xref: /external/clang/include/clang/AST/RecursiveASTVisitor.h

//===--- 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 <type_traits>

#include "clang/AST/Attr.h"
#include "clang/AST/Decl.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/NestedNameSpecifier.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"

// 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(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 (0)

/// \brief A class that does preorder 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.
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.
  typedef SmallVectorImpl<Stmt *> DataRecursionQueue;

  /// \brief Return a reference to the derived class.
  Derived &getDerived() { return *static_cast<Derived *>(this); }

  /// \brief Return whether this visitor should recurse into
  /// template instantiations.
  bool shouldVisitTemplateInstantiations() const { return false; }

  /// \brief Return whether this visitor should recurse into the types of
  /// TypeLocs.
  bool shouldWalkTypesOfTypeLocs() const { return true; }

  /// \brief Return whether this visitor should recurse into implicit
  /// code, e.g., implicit constructors and destructors.
  bool shouldVisitImplicitCode() const { return false; }

  /// \brief 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);

  /// \brief 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);

  /// \brief 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);

  /// \brief 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);

  /// \brief 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);

  /// \brief Recursively visit a C++ nested-name-specifier.
  ///
  /// \returns false if the visitation was terminated early, true otherwise.
  bool TraverseNestedNameSpecifier(NestedNameSpecifier *NNS);

  /// \brief Recursively visit a C++ nested-name-specifier with location
  /// information.
  ///
  /// \returns false if the visitation was terminated early, true otherwise.
  bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS);

  /// \brief Recursively visit a name with its location information.
  ///
  /// \returns false if the visitation was terminated early, true otherwise.
  bool TraverseDeclarationNameInfo(DeclarationNameInfo NameInfo);

  /// \brief 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);

  /// \brief 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);

  /// \brief 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);

  /// \brief 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);

  /// \brief 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);

  /// \brief Recursively visit a lambda capture.
  ///
  /// \returns false if the visitation was terminated early, true otherwise.
  bool TraverseLambdaCapture(LambdaExpr *LE, const LambdaCapture *C);

  /// \brief Recursively visit the body of a lambda expression.
  ///
  /// This provides a hook for visitors that need more context when visiting
  /// \c LE->getBody().
  ///
  /// \returns false if the visitation was terminated early, true otherwise.
  bool TraverseLambdaBody(LambdaExpr *LE, DataRecursionQueue *Queue = nullptr);

  /// \brief 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 ----

  // \brief 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 ----

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 (0)

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) {              \
    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) { \
    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"

private:
  // These are helper methods used by more than one Traverse* method.
  bool TraverseTemplateParameterListHelper(TemplateParameterList *TPL);
#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"
  /// \brief Process clauses with list of variables.
  template <typename T> bool VisitOMPClauseList(T *Node);

  bool dataTraverseNode(Stmt *S, DataRecursionQueue *Queue);
};

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>::TraverseStmt(Stmt *S,
                                                DataRecursionQueue *Queue) {
  if (!S)
    return true;

  if (Queue) {
    Queue->push_back(S);
    return true;
  }

  SmallVector<Stmt *, 8> LocalQueue;
  LocalQueue.push_back(S);

  while (!LocalQueue.empty()) {
    Stmt *CurrS = LocalQueue.pop_back_val();

    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());
  }

  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::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) {
  if (LE->isInitCapture(C))
    TRY_TO(TraverseDecl(C->getCapturedVar()));
  return true;
}

template <typename Derived>
bool RecursiveASTVisitor<Derived>::TraverseLambdaBody(
    LambdaExpr *LE, DataRecursionQueue *Queue) {
  TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(LE->getBody());
  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) {                 \
    TRY_TO(WalkUpFrom##TYPE(T));                                               \
    { CODE; }                                                                  \
    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(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(RecordType, {})
DEF_TRAVERSE_TYPE(EnumType, {})
DEF_TRAVERSE_TYPE(TemplateTypeParmType, {})
DEF_TRAVERSE_TYPE(SubstTemplateTypeParmType, {})
DEF_TRAVERSE_TYPE(SubstTemplateTypeParmPackType, {})

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(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())); })

#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);
})

// 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()));
})

// 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(RecordType, {})
DEF_TRAVERSE_TYPELOC(EnumType, {})
DEF_TRAVERSE_TYPELOC(TemplateTypeParmType, {})
DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmType, {})
DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmPackType, {})

// 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(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())); })

#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>::TraverseDeclContextHelper(DeclContext *DC) {
  if (!DC)
    return true;

  for (auto *Child : DC->decls()) {
    // BlockDecls and CapturedDecls are traversed through BlockExprs and
    // CapturedStmts respectively.
    if (!isa<BlockDecl>(Child) && !isa<CapturedDecl>(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) {                 \
    TRY_TO(WalkUpFrom##DECL(D));                                               \
    { CODE; }                                                                  \
    TRY_TO(TraverseDeclContextHelper(dyn_cast<DeclContext>(D)));               \
    return true;                                                               \
  }

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()));
    }
  }
  // This return statement makes sure the traversal of nodes in
  // decls_begin()/decls_end() (done in the DEF_TRAVERSE_DECL macro)
  // is skipped - don't remove it.
  return true;
})

DEF_TRAVERSE_DECL(CapturedDecl, {
  TRY_TO(TraverseStmt(D->getBody()));
  // This return statement makes sure the traversal of nodes in
  // decls_begin()/decls_end() (done in the DEF_TRAVERSE_DECL macro)
  // is skipped - don't remove it.
  return true;
})

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(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(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.
  //
  // This return statement makes sure the traversal of nodes in
  // decls_begin()/decls_end() (done in the DEF_TRAVERSE_DECL macro)
  // is skipped - don't remove it.
  return true;
})

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 (ObjCMethodDecl::param_iterator I = D->param_begin(), E = D->param_end();
       I != E; ++I) {
    TRY_TO(TraverseDecl(*I));
  }
  if (D->isThisDeclarationADefinition()) {
    TRY_TO(TraverseStmt(D->getBody()));
  }
  return true;
})

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()));
  return true;
})

DEF_TRAVERSE_DECL(UsingDecl, {
  TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
  TRY_TO(TraverseDeclarationNameInfo(D->getNameInfo()));
})

DEF_TRAVERSE_DECL(UsingDirectiveDecl, {
  TRY_TO(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
})

DEF_TRAVERSE_DECL(UsingShadowDecl, {})

DEF_TRAVERSE_DECL(OMPThreadPrivateDecl, {
  for (auto *I : D->varlists()) {
    TRY_TO(TraverseStmt(I));
  }
})

// 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>
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(TraverseDecl(D->getTemplatedDecl()));                               \
    TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));   \
                                                                               \
    /* 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, {
  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(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
  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(TraverseTypeLoc(I.getTypeSourceInfo()->getTypeLoc()));
    }
    // 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()));                              \
                                                                               \
    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(TraverseNestedNameSpecifierLoc(D->getQualifierLoc()));
  if (D->getTypeSourceInfo())
    TRY_TO(TraverseTypeLoc(D->getTypeSourceInfo()->getTypeLoc()));
  else
    TRY_TO(TraverseType(D->getType()));
  return true;
}

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(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 (FunctionDecl::param_const_iterator I = D->param_begin(),
                                            E = D->param_end();
         I != E; ++I)
      TRY_TO(TraverseDecl(*I));
  }

  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().
  return TraverseFunctionHelper(D);
})

DEF_TRAVERSE_DECL(CXXMethodDecl, {
  // We skip decls_begin/decls_end, which are already covered by
  // TraverseFunctionHelper().
  return TraverseFunctionHelper(D);
})

DEF_TRAVERSE_DECL(CXXConstructorDecl, {
  // We skip decls_begin/decls_end, which are already covered by
  // TraverseFunctionHelper().
  return 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().
  return TraverseFunctionHelper(D);
})

DEF_TRAVERSE_DECL(CXXDestructorDecl, {
  // We skip decls_begin/decls_end, which are already covered by
  // TraverseFunctionHelper().
  return 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) {                                    \
    TRY_TO(WalkUpFrom##STMT(S));                                               \
    { CODE; }                                                                  \
    for (Stmt *SubStmt : S->children()) {                                      \
      TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(SubStmt);                                          \
    }                                                                          \
    return true;                                                               \
  }

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).
  return true;
})

// 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()) {
    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().
    return true;
  }
})
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(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->getExplicitTemplateArgs().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) {
    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.
DEF_TRAVERSE_STMT(InitListExpr, {
  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));
  }
  return true;
})

// 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);
  }
  return true;
})

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, {
  for (LambdaExpr::capture_iterator C = S->explicit_capture_begin(),
                                    CEnd = S->explicit_capture_end();
       C != CEnd; ++C) {
    TRY_TO(TraverseLambdaCapture(S, C));
  }

  TypeLoc TL = S->getCallOperator()->getTypeSourceInfo()->getTypeLoc();
  FunctionProtoTypeLoc Proto = TL.castAs<FunctionProtoTypeLoc>();

  if (S->hasExplicitParameters() && S->hasExplicitResultType()) {
    // Visit the whole type.
    TRY_TO(TraverseTypeLoc(TL));
  } else {
    if (S->hasExplicitParameters()) {
      // Visit parameters.
      for (unsigned I = 0, N = Proto.getNumParams(); I != N; ++I) {
        TRY_TO(TraverseDecl(Proto.getParam(I)));
      }
    } else 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);
  }

  return TRAVERSE_STMT_BASE(LambdaBody, LambdaExpr, S, Queue);
})

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, {})
DEF_TRAVERSE_STMT(CXXDefaultInitExpr, {})
DEF_TRAVERSE_STMT(CXXDeleteExpr, {})
DEF_TRAVERSE_STMT(ExprWithCleanups, {})
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(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(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());
    return true;
  }
})
DEF_TRAVERSE_STMT(CoreturnStmt, {
  if (!getDerived().shouldVisitImplicitCode()) {
    TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOperand());
    return true;
  }
})
DEF_TRAVERSE_STMT(CoawaitExpr, {
  if (!getDerived().shouldVisitImplicitCode()) {
    TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOperand());
    return true;
  }
})
DEF_TRAVERSE_STMT(CoyieldExpr, {
  if (!getDerived().shouldVisitImplicitCode()) {
    TRY_TO_TRAVERSE_OR_ENQUEUE_STMT(S->getOperand());
    return true;
  }
})

// These literals (all of them) do not need any action.
DEF_TRAVERSE_STMT(IntegerLiteral, {})
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(OMPTeamsDirective,
                  { 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)); })

// 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_unknown:
    break;
  }
  return true;
}

template <typename Derived>
bool RecursiveASTVisitor<Derived>::VisitOMPIfClause(OMPIfClause *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(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>::VisitOMPScheduleClause(OMPScheduleClause *C) {
  TRY_TO(TraverseStmt(C->getChunkSize()));
  TRY_TO(TraverseStmt(C->getHelperChunkSize()));
  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));
  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));
  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));
  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));
  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>::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(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(TraverseStmt(C->getNumTeams()));
  return true;
}

template <typename Derived>
bool RecursiveASTVisitor<Derived>::VisitOMPThreadLimitClause(
    OMPThreadLimitClause *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;
}

// 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