExpr())
      TRY_TO(TraverseStmt(NE));
  })
  
  DEF_TRAVERSE_TYPE(UnresolvedUsingType, {})
  DEF_TRAVERSE_TYPE(TypedefType, {})
  
  DEF_TRAVERSE_TYPE(TypeOfExprType,
                    { TRY_TO(TraverseStmt(T->getUnderlyingExpr())); })
  
  DEF_TRAVERSE_TYPE(TypeOfType, { TRY_TO(TraverseType(T->getUnderlyingType())); })
  
  DEF_TRAVERSE_TYPE(DecltypeType,
                    { TRY_TO(TraverseStmt(T->getUnderlyingExpr())); })
  
  DEF_TRAVERSE_TYPE(UnaryTransformType, {
    TRY_TO(TraverseType(T->getBaseType()));
    TRY_TO(TraverseType(T->getUnderlyingType()));
  })
  
  DEF_TRAVERSE_TYPE(AutoType, { TRY_TO(TraverseType(T->getDeducedType())); })
  DEF_TRAVERSE_TYPE(DeducedTemplateSpecializationType, {
    TRY_TO(TraverseTemplateName(T->getTemplateName()));
    TRY_TO(TraverseType(T->getDeducedType()));
  })
  
  DEF_TRAVERSE_TYPE(RecordType, {})
  DEF_TRAVERSE_TYPE(EnumType, {})
  DEF_TRAVERSE_TYPE(TemplateTypeParmType, {})
  DEF_TRAVERSE_TYPE(SubstTemplateTypeParmType, {
    TRY_TO(TraverseType(T->getReplacementType()));
  })
  DEF_TRAVERSE_TYPE(SubstTemplateTypeParmPackType, {
    TRY_TO(TraverseTemplateArgument(T->getArgumentPack()));
  })
  
  DEF_TRAVERSE_TYPE(TemplateSpecializationType, {
    TRY_TO(TraverseTemplateName(T->getTemplateName()));
    TRY_TO(TraverseTemplateArguments(T->getArgs(), T->getNumArgs()));
  })
  
  DEF_TRAVERSE_TYPE(InjectedClassNameType, {})
  
  DEF_TRAVERSE_TYPE(AttributedType,
                    { TRY_TO(TraverseType(T->getModifiedType())); })
  
  DEF_TRAVERSE_TYPE(ParenType, { TRY_TO(TraverseType(T->getInnerType())); })
  
  DEF_TRAVERSE_TYPE(ElaboratedType, {
    if (T->getQualifier()) {
      TRY_TO(TraverseNestedNameSpecifier(T->getQualifier()));
    }
    TRY_TO(TraverseType(T->getNamedType()));
  })
  
  DEF_TRAVERSE_TYPE(DependentNameType,
                    { TRY_TO(TraverseNestedNameSpecifier(T->getQualifier())); })
  
  DEF_TRAVERSE_TYPE(DependentTemplateSpecializationType, {
    TRY_TO(TraverseNestedNameSpecifier(T->getQualifier()));
    TRY_TO(TraverseTemplateArguments(T->getArgs(), T->getNumArgs()));
  })
  
  DEF_TRAVERSE_TYPE(PackExpansionType, { TRY_TO(TraverseType(T->getPattern())); })
  
  DEF_TRAVERSE_TYPE(ObjCTypeParamType, {})
  
  DEF_TRAVERSE_TYPE(ObjCInterfaceType, {})
  
  DEF_TRAVERSE_TYPE(ObjCObjectType, {
    // We have to watch out here because an ObjCInterfaceType's base
    // type is itself.
    if (T->getBaseType().getTypePtr() != T)
      TRY_TO(TraverseType(T->getBaseType()));
    for (auto typeArg : T->getTypeArgsAsWritten()) {
      TRY_TO(TraverseType(typeArg));
    }
  })
  
  DEF_TRAVERSE_TYPE(ObjCObjectPointerType,
                    { TRY_TO(TraverseType(T->getPointeeType())); })
  
  DEF_TRAVERSE_TYPE(AtomicType, { TRY_TO(TraverseType(T->getValueType())); })
  
  DEF_TRAVERSE_TYPE(PipeType, { TRY_TO(TraverseType(T->getElementType())); })
  
  #undef DEF_TRAVERSE_TYPE
  
  // ----------------- TypeLoc traversal -----------------
  
  // This macro makes available a variable TL, the passed-in TypeLoc.
  // If requested, it calls WalkUpFrom* for the Type in the given TypeLoc,
  // in addition to WalkUpFrom* for the TypeLoc itself, such that existing
  // clients that override the WalkUpFrom*Type() and/or Visit*Type() methods
  // continue to work.
  #define DEF_TRAVERSE_TYPELOC(TYPE, CODE)                                       \
    template <typename Derived>                                                  \
    bool RecursiveASTVisitor<Derived>::Traverse##TYPE##Loc(TYPE##Loc TL) {       \
      if (getDerived().shouldWalkTypesOfTypeLocs())                              \
        TRY_TO(WalkUpFrom##TYPE(const_cast<TYPE *>(TL.getTypePtr())));           \
      TRY_TO(WalkUpFrom##TYPE##Loc(TL));                                         \
      { CODE; }                                                                  \
      return true;                                                               \
    }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::TraverseQualifiedTypeLoc(QualifiedTypeLoc TL) {
    // Move this over to the 'main' typeloc tree.  Note that this is a
    // move -- we pretend that we were really looking at the unqualified
    // typeloc all along -- rather than a recursion, so we don't follow
    // the normal CRTP plan of going through
    // getDerived().TraverseTypeLoc.  If we did, we'd be traversing
    // twice for the same type (once as a QualifiedTypeLoc version of
    // the type, once as an UnqualifiedTypeLoc version of the type),
    // which in effect means we'd call VisitTypeLoc twice with the
    // 'same' type.  This solves that problem, at the cost of never
    // seeing the qualified version of the type (unless the client
    // subclasses TraverseQualifiedTypeLoc themselves).  It's not a
    // perfect solution.  A perfect solution probably requires making
    // QualifiedTypeLoc a wrapper around TypeLoc -- like QualType is a
    // wrapper around Type* -- rather than being its own class in the
    // type hierarchy.
    return TraverseTypeLoc(TL.getUnqualifiedLoc());
  }
  
  DEF_TRAVERSE_TYPELOC(BuiltinType, {})
  
  // FIXME: ComplexTypeLoc is unfinished
  DEF_TRAVERSE_TYPELOC(ComplexType, {
    TRY_TO(TraverseType(TL.getTypePtr()->getElementType()));
  })
  
  DEF_TRAVERSE_TYPELOC(PointerType,
                       { TRY_TO(TraverseTypeLoc(TL.getPointeeLoc())); })
  
  DEF_TRAVERSE_TYPELOC(BlockPointerType,
                       { TRY_TO(TraverseTypeLoc(TL.getPointeeLoc())); })
  
  DEF_TRAVERSE_TYPELOC(LValueReferenceType,
                       { TRY_TO(TraverseTypeLoc(TL.getPointeeLoc())); })
  
  DEF_TRAVERSE_TYPELOC(RValueReferenceType,
                       { TRY_TO(TraverseTypeLoc(TL.getPointeeLoc())); })
  
  // FIXME: location of base class?
  // We traverse this in the type case as well, but how is it not reached through
  // the pointee type?
  DEF_TRAVERSE_TYPELOC(MemberPointerType, {
    TRY_TO(TraverseType(QualType(TL.getTypePtr()->getClass(), 0)));
    TRY_TO(TraverseTypeLoc(TL.getPointeeLoc()));
  })
  
  DEF_TRAVERSE_TYPELOC(AdjustedType,
                       { TRY_TO(TraverseTypeLoc(TL.getOriginalLoc())); })
  
  DEF_TRAVERSE_TYPELOC(DecayedType,
                       { TRY_TO(TraverseTypeLoc(TL.getOriginalLoc())); })
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseArrayTypeLocHelper(ArrayTypeLoc TL) {
    // This isn't available for ArrayType, but is for the ArrayTypeLoc.
    TRY_TO(TraverseStmt(TL.getSizeExpr()));
    return true;
  }
  
  DEF_TRAVERSE_TYPELOC(ConstantArrayType, {
    TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
    return TraverseArrayTypeLocHelper(TL);
  })
  
  DEF_TRAVERSE_TYPELOC(IncompleteArrayType, {
    TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
    return TraverseArrayTypeLocHelper(TL);
  })
  
  DEF_TRAVERSE_TYPELOC(VariableArrayType, {
    TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
    return TraverseArrayTypeLocHelper(TL);
  })
  
  DEF_TRAVERSE_TYPELOC(DependentSizedArrayType, {
    TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
    return TraverseArrayTypeLocHelper(TL);
  })
  
  DEF_TRAVERSE_TYPELOC(DependentAddressSpaceType, {
    TRY_TO(TraverseStmt(TL.getTypePtr()->getAddrSpaceExpr()));
    TRY_TO(TraverseType(TL.getTypePtr()->getPointeeType()));
  })
  
  // FIXME: order? why not size expr first?
  // FIXME: base VectorTypeLoc is unfinished
  DEF_TRAVERSE_TYPELOC(DependentSizedExtVectorType, {
    if (TL.getTypePtr()->getSizeExpr())
      TRY_TO(TraverseStmt(TL.getTypePtr()->getSizeExpr()));
    TRY_TO(TraverseType(TL.getTypePtr()->getElementType()));
  })
  
  // FIXME: VectorTypeLoc is unfinished
  DEF_TRAVERSE_TYPELOC(VectorType, {
    TRY_TO(TraverseType(TL.getTypePtr()->getElementType()));
  })
  
  DEF_TRAVERSE_TYPELOC(DependentVectorType, {
    if (TL.getTypePtr()->getSizeExpr())
      TRY_TO(TraverseStmt(TL.getTypePtr()->getSizeExpr()));
    TRY_TO(TraverseType(TL.getTypePtr()->getElementType()));
  })
  
  // FIXME: size and attributes
  // FIXME: base VectorTypeLoc is unfinished
  DEF_TRAVERSE_TYPELOC(ExtVectorType, {
    TRY_TO(TraverseType(TL.getTypePtr()->getElementType()));
  })
  
  DEF_TRAVERSE_TYPELOC(FunctionNoProtoType,
                       { TRY_TO(TraverseTypeLoc(TL.getReturnLoc())); })
  
  // FIXME: location of exception specifications (attributes?)
  DEF_TRAVERSE_TYPELOC(FunctionProtoType, {
    TRY_TO(TraverseTypeLoc(TL.getReturnLoc()));
  
    const FunctionProtoType *T = TL.getTypePtr();
  
    for (unsigned I = 0, E = TL.getNumParams(); I != E; ++I) {
      if (TL.getParam(I)) {
        TRY_TO(TraverseDecl(TL.getParam(I)));
      } else if (I < T->getNumParams()) {
        TRY_TO(TraverseType(T->getParamType(I)));
      }
    }
  
    for (const auto &E : T->exceptions()) {
      TRY_TO(TraverseType(E));
    }
  
    if (Expr *NE = T->getNoexceptExpr())
      TRY_TO(TraverseStmt(NE));
  })
  
  DEF_TRAVERSE_TYPELOC(UnresolvedUsingType, {})
  DEF_TRAVERSE_TYPELOC(TypedefType, {})
  
  DEF_TRAVERSE_TYPELOC(TypeOfExprType,
                       { TRY_TO(TraverseStmt(TL.getUnderlyingExpr())); })
  
  DEF_TRAVERSE_TYPELOC(TypeOfType, {
    TRY_TO(TraverseTypeLoc(TL.getUnderlyingTInfo()->getTypeLoc()));
  })
  
  // FIXME: location of underlying expr
  DEF_TRAVERSE_TYPELOC(DecltypeType, {
    TRY_TO(TraverseStmt(TL.getTypePtr()->getUnderlyingExpr()));
  })
  
  DEF_TRAVERSE_TYPELOC(UnaryTransformType, {
    TRY_TO(TraverseTypeLoc(TL.getUnderlyingTInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_TYPELOC(AutoType, {
    TRY_TO(TraverseType(TL.getTypePtr()->getDeducedType()));
  })
  
  DEF_TRAVERSE_TYPELOC(DeducedTemplateSpecializationType, {
    TRY_TO(TraverseTemplateName(TL.getTypePtr()->getTemplateName()));
    TRY_TO(TraverseType(TL.getTypePtr()->getDeducedType()));
  })
  
  DEF_TRAVERSE_TYPELOC(RecordType, {})
  DEF_TRAVERSE_TYPELOC(EnumType, {})
  DEF_TRAVERSE_TYPELOC(TemplateTypeParmType, {})
  DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmType, {
    TRY_TO(TraverseType(TL.getTypePtr()->getReplacementType()));
  })
  DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmPackType, {
    TRY_TO(TraverseTemplateArgument(TL.getTypePtr()->getArgumentPack()));
  })
  
  // FIXME: use the loc for the template name?
  DEF_TRAVERSE_TYPELOC(TemplateSpecializationType, {
    TRY_TO(TraverseTemplateName(TL.getTypePtr()->getTemplateName()));
    for (unsigned I = 0, E = TL.getNumArgs(); I != E; ++I) {
      TRY_TO(TraverseTemplateArgumentLoc(TL.getArgLoc(I)));
    }
  })
  
  DEF_TRAVERSE_TYPELOC(InjectedClassNameType, {})
  
  DEF_TRAVERSE_TYPELOC(ParenType, { TRY_TO(TraverseTypeLoc(TL.getInnerLoc())); })
  
  DEF_TRAVERSE_TYPELOC(AttributedType,
                       { TRY_TO(TraverseTypeLoc(TL.getModifiedLoc())); })
  
  DEF_TRAVERSE_TYPELOC(ElaboratedType, {
    if (TL.getQualifierLoc()) {
      TRY_TO(TraverseNestedNameSpecifierLoc(TL.getQualifierLoc()));
    }
    TRY_TO(TraverseTypeLoc(TL.getNamedTypeLoc()));
  })
  
  DEF_TRAVERSE_TYPELOC(DependentNameType, {
    TRY_TO(TraverseNestedNameSpecifierLoc(TL.getQualifierLoc()));
  })
  
  DEF_TRAVERSE_TYPELOC(DependentTemplateSpecializationType, {
    if (TL.getQualifierLoc()) {
      TRY_TO(TraverseNestedNameSpecifierLoc(TL.getQualifierLoc()));
    }
  
    for (unsigned I = 0, E = TL.getNumArgs(); I != E; ++I) {
      TRY_TO(TraverseTemplateArgumentLoc(TL.getArgLoc(I)));
    }
  })
  
  DEF_TRAVERSE_TYPELOC(PackExpansionType,
                       { TRY_TO(TraverseTypeLoc(TL.getPatternLoc())); })
  
  DEF_TRAVERSE_TYPELOC(ObjCTypeParamType, {})
  
  DEF_TRAVERSE_TYPELOC(ObjCInterfaceType, {})
  
  DEF_TRAVERSE_TYPELOC(ObjCObjectType, {
    // We have to watch out here because an ObjCInterfaceType's base
    // type is itself.
    if (TL.getTypePtr()->getBaseType().getTypePtr() != TL.getTypePtr())
      TRY_TO(TraverseTypeLoc(TL.getBaseLoc()));
    for (unsigned i = 0, n = TL.getNumTypeArgs(); i != n; ++i)
      TRY_TO(TraverseTypeLoc(TL.getTypeArgTInfo(i)->getTypeLoc()));
  })
  
  DEF_TRAVERSE_TYPELOC(ObjCObjectPointerType,
                       { TRY_TO(TraverseTypeLoc(TL.getPointeeLoc())); })
  
  DEF_TRAVERSE_TYPELOC(AtomicType, { TRY_TO(TraverseTypeLoc(TL.getValueLoc())); })
  
  DEF_TRAVERSE_TYPELOC(PipeType, { TRY_TO(TraverseTypeLoc(TL.getValueLoc())); })
  
  #undef DEF_TRAVERSE_TYPELOC
  
  // ----------------- Decl traversal -----------------
  //
  // For a Decl, we automate (in the DEF_TRAVERSE_DECL macro) traversing
  // the children that come from the DeclContext associated with it.
  // Therefore each Traverse* only needs to worry about children other
  // than those.
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::canIgnoreChildDeclWhileTraversingDeclContext(
      const Decl *Child) {
    // BlockDecls are traversed through BlockExprs,
    // CapturedDecls are traversed through CapturedStmts.
    if (isa<BlockDecl>(Child) || isa<CapturedDecl>(Child))
      return true;
    // Lambda classes are traversed through LambdaExprs.
    if (const CXXRecordDecl* Cls = dyn_cast<CXXRecordDecl>(Child))
      return Cls->isLambda();
    return false;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseDeclContextHelper(DeclContext *DC) {
    if (!DC)
      return true;
  
    for (auto *Child : DC->decls()) {
      if (!canIgnoreChildDeclWhileTraversingDeclContext(Child))
        TRY_TO(TraverseDecl(Child));
    }
  
    return true;
  }
  
  // This macro makes available a variable D, the passed-in decl.
  #define DEF_TRAVERSE_DECL(DECL, CODE)                                          \
    template <typename Derived>                                                  \
    bool RecursiveASTVisitor<Derived>::Traverse##DECL(DECL *D) {                 \
      bool ShouldVisitChildren = true;                                           \
      bool ReturnValue = true;                                                   \
      if (!getDerived().shouldTraversePostOrder())                               \
        TRY_TO(WalkUpFrom##DECL(D));                                             \
      { CODE; }                                                                  \
      if (ReturnValue && ShouldVisitChildren)                                    \
        TRY_TO(TraverseDeclContextHelper(dyn_cast<DeclContext>(D)));             \
      if (ReturnValue && getDerived().shouldTraversePostOrder())                 \
        TRY_TO(WalkUpFrom##DECL(D));                                             \
      return ReturnValue;                                                        \
    }
  
  DEF_TRAVERSE_DECL(AccessSpecDecl, {})
  
  DEF_TRAVERSE_DECL(BlockDecl, {
    if (TypeSourceInfo *TInfo = D->getSignatureAsWritten())
      TRY_TO(TraverseTypeLoc(TInfo->getTypeLoc()));
    TRY_TO(TraverseStmt(D->getBody()));
    for (const auto &I : D->captures()) {
      if (I.hasCopyExpr()) {
        TRY_TO(TraverseStmt(I.getCopyExpr()));
      }
    }
    ShouldVisitChildren = false;
  })
  
  DEF_TRAVERSE_DECL(CapturedDecl, {
    TRY_TO(TraverseStmt(D->getBody()));
    ShouldVisitChildren = false;
  })
  
  DEF_TRAVERSE_DECL(EmptyDecl, {})
  
  DEF_TRAVERSE_DECL(FileScopeAsmDecl,
                    { TRY_TO(TraverseStmt(D->getAsmString())); })
  
  DEF_TRAVERSE_DECL(ImportDecl, {})
  
  DEF_TRAVERSE_DECL(FriendDecl, {
    // Friend is either decl or a type.
    if (D->getFriendType())
      TRY_TO(TraverseTypeLoc(D->getFriendType()->getTypeLoc()));
    else
      TRY_TO(TraverseDecl(D->getFriendDecl()));
  })
  
  DEF_TRAVERSE_DECL(FriendTemplateDecl, {
    if (D->getFriendType())
      TRY_TO(TraverseTypeLoc(D->getFriendType()->getTypeLoc()));
    else
      TRY_TO(TraverseDecl(D->getFriendDecl()));
    for (unsigned I = 0, E = D->getNumTemplateParameters(); I < E; ++I) {
      TemplateParameterList *TPL = D->getTemplateParameterList(I);
      for (TemplateParameterList::iterator ITPL = TPL->begin(), ETPL = TPL->end();
           ITPL != ETPL; ++ITPL) {
        TRY_TO(TraverseDecl(*ITPL));
      }
    }
  })
  
  DEF_TRAVERSE_DECL(ClassScopeFunctionSpecializationDecl, {
    TRY_TO(TraverseDecl(D->getSpecialization()));
  
    if (D->hasExplicitTemplateArgs()) {
      const TemplateArgumentListInfo &args = D->templateArgs();
      TRY_TO(TraverseTemplateArgumentLocsHelper(args.getArgumentArray(),
                                                args.size()));
    }
  })
  
  DEF_TRAVERSE_DECL(LinkageSpecDecl, {})
  
  DEF_TRAVERSE_DECL(ExportDecl, {})
  
  DEF_TRAVERSE_DECL(ObjCPropertyImplDecl, {// FIXME: implement this
                                          })
  
  DEF_TRAVERSE_DECL(StaticAssertDecl, {
    TRY_TO(TraverseStmt(D->getAssertExpr()));
    TRY_TO(TraverseStmt(D->getMessage()));
  })
  
  DEF_TRAVERSE_DECL(
      TranslationUnitDecl,
      {// Code in an unnamed namespace shows up automatically in
       // decls_begin()/decls_end().  Thus we don't need to recurse on
       // D->getAnonymousNamespace().
      })
  
  DEF_TRAVERSE_DECL(PragmaCommentDecl, {})
  
  DEF_TRAVERSE_DECL(PragmaDetectMismatchDecl, {})
  
  DEF_TRAVERSE_DECL(ExternCContextDecl, {})
  
  DEF_TRAVERSE_DECL(NamespaceAliasDecl, {
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
  
    // We shouldn't traverse an aliased namespace, since it will be
    // defined (and, therefore, traversed) somewhere else.
    ShouldVisitChildren = false;
  })
  
  DEF_TRAVERSE_DECL(LabelDecl, {// There is no code in a LabelDecl.
                               })
  
  DEF_TRAVERSE_DECL(
      NamespaceDecl,
      {// Code in an unnamed namespace shows up automatically in
       // decls_begin()/decls_end().  Thus we don't need to recurse on
       // D->getAnonymousNamespace().
      })
  
  DEF_TRAVERSE_DECL(ObjCCompatibleAliasDecl, {// FIXME: implement
                                             })
  
  DEF_TRAVERSE_DECL(ObjCCategoryDecl, {// FIXME: implement
    if (ObjCTypeParamList *typeParamList = D->getTypeParamList()) {
      for (auto typeParam : *typeParamList) {
        TRY_TO(TraverseObjCTypeParamDecl(typeParam));
      }
    }
  })
  
  DEF_TRAVERSE_DECL(ObjCCategoryImplDecl, {// FIXME: implement
                                          })
  
  DEF_TRAVERSE_DECL(ObjCImplementationDecl, {// FIXME: implement
                                            })
  
  DEF_TRAVERSE_DECL(ObjCInterfaceDecl, {// FIXME: implement
    if (ObjCTypeParamList *typeParamList = D->getTypeParamListAsWritten()) {
      for (auto typeParam : *typeParamList) {
        TRY_TO(TraverseObjCTypeParamDecl(typeParam));
      }
    }
  
    if (TypeSourceInfo *superTInfo = D->getSuperClassTInfo()) {
      TRY_TO(TraverseTypeLoc(superTInfo->getTypeLoc()));
    }
  })
  
  DEF_TRAVERSE_DECL(ObjCProtocolDecl, {// FIXME: implement
                                      })
  
  DEF_TRAVERSE_DECL(ObjCMethodDecl, {
    if (D->getReturnTypeSourceInfo()) {
      TRY_TO(TraverseTypeLoc(D->getReturnTypeSourceInfo()->getTypeLoc()));
    }
    for (ParmVarDecl *Parameter : D->parameters()) {
      TRY_TO(TraverseDecl(Parameter));
    }
    if (D->isThisDeclarationADefinition()) {
      TRY_TO(TraverseStmt(D->getBody()));
    }
    ShouldVisitChildren = false;
  })
  
  DEF_TRAVERSE_DECL(ObjCTypeParamDecl, {
    if (D->hasExplicitBound()) {
      TRY_TO(TraverseTypeLoc(D->getTypeSourceInfo()->getTypeLoc()));
      // We shouldn't traverse D->getTypeForDecl(); it's a result of
      // declaring the type alias, not something that was written in the
      // source.
    }
  })
  
  DEF_TRAVERSE_DECL(ObjCPropertyDecl, {
    if (D->getTypeSourceInfo())
      TRY_TO(TraverseTypeLoc(D->getTypeSourceInfo()->getTypeLoc()));
    else
      TRY_TO(TraverseType(D->getType()));
    ShouldVisitChildren = false;
  })
  
  DEF_TRAVERSE_DECL(UsingDecl, {
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(D->getNameInfo()));
  })
  
  DEF_TRAVERSE_DECL(UsingPackDecl, {})
  
  DEF_TRAVERSE_DECL(UsingDirectiveDecl, {
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
  })
  
  DEF_TRAVERSE_DECL(UsingShadowDecl, {})
  
  DEF_TRAVERSE_DECL(ConstructorUsingShadowDecl, {})
  
  DEF_TRAVERSE_DECL(OMPThreadPrivateDecl, {
    for (auto *I : D->varlists()) {
      TRY_TO(TraverseStmt(I));
    }
   })
   
  DEF_TRAVERSE_DECL(OMPRequiresDecl, {
    for (auto *C : D->clauselists()) {
      TRY_TO(TraverseOMPClause(C));
    }
  })
  
  DEF_TRAVERSE_DECL(OMPDeclareReductionDecl, {
    TRY_TO(TraverseStmt(D->getCombiner()));
    if (auto *Initializer = D->getInitializer())
      TRY_TO(TraverseStmt(Initializer));
    TRY_TO(TraverseType(D->getType()));
    return true;
  })
  
  DEF_TRAVERSE_DECL(OMPCapturedExprDecl, { TRY_TO(TraverseVarHelper(D)); })
  
  // A helper method for TemplateDecl's children.
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateParameterListHelper(
      TemplateParameterList *TPL) {
    if (TPL) {
      for (TemplateParameterList::iterator I = TPL->begin(), E = TPL->end();
           I != E; ++I) {
        TRY_TO(TraverseDecl(*I));
      }
    }
    return true;
  }
  
  template <typename Derived>
  template <typename T>
  bool RecursiveASTVisitor<Derived>::TraverseDeclTemplateParameterLists(T *D) {
    for (unsigned i = 0; i < D->getNumTemplateParameterLists(); i++) {
      TemplateParameterList *TPL = D->getTemplateParameterList(i);
      TraverseTemplateParameterListHelper(TPL);
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateInstantiations(
      ClassTemplateDecl *D) {
    for (auto *SD : D->specializations()) {
      for (auto *RD : SD->redecls()) {
        // We don't want to visit injected-class-names in this traversal.
        if (cast<CXXRecordDecl>(RD)->isInjectedClassName())
          continue;
  
        switch (
            cast<ClassTemplateSpecializationDecl>(RD)->getSpecializationKind()) {
        // Visit the implicit instantiations with the requested pattern.
        case TSK_Undeclared:
        case TSK_ImplicitInstantiation:
          TRY_TO(TraverseDecl(RD));
          break;
  
        // We don't need to do anything on an explicit instantiation
        // or explicit specialization because there will be an explicit
        // node for it elsewhere.
        case TSK_ExplicitInstantiationDeclaration:
        case TSK_ExplicitInstantiationDefinition:
        case TSK_ExplicitSpecialization:
          break;
        }
      }
    }
  
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateInstantiations(
      VarTemplateDecl *D) {
    for (auto *SD : D->specializations()) {
      for (auto *RD : SD->redecls()) {
        switch (
            cast<VarTemplateSpecializationDecl>(RD)->getSpecializationKind()) {
        case TSK_Undeclared:
        case TSK_ImplicitInstantiation:
          TRY_TO(TraverseDecl(RD));
          break;
  
        case TSK_ExplicitInstantiationDeclaration:
        case TSK_ExplicitInstantiationDefinition:
        case TSK_ExplicitSpecialization:
          break;
        }
      }
    }
  
    return true;
  }
  
  // A helper method for traversing the instantiations of a
  // function while skipping its specializations.
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateInstantiations(
      FunctionTemplateDecl *D) {
    for (auto *FD : D->specializations()) {
      for (auto *RD : FD->redecls()) {
        switch (RD->getTemplateSpecializationKind()) {
        case TSK_Undeclared:
        case TSK_ImplicitInstantiation:
          // We don't know what kind of FunctionDecl this is.
          TRY_TO(TraverseDecl(RD));
          break;
  
        // FIXME: For now traverse explicit instantiations here. Change that
        // once they are represented as dedicated nodes in the AST.
        case TSK_ExplicitInstantiationDeclaration:
        case TSK_ExplicitInstantiationDefinition:
          TRY_TO(TraverseDecl(RD));
          break;
  
        case TSK_ExplicitSpecialization:
          break;
        }
      }
    }
  
    return true;
  }
  
  // This macro unifies the traversal of class, variable and function
  // template declarations.
  #define DEF_TRAVERSE_TMPL_DECL(TMPLDECLKIND)                                   \
    DEF_TRAVERSE_DECL(TMPLDECLKIND##TemplateDecl, {                              \
      TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));   \
      TRY_TO(TraverseDecl(D->getTemplatedDecl()));                               \
                                                                                 \
      /* By default, we do not traverse the instantiations of                    \
         class templates since they do not appear in the user code. The          \
         following code optionally traverses them.                               \
                                                                                 \
         We only traverse the class instantiations when we see the canonical     \
         declaration of the template, to ensure we only visit them once. */      \
      if (getDerived().shouldVisitTemplateInstantiations() &&                    \
          D == D->getCanonicalDecl())                                            \
        TRY_TO(TraverseTemplateInstantiations(D));                               \
                                                                                 \
      /* Note that getInstantiatedFromMemberTemplate() is just a link            \
         from a template instantiation back to the template from which           \
         it was instantiated, and thus should not be traversed. */               \
    })
  
  DEF_TRAVERSE_TMPL_DECL(Class)
  DEF_TRAVERSE_TMPL_DECL(Var)
  DEF_TRAVERSE_TMPL_DECL(Function)
  
  DEF_TRAVERSE_DECL(TemplateTemplateParmDecl, {
    // D is the "T" in something like
    //   template <template <typename> class T> class container { };
    TRY_TO(TraverseDecl(D->getTemplatedDecl()));
    if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {
      TRY_TO(TraverseTemplateArgumentLoc(D->getDefaultArgument()));
    }
    TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));
  })
  
  DEF_TRAVERSE_DECL(BuiltinTemplateDecl, {
    TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));
  })
  
  DEF_TRAVERSE_DECL(TemplateTypeParmDecl, {
    // D is the "T" in something like "template<typename T> class vector;"
    if (D->getTypeForDecl())
      TRY_TO(TraverseType(QualType(D->getTypeForDecl(), 0)));
    if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited())
      TRY_TO(TraverseTypeLoc(D->getDefaultArgumentInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_DECL(TypedefDecl, {
    TRY_TO(TraverseTypeLoc(D->getTypeSourceInfo()->getTypeLoc()));
    // We shouldn't traverse D->getTypeForDecl(); it's a result of
    // declaring the typedef, not something that was written in the
    // source.
  })
  
  DEF_TRAVERSE_DECL(TypeAliasDecl, {
    TRY_TO(TraverseTypeLoc(D->getTypeSourceInfo()->getTypeLoc()));
    // We shouldn't traverse D->getTypeForDecl(); it's a result of
    // declaring the type alias, not something that was written in the
    // source.
  })
  
  DEF_TRAVERSE_DECL(TypeAliasTemplateDecl, {
    TRY_TO(TraverseDecl(D->getTemplatedDecl()));
    TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));
  })
  
  DEF_TRAVERSE_DECL(UnresolvedUsingTypenameDecl, {
    // A dependent using declaration which was marked with 'typename'.
    //   template<class T> class A : public B<T> { using typename B<T>::foo; };
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
    // We shouldn't traverse D->getTypeForDecl(); it's a result of
    // declaring the type, not something that was written in the
    // source.
  })
  
  DEF_TRAVERSE_DECL(EnumDecl, {
    TRY_TO(TraverseDeclTemplateParameterLists(D));
  
    if (D->getTypeForDecl())
      TRY_TO(TraverseType(QualType(D->getTypeForDecl(), 0)));
  
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
    // The enumerators are already traversed by
    // decls_begin()/decls_end().
  })
  
  // Helper methods for RecordDecl and its children.
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseRecordHelper(RecordDecl *D) {
    // We shouldn't traverse D->getTypeForDecl(); it's a result of
    // declaring the type, not something that was written in the source.
  
    TRY_TO(TraverseDeclTemplateParameterLists(D));
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseCXXBaseSpecifier(
      const CXXBaseSpecifier &Base) {
    TRY_TO(TraverseTypeLoc(Base.getTypeSourceInfo()->getTypeLoc()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseCXXRecordHelper(CXXRecordDecl *D) {
    if (!TraverseRecordHelper(D))
      return false;
    if (D->isCompleteDefinition()) {
      for (const auto &I : D->bases()) {
        TRY_TO(TraverseCXXBaseSpecifier(I));
      }
      // We don't traverse the friends or the conversions, as they are
      // already in decls_begin()/decls_end().
    }
    return true;
  }
  
  DEF_TRAVERSE_DECL(RecordDecl, { TRY_TO(TraverseRecordHelper(D)); })
  
  DEF_TRAVERSE_DECL(CXXRecordDecl, { TRY_TO(TraverseCXXRecordHelper(D)); })
  
  #define DEF_TRAVERSE_TMPL_SPEC_DECL(TMPLDECLKIND)                              \
    DEF_TRAVERSE_DECL(TMPLDECLKIND##TemplateSpecializationDecl, {                \
      /* For implicit instantiations ("set<int> x;"), we don't want to           \
         recurse at all, since the instatiated template isn't written in         \
         the source code anywhere.  (Note the instatiated *type* --              \
         set<int> -- is written, and will still get a callback of                \
         TemplateSpecializationType).  For explicit instantiations               \
         ("template set<int>;"), we do need a callback, since this               \
         is the only callback that's made for this instantiation.                \
         We use getTypeAsWritten() to distinguish. */                            \
      if (TypeSourceInfo *TSI = D->getTypeAsWritten())                           \
        TRY_TO(TraverseTypeLoc(TSI->getTypeLoc()));                              \
                                                                                 \
      TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));              \
      if (!getDerived().shouldVisitTemplateInstantiations() &&                   \
          D->getTemplateSpecializationKind() != TSK_ExplicitSpecialization)      \
        /* Returning from here skips traversing the                              \
           declaration context of the *TemplateSpecializationDecl                \
           (embedded in the DEF_TRAVERSE_DECL() macro)                           \
           which contains the instantiated members of the template. */           \
        return true;                                                             \
    })
  
  DEF_TRAVERSE_TMPL_SPEC_DECL(Class)
  DEF_TRAVERSE_TMPL_SPEC_DECL(Var)
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseTemplateArgumentLocsHelper(
      const TemplateArgumentLoc *TAL, unsigned Count) {
    for (unsigned I = 0; I < Count; ++I) {
      TRY_TO(TraverseTemplateArgumentLoc(TAL[I]));
    }
    return true;
  }
  
  #define DEF_TRAVERSE_TMPL_PART_SPEC_DECL(TMPLDECLKIND, DECLKIND)               \
    DEF_TRAVERSE_DECL(TMPLDECLKIND##TemplatePartialSpecializationDecl, {         \
      /* The partial specialization. */                                          \
      if (TemplateParameterList *TPL = D->getTemplateParameters()) {             \
        for (TemplateParameterList::iterator I = TPL->begin(), E = TPL->end();   \
             I != E; ++I) {                                                      \
          TRY_TO(TraverseDecl(*I));                                              \
        }                                                                        \
      }                                                                          \
      /* The args that remains unspecialized. */                                 \
      TRY_TO(TraverseTemplateArgumentLocsHelper(                                 \
          D->getTemplateArgsAsWritten()->getTemplateArgs(),                      \
          D->getTemplateArgsAsWritten()->NumTemplateArgs));                      \
                                                                                 \
      /* Don't need the *TemplatePartialSpecializationHelper, even               \
         though that's our parent class -- we already visit all the              \
         template args here. */                                                  \
      TRY_TO(Traverse##DECLKIND##Helper(D));                                     \
                                                                                 \
      /* Instantiations will have been visited with the primary template. */     \
    })
  
  DEF_TRAVERSE_TMPL_PART_SPEC_DECL(Class, CXXRecord)
  DEF_TRAVERSE_TMPL_PART_SPEC_DECL(Var, Var)
  
  DEF_TRAVERSE_DECL(EnumConstantDecl, { TRY_TO(TraverseStmt(D->getInitExpr())); })
  
  DEF_TRAVERSE_DECL(UnresolvedUsingValueDecl, {
    // Like UnresolvedUsingTypenameDecl, but without the 'typename':
    //    template <class T> Class A : public Base<T> { using Base<T>::foo; };
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(D->getNameInfo()));
  })
  
  DEF_TRAVERSE_DECL(IndirectFieldDecl, {})
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseDeclaratorHelper(DeclaratorDecl *D) {
    TRY_TO(TraverseDeclTemplateParameterLists(D));
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
    if (D->getTypeSourceInfo())
      TRY_TO(TraverseTypeLoc(D->getTypeSourceInfo()->getTypeLoc()));
    else
      TRY_TO(TraverseType(D->getType()));
    return true;
  }
  
  DEF_TRAVERSE_DECL(DecompositionDecl, {
    TRY_TO(TraverseVarHelper(D));
    for (auto *Binding : D->bindings()) {
      TRY_TO(TraverseDecl(Binding));
    }
  })
  
  DEF_TRAVERSE_DECL(BindingDecl, {
    if (getDerived().shouldVisitImplicitCode())
      TRY_TO(TraverseStmt(D->getBinding()));
  })
  
  DEF_TRAVERSE_DECL(MSPropertyDecl, { TRY_TO(TraverseDeclaratorHelper(D)); })
  
  DEF_TRAVERSE_DECL(FieldDecl, {
    TRY_TO(TraverseDeclaratorHelper(D));
    if (D->isBitField())
      TRY_TO(TraverseStmt(D->getBitWidth()));
    else if (D->hasInClassInitializer())
      TRY_TO(TraverseStmt(D->getInClassInitializer()));
  })
  
  DEF_TRAVERSE_DECL(ObjCAtDefsFieldDecl, {
    TRY_TO(TraverseDeclaratorHelper(D));
    if (D->isBitField())
      TRY_TO(TraverseStmt(D->getBitWidth()));
    // FIXME: implement the rest.
  })
  
  DEF_TRAVERSE_DECL(ObjCIvarDecl, {
    TRY_TO(TraverseDeclaratorHelper(D));
    if (D->isBitField())
      TRY_TO(TraverseStmt(D->getBitWidth()));
    // FIXME: implement the rest.
  })
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseFunctionHelper(FunctionDecl *D) {
    TRY_TO(TraverseDeclTemplateParameterLists(D));
    TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(D->getNameInfo()));
  
    // If we're an explicit template specialization, iterate over the
    // template args that were explicitly specified.  If we were doing
    // this in typing order, we'd do it between the return type and
    // the function args, but both are handled by the FunctionTypeLoc
    // above, so we have to choose one side.  I've decided to do before.
    if (const FunctionTemplateSpecializationInfo *FTSI =
            D->getTemplateSpecializationInfo()) {
      if (FTSI->getTemplateSpecializationKind() != TSK_Undeclared &&
          FTSI->getTemplateSpecializationKind() != TSK_ImplicitInstantiation) {
        // A specialization might not have explicit template arguments if it has
        // a templated return type and concrete arguments.
        if (const ASTTemplateArgumentListInfo *TALI =
                FTSI->TemplateArgumentsAsWritten) {
          TRY_TO(TraverseTemplateArgumentLocsHelper(TALI->getTemplateArgs(),
                                                    TALI->NumTemplateArgs));
        }
      }
    }
  
    // Visit the function type itself, which can be either
    // FunctionNoProtoType or FunctionProtoType, or a typedef.  This
    // also covers the return type and the function parameters,
    // including exception specifications.
    if (TypeSourceInfo *TSI = D->getTypeSourceInfo()) {
      TRY_TO(TraverseTypeLoc(TSI->getTypeLoc()));
    } else if (getDerived().shouldVisitImplicitCode()) {
      // Visit parameter variable declarations of the implicit function
      // if the traverser is visiting implicit code. Parameter variable
      // declarations do not have valid TypeSourceInfo, so to visit them
      // we need to traverse the declarations explicitly.
      for (ParmVarDecl *Parameter : D->parameters()) {
        TRY_TO(TraverseDecl(Parameter));
      }
    }
  
    if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(D)) {
      // Constructor initializers.
      for (auto *I : Ctor->inits()) {
        TRY_TO(TraverseConstructorInitializer(I));
      }
    }
  
    if (D->isThisDeclarationADefinition()) {
      TRY_TO(TraverseStmt(D->getBody())); // Function body.
    }
    return true;
  }
  
  DEF_TRAVERSE_DECL(FunctionDecl, {
    // We skip decls_begin/decls_end, which are already covered by
    // TraverseFunctionHelper().
    ShouldVisitChildren = false;
    ReturnValue = TraverseFunctionHelper(D);
  })
  
  DEF_TRAVERSE_DECL(CXXDeductionGuideDecl, {
    // We skip decls_begin/decls_end, which are already covered by
    // TraverseFunctionHelper().
    ShouldVisitChildren = false;
    ReturnValue = TraverseFunctionHelper(D);
  })
  
  DEF_TRAVERSE_DECL(CXXMethodDecl, {
    // We skip decls_begin/decls_end, which are already covered by
    // TraverseFunctionHelper().
    ShouldVisitChildren = false;
    ReturnValue = TraverseFunctionHelper(D);
  })
  
  DEF_TRAVERSE_DECL(CXXConstructorDecl, {
    // We skip decls_begin/decls_end, which are already covered by
    // TraverseFunctionHelper().
    ShouldVisitChildren = false;
    ReturnValue = TraverseFunctionHelper(D);
  })
  
  // CXXConversionDecl is the declaration of a type conversion operator.
  // It's not a cast expression.
  DEF_TRAVERSE_DECL(CXXConversionDecl, {
    // We skip decls_begin/decls_end, which are already covered by
    // TraverseFunctionHelper().
    ShouldVisitChildren = false;
    ReturnValue = TraverseFunctionHelper(D);
  })
  
  DEF_TRAVERSE_DECL(CXXDestructorDecl, {
    // We skip decls_begin/decls_end, which are already covered by
    // TraverseFunctionHelper().
    ShouldVisitChildren = false;
    ReturnValue = TraverseFunctionHelper(D);
  })
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseVarHelper(VarDecl *D) {
    TRY_TO(TraverseDeclaratorHelper(D));
    // Default params are taken care of when we traverse the ParmVarDecl.
    if (!isa<ParmVarDecl>(D) &&
        (!D->isCXXForRangeDecl() || getDerived().shouldVisitImplicitCode()))
      TRY_TO(TraverseStmt(D->getInit()));
    return true;
  }
  
  DEF_TRAVERSE_DECL(VarDecl, { TRY_TO(TraverseVarHelper(D)); })
  
  DEF_TRAVERSE_DECL(ImplicitParamDecl, { TRY_TO(TraverseVarHelper(D)); })
  
  DEF_TRAVERSE_DECL(NonTypeTemplateParmDecl, {
    // A non-type template parameter, e.g. "S" in template<int S> class Foo ...
    TRY_TO(TraverseDeclaratorHelper(D));
    if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited())
      TRY_TO(TraverseStmt(D->getDefaultArgument()));
  })
  
  DEF_TRAVERSE_DECL(ParmVarDecl, {
    TRY_TO(TraverseVarHelper(D));
  
    if (D->hasDefaultArg() && D->hasUninstantiatedDefaultArg() &&
        !D->hasUnparsedDefaultArg())
      TRY_TO(TraverseStmt(D->getUninstantiatedDefaultArg()));
  
    if (D->hasDefaultArg() && !D->hasUninstantiatedDefaultArg() &&
        !D->hasUnparsedDefaultArg())
      TRY_TO(TraverseStmt(D->getDefaultArg()));
  })
  
  #undef DEF_TRAVERSE_DECL
  
  // ----------------- Stmt traversal -----------------
  //
  // For stmts, we automate (in the DEF_TRAVERSE_STMT macro) iterating
  // over the children defined in children() (every stmt defines these,
  // though sometimes the range is empty).  Each individual Traverse*
  // method only needs to worry about children other than those.  To see
  // what children() does for a given class, see, e.g.,
  //   http://clang.llvm.org/doxygen/Stmt_8cpp_source.html
  
  // This macro makes available a variable S, the passed-in stmt.
  #define DEF_TRAVERSE_STMT(STMT, CODE)                                          \
    template <typename Derived>                                                  \
    bool RecursiveASTVisitor<Derived>::Traverse##STMT(                           \
        STMT *S, DataRecursionQueue *Queue) {                                    \
      bool ShouldVisitChildren = true;                                           \
      bool ReturnValue = true;                                                   \
      if (!getDerived().shouldTraversePostOrder())                               \
        TRY_TO(WalkUpFrom##STMT(S));                                             \
      { CODE; }                                                                  \
      if (ShouldVisitChildren) {                                                 \
        for (Stmt * SubStmt : getDerived().getStmtChildren(S)) {                 \
          TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(SubStmt);                              \
        }                                                                        \
      }                                                                          \
      if (!Queue && ReturnValue && getDerived().shouldTraversePostOrder())       \
        TRY_TO(WalkUpFrom##STMT(S));                                             \
      return ReturnValue;                                                        \
    }
  
  DEF_TRAVERSE_STMT(GCCAsmStmt, {
    TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getAsmString());
    for (unsigned I = 0, E = S->getNumInputs(); I < E; ++I) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getInputConstraintLiteral(I));
    }
    for (unsigned I = 0, E = S->getNumOutputs(); I < E; ++I) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOutputConstraintLiteral(I));
    }
    for (unsigned I = 0, E = S->getNumClobbers(); I < E; ++I) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getClobberStringLiteral(I));
    }
    // children() iterates over inputExpr and outputExpr.
  })
  
  DEF_TRAVERSE_STMT(
      MSAsmStmt,
      {// FIXME: MS Asm doesn't currently parse Constraints, Clobbers, etc.  Once
       // added this needs to be implemented.
      })
  
  DEF_TRAVERSE_STMT(CXXCatchStmt, {
    TRY_TO(TraverseDecl(S->getExceptionDecl()));
    // children() iterates over the handler block.
  })
  
  DEF_TRAVERSE_STMT(DeclStmt, {
    for (auto *I : S->decls()) {
      TRY_TO(TraverseDecl(I));
    }
    // Suppress the default iteration over children() by
    // returning.  Here's why: A DeclStmt looks like 'type var [=
    // initializer]'.  The decls above already traverse over the
    // initializers, so we don't have to do it again (which
    // children() would do).
    ShouldVisitChildren = false;
  })
  
  // These non-expr stmts (most of them), do not need any action except
  // iterating over the children.
  DEF_TRAVERSE_STMT(BreakStmt, {})
  DEF_TRAVERSE_STMT(CXXTryStmt, {})
  DEF_TRAVERSE_STMT(CaseStmt, {})
  DEF_TRAVERSE_STMT(CompoundStmt, {})
  DEF_TRAVERSE_STMT(ContinueStmt, {})
  DEF_TRAVERSE_STMT(DefaultStmt, {})
  DEF_TRAVERSE_STMT(DoStmt, {})
  DEF_TRAVERSE_STMT(ForStmt, {})
  DEF_TRAVERSE_STMT(GotoStmt, {})
  DEF_TRAVERSE_STMT(IfStmt, {})
  DEF_TRAVERSE_STMT(IndirectGotoStmt, {})
  DEF_TRAVERSE_STMT(LabelStmt, {})
  DEF_TRAVERSE_STMT(AttributedStmt, {})
  DEF_TRAVERSE_STMT(NullStmt, {})
  DEF_TRAVERSE_STMT(ObjCAtCatchStmt, {})
  DEF_TRAVERSE_STMT(ObjCAtFinallyStmt, {})
  DEF_TRAVERSE_STMT(ObjCAtSynchronizedStmt, {})
  DEF_TRAVERSE_STMT(ObjCAtThrowStmt, {})
  DEF_TRAVERSE_STMT(ObjCAtTryStmt, {})
  DEF_TRAVERSE_STMT(ObjCForCollectionStmt, {})
  DEF_TRAVERSE_STMT(ObjCAutoreleasePoolStmt, {})
  
  DEF_TRAVERSE_STMT(CXXForRangeStmt, {
    if (!getDerived().shouldVisitImplicitCode()) {
      if (S->getInit())
        TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getInit());
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getLoopVarStmt());
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getRangeInit());
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getBody());
      // Visit everything else only if shouldVisitImplicitCode().
      ShouldVisitChildren = false;
    }
  })
  
  DEF_TRAVERSE_STMT(MSDependentExistsStmt, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(S->getNameInfo()));
  })
  
  DEF_TRAVERSE_STMT(ReturnStmt, {})
  DEF_TRAVERSE_STMT(SwitchStmt, {})
  DEF_TRAVERSE_STMT(WhileStmt, {})
  
  DEF_TRAVERSE_STMT(ConstantExpr, {})
  
  DEF_TRAVERSE_STMT(CXXDependentScopeMemberExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(S->getMemberNameInfo()));
    if (S->hasExplicitTemplateArgs()) {
      TRY_TO(TraverseTemplateArgumentLocsHelper(S->getTemplateArgs(),
                                                S->getNumTemplateArgs()));
    }
  })
  
  DEF_TRAVERSE_STMT(DeclRefExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(S->getNameInfo()));
    TRY_TO(TraverseTemplateArgumentLocsHelper(S->getTemplateArgs(),
                                              S->getNumTemplateArgs()));
  })
  
  DEF_TRAVERSE_STMT(DependentScopeDeclRefExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(S->getNameInfo()));
    if (S->hasExplicitTemplateArgs()) {
      TRY_TO(TraverseTemplateArgumentLocsHelper(S->getTemplateArgs(),
                                                S->getNumTemplateArgs()));
    }
  })
  
  DEF_TRAVERSE_STMT(MemberExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(S->getMemberNameInfo()));
    TRY_TO(TraverseTemplateArgumentLocsHelper(S->getTemplateArgs(),
                                              S->getNumTemplateArgs()));
  })
  
  DEF_TRAVERSE_STMT(
      ImplicitCastExpr,
      {// We don't traverse the cast type, as it's not written in the
       // source code.
      })
  
  DEF_TRAVERSE_STMT(CStyleCastExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXFunctionalCastExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXConstCastExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXDynamicCastExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXReinterpretCastExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXStaticCastExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
  })
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseSynOrSemInitListExpr(
      InitListExpr *S, DataRecursionQueue *Queue) {
    if (S) {
      // Skip this if we traverse postorder. We will visit it later
      // in PostVisitStmt.
      if (!getDerived().shouldTraversePostOrder())
        TRY_TO(WalkUpFromInitListExpr(S));
  
      // All we need are the default actions.  FIXME: use a helper function.
      for (Stmt *SubStmt : S->children()) {
        TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(SubStmt);
      }
    }
    return true;
  }
  
  // This method is called once for each pair of syntactic and semantic
  // InitListExpr, and it traverses the subtrees defined by the two forms. This
  // may cause some of the children to be visited twice, if they appear both in
  // the syntactic and the semantic form.
  //
  // There is no guarantee about which form \p S takes when this method is called.
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseInitListExpr(
      InitListExpr *S, DataRecursionQueue *Queue) {
    TRY_TO(TraverseSynOrSemInitListExpr(
        S->isSemanticForm() ? S->getSyntacticForm() : S, Queue));
    TRY_TO(TraverseSynOrSemInitListExpr(
        S->isSemanticForm() ? S : S->getSemanticForm(), Queue));
    return true;
  }
  
  // GenericSelectionExpr is a special case because the types and expressions
  // are interleaved.  We also need to watch out for null types (default
  // generic associations).
  DEF_TRAVERSE_STMT(GenericSelectionExpr, {
    TRY_TO(TraverseStmt(S->getControllingExpr()));
    for (unsigned i = 0; i != S->getNumAssocs(); ++i) {
      if (TypeSourceInfo *TS = S->getAssocTypeSourceInfo(i))
        TRY_TO(TraverseTypeLoc(TS->getTypeLoc()));
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getAssocExpr(i));
    }
    ShouldVisitChildren = false;
  })
  
  // PseudoObjectExpr is a special case because of the weirdness with
  // syntactic expressions and opaque values.
  DEF_TRAVERSE_STMT(PseudoObjectExpr, {
    TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getSyntacticForm());
    for (PseudoObjectExpr::semantics_iterator i = S->semantics_begin(),
                                              e = S->semantics_end();
         i != e; ++i) {
      Expr *sub = *i;
      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(sub))
        sub = OVE->getSourceExpr();
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(sub);
    }
    ShouldVisitChildren = false;
  })
  
  DEF_TRAVERSE_STMT(CXXScalarValueInitExpr, {
    // This is called for code like 'return T()' where T is a built-in
    // (i.e. non-class) type.
    TRY_TO(TraverseTypeLoc(S->getTypeSourceInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXNewExpr, {
    // The child-iterator will pick up the other arguments.
    TRY_TO(TraverseTypeLoc(S->getAllocatedTypeSourceInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(OffsetOfExpr, {
    // The child-iterator will pick up the expression representing
    // the field.
    // FIMXE: for code like offsetof(Foo, a.b.c), should we get
    // making a MemberExpr callbacks for Foo.a, Foo.a.b, and Foo.a.b.c?
    TRY_TO(TraverseTypeLoc(S->getTypeSourceInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(UnaryExprOrTypeTraitExpr, {
    // The child-iterator will pick up the arg if it's an expression,
    // but not if it's a type.
    if (S->isArgumentType())
      TRY_TO(TraverseTypeLoc(S->getArgumentTypeInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXTypeidExpr, {
    // The child-iterator will pick up the arg if it's an expression,
    // but not if it's a type.
    if (S->isTypeOperand())
      TRY_TO(TraverseTypeLoc(S->getTypeOperandSourceInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(MSPropertyRefExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
  })
  
  DEF_TRAVERSE_STMT(MSPropertySubscriptExpr, {})
  
  DEF_TRAVERSE_STMT(CXXUuidofExpr, {
    // The child-iterator will pick up the arg if it's an expression,
    // but not if it's a type.
    if (S->isTypeOperand())
      TRY_TO(TraverseTypeLoc(S->getTypeOperandSourceInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(TypeTraitExpr, {
    for (unsigned I = 0, N = S->getNumArgs(); I != N; ++I)
      TRY_TO(TraverseTypeLoc(S->getArg(I)->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(ArrayTypeTraitExpr, {
    TRY_TO(TraverseTypeLoc(S->getQueriedTypeSourceInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(ExpressionTraitExpr,
                    { TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getQueriedExpression()); })
  
  DEF_TRAVERSE_STMT(VAArgExpr, {
    // The child-iterator will pick up the expression argument.
    TRY_TO(TraverseTypeLoc(S->getWrittenTypeInfo()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXTemporaryObjectExpr, {
    // This is called for code like 'return T()' where T is a class type.
    TRY_TO(TraverseTypeLoc(S->getTypeSourceInfo()->getTypeLoc()));
  })
  
  // Walk only the visible parts of lambda expressions.
  DEF_TRAVERSE_STMT(LambdaExpr, {
    // Visit the capture list.
    for (unsigned I = 0, N = S->capture_size(); I != N; ++I) {
      const LambdaCapture *C = S->capture_begin() + I;
      if (C->isExplicit() || getDerived().shouldVisitImplicitCode()) {
        TRY_TO(TraverseLambdaCapture(S, C, S->capture_init_begin()[I]));
      }
    }
  
    if (getDerived().shouldVisitImplicitCode()) {
      // The implicit model is simple: everything else is in the lambda class.
      TRY_TO(TraverseDecl(S->getLambdaClass()));
    } else {
      // We need to poke around to find the bits that might be explicitly written.
      TypeLoc TL = S->getCallOperator()->getTypeSourceInfo()->getTypeLoc();
      FunctionProtoTypeLoc Proto = TL.getAsAdjusted<FunctionProtoTypeLoc>();
  
      if (S->hasExplicitParameters()) {
        // Visit parameters.
        for (unsigned I = 0, N = Proto.getNumParams(); I != N; ++I)
          TRY_TO(TraverseDecl(Proto.getParam(I)));
      }
      if (S->hasExplicitResultType())
        TRY_TO(TraverseTypeLoc(Proto.getReturnLoc()));
  
      auto *T = Proto.getTypePtr();
      for (const auto &E : T->exceptions())
        TRY_TO(TraverseType(E));
  
      if (Expr *NE = T->getNoexceptExpr())
        TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(NE);
  
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getBody());
    }
    ShouldVisitChildren = false;
  })
  
  DEF_TRAVERSE_STMT(CXXUnresolvedConstructExpr, {
    // This is called for code like 'T()', where T is a template argument.
    TRY_TO(TraverseTypeLoc(S->getTypeSourceInfo()->getTypeLoc()));
  })
  
  // These expressions all might take explicit template arguments.
  // We traverse those if so.  FIXME: implement these.
  DEF_TRAVERSE_STMT(CXXConstructExpr, {})
  DEF_TRAVERSE_STMT(CallExpr, {})
  DEF_TRAVERSE_STMT(CXXMemberCallExpr, {})
  
  // These exprs (most of them), do not need any action except iterating
  // over the children.
  DEF_TRAVERSE_STMT(AddrLabelExpr, {})
  DEF_TRAVERSE_STMT(ArraySubscriptExpr, {})
  DEF_TRAVERSE_STMT(OMPArraySectionExpr, {})
  
  DEF_TRAVERSE_STMT(BlockExpr, {
    TRY_TO(TraverseDecl(S->getBlockDecl()));
    return true; // no child statements to loop through.
  })
  
  DEF_TRAVERSE_STMT(ChooseExpr, {})
  DEF_TRAVERSE_STMT(CompoundLiteralExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeSourceInfo()->getTypeLoc()));
  })
  DEF_TRAVERSE_STMT(CXXBindTemporaryExpr, {})
  DEF_TRAVERSE_STMT(CXXBoolLiteralExpr, {})
  
  DEF_TRAVERSE_STMT(CXXDefaultArgExpr, {
    if (getDerived().shouldVisitImplicitCode())
      TRY_TO(TraverseStmt(S->getExpr()));
  })
  
  DEF_TRAVERSE_STMT(CXXDefaultInitExpr, {})
  DEF_TRAVERSE_STMT(CXXDeleteExpr, {})
  DEF_TRAVERSE_STMT(ExprWithCleanups, {})
  DEF_TRAVERSE_STMT(CXXInheritedCtorInitExpr, {})
  DEF_TRAVERSE_STMT(CXXNullPtrLiteralExpr, {})
  DEF_TRAVERSE_STMT(CXXStdInitializerListExpr, {})
  
  DEF_TRAVERSE_STMT(CXXPseudoDestructorExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    if (TypeSourceInfo *ScopeInfo = S->getScopeTypeInfo())
      TRY_TO(TraverseTypeLoc(ScopeInfo->getTypeLoc()));
    if (TypeSourceInfo *DestroyedTypeInfo = S->getDestroyedTypeInfo())
      TRY_TO(TraverseTypeLoc(DestroyedTypeInfo->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(CXXThisExpr, {})
  DEF_TRAVERSE_STMT(CXXThrowExpr, {})
  DEF_TRAVERSE_STMT(UserDefinedLiteral, {})
  DEF_TRAVERSE_STMT(DesignatedInitExpr, {})
  DEF_TRAVERSE_STMT(DesignatedInitUpdateExpr, {})
  DEF_TRAVERSE_STMT(ExtVectorElementExpr, {})
  DEF_TRAVERSE_STMT(GNUNullExpr, {})
  DEF_TRAVERSE_STMT(ImplicitValueInitExpr, {})
  DEF_TRAVERSE_STMT(NoInitExpr, {})
  DEF_TRAVERSE_STMT(ArrayInitLoopExpr, {
    // FIXME: The source expression of the OVE should be listed as
    // a child of the ArrayInitLoopExpr.
    if (OpaqueValueExpr *OVE = S->getCommonExpr())
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(OVE->getSourceExpr());
  })
  DEF_TRAVERSE_STMT(ArrayInitIndexExpr, {})
  DEF_TRAVERSE_STMT(ObjCBoolLiteralExpr, {})
  
  DEF_TRAVERSE_STMT(ObjCEncodeExpr, {
    if (TypeSourceInfo *TInfo = S->getEncodedTypeSourceInfo())
      TRY_TO(TraverseTypeLoc(TInfo->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(ObjCIsaExpr, {})
  DEF_TRAVERSE_STMT(ObjCIvarRefExpr, {})
  
  DEF_TRAVERSE_STMT(ObjCMessageExpr, {
    if (TypeSourceInfo *TInfo = S->getClassReceiverTypeInfo())
      TRY_TO(TraverseTypeLoc(TInfo->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(ObjCPropertyRefExpr, {})
  DEF_TRAVERSE_STMT(ObjCSubscriptRefExpr, {})
  DEF_TRAVERSE_STMT(ObjCProtocolExpr, {})
  DEF_TRAVERSE_STMT(ObjCSelectorExpr, {})
  DEF_TRAVERSE_STMT(ObjCIndirectCopyRestoreExpr, {})
  
  DEF_TRAVERSE_STMT(ObjCBridgedCastExpr, {
    TRY_TO(TraverseTypeLoc(S->getTypeInfoAsWritten()->getTypeLoc()));
  })
  
  DEF_TRAVERSE_STMT(ObjCAvailabilityCheckExpr, {})
  DEF_TRAVERSE_STMT(ParenExpr, {})
  DEF_TRAVERSE_STMT(ParenListExpr, {})
  DEF_TRAVERSE_STMT(PredefinedExpr, {})
  DEF_TRAVERSE_STMT(ShuffleVectorExpr, {})
  DEF_TRAVERSE_STMT(ConvertVectorExpr, {})
  DEF_TRAVERSE_STMT(StmtExpr, {})
  DEF_TRAVERSE_STMT(UnresolvedLookupExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    if (S->hasExplicitTemplateArgs()) {
      TRY_TO(TraverseTemplateArgumentLocsHelper(S->getTemplateArgs(),
                                                S->getNumTemplateArgs()));
    }
  })
  
  DEF_TRAVERSE_STMT(UnresolvedMemberExpr, {
    TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
    if (S->hasExplicitTemplateArgs()) {
      TRY_TO(TraverseTemplateArgumentLocsHelper(S->getTemplateArgs(),
                                                S->getNumTemplateArgs()));
    }
  })
  
  DEF_TRAVERSE_STMT(SEHTryStmt, {})
  DEF_TRAVERSE_STMT(SEHExceptStmt, {})
  DEF_TRAVERSE_STMT(SEHFinallyStmt, {})
  DEF_TRAVERSE_STMT(SEHLeaveStmt, {})
  DEF_TRAVERSE_STMT(CapturedStmt, { TRY_TO(TraverseDecl(S->getCapturedDecl())); })
  
  DEF_TRAVERSE_STMT(CXXOperatorCallExpr, {})
  DEF_TRAVERSE_STMT(OpaqueValueExpr, {})
  DEF_TRAVERSE_STMT(TypoExpr, {})
  DEF_TRAVERSE_STMT(CUDAKernelCallExpr, {})
  
  // These operators (all of them) do not need any action except
  // iterating over the children.
  DEF_TRAVERSE_STMT(BinaryConditionalOperator, {})
  DEF_TRAVERSE_STMT(ConditionalOperator, {})
  DEF_TRAVERSE_STMT(UnaryOperator, {})
  DEF_TRAVERSE_STMT(BinaryOperator, {})
  DEF_TRAVERSE_STMT(CompoundAssignOperator, {})
  DEF_TRAVERSE_STMT(CXXNoexceptExpr, {})
  DEF_TRAVERSE_STMT(PackExpansionExpr, {})
  DEF_TRAVERSE_STMT(SizeOfPackExpr, {})
  DEF_TRAVERSE_STMT(SubstNonTypeTemplateParmPackExpr, {})
  DEF_TRAVERSE_STMT(SubstNonTypeTemplateParmExpr, {})
  DEF_TRAVERSE_STMT(FunctionParmPackExpr, {})
  DEF_TRAVERSE_STMT(MaterializeTemporaryExpr, {})
  DEF_TRAVERSE_STMT(CXXFoldExpr, {})
  DEF_TRAVERSE_STMT(AtomicExpr, {})
  
  // For coroutines expressions, traverse either the operand
  // as written or the implied calls, depending on what the
  // derived class requests.
  DEF_TRAVERSE_STMT(CoroutineBodyStmt, {
    if (!getDerived().shouldVisitImplicitCode()) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getBody());
      ShouldVisitChildren = false;
    }
  })
  DEF_TRAVERSE_STMT(CoreturnStmt, {
    if (!getDerived().shouldVisitImplicitCode()) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOperand());
      ShouldVisitChildren = false;
    }
  })
  DEF_TRAVERSE_STMT(CoawaitExpr, {
    if (!getDerived().shouldVisitImplicitCode()) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOperand());
      ShouldVisitChildren = false;
    }
  })
  DEF_TRAVERSE_STMT(DependentCoawaitExpr, {
    if (!getDerived().shouldVisitImplicitCode()) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOperand());
      ShouldVisitChildren = false;
    }
  })
  DEF_TRAVERSE_STMT(CoyieldExpr, {
    if (!getDerived().shouldVisitImplicitCode()) {
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOperand());
      ShouldVisitChildren = false;
    }
  })
  
  // These literals (all of them) do not need any action.
  DEF_TRAVERSE_STMT(IntegerLiteral, {})
  DEF_TRAVERSE_STMT(FixedPointLiteral, {})
  DEF_TRAVERSE_STMT(CharacterLiteral, {})
  DEF_TRAVERSE_STMT(FloatingLiteral, {})
  DEF_TRAVERSE_STMT(ImaginaryLiteral, {})
  DEF_TRAVERSE_STMT(StringLiteral, {})
  DEF_TRAVERSE_STMT(ObjCStringLiteral, {})
  DEF_TRAVERSE_STMT(ObjCBoxedExpr, {})
  DEF_TRAVERSE_STMT(ObjCArrayLiteral, {})
  DEF_TRAVERSE_STMT(ObjCDictionaryLiteral, {})
  
  // Traverse OpenCL: AsType, Convert.
  DEF_TRAVERSE_STMT(AsTypeExpr, {})
  
  // OpenMP directives.
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseOMPExecutableDirective(
      OMPExecutableDirective *S) {
    for (auto *C : S->clauses()) {
      TRY_TO(TraverseOMPClause(C));
    }
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::TraverseOMPLoopDirective(OMPLoopDirective *S) {
    return TraverseOMPExecutableDirective(S);
  }
  
  DEF_TRAVERSE_STMT(OMPParallelDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPForDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPForSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPSectionsDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPSectionDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPSingleDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPMasterDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPCriticalDirective, {
    TRY_TO(TraverseDeclarationNameInfo(S->getDirectiveName()));
    TRY_TO(TraverseOMPExecutableDirective(S));
  })
  
  DEF_TRAVERSE_STMT(OMPParallelForDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPParallelForSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPParallelSectionsDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTaskDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTaskyieldDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPBarrierDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTaskwaitDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTaskgroupDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPCancellationPointDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPCancelDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPFlushDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPOrderedDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPAtomicDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetDataDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetEnterDataDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetExitDataDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetParallelDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetParallelForDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTeamsDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetUpdateDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTaskLoopDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTaskLoopSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPDistributeDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPDistributeParallelForDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPDistributeParallelForSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPDistributeSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetParallelForSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTeamsDistributeDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTeamsDistributeSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTeamsDistributeParallelForSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTeamsDistributeParallelForDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetTeamsDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetTeamsDistributeDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetTeamsDistributeParallelForDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetTeamsDistributeParallelForSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  DEF_TRAVERSE_STMT(OMPTargetTeamsDistributeSimdDirective,
                    { TRY_TO(TraverseOMPExecutableDirective(S)); })
  
  // OpenMP clauses.
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::TraverseOMPClause(OMPClause *C) {
    if (!C)
      return true;
    switch (C->getClauseKind()) {
  #define OPENMP_CLAUSE(Name, Class)                                             \
    case OMPC_##Name:                                                            \
      TRY_TO(Visit##Class(static_cast<Class *>(C)));                             \
      break;
  #include "clang/Basic/OpenMPKinds.def"
    case OMPC_threadprivate:
    case OMPC_uniform:
    case OMPC_unknown:
      break;
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPClauseWithPreInit(
      OMPClauseWithPreInit *Node) {
    TRY_TO(TraverseStmt(Node->getPreInitStmt()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPClauseWithPostUpdate(
      OMPClauseWithPostUpdate *Node) {
    TRY_TO(VisitOMPClauseWithPreInit(Node));
    TRY_TO(TraverseStmt(Node->getPostUpdateExpr()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPIfClause(OMPIfClause *C) {
    TRY_TO(VisitOMPClauseWithPreInit(C));
    TRY_TO(TraverseStmt(C->getCondition()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPFinalClause(OMPFinalClause *C) {
    TRY_TO(TraverseStmt(C->getCondition()));
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::VisitOMPNumThreadsClause(OMPNumThreadsClause *C) {
    TRY_TO(VisitOMPClauseWithPreInit(C));
    TRY_TO(TraverseStmt(C->getNumThreads()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPSafelenClause(OMPSafelenClause *C) {
    TRY_TO(TraverseStmt(C->getSafelen()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPSimdlenClause(OMPSimdlenClause *C) {
    TRY_TO(TraverseStmt(C->getSimdlen()));
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::VisitOMPCollapseClause(OMPCollapseClause *C) {
    TRY_TO(TraverseStmt(C->getNumForLoops()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPDefaultClause(OMPDefaultClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPProcBindClause(OMPProcBindClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPUnifiedAddressClause(
      OMPUnifiedAddressClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPUnifiedSharedMemoryClause(
      OMPUnifiedSharedMemoryClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPReverseOffloadClause(
      OMPReverseOffloadClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPDynamicAllocatorsClause(
      OMPDynamicAllocatorsClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPAtomicDefaultMemOrderClause(
      OMPAtomicDefaultMemOrderClause *) {
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::VisitOMPScheduleClause(OMPScheduleClause *C) {
    TRY_TO(VisitOMPClauseWithPreInit(C));
    TRY_TO(TraverseStmt(C->getChunkSize()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPOrderedClause(OMPOrderedClause *C) {
    TRY_TO(TraverseStmt(C->getNumForLoops()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPNowaitClause(OMPNowaitClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPUntiedClause(OMPUntiedClause *) {
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::VisitOMPMergeableClause(OMPMergeableClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPReadClause(OMPReadClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPWriteClause(OMPWriteClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPUpdateClause(OMPUpdateClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPCaptureClause(OMPCaptureClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPSeqCstClause(OMPSeqCstClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPThreadsClause(OMPThreadsClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPSIMDClause(OMPSIMDClause *) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPNogroupClause(OMPNogroupClause *) {
    return true;
  }
  
  template <typename Derived>
  template <typename T>
  bool RecursiveASTVisitor<Derived>::VisitOMPClauseList(T *Node) {
    for (auto *E : Node->varlists()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPPrivateClause(OMPPrivateClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    for (auto *E : C->private_copies()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPFirstprivateClause(
      OMPFirstprivateClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    TRY_TO(VisitOMPClauseWithPreInit(C));
    for (auto *E : C->private_copies()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->inits()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPLastprivateClause(
      OMPLastprivateClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    TRY_TO(VisitOMPClauseWithPostUpdate(C));
    for (auto *E : C->private_copies()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->source_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->destination_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->assignment_ops()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPSharedClause(OMPSharedClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPLinearClause(OMPLinearClause *C) {
    TRY_TO(TraverseStmt(C->getStep()));
    TRY_TO(TraverseStmt(C->getCalcStep()));
    TRY_TO(VisitOMPClauseList(C));
    TRY_TO(VisitOMPClauseWithPostUpdate(C));
    for (auto *E : C->privates()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->inits()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->updates()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->finals()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPAlignedClause(OMPAlignedClause *C) {
    TRY_TO(TraverseStmt(C->getAlignment()));
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPCopyinClause(OMPCopyinClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    for (auto *E : C->source_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->destination_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->assignment_ops()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPCopyprivateClause(
      OMPCopyprivateClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    for (auto *E : C->source_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->destination_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->assignment_ops()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::VisitOMPReductionClause(OMPReductionClause *C) {
    TRY_TO(TraverseNestedNameSpecifierLoc(C->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(C->getNameInfo()));
    TRY_TO(VisitOMPClauseList(C));
    TRY_TO(VisitOMPClauseWithPostUpdate(C));
    for (auto *E : C->privates()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->lhs_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->rhs_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->reduction_ops()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPTaskReductionClause(
      OMPTaskReductionClause *C) {
    TRY_TO(TraverseNestedNameSpecifierLoc(C->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(C->getNameInfo()));
    TRY_TO(VisitOMPClauseList(C));
    TRY_TO(VisitOMPClauseWithPostUpdate(C));
    for (auto *E : C->privates()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->lhs_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->rhs_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->reduction_ops()) {
      TRY_TO(TraverseStmt(E));
    }
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPInReductionClause(
      OMPInReductionClause *C) {
    TRY_TO(TraverseNestedNameSpecifierLoc(C->getQualifierLoc()));
    TRY_TO(TraverseDeclarationNameInfo(C->getNameInfo()));
    TRY_TO(VisitOMPClauseList(C));
    TRY_TO(VisitOMPClauseWithPostUpdate(C));
    for (auto *E : C->privates()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->lhs_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->rhs_exprs()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->reduction_ops()) {
      TRY_TO(TraverseStmt(E));
    }
    for (auto *E : C->taskgroup_descriptors())
      TRY_TO(TraverseStmt(E));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPFlushClause(OMPFlushClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPDependClause(OMPDependClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPDeviceClause(OMPDeviceClause *C) {
    TRY_TO(VisitOMPClauseWithPreInit(C));
    TRY_TO(TraverseStmt(C->getDevice()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPMapClause(OMPMapClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPNumTeamsClause(
      OMPNumTeamsClause *C) {
    TRY_TO(VisitOMPClauseWithPreInit(C));
    TRY_TO(TraverseStmt(C->getNumTeams()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPThreadLimitClause(
      OMPThreadLimitClause *C) {
    TRY_TO(VisitOMPClauseWithPreInit(C));
    TRY_TO(TraverseStmt(C->getThreadLimit()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPPriorityClause(
      OMPPriorityClause *C) {
    TRY_TO(TraverseStmt(C->getPriority()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPGrainsizeClause(
      OMPGrainsizeClause *C) {
    TRY_TO(TraverseStmt(C->getGrainsize()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPNumTasksClause(
      OMPNumTasksClause *C) {
    TRY_TO(TraverseStmt(C->getNumTasks()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPHintClause(OMPHintClause *C) {
    TRY_TO(TraverseStmt(C->getHint()));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPDistScheduleClause(
      OMPDistScheduleClause *C) {
    TRY_TO(VisitOMPClauseWithPreInit(C));
    TRY_TO(TraverseStmt(C->getChunkSize()));
    return true;
  }
  
  template <typename Derived>
  bool
  RecursiveASTVisitor<Derived>::VisitOMPDefaultmapClause(OMPDefaultmapClause *C) {
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPToClause(OMPToClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPFromClause(OMPFromClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPUseDevicePtrClause(
      OMPUseDevicePtrClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  template <typename Derived>
  bool RecursiveASTVisitor<Derived>::VisitOMPIsDevicePtrClause(
      OMPIsDevicePtrClause *C) {
    TRY_TO(VisitOMPClauseList(C));
    return true;
  }
  
  // FIXME: look at the following tricky-seeming exprs to see if we
  // need to recurse on anything.  These are ones that have methods
  // returning decls or qualtypes or nestednamespecifier -- though I'm
  // not sure if they own them -- or just seemed very complicated, or
  // had lots of sub-types to explore.
  //
  // VisitOverloadExpr and its children: recurse on template args? etc?
  
  // FIXME: go through all the stmts and exprs again, and see which of them
  // create new types, and recurse on the types (TypeLocs?) of those.
  // Candidates:
  //
  //    http://clang.llvm.org/doxygen/classclang_1_1CXXTypeidExpr.html
  //    http://clang.llvm.org/doxygen/classclang_1_1UnaryExprOrTypeTraitExpr.html
  //    http://clang.llvm.org/doxygen/classclang_1_1TypesCompatibleExpr.html
  //    Every class that has getQualifier.
  
  #undef DEF_TRAVERSE_STMT
  #undef TRAVERSE_STMT
  #undef TRAVERSE_STMT_BASE
  
  #undef TRY_TO
  
  } // end namespace clang
  
  #endif // LLVM_CLANG_AST_RECURSIVEASTVISITOR_H
  