Add the clang library to the repo (with some of my changes, too).

1 files changed, 9268 insertions, 0 deletions

diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
new file mode 100644
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+++ b/clang/lib/Sema/TreeTransform.h
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+//===------- TreeTransform.h - Semantic Tree Transformation -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//===----------------------------------------------------------------------===//
+//
+//  This file implements a semantic tree transformation that takes a given
+//  AST and rebuilds it, possibly transforming some nodes in the process.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SEMA_TREETRANSFORM_H
+#define LLVM_CLANG_SEMA_TREETRANSFORM_H
+
+#include "clang/Sema/SemaInternal.h"
+#include "clang/Sema/Lookup.h"
+#include "clang/Sema/ParsedTemplate.h"
+#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/Sema/ScopeInfo.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ExprObjC.h"
+#include "clang/AST/Stmt.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/AST/StmtObjC.h"
+#include "clang/Sema/Ownership.h"
+#include "clang/Sema/Designator.h"
+#include "clang/Lex/Preprocessor.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "TypeLocBuilder.h"
+#include <algorithm>
+
+namespace clang {
+using namespace sema;
+
+/// \brief A semantic tree transformation that allows one to transform one
+/// abstract syntax tree into another.
+///
+/// A new tree transformation is defined by creating a new subclass \c X of
+/// \c TreeTransform<X> and then overriding certain operations to provide
+/// behavior specific to that transformation. For example, template
+/// instantiation is implemented as a tree transformation where the
+/// transformation of TemplateTypeParmType nodes involves substituting the
+/// template arguments for their corresponding template parameters; a similar
+/// transformation is performed for non-type template parameters and
+/// template template parameters.
+///
+/// This tree-transformation template uses static polymorphism to allow
+/// subclasses to customize any of its operations. Thus, a subclass can
+/// override any of the transformation or rebuild operators by providing an
+/// operation with the same signature as the default implementation. The
+/// overridding function should not be virtual.
+///
+/// Semantic tree transformations are split into two stages, either of which
+/// can be replaced by a subclass. The "transform" step transforms an AST node
+/// or the parts of an AST node using the various transformation functions,
+/// then passes the pieces on to the "rebuild" step, which constructs a new AST
+/// node of the appropriate kind from the pieces. The default transformation
+/// routines recursively transform the operands to composite AST nodes (e.g.,
+/// the pointee type of a PointerType node) and, if any of those operand nodes
+/// were changed by the transformation, invokes the rebuild operation to create
+/// a new AST node.
+///
+/// Subclasses can customize the transformation at various levels. The
+/// most coarse-grained transformations involve replacing TransformType(),
+/// TransformExpr(), TransformDecl(), TransformNestedNameSpecifierLoc(),
+/// TransformTemplateName(), or TransformTemplateArgument() with entirely
+/// new implementations.
+///
+/// For more fine-grained transformations, subclasses can replace any of the
+/// \c TransformXXX functions (where XXX is the name of an AST node, e.g.,
+/// PointerType, StmtExpr) to alter the transformation. As mentioned previously,
+/// replacing TransformTemplateTypeParmType() allows template instantiation
+/// to substitute template arguments for their corresponding template
+/// parameters. Additionally, subclasses can override the \c RebuildXXX
+/// functions to control how AST nodes are rebuilt when their operands change.
+/// By default, \c TreeTransform will invoke semantic analysis to rebuild
+/// AST nodes. However, certain other tree transformations (e.g, cloning) may
+/// be able to use more efficient rebuild steps.
+///
+/// There are a handful of other functions that can be overridden, allowing one
+/// to avoid traversing nodes that don't need any transformation
+/// (\c AlreadyTransformed()), force rebuilding AST nodes even when their
+/// operands have not changed (\c AlwaysRebuild()), and customize the
+/// default locations and entity names used for type-checking
+/// (\c getBaseLocation(), \c getBaseEntity()).
+template<typename Derived>
+class TreeTransform {
+  /// \brief Private RAII object that helps us forget and then re-remember
+  /// the template argument corresponding to a partially-substituted parameter
+  /// pack.
+  class ForgetPartiallySubstitutedPackRAII {
+    Derived &Self;
+    TemplateArgument Old;
+    
+  public:
+    ForgetPartiallySubstitutedPackRAII(Derived &Self) : Self(Self) {
+      Old = Self.ForgetPartiallySubstitutedPack();
+    }
+    
+    ~ForgetPartiallySubstitutedPackRAII() {
+      Self.RememberPartiallySubstitutedPack(Old);
+    }
+  };
+  
+protected:
+  Sema &SemaRef;
+  
+  /// \brief The set of local declarations that have been transformed, for
+  /// cases where we are forced to build new declarations within the transformer
+  /// rather than in the subclass (e.g., lambda closure types).
+  llvm::DenseMap<Decl *, Decl *> TransformedLocalDecls;
+  
+public:
+  /// \brief Initializes a new tree transformer.
+  TreeTransform(Sema &SemaRef) : SemaRef(SemaRef) { }
+
+  /// \brief Retrieves a reference to the derived class.
+  Derived &getDerived() { return static_cast<Derived&>(*this); }
+
+  /// \brief Retrieves a reference to the derived class.
+  const Derived &getDerived() const {
+    return static_cast<const Derived&>(*this);
+  }
+
+  static inline ExprResult Owned(Expr *E) { return E; }
+  static inline StmtResult Owned(Stmt *S) { return S; }
+
+  /// \brief Retrieves a reference to the semantic analysis object used for
+  /// this tree transform.
+  Sema &getSema() const { return SemaRef; }
+
+  /// \brief Whether the transformation should always rebuild AST nodes, even
+  /// if none of the children have changed.
+  ///
+  /// Subclasses may override this function to specify when the transformation
+  /// should rebuild all AST nodes.
+  bool AlwaysRebuild() { return false; }
+
+  /// \brief Returns the location of the entity being transformed, if that
+  /// information was not available elsewhere in the AST.
+  ///
+  /// By default, returns no source-location information. Subclasses can
+  /// provide an alternative implementation that provides better location
+  /// information.
+  SourceLocation getBaseLocation() { return SourceLocation(); }
+
+  /// \brief Returns the name of the entity being transformed, if that
+  /// information was not available elsewhere in the AST.
+  ///
+  /// By default, returns an empty name. Subclasses can provide an alternative
+  /// implementation with a more precise name.
+  DeclarationName getBaseEntity() { return DeclarationName(); }
+
+  /// \brief Sets the "base" location and entity when that
+  /// information is known based on another transformation.
+  ///
+  /// By default, the source location and entity are ignored. Subclasses can
+  /// override this function to provide a customized implementation.
+  void setBase(SourceLocation Loc, DeclarationName Entity) { }
+
+  /// \brief RAII object that temporarily sets the base location and entity
+  /// used for reporting diagnostics in types.
+  class TemporaryBase {
+    TreeTransform &Self;
+    SourceLocation OldLocation;
+    DeclarationName OldEntity;
+
+  public:
+    TemporaryBase(TreeTransform &Self, SourceLocation Location,
+                  DeclarationName Entity) : Self(Self) {
+      OldLocation = Self.getDerived().getBaseLocation();
+      OldEntity = Self.getDerived().getBaseEntity();
+      
+      if (Location.isValid())
+        Self.getDerived().setBase(Location, Entity);
+    }
+
+    ~TemporaryBase() {
+      Self.getDerived().setBase(OldLocation, OldEntity);
+    }
+  };
+
+  /// \brief Determine whether the given type \p T has already been
+  /// transformed.
+  ///
+  /// Subclasses can provide an alternative implementation of this routine
+  /// to short-circuit evaluation when it is known that a given type will
+  /// not change. For example, template instantiation need not traverse
+  /// non-dependent types.
+  bool AlreadyTransformed(QualType T) {
+    return T.isNull();
+  }
+
+  /// \brief Determine whether the given call argument should be dropped, e.g.,
+  /// because it is a default argument.
+  ///
+  /// Subclasses can provide an alternative implementation of this routine to
+  /// determine which kinds of call arguments get dropped. By default,
+  /// CXXDefaultArgument nodes are dropped (prior to transformation).
+  bool DropCallArgument(Expr *E) {
+    return E->isDefaultArgument();
+  }
+  
+  /// \brief Determine whether we should expand a pack expansion with the
+  /// given set of parameter packs into separate arguments by repeatedly
+  /// transforming the pattern.
+  ///
+  /// By default, the transformer never tries to expand pack expansions.
+  /// Subclasses can override this routine to provide different behavior.
+  ///
+  /// \param EllipsisLoc The location of the ellipsis that identifies the
+  /// pack expansion.
+  ///
+  /// \param PatternRange The source range that covers the entire pattern of
+  /// the pack expansion.
+  ///
+  /// \param Unexpanded The set of unexpanded parameter packs within the 
+  /// pattern.
+  ///
+  /// \param NumUnexpanded The number of unexpanded parameter packs in
+  /// \p Unexpanded.
+  ///
+  /// \param ShouldExpand Will be set to \c true if the transformer should
+  /// expand the corresponding pack expansions into separate arguments. When
+  /// set, \c NumExpansions must also be set.
+  ///
+  /// \param RetainExpansion Whether the caller should add an unexpanded
+  /// pack expansion after all of the expanded arguments. This is used
+  /// when extending explicitly-specified template argument packs per
+  /// C++0x [temp.arg.explicit]p9.
+  ///
+  /// \param NumExpansions The number of separate arguments that will be in
+  /// the expanded form of the corresponding pack expansion. This is both an
+  /// input and an output parameter, which can be set by the caller if the
+  /// number of expansions is known a priori (e.g., due to a prior substitution)
+  /// and will be set by the callee when the number of expansions is known.
+  /// The callee must set this value when \c ShouldExpand is \c true; it may
+  /// set this value in other cases.
+  ///
+  /// \returns true if an error occurred (e.g., because the parameter packs 
+  /// are to be instantiated with arguments of different lengths), false 
+  /// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions) 
+  /// must be set.
+  bool TryExpandParameterPacks(SourceLocation EllipsisLoc,
+                               SourceRange PatternRange,
+                             llvm::ArrayRef<UnexpandedParameterPack> Unexpanded,
+                               bool &ShouldExpand,
+                               bool &RetainExpansion,
+                               llvm::Optional<unsigned> &NumExpansions) {
+    ShouldExpand = false;
+    return false;
+  }
+  
+  /// \brief "Forget" about the partially-substituted pack template argument,
+  /// when performing an instantiation that must preserve the parameter pack
+  /// use.
+  ///
+  /// This routine is meant to be overridden by the template instantiator.
+  TemplateArgument ForgetPartiallySubstitutedPack() {
+    return TemplateArgument();
+  }
+  
+  /// \brief "Remember" the partially-substituted pack template argument
+  /// after performing an instantiation that must preserve the parameter pack
+  /// use.
+  ///
+  /// This routine is meant to be overridden by the template instantiator.
+  void RememberPartiallySubstitutedPack(TemplateArgument Arg) { }
+  
+  /// \brief Note to the derived class when a function parameter pack is
+  /// being expanded.
+  void ExpandingFunctionParameterPack(ParmVarDecl *Pack) { }
+                                      
+  /// \brief Transforms the given type into another type.
+  ///
+  /// By default, this routine transforms a type by creating a
+  /// TypeSourceInfo for it and delegating to the appropriate
+  /// function.  This is expensive, but we don't mind, because
+  /// this method is deprecated anyway;  all users should be
+  /// switched to storing TypeSourceInfos.
+  ///
+  /// \returns the transformed type.
+  QualType TransformType(QualType T);
+
+  /// \brief Transforms the given type-with-location into a new
+  /// type-with-location.
+  ///
+  /// By default, this routine transforms a type by delegating to the
+  /// appropriate TransformXXXType to build a new type.  Subclasses
+  /// may override this function (to take over all type
+  /// transformations) or some set of the TransformXXXType functions
+  /// to alter the transformation.
+  TypeSourceInfo *TransformType(TypeSourceInfo *DI);
+
+  /// \brief Transform the given type-with-location into a new
+  /// type, collecting location information in the given builder
+  /// as necessary.
+  ///
+  QualType TransformType(TypeLocBuilder &TLB, TypeLoc TL);
+
+  /// \brief Transform the given statement.
+  ///
+  /// By default, this routine transforms a statement by delegating to the
+  /// appropriate TransformXXXStmt function to transform a specific kind of
+  /// statement or the TransformExpr() function to transform an expression.
+  /// Subclasses may override this function to transform statements using some
+  /// other mechanism.
+  ///
+  /// \returns the transformed statement.
+  StmtResult TransformStmt(Stmt *S);
+
+  /// \brief Transform the given expression.
+  ///
+  /// By default, this routine transforms an expression by delegating to the
+  /// appropriate TransformXXXExpr function to build a new expression.
+  /// Subclasses may override this function to transform expressions using some
+  /// other mechanism.
+  ///
+  /// \returns the transformed expression.
+  ExprResult TransformExpr(Expr *E);
+
+  /// \brief Transform the given list of expressions.
+  ///
+  /// This routine transforms a list of expressions by invoking 
+  /// \c TransformExpr() for each subexpression. However, it also provides 
+  /// support for variadic templates by expanding any pack expansions (if the
+  /// derived class permits such expansion) along the way. When pack expansions
+  /// are present, the number of outputs may not equal the number of inputs.
+  ///
+  /// \param Inputs The set of expressions to be transformed.
+  ///
+  /// \param NumInputs The number of expressions in \c Inputs.
+  ///
+  /// \param IsCall If \c true, then this transform is being performed on
+  /// function-call arguments, and any arguments that should be dropped, will 
+  /// be.
+  ///
+  /// \param Outputs The transformed input expressions will be added to this
+  /// vector.
+  ///
+  /// \param ArgChanged If non-NULL, will be set \c true if any argument changed
+  /// due to transformation.
+  ///
+  /// \returns true if an error occurred, false otherwise.
+  bool TransformExprs(Expr **Inputs, unsigned NumInputs, bool IsCall,
+                      SmallVectorImpl<Expr *> &Outputs,
+                      bool *ArgChanged = 0);
+  
+  /// \brief Transform the given declaration, which is referenced from a type
+  /// or expression.
+  ///
+  /// By default, acts as the identity function on declarations, unless the
+  /// transformer has had to transform the declaration itself. Subclasses
+  /// may override this function to provide alternate behavior.
+  Decl *TransformDecl(SourceLocation Loc, Decl *D) { 
+    llvm::DenseMap<Decl *, Decl *>::iterator Known
+      = TransformedLocalDecls.find(D);
+    if (Known != TransformedLocalDecls.end())
+      return Known->second;
+    
+    return D; 
+  }
+
+  /// \brief Transform the attributes associated with the given declaration and 
+  /// place them on the new declaration.
+  ///
+  /// By default, this operation does nothing. Subclasses may override this
+  /// behavior to transform attributes.
+  void transformAttrs(Decl *Old, Decl *New) { }
+  
+  /// \brief Note that a local declaration has been transformed by this
+  /// transformer.
+  ///
+  /// Local declarations are typically transformed via a call to 
+  /// TransformDefinition. However, in some cases (e.g., lambda expressions),
+  /// the transformer itself has to transform the declarations. This routine
+  /// can be overridden by a subclass that keeps track of such mappings.
+  void transformedLocalDecl(Decl *Old, Decl *New) {
+    TransformedLocalDecls[Old] = New;
+  }
+  
+  /// \brief Transform the definition of the given declaration.
+  ///
+  /// By default, invokes TransformDecl() to transform the declaration.
+  /// Subclasses may override this function to provide alternate behavior.
+  Decl *TransformDefinition(SourceLocation Loc, Decl *D) { 
+    return getDerived().TransformDecl(Loc, D); 
+  }
+
+  /// \brief Transform the given declaration, which was the first part of a
+  /// nested-name-specifier in a member access expression.
+  ///
+  /// This specific declaration transformation only applies to the first 
+  /// identifier in a nested-name-specifier of a member access expression, e.g.,
+  /// the \c T in \c x->T::member
+  ///
+  /// By default, invokes TransformDecl() to transform the declaration.
+  /// Subclasses may override this function to provide alternate behavior.
+  NamedDecl *TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc) { 
+    return cast_or_null<NamedDecl>(getDerived().TransformDecl(Loc, D)); 
+  }
+  
+  /// \brief Transform the given nested-name-specifier with source-location
+  /// information.
+  ///
+  /// By default, transforms all of the types and declarations within the
+  /// nested-name-specifier. Subclasses may override this function to provide
+  /// alternate behavior.
+  NestedNameSpecifierLoc TransformNestedNameSpecifierLoc(
+                                                    NestedNameSpecifierLoc NNS,
+                                          QualType ObjectType = QualType(),
+                                          NamedDecl *FirstQualifierInScope = 0);
+
+  /// \brief Transform the given declaration name.
+  ///
+  /// By default, transforms the types of conversion function, constructor,
+  /// and destructor names and then (if needed) rebuilds the declaration name.
+  /// Identifiers and selectors are returned unmodified. Sublcasses may
+  /// override this function to provide alternate behavior.
+  DeclarationNameInfo
+  TransformDeclarationNameInfo(const DeclarationNameInfo &NameInfo);
+
+  /// \brief Transform the given template name.
+  ///
+  /// \param SS The nested-name-specifier that qualifies the template
+  /// name. This nested-name-specifier must already have been transformed.
+  ///
+  /// \param Name The template name to transform.
+  ///
+  /// \param NameLoc The source location of the template name.
+  ///
+  /// \param ObjectType If we're translating a template name within a member 
+  /// access expression, this is the type of the object whose member template
+  /// is being referenced.
+  ///
+  /// \param FirstQualifierInScope If the first part of a nested-name-specifier
+  /// also refers to a name within the current (lexical) scope, this is the
+  /// declaration it refers to.
+  ///
+  /// By default, transforms the template name by transforming the declarations
+  /// and nested-name-specifiers that occur within the template name.
+  /// Subclasses may override this function to provide alternate behavior.
+  TemplateName TransformTemplateName(CXXScopeSpec &SS,
+                                     TemplateName Name,
+                                     SourceLocation NameLoc,
+                                     QualType ObjectType = QualType(),
+                                     NamedDecl *FirstQualifierInScope = 0);
+
+  /// \brief Transform the given template argument.
+  ///
+  /// By default, this operation transforms the type, expression, or
+  /// declaration stored within the template argument and constructs a
+  /// new template argument from the transformed result. Subclasses may
+  /// override this function to provide alternate behavior.
+  ///
+  /// Returns true if there was an error.
+  bool TransformTemplateArgument(const TemplateArgumentLoc &Input,
+                                 TemplateArgumentLoc &Output);
+
+  /// \brief Transform the given set of template arguments.
+  ///
+  /// By default, this operation transforms all of the template arguments 
+  /// in the input set using \c TransformTemplateArgument(), and appends
+  /// the transformed arguments to the output list.
+  ///
+  /// Note that this overload of \c TransformTemplateArguments() is merely
+  /// a convenience function. Subclasses that wish to override this behavior
+  /// should override the iterator-based member template version.
+  ///
+  /// \param Inputs The set of template arguments to be transformed.
+  ///
+  /// \param NumInputs The number of template arguments in \p Inputs.
+  ///
+  /// \param Outputs The set of transformed template arguments output by this
+  /// routine.
+  ///
+  /// Returns true if an error occurred.
+  bool TransformTemplateArguments(const TemplateArgumentLoc *Inputs,
+                                  unsigned NumInputs,
+                                  TemplateArgumentListInfo &Outputs) {
+    return TransformTemplateArguments(Inputs, Inputs + NumInputs, Outputs);
+  }
+
+  /// \brief Transform the given set of template arguments.
+  ///
+  /// By default, this operation transforms all of the template arguments 
+  /// in the input set using \c TransformTemplateArgument(), and appends
+  /// the transformed arguments to the output list. 
+  ///
+  /// \param First An iterator to the first template argument.
+  ///
+  /// \param Last An iterator one step past the last template argument.
+  ///
+  /// \param Outputs The set of transformed template arguments output by this
+  /// routine.
+  ///
+  /// Returns true if an error occurred.
+  template<typename InputIterator>
+  bool TransformTemplateArguments(InputIterator First,
+                                  InputIterator Last,
+                                  TemplateArgumentListInfo &Outputs);
+
+  /// \brief Fakes up a TemplateArgumentLoc for a given TemplateArgument.
+  void InventTemplateArgumentLoc(const TemplateArgument &Arg,
+                                 TemplateArgumentLoc &ArgLoc);
+
+  /// \brief Fakes up a TypeSourceInfo for a type.
+  TypeSourceInfo *InventTypeSourceInfo(QualType T) {
+    return SemaRef.Context.getTrivialTypeSourceInfo(T,
+                       getDerived().getBaseLocation());
+  }
+
+#define ABSTRACT_TYPELOC(CLASS, PARENT)
+#define TYPELOC(CLASS, PARENT)                                   \
+  QualType Transform##CLASS##Type(TypeLocBuilder &TLB, CLASS##TypeLoc T);
+#include "clang/AST/TypeLocNodes.def"
+
+  QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
+                                      FunctionProtoTypeLoc TL,
+                                      CXXRecordDecl *ThisContext,
+                                      unsigned ThisTypeQuals);
+
+  StmtResult
+  TransformSEHHandler(Stmt *Handler);
+
+  QualType 
+  TransformTemplateSpecializationType(TypeLocBuilder &TLB,
+                                      TemplateSpecializationTypeLoc TL,
+                                      TemplateName Template);
+
+  QualType 
+  TransformDependentTemplateSpecializationType(TypeLocBuilder &TLB,
+                                      DependentTemplateSpecializationTypeLoc TL,
+                                               TemplateName Template,
+                                               CXXScopeSpec &SS);
+
+  QualType 
+  TransformDependentTemplateSpecializationType(TypeLocBuilder &TLB,
+                                               DependentTemplateSpecializationTypeLoc TL,
+                                         NestedNameSpecifierLoc QualifierLoc);
+
+  /// \brief Transforms the parameters of a function type into the
+  /// given vectors.
+  ///
+  /// The result vectors should be kept in sync; null entries in the
+  /// variables vector are acceptable.
+  ///
+  /// Return true on error.
+  bool TransformFunctionTypeParams(SourceLocation Loc,
+                                   ParmVarDecl **Params, unsigned NumParams,
+                                   const QualType *ParamTypes,
+                                   SmallVectorImpl<QualType> &PTypes,
+                                   SmallVectorImpl<ParmVarDecl*> *PVars);
+
+  /// \brief Transforms a single function-type parameter.  Return null
+  /// on error.
+  ///
+  /// \param indexAdjustment - A number to add to the parameter's
+  ///   scope index;  can be negative
+  ParmVarDecl *TransformFunctionTypeParam(ParmVarDecl *OldParm,
+                                          int indexAdjustment,
+                                        llvm::Optional<unsigned> NumExpansions,
+                                          bool ExpectParameterPack);
+
+  QualType TransformReferenceType(TypeLocBuilder &TLB, ReferenceTypeLoc TL);
+
+  StmtResult TransformCompoundStmt(CompoundStmt *S, bool IsStmtExpr);
+  ExprResult TransformCXXNamedCastExpr(CXXNamedCastExpr *E);
+
+#define STMT(Node, Parent)                        \
+  StmtResult Transform##Node(Node *S);
+#define EXPR(Node, Parent)                        \
+  ExprResult Transform##Node(Node *E);
+#define ABSTRACT_STMT(Stmt)
+#include "clang/AST/StmtNodes.inc"
+
+  /// \brief Build a new pointer type given its pointee type.
+  ///
+  /// By default, performs semantic analysis when building the pointer type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildPointerType(QualType PointeeType, SourceLocation Sigil);
+
+  /// \brief Build a new block pointer type given its pointee type.
+  ///
+  /// By default, performs semantic analysis when building the block pointer
+  /// type. Subclasses may override this routine to provide different behavior.
+  QualType RebuildBlockPointerType(QualType PointeeType, SourceLocation Sigil);
+
+  /// \brief Build a new reference type given the type it references.
+  ///
+  /// By default, performs semantic analysis when building the
+  /// reference type. Subclasses may override this routine to provide
+  /// different behavior.
+  ///
+  /// \param LValue whether the type was written with an lvalue sigil
+  /// or an rvalue sigil.
+  QualType RebuildReferenceType(QualType ReferentType,
+                                bool LValue,
+                                SourceLocation Sigil);
+
+  /// \brief Build a new member pointer type given the pointee type and the
+  /// class type it refers into.
+  ///
+  /// By default, performs semantic analysis when building the member pointer
+  /// type. Subclasses may override this routine to provide different behavior.
+  QualType RebuildMemberPointerType(QualType PointeeType, QualType ClassType,
+                                    SourceLocation Sigil);
+
+  /// \brief Build a new array type given the element type, size
+  /// modifier, size of the array (if known), size expression, and index type
+  /// qualifiers.
+  ///
+  /// By default, performs semantic analysis when building the array type.
+  /// Subclasses may override this routine to provide different behavior.
+  /// Also by default, all of the other Rebuild*Array
+  QualType RebuildArrayType(QualType ElementType,
+                            ArrayType::ArraySizeModifier SizeMod,
+                            const llvm::APInt *Size,
+                            Expr *SizeExpr,
+                            unsigned IndexTypeQuals,
+                            SourceRange BracketsRange);
+
+  /// \brief Build a new constant array type given the element type, size
+  /// modifier, (known) size of the array, and index type qualifiers.
+  ///
+  /// By default, performs semantic analysis when building the array type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildConstantArrayType(QualType ElementType,
+                                    ArrayType::ArraySizeModifier SizeMod,
+                                    const llvm::APInt &Size,
+                                    unsigned IndexTypeQuals,
+                                    SourceRange BracketsRange);
+
+  /// \brief Build a new incomplete array type given the element type, size
+  /// modifier, and index type qualifiers.
+  ///
+  /// By default, performs semantic analysis when building the array type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildIncompleteArrayType(QualType ElementType,
+                                      ArrayType::ArraySizeModifier SizeMod,
+                                      unsigned IndexTypeQuals,
+                                      SourceRange BracketsRange);
+
+  /// \brief Build a new variable-length array type given the element type,
+  /// size modifier, size expression, and index type qualifiers.
+  ///
+  /// By default, performs semantic analysis when building the array type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildVariableArrayType(QualType ElementType,
+                                    ArrayType::ArraySizeModifier SizeMod,
+                                    Expr *SizeExpr,
+                                    unsigned IndexTypeQuals,
+                                    SourceRange BracketsRange);
+
+  /// \brief Build a new dependent-sized array type given the element type,
+  /// size modifier, size expression, and index type qualifiers.
+  ///
+  /// By default, performs semantic analysis when building the array type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildDependentSizedArrayType(QualType ElementType,
+                                          ArrayType::ArraySizeModifier SizeMod,
+                                          Expr *SizeExpr,
+                                          unsigned IndexTypeQuals,
+                                          SourceRange BracketsRange);
+
+  /// \brief Build a new vector type given the element type and
+  /// number of elements.
+  ///
+  /// By default, performs semantic analysis when building the vector type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildVectorType(QualType ElementType, unsigned NumElements,
+                             VectorType::VectorKind VecKind);
+
+  /// \brief Build a new extended vector type given the element type and
+  /// number of elements.
+  ///
+  /// By default, performs semantic analysis when building the vector type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildExtVectorType(QualType ElementType, unsigned NumElements,
+                                SourceLocation AttributeLoc);
+
+  /// \brief Build a new potentially dependently-sized extended vector type
+  /// given the element type and number of elements.
+  ///
+  /// By default, performs semantic analysis when building the vector type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildDependentSizedExtVectorType(QualType ElementType,
+                                              Expr *SizeExpr,
+                                              SourceLocation AttributeLoc);
+
+  /// \brief Build a new function type.
+  ///
+  /// By default, performs semantic analysis when building the function type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildFunctionProtoType(QualType T,
+                                    QualType *ParamTypes,
+                                    unsigned NumParamTypes,
+                                    bool Variadic, bool HasTrailingReturn,
+                                    unsigned Quals,
+                                    RefQualifierKind RefQualifier,
+                                    const FunctionType::ExtInfo &Info);
+
+  /// \brief Build a new unprototyped function type.
+  QualType RebuildFunctionNoProtoType(QualType ResultType);
+
+  /// \brief Rebuild an unresolved typename type, given the decl that
+  /// the UnresolvedUsingTypenameDecl was transformed to.
+  QualType RebuildUnresolvedUsingType(Decl *D);
+
+  /// \brief Build a new typedef type.
+  QualType RebuildTypedefType(TypedefNameDecl *Typedef) {
+    return SemaRef.Context.getTypeDeclType(Typedef);
+  }
+
+  /// \brief Build a new class/struct/union type.
+  QualType RebuildRecordType(RecordDecl *Record) {
+    return SemaRef.Context.getTypeDeclType(Record);
+  }
+
+  /// \brief Build a new Enum type.
+  QualType RebuildEnumType(EnumDecl *Enum) {
+    return SemaRef.Context.getTypeDeclType(Enum);
+  }
+
+  /// \brief Build a new typeof(expr) type.
+  ///
+  /// By default, performs semantic analysis when building the typeof type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildTypeOfExprType(Expr *Underlying, SourceLocation Loc);
+
+  /// \brief Build a new typeof(type) type.
+  ///
+  /// By default, builds a new TypeOfType with the given underlying type.
+  QualType RebuildTypeOfType(QualType Underlying);
+
+  /// \brief Build a new unary transform type.
+  QualType RebuildUnaryTransformType(QualType BaseType,
+                                     UnaryTransformType::UTTKind UKind,
+                                     SourceLocation Loc);
+
+  /// \brief Build a new C++0x decltype type.
+  ///
+  /// By default, performs semantic analysis when building the decltype type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildDecltypeType(Expr *Underlying, SourceLocation Loc);
+
+  /// \brief Build a new C++0x auto type.
+  ///
+  /// By default, builds a new AutoType with the given deduced type.
+  QualType RebuildAutoType(QualType Deduced) {
+    return SemaRef.Context.getAutoType(Deduced);
+  }
+
+  /// \brief Build a new template specialization type.
+  ///
+  /// By default, performs semantic analysis when building the template
+  /// specialization type. Subclasses may override this routine to provide
+  /// different behavior.
+  QualType RebuildTemplateSpecializationType(TemplateName Template,
+                                             SourceLocation TemplateLoc,
+                                             TemplateArgumentListInfo &Args);
+
+  /// \brief Build a new parenthesized type.
+  ///
+  /// By default, builds a new ParenType type from the inner type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildParenType(QualType InnerType) {
+    return SemaRef.Context.getParenType(InnerType);
+  }
+
+  /// \brief Build a new qualified name type.
+  ///
+  /// By default, builds a new ElaboratedType type from the keyword,
+  /// the nested-name-specifier and the named type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildElaboratedType(SourceLocation KeywordLoc,
+                                 ElaboratedTypeKeyword Keyword,
+                                 NestedNameSpecifierLoc QualifierLoc,
+                                 QualType Named) {
+    return SemaRef.Context.getElaboratedType(Keyword, 
+                                         QualifierLoc.getNestedNameSpecifier(), 
+                                             Named);
+  }
+
+  /// \brief Build a new typename type that refers to a template-id.
+  ///
+  /// By default, builds a new DependentNameType type from the
+  /// nested-name-specifier and the given type. Subclasses may override
+  /// this routine to provide different behavior.
+  QualType RebuildDependentTemplateSpecializationType(
+                                          ElaboratedTypeKeyword Keyword,
+                                          NestedNameSpecifierLoc QualifierLoc,
+                                          const IdentifierInfo *Name,
+                                          SourceLocation NameLoc,
+                                          TemplateArgumentListInfo &Args) {
+    // Rebuild the template name.
+    // TODO: avoid TemplateName abstraction
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+    TemplateName InstName 
+      = getDerived().RebuildTemplateName(SS, *Name, NameLoc, QualType(), 0);
+    
+    if (InstName.isNull())
+      return QualType();
+    
+    // If it's still dependent, make a dependent specialization.
+    if (InstName.getAsDependentTemplateName())
+      return SemaRef.Context.getDependentTemplateSpecializationType(Keyword, 
+                                          QualifierLoc.getNestedNameSpecifier(), 
+                                                                    Name, 
+                                                                    Args);
+    
+    // Otherwise, make an elaborated type wrapping a non-dependent
+    // specialization.
+    QualType T =
+    getDerived().RebuildTemplateSpecializationType(InstName, NameLoc, Args);
+    if (T.isNull()) return QualType();
+    
+    if (Keyword == ETK_None && QualifierLoc.getNestedNameSpecifier() == 0)
+      return T;
+    
+    return SemaRef.Context.getElaboratedType(Keyword, 
+                                       QualifierLoc.getNestedNameSpecifier(), 
+                                             T);
+  }
+
+  /// \brief Build a new typename type that refers to an identifier.
+  ///
+  /// By default, performs semantic analysis when building the typename type
+  /// (or elaborated type). Subclasses may override this routine to provide
+  /// different behavior.
+  QualType RebuildDependentNameType(ElaboratedTypeKeyword Keyword,
+                                    SourceLocation KeywordLoc,
+                                    NestedNameSpecifierLoc QualifierLoc,
+                                    const IdentifierInfo *Id,
+                                    SourceLocation IdLoc) {
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+
+    if (QualifierLoc.getNestedNameSpecifier()->isDependent()) {
+      // If the name is still dependent, just build a new dependent name type.
+      if (!SemaRef.computeDeclContext(SS))
+        return SemaRef.Context.getDependentNameType(Keyword, 
+                                          QualifierLoc.getNestedNameSpecifier(), 
+                                                    Id);
+    }
+
+    if (Keyword == ETK_None || Keyword == ETK_Typename)
+      return SemaRef.CheckTypenameType(Keyword, KeywordLoc, QualifierLoc,
+                                       *Id, IdLoc);
+
+    TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForKeyword(Keyword);
+
+    // We had a dependent elaborated-type-specifier that has been transformed
+    // into a non-dependent elaborated-type-specifier. Find the tag we're
+    // referring to.
+    LookupResult Result(SemaRef, Id, IdLoc, Sema::LookupTagName);
+    DeclContext *DC = SemaRef.computeDeclContext(SS, false);
+    if (!DC)
+      return QualType();
+
+    if (SemaRef.RequireCompleteDeclContext(SS, DC))
+      return QualType();
+
+    TagDecl *Tag = 0;
+    SemaRef.LookupQualifiedName(Result, DC);
+    switch (Result.getResultKind()) {
+      case LookupResult::NotFound:
+      case LookupResult::NotFoundInCurrentInstantiation:
+        break;
+        
+      case LookupResult::Found:
+        Tag = Result.getAsSingle<TagDecl>();
+        break;
+        
+      case LookupResult::FoundOverloaded:
+      case LookupResult::FoundUnresolvedValue:
+        llvm_unreachable("Tag lookup cannot find non-tags");
+        
+      case LookupResult::Ambiguous:
+        // Let the LookupResult structure handle ambiguities.
+        return QualType();
+    }
+
+    if (!Tag) {
+      // Check where the name exists but isn't a tag type and use that to emit
+      // better diagnostics.
+      LookupResult Result(SemaRef, Id, IdLoc, Sema::LookupTagName);
+      SemaRef.LookupQualifiedName(Result, DC);
+      switch (Result.getResultKind()) {
+        case LookupResult::Found:
+        case LookupResult::FoundOverloaded:
+        case LookupResult::FoundUnresolvedValue: {
+          NamedDecl *SomeDecl = Result.getRepresentativeDecl();
+          unsigned Kind = 0;
+          if (isa<TypedefDecl>(SomeDecl)) Kind = 1;
+          else if (isa<TypeAliasDecl>(SomeDecl)) Kind = 2;
+          else if (isa<ClassTemplateDecl>(SomeDecl)) Kind = 3;
+          SemaRef.Diag(IdLoc, diag::err_tag_reference_non_tag) << Kind;
+          SemaRef.Diag(SomeDecl->getLocation(), diag::note_declared_at);
+          break;
+        }
+        default:
+          // FIXME: Would be nice to highlight just the source range.
+          SemaRef.Diag(IdLoc, diag::err_not_tag_in_scope)
+            << Kind << Id << DC;
+          break;
+      }
+      return QualType();
+    }
+
+    if (!SemaRef.isAcceptableTagRedeclaration(Tag, Kind, /*isDefinition*/false,
+                                              IdLoc, *Id)) {
+      SemaRef.Diag(KeywordLoc, diag::err_use_with_wrong_tag) << Id;
+      SemaRef.Diag(Tag->getLocation(), diag::note_previous_use);
+      return QualType();
+    }
+
+    // Build the elaborated-type-specifier type.
+    QualType T = SemaRef.Context.getTypeDeclType(Tag);
+    return SemaRef.Context.getElaboratedType(Keyword, 
+                                         QualifierLoc.getNestedNameSpecifier(), 
+                                             T);
+  }
+
+  /// \brief Build a new pack expansion type.
+  ///
+  /// By default, builds a new PackExpansionType type from the given pattern.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildPackExpansionType(QualType Pattern, 
+                                    SourceRange PatternRange,
+                                    SourceLocation EllipsisLoc,
+                                    llvm::Optional<unsigned> NumExpansions) {
+    return getSema().CheckPackExpansion(Pattern, PatternRange, EllipsisLoc,
+                                        NumExpansions);
+  }
+
+  /// \brief Build a new atomic type given its value type.
+  ///
+  /// By default, performs semantic analysis when building the atomic type.
+  /// Subclasses may override this routine to provide different behavior.
+  QualType RebuildAtomicType(QualType ValueType, SourceLocation KWLoc);
+
+  /// \brief Build a new template name given a nested name specifier, a flag
+  /// indicating whether the "template" keyword was provided, and the template
+  /// that the template name refers to.
+  ///
+  /// By default, builds the new template name directly. Subclasses may override
+  /// this routine to provide different behavior.
+  TemplateName RebuildTemplateName(CXXScopeSpec &SS,
+                                   bool TemplateKW,
+                                   TemplateDecl *Template);
+
+  /// \brief Build a new template name given a nested name specifier and the
+  /// name that is referred to as a template.
+  ///
+  /// By default, performs semantic analysis to determine whether the name can
+  /// be resolved to a specific template, then builds the appropriate kind of
+  /// template name. Subclasses may override this routine to provide different
+  /// behavior.
+  TemplateName RebuildTemplateName(CXXScopeSpec &SS,
+                                   const IdentifierInfo &Name,
+                                   SourceLocation NameLoc,
+                                   QualType ObjectType,
+                                   NamedDecl *FirstQualifierInScope);
+
+  /// \brief Build a new template name given a nested name specifier and the
+  /// overloaded operator name that is referred to as a template.
+  ///
+  /// By default, performs semantic analysis to determine whether the name can
+  /// be resolved to a specific template, then builds the appropriate kind of
+  /// template name. Subclasses may override this routine to provide different
+  /// behavior.
+  TemplateName RebuildTemplateName(CXXScopeSpec &SS,
+                                   OverloadedOperatorKind Operator,
+                                   SourceLocation NameLoc,
+                                   QualType ObjectType);
+
+  /// \brief Build a new template name given a template template parameter pack
+  /// and the 
+  ///
+  /// By default, performs semantic analysis to determine whether the name can
+  /// be resolved to a specific template, then builds the appropriate kind of
+  /// template name. Subclasses may override this routine to provide different
+  /// behavior.
+  TemplateName RebuildTemplateName(TemplateTemplateParmDecl *Param,
+                                   const TemplateArgument &ArgPack) {
+    return getSema().Context.getSubstTemplateTemplateParmPack(Param, ArgPack);
+  }
+
+  /// \brief Build a new compound statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildCompoundStmt(SourceLocation LBraceLoc,
+                                       MultiStmtArg Statements,
+                                       SourceLocation RBraceLoc,
+                                       bool IsStmtExpr) {
+    return getSema().ActOnCompoundStmt(LBraceLoc, RBraceLoc, Statements,
+                                       IsStmtExpr);
+  }
+
+  /// \brief Build a new case statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildCaseStmt(SourceLocation CaseLoc,
+                                   Expr *LHS,
+                                   SourceLocation EllipsisLoc,
+                                   Expr *RHS,
+                                   SourceLocation ColonLoc) {
+    return getSema().ActOnCaseStmt(CaseLoc, LHS, EllipsisLoc, RHS,
+                                   ColonLoc);
+  }
+
+  /// \brief Attach the body to a new case statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildCaseStmtBody(Stmt *S, Stmt *Body) {
+    getSema().ActOnCaseStmtBody(S, Body);
+    return S;
+  }
+
+  /// \brief Build a new default statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildDefaultStmt(SourceLocation DefaultLoc,
+                                      SourceLocation ColonLoc,
+                                      Stmt *SubStmt) {
+    return getSema().ActOnDefaultStmt(DefaultLoc, ColonLoc, SubStmt,
+                                      /*CurScope=*/0);
+  }
+
+  /// \brief Build a new label statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildLabelStmt(SourceLocation IdentLoc, LabelDecl *L,
+                              SourceLocation ColonLoc, Stmt *SubStmt) {
+    return SemaRef.ActOnLabelStmt(IdentLoc, L, ColonLoc, SubStmt);
+  }
+
+  /// \brief Build a new label statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildAttributedStmt(SourceLocation AttrLoc, const AttrVec &Attrs,
+                                   Stmt *SubStmt) {
+    return SemaRef.ActOnAttributedStmt(AttrLoc, Attrs, SubStmt);
+  }
+
+  /// \brief Build a new "if" statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildIfStmt(SourceLocation IfLoc, Sema::FullExprArg Cond,
+                           VarDecl *CondVar, Stmt *Then, 
+                           SourceLocation ElseLoc, Stmt *Else) {
+    return getSema().ActOnIfStmt(IfLoc, Cond, CondVar, Then, ElseLoc, Else);
+  }
+
+  /// \brief Start building a new switch statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildSwitchStmtStart(SourceLocation SwitchLoc,
+                                    Expr *Cond, VarDecl *CondVar) {
+    return getSema().ActOnStartOfSwitchStmt(SwitchLoc, Cond, 
+                                            CondVar);
+  }
+
+  /// \brief Attach the body to the switch statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildSwitchStmtBody(SourceLocation SwitchLoc,
+                                   Stmt *Switch, Stmt *Body) {
+    return getSema().ActOnFinishSwitchStmt(SwitchLoc, Switch, Body);
+  }
+
+  /// \brief Build a new while statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildWhileStmt(SourceLocation WhileLoc, Sema::FullExprArg Cond,
+                              VarDecl *CondVar, Stmt *Body) {
+    return getSema().ActOnWhileStmt(WhileLoc, Cond, CondVar, Body);
+  }
+
+  /// \brief Build a new do-while statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildDoStmt(SourceLocation DoLoc, Stmt *Body,
+                           SourceLocation WhileLoc, SourceLocation LParenLoc,
+                           Expr *Cond, SourceLocation RParenLoc) {
+    return getSema().ActOnDoStmt(DoLoc, Body, WhileLoc, LParenLoc,
+                                 Cond, RParenLoc);
+  }
+
+  /// \brief Build a new for statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
+                            Stmt *Init, Sema::FullExprArg Cond, 
+                            VarDecl *CondVar, Sema::FullExprArg Inc,
+                            SourceLocation RParenLoc, Stmt *Body) {
+    return getSema().ActOnForStmt(ForLoc, LParenLoc, Init, Cond, 
+                                  CondVar, Inc, RParenLoc, Body);
+  }
+
+  /// \brief Build a new goto statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
+                             LabelDecl *Label) {
+    return getSema().ActOnGotoStmt(GotoLoc, LabelLoc, Label);
+  }
+
+  /// \brief Build a new indirect goto statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildIndirectGotoStmt(SourceLocation GotoLoc,
+                                     SourceLocation StarLoc,
+                                     Expr *Target) {
+    return getSema().ActOnIndirectGotoStmt(GotoLoc, StarLoc, Target);
+  }
+
+  /// \brief Build a new return statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildReturnStmt(SourceLocation ReturnLoc, Expr *Result) {
+    return getSema().ActOnReturnStmt(ReturnLoc, Result);
+  }
+
+  /// \brief Build a new declaration statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildDeclStmt(Decl **Decls, unsigned NumDecls,
+                                   SourceLocation StartLoc,
+                                   SourceLocation EndLoc) {
+    Sema::DeclGroupPtrTy DG = getSema().BuildDeclaratorGroup(Decls, NumDecls);
+    return getSema().ActOnDeclStmt(DG, StartLoc, EndLoc);
+  }
+
+  /// \brief Build a new inline asm statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildAsmStmt(SourceLocation AsmLoc,
+                                  bool IsSimple,
+                                  bool IsVolatile,
+                                  unsigned NumOutputs,
+                                  unsigned NumInputs,
+                                  IdentifierInfo **Names,
+                                  MultiExprArg Constraints,
+                                  MultiExprArg Exprs,
+                                  Expr *AsmString,
+                                  MultiExprArg Clobbers,
+                                  SourceLocation RParenLoc,
+                                  bool MSAsm) {
+    return getSema().ActOnAsmStmt(AsmLoc, IsSimple, IsVolatile, NumOutputs, 
+                                  NumInputs, Names, move(Constraints),
+                                  Exprs, AsmString, Clobbers,
+                                  RParenLoc, MSAsm);
+  }
+
+  /// \brief Build a new Objective-C @try statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildObjCAtTryStmt(SourceLocation AtLoc,
+                                        Stmt *TryBody,
+                                        MultiStmtArg CatchStmts,
+                                        Stmt *Finally) {
+    return getSema().ActOnObjCAtTryStmt(AtLoc, TryBody, move(CatchStmts),
+                                        Finally);
+  }
+
+  /// \brief Rebuild an Objective-C exception declaration.
+  ///
+  /// By default, performs semantic analysis to build the new declaration.
+  /// Subclasses may override this routine to provide different behavior.
+  VarDecl *RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
+                                    TypeSourceInfo *TInfo, QualType T) {
+    return getSema().BuildObjCExceptionDecl(TInfo, T,
+                                            ExceptionDecl->getInnerLocStart(),
+                                            ExceptionDecl->getLocation(),
+                                            ExceptionDecl->getIdentifier());
+  }
+  
+  /// \brief Build a new Objective-C @catch statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildObjCAtCatchStmt(SourceLocation AtLoc,
+                                          SourceLocation RParenLoc,
+                                          VarDecl *Var,
+                                          Stmt *Body) {
+    return getSema().ActOnObjCAtCatchStmt(AtLoc, RParenLoc,
+                                          Var, Body);
+  }
+  
+  /// \brief Build a new Objective-C @finally statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildObjCAtFinallyStmt(SourceLocation AtLoc,
+                                            Stmt *Body) {
+    return getSema().ActOnObjCAtFinallyStmt(AtLoc, Body);
+  }
+  
+  /// \brief Build a new Objective-C @throw statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildObjCAtThrowStmt(SourceLocation AtLoc,
+                                          Expr *Operand) {
+    return getSema().BuildObjCAtThrowStmt(AtLoc, Operand);
+  }
+  
+  /// \brief Rebuild the operand to an Objective-C @synchronized statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCAtSynchronizedOperand(SourceLocation atLoc,
+                                              Expr *object) {
+    return getSema().ActOnObjCAtSynchronizedOperand(atLoc, object);
+  }
+
+  /// \brief Build a new Objective-C @synchronized statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildObjCAtSynchronizedStmt(SourceLocation AtLoc,
+                                           Expr *Object, Stmt *Body) {
+    return getSema().ActOnObjCAtSynchronizedStmt(AtLoc, Object, Body);
+  }
+
+  /// \brief Build a new Objective-C @autoreleasepool statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildObjCAutoreleasePoolStmt(SourceLocation AtLoc,
+                                            Stmt *Body) {
+    return getSema().ActOnObjCAutoreleasePoolStmt(AtLoc, Body);
+  }
+
+  /// \brief Build the collection operand to a new Objective-C fast
+  /// enumeration statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCForCollectionOperand(SourceLocation forLoc,
+                                             Expr *collection) {
+    return getSema().ActOnObjCForCollectionOperand(forLoc, collection);
+  }
+
+  /// \brief Build a new Objective-C fast enumeration statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildObjCForCollectionStmt(SourceLocation ForLoc,
+                                          SourceLocation LParenLoc,
+                                          Stmt *Element,
+                                          Expr *Collection,
+                                          SourceLocation RParenLoc,
+                                          Stmt *Body) {
+    return getSema().ActOnObjCForCollectionStmt(ForLoc, LParenLoc,
+                                                Element, 
+                                                Collection,
+                                                RParenLoc,
+                                                Body);
+  }
+  
+  /// \brief Build a new C++ exception declaration.
+  ///
+  /// By default, performs semantic analysis to build the new decaration.
+  /// Subclasses may override this routine to provide different behavior.
+  VarDecl *RebuildExceptionDecl(VarDecl *ExceptionDecl,
+                                TypeSourceInfo *Declarator,
+                                SourceLocation StartLoc,
+                                SourceLocation IdLoc,
+                                IdentifierInfo *Id) {
+    VarDecl *Var = getSema().BuildExceptionDeclaration(0, Declarator,
+                                                       StartLoc, IdLoc, Id);
+    if (Var)
+      getSema().CurContext->addDecl(Var);
+    return Var;
+  }
+
+  /// \brief Build a new C++ catch statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildCXXCatchStmt(SourceLocation CatchLoc,
+                                 VarDecl *ExceptionDecl,
+                                 Stmt *Handler) {
+    return Owned(new (getSema().Context) CXXCatchStmt(CatchLoc, ExceptionDecl,
+                                                      Handler));
+  }
+
+  /// \brief Build a new C++ try statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildCXXTryStmt(SourceLocation TryLoc,
+                               Stmt *TryBlock,
+                               MultiStmtArg Handlers) {
+    return getSema().ActOnCXXTryBlock(TryLoc, TryBlock, move(Handlers));
+  }
+
+  /// \brief Build a new C++0x range-based for statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildCXXForRangeStmt(SourceLocation ForLoc,
+                                    SourceLocation ColonLoc,
+                                    Stmt *Range, Stmt *BeginEnd,
+                                    Expr *Cond, Expr *Inc,
+                                    Stmt *LoopVar,
+                                    SourceLocation RParenLoc) {
+    return getSema().BuildCXXForRangeStmt(ForLoc, ColonLoc, Range, BeginEnd,
+                                          Cond, Inc, LoopVar, RParenLoc);
+  }
+
+  /// \brief Build a new C++0x range-based for statement.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult RebuildMSDependentExistsStmt(SourceLocation KeywordLoc, 
+                                          bool IsIfExists,
+                                          NestedNameSpecifierLoc QualifierLoc,
+                                          DeclarationNameInfo NameInfo,
+                                          Stmt *Nested) {
+    return getSema().BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
+                                                QualifierLoc, NameInfo, Nested);
+  }
+
+  /// \brief Attach body to a C++0x range-based for statement.
+  ///
+  /// By default, performs semantic analysis to finish the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  StmtResult FinishCXXForRangeStmt(Stmt *ForRange, Stmt *Body) {
+    return getSema().FinishCXXForRangeStmt(ForRange, Body);
+  }
+  
+  StmtResult RebuildSEHTryStmt(bool IsCXXTry,
+                               SourceLocation TryLoc,
+                               Stmt *TryBlock,
+                               Stmt *Handler) {
+    return getSema().ActOnSEHTryBlock(IsCXXTry,TryLoc,TryBlock,Handler);
+  }
+
+  StmtResult RebuildSEHExceptStmt(SourceLocation Loc,
+                                  Expr *FilterExpr,
+                                  Stmt *Block) {
+    return getSema().ActOnSEHExceptBlock(Loc,FilterExpr,Block);
+  }
+
+  StmtResult RebuildSEHFinallyStmt(SourceLocation Loc,
+                                   Stmt *Block) {
+    return getSema().ActOnSEHFinallyBlock(Loc,Block);
+  }
+
+  /// \brief Build a new expression that references a declaration.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildDeclarationNameExpr(const CXXScopeSpec &SS,
+                                        LookupResult &R,
+                                        bool RequiresADL) {
+    return getSema().BuildDeclarationNameExpr(SS, R, RequiresADL);
+  }
+
+
+  /// \brief Build a new expression that references a declaration.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildDeclRefExpr(NestedNameSpecifierLoc QualifierLoc,
+                                ValueDecl *VD,
+                                const DeclarationNameInfo &NameInfo,
+                                TemplateArgumentListInfo *TemplateArgs) {
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+
+    // FIXME: loses template args.
+
+    return getSema().BuildDeclarationNameExpr(SS, NameInfo, VD);
+  }
+
+  /// \brief Build a new expression in parentheses.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildParenExpr(Expr *SubExpr, SourceLocation LParen,
+                                    SourceLocation RParen) {
+    return getSema().ActOnParenExpr(LParen, RParen, SubExpr);
+  }
+
+  /// \brief Build a new pseudo-destructor expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXPseudoDestructorExpr(Expr *Base,
+                                            SourceLocation OperatorLoc,
+                                            bool isArrow,
+                                            CXXScopeSpec &SS,
+                                            TypeSourceInfo *ScopeType,
+                                            SourceLocation CCLoc,
+                                            SourceLocation TildeLoc,
+                                        PseudoDestructorTypeStorage Destroyed);
+
+  /// \brief Build a new unary operator expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildUnaryOperator(SourceLocation OpLoc,
+                                        UnaryOperatorKind Opc,
+                                        Expr *SubExpr) {
+    return getSema().BuildUnaryOp(/*Scope=*/0, OpLoc, Opc, SubExpr);
+  }
+
+  /// \brief Build a new builtin offsetof expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildOffsetOfExpr(SourceLocation OperatorLoc,
+                                       TypeSourceInfo *Type,
+                                       Sema::OffsetOfComponent *Components,
+                                       unsigned NumComponents,
+                                       SourceLocation RParenLoc) {
+    return getSema().BuildBuiltinOffsetOf(OperatorLoc, Type, Components,
+                                          NumComponents, RParenLoc);
+  }
+  
+  /// \brief Build a new sizeof, alignof or vec_step expression with a 
+  /// type argument.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildUnaryExprOrTypeTrait(TypeSourceInfo *TInfo,
+                                         SourceLocation OpLoc,
+                                         UnaryExprOrTypeTrait ExprKind,
+                                         SourceRange R) {
+    return getSema().CreateUnaryExprOrTypeTraitExpr(TInfo, OpLoc, ExprKind, R);
+  }
+
+  /// \brief Build a new sizeof, alignof or vec step expression with an
+  /// expression argument.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildUnaryExprOrTypeTrait(Expr *SubExpr, SourceLocation OpLoc,
+                                         UnaryExprOrTypeTrait ExprKind,
+                                         SourceRange R) {
+    ExprResult Result
+      = getSema().CreateUnaryExprOrTypeTraitExpr(SubExpr, OpLoc, ExprKind);
+    if (Result.isInvalid())
+      return ExprError();
+
+    return move(Result);
+  }
+
+  /// \brief Build a new array subscript expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildArraySubscriptExpr(Expr *LHS,
+                                             SourceLocation LBracketLoc,
+                                             Expr *RHS,
+                                             SourceLocation RBracketLoc) {
+    return getSema().ActOnArraySubscriptExpr(/*Scope=*/0, LHS,
+                                             LBracketLoc, RHS,
+                                             RBracketLoc);
+  }
+
+  /// \brief Build a new call expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCallExpr(Expr *Callee, SourceLocation LParenLoc,
+                                   MultiExprArg Args,
+                                   SourceLocation RParenLoc,
+                                   Expr *ExecConfig = 0) {
+    return getSema().ActOnCallExpr(/*Scope=*/0, Callee, LParenLoc,
+                                   move(Args), RParenLoc, ExecConfig);
+  }
+
+  /// \brief Build a new member access expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildMemberExpr(Expr *Base, SourceLocation OpLoc,
+                               bool isArrow,
+                               NestedNameSpecifierLoc QualifierLoc,
+                               SourceLocation TemplateKWLoc,
+                               const DeclarationNameInfo &MemberNameInfo,
+                               ValueDecl *Member,
+                               NamedDecl *FoundDecl,
+                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                               NamedDecl *FirstQualifierInScope) {
+    ExprResult BaseResult = getSema().PerformMemberExprBaseConversion(Base,
+                                                                      isArrow);
+    if (!Member->getDeclName()) {
+      // We have a reference to an unnamed field.  This is always the
+      // base of an anonymous struct/union member access, i.e. the
+      // field is always of record type.
+      assert(!QualifierLoc && "Can't have an unnamed field with a qualifier!");
+      assert(Member->getType()->isRecordType() &&
+             "unnamed member not of record type?");
+
+      BaseResult =
+        getSema().PerformObjectMemberConversion(BaseResult.take(),
+                                                QualifierLoc.getNestedNameSpecifier(),
+                                                FoundDecl, Member);
+      if (BaseResult.isInvalid())
+        return ExprError();
+      Base = BaseResult.take();
+      ExprValueKind VK = isArrow ? VK_LValue : Base->getValueKind();
+      MemberExpr *ME =
+        new (getSema().Context) MemberExpr(Base, isArrow,
+                                           Member, MemberNameInfo,
+                                           cast<FieldDecl>(Member)->getType(),
+                                           VK, OK_Ordinary);
+      return getSema().Owned(ME);
+    }
+
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+
+    Base = BaseResult.take();
+    QualType BaseType = Base->getType();
+
+    // FIXME: this involves duplicating earlier analysis in a lot of
+    // cases; we should avoid this when possible.
+    LookupResult R(getSema(), MemberNameInfo, Sema::LookupMemberName);
+    R.addDecl(FoundDecl);
+    R.resolveKind();
+
+    return getSema().BuildMemberReferenceExpr(Base, BaseType, OpLoc, isArrow,
+                                              SS, TemplateKWLoc,
+                                              FirstQualifierInScope,
+                                              R, ExplicitTemplateArgs);
+  }
+
+  /// \brief Build a new binary operator expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildBinaryOperator(SourceLocation OpLoc,
+                                         BinaryOperatorKind Opc,
+                                         Expr *LHS, Expr *RHS) {
+    return getSema().BuildBinOp(/*Scope=*/0, OpLoc, Opc, LHS, RHS);
+  }
+
+  /// \brief Build a new conditional operator expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildConditionalOperator(Expr *Cond,
+                                        SourceLocation QuestionLoc,
+                                        Expr *LHS,
+                                        SourceLocation ColonLoc,
+                                        Expr *RHS) {
+    return getSema().ActOnConditionalOp(QuestionLoc, ColonLoc, Cond,
+                                        LHS, RHS);
+  }
+
+  /// \brief Build a new C-style cast expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCStyleCastExpr(SourceLocation LParenLoc,
+                                         TypeSourceInfo *TInfo,
+                                         SourceLocation RParenLoc,
+                                         Expr *SubExpr) {
+    return getSema().BuildCStyleCastExpr(LParenLoc, TInfo, RParenLoc,
+                                         SubExpr);
+  }
+
+  /// \brief Build a new compound literal expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCompoundLiteralExpr(SourceLocation LParenLoc,
+                                              TypeSourceInfo *TInfo,
+                                              SourceLocation RParenLoc,
+                                              Expr *Init) {
+    return getSema().BuildCompoundLiteralExpr(LParenLoc, TInfo, RParenLoc,
+                                              Init);
+  }
+
+  /// \brief Build a new extended vector element access expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildExtVectorElementExpr(Expr *Base,
+                                               SourceLocation OpLoc,
+                                               SourceLocation AccessorLoc,
+                                               IdentifierInfo &Accessor) {
+
+    CXXScopeSpec SS;
+    DeclarationNameInfo NameInfo(&Accessor, AccessorLoc);
+    return getSema().BuildMemberReferenceExpr(Base, Base->getType(),
+                                              OpLoc, /*IsArrow*/ false,
+                                              SS, SourceLocation(),
+                                              /*FirstQualifierInScope*/ 0,
+                                              NameInfo,
+                                              /* TemplateArgs */ 0);
+  }
+
+  /// \brief Build a new initializer list expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildInitList(SourceLocation LBraceLoc,
+                             MultiExprArg Inits,
+                             SourceLocation RBraceLoc,
+                             QualType ResultTy) {
+    ExprResult Result
+      = SemaRef.ActOnInitList(LBraceLoc, move(Inits), RBraceLoc);
+    if (Result.isInvalid() || ResultTy->isDependentType())
+      return move(Result);
+    
+    // Patch in the result type we were given, which may have been computed
+    // when the initial InitListExpr was built.
+    InitListExpr *ILE = cast<InitListExpr>((Expr *)Result.get());
+    ILE->setType(ResultTy);
+    return move(Result);
+  }
+
+  /// \brief Build a new designated initializer expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildDesignatedInitExpr(Designation &Desig,
+                                             MultiExprArg ArrayExprs,
+                                             SourceLocation EqualOrColonLoc,
+                                             bool GNUSyntax,
+                                             Expr *Init) {
+    ExprResult Result
+      = SemaRef.ActOnDesignatedInitializer(Desig, EqualOrColonLoc, GNUSyntax,
+                                           Init);
+    if (Result.isInvalid())
+      return ExprError();
+
+    ArrayExprs.release();
+    return move(Result);
+  }
+
+  /// \brief Build a new value-initialized expression.
+  ///
+  /// By default, builds the implicit value initialization without performing
+  /// any semantic analysis. Subclasses may override this routine to provide
+  /// different behavior.
+  ExprResult RebuildImplicitValueInitExpr(QualType T) {
+    return SemaRef.Owned(new (SemaRef.Context) ImplicitValueInitExpr(T));
+  }
+
+  /// \brief Build a new \c va_arg expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildVAArgExpr(SourceLocation BuiltinLoc,
+                                    Expr *SubExpr, TypeSourceInfo *TInfo,
+                                    SourceLocation RParenLoc) {
+    return getSema().BuildVAArgExpr(BuiltinLoc,
+                                    SubExpr, TInfo,
+                                    RParenLoc);
+  }
+
+  /// \brief Build a new expression list in parentheses.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildParenListExpr(SourceLocation LParenLoc,
+                                  MultiExprArg SubExprs,
+                                  SourceLocation RParenLoc) {
+    return getSema().ActOnParenListExpr(LParenLoc, RParenLoc, move(SubExprs));
+  }
+
+  /// \brief Build a new address-of-label expression.
+  ///
+  /// By default, performs semantic analysis, using the name of the label
+  /// rather than attempting to map the label statement itself.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildAddrLabelExpr(SourceLocation AmpAmpLoc,
+                                  SourceLocation LabelLoc, LabelDecl *Label) {
+    return getSema().ActOnAddrLabel(AmpAmpLoc, LabelLoc, Label);
+  }
+
+  /// \brief Build a new GNU statement expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildStmtExpr(SourceLocation LParenLoc,
+                                   Stmt *SubStmt,
+                                   SourceLocation RParenLoc) {
+    return getSema().ActOnStmtExpr(LParenLoc, SubStmt, RParenLoc);
+  }
+
+  /// \brief Build a new __builtin_choose_expr expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildChooseExpr(SourceLocation BuiltinLoc,
+                                     Expr *Cond, Expr *LHS, Expr *RHS,
+                                     SourceLocation RParenLoc) {
+    return SemaRef.ActOnChooseExpr(BuiltinLoc,
+                                   Cond, LHS, RHS,
+                                   RParenLoc);
+  }
+
+  /// \brief Build a new generic selection expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildGenericSelectionExpr(SourceLocation KeyLoc,
+                                         SourceLocation DefaultLoc,
+                                         SourceLocation RParenLoc,
+                                         Expr *ControllingExpr,
+                                         TypeSourceInfo **Types,
+                                         Expr **Exprs,
+                                         unsigned NumAssocs) {
+    return getSema().CreateGenericSelectionExpr(KeyLoc, DefaultLoc, RParenLoc,
+                                                ControllingExpr, Types, Exprs,
+                                                NumAssocs);
+  }
+
+  /// \brief Build a new overloaded operator call expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// The semantic analysis provides the behavior of template instantiation,
+  /// copying with transformations that turn what looks like an overloaded
+  /// operator call into a use of a builtin operator, performing
+  /// argument-dependent lookup, etc. Subclasses may override this routine to
+  /// provide different behavior.
+  ExprResult RebuildCXXOperatorCallExpr(OverloadedOperatorKind Op,
+                                              SourceLocation OpLoc,
+                                              Expr *Callee,
+                                              Expr *First,
+                                              Expr *Second);
+
+  /// \brief Build a new C++ "named" cast expression, such as static_cast or
+  /// reinterpret_cast.
+  ///
+  /// By default, this routine dispatches to one of the more-specific routines
+  /// for a particular named case, e.g., RebuildCXXStaticCastExpr().
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXNamedCastExpr(SourceLocation OpLoc,
+                                           Stmt::StmtClass Class,
+                                           SourceLocation LAngleLoc,
+                                           TypeSourceInfo *TInfo,
+                                           SourceLocation RAngleLoc,
+                                           SourceLocation LParenLoc,
+                                           Expr *SubExpr,
+                                           SourceLocation RParenLoc) {
+    switch (Class) {
+    case Stmt::CXXStaticCastExprClass:
+      return getDerived().RebuildCXXStaticCastExpr(OpLoc, LAngleLoc, TInfo,
+                                                   RAngleLoc, LParenLoc,
+                                                   SubExpr, RParenLoc);
+
+    case Stmt::CXXDynamicCastExprClass:
+      return getDerived().RebuildCXXDynamicCastExpr(OpLoc, LAngleLoc, TInfo,
+                                                    RAngleLoc, LParenLoc,
+                                                    SubExpr, RParenLoc);
+
+    case Stmt::CXXReinterpretCastExprClass:
+      return getDerived().RebuildCXXReinterpretCastExpr(OpLoc, LAngleLoc, TInfo,
+                                                        RAngleLoc, LParenLoc,
+                                                        SubExpr,
+                                                        RParenLoc);
+
+    case Stmt::CXXConstCastExprClass:
+      return getDerived().RebuildCXXConstCastExpr(OpLoc, LAngleLoc, TInfo,
+                                                   RAngleLoc, LParenLoc,
+                                                   SubExpr, RParenLoc);
+
+    default:
+      llvm_unreachable("Invalid C++ named cast");
+    }
+  }
+
+  /// \brief Build a new C++ static_cast expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXStaticCastExpr(SourceLocation OpLoc,
+                                            SourceLocation LAngleLoc,
+                                            TypeSourceInfo *TInfo,
+                                            SourceLocation RAngleLoc,
+                                            SourceLocation LParenLoc,
+                                            Expr *SubExpr,
+                                            SourceLocation RParenLoc) {
+    return getSema().BuildCXXNamedCast(OpLoc, tok::kw_static_cast,
+                                       TInfo, SubExpr,
+                                       SourceRange(LAngleLoc, RAngleLoc),
+                                       SourceRange(LParenLoc, RParenLoc));
+  }
+
+  /// \brief Build a new C++ dynamic_cast expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXDynamicCastExpr(SourceLocation OpLoc,
+                                             SourceLocation LAngleLoc,
+                                             TypeSourceInfo *TInfo,
+                                             SourceLocation RAngleLoc,
+                                             SourceLocation LParenLoc,
+                                             Expr *SubExpr,
+                                             SourceLocation RParenLoc) {
+    return getSema().BuildCXXNamedCast(OpLoc, tok::kw_dynamic_cast,
+                                       TInfo, SubExpr,
+                                       SourceRange(LAngleLoc, RAngleLoc),
+                                       SourceRange(LParenLoc, RParenLoc));
+  }
+
+  /// \brief Build a new C++ reinterpret_cast expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXReinterpretCastExpr(SourceLocation OpLoc,
+                                                 SourceLocation LAngleLoc,
+                                                 TypeSourceInfo *TInfo,
+                                                 SourceLocation RAngleLoc,
+                                                 SourceLocation LParenLoc,
+                                                 Expr *SubExpr,
+                                                 SourceLocation RParenLoc) {
+    return getSema().BuildCXXNamedCast(OpLoc, tok::kw_reinterpret_cast,
+                                       TInfo, SubExpr,
+                                       SourceRange(LAngleLoc, RAngleLoc),
+                                       SourceRange(LParenLoc, RParenLoc));
+  }
+
+  /// \brief Build a new C++ const_cast expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXConstCastExpr(SourceLocation OpLoc,
+                                           SourceLocation LAngleLoc,
+                                           TypeSourceInfo *TInfo,
+                                           SourceLocation RAngleLoc,
+                                           SourceLocation LParenLoc,
+                                           Expr *SubExpr,
+                                           SourceLocation RParenLoc) {
+    return getSema().BuildCXXNamedCast(OpLoc, tok::kw_const_cast,
+                                       TInfo, SubExpr,
+                                       SourceRange(LAngleLoc, RAngleLoc),
+                                       SourceRange(LParenLoc, RParenLoc));
+  }
+
+  /// \brief Build a new C++ functional-style cast expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXFunctionalCastExpr(TypeSourceInfo *TInfo,
+                                          SourceLocation LParenLoc,
+                                          Expr *Sub,
+                                          SourceLocation RParenLoc) {
+    return getSema().BuildCXXTypeConstructExpr(TInfo, LParenLoc,
+                                               MultiExprArg(&Sub, 1),
+                                               RParenLoc);
+  }
+
+  /// \brief Build a new C++ typeid(type) expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXTypeidExpr(QualType TypeInfoType,
+                                        SourceLocation TypeidLoc,
+                                        TypeSourceInfo *Operand,
+                                        SourceLocation RParenLoc) {
+    return getSema().BuildCXXTypeId(TypeInfoType, TypeidLoc, Operand, 
+                                    RParenLoc);
+  }
+
+
+  /// \brief Build a new C++ typeid(expr) expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXTypeidExpr(QualType TypeInfoType,
+                                        SourceLocation TypeidLoc,
+                                        Expr *Operand,
+                                        SourceLocation RParenLoc) {
+    return getSema().BuildCXXTypeId(TypeInfoType, TypeidLoc, Operand,
+                                    RParenLoc);
+  }
+
+  /// \brief Build a new C++ __uuidof(type) expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXUuidofExpr(QualType TypeInfoType,
+                                        SourceLocation TypeidLoc,
+                                        TypeSourceInfo *Operand,
+                                        SourceLocation RParenLoc) {
+    return getSema().BuildCXXUuidof(TypeInfoType, TypeidLoc, Operand, 
+                                    RParenLoc);
+  }
+
+  /// \brief Build a new C++ __uuidof(expr) expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXUuidofExpr(QualType TypeInfoType,
+                                        SourceLocation TypeidLoc,
+                                        Expr *Operand,
+                                        SourceLocation RParenLoc) {
+    return getSema().BuildCXXUuidof(TypeInfoType, TypeidLoc, Operand,
+                                    RParenLoc);
+  }
+
+  /// \brief Build a new C++ "this" expression.
+  ///
+  /// By default, builds a new "this" expression without performing any
+  /// semantic analysis. Subclasses may override this routine to provide
+  /// different behavior.
+  ExprResult RebuildCXXThisExpr(SourceLocation ThisLoc,
+                                QualType ThisType,
+                                bool isImplicit) {
+    getSema().CheckCXXThisCapture(ThisLoc);
+    return getSema().Owned(
+                      new (getSema().Context) CXXThisExpr(ThisLoc, ThisType,
+                                                          isImplicit));
+  }
+
+  /// \brief Build a new C++ throw expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXThrowExpr(SourceLocation ThrowLoc, Expr *Sub,
+                                 bool IsThrownVariableInScope) {
+    return getSema().BuildCXXThrow(ThrowLoc, Sub, IsThrownVariableInScope);
+  }
+
+  /// \brief Build a new C++ default-argument expression.
+  ///
+  /// By default, builds a new default-argument expression, which does not
+  /// require any semantic analysis. Subclasses may override this routine to
+  /// provide different behavior.
+  ExprResult RebuildCXXDefaultArgExpr(SourceLocation Loc, 
+                                            ParmVarDecl *Param) {
+    return getSema().Owned(CXXDefaultArgExpr::Create(getSema().Context, Loc,
+                                                     Param));
+  }
+
+  /// \brief Build a new C++ zero-initialization expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXScalarValueInitExpr(TypeSourceInfo *TSInfo,
+                                           SourceLocation LParenLoc,
+                                           SourceLocation RParenLoc) {
+    return getSema().BuildCXXTypeConstructExpr(TSInfo, LParenLoc,
+                                               MultiExprArg(getSema(), 0, 0),
+                                               RParenLoc);
+  }
+
+  /// \brief Build a new C++ "new" expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXNewExpr(SourceLocation StartLoc,
+                               bool UseGlobal,
+                               SourceLocation PlacementLParen,
+                               MultiExprArg PlacementArgs,
+                               SourceLocation PlacementRParen,
+                               SourceRange TypeIdParens,
+                               QualType AllocatedType,
+                               TypeSourceInfo *AllocatedTypeInfo,
+                               Expr *ArraySize,
+                               SourceRange DirectInitRange,
+                               Expr *Initializer) {
+    return getSema().BuildCXXNew(StartLoc, UseGlobal,
+                                 PlacementLParen,
+                                 move(PlacementArgs),
+                                 PlacementRParen,
+                                 TypeIdParens,
+                                 AllocatedType,
+                                 AllocatedTypeInfo,
+                                 ArraySize,
+                                 DirectInitRange,
+                                 Initializer);
+  }
+
+  /// \brief Build a new C++ "delete" expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXDeleteExpr(SourceLocation StartLoc,
+                                        bool IsGlobalDelete,
+                                        bool IsArrayForm,
+                                        Expr *Operand) {
+    return getSema().ActOnCXXDelete(StartLoc, IsGlobalDelete, IsArrayForm,
+                                    Operand);
+  }
+
+  /// \brief Build a new unary type trait expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildUnaryTypeTrait(UnaryTypeTrait Trait,
+                                   SourceLocation StartLoc,
+                                   TypeSourceInfo *T,
+                                   SourceLocation RParenLoc) {
+    return getSema().BuildUnaryTypeTrait(Trait, StartLoc, T, RParenLoc);
+  }
+
+  /// \brief Build a new binary type trait expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildBinaryTypeTrait(BinaryTypeTrait Trait,
+                                    SourceLocation StartLoc,
+                                    TypeSourceInfo *LhsT,
+                                    TypeSourceInfo *RhsT,
+                                    SourceLocation RParenLoc) {
+    return getSema().BuildBinaryTypeTrait(Trait, StartLoc, LhsT, RhsT, RParenLoc);
+  }
+
+  /// \brief Build a new type trait expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildTypeTrait(TypeTrait Trait,
+                              SourceLocation StartLoc,
+                              ArrayRef<TypeSourceInfo *> Args,
+                              SourceLocation RParenLoc) {
+    return getSema().BuildTypeTrait(Trait, StartLoc, Args, RParenLoc);
+  }
+  
+  /// \brief Build a new array type trait expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildArrayTypeTrait(ArrayTypeTrait Trait,
+                                   SourceLocation StartLoc,
+                                   TypeSourceInfo *TSInfo,
+                                   Expr *DimExpr,
+                                   SourceLocation RParenLoc) {
+    return getSema().BuildArrayTypeTrait(Trait, StartLoc, TSInfo, DimExpr, RParenLoc);
+  }
+
+  /// \brief Build a new expression trait expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildExpressionTrait(ExpressionTrait Trait,
+                                   SourceLocation StartLoc,
+                                   Expr *Queried,
+                                   SourceLocation RParenLoc) {
+    return getSema().BuildExpressionTrait(Trait, StartLoc, Queried, RParenLoc);
+  }
+
+  /// \brief Build a new (previously unresolved) declaration reference
+  /// expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildDependentScopeDeclRefExpr(
+                                          NestedNameSpecifierLoc QualifierLoc,
+                                          SourceLocation TemplateKWLoc,
+                                       const DeclarationNameInfo &NameInfo,
+                              const TemplateArgumentListInfo *TemplateArgs) {
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+
+    if (TemplateArgs || TemplateKWLoc.isValid())
+      return getSema().BuildQualifiedTemplateIdExpr(SS, TemplateKWLoc,
+                                                    NameInfo, TemplateArgs);
+
+    return getSema().BuildQualifiedDeclarationNameExpr(SS, NameInfo);
+  }
+
+  /// \brief Build a new template-id expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildTemplateIdExpr(const CXXScopeSpec &SS,
+                                   SourceLocation TemplateKWLoc,
+                                   LookupResult &R,
+                                   bool RequiresADL,
+                              const TemplateArgumentListInfo *TemplateArgs) {
+    return getSema().BuildTemplateIdExpr(SS, TemplateKWLoc, R, RequiresADL,
+                                         TemplateArgs);
+  }
+
+  /// \brief Build a new object-construction expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXConstructExpr(QualType T,
+                                     SourceLocation Loc,
+                                     CXXConstructorDecl *Constructor,
+                                     bool IsElidable,
+                                     MultiExprArg Args,
+                                     bool HadMultipleCandidates,
+                                     bool RequiresZeroInit,
+                             CXXConstructExpr::ConstructionKind ConstructKind,
+                                     SourceRange ParenRange) {
+    ASTOwningVector<Expr*> ConvertedArgs(SemaRef);
+    if (getSema().CompleteConstructorCall(Constructor, move(Args), Loc, 
+                                          ConvertedArgs))
+      return ExprError();
+    
+    return getSema().BuildCXXConstructExpr(Loc, T, Constructor, IsElidable,
+                                           move_arg(ConvertedArgs),
+                                           HadMultipleCandidates,
+                                           RequiresZeroInit, ConstructKind,
+                                           ParenRange);
+  }
+
+  /// \brief Build a new object-construction expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXTemporaryObjectExpr(TypeSourceInfo *TSInfo,
+                                           SourceLocation LParenLoc,
+                                           MultiExprArg Args,
+                                           SourceLocation RParenLoc) {
+    return getSema().BuildCXXTypeConstructExpr(TSInfo,
+                                               LParenLoc,
+                                               move(Args),
+                                               RParenLoc);
+  }
+
+  /// \brief Build a new object-construction expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXUnresolvedConstructExpr(TypeSourceInfo *TSInfo,
+                                               SourceLocation LParenLoc,
+                                               MultiExprArg Args,
+                                               SourceLocation RParenLoc) {
+    return getSema().BuildCXXTypeConstructExpr(TSInfo,
+                                               LParenLoc,
+                                               move(Args),
+                                               RParenLoc);
+  }
+
+  /// \brief Build a new member reference expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXDependentScopeMemberExpr(Expr *BaseE,
+                                                QualType BaseType,
+                                                bool IsArrow,
+                                                SourceLocation OperatorLoc,
+                                          NestedNameSpecifierLoc QualifierLoc,
+                                                SourceLocation TemplateKWLoc,
+                                            NamedDecl *FirstQualifierInScope,
+                                   const DeclarationNameInfo &MemberNameInfo,
+                              const TemplateArgumentListInfo *TemplateArgs) {
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+
+    return SemaRef.BuildMemberReferenceExpr(BaseE, BaseType,
+                                            OperatorLoc, IsArrow,
+                                            SS, TemplateKWLoc,
+                                            FirstQualifierInScope,
+                                            MemberNameInfo,
+                                            TemplateArgs);
+  }
+
+  /// \brief Build a new member reference expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildUnresolvedMemberExpr(Expr *BaseE, QualType BaseType,
+                                         SourceLocation OperatorLoc,
+                                         bool IsArrow,
+                                         NestedNameSpecifierLoc QualifierLoc,
+                                         SourceLocation TemplateKWLoc,
+                                         NamedDecl *FirstQualifierInScope,
+                                         LookupResult &R,
+                                const TemplateArgumentListInfo *TemplateArgs) {
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+
+    return SemaRef.BuildMemberReferenceExpr(BaseE, BaseType,
+                                            OperatorLoc, IsArrow,
+                                            SS, TemplateKWLoc,
+                                            FirstQualifierInScope,
+                                            R, TemplateArgs);
+  }
+
+  /// \brief Build a new noexcept expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXNoexceptExpr(SourceRange Range, Expr *Arg) {
+    return SemaRef.BuildCXXNoexceptExpr(Range.getBegin(), Arg, Range.getEnd());
+  }
+
+  /// \brief Build a new expression to compute the length of a parameter pack.
+  ExprResult RebuildSizeOfPackExpr(SourceLocation OperatorLoc, NamedDecl *Pack, 
+                                   SourceLocation PackLoc, 
+                                   SourceLocation RParenLoc,
+                                   llvm::Optional<unsigned> Length) {
+    if (Length)
+      return new (SemaRef.Context) SizeOfPackExpr(SemaRef.Context.getSizeType(), 
+                                                  OperatorLoc, Pack, PackLoc, 
+                                                  RParenLoc, *Length);
+    
+    return new (SemaRef.Context) SizeOfPackExpr(SemaRef.Context.getSizeType(), 
+                                                OperatorLoc, Pack, PackLoc, 
+                                                RParenLoc);
+  }
+
+  /// \brief Build a new Objective-C array literal.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCArrayLiteral(SourceRange Range,
+                                     Expr **Elements, unsigned NumElements) {
+    return getSema().BuildObjCArrayLiteral(Range, 
+                                           MultiExprArg(Elements, NumElements));
+  }
+ 
+  ExprResult RebuildObjCSubscriptRefExpr(SourceLocation RB, 
+                                         Expr *Base, Expr *Key,
+                                         ObjCMethodDecl *getterMethod,
+                                         ObjCMethodDecl *setterMethod) {
+    return  getSema().BuildObjCSubscriptExpression(RB, Base, Key,
+                                                   getterMethod, setterMethod);
+  }
+
+  /// \brief Build a new Objective-C dictionary literal.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCDictionaryLiteral(SourceRange Range,
+                                          ObjCDictionaryElement *Elements,
+                                          unsigned NumElements) {
+    return getSema().BuildObjCDictionaryLiteral(Range, Elements, NumElements);
+  }
+  
+  /// \brief Build a new Objective-C @encode expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCEncodeExpr(SourceLocation AtLoc,
+                                         TypeSourceInfo *EncodeTypeInfo,
+                                         SourceLocation RParenLoc) {
+    return SemaRef.Owned(SemaRef.BuildObjCEncodeExpression(AtLoc, EncodeTypeInfo,
+                                                           RParenLoc));
+  }
+
+  /// \brief Build a new Objective-C class message.
+  ExprResult RebuildObjCMessageExpr(TypeSourceInfo *ReceiverTypeInfo,
+                                          Selector Sel,
+                                          ArrayRef<SourceLocation> SelectorLocs,
+                                          ObjCMethodDecl *Method,
+                                          SourceLocation LBracLoc, 
+                                          MultiExprArg Args,
+                                          SourceLocation RBracLoc) {
+    return SemaRef.BuildClassMessage(ReceiverTypeInfo,
+                                     ReceiverTypeInfo->getType(),
+                                     /*SuperLoc=*/SourceLocation(),
+                                     Sel, Method, LBracLoc, SelectorLocs,
+                                     RBracLoc, move(Args));
+  }
+
+  /// \brief Build a new Objective-C instance message.
+  ExprResult RebuildObjCMessageExpr(Expr *Receiver,
+                                          Selector Sel,
+                                          ArrayRef<SourceLocation> SelectorLocs,
+                                          ObjCMethodDecl *Method,
+                                          SourceLocation LBracLoc, 
+                                          MultiExprArg Args,
+                                          SourceLocation RBracLoc) {
+    return SemaRef.BuildInstanceMessage(Receiver,
+                                        Receiver->getType(),
+                                        /*SuperLoc=*/SourceLocation(),
+                                        Sel, Method, LBracLoc, SelectorLocs,
+                                        RBracLoc, move(Args));
+  }
+
+  /// \brief Build a new Objective-C ivar reference expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCIvarRefExpr(Expr *BaseArg, ObjCIvarDecl *Ivar,
+                                          SourceLocation IvarLoc,
+                                          bool IsArrow, bool IsFreeIvar) {
+    // FIXME: We lose track of the IsFreeIvar bit.
+    CXXScopeSpec SS;
+    ExprResult Base = getSema().Owned(BaseArg);
+    LookupResult R(getSema(), Ivar->getDeclName(), IvarLoc,
+                   Sema::LookupMemberName);
+    ExprResult Result = getSema().LookupMemberExpr(R, Base, IsArrow,
+                                                         /*FIME:*/IvarLoc,
+                                                         SS, 0,
+                                                         false);
+    if (Result.isInvalid() || Base.isInvalid())
+      return ExprError();
+    
+    if (Result.get())
+      return move(Result);
+    
+    return getSema().BuildMemberReferenceExpr(Base.get(), Base.get()->getType(),
+                                              /*FIXME:*/IvarLoc, IsArrow,
+                                              SS, SourceLocation(),
+                                              /*FirstQualifierInScope=*/0,
+                                              R, 
+                                              /*TemplateArgs=*/0);
+  }
+
+  /// \brief Build a new Objective-C property reference expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCPropertyRefExpr(Expr *BaseArg, 
+                                        ObjCPropertyDecl *Property,
+                                        SourceLocation PropertyLoc) {
+    CXXScopeSpec SS;
+    ExprResult Base = getSema().Owned(BaseArg);
+    LookupResult R(getSema(), Property->getDeclName(), PropertyLoc,
+                   Sema::LookupMemberName);
+    bool IsArrow = false;
+    ExprResult Result = getSema().LookupMemberExpr(R, Base, IsArrow,
+                                                         /*FIME:*/PropertyLoc,
+                                                         SS, 0, false);
+    if (Result.isInvalid() || Base.isInvalid())
+      return ExprError();
+    
+    if (Result.get())
+      return move(Result);
+    
+    return getSema().BuildMemberReferenceExpr(Base.get(), Base.get()->getType(),
+                                              /*FIXME:*/PropertyLoc, IsArrow, 
+                                              SS, SourceLocation(),
+                                              /*FirstQualifierInScope=*/0,
+                                              R, 
+                                              /*TemplateArgs=*/0);
+  }
+  
+  /// \brief Build a new Objective-C property reference expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCPropertyRefExpr(Expr *Base, QualType T,
+                                        ObjCMethodDecl *Getter,
+                                        ObjCMethodDecl *Setter,
+                                        SourceLocation PropertyLoc) {
+    // Since these expressions can only be value-dependent, we do not
+    // need to perform semantic analysis again.
+    return Owned(
+      new (getSema().Context) ObjCPropertyRefExpr(Getter, Setter, T,
+                                                  VK_LValue, OK_ObjCProperty,
+                                                  PropertyLoc, Base));
+  }
+
+  /// \brief Build a new Objective-C "isa" expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildObjCIsaExpr(Expr *BaseArg, SourceLocation IsaLoc,
+                                      bool IsArrow) {
+    CXXScopeSpec SS;
+    ExprResult Base = getSema().Owned(BaseArg);
+    LookupResult R(getSema(), &getSema().Context.Idents.get("isa"), IsaLoc,
+                   Sema::LookupMemberName);
+    ExprResult Result = getSema().LookupMemberExpr(R, Base, IsArrow,
+                                                         /*FIME:*/IsaLoc,
+                                                         SS, 0, false);
+    if (Result.isInvalid() || Base.isInvalid())
+      return ExprError();
+    
+    if (Result.get())
+      return move(Result);
+    
+    return getSema().BuildMemberReferenceExpr(Base.get(), Base.get()->getType(),
+                                              /*FIXME:*/IsaLoc, IsArrow,
+                                              SS, SourceLocation(),
+                                              /*FirstQualifierInScope=*/0,
+                                              R, 
+                                              /*TemplateArgs=*/0);
+  }
+  
+  /// \brief Build a new shuffle vector expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildShuffleVectorExpr(SourceLocation BuiltinLoc,
+                                      MultiExprArg SubExprs,
+                                      SourceLocation RParenLoc) {
+    // Find the declaration for __builtin_shufflevector
+    const IdentifierInfo &Name
+      = SemaRef.Context.Idents.get("__builtin_shufflevector");
+    TranslationUnitDecl *TUDecl = SemaRef.Context.getTranslationUnitDecl();
+    DeclContext::lookup_result Lookup = TUDecl->lookup(DeclarationName(&Name));
+    assert(Lookup.first != Lookup.second && "No __builtin_shufflevector?");
+
+    // Build a reference to the __builtin_shufflevector builtin
+    FunctionDecl *Builtin = cast<FunctionDecl>(*Lookup.first);
+    ExprResult Callee
+      = SemaRef.Owned(new (SemaRef.Context) DeclRefExpr(Builtin, false,
+                                                        Builtin->getType(),
+                                                        VK_LValue, BuiltinLoc));
+    Callee = SemaRef.UsualUnaryConversions(Callee.take());
+    if (Callee.isInvalid())
+      return ExprError();
+
+    // Build the CallExpr
+    unsigned NumSubExprs = SubExprs.size();
+    Expr **Subs = (Expr **)SubExprs.release();
+    ExprResult TheCall = SemaRef.Owned(
+      new (SemaRef.Context) CallExpr(SemaRef.Context, Callee.take(),
+                                                       Subs, NumSubExprs,
+                                                   Builtin->getCallResultType(),
+                            Expr::getValueKindForType(Builtin->getResultType()),
+                                     RParenLoc));
+
+    // Type-check the __builtin_shufflevector expression.
+    return SemaRef.SemaBuiltinShuffleVector(cast<CallExpr>(TheCall.take()));
+  }
+
+  /// \brief Build a new template argument pack expansion.
+  ///
+  /// By default, performs semantic analysis to build a new pack expansion
+  /// for a template argument. Subclasses may override this routine to provide 
+  /// different behavior.
+  TemplateArgumentLoc RebuildPackExpansion(TemplateArgumentLoc Pattern,
+                                           SourceLocation EllipsisLoc,
+                                       llvm::Optional<unsigned> NumExpansions) {
+    switch (Pattern.getArgument().getKind()) {
+    case TemplateArgument::Expression: {
+      ExprResult Result
+        = getSema().CheckPackExpansion(Pattern.getSourceExpression(),
+                                       EllipsisLoc, NumExpansions);
+      if (Result.isInvalid())
+        return TemplateArgumentLoc();
+          
+      return TemplateArgumentLoc(Result.get(), Result.get());
+    }
+        
+    case TemplateArgument::Template:
+      return TemplateArgumentLoc(TemplateArgument(
+                                          Pattern.getArgument().getAsTemplate(),
+                                                  NumExpansions),
+                                 Pattern.getTemplateQualifierLoc(),
+                                 Pattern.getTemplateNameLoc(),
+                                 EllipsisLoc);
+        
+    case TemplateArgument::Null:
+    case TemplateArgument::Integral:
+    case TemplateArgument::Declaration:
+    case TemplateArgument::Pack:
+    case TemplateArgument::TemplateExpansion:
+      llvm_unreachable("Pack expansion pattern has no parameter packs");
+        
+    case TemplateArgument::Type:
+      if (TypeSourceInfo *Expansion 
+            = getSema().CheckPackExpansion(Pattern.getTypeSourceInfo(),
+                                           EllipsisLoc,
+                                           NumExpansions))
+        return TemplateArgumentLoc(TemplateArgument(Expansion->getType()),
+                                   Expansion);
+      break;
+    }
+    
+    return TemplateArgumentLoc();
+  }
+  
+  /// \brief Build a new expression pack expansion.
+  ///
+  /// By default, performs semantic analysis to build a new pack expansion
+  /// for an expression. Subclasses may override this routine to provide 
+  /// different behavior.
+  ExprResult RebuildPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
+                                  llvm::Optional<unsigned> NumExpansions) {
+    return getSema().CheckPackExpansion(Pattern, EllipsisLoc, NumExpansions);
+  }
+
+  /// \brief Build a new atomic operation expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildAtomicExpr(SourceLocation BuiltinLoc,
+                               MultiExprArg SubExprs,
+                               QualType RetTy,
+                               AtomicExpr::AtomicOp Op,
+                               SourceLocation RParenLoc) {
+    // Just create the expression; there is not any interesting semantic
+    // analysis here because we can't actually build an AtomicExpr until
+    // we are sure it is semantically sound.
+    unsigned NumSubExprs = SubExprs.size();
+    Expr **Subs = (Expr **)SubExprs.release();
+    return new (SemaRef.Context) AtomicExpr(BuiltinLoc, Subs,
+                                            NumSubExprs, RetTy, Op,
+                                            RParenLoc);
+  }
+
+private:
+  TypeLoc TransformTypeInObjectScope(TypeLoc TL,
+                                     QualType ObjectType,
+                                     NamedDecl *FirstQualifierInScope,
+                                     CXXScopeSpec &SS);
+
+  TypeSourceInfo *TransformTypeInObjectScope(TypeSourceInfo *TSInfo,
+                                             QualType ObjectType,
+                                             NamedDecl *FirstQualifierInScope,
+                                             CXXScopeSpec &SS);
+};
+
+template<typename Derived>
+StmtResult TreeTransform<Derived>::TransformStmt(Stmt *S) {
+  if (!S)
+    return SemaRef.Owned(S);
+
+  switch (S->getStmtClass()) {
+  case Stmt::NoStmtClass: break;
+
+  // Transform individual statement nodes
+#define STMT(Node, Parent)                                              \
+  case Stmt::Node##Class: return getDerived().Transform##Node(cast<Node>(S));
+#define ABSTRACT_STMT(Node)
+#define EXPR(Node, Parent)
+#include "clang/AST/StmtNodes.inc"
+
+  // Transform expressions by calling TransformExpr.
+#define STMT(Node, Parent)
+#define ABSTRACT_STMT(Stmt)
+#define EXPR(Node, Parent) case Stmt::Node##Class:
+#include "clang/AST/StmtNodes.inc"
+    {
+      ExprResult E = getDerived().TransformExpr(cast<Expr>(S));
+      if (E.isInvalid())
+        return StmtError();
+
+      return getSema().ActOnExprStmt(getSema().MakeFullExpr(E.take()));
+    }
+  }
+
+  return SemaRef.Owned(S);
+}
+
+
+template<typename Derived>
+ExprResult TreeTransform<Derived>::TransformExpr(Expr *E) {
+  if (!E)
+    return SemaRef.Owned(E);
+
+  switch (E->getStmtClass()) {
+    case Stmt::NoStmtClass: break;
+#define STMT(Node, Parent) case Stmt::Node##Class: break;
+#define ABSTRACT_STMT(Stmt)
+#define EXPR(Node, Parent)                                              \
+    case Stmt::Node##Class: return getDerived().Transform##Node(cast<Node>(E));
+#include "clang/AST/StmtNodes.inc"
+  }
+
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+bool TreeTransform<Derived>::TransformExprs(Expr **Inputs, 
+                                            unsigned NumInputs, 
+                                            bool IsCall,
+                                      SmallVectorImpl<Expr *> &Outputs,
+                                            bool *ArgChanged) {
+  for (unsigned I = 0; I != NumInputs; ++I) {
+    // If requested, drop call arguments that need to be dropped.
+    if (IsCall && getDerived().DropCallArgument(Inputs[I])) {
+      if (ArgChanged)
+        *ArgChanged = true;
+      
+      break;
+    }
+    
+    if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(Inputs[I])) {
+      Expr *Pattern = Expansion->getPattern();
+        
+      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      getSema().collectUnexpandedParameterPacks(Pattern, Unexpanded);
+      assert(!Unexpanded.empty() && "Pack expansion without parameter packs?");
+      
+      // Determine whether the set of unexpanded parameter packs can and should
+      // be expanded.
+      bool Expand = true;
+      bool RetainExpansion = false;
+      llvm::Optional<unsigned> OrigNumExpansions
+        = Expansion->getNumExpansions();
+      llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
+      if (getDerived().TryExpandParameterPacks(Expansion->getEllipsisLoc(),
+                                               Pattern->getSourceRange(),
+                                               Unexpanded,
+                                               Expand, RetainExpansion,
+                                               NumExpansions))
+        return true;
+        
+      if (!Expand) {
+        // The transform has determined that we should perform a simple
+        // transformation on the pack expansion, producing another pack 
+        // expansion.
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), -1);
+        ExprResult OutPattern = getDerived().TransformExpr(Pattern);
+        if (OutPattern.isInvalid())
+          return true;
+        
+        ExprResult Out = getDerived().RebuildPackExpansion(OutPattern.get(), 
+                                                Expansion->getEllipsisLoc(),
+                                                           NumExpansions);
+        if (Out.isInvalid())
+          return true;
+        
+        if (ArgChanged)
+          *ArgChanged = true;
+        Outputs.push_back(Out.get());
+        continue;
+      }
+
+      // Record right away that the argument was changed.  This needs
+      // to happen even if the array expands to nothing.
+      if (ArgChanged) *ArgChanged = true;
+      
+      // The transform has determined that we should perform an elementwise
+      // expansion of the pattern. Do so.
+      for (unsigned I = 0; I != *NumExpansions; ++I) {
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), I);
+        ExprResult Out = getDerived().TransformExpr(Pattern);
+        if (Out.isInvalid())
+          return true;
+
+        if (Out.get()->containsUnexpandedParameterPack()) {
+          Out = RebuildPackExpansion(Out.get(), Expansion->getEllipsisLoc(),
+                                     OrigNumExpansions);
+          if (Out.isInvalid())
+            return true;
+        }
+        
+        Outputs.push_back(Out.get());
+      }
+        
+      continue;
+    }
+    
+    ExprResult Result = getDerived().TransformExpr(Inputs[I]);
+    if (Result.isInvalid())
+      return true;
+    
+    if (Result.get() != Inputs[I] && ArgChanged)
+      *ArgChanged = true;
+    
+    Outputs.push_back(Result.get());    
+  }
+  
+  return false;
+}
+
+template<typename Derived>
+NestedNameSpecifierLoc
+TreeTransform<Derived>::TransformNestedNameSpecifierLoc(
+                                                    NestedNameSpecifierLoc NNS,
+                                                     QualType ObjectType,
+                                             NamedDecl *FirstQualifierInScope) {
+  SmallVector<NestedNameSpecifierLoc, 4> Qualifiers;
+  for (NestedNameSpecifierLoc Qualifier = NNS; Qualifier; 
+       Qualifier = Qualifier.getPrefix())
+    Qualifiers.push_back(Qualifier);
+
+  CXXScopeSpec SS;
+  while (!Qualifiers.empty()) {
+    NestedNameSpecifierLoc Q = Qualifiers.pop_back_val();
+    NestedNameSpecifier *QNNS = Q.getNestedNameSpecifier();
+    
+    switch (QNNS->getKind()) {
+    case NestedNameSpecifier::Identifier:
+      if (SemaRef.BuildCXXNestedNameSpecifier(/*Scope=*/0, 
+                                              *QNNS->getAsIdentifier(),
+                                              Q.getLocalBeginLoc(), 
+                                              Q.getLocalEndLoc(),
+                                              ObjectType, false, SS, 
+                                              FirstQualifierInScope, false))
+        return NestedNameSpecifierLoc();
+        
+      break;
+      
+    case NestedNameSpecifier::Namespace: {
+      NamespaceDecl *NS
+        = cast_or_null<NamespaceDecl>(
+                                    getDerived().TransformDecl(
+                                                          Q.getLocalBeginLoc(),
+                                                       QNNS->getAsNamespace()));
+      SS.Extend(SemaRef.Context, NS, Q.getLocalBeginLoc(), Q.getLocalEndLoc());
+      break;
+    }
+      
+    case NestedNameSpecifier::NamespaceAlias: {
+      NamespaceAliasDecl *Alias
+        = cast_or_null<NamespaceAliasDecl>(
+                      getDerived().TransformDecl(Q.getLocalBeginLoc(),
+                                                 QNNS->getAsNamespaceAlias()));
+      SS.Extend(SemaRef.Context, Alias, Q.getLocalBeginLoc(), 
+                Q.getLocalEndLoc());
+      break;
+    }
+      
+    case NestedNameSpecifier::Global:
+      // There is no meaningful transformation that one could perform on the
+      // global scope.
+      SS.MakeGlobal(SemaRef.Context, Q.getBeginLoc());
+      break;
+      
+    case NestedNameSpecifier::TypeSpecWithTemplate:
+    case NestedNameSpecifier::TypeSpec: {
+      TypeLoc TL = TransformTypeInObjectScope(Q.getTypeLoc(), ObjectType,
+                                              FirstQualifierInScope, SS);
+      
+      if (!TL)
+        return NestedNameSpecifierLoc();
+      
+      if (TL.getType()->isDependentType() || TL.getType()->isRecordType() ||
+          (SemaRef.getLangOpts().CPlusPlus0x && 
+           TL.getType()->isEnumeralType())) {
+        assert(!TL.getType().hasLocalQualifiers() && 
+               "Can't get cv-qualifiers here");
+        if (TL.getType()->isEnumeralType())
+          SemaRef.Diag(TL.getBeginLoc(),
+                       diag::warn_cxx98_compat_enum_nested_name_spec);
+        SS.Extend(SemaRef.Context, /*FIXME:*/SourceLocation(), TL,
+                  Q.getLocalEndLoc());
+        break;
+      }
+      // If the nested-name-specifier is an invalid type def, don't emit an
+      // error because a previous error should have already been emitted.
+      TypedefTypeLoc* TTL = dyn_cast<TypedefTypeLoc>(&TL);
+      if (!TTL || !TTL->getTypedefNameDecl()->isInvalidDecl()) {
+        SemaRef.Diag(TL.getBeginLoc(), diag::err_nested_name_spec_non_tag) 
+          << TL.getType() << SS.getRange();
+      }
+      return NestedNameSpecifierLoc();
+    }
+    }
+    
+    // The qualifier-in-scope and object type only apply to the leftmost entity.
+    FirstQualifierInScope = 0;
+    ObjectType = QualType();
+  }
+  
+  // Don't rebuild the nested-name-specifier if we don't have to.
+  if (SS.getScopeRep() == NNS.getNestedNameSpecifier() && 
+      !getDerived().AlwaysRebuild())
+    return NNS;
+  
+  // If we can re-use the source-location data from the original 
+  // nested-name-specifier, do so.
+  if (SS.location_size() == NNS.getDataLength() &&
+      memcmp(SS.location_data(), NNS.getOpaqueData(), SS.location_size()) == 0)
+    return NestedNameSpecifierLoc(SS.getScopeRep(), NNS.getOpaqueData());
+
+  // Allocate new nested-name-specifier location information.
+  return SS.getWithLocInContext(SemaRef.Context);
+}
+
+template<typename Derived>
+DeclarationNameInfo
+TreeTransform<Derived>
+::TransformDeclarationNameInfo(const DeclarationNameInfo &NameInfo) {
+  DeclarationName Name = NameInfo.getName();
+  if (!Name)
+    return DeclarationNameInfo();
+
+  switch (Name.getNameKind()) {
+  case DeclarationName::Identifier:
+  case DeclarationName::ObjCZeroArgSelector:
+  case DeclarationName::ObjCOneArgSelector:
+  case DeclarationName::ObjCMultiArgSelector:
+  case DeclarationName::CXXOperatorName:
+  case DeclarationName::CXXLiteralOperatorName:
+  case DeclarationName::CXXUsingDirective:
+    return NameInfo;
+
+  case DeclarationName::CXXConstructorName:
+  case DeclarationName::CXXDestructorName:
+  case DeclarationName::CXXConversionFunctionName: {
+    TypeSourceInfo *NewTInfo;
+    CanQualType NewCanTy;
+    if (TypeSourceInfo *OldTInfo = NameInfo.getNamedTypeInfo()) {
+      NewTInfo = getDerived().TransformType(OldTInfo);
+      if (!NewTInfo)
+        return DeclarationNameInfo();
+      NewCanTy = SemaRef.Context.getCanonicalType(NewTInfo->getType());
+    }
+    else {
+      NewTInfo = 0;
+      TemporaryBase Rebase(*this, NameInfo.getLoc(), Name);
+      QualType NewT = getDerived().TransformType(Name.getCXXNameType());
+      if (NewT.isNull())
+        return DeclarationNameInfo();
+      NewCanTy = SemaRef.Context.getCanonicalType(NewT);
+    }
+
+    DeclarationName NewName
+      = SemaRef.Context.DeclarationNames.getCXXSpecialName(Name.getNameKind(),
+                                                           NewCanTy);
+    DeclarationNameInfo NewNameInfo(NameInfo);
+    NewNameInfo.setName(NewName);
+    NewNameInfo.setNamedTypeInfo(NewTInfo);
+    return NewNameInfo;
+  }
+  }
+
+  llvm_unreachable("Unknown name kind.");
+}
+
+template<typename Derived>
+TemplateName
+TreeTransform<Derived>::TransformTemplateName(CXXScopeSpec &SS,
+                                              TemplateName Name,
+                                              SourceLocation NameLoc,
+                                              QualType ObjectType,
+                                              NamedDecl *FirstQualifierInScope) {
+  if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) {
+    TemplateDecl *Template = QTN->getTemplateDecl();
+    assert(Template && "qualified template name must refer to a template");
+    
+    TemplateDecl *TransTemplate
+      = cast_or_null<TemplateDecl>(getDerived().TransformDecl(NameLoc, 
+                                                              Template));
+    if (!TransTemplate)
+      return TemplateName();
+      
+    if (!getDerived().AlwaysRebuild() &&
+        SS.getScopeRep() == QTN->getQualifier() &&
+        TransTemplate == Template)
+      return Name;
+      
+    return getDerived().RebuildTemplateName(SS, QTN->hasTemplateKeyword(),
+                                            TransTemplate);
+  }
+  
+  if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) {
+    if (SS.getScopeRep()) {
+      // These apply to the scope specifier, not the template.
+      ObjectType = QualType();
+      FirstQualifierInScope = 0;
+    }      
+    
+    if (!getDerived().AlwaysRebuild() &&
+        SS.getScopeRep() == DTN->getQualifier() &&
+        ObjectType.isNull())
+      return Name;
+    
+    if (DTN->isIdentifier()) {
+      return getDerived().RebuildTemplateName(SS,
+                                              *DTN->getIdentifier(), 
+                                              NameLoc,
+                                              ObjectType,
+                                              FirstQualifierInScope);
+    }
+    
+    return getDerived().RebuildTemplateName(SS, DTN->getOperator(), NameLoc,
+                                            ObjectType);
+  }
+  
+  if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
+    TemplateDecl *TransTemplate
+      = cast_or_null<TemplateDecl>(getDerived().TransformDecl(NameLoc, 
+                                                              Template));
+    if (!TransTemplate)
+      return TemplateName();
+    
+    if (!getDerived().AlwaysRebuild() &&
+        TransTemplate == Template)
+      return Name;
+    
+    return TemplateName(TransTemplate);
+  }
+  
+  if (SubstTemplateTemplateParmPackStorage *SubstPack
+      = Name.getAsSubstTemplateTemplateParmPack()) {
+    TemplateTemplateParmDecl *TransParam
+    = cast_or_null<TemplateTemplateParmDecl>(
+            getDerived().TransformDecl(NameLoc, SubstPack->getParameterPack()));
+    if (!TransParam)
+      return TemplateName();
+    
+    if (!getDerived().AlwaysRebuild() &&
+        TransParam == SubstPack->getParameterPack())
+      return Name;
+    
+    return getDerived().RebuildTemplateName(TransParam, 
+                                            SubstPack->getArgumentPack());
+  }
+  
+  // These should be getting filtered out before they reach the AST.
+  llvm_unreachable("overloaded function decl survived to here");
+}
+
+template<typename Derived>
+void TreeTransform<Derived>::InventTemplateArgumentLoc(
+                                         const TemplateArgument &Arg,
+                                         TemplateArgumentLoc &Output) {
+  SourceLocation Loc = getDerived().getBaseLocation();
+  switch (Arg.getKind()) {
+  case TemplateArgument::Null:
+    llvm_unreachable("null template argument in TreeTransform");
+    break;
+
+  case TemplateArgument::Type:
+    Output = TemplateArgumentLoc(Arg,
+               SemaRef.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc));
+                                            
+    break;
+
+  case TemplateArgument::Template:
+  case TemplateArgument::TemplateExpansion: {
+    NestedNameSpecifierLocBuilder Builder;
+    TemplateName Template = Arg.getAsTemplate();
+    if (DependentTemplateName *DTN = Template.getAsDependentTemplateName())
+      Builder.MakeTrivial(SemaRef.Context, DTN->getQualifier(), Loc);
+    else if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
+      Builder.MakeTrivial(SemaRef.Context, QTN->getQualifier(), Loc);
+        
+    if (Arg.getKind() == TemplateArgument::Template)
+      Output = TemplateArgumentLoc(Arg, 
+                                   Builder.getWithLocInContext(SemaRef.Context),
+                                   Loc);
+    else
+      Output = TemplateArgumentLoc(Arg, 
+                                   Builder.getWithLocInContext(SemaRef.Context),
+                                   Loc, Loc);
+    
+    break;
+  }
+
+  case TemplateArgument::Expression:
+    Output = TemplateArgumentLoc(Arg, Arg.getAsExpr());
+    break;
+
+  case TemplateArgument::Declaration:
+  case TemplateArgument::Integral:
+  case TemplateArgument::Pack:
+    Output = TemplateArgumentLoc(Arg, TemplateArgumentLocInfo());
+    break;
+  }
+}
+
+template<typename Derived>
+bool TreeTransform<Derived>::TransformTemplateArgument(
+                                         const TemplateArgumentLoc &Input,
+                                         TemplateArgumentLoc &Output) {
+  const TemplateArgument &Arg = Input.getArgument();
+  switch (Arg.getKind()) {
+  case TemplateArgument::Null:
+  case TemplateArgument::Integral:
+    Output = Input;
+    return false;
+
+  case TemplateArgument::Type: {
+    TypeSourceInfo *DI = Input.getTypeSourceInfo();
+    if (DI == NULL)
+      DI = InventTypeSourceInfo(Input.getArgument().getAsType());
+
+    DI = getDerived().TransformType(DI);
+    if (!DI) return true;
+
+    Output = TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
+    return false;
+  }
+
+  case TemplateArgument::Declaration: {
+    // FIXME: we should never have to transform one of these.
+    DeclarationName Name;
+    if (NamedDecl *ND = dyn_cast<NamedDecl>(Arg.getAsDecl()))
+      Name = ND->getDeclName();
+    TemporaryBase Rebase(*this, Input.getLocation(), Name);
+    Decl *D = getDerived().TransformDecl(Input.getLocation(), Arg.getAsDecl());
+    if (!D) return true;
+
+    Expr *SourceExpr = Input.getSourceDeclExpression();
+    if (SourceExpr) {
+      EnterExpressionEvaluationContext Unevaluated(getSema(),
+                                                   Sema::ConstantEvaluated);
+      ExprResult E = getDerived().TransformExpr(SourceExpr);
+      E = SemaRef.ActOnConstantExpression(E);
+      SourceExpr = (E.isInvalid() ? 0 : E.take());
+    }
+
+    Output = TemplateArgumentLoc(TemplateArgument(D), SourceExpr);
+    return false;
+  }
+
+  case TemplateArgument::Template: {
+    NestedNameSpecifierLoc QualifierLoc = Input.getTemplateQualifierLoc();
+    if (QualifierLoc) {
+      QualifierLoc = getDerived().TransformNestedNameSpecifierLoc(QualifierLoc);
+      if (!QualifierLoc)
+        return true;
+    }
+    
+    CXXScopeSpec SS;
+    SS.Adopt(QualifierLoc);
+    TemplateName Template
+      = getDerived().TransformTemplateName(SS, Arg.getAsTemplate(),
+                                           Input.getTemplateNameLoc());
+    if (Template.isNull())
+      return true;
+    
+    Output = TemplateArgumentLoc(TemplateArgument(Template), QualifierLoc,
+                                 Input.getTemplateNameLoc());
+    return false;
+  }
+
+  case TemplateArgument::TemplateExpansion:
+    llvm_unreachable("Caller should expand pack expansions");
+
+  case TemplateArgument::Expression: {
+    // Template argument expressions are constant expressions.
+    EnterExpressionEvaluationContext Unevaluated(getSema(),
+                                                 Sema::ConstantEvaluated);
+
+    Expr *InputExpr = Input.getSourceExpression();
+    if (!InputExpr) InputExpr = Input.getArgument().getAsExpr();
+
+    ExprResult E = getDerived().TransformExpr(InputExpr);
+    E = SemaRef.ActOnConstantExpression(E);
+    if (E.isInvalid()) return true;
+    Output = TemplateArgumentLoc(TemplateArgument(E.take()), E.take());
+    return false;
+  }
+
+  case TemplateArgument::Pack: {
+    SmallVector<TemplateArgument, 4> TransformedArgs;
+    TransformedArgs.reserve(Arg.pack_size());
+    for (TemplateArgument::pack_iterator A = Arg.pack_begin(),
+                                      AEnd = Arg.pack_end();
+         A != AEnd; ++A) {
+
+      // FIXME: preserve source information here when we start
+      // caring about parameter packs.
+
+      TemplateArgumentLoc InputArg;
+      TemplateArgumentLoc OutputArg;
+      getDerived().InventTemplateArgumentLoc(*A, InputArg);
+      if (getDerived().TransformTemplateArgument(InputArg, OutputArg))
+        return true;
+
+      TransformedArgs.push_back(OutputArg.getArgument());
+    }
+
+    TemplateArgument *TransformedArgsPtr
+      = new (getSema().Context) TemplateArgument[TransformedArgs.size()];
+    std::copy(TransformedArgs.begin(), TransformedArgs.end(),
+              TransformedArgsPtr);
+    Output = TemplateArgumentLoc(TemplateArgument(TransformedArgsPtr, 
+                                                  TransformedArgs.size()), 
+                                 Input.getLocInfo());
+    return false;
+  }
+  }
+
+  // Work around bogus GCC warning
+  return true;
+}
+
+/// \brief Iterator adaptor that invents template argument location information
+/// for each of the template arguments in its underlying iterator.
+template<typename Derived, typename InputIterator>
+class TemplateArgumentLocInventIterator {
+  TreeTransform<Derived> &Self;
+  InputIterator Iter;
+  
+public:
+  typedef TemplateArgumentLoc value_type;
+  typedef TemplateArgumentLoc reference;
+  typedef typename std::iterator_traits<InputIterator>::difference_type
+    difference_type;
+  typedef std::input_iterator_tag iterator_category;
+  
+  class pointer {
+    TemplateArgumentLoc Arg;
+    
+  public:
+    explicit pointer(TemplateArgumentLoc Arg) : Arg(Arg) { }
+    
+    const TemplateArgumentLoc *operator->() const { return &Arg; }
+  };
+  
+  TemplateArgumentLocInventIterator() { }
+  
+  explicit TemplateArgumentLocInventIterator(TreeTransform<Derived> &Self,
+                                             InputIterator Iter)
+    : Self(Self), Iter(Iter) { }
+  
+  TemplateArgumentLocInventIterator &operator++() {
+    ++Iter;
+    return *this;
+  }
+  
+  TemplateArgumentLocInventIterator operator++(int) {
+    TemplateArgumentLocInventIterator Old(*this);
+    ++(*this);
+    return Old;
+  }
+  
+  reference operator*() const {
+    TemplateArgumentLoc Result;
+    Self.InventTemplateArgumentLoc(*Iter, Result);
+    return Result;
+  }
+  
+  pointer operator->() const { return pointer(**this); }
+  
+  friend bool operator==(const TemplateArgumentLocInventIterator &X,
+                         const TemplateArgumentLocInventIterator &Y) {
+    return X.Iter == Y.Iter;
+  }
+
+  friend bool operator!=(const TemplateArgumentLocInventIterator &X,
+                         const TemplateArgumentLocInventIterator &Y) {
+    return X.Iter != Y.Iter;
+  }
+};
+  
+template<typename Derived>
+template<typename InputIterator>
+bool TreeTransform<Derived>::TransformTemplateArguments(InputIterator First,
+                                                        InputIterator Last,
+                                            TemplateArgumentListInfo &Outputs) {
+  for (; First != Last; ++First) {
+    TemplateArgumentLoc Out;
+    TemplateArgumentLoc In = *First;
+    
+    if (In.getArgument().getKind() == TemplateArgument::Pack) {
+      // Unpack argument packs, which we translate them into separate
+      // arguments.
+      // FIXME: We could do much better if we could guarantee that the
+      // TemplateArgumentLocInfo for the pack expansion would be usable for
+      // all of the template arguments in the argument pack.
+      typedef TemplateArgumentLocInventIterator<Derived, 
+                                                TemplateArgument::pack_iterator>
+        PackLocIterator;
+      if (TransformTemplateArguments(PackLocIterator(*this, 
+                                                 In.getArgument().pack_begin()),
+                                     PackLocIterator(*this,
+                                                   In.getArgument().pack_end()),
+                                     Outputs))
+        return true;
+      
+      continue;
+    }
+    
+    if (In.getArgument().isPackExpansion()) {
+      // We have a pack expansion, for which we will be substituting into
+      // the pattern.
+      SourceLocation Ellipsis;
+      llvm::Optional<unsigned> OrigNumExpansions;
+      TemplateArgumentLoc Pattern
+        = In.getPackExpansionPattern(Ellipsis, OrigNumExpansions, 
+                                     getSema().Context);
+      
+      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      getSema().collectUnexpandedParameterPacks(Pattern, Unexpanded);
+      assert(!Unexpanded.empty() && "Pack expansion without parameter packs?");
+      
+      // Determine whether the set of unexpanded parameter packs can and should
+      // be expanded.
+      bool Expand = true;
+      bool RetainExpansion = false;
+      llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
+      if (getDerived().TryExpandParameterPacks(Ellipsis,
+                                               Pattern.getSourceRange(),
+                                               Unexpanded,
+                                               Expand, 
+                                               RetainExpansion,
+                                               NumExpansions))
+        return true;
+      
+      if (!Expand) {
+        // The transform has determined that we should perform a simple
+        // transformation on the pack expansion, producing another pack 
+        // expansion.
+        TemplateArgumentLoc OutPattern;
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), -1);
+        if (getDerived().TransformTemplateArgument(Pattern, OutPattern))
+          return true;
+                
+        Out = getDerived().RebuildPackExpansion(OutPattern, Ellipsis,
+                                                NumExpansions);
+        if (Out.getArgument().isNull())
+          return true;
+        
+        Outputs.addArgument(Out);
+        continue;
+      }
+      
+      // The transform has determined that we should perform an elementwise
+      // expansion of the pattern. Do so.
+      for (unsigned I = 0; I != *NumExpansions; ++I) {
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), I);
+
+        if (getDerived().TransformTemplateArgument(Pattern, Out))
+          return true;
+        
+        if (Out.getArgument().containsUnexpandedParameterPack()) {
+          Out = getDerived().RebuildPackExpansion(Out, Ellipsis,
+                                                  OrigNumExpansions);
+          if (Out.getArgument().isNull())
+            return true;
+        }
+          
+        Outputs.addArgument(Out);
+      }
+      
+      // If we're supposed to retain a pack expansion, do so by temporarily
+      // forgetting the partially-substituted parameter pack.
+      if (RetainExpansion) {
+        ForgetPartiallySubstitutedPackRAII Forget(getDerived());
+        
+        if (getDerived().TransformTemplateArgument(Pattern, Out))
+          return true;
+        
+        Out = getDerived().RebuildPackExpansion(Out, Ellipsis,
+                                                OrigNumExpansions);
+        if (Out.getArgument().isNull())
+          return true;
+        
+        Outputs.addArgument(Out);
+      }
+      
+      continue;
+    }
+    
+    // The simple case: 
+    if (getDerived().TransformTemplateArgument(In, Out))
+      return true;
+    
+    Outputs.addArgument(Out);
+  }
+  
+  return false;
+
+}
+
+//===----------------------------------------------------------------------===//
+// Type transformation
+//===----------------------------------------------------------------------===//
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformType(QualType T) {
+  if (getDerived().AlreadyTransformed(T))
+    return T;
+
+  // Temporary workaround.  All of these transformations should
+  // eventually turn into transformations on TypeLocs.
+  TypeSourceInfo *DI = getSema().Context.getTrivialTypeSourceInfo(T,
+                                                getDerived().getBaseLocation());
+  
+  TypeSourceInfo *NewDI = getDerived().TransformType(DI);
+
+  if (!NewDI)
+    return QualType();
+
+  return NewDI->getType();
+}
+
+template<typename Derived>
+TypeSourceInfo *TreeTransform<Derived>::TransformType(TypeSourceInfo *DI) {
+  // Refine the base location to the type's location.
+  TemporaryBase Rebase(*this, DI->getTypeLoc().getBeginLoc(),
+                       getDerived().getBaseEntity());
+  if (getDerived().AlreadyTransformed(DI->getType()))
+    return DI;
+
+  TypeLocBuilder TLB;
+
+  TypeLoc TL = DI->getTypeLoc();
+  TLB.reserve(TL.getFullDataSize());
+
+  QualType Result = getDerived().TransformType(TLB, TL);
+  if (Result.isNull())
+    return 0;
+
+  return TLB.getTypeSourceInfo(SemaRef.Context, Result);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformType(TypeLocBuilder &TLB, TypeLoc T) {
+  switch (T.getTypeLocClass()) {
+#define ABSTRACT_TYPELOC(CLASS, PARENT)
+#define TYPELOC(CLASS, PARENT) \
+  case TypeLoc::CLASS: \
+    return getDerived().Transform##CLASS##Type(TLB, cast<CLASS##TypeLoc>(T));
+#include "clang/AST/TypeLocNodes.def"
+  }
+
+  llvm_unreachable("unhandled type loc!");
+}
+
+/// FIXME: By default, this routine adds type qualifiers only to types
+/// that can have qualifiers, and silently suppresses those qualifiers
+/// that are not permitted (e.g., qualifiers on reference or function
+/// types). This is the right thing for template instantiation, but
+/// probably not for other clients.
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformQualifiedType(TypeLocBuilder &TLB,
+                                               QualifiedTypeLoc T) {
+  Qualifiers Quals = T.getType().getLocalQualifiers();
+
+  QualType Result = getDerived().TransformType(TLB, T.getUnqualifiedLoc());
+  if (Result.isNull())
+    return QualType();
+
+  // Silently suppress qualifiers if the result type can't be qualified.
+  // FIXME: this is the right thing for template instantiation, but
+  // probably not for other clients.
+  if (Result->isFunctionType() || Result->isReferenceType())
+    return Result;
+
+  // Suppress Objective-C lifetime qualifiers if they don't make sense for the
+  // resulting type.
+  if (Quals.hasObjCLifetime()) {
+    if (!Result->isObjCLifetimeType() && !Result->isDependentType())
+      Quals.removeObjCLifetime();
+    else if (Result.getObjCLifetime()) {
+      // Objective-C ARC: 
+      //   A lifetime qualifier applied to a substituted template parameter
+      //   overrides the lifetime qualifier from the template argument.
+      if (const SubstTemplateTypeParmType *SubstTypeParam 
+                                = dyn_cast<SubstTemplateTypeParmType>(Result)) {
+        QualType Replacement = SubstTypeParam->getReplacementType();
+        Qualifiers Qs = Replacement.getQualifiers();
+        Qs.removeObjCLifetime();
+        Replacement 
+          = SemaRef.Context.getQualifiedType(Replacement.getUnqualifiedType(),
+                                             Qs);
+        Result = SemaRef.Context.getSubstTemplateTypeParmType(
+                                        SubstTypeParam->getReplacedParameter(), 
+                                                              Replacement);
+        TLB.TypeWasModifiedSafely(Result);
+      } else {
+        // Otherwise, complain about the addition of a qualifier to an
+        // already-qualified type.
+        SourceRange R = TLB.getTemporaryTypeLoc(Result).getSourceRange();
+        SemaRef.Diag(R.getBegin(), diag::err_attr_objc_ownership_redundant)
+          << Result << R;
+        
+        Quals.removeObjCLifetime();
+      }
+    }
+  }
+  if (!Quals.empty()) {
+    Result = SemaRef.BuildQualifiedType(Result, T.getBeginLoc(), Quals);
+    TLB.push<QualifiedTypeLoc>(Result);
+    // No location information to preserve.
+  }
+
+  return Result;
+}
+
+template<typename Derived>
+TypeLoc
+TreeTransform<Derived>::TransformTypeInObjectScope(TypeLoc TL,
+                                                   QualType ObjectType,
+                                                   NamedDecl *UnqualLookup,
+                                                   CXXScopeSpec &SS) {
+  QualType T = TL.getType();
+  if (getDerived().AlreadyTransformed(T))
+    return TL;
+  
+  TypeLocBuilder TLB;
+  QualType Result;
+  
+  if (isa<TemplateSpecializationType>(T)) {
+    TemplateSpecializationTypeLoc SpecTL
+      = cast<TemplateSpecializationTypeLoc>(TL);
+    
+    TemplateName Template =
+      getDerived().TransformTemplateName(SS,
+                                         SpecTL.getTypePtr()->getTemplateName(),
+                                         SpecTL.getTemplateNameLoc(),
+                                         ObjectType, UnqualLookup);
+    if (Template.isNull()) 
+      return TypeLoc();
+    
+    Result = getDerived().TransformTemplateSpecializationType(TLB, SpecTL, 
+                                                              Template);
+  } else if (isa<DependentTemplateSpecializationType>(T)) {
+    DependentTemplateSpecializationTypeLoc SpecTL
+      = cast<DependentTemplateSpecializationTypeLoc>(TL);
+    
+    TemplateName Template
+      = getDerived().RebuildTemplateName(SS, 
+                                         *SpecTL.getTypePtr()->getIdentifier(), 
+                                         SpecTL.getTemplateNameLoc(),
+                                         ObjectType, UnqualLookup);
+    if (Template.isNull())
+      return TypeLoc();
+    
+    Result = getDerived().TransformDependentTemplateSpecializationType(TLB, 
+                                                                       SpecTL,
+                                                                     Template,
+                                                                       SS);
+  } else {
+    // Nothing special needs to be done for these.
+    Result = getDerived().TransformType(TLB, TL);
+  }
+  
+  if (Result.isNull()) 
+    return TypeLoc();
+  
+  return TLB.getTypeSourceInfo(SemaRef.Context, Result)->getTypeLoc();
+}
+
+template<typename Derived>
+TypeSourceInfo *
+TreeTransform<Derived>::TransformTypeInObjectScope(TypeSourceInfo *TSInfo,
+                                                   QualType ObjectType,
+                                                   NamedDecl *UnqualLookup,
+                                                   CXXScopeSpec &SS) {
+  // FIXME: Painfully copy-paste from the above!
+  
+  QualType T = TSInfo->getType();
+  if (getDerived().AlreadyTransformed(T))
+    return TSInfo;
+  
+  TypeLocBuilder TLB;
+  QualType Result;
+  
+  TypeLoc TL = TSInfo->getTypeLoc();
+  if (isa<TemplateSpecializationType>(T)) {
+    TemplateSpecializationTypeLoc SpecTL
+      = cast<TemplateSpecializationTypeLoc>(TL);
+    
+    TemplateName Template
+    = getDerived().TransformTemplateName(SS,
+                                         SpecTL.getTypePtr()->getTemplateName(),
+                                         SpecTL.getTemplateNameLoc(),
+                                         ObjectType, UnqualLookup);
+    if (Template.isNull()) 
+      return 0;
+    
+    Result = getDerived().TransformTemplateSpecializationType(TLB, SpecTL, 
+                                                              Template);
+  } else if (isa<DependentTemplateSpecializationType>(T)) {
+    DependentTemplateSpecializationTypeLoc SpecTL
+      = cast<DependentTemplateSpecializationTypeLoc>(TL);
+    
+    TemplateName Template
+      = getDerived().RebuildTemplateName(SS, 
+                                         *SpecTL.getTypePtr()->getIdentifier(), 
+                                         SpecTL.getTemplateNameLoc(),
+                                         ObjectType, UnqualLookup);
+    if (Template.isNull())
+      return 0;
+    
+    Result = getDerived().TransformDependentTemplateSpecializationType(TLB, 
+                                                                       SpecTL,
+                                                                       Template,
+                                                                       SS);
+  } else {
+    // Nothing special needs to be done for these.
+    Result = getDerived().TransformType(TLB, TL);
+  }
+  
+  if (Result.isNull()) 
+    return 0;
+  
+  return TLB.getTypeSourceInfo(SemaRef.Context, Result);
+}
+
+template <class TyLoc> static inline
+QualType TransformTypeSpecType(TypeLocBuilder &TLB, TyLoc T) {
+  TyLoc NewT = TLB.push<TyLoc>(T.getType());
+  NewT.setNameLoc(T.getNameLoc());
+  return T.getType();
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformBuiltinType(TypeLocBuilder &TLB,
+                                                      BuiltinTypeLoc T) {
+  BuiltinTypeLoc NewT = TLB.push<BuiltinTypeLoc>(T.getType());
+  NewT.setBuiltinLoc(T.getBuiltinLoc());
+  if (T.needsExtraLocalData())
+    NewT.getWrittenBuiltinSpecs() = T.getWrittenBuiltinSpecs();
+  return T.getType();
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformComplexType(TypeLocBuilder &TLB,
+                                                      ComplexTypeLoc T) {
+  // FIXME: recurse?
+  return TransformTypeSpecType(TLB, T);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformPointerType(TypeLocBuilder &TLB,
+                                                      PointerTypeLoc TL) {
+  QualType PointeeType                                      
+    = getDerived().TransformType(TLB, TL.getPointeeLoc());  
+  if (PointeeType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (PointeeType->getAs<ObjCObjectType>()) {
+    // A dependent pointer type 'T *' has is being transformed such
+    // that an Objective-C class type is being replaced for 'T'. The
+    // resulting pointer type is an ObjCObjectPointerType, not a
+    // PointerType.
+    Result = SemaRef.Context.getObjCObjectPointerType(PointeeType);
+    
+    ObjCObjectPointerTypeLoc NewT = TLB.push<ObjCObjectPointerTypeLoc>(Result);
+    NewT.setStarLoc(TL.getStarLoc());
+    return Result;
+  }
+
+  if (getDerived().AlwaysRebuild() ||
+      PointeeType != TL.getPointeeLoc().getType()) {
+    Result = getDerived().RebuildPointerType(PointeeType, TL.getSigilLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+               
+  // Objective-C ARC can add lifetime qualifiers to the type that we're
+  // pointing to.
+  TLB.TypeWasModifiedSafely(Result->getPointeeType());
+  
+  PointerTypeLoc NewT = TLB.push<PointerTypeLoc>(Result);
+  NewT.setSigilLoc(TL.getSigilLoc());
+  return Result;  
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformBlockPointerType(TypeLocBuilder &TLB,
+                                                  BlockPointerTypeLoc TL) {
+  QualType PointeeType
+    = getDerived().TransformType(TLB, TL.getPointeeLoc());  
+  if (PointeeType.isNull())                                 
+    return QualType();                                      
+  
+  QualType Result = TL.getType();                           
+  if (getDerived().AlwaysRebuild() ||                       
+      PointeeType != TL.getPointeeLoc().getType()) {        
+    Result = getDerived().RebuildBlockPointerType(PointeeType, 
+                                                  TL.getSigilLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  BlockPointerTypeLoc NewT = TLB.push<BlockPointerTypeLoc>(Result);
+  NewT.setSigilLoc(TL.getSigilLoc());
+  return Result;
+}
+
+/// Transforms a reference type.  Note that somewhat paradoxically we
+/// don't care whether the type itself is an l-value type or an r-value
+/// type;  we only care if the type was *written* as an l-value type
+/// or an r-value type.
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformReferenceType(TypeLocBuilder &TLB,
+                                               ReferenceTypeLoc TL) {
+  const ReferenceType *T = TL.getTypePtr();
+
+  // Note that this works with the pointee-as-written.
+  QualType PointeeType = getDerived().TransformType(TLB, TL.getPointeeLoc());
+  if (PointeeType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      PointeeType != T->getPointeeTypeAsWritten()) {
+    Result = getDerived().RebuildReferenceType(PointeeType,
+                                               T->isSpelledAsLValue(),
+                                               TL.getSigilLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  // Objective-C ARC can add lifetime qualifiers to the type that we're
+  // referring to.
+  TLB.TypeWasModifiedSafely(
+                     Result->getAs<ReferenceType>()->getPointeeTypeAsWritten());
+
+  // r-value references can be rebuilt as l-value references.
+  ReferenceTypeLoc NewTL;
+  if (isa<LValueReferenceType>(Result))
+    NewTL = TLB.push<LValueReferenceTypeLoc>(Result);
+  else
+    NewTL = TLB.push<RValueReferenceTypeLoc>(Result);
+  NewTL.setSigilLoc(TL.getSigilLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformLValueReferenceType(TypeLocBuilder &TLB,
+                                                 LValueReferenceTypeLoc TL) {
+  return TransformReferenceType(TLB, TL);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformRValueReferenceType(TypeLocBuilder &TLB,
+                                                 RValueReferenceTypeLoc TL) {
+  return TransformReferenceType(TLB, TL);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformMemberPointerType(TypeLocBuilder &TLB,
+                                                   MemberPointerTypeLoc TL) {
+  QualType PointeeType = getDerived().TransformType(TLB, TL.getPointeeLoc());
+  if (PointeeType.isNull())
+    return QualType();
+
+  TypeSourceInfo* OldClsTInfo = TL.getClassTInfo();
+  TypeSourceInfo* NewClsTInfo = 0;
+  if (OldClsTInfo) {
+    NewClsTInfo = getDerived().TransformType(OldClsTInfo);
+    if (!NewClsTInfo)
+      return QualType();
+  }
+
+  const MemberPointerType *T = TL.getTypePtr();
+  QualType OldClsType = QualType(T->getClass(), 0);
+  QualType NewClsType;
+  if (NewClsTInfo)
+    NewClsType = NewClsTInfo->getType();
+  else {
+    NewClsType = getDerived().TransformType(OldClsType);
+    if (NewClsType.isNull())
+      return QualType();
+  }
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      PointeeType != T->getPointeeType() ||
+      NewClsType != OldClsType) {
+    Result = getDerived().RebuildMemberPointerType(PointeeType, NewClsType,
+                                                   TL.getStarLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  MemberPointerTypeLoc NewTL = TLB.push<MemberPointerTypeLoc>(Result);
+  NewTL.setSigilLoc(TL.getSigilLoc());
+  NewTL.setClassTInfo(NewClsTInfo);
+
+  return Result;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformConstantArrayType(TypeLocBuilder &TLB,
+                                                   ConstantArrayTypeLoc TL) {
+  const ConstantArrayType *T = TL.getTypePtr();
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
+  if (ElementType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ElementType != T->getElementType()) {
+    Result = getDerived().RebuildConstantArrayType(ElementType,
+                                                   T->getSizeModifier(),
+                                                   T->getSize(),
+                                             T->getIndexTypeCVRQualifiers(),
+                                                   TL.getBracketsRange());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  // We might have either a ConstantArrayType or a VariableArrayType now:
+  // a ConstantArrayType is allowed to have an element type which is a
+  // VariableArrayType if the type is dependent.  Fortunately, all array
+  // types have the same location layout.
+  ArrayTypeLoc NewTL = TLB.push<ArrayTypeLoc>(Result);
+  NewTL.setLBracketLoc(TL.getLBracketLoc());
+  NewTL.setRBracketLoc(TL.getRBracketLoc());
+
+  Expr *Size = TL.getSizeExpr();
+  if (Size) {
+    EnterExpressionEvaluationContext Unevaluated(SemaRef,
+                                                 Sema::ConstantEvaluated);
+    Size = getDerived().TransformExpr(Size).template takeAs<Expr>();
+    Size = SemaRef.ActOnConstantExpression(Size).take();
+  }
+  NewTL.setSizeExpr(Size);
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformIncompleteArrayType(
+                                              TypeLocBuilder &TLB,
+                                              IncompleteArrayTypeLoc TL) {
+  const IncompleteArrayType *T = TL.getTypePtr();
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
+  if (ElementType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ElementType != T->getElementType()) {
+    Result = getDerived().RebuildIncompleteArrayType(ElementType,
+                                                     T->getSizeModifier(),
+                                           T->getIndexTypeCVRQualifiers(),
+                                                     TL.getBracketsRange());
+    if (Result.isNull())
+      return QualType();
+  }
+  
+  IncompleteArrayTypeLoc NewTL = TLB.push<IncompleteArrayTypeLoc>(Result);
+  NewTL.setLBracketLoc(TL.getLBracketLoc());
+  NewTL.setRBracketLoc(TL.getRBracketLoc());
+  NewTL.setSizeExpr(0);
+
+  return Result;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformVariableArrayType(TypeLocBuilder &TLB,
+                                                   VariableArrayTypeLoc TL) {
+  const VariableArrayType *T = TL.getTypePtr();
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
+  if (ElementType.isNull())
+    return QualType();
+
+  ExprResult SizeResult
+    = getDerived().TransformExpr(T->getSizeExpr());
+  if (SizeResult.isInvalid())
+    return QualType();
+
+  Expr *Size = SizeResult.take();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ElementType != T->getElementType() ||
+      Size != T->getSizeExpr()) {
+    Result = getDerived().RebuildVariableArrayType(ElementType,
+                                                   T->getSizeModifier(),
+                                                   Size,
+                                             T->getIndexTypeCVRQualifiers(),
+                                                   TL.getBracketsRange());
+    if (Result.isNull())
+      return QualType();
+  }
+  
+  VariableArrayTypeLoc NewTL = TLB.push<VariableArrayTypeLoc>(Result);
+  NewTL.setLBracketLoc(TL.getLBracketLoc());
+  NewTL.setRBracketLoc(TL.getRBracketLoc());
+  NewTL.setSizeExpr(Size);
+
+  return Result;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformDependentSizedArrayType(TypeLocBuilder &TLB,
+                                             DependentSizedArrayTypeLoc TL) {
+  const DependentSizedArrayType *T = TL.getTypePtr();
+  QualType ElementType = getDerived().TransformType(TLB, TL.getElementLoc());
+  if (ElementType.isNull())
+    return QualType();
+
+  // Array bounds are constant expressions.
+  EnterExpressionEvaluationContext Unevaluated(SemaRef,
+                                               Sema::ConstantEvaluated);
+
+  // Prefer the expression from the TypeLoc;  the other may have been uniqued.
+  Expr *origSize = TL.getSizeExpr();
+  if (!origSize) origSize = T->getSizeExpr();
+
+  ExprResult sizeResult
+    = getDerived().TransformExpr(origSize);
+  sizeResult = SemaRef.ActOnConstantExpression(sizeResult);
+  if (sizeResult.isInvalid())
+    return QualType();
+
+  Expr *size = sizeResult.get();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ElementType != T->getElementType() ||
+      size != origSize) {
+    Result = getDerived().RebuildDependentSizedArrayType(ElementType,
+                                                         T->getSizeModifier(),
+                                                         size,
+                                                T->getIndexTypeCVRQualifiers(),
+                                                        TL.getBracketsRange());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  // We might have any sort of array type now, but fortunately they
+  // all have the same location layout.
+  ArrayTypeLoc NewTL = TLB.push<ArrayTypeLoc>(Result);
+  NewTL.setLBracketLoc(TL.getLBracketLoc());
+  NewTL.setRBracketLoc(TL.getRBracketLoc());
+  NewTL.setSizeExpr(size);
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformDependentSizedExtVectorType(
+                                      TypeLocBuilder &TLB,
+                                      DependentSizedExtVectorTypeLoc TL) {
+  const DependentSizedExtVectorType *T = TL.getTypePtr();
+
+  // FIXME: ext vector locs should be nested
+  QualType ElementType = getDerived().TransformType(T->getElementType());
+  if (ElementType.isNull())
+    return QualType();
+
+  // Vector sizes are constant expressions.
+  EnterExpressionEvaluationContext Unevaluated(SemaRef,
+                                               Sema::ConstantEvaluated);
+
+  ExprResult Size = getDerived().TransformExpr(T->getSizeExpr());
+  Size = SemaRef.ActOnConstantExpression(Size);
+  if (Size.isInvalid())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ElementType != T->getElementType() ||
+      Size.get() != T->getSizeExpr()) {
+    Result = getDerived().RebuildDependentSizedExtVectorType(ElementType,
+                                                             Size.take(),
+                                                         T->getAttributeLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  // Result might be dependent or not.
+  if (isa<DependentSizedExtVectorType>(Result)) {
+    DependentSizedExtVectorTypeLoc NewTL
+      = TLB.push<DependentSizedExtVectorTypeLoc>(Result);
+    NewTL.setNameLoc(TL.getNameLoc());
+  } else {
+    ExtVectorTypeLoc NewTL = TLB.push<ExtVectorTypeLoc>(Result);
+    NewTL.setNameLoc(TL.getNameLoc());
+  }
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformVectorType(TypeLocBuilder &TLB,
+                                                     VectorTypeLoc TL) {
+  const VectorType *T = TL.getTypePtr();
+  QualType ElementType = getDerived().TransformType(T->getElementType());
+  if (ElementType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ElementType != T->getElementType()) {
+    Result = getDerived().RebuildVectorType(ElementType, T->getNumElements(),
+                                            T->getVectorKind());
+    if (Result.isNull())
+      return QualType();
+  }
+  
+  VectorTypeLoc NewTL = TLB.push<VectorTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformExtVectorType(TypeLocBuilder &TLB,
+                                                        ExtVectorTypeLoc TL) {
+  const VectorType *T = TL.getTypePtr();
+  QualType ElementType = getDerived().TransformType(T->getElementType());
+  if (ElementType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ElementType != T->getElementType()) {
+    Result = getDerived().RebuildExtVectorType(ElementType,
+                                               T->getNumElements(),
+                                               /*FIXME*/ SourceLocation());
+    if (Result.isNull())
+      return QualType();
+  }
+  
+  ExtVectorTypeLoc NewTL = TLB.push<ExtVectorTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+ParmVarDecl *
+TreeTransform<Derived>::TransformFunctionTypeParam(ParmVarDecl *OldParm,
+                                                   int indexAdjustment,
+                                         llvm::Optional<unsigned> NumExpansions,
+                                                   bool ExpectParameterPack) {
+  TypeSourceInfo *OldDI = OldParm->getTypeSourceInfo();
+  TypeSourceInfo *NewDI = 0;
+  
+  if (NumExpansions && isa<PackExpansionType>(OldDI->getType())) {
+    // If we're substituting into a pack expansion type and we know the 
+    // length we want to expand to, just substitute for the pattern.
+    TypeLoc OldTL = OldDI->getTypeLoc();
+    PackExpansionTypeLoc OldExpansionTL = cast<PackExpansionTypeLoc>(OldTL);
+    
+    TypeLocBuilder TLB;
+    TypeLoc NewTL = OldDI->getTypeLoc();
+    TLB.reserve(NewTL.getFullDataSize());
+    
+    QualType Result = getDerived().TransformType(TLB, 
+                                               OldExpansionTL.getPatternLoc());
+    if (Result.isNull())
+      return 0;
+   
+    Result = RebuildPackExpansionType(Result, 
+                                OldExpansionTL.getPatternLoc().getSourceRange(), 
+                                      OldExpansionTL.getEllipsisLoc(),
+                                      NumExpansions);
+    if (Result.isNull())
+      return 0;
+    
+    PackExpansionTypeLoc NewExpansionTL
+      = TLB.push<PackExpansionTypeLoc>(Result);
+    NewExpansionTL.setEllipsisLoc(OldExpansionTL.getEllipsisLoc());
+    NewDI = TLB.getTypeSourceInfo(SemaRef.Context, Result);
+  } else
+    NewDI = getDerived().TransformType(OldDI);
+  if (!NewDI)
+    return 0;
+
+  if (NewDI == OldDI && indexAdjustment == 0)
+    return OldParm;
+
+  ParmVarDecl *newParm = ParmVarDecl::Create(SemaRef.Context,
+                                             OldParm->getDeclContext(),
+                                             OldParm->getInnerLocStart(),
+                                             OldParm->getLocation(),
+                                             OldParm->getIdentifier(),
+                                             NewDI->getType(),
+                                             NewDI,
+                                             OldParm->getStorageClass(),
+                                             OldParm->getStorageClassAsWritten(),
+                                             /* DefArg */ NULL);
+  newParm->setScopeInfo(OldParm->getFunctionScopeDepth(),
+                        OldParm->getFunctionScopeIndex() + indexAdjustment);
+  return newParm;
+}
+
+template<typename Derived>
+bool TreeTransform<Derived>::
+  TransformFunctionTypeParams(SourceLocation Loc,
+                              ParmVarDecl **Params, unsigned NumParams,
+                              const QualType *ParamTypes,
+                              SmallVectorImpl<QualType> &OutParamTypes,
+                              SmallVectorImpl<ParmVarDecl*> *PVars) {
+  int indexAdjustment = 0;
+
+  for (unsigned i = 0; i != NumParams; ++i) {
+    if (ParmVarDecl *OldParm = Params[i]) {
+      assert(OldParm->getFunctionScopeIndex() == i);
+
+      llvm::Optional<unsigned> NumExpansions;
+      ParmVarDecl *NewParm = 0;
+      if (OldParm->isParameterPack()) {
+        // We have a function parameter pack that may need to be expanded.
+        SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+
+        // Find the parameter packs that could be expanded.
+        TypeLoc TL = OldParm->getTypeSourceInfo()->getTypeLoc();
+        PackExpansionTypeLoc ExpansionTL = cast<PackExpansionTypeLoc>(TL);
+        TypeLoc Pattern = ExpansionTL.getPatternLoc();
+        SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);
+        assert(Unexpanded.size() > 0 && "Could not find parameter packs!");
+
+        // Determine whether we should expand the parameter packs.
+        bool ShouldExpand = false;
+        bool RetainExpansion = false;
+        llvm::Optional<unsigned> OrigNumExpansions
+          = ExpansionTL.getTypePtr()->getNumExpansions();
+        NumExpansions = OrigNumExpansions;
+        if (getDerived().TryExpandParameterPacks(ExpansionTL.getEllipsisLoc(),
+                                                 Pattern.getSourceRange(),
+                                                 Unexpanded, 
+                                                 ShouldExpand, 
+                                                 RetainExpansion,
+                                                 NumExpansions)) {
+          return true;
+        }
+        
+        if (ShouldExpand) {
+          // Expand the function parameter pack into multiple, separate
+          // parameters.
+          getDerived().ExpandingFunctionParameterPack(OldParm);
+          for (unsigned I = 0; I != *NumExpansions; ++I) {
+            Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), I);
+            ParmVarDecl *NewParm 
+              = getDerived().TransformFunctionTypeParam(OldParm,
+                                                        indexAdjustment++,
+                                                        OrigNumExpansions,
+                                                /*ExpectParameterPack=*/false);
+            if (!NewParm)
+              return true;
+            
+            OutParamTypes.push_back(NewParm->getType());
+            if (PVars)
+              PVars->push_back(NewParm);
+          }
+
+          // If we're supposed to retain a pack expansion, do so by temporarily
+          // forgetting the partially-substituted parameter pack.
+          if (RetainExpansion) {
+            ForgetPartiallySubstitutedPackRAII Forget(getDerived());
+            ParmVarDecl *NewParm 
+              = getDerived().TransformFunctionTypeParam(OldParm,
+                                                        indexAdjustment++,
+                                                        OrigNumExpansions,
+                                                /*ExpectParameterPack=*/false);
+            if (!NewParm)
+              return true;
+            
+            OutParamTypes.push_back(NewParm->getType());
+            if (PVars)
+              PVars->push_back(NewParm);
+          }
+
+          // The next parameter should have the same adjustment as the
+          // last thing we pushed, but we post-incremented indexAdjustment
+          // on every push.  Also, if we push nothing, the adjustment should
+          // go down by one.
+          indexAdjustment--;
+
+          // We're done with the pack expansion.
+          continue;
+        }
+        
+        // We'll substitute the parameter now without expanding the pack 
+        // expansion.
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), -1);
+        NewParm = getDerived().TransformFunctionTypeParam(OldParm,
+                                                          indexAdjustment,
+                                                          NumExpansions,
+                                                  /*ExpectParameterPack=*/true);
+      } else {
+        NewParm = getDerived().TransformFunctionTypeParam(OldParm,
+                                                          indexAdjustment,
+                                                          llvm::Optional<unsigned>(),
+                                                /*ExpectParameterPack=*/false);
+      }
+
+      if (!NewParm)
+        return true;
+      
+      OutParamTypes.push_back(NewParm->getType());
+      if (PVars)
+        PVars->push_back(NewParm);
+      continue;
+    }
+
+    // Deal with the possibility that we don't have a parameter
+    // declaration for this parameter.
+    QualType OldType = ParamTypes[i];
+    bool IsPackExpansion = false;
+    llvm::Optional<unsigned> NumExpansions;
+    QualType NewType;
+    if (const PackExpansionType *Expansion 
+                                       = dyn_cast<PackExpansionType>(OldType)) {
+      // We have a function parameter pack that may need to be expanded.
+      QualType Pattern = Expansion->getPattern();
+      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      getSema().collectUnexpandedParameterPacks(Pattern, Unexpanded);
+      
+      // Determine whether we should expand the parameter packs.
+      bool ShouldExpand = false;
+      bool RetainExpansion = false;
+      if (getDerived().TryExpandParameterPacks(Loc, SourceRange(),
+                                               Unexpanded, 
+                                               ShouldExpand, 
+                                               RetainExpansion,
+                                               NumExpansions)) {
+        return true;
+      }
+      
+      if (ShouldExpand) {
+        // Expand the function parameter pack into multiple, separate 
+        // parameters.
+        for (unsigned I = 0; I != *NumExpansions; ++I) {
+          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), I);
+          QualType NewType = getDerived().TransformType(Pattern);
+          if (NewType.isNull())
+            return true;
+
+          OutParamTypes.push_back(NewType);
+          if (PVars)
+            PVars->push_back(0);
+        }
+        
+        // We're done with the pack expansion.
+        continue;
+      }
+      
+      // If we're supposed to retain a pack expansion, do so by temporarily
+      // forgetting the partially-substituted parameter pack.
+      if (RetainExpansion) {
+        ForgetPartiallySubstitutedPackRAII Forget(getDerived());
+        QualType NewType = getDerived().TransformType(Pattern);
+        if (NewType.isNull())
+          return true;
+        
+        OutParamTypes.push_back(NewType);
+        if (PVars)
+          PVars->push_back(0);
+      }
+
+      // We'll substitute the parameter now without expanding the pack 
+      // expansion.
+      OldType = Expansion->getPattern();
+      IsPackExpansion = true;
+      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), -1);
+      NewType = getDerived().TransformType(OldType);
+    } else {
+      NewType = getDerived().TransformType(OldType);
+    }
+    
+    if (NewType.isNull())
+      return true;
+
+    if (IsPackExpansion)
+      NewType = getSema().Context.getPackExpansionType(NewType,
+                                                       NumExpansions);
+      
+    OutParamTypes.push_back(NewType);
+    if (PVars)
+      PVars->push_back(0);
+  }
+
+#ifndef NDEBUG
+  if (PVars) {
+    for (unsigned i = 0, e = PVars->size(); i != e; ++i)
+      if (ParmVarDecl *parm = (*PVars)[i])
+        assert(parm->getFunctionScopeIndex() == i);
+  }
+#endif
+
+  return false;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformFunctionProtoType(TypeLocBuilder &TLB,
+                                                   FunctionProtoTypeLoc TL) {
+  return getDerived().TransformFunctionProtoType(TLB, TL, 0, 0);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformFunctionProtoType(TypeLocBuilder &TLB,
+                                                   FunctionProtoTypeLoc TL,
+                                                   CXXRecordDecl *ThisContext,
+                                                   unsigned ThisTypeQuals) {
+  // Transform the parameters and return type.
+  //
+  // We are required to instantiate the params and return type in source order.
+  // When the function has a trailing return type, we instantiate the
+  // parameters before the return type,  since the return type can then refer
+  // to the parameters themselves (via decltype, sizeof, etc.).
+  //
+  SmallVector<QualType, 4> ParamTypes;
+  SmallVector<ParmVarDecl*, 4> ParamDecls;
+  const FunctionProtoType *T = TL.getTypePtr();
+
+  QualType ResultType;
+
+  if (TL.getTrailingReturn()) {
+    if (getDerived().TransformFunctionTypeParams(TL.getBeginLoc(), 
+                                                 TL.getParmArray(),
+                                                 TL.getNumArgs(),
+                                             TL.getTypePtr()->arg_type_begin(),                                                
+                                                 ParamTypes, &ParamDecls))
+      return QualType();
+
+    {
+      // C++11 [expr.prim.general]p3:
+      //   If a declaration declares a member function or member function 
+      //   template of a class X, the expression this is a prvalue of type 
+      //   "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
+      //   and the end of the function-definition, member-declarator, or 
+      //   declarator.
+      Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, ThisTypeQuals);
+      
+      ResultType = getDerived().TransformType(TLB, TL.getResultLoc());
+      if (ResultType.isNull())
+        return QualType();
+    }
+  }
+  else {
+    ResultType = getDerived().TransformType(TLB, TL.getResultLoc());
+    if (ResultType.isNull())
+      return QualType();
+
+    if (getDerived().TransformFunctionTypeParams(TL.getBeginLoc(), 
+                                                 TL.getParmArray(),
+                                                 TL.getNumArgs(),
+                                             TL.getTypePtr()->arg_type_begin(),                                                
+                                                 ParamTypes, &ParamDecls))
+      return QualType();
+  }
+
+  // FIXME: Need to transform the exception-specification too.
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ResultType != T->getResultType() ||
+      T->getNumArgs() != ParamTypes.size() ||
+      !std::equal(T->arg_type_begin(), T->arg_type_end(), ParamTypes.begin())) {
+    Result = getDerived().RebuildFunctionProtoType(ResultType,
+                                                   ParamTypes.data(),
+                                                   ParamTypes.size(),
+                                                   T->isVariadic(),
+                                                   T->hasTrailingReturn(),
+                                                   T->getTypeQuals(),
+                                                   T->getRefQualifier(),
+                                                   T->getExtInfo());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
+  NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
+  NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
+  NewTL.setTrailingReturn(TL.getTrailingReturn());
+  for (unsigned i = 0, e = NewTL.getNumArgs(); i != e; ++i)
+    NewTL.setArg(i, ParamDecls[i]);
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformFunctionNoProtoType(
+                                                 TypeLocBuilder &TLB,
+                                                 FunctionNoProtoTypeLoc TL) {
+  const FunctionNoProtoType *T = TL.getTypePtr();
+  QualType ResultType = getDerived().TransformType(TLB, TL.getResultLoc());
+  if (ResultType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ResultType != T->getResultType())
+    Result = getDerived().RebuildFunctionNoProtoType(ResultType);
+
+  FunctionNoProtoTypeLoc NewTL = TLB.push<FunctionNoProtoTypeLoc>(Result);
+  NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
+  NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
+  NewTL.setTrailingReturn(false);
+
+  return Result;
+}
+
+template<typename Derived> QualType
+TreeTransform<Derived>::TransformUnresolvedUsingType(TypeLocBuilder &TLB,
+                                                 UnresolvedUsingTypeLoc TL) {
+  const UnresolvedUsingType *T = TL.getTypePtr();
+  Decl *D = getDerived().TransformDecl(TL.getNameLoc(), T->getDecl());
+  if (!D)
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() || D != T->getDecl()) {
+    Result = getDerived().RebuildUnresolvedUsingType(D);
+    if (Result.isNull())
+      return QualType();
+  }
+
+  // We might get an arbitrary type spec type back.  We should at
+  // least always get a type spec type, though.
+  TypeSpecTypeLoc NewTL = TLB.pushTypeSpec(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformTypedefType(TypeLocBuilder &TLB,
+                                                      TypedefTypeLoc TL) {
+  const TypedefType *T = TL.getTypePtr();
+  TypedefNameDecl *Typedef
+    = cast_or_null<TypedefNameDecl>(getDerived().TransformDecl(TL.getNameLoc(),
+                                                               T->getDecl()));
+  if (!Typedef)
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      Typedef != T->getDecl()) {
+    Result = getDerived().RebuildTypedefType(Typedef);
+    if (Result.isNull())
+      return QualType();
+  }
+
+  TypedefTypeLoc NewTL = TLB.push<TypedefTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformTypeOfExprType(TypeLocBuilder &TLB,
+                                                      TypeOfExprTypeLoc TL) {
+  // typeof expressions are not potentially evaluated contexts
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+
+  ExprResult E = getDerived().TransformExpr(TL.getUnderlyingExpr());
+  if (E.isInvalid())
+    return QualType();
+
+  E = SemaRef.HandleExprEvaluationContextForTypeof(E.get());
+  if (E.isInvalid())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      E.get() != TL.getUnderlyingExpr()) {
+    Result = getDerived().RebuildTypeOfExprType(E.get(), TL.getTypeofLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+  else E.take();
+
+  TypeOfExprTypeLoc NewTL = TLB.push<TypeOfExprTypeLoc>(Result);
+  NewTL.setTypeofLoc(TL.getTypeofLoc());
+  NewTL.setLParenLoc(TL.getLParenLoc());
+  NewTL.setRParenLoc(TL.getRParenLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformTypeOfType(TypeLocBuilder &TLB,
+                                                     TypeOfTypeLoc TL) {
+  TypeSourceInfo* Old_Under_TI = TL.getUnderlyingTInfo();
+  TypeSourceInfo* New_Under_TI = getDerived().TransformType(Old_Under_TI);
+  if (!New_Under_TI)
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() || New_Under_TI != Old_Under_TI) {
+    Result = getDerived().RebuildTypeOfType(New_Under_TI->getType());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  TypeOfTypeLoc NewTL = TLB.push<TypeOfTypeLoc>(Result);
+  NewTL.setTypeofLoc(TL.getTypeofLoc());
+  NewTL.setLParenLoc(TL.getLParenLoc());
+  NewTL.setRParenLoc(TL.getRParenLoc());
+  NewTL.setUnderlyingTInfo(New_Under_TI);
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformDecltypeType(TypeLocBuilder &TLB,
+                                                       DecltypeTypeLoc TL) {
+  const DecltypeType *T = TL.getTypePtr();
+
+  // decltype expressions are not potentially evaluated contexts
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated, 0,
+                                               /*IsDecltype=*/ true);
+
+  ExprResult E = getDerived().TransformExpr(T->getUnderlyingExpr());
+  if (E.isInvalid())
+    return QualType();
+
+  E = getSema().ActOnDecltypeExpression(E.take());
+  if (E.isInvalid())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      E.get() != T->getUnderlyingExpr()) {
+    Result = getDerived().RebuildDecltypeType(E.get(), TL.getNameLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+  else E.take();
+
+  DecltypeTypeLoc NewTL = TLB.push<DecltypeTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformUnaryTransformType(
+                                                            TypeLocBuilder &TLB,
+                                                     UnaryTransformTypeLoc TL) {
+  QualType Result = TL.getType();
+  if (Result->isDependentType()) {
+    const UnaryTransformType *T = TL.getTypePtr();
+    QualType NewBase =
+      getDerived().TransformType(TL.getUnderlyingTInfo())->getType();
+    Result = getDerived().RebuildUnaryTransformType(NewBase,
+                                                    T->getUTTKind(),
+                                                    TL.getKWLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  UnaryTransformTypeLoc NewTL = TLB.push<UnaryTransformTypeLoc>(Result);
+  NewTL.setKWLoc(TL.getKWLoc());
+  NewTL.setParensRange(TL.getParensRange());
+  NewTL.setUnderlyingTInfo(TL.getUnderlyingTInfo());
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformAutoType(TypeLocBuilder &TLB,
+                                                   AutoTypeLoc TL) {
+  const AutoType *T = TL.getTypePtr();
+  QualType OldDeduced = T->getDeducedType();
+  QualType NewDeduced;
+  if (!OldDeduced.isNull()) {
+    NewDeduced = getDerived().TransformType(OldDeduced);
+    if (NewDeduced.isNull())
+      return QualType();
+  }
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() || NewDeduced != OldDeduced) {
+    Result = getDerived().RebuildAutoType(NewDeduced);
+    if (Result.isNull())
+      return QualType();
+  }
+
+  AutoTypeLoc NewTL = TLB.push<AutoTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformRecordType(TypeLocBuilder &TLB,
+                                                     RecordTypeLoc TL) {
+  const RecordType *T = TL.getTypePtr();
+  RecordDecl *Record
+    = cast_or_null<RecordDecl>(getDerived().TransformDecl(TL.getNameLoc(),
+                                                          T->getDecl()));
+  if (!Record)
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      Record != T->getDecl()) {
+    Result = getDerived().RebuildRecordType(Record);
+    if (Result.isNull())
+      return QualType();
+  }
+
+  RecordTypeLoc NewTL = TLB.push<RecordTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformEnumType(TypeLocBuilder &TLB,
+                                                   EnumTypeLoc TL) {
+  const EnumType *T = TL.getTypePtr();
+  EnumDecl *Enum
+    = cast_or_null<EnumDecl>(getDerived().TransformDecl(TL.getNameLoc(),
+                                                        T->getDecl()));
+  if (!Enum)
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      Enum != T->getDecl()) {
+    Result = getDerived().RebuildEnumType(Enum);
+    if (Result.isNull())
+      return QualType();
+  }
+
+  EnumTypeLoc NewTL = TLB.push<EnumTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformInjectedClassNameType(
+                                         TypeLocBuilder &TLB,
+                                         InjectedClassNameTypeLoc TL) {
+  Decl *D = getDerived().TransformDecl(TL.getNameLoc(),
+                                       TL.getTypePtr()->getDecl());
+  if (!D) return QualType();
+
+  QualType T = SemaRef.Context.getTypeDeclType(cast<TypeDecl>(D));
+  TLB.pushTypeSpec(T).setNameLoc(TL.getNameLoc());
+  return T;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformTemplateTypeParmType(
+                                                TypeLocBuilder &TLB,
+                                                TemplateTypeParmTypeLoc TL) {
+  return TransformTypeSpecType(TLB, TL);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformSubstTemplateTypeParmType(
+                                         TypeLocBuilder &TLB,
+                                         SubstTemplateTypeParmTypeLoc TL) {
+  const SubstTemplateTypeParmType *T = TL.getTypePtr();
+  
+  // Substitute into the replacement type, which itself might involve something
+  // that needs to be transformed. This only tends to occur with default
+  // template arguments of template template parameters.
+  TemporaryBase Rebase(*this, TL.getNameLoc(), DeclarationName());
+  QualType Replacement = getDerived().TransformType(T->getReplacementType());
+  if (Replacement.isNull())
+    return QualType();
+  
+  // Always canonicalize the replacement type.
+  Replacement = SemaRef.Context.getCanonicalType(Replacement);
+  QualType Result
+    = SemaRef.Context.getSubstTemplateTypeParmType(T->getReplacedParameter(), 
+                                                   Replacement);
+  
+  // Propagate type-source information.
+  SubstTemplateTypeParmTypeLoc NewTL
+    = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
+  NewTL.setNameLoc(TL.getNameLoc());
+  return Result;
+
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformSubstTemplateTypeParmPackType(
+                                          TypeLocBuilder &TLB,
+                                          SubstTemplateTypeParmPackTypeLoc TL) {
+  return TransformTypeSpecType(TLB, TL);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformTemplateSpecializationType(
+                                                        TypeLocBuilder &TLB,
+                                           TemplateSpecializationTypeLoc TL) {
+  const TemplateSpecializationType *T = TL.getTypePtr();
+
+  // The nested-name-specifier never matters in a TemplateSpecializationType,
+  // because we can't have a dependent nested-name-specifier anyway.
+  CXXScopeSpec SS;
+  TemplateName Template
+    = getDerived().TransformTemplateName(SS, T->getTemplateName(),
+                                         TL.getTemplateNameLoc());
+  if (Template.isNull())
+    return QualType();
+
+  return getDerived().TransformTemplateSpecializationType(TLB, TL, Template);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformAtomicType(TypeLocBuilder &TLB,
+                                                     AtomicTypeLoc TL) {
+  QualType ValueType = getDerived().TransformType(TLB, TL.getValueLoc());
+  if (ValueType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      ValueType != TL.getValueLoc().getType()) {
+    Result = getDerived().RebuildAtomicType(ValueType, TL.getKWLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  AtomicTypeLoc NewTL = TLB.push<AtomicTypeLoc>(Result);
+  NewTL.setKWLoc(TL.getKWLoc());
+  NewTL.setLParenLoc(TL.getLParenLoc());
+  NewTL.setRParenLoc(TL.getRParenLoc());
+
+  return Result;
+}
+
+namespace {
+  /// \brief Simple iterator that traverses the template arguments in a 
+  /// container that provides a \c getArgLoc() member function.
+  ///
+  /// This iterator is intended to be used with the iterator form of
+  /// \c TreeTransform<Derived>::TransformTemplateArguments().
+  template<typename ArgLocContainer>
+  class TemplateArgumentLocContainerIterator {
+    ArgLocContainer *Container;
+    unsigned Index;
+    
+  public:
+    typedef TemplateArgumentLoc value_type;
+    typedef TemplateArgumentLoc reference;
+    typedef int difference_type;
+    typedef std::input_iterator_tag iterator_category;
+    
+    class pointer {
+      TemplateArgumentLoc Arg;
+      
+    public:
+      explicit pointer(TemplateArgumentLoc Arg) : Arg(Arg) { }
+      
+      const TemplateArgumentLoc *operator->() const {
+        return &Arg;
+      }
+    };
+    
+    
+    TemplateArgumentLocContainerIterator() {}
+    
+    TemplateArgumentLocContainerIterator(ArgLocContainer &Container,
+                                 unsigned Index)
+      : Container(&Container), Index(Index) { }
+    
+    TemplateArgumentLocContainerIterator &operator++() {
+      ++Index;
+      return *this;
+    }
+    
+    TemplateArgumentLocContainerIterator operator++(int) {
+      TemplateArgumentLocContainerIterator Old(*this);
+      ++(*this);
+      return Old;
+    }
+    
+    TemplateArgumentLoc operator*() const {
+      return Container->getArgLoc(Index);
+    }
+    
+    pointer operator->() const {
+      return pointer(Container->getArgLoc(Index));
+    }
+    
+    friend bool operator==(const TemplateArgumentLocContainerIterator &X,
+                           const TemplateArgumentLocContainerIterator &Y) {
+      return X.Container == Y.Container && X.Index == Y.Index;
+    }
+    
+    friend bool operator!=(const TemplateArgumentLocContainerIterator &X,
+                           const TemplateArgumentLocContainerIterator &Y) {
+      return !(X == Y);
+    }
+  };
+}
+  
+  
+template <typename Derived>
+QualType TreeTransform<Derived>::TransformTemplateSpecializationType(
+                                                        TypeLocBuilder &TLB,
+                                           TemplateSpecializationTypeLoc TL,
+                                                      TemplateName Template) {
+  TemplateArgumentListInfo NewTemplateArgs;
+  NewTemplateArgs.setLAngleLoc(TL.getLAngleLoc());
+  NewTemplateArgs.setRAngleLoc(TL.getRAngleLoc());
+  typedef TemplateArgumentLocContainerIterator<TemplateSpecializationTypeLoc>
+    ArgIterator;
+  if (getDerived().TransformTemplateArguments(ArgIterator(TL, 0), 
+                                              ArgIterator(TL, TL.getNumArgs()),
+                                              NewTemplateArgs))
+    return QualType();
+
+  // FIXME: maybe don't rebuild if all the template arguments are the same.
+
+  QualType Result =
+    getDerived().RebuildTemplateSpecializationType(Template,
+                                                   TL.getTemplateNameLoc(),
+                                                   NewTemplateArgs);
+
+  if (!Result.isNull()) {
+    // Specializations of template template parameters are represented as
+    // TemplateSpecializationTypes, and substitution of type alias templates
+    // within a dependent context can transform them into
+    // DependentTemplateSpecializationTypes.
+    if (isa<DependentTemplateSpecializationType>(Result)) {
+      DependentTemplateSpecializationTypeLoc NewTL
+        = TLB.push<DependentTemplateSpecializationTypeLoc>(Result);
+      NewTL.setElaboratedKeywordLoc(SourceLocation());
+      NewTL.setQualifierLoc(NestedNameSpecifierLoc());
+      NewTL.setTemplateKeywordLoc(TL.getTemplateKeywordLoc());
+      NewTL.setTemplateNameLoc(TL.getTemplateNameLoc());
+      NewTL.setLAngleLoc(TL.getLAngleLoc());
+      NewTL.setRAngleLoc(TL.getRAngleLoc());
+      for (unsigned i = 0, e = NewTemplateArgs.size(); i != e; ++i)
+        NewTL.setArgLocInfo(i, NewTemplateArgs[i].getLocInfo());
+      return Result;
+    }
+
+    TemplateSpecializationTypeLoc NewTL
+      = TLB.push<TemplateSpecializationTypeLoc>(Result);
+    NewTL.setTemplateKeywordLoc(TL.getTemplateKeywordLoc());
+    NewTL.setTemplateNameLoc(TL.getTemplateNameLoc());
+    NewTL.setLAngleLoc(TL.getLAngleLoc());
+    NewTL.setRAngleLoc(TL.getRAngleLoc());
+    for (unsigned i = 0, e = NewTemplateArgs.size(); i != e; ++i)
+      NewTL.setArgLocInfo(i, NewTemplateArgs[i].getLocInfo());
+  }
+
+  return Result;
+}
+
+template <typename Derived>
+QualType TreeTransform<Derived>::TransformDependentTemplateSpecializationType(
+                                     TypeLocBuilder &TLB,
+                                     DependentTemplateSpecializationTypeLoc TL,
+                                     TemplateName Template,
+                                     CXXScopeSpec &SS) {
+  TemplateArgumentListInfo NewTemplateArgs;
+  NewTemplateArgs.setLAngleLoc(TL.getLAngleLoc());
+  NewTemplateArgs.setRAngleLoc(TL.getRAngleLoc());
+  typedef TemplateArgumentLocContainerIterator<
+            DependentTemplateSpecializationTypeLoc> ArgIterator;
+  if (getDerived().TransformTemplateArguments(ArgIterator(TL, 0), 
+                                              ArgIterator(TL, TL.getNumArgs()),
+                                              NewTemplateArgs))
+    return QualType();
+  
+  // FIXME: maybe don't rebuild if all the template arguments are the same.
+  
+  if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
+    QualType Result
+      = getSema().Context.getDependentTemplateSpecializationType(
+                                                TL.getTypePtr()->getKeyword(),
+                                                         DTN->getQualifier(),
+                                                         DTN->getIdentifier(),
+                                                               NewTemplateArgs);
+   
+    DependentTemplateSpecializationTypeLoc NewTL
+      = TLB.push<DependentTemplateSpecializationTypeLoc>(Result);
+    NewTL.setElaboratedKeywordLoc(TL.getElaboratedKeywordLoc());
+    NewTL.setQualifierLoc(SS.getWithLocInContext(SemaRef.Context));
+    NewTL.setTemplateKeywordLoc(TL.getTemplateKeywordLoc());
+    NewTL.setTemplateNameLoc(TL.getTemplateNameLoc());
+    NewTL.setLAngleLoc(TL.getLAngleLoc());
+    NewTL.setRAngleLoc(TL.getRAngleLoc());
+    for (unsigned i = 0, e = NewTemplateArgs.size(); i != e; ++i)
+      NewTL.setArgLocInfo(i, NewTemplateArgs[i].getLocInfo());
+    return Result;
+  }
+      
+  QualType Result 
+    = getDerived().RebuildTemplateSpecializationType(Template,
+                                                     TL.getTemplateNameLoc(),
+                                                     NewTemplateArgs);
+  
+  if (!Result.isNull()) {
+    /// FIXME: Wrap this in an elaborated-type-specifier?
+    TemplateSpecializationTypeLoc NewTL
+      = TLB.push<TemplateSpecializationTypeLoc>(Result);
+    NewTL.setTemplateKeywordLoc(TL.getTemplateKeywordLoc());
+    NewTL.setTemplateNameLoc(TL.getTemplateNameLoc());
+    NewTL.setLAngleLoc(TL.getLAngleLoc());
+    NewTL.setRAngleLoc(TL.getRAngleLoc());
+    for (unsigned i = 0, e = NewTemplateArgs.size(); i != e; ++i)
+      NewTL.setArgLocInfo(i, NewTemplateArgs[i].getLocInfo());
+  }
+  
+  return Result;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformElaboratedType(TypeLocBuilder &TLB,
+                                                ElaboratedTypeLoc TL) {
+  const ElaboratedType *T = TL.getTypePtr();
+
+  NestedNameSpecifierLoc QualifierLoc;
+  // NOTE: the qualifier in an ElaboratedType is optional.
+  if (TL.getQualifierLoc()) {
+    QualifierLoc 
+      = getDerived().TransformNestedNameSpecifierLoc(TL.getQualifierLoc());
+    if (!QualifierLoc)
+      return QualType();
+  }
+
+  QualType NamedT = getDerived().TransformType(TLB, TL.getNamedTypeLoc());
+  if (NamedT.isNull())
+    return QualType();
+
+  // C++0x [dcl.type.elab]p2:
+  //   If the identifier resolves to a typedef-name or the simple-template-id
+  //   resolves to an alias template specialization, the
+  //   elaborated-type-specifier is ill-formed.
+  if (T->getKeyword() != ETK_None && T->getKeyword() != ETK_Typename) {
+    if (const TemplateSpecializationType *TST =
+          NamedT->getAs<TemplateSpecializationType>()) {
+      TemplateName Template = TST->getTemplateName();
+      if (TypeAliasTemplateDecl *TAT =
+          dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
+        SemaRef.Diag(TL.getNamedTypeLoc().getBeginLoc(),
+                     diag::err_tag_reference_non_tag) << 4;
+        SemaRef.Diag(TAT->getLocation(), diag::note_declared_at);
+      }
+    }
+  }
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      QualifierLoc != TL.getQualifierLoc() ||
+      NamedT != T->getNamedType()) {
+    Result = getDerived().RebuildElaboratedType(TL.getElaboratedKeywordLoc(),
+                                                T->getKeyword(), 
+                                                QualifierLoc, NamedT);
+    if (Result.isNull())
+      return QualType();
+  }
+
+  ElaboratedTypeLoc NewTL = TLB.push<ElaboratedTypeLoc>(Result);
+  NewTL.setElaboratedKeywordLoc(TL.getElaboratedKeywordLoc());
+  NewTL.setQualifierLoc(QualifierLoc);
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformAttributedType(
+                                                TypeLocBuilder &TLB,
+                                                AttributedTypeLoc TL) {
+  const AttributedType *oldType = TL.getTypePtr();
+  QualType modifiedType = getDerived().TransformType(TLB, TL.getModifiedLoc());
+  if (modifiedType.isNull())
+    return QualType();
+
+  QualType result = TL.getType();
+
+  // FIXME: dependent operand expressions?
+  if (getDerived().AlwaysRebuild() ||
+      modifiedType != oldType->getModifiedType()) {
+    // TODO: this is really lame; we should really be rebuilding the
+    // equivalent type from first principles.
+    QualType equivalentType
+      = getDerived().TransformType(oldType->getEquivalentType());
+    if (equivalentType.isNull())
+      return QualType();
+    result = SemaRef.Context.getAttributedType(oldType->getAttrKind(),
+                                               modifiedType,
+                                               equivalentType);
+  }
+
+  AttributedTypeLoc newTL = TLB.push<AttributedTypeLoc>(result);
+  newTL.setAttrNameLoc(TL.getAttrNameLoc());
+  if (TL.hasAttrOperand())
+    newTL.setAttrOperandParensRange(TL.getAttrOperandParensRange());
+  if (TL.hasAttrExprOperand())
+    newTL.setAttrExprOperand(TL.getAttrExprOperand());
+  else if (TL.hasAttrEnumOperand())
+    newTL.setAttrEnumOperandLoc(TL.getAttrEnumOperandLoc());
+
+  return result;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformParenType(TypeLocBuilder &TLB,
+                                           ParenTypeLoc TL) {
+  QualType Inner = getDerived().TransformType(TLB, TL.getInnerLoc());
+  if (Inner.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() ||
+      Inner != TL.getInnerLoc().getType()) {
+    Result = getDerived().RebuildParenType(Inner);
+    if (Result.isNull())
+      return QualType();
+  }
+
+  ParenTypeLoc NewTL = TLB.push<ParenTypeLoc>(Result);
+  NewTL.setLParenLoc(TL.getLParenLoc());
+  NewTL.setRParenLoc(TL.getRParenLoc());
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformDependentNameType(TypeLocBuilder &TLB,
+                                                      DependentNameTypeLoc TL) {
+  const DependentNameType *T = TL.getTypePtr();
+
+  NestedNameSpecifierLoc QualifierLoc
+    = getDerived().TransformNestedNameSpecifierLoc(TL.getQualifierLoc());
+  if (!QualifierLoc)
+    return QualType();
+
+  QualType Result
+    = getDerived().RebuildDependentNameType(T->getKeyword(),
+                                            TL.getElaboratedKeywordLoc(),
+                                            QualifierLoc,
+                                            T->getIdentifier(),
+                                            TL.getNameLoc());
+  if (Result.isNull())
+    return QualType();
+
+  if (const ElaboratedType* ElabT = Result->getAs<ElaboratedType>()) {
+    QualType NamedT = ElabT->getNamedType();
+    TLB.pushTypeSpec(NamedT).setNameLoc(TL.getNameLoc());
+
+    ElaboratedTypeLoc NewTL = TLB.push<ElaboratedTypeLoc>(Result);
+    NewTL.setElaboratedKeywordLoc(TL.getElaboratedKeywordLoc());
+    NewTL.setQualifierLoc(QualifierLoc);
+  } else {
+    DependentNameTypeLoc NewTL = TLB.push<DependentNameTypeLoc>(Result);
+    NewTL.setElaboratedKeywordLoc(TL.getElaboratedKeywordLoc());
+    NewTL.setQualifierLoc(QualifierLoc);
+    NewTL.setNameLoc(TL.getNameLoc());
+  }
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::
+          TransformDependentTemplateSpecializationType(TypeLocBuilder &TLB,
+                                 DependentTemplateSpecializationTypeLoc TL) {
+  NestedNameSpecifierLoc QualifierLoc;
+  if (TL.getQualifierLoc()) {
+    QualifierLoc
+      = getDerived().TransformNestedNameSpecifierLoc(TL.getQualifierLoc());
+    if (!QualifierLoc)
+      return QualType();
+  }
+            
+  return getDerived()
+           .TransformDependentTemplateSpecializationType(TLB, TL, QualifierLoc);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::
+TransformDependentTemplateSpecializationType(TypeLocBuilder &TLB,
+                                   DependentTemplateSpecializationTypeLoc TL,
+                                       NestedNameSpecifierLoc QualifierLoc) {
+  const DependentTemplateSpecializationType *T = TL.getTypePtr();
+  
+  TemplateArgumentListInfo NewTemplateArgs;
+  NewTemplateArgs.setLAngleLoc(TL.getLAngleLoc());
+  NewTemplateArgs.setRAngleLoc(TL.getRAngleLoc());
+  
+  typedef TemplateArgumentLocContainerIterator<
+  DependentTemplateSpecializationTypeLoc> ArgIterator;
+  if (getDerived().TransformTemplateArguments(ArgIterator(TL, 0),
+                                              ArgIterator(TL, TL.getNumArgs()),
+                                              NewTemplateArgs))
+    return QualType();
+  
+  QualType Result
+    = getDerived().RebuildDependentTemplateSpecializationType(T->getKeyword(),
+                                                              QualifierLoc,
+                                                            T->getIdentifier(),
+                                                       TL.getTemplateNameLoc(),
+                                                            NewTemplateArgs);
+  if (Result.isNull())
+    return QualType();
+  
+  if (const ElaboratedType *ElabT = dyn_cast<ElaboratedType>(Result)) {
+    QualType NamedT = ElabT->getNamedType();
+    
+    // Copy information relevant to the template specialization.
+    TemplateSpecializationTypeLoc NamedTL
+      = TLB.push<TemplateSpecializationTypeLoc>(NamedT);
+    NamedTL.setTemplateKeywordLoc(TL.getTemplateKeywordLoc());
+    NamedTL.setTemplateNameLoc(TL.getTemplateNameLoc());
+    NamedTL.setLAngleLoc(TL.getLAngleLoc());
+    NamedTL.setRAngleLoc(TL.getRAngleLoc());
+    for (unsigned I = 0, E = NewTemplateArgs.size(); I != E; ++I)
+      NamedTL.setArgLocInfo(I, NewTemplateArgs[I].getLocInfo());
+    
+    // Copy information relevant to the elaborated type.
+    ElaboratedTypeLoc NewTL = TLB.push<ElaboratedTypeLoc>(Result);
+    NewTL.setElaboratedKeywordLoc(TL.getElaboratedKeywordLoc());
+    NewTL.setQualifierLoc(QualifierLoc);
+  } else if (isa<DependentTemplateSpecializationType>(Result)) {
+    DependentTemplateSpecializationTypeLoc SpecTL
+      = TLB.push<DependentTemplateSpecializationTypeLoc>(Result);
+    SpecTL.setElaboratedKeywordLoc(TL.getElaboratedKeywordLoc());
+    SpecTL.setQualifierLoc(QualifierLoc);
+    SpecTL.setTemplateKeywordLoc(TL.getTemplateKeywordLoc());
+    SpecTL.setTemplateNameLoc(TL.getTemplateNameLoc());
+    SpecTL.setLAngleLoc(TL.getLAngleLoc());
+    SpecTL.setRAngleLoc(TL.getRAngleLoc());
+    for (unsigned I = 0, E = NewTemplateArgs.size(); I != E; ++I)
+      SpecTL.setArgLocInfo(I, NewTemplateArgs[I].getLocInfo());
+  } else {
+    TemplateSpecializationTypeLoc SpecTL
+      = TLB.push<TemplateSpecializationTypeLoc>(Result);
+    SpecTL.setTemplateKeywordLoc(TL.getTemplateKeywordLoc());
+    SpecTL.setTemplateNameLoc(TL.getTemplateNameLoc());
+    SpecTL.setLAngleLoc(TL.getLAngleLoc());
+    SpecTL.setRAngleLoc(TL.getRAngleLoc());
+    for (unsigned I = 0, E = NewTemplateArgs.size(); I != E; ++I)
+      SpecTL.setArgLocInfo(I, NewTemplateArgs[I].getLocInfo());
+  }
+  return Result;
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::TransformPackExpansionType(TypeLocBuilder &TLB,
+                                                      PackExpansionTypeLoc TL) {
+  QualType Pattern                                      
+    = getDerived().TransformType(TLB, TL.getPatternLoc());  
+  if (Pattern.isNull())
+    return QualType();
+  
+  QualType Result = TL.getType();  
+  if (getDerived().AlwaysRebuild() ||
+      Pattern != TL.getPatternLoc().getType()) {
+    Result = getDerived().RebuildPackExpansionType(Pattern, 
+                                           TL.getPatternLoc().getSourceRange(),
+                                                   TL.getEllipsisLoc(),
+                                           TL.getTypePtr()->getNumExpansions());
+    if (Result.isNull())
+      return QualType();
+  }
+  
+  PackExpansionTypeLoc NewT = TLB.push<PackExpansionTypeLoc>(Result);
+  NewT.setEllipsisLoc(TL.getEllipsisLoc());
+  return Result;
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformObjCInterfaceType(TypeLocBuilder &TLB,
+                                                   ObjCInterfaceTypeLoc TL) {
+  // ObjCInterfaceType is never dependent.
+  TLB.pushFullCopy(TL);
+  return TL.getType();
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformObjCObjectType(TypeLocBuilder &TLB,
+                                                ObjCObjectTypeLoc TL) {
+  // ObjCObjectType is never dependent.
+  TLB.pushFullCopy(TL);
+  return TL.getType();
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::TransformObjCObjectPointerType(TypeLocBuilder &TLB,
+                                               ObjCObjectPointerTypeLoc TL) {
+  // ObjCObjectPointerType is never dependent.
+  TLB.pushFullCopy(TL);
+  return TL.getType();
+}
+
+//===----------------------------------------------------------------------===//
+// Statement transformation
+//===----------------------------------------------------------------------===//
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformNullStmt(NullStmt *S) {
+  return SemaRef.Owned(S);
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformCompoundStmt(CompoundStmt *S) {
+  return getDerived().TransformCompoundStmt(S, false);
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformCompoundStmt(CompoundStmt *S,
+                                              bool IsStmtExpr) {
+  Sema::CompoundScopeRAII CompoundScope(getSema());
+
+  bool SubStmtInvalid = false;
+  bool SubStmtChanged = false;
+  ASTOwningVector<Stmt*> Statements(getSema());
+  for (CompoundStmt::body_iterator B = S->body_begin(), BEnd = S->body_end();
+       B != BEnd; ++B) {
+    StmtResult Result = getDerived().TransformStmt(*B);
+    if (Result.isInvalid()) {
+      // Immediately fail if this was a DeclStmt, since it's very
+      // likely that this will cause problems for future statements.
+      if (isa<DeclStmt>(*B))
+        return StmtError();
+
+      // Otherwise, just keep processing substatements and fail later.
+      SubStmtInvalid = true;
+      continue;
+    }
+
+    SubStmtChanged = SubStmtChanged || Result.get() != *B;
+    Statements.push_back(Result.takeAs<Stmt>());
+  }
+
+  if (SubStmtInvalid)
+    return StmtError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      !SubStmtChanged)
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildCompoundStmt(S->getLBracLoc(),
+                                          move_arg(Statements),
+                                          S->getRBracLoc(),
+                                          IsStmtExpr);
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformCaseStmt(CaseStmt *S) {
+  ExprResult LHS, RHS;
+  {
+    EnterExpressionEvaluationContext Unevaluated(SemaRef,
+                                                 Sema::ConstantEvaluated);
+
+    // Transform the left-hand case value.
+    LHS = getDerived().TransformExpr(S->getLHS());
+    LHS = SemaRef.ActOnConstantExpression(LHS);
+    if (LHS.isInvalid())
+      return StmtError();
+
+    // Transform the right-hand case value (for the GNU case-range extension).
+    RHS = getDerived().TransformExpr(S->getRHS());
+    RHS = SemaRef.ActOnConstantExpression(RHS);
+    if (RHS.isInvalid())
+      return StmtError();
+  }
+
+  // Build the case statement.
+  // Case statements are always rebuilt so that they will attached to their
+  // transformed switch statement.
+  StmtResult Case = getDerived().RebuildCaseStmt(S->getCaseLoc(),
+                                                       LHS.get(),
+                                                       S->getEllipsisLoc(),
+                                                       RHS.get(),
+                                                       S->getColonLoc());
+  if (Case.isInvalid())
+    return StmtError();
+
+  // Transform the statement following the case
+  StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+  if (SubStmt.isInvalid())
+    return StmtError();
+
+  // Attach the body to the case statement
+  return getDerived().RebuildCaseStmtBody(Case.get(), SubStmt.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformDefaultStmt(DefaultStmt *S) {
+  // Transform the statement following the default case
+  StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+  if (SubStmt.isInvalid())
+    return StmtError();
+
+  // Default statements are always rebuilt
+  return getDerived().RebuildDefaultStmt(S->getDefaultLoc(), S->getColonLoc(),
+                                         SubStmt.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformLabelStmt(LabelStmt *S) {
+  StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+  if (SubStmt.isInvalid())
+    return StmtError();
+
+  Decl *LD = getDerived().TransformDecl(S->getDecl()->getLocation(),
+                                        S->getDecl());
+  if (!LD)
+    return StmtError();
+
+
+  // FIXME: Pass the real colon location in.
+  return getDerived().RebuildLabelStmt(S->getIdentLoc(),
+                                       cast<LabelDecl>(LD), SourceLocation(),
+                                       SubStmt.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformAttributedStmt(AttributedStmt *S) {
+  StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+  if (SubStmt.isInvalid())
+    return StmtError();
+
+  // TODO: transform attributes
+  if (SubStmt.get() == S->getSubStmt() /* && attrs are the same */)
+    return S;
+
+  return getDerived().RebuildAttributedStmt(S->getAttrLoc(),
+                                            S->getAttrs(),
+                                            SubStmt.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
+  // Transform the condition
+  ExprResult Cond;
+  VarDecl *ConditionVar = 0;
+  if (S->getConditionVariable()) {
+    ConditionVar 
+      = cast_or_null<VarDecl>(
+                   getDerived().TransformDefinition(
+                                      S->getConditionVariable()->getLocation(),
+                                                    S->getConditionVariable()));
+    if (!ConditionVar)
+      return StmtError();
+  } else {
+    Cond = getDerived().TransformExpr(S->getCond());
+  
+    if (Cond.isInvalid())
+      return StmtError();
+    
+    // Convert the condition to a boolean value.
+    if (S->getCond()) {
+      ExprResult CondE = getSema().ActOnBooleanCondition(0, S->getIfLoc(), 
+                                                         Cond.get());
+      if (CondE.isInvalid())
+        return StmtError();
+    
+      Cond = CondE.get();
+    }
+  }
+  
+  Sema::FullExprArg FullCond(getSema().MakeFullExpr(Cond.take()));
+  if (!S->getConditionVariable() && S->getCond() && !FullCond.get())
+    return StmtError();
+  
+  // Transform the "then" branch.
+  StmtResult Then = getDerived().TransformStmt(S->getThen());
+  if (Then.isInvalid())
+    return StmtError();
+
+  // Transform the "else" branch.
+  StmtResult Else = getDerived().TransformStmt(S->getElse());
+  if (Else.isInvalid())
+    return StmtError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      FullCond.get() == S->getCond() &&
+      ConditionVar == S->getConditionVariable() &&
+      Then.get() == S->getThen() &&
+      Else.get() == S->getElse())
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildIfStmt(S->getIfLoc(), FullCond, ConditionVar,
+                                    Then.get(),
+                                    S->getElseLoc(), Else.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformSwitchStmt(SwitchStmt *S) {
+  // Transform the condition.
+  ExprResult Cond;
+  VarDecl *ConditionVar = 0;
+  if (S->getConditionVariable()) {
+    ConditionVar 
+      = cast_or_null<VarDecl>(
+                   getDerived().TransformDefinition(
+                                      S->getConditionVariable()->getLocation(),
+                                                    S->getConditionVariable()));
+    if (!ConditionVar)
+      return StmtError();
+  } else {
+    Cond = getDerived().TransformExpr(S->getCond());
+    
+    if (Cond.isInvalid())
+      return StmtError();
+  }
+
+  // Rebuild the switch statement.
+  StmtResult Switch
+    = getDerived().RebuildSwitchStmtStart(S->getSwitchLoc(), Cond.get(),
+                                          ConditionVar);
+  if (Switch.isInvalid())
+    return StmtError();
+
+  // Transform the body of the switch statement.
+  StmtResult Body = getDerived().TransformStmt(S->getBody());
+  if (Body.isInvalid())
+    return StmtError();
+
+  // Complete the switch statement.
+  return getDerived().RebuildSwitchStmtBody(S->getSwitchLoc(), Switch.get(),
+                                            Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformWhileStmt(WhileStmt *S) {
+  // Transform the condition
+  ExprResult Cond;
+  VarDecl *ConditionVar = 0;
+  if (S->getConditionVariable()) {
+    ConditionVar 
+      = cast_or_null<VarDecl>(
+                   getDerived().TransformDefinition(
+                                      S->getConditionVariable()->getLocation(),
+                                                    S->getConditionVariable()));
+    if (!ConditionVar)
+      return StmtError();
+  } else {
+    Cond = getDerived().TransformExpr(S->getCond());
+    
+    if (Cond.isInvalid())
+      return StmtError();
+
+    if (S->getCond()) {
+      // Convert the condition to a boolean value.
+      ExprResult CondE = getSema().ActOnBooleanCondition(0, S->getWhileLoc(), 
+                                                         Cond.get());
+      if (CondE.isInvalid())
+        return StmtError();
+      Cond = CondE;
+    }
+  }
+
+  Sema::FullExprArg FullCond(getSema().MakeFullExpr(Cond.take()));
+  if (!S->getConditionVariable() && S->getCond() && !FullCond.get())
+    return StmtError();
+
+  // Transform the body
+  StmtResult Body = getDerived().TransformStmt(S->getBody());
+  if (Body.isInvalid())
+    return StmtError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      FullCond.get() == S->getCond() &&
+      ConditionVar == S->getConditionVariable() &&
+      Body.get() == S->getBody())
+    return Owned(S);
+
+  return getDerived().RebuildWhileStmt(S->getWhileLoc(), FullCond,
+                                       ConditionVar, Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformDoStmt(DoStmt *S) {
+  // Transform the body
+  StmtResult Body = getDerived().TransformStmt(S->getBody());
+  if (Body.isInvalid())
+    return StmtError();
+
+  // Transform the condition
+  ExprResult Cond = getDerived().TransformExpr(S->getCond());
+  if (Cond.isInvalid())
+    return StmtError();
+  
+  if (!getDerived().AlwaysRebuild() &&
+      Cond.get() == S->getCond() &&
+      Body.get() == S->getBody())
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildDoStmt(S->getDoLoc(), Body.get(), S->getWhileLoc(),
+                                    /*FIXME:*/S->getWhileLoc(), Cond.get(),
+                                    S->getRParenLoc());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformForStmt(ForStmt *S) {
+  // Transform the initialization statement
+  StmtResult Init = getDerived().TransformStmt(S->getInit());
+  if (Init.isInvalid())
+    return StmtError();
+
+  // Transform the condition
+  ExprResult Cond;
+  VarDecl *ConditionVar = 0;
+  if (S->getConditionVariable()) {
+    ConditionVar 
+      = cast_or_null<VarDecl>(
+                   getDerived().TransformDefinition(
+                                      S->getConditionVariable()->getLocation(),
+                                                    S->getConditionVariable()));
+    if (!ConditionVar)
+      return StmtError();
+  } else {
+    Cond = getDerived().TransformExpr(S->getCond());
+    
+    if (Cond.isInvalid())
+      return StmtError();
+
+    if (S->getCond()) {
+      // Convert the condition to a boolean value.
+      ExprResult CondE = getSema().ActOnBooleanCondition(0, S->getForLoc(), 
+                                                         Cond.get());
+      if (CondE.isInvalid())
+        return StmtError();
+
+      Cond = CondE.get();
+    }
+  }
+
+  Sema::FullExprArg FullCond(getSema().MakeFullExpr(Cond.take()));  
+  if (!S->getConditionVariable() && S->getCond() && !FullCond.get())
+    return StmtError();
+
+  // Transform the increment
+  ExprResult Inc = getDerived().TransformExpr(S->getInc());
+  if (Inc.isInvalid())
+    return StmtError();
+
+  Sema::FullExprArg FullInc(getSema().MakeFullExpr(Inc.get()));
+  if (S->getInc() && !FullInc.get())
+    return StmtError();
+
+  // Transform the body
+  StmtResult Body = getDerived().TransformStmt(S->getBody());
+  if (Body.isInvalid())
+    return StmtError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Init.get() == S->getInit() &&
+      FullCond.get() == S->getCond() &&
+      Inc.get() == S->getInc() &&
+      Body.get() == S->getBody())
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildForStmt(S->getForLoc(), S->getLParenLoc(),
+                                     Init.get(), FullCond, ConditionVar,
+                                     FullInc, S->getRParenLoc(), Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformGotoStmt(GotoStmt *S) {
+  Decl *LD = getDerived().TransformDecl(S->getLabel()->getLocation(),
+                                        S->getLabel());
+  if (!LD)
+    return StmtError();
+  
+  // Goto statements must always be rebuilt, to resolve the label.
+  return getDerived().RebuildGotoStmt(S->getGotoLoc(), S->getLabelLoc(),
+                                      cast<LabelDecl>(LD));
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformIndirectGotoStmt(IndirectGotoStmt *S) {
+  ExprResult Target = getDerived().TransformExpr(S->getTarget());
+  if (Target.isInvalid())
+    return StmtError();
+  Target = SemaRef.MaybeCreateExprWithCleanups(Target.take());
+
+  if (!getDerived().AlwaysRebuild() &&
+      Target.get() == S->getTarget())
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildIndirectGotoStmt(S->getGotoLoc(), S->getStarLoc(),
+                                              Target.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformContinueStmt(ContinueStmt *S) {
+  return SemaRef.Owned(S);
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformBreakStmt(BreakStmt *S) {
+  return SemaRef.Owned(S);
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformReturnStmt(ReturnStmt *S) {
+  ExprResult Result = getDerived().TransformExpr(S->getRetValue());
+  if (Result.isInvalid())
+    return StmtError();
+
+  // FIXME: We always rebuild the return statement because there is no way
+  // to tell whether the return type of the function has changed.
+  return getDerived().RebuildReturnStmt(S->getReturnLoc(), Result.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformDeclStmt(DeclStmt *S) {
+  bool DeclChanged = false;
+  SmallVector<Decl *, 4> Decls;
+  for (DeclStmt::decl_iterator D = S->decl_begin(), DEnd = S->decl_end();
+       D != DEnd; ++D) {
+    Decl *Transformed = getDerived().TransformDefinition((*D)->getLocation(),
+                                                         *D);
+    if (!Transformed)
+      return StmtError();
+
+    if (Transformed != *D)
+      DeclChanged = true;
+
+    Decls.push_back(Transformed);
+  }
+
+  if (!getDerived().AlwaysRebuild() && !DeclChanged)
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildDeclStmt(Decls.data(), Decls.size(),
+                                      S->getStartLoc(), S->getEndLoc());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformAsmStmt(AsmStmt *S) {
+  
+  ASTOwningVector<Expr*> Constraints(getSema());
+  ASTOwningVector<Expr*> Exprs(getSema());
+  SmallVector<IdentifierInfo *, 4> Names;
+
+  ExprResult AsmString;
+  ASTOwningVector<Expr*> Clobbers(getSema());
+
+  bool ExprsChanged = false;
+  
+  // Go through the outputs.
+  for (unsigned I = 0, E = S->getNumOutputs(); I != E; ++I) {
+    Names.push_back(S->getOutputIdentifier(I));
+    
+    // No need to transform the constraint literal.
+    Constraints.push_back(S->getOutputConstraintLiteral(I));
+    
+    // Transform the output expr.
+    Expr *OutputExpr = S->getOutputExpr(I);
+    ExprResult Result = getDerived().TransformExpr(OutputExpr);
+    if (Result.isInvalid())
+      return StmtError();
+    
+    ExprsChanged |= Result.get() != OutputExpr;
+    
+    Exprs.push_back(Result.get());
+  }
+  
+  // Go through the inputs.
+  for (unsigned I = 0, E = S->getNumInputs(); I != E; ++I) {
+    Names.push_back(S->getInputIdentifier(I));
+    
+    // No need to transform the constraint literal.
+    Constraints.push_back(S->getInputConstraintLiteral(I));
+    
+    // Transform the input expr.
+    Expr *InputExpr = S->getInputExpr(I);
+    ExprResult Result = getDerived().TransformExpr(InputExpr);
+    if (Result.isInvalid())
+      return StmtError();
+    
+    ExprsChanged |= Result.get() != InputExpr;
+    
+    Exprs.push_back(Result.get());
+  }
+  
+  if (!getDerived().AlwaysRebuild() && !ExprsChanged)
+    return SemaRef.Owned(S);
+
+  // Go through the clobbers.
+  for (unsigned I = 0, E = S->getNumClobbers(); I != E; ++I)
+    Clobbers.push_back(S->getClobber(I));
+
+  // No need to transform the asm string literal.
+  AsmString = SemaRef.Owned(S->getAsmString());
+
+  return getDerived().RebuildAsmStmt(S->getAsmLoc(),
+                                     S->isSimple(),
+                                     S->isVolatile(),
+                                     S->getNumOutputs(),
+                                     S->getNumInputs(),
+                                     Names.data(),
+                                     move_arg(Constraints),
+                                     move_arg(Exprs),
+                                     AsmString.get(),
+                                     move_arg(Clobbers),
+                                     S->getRParenLoc(),
+                                     S->isMSAsm());
+}
+
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformObjCAtTryStmt(ObjCAtTryStmt *S) {
+  // Transform the body of the @try.
+  StmtResult TryBody = getDerived().TransformStmt(S->getTryBody());
+  if (TryBody.isInvalid())
+    return StmtError();
+  
+  // Transform the @catch statements (if present).
+  bool AnyCatchChanged = false;
+  ASTOwningVector<Stmt*> CatchStmts(SemaRef);
+  for (unsigned I = 0, N = S->getNumCatchStmts(); I != N; ++I) {
+    StmtResult Catch = getDerived().TransformStmt(S->getCatchStmt(I));
+    if (Catch.isInvalid())
+      return StmtError();
+    if (Catch.get() != S->getCatchStmt(I))
+      AnyCatchChanged = true;
+    CatchStmts.push_back(Catch.release());
+  }
+  
+  // Transform the @finally statement (if present).
+  StmtResult Finally;
+  if (S->getFinallyStmt()) {
+    Finally = getDerived().TransformStmt(S->getFinallyStmt());
+    if (Finally.isInvalid())
+      return StmtError();
+  }
+
+  // If nothing changed, just retain this statement.
+  if (!getDerived().AlwaysRebuild() &&
+      TryBody.get() == S->getTryBody() &&
+      !AnyCatchChanged &&
+      Finally.get() == S->getFinallyStmt())
+    return SemaRef.Owned(S);
+  
+  // Build a new statement.
+  return getDerived().RebuildObjCAtTryStmt(S->getAtTryLoc(), TryBody.get(),
+                                           move_arg(CatchStmts), Finally.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformObjCAtCatchStmt(ObjCAtCatchStmt *S) {
+  // Transform the @catch parameter, if there is one.
+  VarDecl *Var = 0;
+  if (VarDecl *FromVar = S->getCatchParamDecl()) {
+    TypeSourceInfo *TSInfo = 0;
+    if (FromVar->getTypeSourceInfo()) {
+      TSInfo = getDerived().TransformType(FromVar->getTypeSourceInfo());
+      if (!TSInfo)
+        return StmtError();
+    }
+    
+    QualType T;
+    if (TSInfo)
+      T = TSInfo->getType();
+    else {
+      T = getDerived().TransformType(FromVar->getType());
+      if (T.isNull())
+        return StmtError();        
+    }
+    
+    Var = getDerived().RebuildObjCExceptionDecl(FromVar, TSInfo, T);
+    if (!Var)
+      return StmtError();
+  }
+  
+  StmtResult Body = getDerived().TransformStmt(S->getCatchBody());
+  if (Body.isInvalid())
+    return StmtError();
+  
+  return getDerived().RebuildObjCAtCatchStmt(S->getAtCatchLoc(), 
+                                             S->getRParenLoc(),
+                                             Var, Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformObjCAtFinallyStmt(ObjCAtFinallyStmt *S) {
+  // Transform the body.
+  StmtResult Body = getDerived().TransformStmt(S->getFinallyBody());
+  if (Body.isInvalid())
+    return StmtError();
+  
+  // If nothing changed, just retain this statement.
+  if (!getDerived().AlwaysRebuild() &&
+      Body.get() == S->getFinallyBody())
+    return SemaRef.Owned(S);
+
+  // Build a new statement.
+  return getDerived().RebuildObjCAtFinallyStmt(S->getAtFinallyLoc(),
+                                               Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformObjCAtThrowStmt(ObjCAtThrowStmt *S) {
+  ExprResult Operand;
+  if (S->getThrowExpr()) {
+    Operand = getDerived().TransformExpr(S->getThrowExpr());
+    if (Operand.isInvalid())
+      return StmtError();
+  }
+  
+  if (!getDerived().AlwaysRebuild() &&
+      Operand.get() == S->getThrowExpr())
+    return getSema().Owned(S);
+    
+  return getDerived().RebuildObjCAtThrowStmt(S->getThrowLoc(), Operand.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformObjCAtSynchronizedStmt(
+                                                  ObjCAtSynchronizedStmt *S) {
+  // Transform the object we are locking.
+  ExprResult Object = getDerived().TransformExpr(S->getSynchExpr());
+  if (Object.isInvalid())
+    return StmtError();
+  Object =
+    getDerived().RebuildObjCAtSynchronizedOperand(S->getAtSynchronizedLoc(),
+                                                  Object.get());
+  if (Object.isInvalid())
+    return StmtError();
+  
+  // Transform the body.
+  StmtResult Body = getDerived().TransformStmt(S->getSynchBody());
+  if (Body.isInvalid())
+    return StmtError();
+  
+  // If nothing change, just retain the current statement.
+  if (!getDerived().AlwaysRebuild() &&
+      Object.get() == S->getSynchExpr() &&
+      Body.get() == S->getSynchBody())
+    return SemaRef.Owned(S);
+
+  // Build a new statement.
+  return getDerived().RebuildObjCAtSynchronizedStmt(S->getAtSynchronizedLoc(),
+                                                    Object.get(), Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformObjCAutoreleasePoolStmt(
+                                              ObjCAutoreleasePoolStmt *S) {
+  // Transform the body.
+  StmtResult Body = getDerived().TransformStmt(S->getSubStmt());
+  if (Body.isInvalid())
+    return StmtError();
+  
+  // If nothing changed, just retain this statement.
+  if (!getDerived().AlwaysRebuild() &&
+      Body.get() == S->getSubStmt())
+    return SemaRef.Owned(S);
+
+  // Build a new statement.
+  return getDerived().RebuildObjCAutoreleasePoolStmt(
+                        S->getAtLoc(), Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformObjCForCollectionStmt(
+                                                  ObjCForCollectionStmt *S) {
+  // Transform the element statement.
+  StmtResult Element = getDerived().TransformStmt(S->getElement());
+  if (Element.isInvalid())
+    return StmtError();
+  
+  // Transform the collection expression.
+  ExprResult Collection = getDerived().TransformExpr(S->getCollection());
+  if (Collection.isInvalid())
+    return StmtError();
+  Collection = getDerived().RebuildObjCForCollectionOperand(S->getForLoc(),
+                                                            Collection.take());
+  if (Collection.isInvalid())
+    return StmtError();
+  
+  // Transform the body.
+  StmtResult Body = getDerived().TransformStmt(S->getBody());
+  if (Body.isInvalid())
+    return StmtError();
+  
+  // If nothing changed, just retain this statement.
+  if (!getDerived().AlwaysRebuild() &&
+      Element.get() == S->getElement() &&
+      Collection.get() == S->getCollection() &&
+      Body.get() == S->getBody())
+    return SemaRef.Owned(S);
+  
+  // Build a new statement.
+  return getDerived().RebuildObjCForCollectionStmt(S->getForLoc(),
+                                                   /*FIXME:*/S->getForLoc(),
+                                                   Element.get(),
+                                                   Collection.get(),
+                                                   S->getRParenLoc(),
+                                                   Body.get());
+}
+
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformCXXCatchStmt(CXXCatchStmt *S) {
+  // Transform the exception declaration, if any.
+  VarDecl *Var = 0;
+  if (S->getExceptionDecl()) {
+    VarDecl *ExceptionDecl = S->getExceptionDecl();
+    TypeSourceInfo *T = getDerived().TransformType(
+                                            ExceptionDecl->getTypeSourceInfo());
+    if (!T)
+      return StmtError();
+
+    Var = getDerived().RebuildExceptionDecl(ExceptionDecl, T,
+                                            ExceptionDecl->getInnerLocStart(),
+                                            ExceptionDecl->getLocation(),
+                                            ExceptionDecl->getIdentifier());
+    if (!Var || Var->isInvalidDecl())
+      return StmtError();
+  }
+
+  // Transform the actual exception handler.
+  StmtResult Handler = getDerived().TransformStmt(S->getHandlerBlock());
+  if (Handler.isInvalid())
+    return StmtError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      !Var &&
+      Handler.get() == S->getHandlerBlock())
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildCXXCatchStmt(S->getCatchLoc(),
+                                          Var,
+                                          Handler.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformCXXTryStmt(CXXTryStmt *S) {
+  // Transform the try block itself.
+  StmtResult TryBlock
+    = getDerived().TransformCompoundStmt(S->getTryBlock());
+  if (TryBlock.isInvalid())
+    return StmtError();
+
+  // Transform the handlers.
+  bool HandlerChanged = false;
+  ASTOwningVector<Stmt*> Handlers(SemaRef);
+  for (unsigned I = 0, N = S->getNumHandlers(); I != N; ++I) {
+    StmtResult Handler
+      = getDerived().TransformCXXCatchStmt(S->getHandler(I));
+    if (Handler.isInvalid())
+      return StmtError();
+
+    HandlerChanged = HandlerChanged || Handler.get() != S->getHandler(I);
+    Handlers.push_back(Handler.takeAs<Stmt>());
+  }
+
+  if (!getDerived().AlwaysRebuild() &&
+      TryBlock.get() == S->getTryBlock() &&
+      !HandlerChanged)
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildCXXTryStmt(S->getTryLoc(), TryBlock.get(),
+                                        move_arg(Handlers));
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformCXXForRangeStmt(CXXForRangeStmt *S) {
+  StmtResult Range = getDerived().TransformStmt(S->getRangeStmt());
+  if (Range.isInvalid())
+    return StmtError();
+
+  StmtResult BeginEnd = getDerived().TransformStmt(S->getBeginEndStmt());
+  if (BeginEnd.isInvalid())
+    return StmtError();
+
+  ExprResult Cond = getDerived().TransformExpr(S->getCond());
+  if (Cond.isInvalid())
+    return StmtError();
+  if (Cond.get())
+    Cond = SemaRef.CheckBooleanCondition(Cond.take(), S->getColonLoc());
+  if (Cond.isInvalid())
+    return StmtError();
+  if (Cond.get())
+    Cond = SemaRef.MaybeCreateExprWithCleanups(Cond.take());
+
+  ExprResult Inc = getDerived().TransformExpr(S->getInc());
+  if (Inc.isInvalid())
+    return StmtError();
+  if (Inc.get())
+    Inc = SemaRef.MaybeCreateExprWithCleanups(Inc.take());
+
+  StmtResult LoopVar = getDerived().TransformStmt(S->getLoopVarStmt());
+  if (LoopVar.isInvalid())
+    return StmtError();
+
+  StmtResult NewStmt = S;
+  if (getDerived().AlwaysRebuild() ||
+      Range.get() != S->getRangeStmt() ||
+      BeginEnd.get() != S->getBeginEndStmt() ||
+      Cond.get() != S->getCond() ||
+      Inc.get() != S->getInc() ||
+      LoopVar.get() != S->getLoopVarStmt())
+    NewStmt = getDerived().RebuildCXXForRangeStmt(S->getForLoc(),
+                                                  S->getColonLoc(), Range.get(),
+                                                  BeginEnd.get(), Cond.get(),
+                                                  Inc.get(), LoopVar.get(),
+                                                  S->getRParenLoc());
+
+  StmtResult Body = getDerived().TransformStmt(S->getBody());
+  if (Body.isInvalid())
+    return StmtError();
+
+  // Body has changed but we didn't rebuild the for-range statement. Rebuild
+  // it now so we have a new statement to attach the body to.
+  if (Body.get() != S->getBody() && NewStmt.get() == S)
+    NewStmt = getDerived().RebuildCXXForRangeStmt(S->getForLoc(),
+                                                  S->getColonLoc(), Range.get(),
+                                                  BeginEnd.get(), Cond.get(),
+                                                  Inc.get(), LoopVar.get(),
+                                                  S->getRParenLoc());
+
+  if (NewStmt.get() == S)
+    return SemaRef.Owned(S);
+
+  return FinishCXXForRangeStmt(NewStmt.get(), Body.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformMSDependentExistsStmt(
+                                                    MSDependentExistsStmt *S) {
+  // Transform the nested-name-specifier, if any.
+  NestedNameSpecifierLoc QualifierLoc;
+  if (S->getQualifierLoc()) {
+    QualifierLoc 
+      = getDerived().TransformNestedNameSpecifierLoc(S->getQualifierLoc());
+    if (!QualifierLoc)
+      return StmtError();
+  }
+
+  // Transform the declaration name.
+  DeclarationNameInfo NameInfo = S->getNameInfo();
+  if (NameInfo.getName()) {
+    NameInfo = getDerived().TransformDeclarationNameInfo(NameInfo);
+    if (!NameInfo.getName())
+      return StmtError();
+  }
+
+  // Check whether anything changed.
+  if (!getDerived().AlwaysRebuild() &&
+      QualifierLoc == S->getQualifierLoc() &&
+      NameInfo.getName() == S->getNameInfo().getName())
+    return S;
+  
+  // Determine whether this name exists, if we can.
+  CXXScopeSpec SS;
+  SS.Adopt(QualifierLoc);
+  bool Dependent = false;
+  switch (getSema().CheckMicrosoftIfExistsSymbol(/*S=*/0, SS, NameInfo)) {
+  case Sema::IER_Exists:
+    if (S->isIfExists())
+      break;
+      
+    return new (getSema().Context) NullStmt(S->getKeywordLoc());
+
+  case Sema::IER_DoesNotExist:
+    if (S->isIfNotExists())
+      break;
+    
+    return new (getSema().Context) NullStmt(S->getKeywordLoc());
+      
+  case Sema::IER_Dependent:
+    Dependent = true;
+    break;
+      
+  case Sema::IER_Error:
+    return StmtError();
+  }
+  
+  // We need to continue with the instantiation, so do so now.
+  StmtResult SubStmt = getDerived().TransformCompoundStmt(S->getSubStmt());
+  if (SubStmt.isInvalid())
+    return StmtError();
+  
+  // If we have resolved the name, just transform to the substatement.
+  if (!Dependent)
+    return SubStmt;
+  
+  // The name is still dependent, so build a dependent expression again.
+  return getDerived().RebuildMSDependentExistsStmt(S->getKeywordLoc(),
+                                                   S->isIfExists(),
+                                                   QualifierLoc,
+                                                   NameInfo,
+                                                   SubStmt.get());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformSEHTryStmt(SEHTryStmt *S) {
+  StmtResult TryBlock; //  = getDerived().TransformCompoundStmt(S->getTryBlock());
+  if(TryBlock.isInvalid()) return StmtError();
+
+  StmtResult Handler = getDerived().TransformSEHHandler(S->getHandler());
+  if(!getDerived().AlwaysRebuild() &&
+     TryBlock.get() == S->getTryBlock() &&
+     Handler.get() == S->getHandler())
+    return SemaRef.Owned(S);
+
+  return getDerived().RebuildSEHTryStmt(S->getIsCXXTry(),
+                                        S->getTryLoc(),
+                                        TryBlock.take(),
+                                        Handler.take());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformSEHFinallyStmt(SEHFinallyStmt *S) {
+  StmtResult Block; //  = getDerived().TransformCompoundStatement(S->getBlock());
+  if(Block.isInvalid()) return StmtError();
+
+  return getDerived().RebuildSEHFinallyStmt(S->getFinallyLoc(),
+                                            Block.take());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformSEHExceptStmt(SEHExceptStmt *S) {
+  ExprResult FilterExpr = getDerived().TransformExpr(S->getFilterExpr());
+  if(FilterExpr.isInvalid()) return StmtError();
+
+  StmtResult Block; //  = getDerived().TransformCompoundStatement(S->getBlock());
+  if(Block.isInvalid()) return StmtError();
+
+  return getDerived().RebuildSEHExceptStmt(S->getExceptLoc(),
+                                           FilterExpr.take(),
+                                           Block.take());
+}
+
+template<typename Derived>
+StmtResult
+TreeTransform<Derived>::TransformSEHHandler(Stmt *Handler) {
+  if(isa<SEHFinallyStmt>(Handler))
+    return getDerived().TransformSEHFinallyStmt(cast<SEHFinallyStmt>(Handler));
+  else
+    return getDerived().TransformSEHExceptStmt(cast<SEHExceptStmt>(Handler));
+}
+
+//===----------------------------------------------------------------------===//
+// Expression transformation
+//===----------------------------------------------------------------------===//
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformPredefinedExpr(PredefinedExpr *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformDeclRefExpr(DeclRefExpr *E) {
+  NestedNameSpecifierLoc QualifierLoc;
+  if (E->getQualifierLoc()) {
+    QualifierLoc
+      = getDerived().TransformNestedNameSpecifierLoc(E->getQualifierLoc());
+    if (!QualifierLoc)
+      return ExprError();
+  }
+
+  ValueDecl *ND
+    = cast_or_null<ValueDecl>(getDerived().TransformDecl(E->getLocation(),
+                                                         E->getDecl()));
+  if (!ND)
+    return ExprError();
+
+  DeclarationNameInfo NameInfo = E->getNameInfo();
+  if (NameInfo.getName()) {
+    NameInfo = getDerived().TransformDeclarationNameInfo(NameInfo);
+    if (!NameInfo.getName())
+      return ExprError();
+  }
+
+  if (!getDerived().AlwaysRebuild() &&
+      QualifierLoc == E->getQualifierLoc() &&
+      ND == E->getDecl() &&
+      NameInfo.getName() == E->getDecl()->getDeclName() &&
+      !E->hasExplicitTemplateArgs()) {
+
+    // Mark it referenced in the new context regardless.
+    // FIXME: this is a bit instantiation-specific.
+    SemaRef.MarkDeclRefReferenced(E);
+
+    return SemaRef.Owned(E);
+  }
+
+  TemplateArgumentListInfo TransArgs, *TemplateArgs = 0;
+  if (E->hasExplicitTemplateArgs()) {
+    TemplateArgs = &TransArgs;
+    TransArgs.setLAngleLoc(E->getLAngleLoc());
+    TransArgs.setRAngleLoc(E->getRAngleLoc());
+    if (getDerived().TransformTemplateArguments(E->getTemplateArgs(),
+                                                E->getNumTemplateArgs(),
+                                                TransArgs))
+      return ExprError();
+  }
+
+  return getDerived().RebuildDeclRefExpr(QualifierLoc, ND, NameInfo, 
+                                         TemplateArgs);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformIntegerLiteral(IntegerLiteral *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformFloatingLiteral(FloatingLiteral *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformImaginaryLiteral(ImaginaryLiteral *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformStringLiteral(StringLiteral *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCharacterLiteral(CharacterLiteral *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformUserDefinedLiteral(UserDefinedLiteral *E) {
+  return SemaRef.MaybeBindToTemporary(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformGenericSelectionExpr(GenericSelectionExpr *E) {
+  ExprResult ControllingExpr =
+    getDerived().TransformExpr(E->getControllingExpr());
+  if (ControllingExpr.isInvalid())
+    return ExprError();
+
+  SmallVector<Expr *, 4> AssocExprs;
+  SmallVector<TypeSourceInfo *, 4> AssocTypes;
+  for (unsigned i = 0; i != E->getNumAssocs(); ++i) {
+    TypeSourceInfo *TS = E->getAssocTypeSourceInfo(i);
+    if (TS) {
+      TypeSourceInfo *AssocType = getDerived().TransformType(TS);
+      if (!AssocType)
+        return ExprError();
+      AssocTypes.push_back(AssocType);
+    } else {
+      AssocTypes.push_back(0);
+    }
+
+    ExprResult AssocExpr = getDerived().TransformExpr(E->getAssocExpr(i));
+    if (AssocExpr.isInvalid())
+      return ExprError();
+    AssocExprs.push_back(AssocExpr.release());
+  }
+
+  return getDerived().RebuildGenericSelectionExpr(E->getGenericLoc(),
+                                                  E->getDefaultLoc(),
+                                                  E->getRParenLoc(),
+                                                  ControllingExpr.release(),
+                                                  AssocTypes.data(),
+                                                  AssocExprs.data(),
+                                                  E->getNumAssocs());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformParenExpr(ParenExpr *E) {
+  ExprResult SubExpr = getDerived().TransformExpr(E->getSubExpr());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() && SubExpr.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildParenExpr(SubExpr.get(), E->getLParen(),
+                                       E->getRParen());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformUnaryOperator(UnaryOperator *E) {
+  ExprResult SubExpr = getDerived().TransformExpr(E->getSubExpr());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() && SubExpr.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildUnaryOperator(E->getOperatorLoc(),
+                                           E->getOpcode(),
+                                           SubExpr.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformOffsetOfExpr(OffsetOfExpr *E) {
+  // Transform the type.
+  TypeSourceInfo *Type = getDerived().TransformType(E->getTypeSourceInfo());
+  if (!Type)
+    return ExprError();
+  
+  // Transform all of the components into components similar to what the
+  // parser uses.
+  // FIXME: It would be slightly more efficient in the non-dependent case to 
+  // just map FieldDecls, rather than requiring the rebuilder to look for 
+  // the fields again. However, __builtin_offsetof is rare enough in 
+  // template code that we don't care.
+  bool ExprChanged = false;
+  typedef Sema::OffsetOfComponent Component;
+  typedef OffsetOfExpr::OffsetOfNode Node;
+  SmallVector<Component, 4> Components;
+  for (unsigned I = 0, N = E->getNumComponents(); I != N; ++I) {
+    const Node &ON = E->getComponent(I);
+    Component Comp;
+    Comp.isBrackets = true;
+    Comp.LocStart = ON.getSourceRange().getBegin();
+    Comp.LocEnd = ON.getSourceRange().getEnd();
+    switch (ON.getKind()) {
+    case Node::Array: {
+      Expr *FromIndex = E->getIndexExpr(ON.getArrayExprIndex());
+      ExprResult Index = getDerived().TransformExpr(FromIndex);
+      if (Index.isInvalid())
+        return ExprError();
+      
+      ExprChanged = ExprChanged || Index.get() != FromIndex;
+      Comp.isBrackets = true;
+      Comp.U.E = Index.get();
+      break;
+    }
+        
+    case Node::Field:
+    case Node::Identifier:
+      Comp.isBrackets = false;
+      Comp.U.IdentInfo = ON.getFieldName();
+      if (!Comp.U.IdentInfo)
+        continue;
+        
+      break;
+        
+    case Node::Base:
+      // Will be recomputed during the rebuild.
+      continue;
+    }
+    
+    Components.push_back(Comp);
+  }
+  
+  // If nothing changed, retain the existing expression.
+  if (!getDerived().AlwaysRebuild() &&
+      Type == E->getTypeSourceInfo() &&
+      !ExprChanged)
+    return SemaRef.Owned(E);
+  
+  // Build a new offsetof expression.
+  return getDerived().RebuildOffsetOfExpr(E->getOperatorLoc(), Type,
+                                          Components.data(), Components.size(),
+                                          E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformOpaqueValueExpr(OpaqueValueExpr *E) {
+  assert(getDerived().AlreadyTransformed(E->getType()) &&
+         "opaque value expression requires transformation");
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformPseudoObjectExpr(PseudoObjectExpr *E) {
+  // Rebuild the syntactic form.  The original syntactic form has
+  // opaque-value expressions in it, so strip those away and rebuild
+  // the result.  This is a really awful way of doing this, but the
+  // better solution (rebuilding the semantic expressions and
+  // rebinding OVEs as necessary) doesn't work; we'd need
+  // TreeTransform to not strip away implicit conversions.
+  Expr *newSyntacticForm = SemaRef.recreateSyntacticForm(E);
+  ExprResult result = getDerived().TransformExpr(newSyntacticForm);
+  if (result.isInvalid()) return ExprError();
+
+  // If that gives us a pseudo-object result back, the pseudo-object
+  // expression must have been an lvalue-to-rvalue conversion which we
+  // should reapply.
+  if (result.get()->hasPlaceholderType(BuiltinType::PseudoObject))
+    result = SemaRef.checkPseudoObjectRValue(result.take());
+
+  return result;
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformUnaryExprOrTypeTraitExpr(
+                                                UnaryExprOrTypeTraitExpr *E) {
+  if (E->isArgumentType()) {
+    TypeSourceInfo *OldT = E->getArgumentTypeInfo();
+
+    TypeSourceInfo *NewT = getDerived().TransformType(OldT);
+    if (!NewT)
+      return ExprError();
+
+    if (!getDerived().AlwaysRebuild() && OldT == NewT)
+      return SemaRef.Owned(E);
+
+    return getDerived().RebuildUnaryExprOrTypeTrait(NewT, E->getOperatorLoc(),
+                                                    E->getKind(),
+                                                    E->getSourceRange());
+  }
+
+  // C++0x [expr.sizeof]p1:
+  //   The operand is either an expression, which is an unevaluated operand
+  //   [...]
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+
+  ExprResult SubExpr = getDerived().TransformExpr(E->getArgumentExpr());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() && SubExpr.get() == E->getArgumentExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildUnaryExprOrTypeTrait(SubExpr.get(),
+                                                  E->getOperatorLoc(),
+                                                  E->getKind(),
+                                                  E->getSourceRange());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformArraySubscriptExpr(ArraySubscriptExpr *E) {
+  ExprResult LHS = getDerived().TransformExpr(E->getLHS());
+  if (LHS.isInvalid())
+    return ExprError();
+
+  ExprResult RHS = getDerived().TransformExpr(E->getRHS());
+  if (RHS.isInvalid())
+    return ExprError();
+
+
+  if (!getDerived().AlwaysRebuild() &&
+      LHS.get() == E->getLHS() &&
+      RHS.get() == E->getRHS())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildArraySubscriptExpr(LHS.get(),
+                                           /*FIXME:*/E->getLHS()->getLocStart(),
+                                                RHS.get(),
+                                                E->getRBracketLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCallExpr(CallExpr *E) {
+  // Transform the callee.
+  ExprResult Callee = getDerived().TransformExpr(E->getCallee());
+  if (Callee.isInvalid())
+    return ExprError();
+
+  // Transform arguments.
+  bool ArgChanged = false;
+  ASTOwningVector<Expr*> Args(SemaRef);
+  if (getDerived().TransformExprs(E->getArgs(), E->getNumArgs(), true, Args, 
+                                  &ArgChanged))
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() &&
+      Callee.get() == E->getCallee() &&
+      !ArgChanged)
+    return SemaRef.MaybeBindToTemporary(E);;
+
+  // FIXME: Wrong source location information for the '('.
+  SourceLocation FakeLParenLoc
+    = ((Expr *)Callee.get())->getSourceRange().getBegin();
+  return getDerived().RebuildCallExpr(Callee.get(), FakeLParenLoc,
+                                      move_arg(Args),
+                                      E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformMemberExpr(MemberExpr *E) {
+  ExprResult Base = getDerived().TransformExpr(E->getBase());
+  if (Base.isInvalid())
+    return ExprError();
+
+  NestedNameSpecifierLoc QualifierLoc;
+  if (E->hasQualifier()) {
+    QualifierLoc
+      = getDerived().TransformNestedNameSpecifierLoc(E->getQualifierLoc());
+    
+    if (!QualifierLoc)
+      return ExprError();
+  }
+  SourceLocation TemplateKWLoc = E->getTemplateKeywordLoc();
+
+  ValueDecl *Member
+    = cast_or_null<ValueDecl>(getDerived().TransformDecl(E->getMemberLoc(),
+                                                         E->getMemberDecl()));
+  if (!Member)
+    return ExprError();
+
+  NamedDecl *FoundDecl = E->getFoundDecl();
+  if (FoundDecl == E->getMemberDecl()) {
+    FoundDecl = Member;
+  } else {
+    FoundDecl = cast_or_null<NamedDecl>(
+                   getDerived().TransformDecl(E->getMemberLoc(), FoundDecl));
+    if (!FoundDecl)
+      return ExprError();
+  }
+
+  if (!getDerived().AlwaysRebuild() &&
+      Base.get() == E->getBase() &&
+      QualifierLoc == E->getQualifierLoc() &&
+      Member == E->getMemberDecl() &&
+      FoundDecl == E->getFoundDecl() &&
+      !E->hasExplicitTemplateArgs()) {
+    
+    // Mark it referenced in the new context regardless.
+    // FIXME: this is a bit instantiation-specific.
+    SemaRef.MarkMemberReferenced(E);
+
+    return SemaRef.Owned(E);
+  }
+
+  TemplateArgumentListInfo TransArgs;
+  if (E->hasExplicitTemplateArgs()) {
+    TransArgs.setLAngleLoc(E->getLAngleLoc());
+    TransArgs.setRAngleLoc(E->getRAngleLoc());
+    if (getDerived().TransformTemplateArguments(E->getTemplateArgs(),
+                                                E->getNumTemplateArgs(),
+                                                TransArgs))
+      return ExprError();
+  }
+  
+  // FIXME: Bogus source location for the operator
+  SourceLocation FakeOperatorLoc
+    = SemaRef.PP.getLocForEndOfToken(E->getBase()->getSourceRange().getEnd());
+
+  // FIXME: to do this check properly, we will need to preserve the
+  // first-qualifier-in-scope here, just in case we had a dependent
+  // base (and therefore couldn't do the check) and a
+  // nested-name-qualifier (and therefore could do the lookup).
+  NamedDecl *FirstQualifierInScope = 0;
+
+  return getDerived().RebuildMemberExpr(Base.get(), FakeOperatorLoc,
+                                        E->isArrow(),
+                                        QualifierLoc,
+                                        TemplateKWLoc,
+                                        E->getMemberNameInfo(),
+                                        Member,
+                                        FoundDecl,
+                                        (E->hasExplicitTemplateArgs()
+                                           ? &TransArgs : 0),
+                                        FirstQualifierInScope);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformBinaryOperator(BinaryOperator *E) {
+  ExprResult LHS = getDerived().TransformExpr(E->getLHS());
+  if (LHS.isInvalid())
+    return ExprError();
+
+  ExprResult RHS = getDerived().TransformExpr(E->getRHS());
+  if (RHS.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      LHS.get() == E->getLHS() &&
+      RHS.get() == E->getRHS())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildBinaryOperator(E->getOperatorLoc(), E->getOpcode(),
+                                            LHS.get(), RHS.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCompoundAssignOperator(
+                                                      CompoundAssignOperator *E) {
+  return getDerived().TransformBinaryOperator(E);
+}
+
+template<typename Derived>
+ExprResult TreeTransform<Derived>::
+TransformBinaryConditionalOperator(BinaryConditionalOperator *e) {
+  // Just rebuild the common and RHS expressions and see whether we
+  // get any changes.
+
+  ExprResult commonExpr = getDerived().TransformExpr(e->getCommon());
+  if (commonExpr.isInvalid())
+    return ExprError();
+
+  ExprResult rhs = getDerived().TransformExpr(e->getFalseExpr());
+  if (rhs.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      commonExpr.get() == e->getCommon() &&
+      rhs.get() == e->getFalseExpr())
+    return SemaRef.Owned(e);
+
+  return getDerived().RebuildConditionalOperator(commonExpr.take(),
+                                                 e->getQuestionLoc(),
+                                                 0,
+                                                 e->getColonLoc(),
+                                                 rhs.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformConditionalOperator(ConditionalOperator *E) {
+  ExprResult Cond = getDerived().TransformExpr(E->getCond());
+  if (Cond.isInvalid())
+    return ExprError();
+
+  ExprResult LHS = getDerived().TransformExpr(E->getLHS());
+  if (LHS.isInvalid())
+    return ExprError();
+
+  ExprResult RHS = getDerived().TransformExpr(E->getRHS());
+  if (RHS.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Cond.get() == E->getCond() &&
+      LHS.get() == E->getLHS() &&
+      RHS.get() == E->getRHS())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildConditionalOperator(Cond.get(),
+                                                 E->getQuestionLoc(),
+                                                 LHS.get(),
+                                                 E->getColonLoc(),
+                                                 RHS.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformImplicitCastExpr(ImplicitCastExpr *E) {
+  // Implicit casts are eliminated during transformation, since they
+  // will be recomputed by semantic analysis after transformation.
+  return getDerived().TransformExpr(E->getSubExprAsWritten());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCStyleCastExpr(CStyleCastExpr *E) {
+  TypeSourceInfo *Type = getDerived().TransformType(E->getTypeInfoAsWritten());
+  if (!Type)
+    return ExprError();
+  
+  ExprResult SubExpr
+    = getDerived().TransformExpr(E->getSubExprAsWritten());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Type == E->getTypeInfoAsWritten() &&
+      SubExpr.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCStyleCastExpr(E->getLParenLoc(),
+                                            Type,
+                                            E->getRParenLoc(),
+                                            SubExpr.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCompoundLiteralExpr(CompoundLiteralExpr *E) {
+  TypeSourceInfo *OldT = E->getTypeSourceInfo();
+  TypeSourceInfo *NewT = getDerived().TransformType(OldT);
+  if (!NewT)
+    return ExprError();
+
+  ExprResult Init = getDerived().TransformExpr(E->getInitializer());
+  if (Init.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      OldT == NewT &&
+      Init.get() == E->getInitializer())
+    return SemaRef.MaybeBindToTemporary(E);
+
+  // Note: the expression type doesn't necessarily match the
+  // type-as-written, but that's okay, because it should always be
+  // derivable from the initializer.
+
+  return getDerived().RebuildCompoundLiteralExpr(E->getLParenLoc(), NewT,
+                                   /*FIXME:*/E->getInitializer()->getLocEnd(),
+                                                 Init.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformExtVectorElementExpr(ExtVectorElementExpr *E) {
+  ExprResult Base = getDerived().TransformExpr(E->getBase());
+  if (Base.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Base.get() == E->getBase())
+    return SemaRef.Owned(E);
+
+  // FIXME: Bad source location
+  SourceLocation FakeOperatorLoc
+    = SemaRef.PP.getLocForEndOfToken(E->getBase()->getLocEnd());
+  return getDerived().RebuildExtVectorElementExpr(Base.get(), FakeOperatorLoc,
+                                                  E->getAccessorLoc(),
+                                                  E->getAccessor());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformInitListExpr(InitListExpr *E) {
+  bool InitChanged = false;
+
+  ASTOwningVector<Expr*, 4> Inits(SemaRef);
+  if (getDerived().TransformExprs(E->getInits(), E->getNumInits(), false, 
+                                  Inits, &InitChanged))
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() && !InitChanged)
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildInitList(E->getLBraceLoc(), move_arg(Inits),
+                                      E->getRBraceLoc(), E->getType());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformDesignatedInitExpr(DesignatedInitExpr *E) {
+  Designation Desig;
+
+  // transform the initializer value
+  ExprResult Init = getDerived().TransformExpr(E->getInit());
+  if (Init.isInvalid())
+    return ExprError();
+
+  // transform the designators.
+  ASTOwningVector<Expr*, 4> ArrayExprs(SemaRef);
+  bool ExprChanged = false;
+  for (DesignatedInitExpr::designators_iterator D = E->designators_begin(),
+                                             DEnd = E->designators_end();
+       D != DEnd; ++D) {
+    if (D->isFieldDesignator()) {
+      Desig.AddDesignator(Designator::getField(D->getFieldName(),
+                                               D->getDotLoc(),
+                                               D->getFieldLoc()));
+      continue;
+    }
+
+    if (D->isArrayDesignator()) {
+      ExprResult Index = getDerived().TransformExpr(E->getArrayIndex(*D));
+      if (Index.isInvalid())
+        return ExprError();
+
+      Desig.AddDesignator(Designator::getArray(Index.get(),
+                                               D->getLBracketLoc()));
+
+      ExprChanged = ExprChanged || Init.get() != E->getArrayIndex(*D);
+      ArrayExprs.push_back(Index.release());
+      continue;
+    }
+
+    assert(D->isArrayRangeDesignator() && "New kind of designator?");
+    ExprResult Start
+      = getDerived().TransformExpr(E->getArrayRangeStart(*D));
+    if (Start.isInvalid())
+      return ExprError();
+
+    ExprResult End = getDerived().TransformExpr(E->getArrayRangeEnd(*D));
+    if (End.isInvalid())
+      return ExprError();
+
+    Desig.AddDesignator(Designator::getArrayRange(Start.get(),
+                                                  End.get(),
+                                                  D->getLBracketLoc(),
+                                                  D->getEllipsisLoc()));
+
+    ExprChanged = ExprChanged || Start.get() != E->getArrayRangeStart(*D) ||
+      End.get() != E->getArrayRangeEnd(*D);
+
+    ArrayExprs.push_back(Start.release());
+    ArrayExprs.push_back(End.release());
+  }
+
+  if (!getDerived().AlwaysRebuild() &&
+      Init.get() == E->getInit() &&
+      !ExprChanged)
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildDesignatedInitExpr(Desig, move_arg(ArrayExprs),
+                                                E->getEqualOrColonLoc(),
+                                                E->usesGNUSyntax(), Init.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformImplicitValueInitExpr(
+                                                     ImplicitValueInitExpr *E) {
+  TemporaryBase Rebase(*this, E->getLocStart(), DeclarationName());
+  
+  // FIXME: Will we ever have proper type location here? Will we actually
+  // need to transform the type?
+  QualType T = getDerived().TransformType(E->getType());
+  if (T.isNull())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      T == E->getType())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildImplicitValueInitExpr(T);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformVAArgExpr(VAArgExpr *E) {
+  TypeSourceInfo *TInfo = getDerived().TransformType(E->getWrittenTypeInfo());
+  if (!TInfo)
+    return ExprError();
+
+  ExprResult SubExpr = getDerived().TransformExpr(E->getSubExpr());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      TInfo == E->getWrittenTypeInfo() &&
+      SubExpr.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildVAArgExpr(E->getBuiltinLoc(), SubExpr.get(),
+                                       TInfo, E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformParenListExpr(ParenListExpr *E) {
+  bool ArgumentChanged = false;
+  ASTOwningVector<Expr*, 4> Inits(SemaRef);
+  if (TransformExprs(E->getExprs(), E->getNumExprs(), true, Inits,
+                     &ArgumentChanged))
+    return ExprError();
+  
+  return getDerived().RebuildParenListExpr(E->getLParenLoc(),
+                                           move_arg(Inits),
+                                           E->getRParenLoc());
+}
+
+/// \brief Transform an address-of-label expression.
+///
+/// By default, the transformation of an address-of-label expression always
+/// rebuilds the expression, so that the label identifier can be resolved to
+/// the corresponding label statement by semantic analysis.
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformAddrLabelExpr(AddrLabelExpr *E) {
+  Decl *LD = getDerived().TransformDecl(E->getLabel()->getLocation(),
+                                        E->getLabel());
+  if (!LD)
+    return ExprError();
+  
+  return getDerived().RebuildAddrLabelExpr(E->getAmpAmpLoc(), E->getLabelLoc(),
+                                           cast<LabelDecl>(LD));
+}
+
+template<typename Derived>
+ExprResult 
+TreeTransform<Derived>::TransformStmtExpr(StmtExpr *E) {
+  SemaRef.ActOnStartStmtExpr();
+  StmtResult SubStmt
+    = getDerived().TransformCompoundStmt(E->getSubStmt(), true);
+  if (SubStmt.isInvalid()) {
+    SemaRef.ActOnStmtExprError();
+    return ExprError();
+  }
+
+  if (!getDerived().AlwaysRebuild() &&
+      SubStmt.get() == E->getSubStmt()) {
+    // Calling this an 'error' is unintuitive, but it does the right thing.
+    SemaRef.ActOnStmtExprError();
+    return SemaRef.MaybeBindToTemporary(E);
+  }
+
+  return getDerived().RebuildStmtExpr(E->getLParenLoc(),
+                                      SubStmt.get(),
+                                      E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformChooseExpr(ChooseExpr *E) {
+  ExprResult Cond = getDerived().TransformExpr(E->getCond());
+  if (Cond.isInvalid())
+    return ExprError();
+
+  ExprResult LHS = getDerived().TransformExpr(E->getLHS());
+  if (LHS.isInvalid())
+    return ExprError();
+
+  ExprResult RHS = getDerived().TransformExpr(E->getRHS());
+  if (RHS.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Cond.get() == E->getCond() &&
+      LHS.get() == E->getLHS() &&
+      RHS.get() == E->getRHS())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildChooseExpr(E->getBuiltinLoc(),
+                                        Cond.get(), LHS.get(), RHS.get(),
+                                        E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformGNUNullExpr(GNUNullExpr *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
+  switch (E->getOperator()) {
+  case OO_New:
+  case OO_Delete:
+  case OO_Array_New:
+  case OO_Array_Delete:
+    llvm_unreachable("new and delete operators cannot use CXXOperatorCallExpr");
+    
+  case OO_Call: {
+    // This is a call to an object's operator().
+    assert(E->getNumArgs() >= 1 && "Object call is missing arguments");
+
+    // Transform the object itself.
+    ExprResult Object = getDerived().TransformExpr(E->getArg(0));
+    if (Object.isInvalid())
+      return ExprError();
+
+    // FIXME: Poor location information
+    SourceLocation FakeLParenLoc
+      = SemaRef.PP.getLocForEndOfToken(
+                              static_cast<Expr *>(Object.get())->getLocEnd());
+
+    // Transform the call arguments.
+    ASTOwningVector<Expr*> Args(SemaRef);
+    if (getDerived().TransformExprs(E->getArgs() + 1, E->getNumArgs() - 1, true, 
+                                    Args))
+      return ExprError();
+
+    return getDerived().RebuildCallExpr(Object.get(), FakeLParenLoc,
+                                        move_arg(Args),
+                                        E->getLocEnd());
+  }
+
+#define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
+  case OO_##Name:
+#define OVERLOADED_OPERATOR_MULTI(Name,Spelling,Unary,Binary,MemberOnly)
+#include "clang/Basic/OperatorKinds.def"
+  case OO_Subscript:
+    // Handled below.
+    break;
+
+  case OO_Conditional:
+    llvm_unreachable("conditional operator is not actually overloadable");
+
+  case OO_None:
+  case NUM_OVERLOADED_OPERATORS:
+    llvm_unreachable("not an overloaded operator?");
+  }
+
+  ExprResult Callee = getDerived().TransformExpr(E->getCallee());
+  if (Callee.isInvalid())
+    return ExprError();
+
+  ExprResult First = getDerived().TransformExpr(E->getArg(0));
+  if (First.isInvalid())
+    return ExprError();
+
+  ExprResult Second;
+  if (E->getNumArgs() == 2) {
+    Second = getDerived().TransformExpr(E->getArg(1));
+    if (Second.isInvalid())
+      return ExprError();
+  }
+
+  if (!getDerived().AlwaysRebuild() &&
+      Callee.get() == E->getCallee() &&
+      First.get() == E->getArg(0) &&
+      (E->getNumArgs() != 2 || Second.get() == E->getArg(1)))
+    return SemaRef.MaybeBindToTemporary(E);
+
+  return getDerived().RebuildCXXOperatorCallExpr(E->getOperator(),
+                                                 E->getOperatorLoc(),
+                                                 Callee.get(),
+                                                 First.get(),
+                                                 Second.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXMemberCallExpr(CXXMemberCallExpr *E) {
+  return getDerived().TransformCallExpr(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCUDAKernelCallExpr(CUDAKernelCallExpr *E) {
+  // Transform the callee.
+  ExprResult Callee = getDerived().TransformExpr(E->getCallee());
+  if (Callee.isInvalid())
+    return ExprError();
+
+  // Transform exec config.
+  ExprResult EC = getDerived().TransformCallExpr(E->getConfig());
+  if (EC.isInvalid())
+    return ExprError();
+
+  // Transform arguments.
+  bool ArgChanged = false;
+  ASTOwningVector<Expr*> Args(SemaRef);
+  if (getDerived().TransformExprs(E->getArgs(), E->getNumArgs(), true, Args, 
+                                  &ArgChanged))
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Callee.get() == E->getCallee() &&
+      !ArgChanged)
+    return SemaRef.MaybeBindToTemporary(E);
+
+  // FIXME: Wrong source location information for the '('.
+  SourceLocation FakeLParenLoc
+    = ((Expr *)Callee.get())->getSourceRange().getBegin();
+  return getDerived().RebuildCallExpr(Callee.get(), FakeLParenLoc,
+                                      move_arg(Args),
+                                      E->getRParenLoc(), EC.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXNamedCastExpr(CXXNamedCastExpr *E) {
+  TypeSourceInfo *Type = getDerived().TransformType(E->getTypeInfoAsWritten());
+  if (!Type)
+    return ExprError();
+  
+  ExprResult SubExpr
+    = getDerived().TransformExpr(E->getSubExprAsWritten());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Type == E->getTypeInfoAsWritten() &&
+      SubExpr.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  // FIXME: Poor source location information here.
+  SourceLocation FakeLAngleLoc
+    = SemaRef.PP.getLocForEndOfToken(E->getOperatorLoc());
+  SourceLocation FakeRAngleLoc = E->getSubExpr()->getSourceRange().getBegin();
+  SourceLocation FakeRParenLoc
+    = SemaRef.PP.getLocForEndOfToken(
+                                  E->getSubExpr()->getSourceRange().getEnd());
+  return getDerived().RebuildCXXNamedCastExpr(E->getOperatorLoc(),
+                                              E->getStmtClass(),
+                                              FakeLAngleLoc,
+                                              Type,
+                                              FakeRAngleLoc,
+                                              FakeRAngleLoc,
+                                              SubExpr.get(),
+                                              FakeRParenLoc);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXStaticCastExpr(CXXStaticCastExpr *E) {
+  return getDerived().TransformCXXNamedCastExpr(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXDynamicCastExpr(CXXDynamicCastExpr *E) {
+  return getDerived().TransformCXXNamedCastExpr(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXReinterpretCastExpr(
+                                                      CXXReinterpretCastExpr *E) {
+  return getDerived().TransformCXXNamedCastExpr(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXConstCastExpr(CXXConstCastExpr *E) {
+  return getDerived().TransformCXXNamedCastExpr(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXFunctionalCastExpr(
+                                                     CXXFunctionalCastExpr *E) {
+  TypeSourceInfo *Type = getDerived().TransformType(E->getTypeInfoAsWritten());
+  if (!Type)
+    return ExprError();
+
+  ExprResult SubExpr
+    = getDerived().TransformExpr(E->getSubExprAsWritten());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Type == E->getTypeInfoAsWritten() &&
+      SubExpr.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCXXFunctionalCastExpr(Type,
+                                      /*FIXME:*/E->getSubExpr()->getLocStart(),
+                                                   SubExpr.get(),
+                                                   E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXTypeidExpr(CXXTypeidExpr *E) {
+  if (E->isTypeOperand()) {
+    TypeSourceInfo *TInfo
+      = getDerived().TransformType(E->getTypeOperandSourceInfo());
+    if (!TInfo)
+      return ExprError();
+
+    if (!getDerived().AlwaysRebuild() &&
+        TInfo == E->getTypeOperandSourceInfo())
+      return SemaRef.Owned(E);
+
+    return getDerived().RebuildCXXTypeidExpr(E->getType(),
+                                             E->getLocStart(),
+                                             TInfo,
+                                             E->getLocEnd());
+  }
+
+  // We don't know whether the subexpression is potentially evaluated until
+  // after we perform semantic analysis.  We speculatively assume it is
+  // unevaluated; it will get fixed later if the subexpression is in fact
+  // potentially evaluated.
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+
+  ExprResult SubExpr = getDerived().TransformExpr(E->getExprOperand());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      SubExpr.get() == E->getExprOperand())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCXXTypeidExpr(E->getType(),
+                                           E->getLocStart(),
+                                           SubExpr.get(),
+                                           E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXUuidofExpr(CXXUuidofExpr *E) {
+  if (E->isTypeOperand()) {
+    TypeSourceInfo *TInfo
+      = getDerived().TransformType(E->getTypeOperandSourceInfo());
+    if (!TInfo)
+      return ExprError();
+
+    if (!getDerived().AlwaysRebuild() &&
+        TInfo == E->getTypeOperandSourceInfo())
+      return SemaRef.Owned(E);
+
+    return getDerived().RebuildCXXUuidofExpr(E->getType(),
+                                             E->getLocStart(),
+                                             TInfo,
+                                             E->getLocEnd());
+  }
+
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+
+  ExprResult SubExpr = getDerived().TransformExpr(E->getExprOperand());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      SubExpr.get() == E->getExprOperand())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCXXUuidofExpr(E->getType(),
+                                           E->getLocStart(),
+                                           SubExpr.get(),
+                                           E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXNullPtrLiteralExpr(
+                                                     CXXNullPtrLiteralExpr *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXThisExpr(CXXThisExpr *E) {
+  DeclContext *DC = getSema().getFunctionLevelDeclContext();
+  QualType T;
+  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(DC))
+    T = MD->getThisType(getSema().Context);
+  else
+    T = getSema().Context.getPointerType(
+      getSema().Context.getRecordType(cast<CXXRecordDecl>(DC)));
+
+  if (!getDerived().AlwaysRebuild() && T == E->getType()) {
+    // Make sure that we capture 'this'.
+    getSema().CheckCXXThisCapture(E->getLocStart());
+    return SemaRef.Owned(E);
+  }
+  
+  return getDerived().RebuildCXXThisExpr(E->getLocStart(), T, E->isImplicit());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXThrowExpr(CXXThrowExpr *E) {
+  ExprResult SubExpr = getDerived().TransformExpr(E->getSubExpr());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      SubExpr.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCXXThrowExpr(E->getThrowLoc(), SubExpr.get(),
+                                          E->isThrownVariableInScope());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXDefaultArgExpr(CXXDefaultArgExpr *E) {
+  ParmVarDecl *Param
+    = cast_or_null<ParmVarDecl>(getDerived().TransformDecl(E->getLocStart(),
+                                                           E->getParam()));
+  if (!Param)
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      Param == E->getParam())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCXXDefaultArgExpr(E->getUsedLocation(), Param);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXScalarValueInitExpr(
+                                                    CXXScalarValueInitExpr *E) {
+  TypeSourceInfo *T = getDerived().TransformType(E->getTypeSourceInfo());
+  if (!T)
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() &&
+      T == E->getTypeSourceInfo())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCXXScalarValueInitExpr(T, 
+                                          /*FIXME:*/T->getTypeLoc().getEndLoc(),
+                                                    E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXNewExpr(CXXNewExpr *E) {
+  // Transform the type that we're allocating
+  TypeSourceInfo *AllocTypeInfo
+    = getDerived().TransformType(E->getAllocatedTypeSourceInfo());
+  if (!AllocTypeInfo)
+    return ExprError();
+
+  // Transform the size of the array we're allocating (if any).
+  ExprResult ArraySize = getDerived().TransformExpr(E->getArraySize());
+  if (ArraySize.isInvalid())
+    return ExprError();
+
+  // Transform the placement arguments (if any).
+  bool ArgumentChanged = false;
+  ASTOwningVector<Expr*> PlacementArgs(SemaRef);
+  if (getDerived().TransformExprs(E->getPlacementArgs(), 
+                                  E->getNumPlacementArgs(), true,
+                                  PlacementArgs, &ArgumentChanged))
+    return ExprError();
+
+  // Transform the initializer (if any).
+  Expr *OldInit = E->getInitializer();
+  ExprResult NewInit;
+  if (OldInit)
+    NewInit = getDerived().TransformExpr(OldInit);
+  if (NewInit.isInvalid())
+    return ExprError();
+
+  // Transform new operator and delete operator.
+  FunctionDecl *OperatorNew = 0;
+  if (E->getOperatorNew()) {
+    OperatorNew = cast_or_null<FunctionDecl>(
+                                 getDerived().TransformDecl(E->getLocStart(),
+                                                         E->getOperatorNew()));
+    if (!OperatorNew)
+      return ExprError();
+  }
+
+  FunctionDecl *OperatorDelete = 0;
+  if (E->getOperatorDelete()) {
+    OperatorDelete = cast_or_null<FunctionDecl>(
+                                   getDerived().TransformDecl(E->getLocStart(),
+                                                       E->getOperatorDelete()));
+    if (!OperatorDelete)
+      return ExprError();
+  }
+  
+  if (!getDerived().AlwaysRebuild() &&
+      AllocTypeInfo == E->getAllocatedTypeSourceInfo() &&
+      ArraySize.get() == E->getArraySize() &&
+      NewInit.get() == OldInit &&
+      OperatorNew == E->getOperatorNew() &&
+      OperatorDelete == E->getOperatorDelete() &&
+      !ArgumentChanged) {
+    // Mark any declarations we need as referenced.
+    // FIXME: instantiation-specific.
+    if (OperatorNew)
+      SemaRef.MarkFunctionReferenced(E->getLocStart(), OperatorNew);
+    if (OperatorDelete)
+      SemaRef.MarkFunctionReferenced(E->getLocStart(), OperatorDelete);
+    
+    if (E->isArray() && !E->getAllocatedType()->isDependentType()) {
+      QualType ElementType
+        = SemaRef.Context.getBaseElementType(E->getAllocatedType());
+      if (const RecordType *RecordT = ElementType->getAs<RecordType>()) {
+        CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordT->getDecl());
+        if (CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(Record)) {
+          SemaRef.MarkFunctionReferenced(E->getLocStart(), Destructor);
+        }
+      }
+    }
+
+    return SemaRef.Owned(E);
+  }
+
+  QualType AllocType = AllocTypeInfo->getType();
+  if (!ArraySize.get()) {
+    // If no array size was specified, but the new expression was
+    // instantiated with an array type (e.g., "new T" where T is
+    // instantiated with "int[4]"), extract the outer bound from the
+    // array type as our array size. We do this with constant and
+    // dependently-sized array types.
+    const ArrayType *ArrayT = SemaRef.Context.getAsArrayType(AllocType);
+    if (!ArrayT) {
+      // Do nothing
+    } else if (const ConstantArrayType *ConsArrayT
+                                     = dyn_cast<ConstantArrayType>(ArrayT)) {
+      ArraySize 
+        = SemaRef.Owned(IntegerLiteral::Create(SemaRef.Context,
+                                               ConsArrayT->getSize(), 
+                                               SemaRef.Context.getSizeType(),
+                                               /*FIXME:*/E->getLocStart()));
+      AllocType = ConsArrayT->getElementType();
+    } else if (const DependentSizedArrayType *DepArrayT
+                              = dyn_cast<DependentSizedArrayType>(ArrayT)) {
+      if (DepArrayT->getSizeExpr()) {
+        ArraySize = SemaRef.Owned(DepArrayT->getSizeExpr());
+        AllocType = DepArrayT->getElementType();
+      }
+    }
+  }
+
+  return getDerived().RebuildCXXNewExpr(E->getLocStart(),
+                                        E->isGlobalNew(),
+                                        /*FIXME:*/E->getLocStart(),
+                                        move_arg(PlacementArgs),
+                                        /*FIXME:*/E->getLocStart(),
+                                        E->getTypeIdParens(),
+                                        AllocType,
+                                        AllocTypeInfo,
+                                        ArraySize.get(),
+                                        E->getDirectInitRange(),
+                                        NewInit.take());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXDeleteExpr(CXXDeleteExpr *E) {
+  ExprResult Operand = getDerived().TransformExpr(E->getArgument());
+  if (Operand.isInvalid())
+    return ExprError();
+
+  // Transform the delete operator, if known.
+  FunctionDecl *OperatorDelete = 0;
+  if (E->getOperatorDelete()) {
+    OperatorDelete = cast_or_null<FunctionDecl>(
+                                   getDerived().TransformDecl(E->getLocStart(),
+                                                       E->getOperatorDelete()));
+    if (!OperatorDelete)
+      return ExprError();
+  }
+  
+  if (!getDerived().AlwaysRebuild() &&
+      Operand.get() == E->getArgument() &&
+      OperatorDelete == E->getOperatorDelete()) {
+    // Mark any declarations we need as referenced.
+    // FIXME: instantiation-specific.
+    if (OperatorDelete)
+      SemaRef.MarkFunctionReferenced(E->getLocStart(), OperatorDelete);
+    
+    if (!E->getArgument()->isTypeDependent()) {
+      QualType Destroyed = SemaRef.Context.getBaseElementType(
+                                                         E->getDestroyedType());
+      if (const RecordType *DestroyedRec = Destroyed->getAs<RecordType>()) {
+        CXXRecordDecl *Record = cast<CXXRecordDecl>(DestroyedRec->getDecl());
+        SemaRef.MarkFunctionReferenced(E->getLocStart(), 
+                                       SemaRef.LookupDestructor(Record));
+      }
+    }
+    
+    return SemaRef.Owned(E);
+  }
+
+  return getDerived().RebuildCXXDeleteExpr(E->getLocStart(),
+                                           E->isGlobalDelete(),
+                                           E->isArrayForm(),
+                                           Operand.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXPseudoDestructorExpr(
+                                                     CXXPseudoDestructorExpr *E) {
+  ExprResult Base = getDerived().TransformExpr(E->getBase());
+  if (Base.isInvalid())
+    return ExprError();
+
+  ParsedType ObjectTypePtr;
+  bool MayBePseudoDestructor = false;
+  Base = SemaRef.ActOnStartCXXMemberReference(0, Base.get(), 
+                                              E->getOperatorLoc(),
+                                        E->isArrow()? tok::arrow : tok::period,
+                                              ObjectTypePtr,
+                                              MayBePseudoDestructor);
+  if (Base.isInvalid())
+    return ExprError();
+                                              
+  QualType ObjectType = ObjectTypePtr.get();
+  NestedNameSpecifierLoc QualifierLoc = E->getQualifierLoc();
+  if (QualifierLoc) {
+    QualifierLoc
+      = getDerived().TransformNestedNameSpecifierLoc(QualifierLoc, ObjectType);
+    if (!QualifierLoc)
+      return ExprError();
+  }
+  CXXScopeSpec SS;
+  SS.Adopt(QualifierLoc);
+
+  PseudoDestructorTypeStorage Destroyed;
+  if (E->getDestroyedTypeInfo()) {
+    TypeSourceInfo *DestroyedTypeInfo
+      = getDerived().TransformTypeInObjectScope(E->getDestroyedTypeInfo(),
+                                                ObjectType, 0, SS);
+    if (!DestroyedTypeInfo)
+      return ExprError();
+    Destroyed = DestroyedTypeInfo;
+  } else if (!ObjectType.isNull() && ObjectType->isDependentType()) {
+    // We aren't likely to be able to resolve the identifier down to a type
+    // now anyway, so just retain the identifier.
+    Destroyed = PseudoDestructorTypeStorage(E->getDestroyedTypeIdentifier(),
+                                            E->getDestroyedTypeLoc());
+  } else {
+    // Look for a destructor known with the given name.
+    ParsedType T = SemaRef.getDestructorName(E->getTildeLoc(),
+                                              *E->getDestroyedTypeIdentifier(),
+                                                E->getDestroyedTypeLoc(),
+                                                /*Scope=*/0,
+                                                SS, ObjectTypePtr,
+                                                false);
+    if (!T)
+      return ExprError();
+    
+    Destroyed
+      = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.GetTypeFromParser(T),
+                                                 E->getDestroyedTypeLoc());
+  }
+
+  TypeSourceInfo *ScopeTypeInfo = 0;
+  if (E->getScopeTypeInfo()) {
+    ScopeTypeInfo = getDerived().TransformType(E->getScopeTypeInfo());
+    if (!ScopeTypeInfo)
+      return ExprError();
+  }
+  
+  return getDerived().RebuildCXXPseudoDestructorExpr(Base.get(),
+                                                     E->getOperatorLoc(),
+                                                     E->isArrow(),
+                                                     SS,
+                                                     ScopeTypeInfo,
+                                                     E->getColonColonLoc(),
+                                                     E->getTildeLoc(),
+                                                     Destroyed);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformUnresolvedLookupExpr(
+                                                  UnresolvedLookupExpr *Old) {
+  LookupResult R(SemaRef, Old->getName(), Old->getNameLoc(),
+                 Sema::LookupOrdinaryName);
+
+  // Transform all the decls.
+  for (UnresolvedLookupExpr::decls_iterator I = Old->decls_begin(),
+         E = Old->decls_end(); I != E; ++I) {
+    NamedDecl *InstD = static_cast<NamedDecl*>(
+                                 getDerived().TransformDecl(Old->getNameLoc(),
+                                                            *I));
+    if (!InstD) {
+      // Silently ignore these if a UsingShadowDecl instantiated to nothing.
+      // This can happen because of dependent hiding.
+      if (isa<UsingShadowDecl>(*I))
+        continue;
+      else
+        return ExprError();
+    }
+
+    // Expand using declarations.
+    if (isa<UsingDecl>(InstD)) {
+      UsingDecl *UD = cast<UsingDecl>(InstD);
+      for (UsingDecl::shadow_iterator I = UD->shadow_begin(),
+             E = UD->shadow_end(); I != E; ++I)
+        R.addDecl(*I);
+      continue;
+    }
+
+    R.addDecl(InstD);
+  }
+
+  // Resolve a kind, but don't do any further analysis.  If it's
+  // ambiguous, the callee needs to deal with it.
+  R.resolveKind();
+
+  // Rebuild the nested-name qualifier, if present.
+  CXXScopeSpec SS;
+  if (Old->getQualifierLoc()) {
+    NestedNameSpecifierLoc QualifierLoc
+      = getDerived().TransformNestedNameSpecifierLoc(Old->getQualifierLoc());
+    if (!QualifierLoc)
+      return ExprError();
+    
+    SS.Adopt(QualifierLoc);
+  } 
+  
+  if (Old->getNamingClass()) {
+    CXXRecordDecl *NamingClass
+      = cast_or_null<CXXRecordDecl>(getDerived().TransformDecl(
+                                                            Old->getNameLoc(),
+                                                        Old->getNamingClass()));
+    if (!NamingClass)
+      return ExprError();
+    
+    R.setNamingClass(NamingClass);
+  }
+
+  SourceLocation TemplateKWLoc = Old->getTemplateKeywordLoc();
+
+  // If we have neither explicit template arguments, nor the template keyword,
+  // it's a normal declaration name.
+  if (!Old->hasExplicitTemplateArgs() && !TemplateKWLoc.isValid())
+    return getDerived().RebuildDeclarationNameExpr(SS, R, Old->requiresADL());
+
+  // If we have template arguments, rebuild them, then rebuild the
+  // templateid expression.
+  TemplateArgumentListInfo TransArgs(Old->getLAngleLoc(), Old->getRAngleLoc());
+  if (getDerived().TransformTemplateArguments(Old->getTemplateArgs(),
+                                              Old->getNumTemplateArgs(),
+                                              TransArgs))
+    return ExprError();
+
+  return getDerived().RebuildTemplateIdExpr(SS, TemplateKWLoc, R,
+                                            Old->requiresADL(), &TransArgs);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformUnaryTypeTraitExpr(UnaryTypeTraitExpr *E) {
+  TypeSourceInfo *T = getDerived().TransformType(E->getQueriedTypeSourceInfo());
+  if (!T)
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      T == E->getQueriedTypeSourceInfo())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildUnaryTypeTrait(E->getTrait(),
+                                            E->getLocStart(),
+                                            T,
+                                            E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformBinaryTypeTraitExpr(BinaryTypeTraitExpr *E) {
+  TypeSourceInfo *LhsT = getDerived().TransformType(E->getLhsTypeSourceInfo());
+  if (!LhsT)
+    return ExprError();
+
+  TypeSourceInfo *RhsT = getDerived().TransformType(E->getRhsTypeSourceInfo());
+  if (!RhsT)
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      LhsT == E->getLhsTypeSourceInfo() && RhsT == E->getRhsTypeSourceInfo())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildBinaryTypeTrait(E->getTrait(),
+                                            E->getLocStart(),
+                                            LhsT, RhsT,
+                                            E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformTypeTraitExpr(TypeTraitExpr *E) {
+  bool ArgChanged = false;
+  llvm::SmallVector<TypeSourceInfo *, 4> Args;
+  for (unsigned I = 0, N = E->getNumArgs(); I != N; ++I) {
+    TypeSourceInfo *From = E->getArg(I);
+    TypeLoc FromTL = From->getTypeLoc();
+    if (!isa<PackExpansionTypeLoc>(FromTL)) {
+      TypeLocBuilder TLB;
+      TLB.reserve(FromTL.getFullDataSize());
+      QualType To = getDerived().TransformType(TLB, FromTL);
+      if (To.isNull())
+        return ExprError();
+      
+      if (To == From->getType())
+        Args.push_back(From);
+      else {
+        Args.push_back(TLB.getTypeSourceInfo(SemaRef.Context, To));
+        ArgChanged = true;
+      }
+      continue;
+    }
+    
+    ArgChanged = true;
+    
+    // We have a pack expansion. Instantiate it.
+    PackExpansionTypeLoc ExpansionTL = cast<PackExpansionTypeLoc>(FromTL);      
+    TypeLoc PatternTL = ExpansionTL.getPatternLoc();
+    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+    SemaRef.collectUnexpandedParameterPacks(PatternTL, Unexpanded);
+    
+    // Determine whether the set of unexpanded parameter packs can and should
+    // be expanded.
+    bool Expand = true;
+    bool RetainExpansion = false;
+    llvm::Optional<unsigned> OrigNumExpansions
+      = ExpansionTL.getTypePtr()->getNumExpansions();
+    llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
+    if (getDerived().TryExpandParameterPacks(ExpansionTL.getEllipsisLoc(),
+                                             PatternTL.getSourceRange(),
+                                             Unexpanded,
+                                             Expand, RetainExpansion,
+                                             NumExpansions))
+      return ExprError();
+    
+    if (!Expand) {
+      // The transform has determined that we should perform a simple
+      // transformation on the pack expansion, producing another pack 
+      // expansion.
+      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), -1);
+      
+      TypeLocBuilder TLB;
+      TLB.reserve(From->getTypeLoc().getFullDataSize());
+
+      QualType To = getDerived().TransformType(TLB, PatternTL);
+      if (To.isNull())
+        return ExprError();
+
+      To = getDerived().RebuildPackExpansionType(To, 
+                                                 PatternTL.getSourceRange(),
+                                                 ExpansionTL.getEllipsisLoc(),
+                                                 NumExpansions);
+      if (To.isNull())
+        return ExprError();
+      
+      PackExpansionTypeLoc ToExpansionTL
+        = TLB.push<PackExpansionTypeLoc>(To);
+      ToExpansionTL.setEllipsisLoc(ExpansionTL.getEllipsisLoc());
+      Args.push_back(TLB.getTypeSourceInfo(SemaRef.Context, To));
+      continue;
+    }
+
+    // Expand the pack expansion by substituting for each argument in the
+    // pack(s).
+    for (unsigned I = 0; I != *NumExpansions; ++I) {
+      Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, I);
+      TypeLocBuilder TLB;
+      TLB.reserve(PatternTL.getFullDataSize());
+      QualType To = getDerived().TransformType(TLB, PatternTL);
+      if (To.isNull())
+        return ExprError();
+
+      Args.push_back(TLB.getTypeSourceInfo(SemaRef.Context, To));
+    }
+    
+    if (!RetainExpansion)
+      continue;
+    
+    // If we're supposed to retain a pack expansion, do so by temporarily
+    // forgetting the partially-substituted parameter pack.
+    ForgetPartiallySubstitutedPackRAII Forget(getDerived());
+
+    TypeLocBuilder TLB;
+    TLB.reserve(From->getTypeLoc().getFullDataSize());
+    
+    QualType To = getDerived().TransformType(TLB, PatternTL);
+    if (To.isNull())
+      return ExprError();
+    
+    To = getDerived().RebuildPackExpansionType(To, 
+                                               PatternTL.getSourceRange(),
+                                               ExpansionTL.getEllipsisLoc(),
+                                               NumExpansions);
+    if (To.isNull())
+      return ExprError();
+    
+    PackExpansionTypeLoc ToExpansionTL
+      = TLB.push<PackExpansionTypeLoc>(To);
+    ToExpansionTL.setEllipsisLoc(ExpansionTL.getEllipsisLoc());
+    Args.push_back(TLB.getTypeSourceInfo(SemaRef.Context, To));
+  }
+  
+  if (!getDerived().AlwaysRebuild() && !ArgChanged)
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildTypeTrait(E->getTrait(),
+                                       E->getLocStart(),
+                                       Args,
+                                       E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformArrayTypeTraitExpr(ArrayTypeTraitExpr *E) {
+  TypeSourceInfo *T = getDerived().TransformType(E->getQueriedTypeSourceInfo());
+  if (!T)
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      T == E->getQueriedTypeSourceInfo())
+    return SemaRef.Owned(E);
+
+  ExprResult SubExpr;
+  {
+    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+    SubExpr = getDerived().TransformExpr(E->getDimensionExpression());
+    if (SubExpr.isInvalid())
+      return ExprError();
+
+    if (!getDerived().AlwaysRebuild() && SubExpr.get() == E->getDimensionExpression())
+      return SemaRef.Owned(E);
+  }
+
+  return getDerived().RebuildArrayTypeTrait(E->getTrait(),
+                                            E->getLocStart(),
+                                            T,
+                                            SubExpr.get(),
+                                            E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformExpressionTraitExpr(ExpressionTraitExpr *E) {
+  ExprResult SubExpr;
+  {
+    EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+    SubExpr = getDerived().TransformExpr(E->getQueriedExpression());
+    if (SubExpr.isInvalid())
+      return ExprError();
+
+    if (!getDerived().AlwaysRebuild() && SubExpr.get() == E->getQueriedExpression())
+      return SemaRef.Owned(E);
+  }
+
+  return getDerived().RebuildExpressionTrait(
+      E->getTrait(), E->getLocStart(), SubExpr.get(), E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformDependentScopeDeclRefExpr(
+                                               DependentScopeDeclRefExpr *E) {
+  NestedNameSpecifierLoc QualifierLoc
+  = getDerived().TransformNestedNameSpecifierLoc(E->getQualifierLoc());
+  if (!QualifierLoc)
+    return ExprError();
+  SourceLocation TemplateKWLoc = E->getTemplateKeywordLoc();
+
+  // TODO: If this is a conversion-function-id, verify that the
+  // destination type name (if present) resolves the same way after
+  // instantiation as it did in the local scope.
+
+  DeclarationNameInfo NameInfo
+    = getDerived().TransformDeclarationNameInfo(E->getNameInfo());
+  if (!NameInfo.getName())
+    return ExprError();
+
+  if (!E->hasExplicitTemplateArgs()) {
+    if (!getDerived().AlwaysRebuild() &&
+        QualifierLoc == E->getQualifierLoc() &&
+        // Note: it is sufficient to compare the Name component of NameInfo:
+        // if name has not changed, DNLoc has not changed either.
+        NameInfo.getName() == E->getDeclName())
+      return SemaRef.Owned(E);
+
+    return getDerived().RebuildDependentScopeDeclRefExpr(QualifierLoc,
+                                                         TemplateKWLoc,
+                                                         NameInfo,
+                                                         /*TemplateArgs*/ 0);
+  }
+
+  TemplateArgumentListInfo TransArgs(E->getLAngleLoc(), E->getRAngleLoc());
+  if (getDerived().TransformTemplateArguments(E->getTemplateArgs(),
+                                              E->getNumTemplateArgs(),
+                                              TransArgs))
+    return ExprError();
+
+  return getDerived().RebuildDependentScopeDeclRefExpr(QualifierLoc,
+                                                       TemplateKWLoc,
+                                                       NameInfo,
+                                                       &TransArgs);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXConstructExpr(CXXConstructExpr *E) {
+  // CXXConstructExprs are always implicit, so when we have a
+  // 1-argument construction we just transform that argument.
+  if (E->getNumArgs() == 1 ||
+      (E->getNumArgs() > 1 && getDerived().DropCallArgument(E->getArg(1))))
+    return getDerived().TransformExpr(E->getArg(0));
+
+  TemporaryBase Rebase(*this, /*FIXME*/E->getLocStart(), DeclarationName());
+
+  QualType T = getDerived().TransformType(E->getType());
+  if (T.isNull())
+    return ExprError();
+
+  CXXConstructorDecl *Constructor
+    = cast_or_null<CXXConstructorDecl>(
+                                getDerived().TransformDecl(E->getLocStart(),
+                                                         E->getConstructor()));
+  if (!Constructor)
+    return ExprError();
+
+  bool ArgumentChanged = false;
+  ASTOwningVector<Expr*> Args(SemaRef);
+  if (getDerived().TransformExprs(E->getArgs(), E->getNumArgs(), true, Args, 
+                                  &ArgumentChanged))
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() &&
+      T == E->getType() &&
+      Constructor == E->getConstructor() &&
+      !ArgumentChanged) {
+    // Mark the constructor as referenced.
+    // FIXME: Instantiation-specific
+    SemaRef.MarkFunctionReferenced(E->getLocStart(), Constructor);
+    return SemaRef.Owned(E);
+  }
+
+  return getDerived().RebuildCXXConstructExpr(T, /*FIXME:*/E->getLocStart(),
+                                              Constructor, E->isElidable(),
+                                              move_arg(Args),
+                                              E->hadMultipleCandidates(),
+                                              E->requiresZeroInitialization(),
+                                              E->getConstructionKind(),
+                                              E->getParenRange());
+}
+
+/// \brief Transform a C++ temporary-binding expression.
+///
+/// Since CXXBindTemporaryExpr nodes are implicitly generated, we just
+/// transform the subexpression and return that.
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
+  return getDerived().TransformExpr(E->getSubExpr());
+}
+
+/// \brief Transform a C++ expression that contains cleanups that should
+/// be run after the expression is evaluated.
+///
+/// Since ExprWithCleanups nodes are implicitly generated, we
+/// just transform the subexpression and return that.
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformExprWithCleanups(ExprWithCleanups *E) {
+  return getDerived().TransformExpr(E->getSubExpr());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXTemporaryObjectExpr(
+                                                    CXXTemporaryObjectExpr *E) {
+  TypeSourceInfo *T = getDerived().TransformType(E->getTypeSourceInfo());
+  if (!T)
+    return ExprError();
+
+  CXXConstructorDecl *Constructor
+    = cast_or_null<CXXConstructorDecl>(
+                                  getDerived().TransformDecl(E->getLocStart(), 
+                                                         E->getConstructor()));
+  if (!Constructor)
+    return ExprError();
+
+  bool ArgumentChanged = false;
+  ASTOwningVector<Expr*> Args(SemaRef);
+  Args.reserve(E->getNumArgs());
+  if (TransformExprs(E->getArgs(), E->getNumArgs(), true, Args, 
+                     &ArgumentChanged))
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      T == E->getTypeSourceInfo() &&
+      Constructor == E->getConstructor() &&
+      !ArgumentChanged) {
+    // FIXME: Instantiation-specific
+    SemaRef.MarkFunctionReferenced(E->getLocStart(), Constructor);
+    return SemaRef.MaybeBindToTemporary(E);
+  }
+  
+  return getDerived().RebuildCXXTemporaryObjectExpr(T,
+                                          /*FIXME:*/T->getTypeLoc().getEndLoc(),
+                                                    move_arg(Args),
+                                                    E->getLocEnd());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
+  // Create the local class that will describe the lambda.
+  CXXRecordDecl *Class
+    = getSema().createLambdaClosureType(E->getIntroducerRange(),
+                                        /*KnownDependent=*/false);
+  getDerived().transformedLocalDecl(E->getLambdaClass(), Class);
+  
+  // Transform the type of the lambda parameters and start the definition of
+  // the lambda itself.
+  TypeSourceInfo *MethodTy
+    = TransformType(E->getCallOperator()->getTypeSourceInfo());  
+  if (!MethodTy)
+    return ExprError();
+
+  // Transform lambda parameters.
+  bool Invalid = false;
+  llvm::SmallVector<QualType, 4> ParamTypes;
+  llvm::SmallVector<ParmVarDecl *, 4> Params;
+  if (getDerived().TransformFunctionTypeParams(E->getLocStart(),
+        E->getCallOperator()->param_begin(),
+        E->getCallOperator()->param_size(),
+        0, ParamTypes, &Params))
+    Invalid = true;  
+
+  // Build the call operator.
+  // Note: Once a lambda mangling number and context declaration have been
+  // assigned, they never change.
+  unsigned ManglingNumber = E->getLambdaClass()->getLambdaManglingNumber();
+  Decl *ContextDecl = E->getLambdaClass()->getLambdaContextDecl();  
+  CXXMethodDecl *CallOperator
+    = getSema().startLambdaDefinition(Class, E->getIntroducerRange(),
+                                      MethodTy, 
+                                      E->getCallOperator()->getLocEnd(),
+                                      Params, ManglingNumber, ContextDecl);
+  getDerived().transformAttrs(E->getCallOperator(), CallOperator);
+  
+  // FIXME: Instantiation-specific.
+  CallOperator->setInstantiationOfMemberFunction(E->getCallOperator(), 
+                                                 TSK_ImplicitInstantiation);
+
+  // Introduce the context of the call operator.
+  Sema::ContextRAII SavedContext(getSema(), CallOperator);
+
+  // Enter the scope of the lambda.
+  sema::LambdaScopeInfo *LSI
+    = getSema().enterLambdaScope(CallOperator, E->getIntroducerRange(),
+                                 E->getCaptureDefault(),
+                                 E->hasExplicitParameters(),
+                                 E->hasExplicitResultType(),
+                                 E->isMutable());
+  
+  // Transform captures.
+  bool FinishedExplicitCaptures = false;
+  for (LambdaExpr::capture_iterator C = E->capture_begin(), 
+                                 CEnd = E->capture_end();
+       C != CEnd; ++C) {
+    // When we hit the first implicit capture, tell Sema that we've finished
+    // the list of explicit captures.
+    if (!FinishedExplicitCaptures && C->isImplicit()) {
+      getSema().finishLambdaExplicitCaptures(LSI);
+      FinishedExplicitCaptures = true;
+    }
+    
+    // Capturing 'this' is trivial.
+    if (C->capturesThis()) {
+      getSema().CheckCXXThisCapture(C->getLocation(), C->isExplicit());
+      continue;
+    }
+    
+    // Determine the capture kind for Sema.
+    Sema::TryCaptureKind Kind
+      = C->isImplicit()? Sema::TryCapture_Implicit
+                       : C->getCaptureKind() == LCK_ByCopy
+                           ? Sema::TryCapture_ExplicitByVal
+                           : Sema::TryCapture_ExplicitByRef;
+    SourceLocation EllipsisLoc;
+    if (C->isPackExpansion()) {
+      UnexpandedParameterPack Unexpanded(C->getCapturedVar(), C->getLocation());
+      bool ShouldExpand = false;
+      bool RetainExpansion = false;
+      llvm::Optional<unsigned> NumExpansions;
+      if (getDerived().TryExpandParameterPacks(C->getEllipsisLoc(), 
+                                               C->getLocation(), 
+                                               Unexpanded,
+                                               ShouldExpand, RetainExpansion,
+                                               NumExpansions))
+        return ExprError();
+      
+      if (ShouldExpand) {
+        // The transform has determined that we should perform an expansion;
+        // transform and capture each of the arguments.
+        // expansion of the pattern. Do so.
+        VarDecl *Pack = C->getCapturedVar();
+        for (unsigned I = 0; I != *NumExpansions; ++I) {
+          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), I);
+          VarDecl *CapturedVar
+            = cast_or_null<VarDecl>(getDerived().TransformDecl(C->getLocation(), 
+                                                               Pack));
+          if (!CapturedVar) {
+            Invalid = true;
+            continue;
+          }
+          
+          // Capture the transformed variable.
+          getSema().tryCaptureVariable(CapturedVar, C->getLocation(), Kind);          
+        }          
+        continue;
+      }
+      
+      EllipsisLoc = C->getEllipsisLoc();
+    }
+    
+    // Transform the captured variable.
+    VarDecl *CapturedVar
+      = cast_or_null<VarDecl>(getDerived().TransformDecl(C->getLocation(), 
+                                                         C->getCapturedVar()));
+    if (!CapturedVar) {
+      Invalid = true;
+      continue;
+    }
+  
+    // Capture the transformed variable.
+    getSema().tryCaptureVariable(CapturedVar, C->getLocation(), Kind);
+  }
+  if (!FinishedExplicitCaptures)
+    getSema().finishLambdaExplicitCaptures(LSI);
+
+
+  // Enter a new evaluation context to insulate the lambda from any
+  // cleanups from the enclosing full-expression.
+  getSema().PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);  
+
+  if (Invalid) {
+    getSema().ActOnLambdaError(E->getLocStart(), /*CurScope=*/0, 
+                               /*IsInstantiation=*/true);
+    return ExprError();
+  }
+
+  // Instantiate the body of the lambda expression.
+  StmtResult Body = getDerived().TransformStmt(E->getBody());
+  if (Body.isInvalid()) {
+    getSema().ActOnLambdaError(E->getLocStart(), /*CurScope=*/0, 
+                               /*IsInstantiation=*/true);
+    return ExprError();    
+  }
+
+  return getSema().ActOnLambdaExpr(E->getLocStart(), Body.take(), 
+                                   /*CurScope=*/0, /*IsInstantiation=*/true);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXUnresolvedConstructExpr(
+                                                  CXXUnresolvedConstructExpr *E) {
+  TypeSourceInfo *T = getDerived().TransformType(E->getTypeSourceInfo());
+  if (!T)
+    return ExprError();
+
+  bool ArgumentChanged = false;
+  ASTOwningVector<Expr*> Args(SemaRef);
+  Args.reserve(E->arg_size());
+  if (getDerived().TransformExprs(E->arg_begin(), E->arg_size(), true, Args, 
+                                  &ArgumentChanged))
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() &&
+      T == E->getTypeSourceInfo() &&
+      !ArgumentChanged)
+    return SemaRef.Owned(E);
+
+  // FIXME: we're faking the locations of the commas
+  return getDerived().RebuildCXXUnresolvedConstructExpr(T,
+                                                        E->getLParenLoc(),
+                                                        move_arg(Args),
+                                                        E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXDependentScopeMemberExpr(
+                                             CXXDependentScopeMemberExpr *E) {
+  // Transform the base of the expression.
+  ExprResult Base((Expr*) 0);
+  Expr *OldBase;
+  QualType BaseType;
+  QualType ObjectType;
+  if (!E->isImplicitAccess()) {
+    OldBase = E->getBase();
+    Base = getDerived().TransformExpr(OldBase);
+    if (Base.isInvalid())
+      return ExprError();
+
+    // Start the member reference and compute the object's type.
+    ParsedType ObjectTy;
+    bool MayBePseudoDestructor = false;
+    Base = SemaRef.ActOnStartCXXMemberReference(0, Base.get(),
+                                                E->getOperatorLoc(),
+                                      E->isArrow()? tok::arrow : tok::period,
+                                                ObjectTy,
+                                                MayBePseudoDestructor);
+    if (Base.isInvalid())
+      return ExprError();
+
+    ObjectType = ObjectTy.get();
+    BaseType = ((Expr*) Base.get())->getType();
+  } else {
+    OldBase = 0;
+    BaseType = getDerived().TransformType(E->getBaseType());
+    ObjectType = BaseType->getAs<PointerType>()->getPointeeType();
+  }
+
+  // Transform the first part of the nested-name-specifier that qualifies
+  // the member name.
+  NamedDecl *FirstQualifierInScope
+    = getDerived().TransformFirstQualifierInScope(
+                                            E->getFirstQualifierFoundInScope(),
+                                            E->getQualifierLoc().getBeginLoc());
+
+  NestedNameSpecifierLoc QualifierLoc;
+  if (E->getQualifier()) {
+    QualifierLoc
+      = getDerived().TransformNestedNameSpecifierLoc(E->getQualifierLoc(),
+                                                     ObjectType,
+                                                     FirstQualifierInScope);
+    if (!QualifierLoc)
+      return ExprError();
+  }
+
+  SourceLocation TemplateKWLoc = E->getTemplateKeywordLoc();
+
+  // TODO: If this is a conversion-function-id, verify that the
+  // destination type name (if present) resolves the same way after
+  // instantiation as it did in the local scope.
+
+  DeclarationNameInfo NameInfo
+    = getDerived().TransformDeclarationNameInfo(E->getMemberNameInfo());
+  if (!NameInfo.getName())
+    return ExprError();
+
+  if (!E->hasExplicitTemplateArgs()) {
+    // This is a reference to a member without an explicitly-specified
+    // template argument list. Optimize for this common case.
+    if (!getDerived().AlwaysRebuild() &&
+        Base.get() == OldBase &&
+        BaseType == E->getBaseType() &&
+        QualifierLoc == E->getQualifierLoc() &&
+        NameInfo.getName() == E->getMember() &&
+        FirstQualifierInScope == E->getFirstQualifierFoundInScope())
+      return SemaRef.Owned(E);
+
+    return getDerived().RebuildCXXDependentScopeMemberExpr(Base.get(),
+                                                       BaseType,
+                                                       E->isArrow(),
+                                                       E->getOperatorLoc(),
+                                                       QualifierLoc,
+                                                       TemplateKWLoc,
+                                                       FirstQualifierInScope,
+                                                       NameInfo,
+                                                       /*TemplateArgs*/ 0);
+  }
+
+  TemplateArgumentListInfo TransArgs(E->getLAngleLoc(), E->getRAngleLoc());
+  if (getDerived().TransformTemplateArguments(E->getTemplateArgs(),
+                                              E->getNumTemplateArgs(),
+                                              TransArgs))
+    return ExprError();
+
+  return getDerived().RebuildCXXDependentScopeMemberExpr(Base.get(),
+                                                     BaseType,
+                                                     E->isArrow(),
+                                                     E->getOperatorLoc(),
+                                                     QualifierLoc,
+                                                     TemplateKWLoc,
+                                                     FirstQualifierInScope,
+                                                     NameInfo,
+                                                     &TransArgs);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformUnresolvedMemberExpr(UnresolvedMemberExpr *Old) {
+  // Transform the base of the expression.
+  ExprResult Base((Expr*) 0);
+  QualType BaseType;
+  if (!Old->isImplicitAccess()) {
+    Base = getDerived().TransformExpr(Old->getBase());
+    if (Base.isInvalid())
+      return ExprError();
+    Base = getSema().PerformMemberExprBaseConversion(Base.take(),
+                                                     Old->isArrow());
+    if (Base.isInvalid())
+      return ExprError();
+    BaseType = Base.get()->getType();
+  } else {
+    BaseType = getDerived().TransformType(Old->getBaseType());
+  }
+
+  NestedNameSpecifierLoc QualifierLoc;
+  if (Old->getQualifierLoc()) {
+    QualifierLoc
+    = getDerived().TransformNestedNameSpecifierLoc(Old->getQualifierLoc());
+    if (!QualifierLoc)
+      return ExprError();
+  }
+
+  SourceLocation TemplateKWLoc = Old->getTemplateKeywordLoc();
+
+  LookupResult R(SemaRef, Old->getMemberNameInfo(),
+                 Sema::LookupOrdinaryName);
+
+  // Transform all the decls.
+  for (UnresolvedMemberExpr::decls_iterator I = Old->decls_begin(),
+         E = Old->decls_end(); I != E; ++I) {
+    NamedDecl *InstD = static_cast<NamedDecl*>(
+                                getDerived().TransformDecl(Old->getMemberLoc(),
+                                                           *I));
+    if (!InstD) {
+      // Silently ignore these if a UsingShadowDecl instantiated to nothing.
+      // This can happen because of dependent hiding.
+      if (isa<UsingShadowDecl>(*I))
+        continue;
+      else {
+        R.clear();
+        return ExprError();
+      }
+    }
+
+    // Expand using declarations.
+    if (isa<UsingDecl>(InstD)) {
+      UsingDecl *UD = cast<UsingDecl>(InstD);
+      for (UsingDecl::shadow_iterator I = UD->shadow_begin(),
+             E = UD->shadow_end(); I != E; ++I)
+        R.addDecl(*I);
+      continue;
+    }
+
+    R.addDecl(InstD);
+  }
+
+  R.resolveKind();
+
+  // Determine the naming class.
+  if (Old->getNamingClass()) {
+    CXXRecordDecl *NamingClass 
+      = cast_or_null<CXXRecordDecl>(getDerived().TransformDecl(
+                                                          Old->getMemberLoc(),
+                                                        Old->getNamingClass()));
+    if (!NamingClass)
+      return ExprError();
+    
+    R.setNamingClass(NamingClass);
+  }
+  
+  TemplateArgumentListInfo TransArgs;
+  if (Old->hasExplicitTemplateArgs()) {
+    TransArgs.setLAngleLoc(Old->getLAngleLoc());
+    TransArgs.setRAngleLoc(Old->getRAngleLoc());
+    if (getDerived().TransformTemplateArguments(Old->getTemplateArgs(),
+                                                Old->getNumTemplateArgs(),
+                                                TransArgs))
+      return ExprError();
+  }
+
+  // FIXME: to do this check properly, we will need to preserve the
+  // first-qualifier-in-scope here, just in case we had a dependent
+  // base (and therefore couldn't do the check) and a
+  // nested-name-qualifier (and therefore could do the lookup).
+  NamedDecl *FirstQualifierInScope = 0;
+  
+  return getDerived().RebuildUnresolvedMemberExpr(Base.get(),
+                                                  BaseType,
+                                                  Old->getOperatorLoc(),
+                                                  Old->isArrow(),
+                                                  QualifierLoc,
+                                                  TemplateKWLoc,
+                                                  FirstQualifierInScope,
+                                                  R,
+                                              (Old->hasExplicitTemplateArgs()
+                                                  ? &TransArgs : 0));
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformCXXNoexceptExpr(CXXNoexceptExpr *E) {
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+  ExprResult SubExpr = getDerived().TransformExpr(E->getOperand());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() && SubExpr.get() == E->getOperand())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildCXXNoexceptExpr(E->getSourceRange(),SubExpr.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformPackExpansionExpr(PackExpansionExpr *E) {
+  ExprResult Pattern = getDerived().TransformExpr(E->getPattern());
+  if (Pattern.isInvalid())
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() && Pattern.get() == E->getPattern())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildPackExpansion(Pattern.get(), E->getEllipsisLoc(),
+                                           E->getNumExpansions());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformSizeOfPackExpr(SizeOfPackExpr *E) {
+  // If E is not value-dependent, then nothing will change when we transform it.
+  // Note: This is an instantiation-centric view.
+  if (!E->isValueDependent())
+    return SemaRef.Owned(E);
+
+  // Note: None of the implementations of TryExpandParameterPacks can ever
+  // produce a diagnostic when given only a single unexpanded parameter pack,
+  // so 
+  UnexpandedParameterPack Unexpanded(E->getPack(), E->getPackLoc());
+  bool ShouldExpand = false;
+  bool RetainExpansion = false;
+  llvm::Optional<unsigned> NumExpansions;
+  if (getDerived().TryExpandParameterPacks(E->getOperatorLoc(), E->getPackLoc(), 
+                                           Unexpanded,
+                                           ShouldExpand, RetainExpansion,
+                                           NumExpansions))
+    return ExprError();
+  
+  if (RetainExpansion)
+    return SemaRef.Owned(E);
+    
+  NamedDecl *Pack = E->getPack();
+  if (!ShouldExpand) {
+    Pack = cast_or_null<NamedDecl>(getDerived().TransformDecl(E->getPackLoc(), 
+                                                              Pack));
+    if (!Pack)
+      return ExprError();
+  }
+
+  
+  // We now know the length of the parameter pack, so build a new expression
+  // that stores that length.
+  return getDerived().RebuildSizeOfPackExpr(E->getOperatorLoc(), Pack, 
+                                            E->getPackLoc(), E->getRParenLoc(), 
+                                            NumExpansions);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformSubstNonTypeTemplateParmPackExpr(
+                                          SubstNonTypeTemplateParmPackExpr *E) {
+  // Default behavior is to do nothing with this transformation.
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformSubstNonTypeTemplateParmExpr(
+                                          SubstNonTypeTemplateParmExpr *E) {
+  // Default behavior is to do nothing with this transformation.
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformMaterializeTemporaryExpr(
+                                                  MaterializeTemporaryExpr *E) {
+  return getDerived().TransformExpr(E->GetTemporaryExpr());
+}
+  
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCStringLiteral(ObjCStringLiteral *E) {
+  return SemaRef.MaybeBindToTemporary(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCBoolLiteralExpr(ObjCBoolLiteralExpr *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCNumericLiteral(ObjCNumericLiteral *E) {
+  return SemaRef.MaybeBindToTemporary(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCArrayLiteral(ObjCArrayLiteral *E) {
+  // Transform each of the elements.
+  llvm::SmallVector<Expr *, 8> Elements;
+  bool ArgChanged = false;
+  if (getDerived().TransformExprs(E->getElements(), E->getNumElements(), 
+                                  /*IsCall=*/false, Elements, &ArgChanged))
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() && !ArgChanged)
+    return SemaRef.MaybeBindToTemporary(E);
+  
+  return getDerived().RebuildObjCArrayLiteral(E->getSourceRange(),
+                                              Elements.data(),
+                                              Elements.size());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCDictionaryLiteral(
+                                                    ObjCDictionaryLiteral *E) {  
+  // Transform each of the elements.
+  llvm::SmallVector<ObjCDictionaryElement, 8> Elements;
+  bool ArgChanged = false;
+  for (unsigned I = 0, N = E->getNumElements(); I != N; ++I) {
+    ObjCDictionaryElement OrigElement = E->getKeyValueElement(I);
+    
+    if (OrigElement.isPackExpansion()) {
+      // This key/value element is a pack expansion.
+      SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+      getSema().collectUnexpandedParameterPacks(OrigElement.Key, Unexpanded);
+      getSema().collectUnexpandedParameterPacks(OrigElement.Value, Unexpanded);
+      assert(!Unexpanded.empty() && "Pack expansion without parameter packs?");
+
+      // Determine whether the set of unexpanded parameter packs can
+      // and should be expanded.
+      bool Expand = true;
+      bool RetainExpansion = false;
+      llvm::Optional<unsigned> OrigNumExpansions = OrigElement.NumExpansions;
+      llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
+      SourceRange PatternRange(OrigElement.Key->getLocStart(),
+                               OrigElement.Value->getLocEnd());
+     if (getDerived().TryExpandParameterPacks(OrigElement.EllipsisLoc,
+                                               PatternRange,
+                                               Unexpanded,
+                                               Expand, RetainExpansion,
+                                               NumExpansions))
+        return ExprError();
+
+      if (!Expand) {
+        // The transform has determined that we should perform a simple
+        // transformation on the pack expansion, producing another pack 
+        // expansion.
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), -1);
+        ExprResult Key = getDerived().TransformExpr(OrigElement.Key);
+        if (Key.isInvalid())
+          return ExprError();
+
+        if (Key.get() != OrigElement.Key)
+          ArgChanged = true;
+
+        ExprResult Value = getDerived().TransformExpr(OrigElement.Value);
+        if (Value.isInvalid())
+          return ExprError();
+        
+        if (Value.get() != OrigElement.Value)
+          ArgChanged = true;
+
+        ObjCDictionaryElement Expansion = { 
+          Key.get(), Value.get(), OrigElement.EllipsisLoc, NumExpansions
+        };
+        Elements.push_back(Expansion);
+        continue;
+      }
+
+      // Record right away that the argument was changed.  This needs
+      // to happen even if the array expands to nothing.
+      ArgChanged = true;
+      
+      // The transform has determined that we should perform an elementwise
+      // expansion of the pattern. Do so.
+      for (unsigned I = 0; I != *NumExpansions; ++I) {
+        Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), I);
+        ExprResult Key = getDerived().TransformExpr(OrigElement.Key);
+        if (Key.isInvalid())
+          return ExprError();
+
+        ExprResult Value = getDerived().TransformExpr(OrigElement.Value);
+        if (Value.isInvalid())
+          return ExprError();
+
+        ObjCDictionaryElement Element = { 
+          Key.get(), Value.get(), SourceLocation(), NumExpansions
+        };
+
+        // If any unexpanded parameter packs remain, we still have a
+        // pack expansion.
+        if (Key.get()->containsUnexpandedParameterPack() ||
+            Value.get()->containsUnexpandedParameterPack())
+          Element.EllipsisLoc = OrigElement.EllipsisLoc;
+          
+        Elements.push_back(Element);
+      }
+
+      // We've finished with this pack expansion.
+      continue;
+    }
+
+    // Transform and check key.
+    ExprResult Key = getDerived().TransformExpr(OrigElement.Key);
+    if (Key.isInvalid())
+      return ExprError();
+    
+    if (Key.get() != OrigElement.Key)
+      ArgChanged = true;
+    
+    // Transform and check value.
+    ExprResult Value
+      = getDerived().TransformExpr(OrigElement.Value);
+    if (Value.isInvalid())
+      return ExprError();
+    
+    if (Value.get() != OrigElement.Value)
+      ArgChanged = true;
+    
+    ObjCDictionaryElement Element = { 
+      Key.get(), Value.get(), SourceLocation(), llvm::Optional<unsigned>()
+    };
+    Elements.push_back(Element);
+  }
+  
+  if (!getDerived().AlwaysRebuild() && !ArgChanged)
+    return SemaRef.MaybeBindToTemporary(E);
+
+  return getDerived().RebuildObjCDictionaryLiteral(E->getSourceRange(),
+                                                   Elements.data(),
+                                                   Elements.size());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCEncodeExpr(ObjCEncodeExpr *E) {
+  TypeSourceInfo *EncodedTypeInfo
+    = getDerived().TransformType(E->getEncodedTypeSourceInfo());
+  if (!EncodedTypeInfo)
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      EncodedTypeInfo == E->getEncodedTypeSourceInfo())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildObjCEncodeExpr(E->getAtLoc(),
+                                            EncodedTypeInfo,
+                                            E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult TreeTransform<Derived>::
+TransformObjCIndirectCopyRestoreExpr(ObjCIndirectCopyRestoreExpr *E) {
+  ExprResult result = getDerived().TransformExpr(E->getSubExpr());
+  if (result.isInvalid()) return ExprError();
+  Expr *subExpr = result.take();
+
+  if (!getDerived().AlwaysRebuild() &&
+      subExpr == E->getSubExpr())
+    return SemaRef.Owned(E);
+
+  return SemaRef.Owned(new(SemaRef.Context)
+      ObjCIndirectCopyRestoreExpr(subExpr, E->getType(), E->shouldCopy()));
+}
+
+template<typename Derived>
+ExprResult TreeTransform<Derived>::
+TransformObjCBridgedCastExpr(ObjCBridgedCastExpr *E) {
+  TypeSourceInfo *TSInfo 
+    = getDerived().TransformType(E->getTypeInfoAsWritten());
+  if (!TSInfo)
+    return ExprError();
+  
+  ExprResult Result = getDerived().TransformExpr(E->getSubExpr());
+  if (Result.isInvalid()) 
+    return ExprError();
+  
+  if (!getDerived().AlwaysRebuild() &&
+      TSInfo == E->getTypeInfoAsWritten() &&
+      Result.get() == E->getSubExpr())
+    return SemaRef.Owned(E);
+  
+  return SemaRef.BuildObjCBridgedCast(E->getLParenLoc(), E->getBridgeKind(),
+                                      E->getBridgeKeywordLoc(), TSInfo, 
+                                      Result.get());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCMessageExpr(ObjCMessageExpr *E) {
+  // Transform arguments.
+  bool ArgChanged = false;
+  ASTOwningVector<Expr*> Args(SemaRef);
+  Args.reserve(E->getNumArgs());
+  if (getDerived().TransformExprs(E->getArgs(), E->getNumArgs(), false, Args, 
+                                  &ArgChanged))
+    return ExprError();
+  
+  if (E->getReceiverKind() == ObjCMessageExpr::Class) {
+    // Class message: transform the receiver type.
+    TypeSourceInfo *ReceiverTypeInfo
+      = getDerived().TransformType(E->getClassReceiverTypeInfo());
+    if (!ReceiverTypeInfo)
+      return ExprError();
+    
+    // If nothing changed, just retain the existing message send.
+    if (!getDerived().AlwaysRebuild() &&
+        ReceiverTypeInfo == E->getClassReceiverTypeInfo() && !ArgChanged)
+      return SemaRef.MaybeBindToTemporary(E);
+
+    // Build a new class message send.
+    SmallVector<SourceLocation, 16> SelLocs;
+    E->getSelectorLocs(SelLocs);
+    return getDerived().RebuildObjCMessageExpr(ReceiverTypeInfo,
+                                               E->getSelector(),
+                                               SelLocs,
+                                               E->getMethodDecl(),
+                                               E->getLeftLoc(),
+                                               move_arg(Args),
+                                               E->getRightLoc());
+  }
+
+  // Instance message: transform the receiver
+  assert(E->getReceiverKind() == ObjCMessageExpr::Instance &&
+         "Only class and instance messages may be instantiated");
+  ExprResult Receiver
+    = getDerived().TransformExpr(E->getInstanceReceiver());
+  if (Receiver.isInvalid())
+    return ExprError();
+
+  // If nothing changed, just retain the existing message send.
+  if (!getDerived().AlwaysRebuild() &&
+      Receiver.get() == E->getInstanceReceiver() && !ArgChanged)
+    return SemaRef.MaybeBindToTemporary(E);
+  
+  // Build a new instance message send.
+  SmallVector<SourceLocation, 16> SelLocs;
+  E->getSelectorLocs(SelLocs);
+  return getDerived().RebuildObjCMessageExpr(Receiver.get(),
+                                             E->getSelector(),
+                                             SelLocs,
+                                             E->getMethodDecl(),
+                                             E->getLeftLoc(),
+                                             move_arg(Args),
+                                             E->getRightLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCSelectorExpr(ObjCSelectorExpr *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCProtocolExpr(ObjCProtocolExpr *E) {
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCIvarRefExpr(ObjCIvarRefExpr *E) {
+  // Transform the base expression.
+  ExprResult Base = getDerived().TransformExpr(E->getBase());
+  if (Base.isInvalid())
+    return ExprError();
+
+  // We don't need to transform the ivar; it will never change.
+  
+  // If nothing changed, just retain the existing expression.
+  if (!getDerived().AlwaysRebuild() &&
+      Base.get() == E->getBase())
+    return SemaRef.Owned(E);
+  
+  return getDerived().RebuildObjCIvarRefExpr(Base.get(), E->getDecl(),
+                                             E->getLocation(),
+                                             E->isArrow(), E->isFreeIvar());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCPropertyRefExpr(ObjCPropertyRefExpr *E) {
+  // 'super' and types never change. Property never changes. Just
+  // retain the existing expression.
+  if (!E->isObjectReceiver())
+    return SemaRef.Owned(E);
+  
+  // Transform the base expression.
+  ExprResult Base = getDerived().TransformExpr(E->getBase());
+  if (Base.isInvalid())
+    return ExprError();
+  
+  // We don't need to transform the property; it will never change.
+  
+  // If nothing changed, just retain the existing expression.
+  if (!getDerived().AlwaysRebuild() &&
+      Base.get() == E->getBase())
+    return SemaRef.Owned(E);
+
+  if (E->isExplicitProperty())
+    return getDerived().RebuildObjCPropertyRefExpr(Base.get(),
+                                                   E->getExplicitProperty(),
+                                                   E->getLocation());
+
+  return getDerived().RebuildObjCPropertyRefExpr(Base.get(),
+                                                 SemaRef.Context.PseudoObjectTy,
+                                                 E->getImplicitPropertyGetter(),
+                                                 E->getImplicitPropertySetter(),
+                                                 E->getLocation());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCSubscriptRefExpr(ObjCSubscriptRefExpr *E) {
+  // Transform the base expression.
+  ExprResult Base = getDerived().TransformExpr(E->getBaseExpr());
+  if (Base.isInvalid())
+    return ExprError();
+
+  // Transform the key expression.
+  ExprResult Key = getDerived().TransformExpr(E->getKeyExpr());
+  if (Key.isInvalid())
+    return ExprError();
+
+  // If nothing changed, just retain the existing expression.
+  if (!getDerived().AlwaysRebuild() &&
+      Key.get() == E->getKeyExpr() && Base.get() == E->getBaseExpr())
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildObjCSubscriptRefExpr(E->getRBracket(), 
+                                                  Base.get(), Key.get(),
+                                                  E->getAtIndexMethodDecl(),
+                                                  E->setAtIndexMethodDecl());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformObjCIsaExpr(ObjCIsaExpr *E) {
+  // Transform the base expression.
+  ExprResult Base = getDerived().TransformExpr(E->getBase());
+  if (Base.isInvalid())
+    return ExprError();
+  
+  // If nothing changed, just retain the existing expression.
+  if (!getDerived().AlwaysRebuild() &&
+      Base.get() == E->getBase())
+    return SemaRef.Owned(E);
+  
+  return getDerived().RebuildObjCIsaExpr(Base.get(), E->getIsaMemberLoc(),
+                                         E->isArrow());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformShuffleVectorExpr(ShuffleVectorExpr *E) {
+  bool ArgumentChanged = false;
+  ASTOwningVector<Expr*> SubExprs(SemaRef);
+  SubExprs.reserve(E->getNumSubExprs());
+  if (getDerived().TransformExprs(E->getSubExprs(), E->getNumSubExprs(), false, 
+                                  SubExprs, &ArgumentChanged))
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      !ArgumentChanged)
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildShuffleVectorExpr(E->getBuiltinLoc(),
+                                               move_arg(SubExprs),
+                                               E->getRParenLoc());
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformBlockExpr(BlockExpr *E) {
+  BlockDecl *oldBlock = E->getBlockDecl();
+  
+  SemaRef.ActOnBlockStart(E->getCaretLocation(), /*Scope=*/0);
+  BlockScopeInfo *blockScope = SemaRef.getCurBlock();
+
+  blockScope->TheDecl->setIsVariadic(oldBlock->isVariadic());
+  blockScope->TheDecl->setBlockMissingReturnType(
+                         oldBlock->blockMissingReturnType());
+  
+  SmallVector<ParmVarDecl*, 4> params;
+  SmallVector<QualType, 4> paramTypes;
+  
+  // Parameter substitution.
+  if (getDerived().TransformFunctionTypeParams(E->getCaretLocation(),
+                                               oldBlock->param_begin(),
+                                               oldBlock->param_size(),
+                                               0, paramTypes, &params)) {
+    getSema().ActOnBlockError(E->getCaretLocation(), /*Scope=*/0);
+    return ExprError();
+  }
+
+  const FunctionType *exprFunctionType = E->getFunctionType();
+  QualType exprResultType =
+      getDerived().TransformType(exprFunctionType->getResultType());
+
+  // Don't allow returning a objc interface by value.
+  if (exprResultType->isObjCObjectType()) {
+    getSema().Diag(E->getCaretLocation(), 
+                   diag::err_object_cannot_be_passed_returned_by_value) 
+      << 0 << exprResultType;
+    getSema().ActOnBlockError(E->getCaretLocation(), /*Scope=*/0);
+    return ExprError();
+  }
+
+  QualType functionType = getDerived().RebuildFunctionProtoType(
+                                                        exprResultType,
+                                                        paramTypes.data(),
+                                                        paramTypes.size(),
+                                                        oldBlock->isVariadic(),
+                                                        false, 0, RQ_None,
+                                               exprFunctionType->getExtInfo());
+  blockScope->FunctionType = functionType;
+
+  // Set the parameters on the block decl.
+  if (!params.empty())
+    blockScope->TheDecl->setParams(params);
+
+  if (!oldBlock->blockMissingReturnType()) {
+    blockScope->HasImplicitReturnType = false;
+    blockScope->ReturnType = exprResultType;
+  }
+  
+  // Transform the body
+  StmtResult body = getDerived().TransformStmt(E->getBody());
+  if (body.isInvalid()) {
+    getSema().ActOnBlockError(E->getCaretLocation(), /*Scope=*/0);
+    return ExprError();
+  }
+
+#ifndef NDEBUG
+  // In builds with assertions, make sure that we captured everything we
+  // captured before.
+  if (!SemaRef.getDiagnostics().hasErrorOccurred()) {
+    for (BlockDecl::capture_iterator i = oldBlock->capture_begin(),
+           e = oldBlock->capture_end(); i != e; ++i) {
+      VarDecl *oldCapture = i->getVariable();
+
+      // Ignore parameter packs.
+      if (isa<ParmVarDecl>(oldCapture) &&
+          cast<ParmVarDecl>(oldCapture)->isParameterPack())
+        continue;
+
+      VarDecl *newCapture =
+        cast<VarDecl>(getDerived().TransformDecl(E->getCaretLocation(),
+                                                 oldCapture));
+      assert(blockScope->CaptureMap.count(newCapture));
+    }
+    assert(oldBlock->capturesCXXThis() == blockScope->isCXXThisCaptured());
+  }
+#endif
+
+  return SemaRef.ActOnBlockStmtExpr(E->getCaretLocation(), body.get(),
+                                    /*Scope=*/0);
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformAsTypeExpr(AsTypeExpr *E) {
+  llvm_unreachable("Cannot transform asType expressions yet");
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformAtomicExpr(AtomicExpr *E) {
+  QualType RetTy = getDerived().TransformType(E->getType());
+  bool ArgumentChanged = false;
+  ASTOwningVector<Expr*> SubExprs(SemaRef);
+  SubExprs.reserve(E->getNumSubExprs());
+  if (getDerived().TransformExprs(E->getSubExprs(), E->getNumSubExprs(), false,
+                                  SubExprs, &ArgumentChanged))
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() &&
+      !ArgumentChanged)
+    return SemaRef.Owned(E);
+
+  return getDerived().RebuildAtomicExpr(E->getBuiltinLoc(), move_arg(SubExprs),
+                                        RetTy, E->getOp(), E->getRParenLoc());
+}
+  
+//===----------------------------------------------------------------------===//
+// Type reconstruction
+//===----------------------------------------------------------------------===//
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildPointerType(QualType PointeeType,
+                                                    SourceLocation Star) {
+  return SemaRef.BuildPointerType(PointeeType, Star,
+                                  getDerived().getBaseEntity());
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildBlockPointerType(QualType PointeeType,
+                                                         SourceLocation Star) {
+  return SemaRef.BuildBlockPointerType(PointeeType, Star,
+                                       getDerived().getBaseEntity());
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildReferenceType(QualType ReferentType,
+                                             bool WrittenAsLValue,
+                                             SourceLocation Sigil) {
+  return SemaRef.BuildReferenceType(ReferentType, WrittenAsLValue,
+                                    Sigil, getDerived().getBaseEntity());
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildMemberPointerType(QualType PointeeType,
+                                                 QualType ClassType,
+                                                 SourceLocation Sigil) {
+  return SemaRef.BuildMemberPointerType(PointeeType, ClassType,
+                                        Sigil, getDerived().getBaseEntity());
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildArrayType(QualType ElementType,
+                                         ArrayType::ArraySizeModifier SizeMod,
+                                         const llvm::APInt *Size,
+                                         Expr *SizeExpr,
+                                         unsigned IndexTypeQuals,
+                                         SourceRange BracketsRange) {
+  if (SizeExpr || !Size)
+    return SemaRef.BuildArrayType(ElementType, SizeMod, SizeExpr,
+                                  IndexTypeQuals, BracketsRange,
+                                  getDerived().getBaseEntity());
+
+  QualType Types[] = {
+    SemaRef.Context.UnsignedCharTy, SemaRef.Context.UnsignedShortTy,
+    SemaRef.Context.UnsignedIntTy, SemaRef.Context.UnsignedLongTy,
+    SemaRef.Context.UnsignedLongLongTy, SemaRef.Context.UnsignedInt128Ty
+  };
+  const unsigned NumTypes = sizeof(Types) / sizeof(QualType);
+  QualType SizeType;
+  for (unsigned I = 0; I != NumTypes; ++I)
+    if (Size->getBitWidth() == SemaRef.Context.getIntWidth(Types[I])) {
+      SizeType = Types[I];
+      break;
+    }
+
+  // Note that we can return a VariableArrayType here in the case where
+  // the element type was a dependent VariableArrayType.
+  IntegerLiteral *ArraySize
+      = IntegerLiteral::Create(SemaRef.Context, *Size, SizeType,
+                               /*FIXME*/BracketsRange.getBegin());
+  return SemaRef.BuildArrayType(ElementType, SizeMod, ArraySize,
+                                IndexTypeQuals, BracketsRange,
+                                getDerived().getBaseEntity());
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildConstantArrayType(QualType ElementType,
+                                                 ArrayType::ArraySizeModifier SizeMod,
+                                                 const llvm::APInt &Size,
+                                                 unsigned IndexTypeQuals,
+                                                 SourceRange BracketsRange) {
+  return getDerived().RebuildArrayType(ElementType, SizeMod, &Size, 0,
+                                        IndexTypeQuals, BracketsRange);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildIncompleteArrayType(QualType ElementType,
+                                          ArrayType::ArraySizeModifier SizeMod,
+                                                 unsigned IndexTypeQuals,
+                                                   SourceRange BracketsRange) {
+  return getDerived().RebuildArrayType(ElementType, SizeMod, 0, 0,
+                                       IndexTypeQuals, BracketsRange);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildVariableArrayType(QualType ElementType,
+                                          ArrayType::ArraySizeModifier SizeMod,
+                                                 Expr *SizeExpr,
+                                                 unsigned IndexTypeQuals,
+                                                 SourceRange BracketsRange) {
+  return getDerived().RebuildArrayType(ElementType, SizeMod, 0,
+                                       SizeExpr,
+                                       IndexTypeQuals, BracketsRange);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildDependentSizedArrayType(QualType ElementType,
+                                          ArrayType::ArraySizeModifier SizeMod,
+                                                       Expr *SizeExpr,
+                                                       unsigned IndexTypeQuals,
+                                                   SourceRange BracketsRange) {
+  return getDerived().RebuildArrayType(ElementType, SizeMod, 0,
+                                       SizeExpr,
+                                       IndexTypeQuals, BracketsRange);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildVectorType(QualType ElementType,
+                                               unsigned NumElements,
+                                               VectorType::VectorKind VecKind) {
+  // FIXME: semantic checking!
+  return SemaRef.Context.getVectorType(ElementType, NumElements, VecKind);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildExtVectorType(QualType ElementType,
+                                                      unsigned NumElements,
+                                                 SourceLocation AttributeLoc) {
+  llvm::APInt numElements(SemaRef.Context.getIntWidth(SemaRef.Context.IntTy),
+                          NumElements, true);
+  IntegerLiteral *VectorSize
+    = IntegerLiteral::Create(SemaRef.Context, numElements, SemaRef.Context.IntTy,
+                             AttributeLoc);
+  return SemaRef.BuildExtVectorType(ElementType, VectorSize, AttributeLoc);
+}
+
+template<typename Derived>
+QualType
+TreeTransform<Derived>::RebuildDependentSizedExtVectorType(QualType ElementType,
+                                                           Expr *SizeExpr,
+                                                  SourceLocation AttributeLoc) {
+  return SemaRef.BuildExtVectorType(ElementType, SizeExpr, AttributeLoc);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildFunctionProtoType(QualType T,
+                                                          QualType *ParamTypes,
+                                                        unsigned NumParamTypes,
+                                                          bool Variadic,
+                                                         bool HasTrailingReturn,
+                                                          unsigned Quals,
+                                                  RefQualifierKind RefQualifier,
+                                            const FunctionType::ExtInfo &Info) {
+  return SemaRef.BuildFunctionType(T, ParamTypes, NumParamTypes, Variadic,
+                                   HasTrailingReturn, Quals, RefQualifier,
+                                   getDerived().getBaseLocation(),
+                                   getDerived().getBaseEntity(),
+                                   Info);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildFunctionNoProtoType(QualType T) {
+  return SemaRef.Context.getFunctionNoProtoType(T);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildUnresolvedUsingType(Decl *D) {
+  assert(D && "no decl found");
+  if (D->isInvalidDecl()) return QualType();
+
+  // FIXME: Doesn't account for ObjCInterfaceDecl!
+  TypeDecl *Ty;
+  if (isa<UsingDecl>(D)) {
+    UsingDecl *Using = cast<UsingDecl>(D);
+    assert(Using->isTypeName() &&
+           "UnresolvedUsingTypenameDecl transformed to non-typename using");
+
+    // A valid resolved using typename decl points to exactly one type decl.
+    assert(++Using->shadow_begin() == Using->shadow_end());
+    Ty = cast<TypeDecl>((*Using->shadow_begin())->getTargetDecl());
+    
+  } else {
+    assert(isa<UnresolvedUsingTypenameDecl>(D) &&
+           "UnresolvedUsingTypenameDecl transformed to non-using decl");
+    Ty = cast<UnresolvedUsingTypenameDecl>(D);
+  }
+
+  return SemaRef.Context.getTypeDeclType(Ty);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildTypeOfExprType(Expr *E,
+                                                       SourceLocation Loc) {
+  return SemaRef.BuildTypeofExprType(E, Loc);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildTypeOfType(QualType Underlying) {
+  return SemaRef.Context.getTypeOfType(Underlying);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildDecltypeType(Expr *E,
+                                                     SourceLocation Loc) {
+  return SemaRef.BuildDecltypeType(E, Loc);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildUnaryTransformType(QualType BaseType,
+                                            UnaryTransformType::UTTKind UKind,
+                                            SourceLocation Loc) {
+  return SemaRef.BuildUnaryTransformType(BaseType, UKind, Loc);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildTemplateSpecializationType(
+                                                      TemplateName Template,
+                                             SourceLocation TemplateNameLoc,
+                                     TemplateArgumentListInfo &TemplateArgs) {
+  return SemaRef.CheckTemplateIdType(Template, TemplateNameLoc, TemplateArgs);
+}
+
+template<typename Derived>
+QualType TreeTransform<Derived>::RebuildAtomicType(QualType ValueType,
+                                                   SourceLocation KWLoc) {
+  return SemaRef.BuildAtomicType(ValueType, KWLoc);
+}
+
+template<typename Derived>
+TemplateName
+TreeTransform<Derived>::RebuildTemplateName(CXXScopeSpec &SS,
+                                            bool TemplateKW,
+                                            TemplateDecl *Template) {
+  return SemaRef.Context.getQualifiedTemplateName(SS.getScopeRep(), TemplateKW,
+                                                  Template);
+}
+
+template<typename Derived>
+TemplateName
+TreeTransform<Derived>::RebuildTemplateName(CXXScopeSpec &SS,
+                                            const IdentifierInfo &Name,
+                                            SourceLocation NameLoc,
+                                            QualType ObjectType,
+                                            NamedDecl *FirstQualifierInScope) {
+  UnqualifiedId TemplateName;
+  TemplateName.setIdentifier(&Name, NameLoc);
+  Sema::TemplateTy Template;
+  SourceLocation TemplateKWLoc; // FIXME: retrieve it from caller.
+  getSema().ActOnDependentTemplateName(/*Scope=*/0,
+                                       SS, TemplateKWLoc, TemplateName,
+                                       ParsedType::make(ObjectType),
+                                       /*EnteringContext=*/false,
+                                       Template);
+  return Template.get();
+}
+
+template<typename Derived>
+TemplateName
+TreeTransform<Derived>::RebuildTemplateName(CXXScopeSpec &SS,
+                                            OverloadedOperatorKind Operator,
+                                            SourceLocation NameLoc,
+                                            QualType ObjectType) {
+  UnqualifiedId Name;
+  // FIXME: Bogus location information.
+  SourceLocation SymbolLocations[3] = { NameLoc, NameLoc, NameLoc };
+  Name.setOperatorFunctionId(NameLoc, Operator, SymbolLocations);
+  SourceLocation TemplateKWLoc; // FIXME: retrieve it from caller.
+  Sema::TemplateTy Template;
+  getSema().ActOnDependentTemplateName(/*Scope=*/0,
+                                       SS, TemplateKWLoc, Name,
+                                       ParsedType::make(ObjectType),
+                                       /*EnteringContext=*/false,
+                                       Template);
+  return Template.template getAsVal<TemplateName>();
+}
+  
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::RebuildCXXOperatorCallExpr(OverloadedOperatorKind Op,
+                                                   SourceLocation OpLoc,
+                                                   Expr *OrigCallee,
+                                                   Expr *First,
+                                                   Expr *Second) {
+  Expr *Callee = OrigCallee->IgnoreParenCasts();
+  bool isPostIncDec = Second && (Op == OO_PlusPlus || Op == OO_MinusMinus);
+
+  // Determine whether this should be a builtin operation.
+  if (Op == OO_Subscript) {
+    if (!First->getType()->isOverloadableType() &&
+        !Second->getType()->isOverloadableType())
+      return getSema().CreateBuiltinArraySubscriptExpr(First,
+                                                       Callee->getLocStart(),
+                                                       Second, OpLoc);
+  } else if (Op == OO_Arrow) {
+    // -> is never a builtin operation.
+    return SemaRef.BuildOverloadedArrowExpr(0, First, OpLoc);
+  } else if (Second == 0 || isPostIncDec) {
+    if (!First->getType()->isOverloadableType()) {
+      // The argument is not of overloadable type, so try to create a
+      // built-in unary operation.
+      UnaryOperatorKind Opc
+        = UnaryOperator::getOverloadedOpcode(Op, isPostIncDec);
+
+      return getSema().CreateBuiltinUnaryOp(OpLoc, Opc, First);
+    }
+  } else {
+    if (!First->getType()->isOverloadableType() &&
+        !Second->getType()->isOverloadableType()) {
+      // Neither of the arguments is an overloadable type, so try to
+      // create a built-in binary operation.
+      BinaryOperatorKind Opc = BinaryOperator::getOverloadedOpcode(Op);
+      ExprResult Result
+        = SemaRef.CreateBuiltinBinOp(OpLoc, Opc, First, Second);
+      if (Result.isInvalid())
+        return ExprError();
+
+      return move(Result);
+    }
+  }
+
+  // Compute the transformed set of functions (and function templates) to be
+  // used during overload resolution.
+  UnresolvedSet<16> Functions;
+
+  if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(Callee)) {
+    assert(ULE->requiresADL());
+
+    // FIXME: Do we have to check
+    // IsAcceptableNonMemberOperatorCandidate for each of these?
+    Functions.append(ULE->decls_begin(), ULE->decls_end());
+  } else {
+    Functions.addDecl(cast<DeclRefExpr>(Callee)->getDecl());
+  }
+
+  // Add any functions found via argument-dependent lookup.
+  Expr *Args[2] = { First, Second };
+  unsigned NumArgs = 1 + (Second != 0);
+
+  // Create the overloaded operator invocation for unary operators.
+  if (NumArgs == 1 || isPostIncDec) {
+    UnaryOperatorKind Opc
+      = UnaryOperator::getOverloadedOpcode(Op, isPostIncDec);
+    return SemaRef.CreateOverloadedUnaryOp(OpLoc, Opc, Functions, First);
+  }
+
+  if (Op == OO_Subscript) {
+    SourceLocation LBrace;
+    SourceLocation RBrace;
+
+    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Callee)) {
+        DeclarationNameLoc &NameLoc = DRE->getNameInfo().getInfo();
+        LBrace = SourceLocation::getFromRawEncoding(
+                    NameLoc.CXXOperatorName.BeginOpNameLoc);
+        RBrace = SourceLocation::getFromRawEncoding(
+                    NameLoc.CXXOperatorName.EndOpNameLoc);
+    } else {
+        LBrace = Callee->getLocStart();
+        RBrace = OpLoc;
+    }
+
+    return SemaRef.CreateOverloadedArraySubscriptExpr(LBrace, RBrace,
+                                                      First, Second);
+  }
+
+  // Create the overloaded operator invocation for binary operators.
+  BinaryOperatorKind Opc = BinaryOperator::getOverloadedOpcode(Op);
+  ExprResult Result
+    = SemaRef.CreateOverloadedBinOp(OpLoc, Opc, Functions, Args[0], Args[1]);
+  if (Result.isInvalid())
+    return ExprError();
+
+  return move(Result);
+}
+
+template<typename Derived>
+ExprResult 
+TreeTransform<Derived>::RebuildCXXPseudoDestructorExpr(Expr *Base,
+                                                     SourceLocation OperatorLoc,
+                                                       bool isArrow,
+                                                       CXXScopeSpec &SS,
+                                                     TypeSourceInfo *ScopeType,
+                                                       SourceLocation CCLoc,
+                                                       SourceLocation TildeLoc,
+                                        PseudoDestructorTypeStorage Destroyed) {
+  QualType BaseType = Base->getType();
+  if (Base->isTypeDependent() || Destroyed.getIdentifier() ||
+      (!isArrow && !BaseType->getAs<RecordType>()) ||
+      (isArrow && BaseType->getAs<PointerType>() && 
+       !BaseType->getAs<PointerType>()->getPointeeType()
+                                              ->template getAs<RecordType>())){
+    // This pseudo-destructor expression is still a pseudo-destructor.
+    return SemaRef.BuildPseudoDestructorExpr(Base, OperatorLoc,
+                                             isArrow? tok::arrow : tok::period,
+                                             SS, ScopeType, CCLoc, TildeLoc,
+                                             Destroyed,
+                                             /*FIXME?*/true);
+  }
+
+  TypeSourceInfo *DestroyedType = Destroyed.getTypeSourceInfo();
+  DeclarationName Name(SemaRef.Context.DeclarationNames.getCXXDestructorName(
+                 SemaRef.Context.getCanonicalType(DestroyedType->getType())));
+  DeclarationNameInfo NameInfo(Name, Destroyed.getLocation());
+  NameInfo.setNamedTypeInfo(DestroyedType);
+
+  // FIXME: the ScopeType should be tacked onto SS.
+
+  SourceLocation TemplateKWLoc; // FIXME: retrieve it from caller.
+  return getSema().BuildMemberReferenceExpr(Base, BaseType,
+                                            OperatorLoc, isArrow,
+                                            SS, TemplateKWLoc,
+                                            /*FIXME: FirstQualifier*/ 0,
+                                            NameInfo,
+                                            /*TemplateArgs*/ 0);
+}
+
+} // end namespace clang
+
+#endif // LLVM_CLANG_SEMA_TREETRANSFORM_H