Import Clang, at r72732.vendor/clang/clang-r72732

1 files changed, 2823 insertions, 0 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
new file mode 100644
index 000000000000..f13179f0438f
--- /dev/null
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -0,0 +1,2823 @@
+//===------ SemaDeclCXX.cpp - Semantic Analysis for C++ Declarations ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements semantic analysis for C++ declarations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Sema.h"
+#include "SemaInherit.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclVisitor.h"
+#include "clang/AST/TypeOrdering.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Parse/DeclSpec.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Compiler.h"
+#include <algorithm> // for std::equal
+#include <map>
+
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// CheckDefaultArgumentVisitor
+//===----------------------------------------------------------------------===//
+
+namespace {
+  /// CheckDefaultArgumentVisitor - C++ [dcl.fct.default] Traverses
+  /// the default argument of a parameter to determine whether it
+  /// contains any ill-formed subexpressions. For example, this will
+  /// diagnose the use of local variables or parameters within the
+  /// default argument expression.
+  class VISIBILITY_HIDDEN CheckDefaultArgumentVisitor 
+    : public StmtVisitor<CheckDefaultArgumentVisitor, bool> {
+    Expr *DefaultArg;
+    Sema *S;
+
+  public:
+    CheckDefaultArgumentVisitor(Expr *defarg, Sema *s) 
+      : DefaultArg(defarg), S(s) {}
+
+    bool VisitExpr(Expr *Node);
+    bool VisitDeclRefExpr(DeclRefExpr *DRE);
+    bool VisitCXXThisExpr(CXXThisExpr *ThisE);
+  };
+
+  /// VisitExpr - Visit all of the children of this expression.
+  bool CheckDefaultArgumentVisitor::VisitExpr(Expr *Node) {
+    bool IsInvalid = false;
+    for (Stmt::child_iterator I = Node->child_begin(), 
+         E = Node->child_end(); I != E; ++I)
+      IsInvalid |= Visit(*I);
+    return IsInvalid;
+  }
+
+  /// VisitDeclRefExpr - Visit a reference to a declaration, to
+  /// determine whether this declaration can be used in the default
+  /// argument expression.
+  bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(DeclRefExpr *DRE) {
+    NamedDecl *Decl = DRE->getDecl();
+    if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(Decl)) {
+      // C++ [dcl.fct.default]p9
+      //   Default arguments are evaluated each time the function is
+      //   called. The order of evaluation of function arguments is
+      //   unspecified. Consequently, parameters of a function shall not
+      //   be used in default argument expressions, even if they are not
+      //   evaluated. Parameters of a function declared before a default
+      //   argument expression are in scope and can hide namespace and
+      //   class member names.
+      return S->Diag(DRE->getSourceRange().getBegin(), 
+                     diag::err_param_default_argument_references_param)
+         << Param->getDeclName() << DefaultArg->getSourceRange();
+    } else if (VarDecl *VDecl = dyn_cast<VarDecl>(Decl)) {
+      // C++ [dcl.fct.default]p7
+      //   Local variables shall not be used in default argument
+      //   expressions.
+      if (VDecl->isBlockVarDecl())
+        return S->Diag(DRE->getSourceRange().getBegin(), 
+                       diag::err_param_default_argument_references_local)
+          << VDecl->getDeclName() << DefaultArg->getSourceRange();
+    }
+
+    return false;
+  }
+
+  /// VisitCXXThisExpr - Visit a C++ "this" expression.
+  bool CheckDefaultArgumentVisitor::VisitCXXThisExpr(CXXThisExpr *ThisE) {
+    // C++ [dcl.fct.default]p8:
+    //   The keyword this shall not be used in a default argument of a
+    //   member function.
+    return S->Diag(ThisE->getSourceRange().getBegin(),
+                   diag::err_param_default_argument_references_this)
+               << ThisE->getSourceRange();
+  }
+}
+
+/// ActOnParamDefaultArgument - Check whether the default argument
+/// provided for a function parameter is well-formed. If so, attach it
+/// to the parameter declaration.
+void
+Sema::ActOnParamDefaultArgument(DeclPtrTy param, SourceLocation EqualLoc, 
+                                ExprArg defarg) {
+  ParmVarDecl *Param = cast<ParmVarDecl>(param.getAs<Decl>());
+  ExprOwningPtr<Expr> DefaultArg(this, defarg.takeAs<Expr>());
+  QualType ParamType = Param->getType();
+
+  // Default arguments are only permitted in C++
+  if (!getLangOptions().CPlusPlus) {
+    Diag(EqualLoc, diag::err_param_default_argument)
+      << DefaultArg->getSourceRange();
+    Param->setInvalidDecl();
+    return;
+  }
+
+  // C++ [dcl.fct.default]p5
+  //   A default argument expression is implicitly converted (clause
+  //   4) to the parameter type. The default argument expression has
+  //   the same semantic constraints as the initializer expression in
+  //   a declaration of a variable of the parameter type, using the
+  //   copy-initialization semantics (8.5).
+  Expr *DefaultArgPtr = DefaultArg.get();
+  bool DefaultInitFailed = CheckInitializerTypes(DefaultArgPtr, ParamType,
+                                                 EqualLoc,
+                                                 Param->getDeclName(),
+                                                 /*DirectInit=*/false);
+  if (DefaultArgPtr != DefaultArg.get()) {
+    DefaultArg.take();
+    DefaultArg.reset(DefaultArgPtr);
+  }
+  if (DefaultInitFailed) {
+    return;
+  }
+
+  // Check that the default argument is well-formed
+  CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg.get(), this);
+  if (DefaultArgChecker.Visit(DefaultArg.get())) {
+    Param->setInvalidDecl();
+    return;
+  }
+
+  // Okay: add the default argument to the parameter
+  Param->setDefaultArg(DefaultArg.take());
+}
+
+/// ActOnParamUnparsedDefaultArgument - We've seen a default
+/// argument for a function parameter, but we can't parse it yet
+/// because we're inside a class definition. Note that this default
+/// argument will be parsed later.
+void Sema::ActOnParamUnparsedDefaultArgument(DeclPtrTy param, 
+                                             SourceLocation EqualLoc) {
+  ParmVarDecl *Param = cast<ParmVarDecl>(param.getAs<Decl>());
+  if (Param)
+    Param->setUnparsedDefaultArg();
+}
+
+/// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
+/// the default argument for the parameter param failed.
+void Sema::ActOnParamDefaultArgumentError(DeclPtrTy param) {
+  cast<ParmVarDecl>(param.getAs<Decl>())->setInvalidDecl();
+}
+
+/// CheckExtraCXXDefaultArguments - Check for any extra default
+/// arguments in the declarator, which is not a function declaration
+/// or definition and therefore is not permitted to have default
+/// arguments. This routine should be invoked for every declarator
+/// that is not a function declaration or definition.
+void Sema::CheckExtraCXXDefaultArguments(Declarator &D) {
+  // C++ [dcl.fct.default]p3
+  //   A default argument expression shall be specified only in the
+  //   parameter-declaration-clause of a function declaration or in a
+  //   template-parameter (14.1). It shall not be specified for a
+  //   parameter pack. If it is specified in a
+  //   parameter-declaration-clause, it shall not occur within a
+  //   declarator or abstract-declarator of a parameter-declaration.
+  for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
+    DeclaratorChunk &chunk = D.getTypeObject(i);
+    if (chunk.Kind == DeclaratorChunk::Function) {
+      for (unsigned argIdx = 0, e = chunk.Fun.NumArgs; argIdx != e; ++argIdx) {
+        ParmVarDecl *Param =
+          cast<ParmVarDecl>(chunk.Fun.ArgInfo[argIdx].Param.getAs<Decl>());
+        if (Param->hasUnparsedDefaultArg()) {
+          CachedTokens *Toks = chunk.Fun.ArgInfo[argIdx].DefaultArgTokens;
+          Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
+            << SourceRange((*Toks)[1].getLocation(), Toks->back().getLocation());
+          delete Toks;
+          chunk.Fun.ArgInfo[argIdx].DefaultArgTokens = 0;
+        } else if (Param->getDefaultArg()) {
+          Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
+            << Param->getDefaultArg()->getSourceRange();
+          Param->setDefaultArg(0);
+        }
+      }
+    }
+  }
+}
+
+// MergeCXXFunctionDecl - Merge two declarations of the same C++
+// function, once we already know that they have the same
+// type. Subroutine of MergeFunctionDecl. Returns true if there was an
+// error, false otherwise.
+bool Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) {
+  bool Invalid = false;
+
+  // C++ [dcl.fct.default]p4:
+  //
+  //   For non-template functions, default arguments can be added in
+  //   later declarations of a function in the same
+  //   scope. Declarations in different scopes have completely
+  //   distinct sets of default arguments. That is, declarations in
+  //   inner scopes do not acquire default arguments from
+  //   declarations in outer scopes, and vice versa. In a given
+  //   function declaration, all parameters subsequent to a
+  //   parameter with a default argument shall have default
+  //   arguments supplied in this or previous declarations. A
+  //   default argument shall not be redefined by a later
+  //   declaration (not even to the same value).
+  for (unsigned p = 0, NumParams = Old->getNumParams(); p < NumParams; ++p) {
+    ParmVarDecl *OldParam = Old->getParamDecl(p);
+    ParmVarDecl *NewParam = New->getParamDecl(p);
+
+    if(OldParam->getDefaultArg() && NewParam->getDefaultArg()) {
+      Diag(NewParam->getLocation(), 
+           diag::err_param_default_argument_redefinition)
+        << NewParam->getDefaultArg()->getSourceRange();
+      Diag(OldParam->getLocation(), diag::note_previous_definition);
+      Invalid = true;
+    } else if (OldParam->getDefaultArg()) {
+      // Merge the old default argument into the new parameter
+      NewParam->setDefaultArg(OldParam->getDefaultArg());
+    }
+  }
+
+  return Invalid;
+}
+
+/// CheckCXXDefaultArguments - Verify that the default arguments for a
+/// function declaration are well-formed according to C++
+/// [dcl.fct.default].
+void Sema::CheckCXXDefaultArguments(FunctionDecl *FD) {
+  unsigned NumParams = FD->getNumParams();
+  unsigned p;
+
+  // Find first parameter with a default argument
+  for (p = 0; p < NumParams; ++p) {
+    ParmVarDecl *Param = FD->getParamDecl(p);
+    if (Param->getDefaultArg())
+      break;
+  }
+
+  // C++ [dcl.fct.default]p4:
+  //   In a given function declaration, all parameters
+  //   subsequent to a parameter with a default argument shall
+  //   have default arguments supplied in this or previous
+  //   declarations. A default argument shall not be redefined
+  //   by a later declaration (not even to the same value).
+  unsigned LastMissingDefaultArg = 0;
+  for(; p < NumParams; ++p) {
+    ParmVarDecl *Param = FD->getParamDecl(p);
+    if (!Param->getDefaultArg()) {
+      if (Param->isInvalidDecl())
+        /* We already complained about this parameter. */;
+      else if (Param->getIdentifier())
+        Diag(Param->getLocation(), 
+             diag::err_param_default_argument_missing_name)
+          << Param->getIdentifier();
+      else
+        Diag(Param->getLocation(), 
+             diag::err_param_default_argument_missing);
+    
+      LastMissingDefaultArg = p;
+    }
+  }
+
+  if (LastMissingDefaultArg > 0) {
+    // Some default arguments were missing. Clear out all of the
+    // default arguments up to (and including) the last missing
+    // default argument, so that we leave the function parameters
+    // in a semantically valid state.
+    for (p = 0; p <= LastMissingDefaultArg; ++p) {
+      ParmVarDecl *Param = FD->getParamDecl(p);
+      if (Param->getDefaultArg()) {
+        if (!Param->hasUnparsedDefaultArg())
+          Param->getDefaultArg()->Destroy(Context);
+        Param->setDefaultArg(0);
+      }
+    }
+  }
+}
+
+/// isCurrentClassName - Determine whether the identifier II is the
+/// name of the class type currently being defined. In the case of
+/// nested classes, this will only return true if II is the name of
+/// the innermost class.
+bool Sema::isCurrentClassName(const IdentifierInfo &II, Scope *,
+                              const CXXScopeSpec *SS) {
+  CXXRecordDecl *CurDecl;
+  if (SS && SS->isSet() && !SS->isInvalid()) {
+    DeclContext *DC = computeDeclContext(*SS);
+    CurDecl = dyn_cast_or_null<CXXRecordDecl>(DC);
+  } else
+    CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext);
+
+  if (CurDecl)
+    return &II == CurDecl->getIdentifier();
+  else
+    return false;
+}
+
+/// \brief Check the validity of a C++ base class specifier. 
+///
+/// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
+/// and returns NULL otherwise.
+CXXBaseSpecifier *
+Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
+                         SourceRange SpecifierRange,
+                         bool Virtual, AccessSpecifier Access,
+                         QualType BaseType, 
+                         SourceLocation BaseLoc) {
+  // C++ [class.union]p1:
+  //   A union shall not have base classes.
+  if (Class->isUnion()) {
+    Diag(Class->getLocation(), diag::err_base_clause_on_union)
+      << SpecifierRange;
+    return 0;
+  }
+
+  if (BaseType->isDependentType())
+    return new CXXBaseSpecifier(SpecifierRange, Virtual, 
+                                Class->getTagKind() == RecordDecl::TK_class,
+                                Access, BaseType);
+
+  // Base specifiers must be record types.
+  if (!BaseType->isRecordType()) {
+    Diag(BaseLoc, diag::err_base_must_be_class) << SpecifierRange;
+    return 0;
+  }
+
+  // C++ [class.union]p1:
+  //   A union shall not be used as a base class.
+  if (BaseType->isUnionType()) {
+    Diag(BaseLoc, diag::err_union_as_base_class) << SpecifierRange;
+    return 0;
+  }
+
+  // C++ [class.derived]p2:
+  //   The class-name in a base-specifier shall not be an incompletely
+  //   defined class.
+  if (RequireCompleteType(BaseLoc, BaseType, diag::err_incomplete_base_class,
+                          SpecifierRange))
+    return 0;
+
+  // If the base class is polymorphic, the new one is, too.
+  RecordDecl *BaseDecl = BaseType->getAsRecordType()->getDecl();
+  assert(BaseDecl && "Record type has no declaration");
+  BaseDecl = BaseDecl->getDefinition(Context);
+  assert(BaseDecl && "Base type is not incomplete, but has no definition");
+  if (cast<CXXRecordDecl>(BaseDecl)->isPolymorphic())
+    Class->setPolymorphic(true);
+
+  // C++ [dcl.init.aggr]p1:
+  //   An aggregate is [...] a class with [...] no base classes [...].
+  Class->setAggregate(false);
+  Class->setPOD(false);
+
+  if (Virtual) {
+    // C++ [class.ctor]p5:
+    //   A constructor is trivial if its class has no virtual base classes.
+    Class->setHasTrivialConstructor(false);
+  } else {
+    // C++ [class.ctor]p5:
+    //   A constructor is trivial if all the direct base classes of its 
+    //   class have trivial constructors.
+    Class->setHasTrivialConstructor(cast<CXXRecordDecl>(BaseDecl)->
+                                    hasTrivialConstructor());
+  }
+
+  // C++ [class.ctor]p3:
+  //   A destructor is trivial if all the direct base classes of its class
+  //   have trivial destructors.
+  Class->setHasTrivialDestructor(cast<CXXRecordDecl>(BaseDecl)->
+                                 hasTrivialDestructor());
+  
+  // Create the base specifier.
+  // FIXME: Allocate via ASTContext?
+  return new CXXBaseSpecifier(SpecifierRange, Virtual, 
+                              Class->getTagKind() == RecordDecl::TK_class, 
+                              Access, BaseType);
+}
+
+/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
+/// one entry in the base class list of a class specifier, for
+/// example: 
+///    class foo : public bar, virtual private baz { 
+/// 'public bar' and 'virtual private baz' are each base-specifiers.
+Sema::BaseResult 
+Sema::ActOnBaseSpecifier(DeclPtrTy classdecl, SourceRange SpecifierRange,
+                         bool Virtual, AccessSpecifier Access,
+                         TypeTy *basetype, SourceLocation BaseLoc) {
+  AdjustDeclIfTemplate(classdecl);
+  CXXRecordDecl *Class = cast<CXXRecordDecl>(classdecl.getAs<Decl>());
+  QualType BaseType = QualType::getFromOpaquePtr(basetype);
+  if (CXXBaseSpecifier *BaseSpec = CheckBaseSpecifier(Class, SpecifierRange,
+                                                      Virtual, Access,
+                                                      BaseType, BaseLoc))
+    return BaseSpec;
+  
+  return true;
+}
+
+/// \brief Performs the actual work of attaching the given base class
+/// specifiers to a C++ class.
+bool Sema::AttachBaseSpecifiers(CXXRecordDecl *Class, CXXBaseSpecifier **Bases,
+                                unsigned NumBases) {
+ if (NumBases == 0)
+    return false;
+
+  // Used to keep track of which base types we have already seen, so
+  // that we can properly diagnose redundant direct base types. Note
+  // that the key is always the unqualified canonical type of the base
+  // class.
+  std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes;
+
+  // Copy non-redundant base specifiers into permanent storage.
+  unsigned NumGoodBases = 0;
+  bool Invalid = false;
+  for (unsigned idx = 0; idx < NumBases; ++idx) {
+    QualType NewBaseType 
+      = Context.getCanonicalType(Bases[idx]->getType());
+    NewBaseType = NewBaseType.getUnqualifiedType();
+
+    if (KnownBaseTypes[NewBaseType]) {
+      // C++ [class.mi]p3:
+      //   A class shall not be specified as a direct base class of a
+      //   derived class more than once.
+      Diag(Bases[idx]->getSourceRange().getBegin(),
+           diag::err_duplicate_base_class)
+        << KnownBaseTypes[NewBaseType]->getType()
+        << Bases[idx]->getSourceRange();
+
+      // Delete the duplicate base class specifier; we're going to
+      // overwrite its pointer later.
+      delete Bases[idx];
+
+      Invalid = true;
+    } else {
+      // Okay, add this new base class.
+      KnownBaseTypes[NewBaseType] = Bases[idx];
+      Bases[NumGoodBases++] = Bases[idx];
+    }
+  }
+
+  // Attach the remaining base class specifiers to the derived class.
+  Class->setBases(Bases, NumGoodBases);
+
+  // Delete the remaining (good) base class specifiers, since their
+  // data has been copied into the CXXRecordDecl.
+  for (unsigned idx = 0; idx < NumGoodBases; ++idx)
+    delete Bases[idx];
+
+  return Invalid;
+}
+
+/// ActOnBaseSpecifiers - Attach the given base specifiers to the
+/// class, after checking whether there are any duplicate base
+/// classes.
+void Sema::ActOnBaseSpecifiers(DeclPtrTy ClassDecl, BaseTy **Bases, 
+                               unsigned NumBases) {
+  if (!ClassDecl || !Bases || !NumBases)
+    return;
+
+  AdjustDeclIfTemplate(ClassDecl);
+  AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl.getAs<Decl>()),
+                       (CXXBaseSpecifier**)(Bases), NumBases);
+}
+
+//===----------------------------------------------------------------------===//
+// C++ class member Handling
+//===----------------------------------------------------------------------===//
+
+/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
+/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
+/// bitfield width if there is one and 'InitExpr' specifies the initializer if
+/// any.
+Sema::DeclPtrTy
+Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
+                               ExprTy *BW, ExprTy *InitExpr, bool Deleted) {
+  const DeclSpec &DS = D.getDeclSpec();
+  DeclarationName Name = GetNameForDeclarator(D);
+  Expr *BitWidth = static_cast<Expr*>(BW);
+  Expr *Init = static_cast<Expr*>(InitExpr);
+  SourceLocation Loc = D.getIdentifierLoc();
+
+  bool isFunc = D.isFunctionDeclarator();
+
+  // C++ 9.2p6: A member shall not be declared to have automatic storage
+  // duration (auto, register) or with the extern storage-class-specifier.
+  // C++ 7.1.1p8: The mutable specifier can be applied only to names of class
+  // data members and cannot be applied to names declared const or static,
+  // and cannot be applied to reference members.
+  switch (DS.getStorageClassSpec()) {
+    case DeclSpec::SCS_unspecified:
+    case DeclSpec::SCS_typedef:
+    case DeclSpec::SCS_static:
+      // FALL THROUGH.
+      break;
+    case DeclSpec::SCS_mutable:
+      if (isFunc) {
+        if (DS.getStorageClassSpecLoc().isValid())
+          Diag(DS.getStorageClassSpecLoc(), diag::err_mutable_function);
+        else
+          Diag(DS.getThreadSpecLoc(), diag::err_mutable_function);
+        
+        // FIXME: It would be nicer if the keyword was ignored only for this
+        // declarator. Otherwise we could get follow-up errors.
+        D.getMutableDeclSpec().ClearStorageClassSpecs();
+      } else {
+        QualType T = GetTypeForDeclarator(D, S);
+        diag::kind err = static_cast<diag::kind>(0);
+        if (T->isReferenceType())
+          err = diag::err_mutable_reference;
+        else if (T.isConstQualified())
+          err = diag::err_mutable_const;
+        if (err != 0) {
+          if (DS.getStorageClassSpecLoc().isValid())
+            Diag(DS.getStorageClassSpecLoc(), err);
+          else
+            Diag(DS.getThreadSpecLoc(), err);
+          // FIXME: It would be nicer if the keyword was ignored only for this
+          // declarator. Otherwise we could get follow-up errors.
+          D.getMutableDeclSpec().ClearStorageClassSpecs();
+        }
+      }
+      break;
+    default:
+      if (DS.getStorageClassSpecLoc().isValid())
+        Diag(DS.getStorageClassSpecLoc(),
+             diag::err_storageclass_invalid_for_member);
+      else
+        Diag(DS.getThreadSpecLoc(), diag::err_storageclass_invalid_for_member);
+      D.getMutableDeclSpec().ClearStorageClassSpecs();
+  }
+
+  if (!isFunc &&
+      D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_typename &&
+      D.getNumTypeObjects() == 0) {
+    // Check also for this case:
+    //
+    // typedef int f();
+    // f a;
+    //
+    QualType TDType = QualType::getFromOpaquePtr(DS.getTypeRep());
+    isFunc = TDType->isFunctionType();
+  }
+
+  bool isInstField = ((DS.getStorageClassSpec() == DeclSpec::SCS_unspecified ||
+                       DS.getStorageClassSpec() == DeclSpec::SCS_mutable) &&
+                      !isFunc);
+
+  Decl *Member;
+  if (isInstField) {
+    Member = HandleField(S, cast<CXXRecordDecl>(CurContext), Loc, D, BitWidth,
+                         AS);
+    assert(Member && "HandleField never returns null");
+  } else {
+    Member = ActOnDeclarator(S, D).getAs<Decl>();
+    if (!Member) {
+      if (BitWidth) DeleteExpr(BitWidth);
+      return DeclPtrTy();
+    }
+
+    // Non-instance-fields can't have a bitfield.
+    if (BitWidth) {
+      if (Member->isInvalidDecl()) {
+        // don't emit another diagnostic.
+      } else if (isa<VarDecl>(Member)) {
+        // C++ 9.6p3: A bit-field shall not be a static member.
+        // "static member 'A' cannot be a bit-field"
+        Diag(Loc, diag::err_static_not_bitfield)
+          << Name << BitWidth->getSourceRange();
+      } else if (isa<TypedefDecl>(Member)) {
+        // "typedef member 'x' cannot be a bit-field"
+        Diag(Loc, diag::err_typedef_not_bitfield)
+          << Name << BitWidth->getSourceRange();
+      } else {
+        // A function typedef ("typedef int f(); f a;").
+        // C++ 9.6p3: A bit-field shall have integral or enumeration type.
+        Diag(Loc, diag::err_not_integral_type_bitfield)
+          << Name << cast<ValueDecl>(Member)->getType() 
+          << BitWidth->getSourceRange();
+      }
+      
+      DeleteExpr(BitWidth);
+      BitWidth = 0;
+      Member->setInvalidDecl();
+    }
+
+    Member->setAccess(AS);
+  }
+
+  assert((Name || isInstField) && "No identifier for non-field ?");
+
+  if (Init)
+    AddInitializerToDecl(DeclPtrTy::make(Member), ExprArg(*this, Init), false);
+  if (Deleted) // FIXME: Source location is not very good.
+    SetDeclDeleted(DeclPtrTy::make(Member), D.getSourceRange().getBegin());
+
+  if (isInstField) {
+    FieldCollector->Add(cast<FieldDecl>(Member));
+    return DeclPtrTy();
+  }
+  return DeclPtrTy::make(Member);
+}
+
+/// ActOnMemInitializer - Handle a C++ member initializer.
+Sema::MemInitResult 
+Sema::ActOnMemInitializer(DeclPtrTy ConstructorD,
+                          Scope *S,
+                          IdentifierInfo *MemberOrBase,
+                          SourceLocation IdLoc,
+                          SourceLocation LParenLoc,
+                          ExprTy **Args, unsigned NumArgs,
+                          SourceLocation *CommaLocs,
+                          SourceLocation RParenLoc) {
+  CXXConstructorDecl *Constructor 
+    = dyn_cast<CXXConstructorDecl>(ConstructorD.getAs<Decl>());
+  if (!Constructor) {
+    // The user wrote a constructor initializer on a function that is
+    // not a C++ constructor. Ignore the error for now, because we may
+    // have more member initializers coming; we'll diagnose it just
+    // once in ActOnMemInitializers.
+    return true;
+  }
+
+  CXXRecordDecl *ClassDecl = Constructor->getParent();
+
+  // C++ [class.base.init]p2:
+  //   Names in a mem-initializer-id are looked up in the scope of the
+  //   constructor’s class and, if not found in that scope, are looked
+  //   up in the scope containing the constructor’s
+  //   definition. [Note: if the constructor’s class contains a member
+  //   with the same name as a direct or virtual base class of the
+  //   class, a mem-initializer-id naming the member or base class and
+  //   composed of a single identifier refers to the class member. A
+  //   mem-initializer-id for the hidden base class may be specified
+  //   using a qualified name. ]
+  // Look for a member, first.
+  FieldDecl *Member = 0;
+  DeclContext::lookup_result Result 
+    = ClassDecl->lookup(Context, MemberOrBase);
+  if (Result.first != Result.second)
+    Member = dyn_cast<FieldDecl>(*Result.first);
+
+  // FIXME: Handle members of an anonymous union.
+
+  if (Member) {
+    // FIXME: Perform direct initialization of the member.
+    return new CXXBaseOrMemberInitializer(Member, (Expr **)Args, NumArgs);
+  }
+
+  // It didn't name a member, so see if it names a class.
+  TypeTy *BaseTy = getTypeName(*MemberOrBase, IdLoc, S, 0/*SS*/);
+  if (!BaseTy)
+    return Diag(IdLoc, diag::err_mem_init_not_member_or_class)
+      << MemberOrBase << SourceRange(IdLoc, RParenLoc);
+  
+  QualType BaseType = QualType::getFromOpaquePtr(BaseTy);
+  if (!BaseType->isRecordType())
+    return Diag(IdLoc, diag::err_base_init_does_not_name_class)
+      << BaseType << SourceRange(IdLoc, RParenLoc);
+
+  // C++ [class.base.init]p2:
+  //   [...] Unless the mem-initializer-id names a nonstatic data
+  //   member of the constructor’s class or a direct or virtual base
+  //   of that class, the mem-initializer is ill-formed. A
+  //   mem-initializer-list can initialize a base class using any
+  //   name that denotes that base class type.
+  
+  // First, check for a direct base class.
+  const CXXBaseSpecifier *DirectBaseSpec = 0;
+  for (CXXRecordDecl::base_class_const_iterator Base = ClassDecl->bases_begin();
+       Base != ClassDecl->bases_end(); ++Base) {
+    if (Context.getCanonicalType(BaseType).getUnqualifiedType() == 
+        Context.getCanonicalType(Base->getType()).getUnqualifiedType()) {
+      // We found a direct base of this type. That's what we're
+      // initializing.
+      DirectBaseSpec = &*Base;
+      break;
+    }
+  }
+  
+  // Check for a virtual base class.
+  // FIXME: We might be able to short-circuit this if we know in advance that
+  // there are no virtual bases.
+  const CXXBaseSpecifier *VirtualBaseSpec = 0;
+  if (!DirectBaseSpec || !DirectBaseSpec->isVirtual()) {
+    // We haven't found a base yet; search the class hierarchy for a
+    // virtual base class.
+    BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
+                    /*DetectVirtual=*/false);
+    if (IsDerivedFrom(Context.getTypeDeclType(ClassDecl), BaseType, Paths)) {
+      for (BasePaths::paths_iterator Path = Paths.begin(); 
+           Path != Paths.end(); ++Path) {
+        if (Path->back().Base->isVirtual()) {
+          VirtualBaseSpec = Path->back().Base;
+          break;
+        }
+      }
+    }
+  }
+
+  // C++ [base.class.init]p2:
+  //   If a mem-initializer-id is ambiguous because it designates both
+  //   a direct non-virtual base class and an inherited virtual base
+  //   class, the mem-initializer is ill-formed.
+  if (DirectBaseSpec && VirtualBaseSpec)
+    return Diag(IdLoc, diag::err_base_init_direct_and_virtual)
+      << MemberOrBase << SourceRange(IdLoc, RParenLoc);
+
+  return new CXXBaseOrMemberInitializer(BaseType, (Expr **)Args, NumArgs);
+}
+
+void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl, 
+                                SourceLocation ColonLoc,
+                                MemInitTy **MemInits, unsigned NumMemInits) {
+  CXXConstructorDecl *Constructor = 
+  dyn_cast<CXXConstructorDecl>(ConstructorDecl.getAs<Decl>());
+  
+  if (!Constructor) {
+    Diag(ColonLoc, diag::err_only_constructors_take_base_inits);
+    return;
+  }
+}
+
+namespace {
+  /// PureVirtualMethodCollector - traverses a class and its superclasses
+  /// and determines if it has any pure virtual methods.
+  class VISIBILITY_HIDDEN PureVirtualMethodCollector {
+    ASTContext &Context;
+
+  public:
+    typedef llvm::SmallVector<const CXXMethodDecl*, 8> MethodList;
+
+  private:
+    MethodList Methods;
+    
+    void Collect(const CXXRecordDecl* RD, MethodList& Methods);
+    
+  public:
+    PureVirtualMethodCollector(ASTContext &Ctx, const CXXRecordDecl* RD) 
+      : Context(Ctx) {
+        
+      MethodList List;
+      Collect(RD, List);
+        
+      // Copy the temporary list to methods, and make sure to ignore any
+      // null entries.
+      for (size_t i = 0, e = List.size(); i != e; ++i) {
+        if (List[i])
+          Methods.push_back(List[i]);
+      }          
+    }
+    
+    bool empty() const { return Methods.empty(); }
+    
+    MethodList::const_iterator methods_begin() { return Methods.begin(); }
+    MethodList::const_iterator methods_end() { return Methods.end(); }
+  };
+  
+  void PureVirtualMethodCollector::Collect(const CXXRecordDecl* RD, 
+                                           MethodList& Methods) {
+    // First, collect the pure virtual methods for the base classes.
+    for (CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin(),
+         BaseEnd = RD->bases_end(); Base != BaseEnd; ++Base) {
+      if (const RecordType *RT = Base->getType()->getAsRecordType()) {
+        const CXXRecordDecl *BaseDecl = cast<CXXRecordDecl>(RT->getDecl());
+        if (BaseDecl && BaseDecl->isAbstract())
+          Collect(BaseDecl, Methods);
+      }
+    }
+    
+    // Next, zero out any pure virtual methods that this class overrides.
+    typedef llvm::SmallPtrSet<const CXXMethodDecl*, 4> MethodSetTy;
+  
+    MethodSetTy OverriddenMethods;
+    size_t MethodsSize = Methods.size();
+
+    for (RecordDecl::decl_iterator i = RD->decls_begin(Context), 
+         e = RD->decls_end(Context); 
+         i != e; ++i) {
+      // Traverse the record, looking for methods.
+      if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(*i)) {
+        // If the method is pre virtual, add it to the methods vector.
+        if (MD->isPure()) {
+          Methods.push_back(MD);
+          continue;
+        }
+        
+        // Otherwise, record all the overridden methods in our set.
+        for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
+             E = MD->end_overridden_methods(); I != E; ++I) {
+          // Keep track of the overridden methods.
+          OverriddenMethods.insert(*I);
+        }
+      }
+    }
+    
+    // Now go through the methods and zero out all the ones we know are 
+    // overridden.
+    for (size_t i = 0, e = MethodsSize; i != e; ++i) {
+      if (OverriddenMethods.count(Methods[i]))
+        Methods[i] = 0;
+    }
+    
+  }
+}
+
+bool Sema::RequireNonAbstractType(SourceLocation Loc, QualType T, 
+                                  unsigned DiagID, AbstractDiagSelID SelID,
+                                  const CXXRecordDecl *CurrentRD) {
+  
+  if (!getLangOptions().CPlusPlus)
+    return false;
+  
+  if (const ArrayType *AT = Context.getAsArrayType(T))
+    return RequireNonAbstractType(Loc, AT->getElementType(), DiagID, SelID,
+                                  CurrentRD);
+  
+  if (const PointerType *PT = T->getAsPointerType()) {
+    // Find the innermost pointer type.
+    while (const PointerType *T = PT->getPointeeType()->getAsPointerType())
+      PT = T;
+    
+    if (const ArrayType *AT = Context.getAsArrayType(PT->getPointeeType()))
+      return RequireNonAbstractType(Loc, AT->getElementType(), DiagID, SelID,
+                                    CurrentRD);
+  }
+  
+  const RecordType *RT = T->getAsRecordType();
+  if (!RT)
+    return false;
+  
+  const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
+  if (!RD)
+    return false;
+
+  if (CurrentRD && CurrentRD != RD)
+    return false;
+  
+  if (!RD->isAbstract())
+    return false;
+  
+  Diag(Loc, DiagID) << RD->getDeclName() << SelID;
+  
+  // Check if we've already emitted the list of pure virtual functions for this
+  // class.
+  if (PureVirtualClassDiagSet && PureVirtualClassDiagSet->count(RD))
+    return true;
+  
+  PureVirtualMethodCollector Collector(Context, RD);
+  
+  for (PureVirtualMethodCollector::MethodList::const_iterator I = 
+       Collector.methods_begin(), E = Collector.methods_end(); I != E; ++I) {
+    const CXXMethodDecl *MD = *I;
+    
+    Diag(MD->getLocation(), diag::note_pure_virtual_function) << 
+      MD->getDeclName();
+  }
+
+  if (!PureVirtualClassDiagSet)
+    PureVirtualClassDiagSet.reset(new RecordDeclSetTy);
+  PureVirtualClassDiagSet->insert(RD);
+  
+  return true;
+}
+
+namespace {
+  class VISIBILITY_HIDDEN AbstractClassUsageDiagnoser 
+    : public DeclVisitor<AbstractClassUsageDiagnoser, bool> {
+    Sema &SemaRef;
+    CXXRecordDecl *AbstractClass;
+  
+    bool VisitDeclContext(const DeclContext *DC) {
+      bool Invalid = false;
+
+      for (CXXRecordDecl::decl_iterator I = DC->decls_begin(SemaRef.Context),
+           E = DC->decls_end(SemaRef.Context); I != E; ++I)
+        Invalid |= Visit(*I);
+
+      return Invalid;
+    }
+      
+  public:
+    AbstractClassUsageDiagnoser(Sema& SemaRef, CXXRecordDecl *ac)
+      : SemaRef(SemaRef), AbstractClass(ac) {
+        Visit(SemaRef.Context.getTranslationUnitDecl());
+    }
+
+    bool VisitFunctionDecl(const FunctionDecl *FD) {
+      if (FD->isThisDeclarationADefinition()) {
+        // No need to do the check if we're in a definition, because it requires
+        // that the return/param types are complete.
+        // because that requires 
+        return VisitDeclContext(FD);
+      }
+      
+      // Check the return type.
+      QualType RTy = FD->getType()->getAsFunctionType()->getResultType();
+      bool Invalid = 
+        SemaRef.RequireNonAbstractType(FD->getLocation(), RTy,
+                                       diag::err_abstract_type_in_decl,
+                                       Sema::AbstractReturnType,
+                                       AbstractClass);
+
+      for (FunctionDecl::param_const_iterator I = FD->param_begin(), 
+           E = FD->param_end(); I != E; ++I) {
+        const ParmVarDecl *VD = *I;
+        Invalid |= 
+          SemaRef.RequireNonAbstractType(VD->getLocation(),
+                                         VD->getOriginalType(), 
+                                         diag::err_abstract_type_in_decl, 
+                                         Sema::AbstractParamType,
+                                         AbstractClass);
+      }
+
+      return Invalid;
+    }
+    
+    bool VisitDecl(const Decl* D) {
+      if (const DeclContext *DC = dyn_cast<DeclContext>(D))
+        return VisitDeclContext(DC);
+      
+      return false;
+    }
+  };
+}
+
+void Sema::ActOnFinishCXXMemberSpecification(Scope* S, SourceLocation RLoc,
+                                             DeclPtrTy TagDecl,
+                                             SourceLocation LBrac,
+                                             SourceLocation RBrac) {
+  AdjustDeclIfTemplate(TagDecl);
+  ActOnFields(S, RLoc, TagDecl,
+              (DeclPtrTy*)FieldCollector->getCurFields(),
+              FieldCollector->getCurNumFields(), LBrac, RBrac, 0);
+
+  CXXRecordDecl *RD = cast<CXXRecordDecl>(TagDecl.getAs<Decl>());
+  if (!RD->isAbstract()) {
+    // Collect all the pure virtual methods and see if this is an abstract
+    // class after all.
+    PureVirtualMethodCollector Collector(Context, RD);
+    if (!Collector.empty()) 
+      RD->setAbstract(true);
+  }
+  
+  if (RD->isAbstract()) 
+    AbstractClassUsageDiagnoser(*this, RD);
+    
+  if (RD->hasTrivialConstructor() || RD->hasTrivialDestructor()) {
+    for (RecordDecl::field_iterator i = RD->field_begin(Context), 
+         e = RD->field_end(Context); i != e; ++i) {
+      // All the nonstatic data members must have trivial constructors.
+      QualType FTy = i->getType();
+      while (const ArrayType *AT = Context.getAsArrayType(FTy))
+        FTy = AT->getElementType();
+      
+      if (const RecordType *RT = FTy->getAsRecordType()) {
+        CXXRecordDecl *FieldRD = cast<CXXRecordDecl>(RT->getDecl());
+        
+        if (!FieldRD->hasTrivialConstructor())
+          RD->setHasTrivialConstructor(false);
+        if (!FieldRD->hasTrivialDestructor())
+          RD->setHasTrivialDestructor(false);
+        
+        // If RD has neither a trivial constructor nor a trivial destructor
+        // we don't need to continue checking.
+        if (!RD->hasTrivialConstructor() && !RD->hasTrivialDestructor())
+          break;
+      }
+    }
+  }
+      
+  if (!RD->isDependentType())
+    AddImplicitlyDeclaredMembersToClass(RD);
+}
+
+/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared
+/// special functions, such as the default constructor, copy
+/// constructor, or destructor, to the given C++ class (C++
+/// [special]p1).  This routine can only be executed just before the
+/// definition of the class is complete.
+void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
+  QualType ClassType = Context.getTypeDeclType(ClassDecl);
+  ClassType = Context.getCanonicalType(ClassType);
+
+  // FIXME: Implicit declarations have exception specifications, which are
+  // the union of the specifications of the implicitly called functions.
+
+  if (!ClassDecl->hasUserDeclaredConstructor()) {
+    // C++ [class.ctor]p5:
+    //   A default constructor for a class X is a constructor of class X
+    //   that can be called without an argument. If there is no
+    //   user-declared constructor for class X, a default constructor is
+    //   implicitly declared. An implicitly-declared default constructor
+    //   is an inline public member of its class.
+    DeclarationName Name 
+      = Context.DeclarationNames.getCXXConstructorName(ClassType);
+    CXXConstructorDecl *DefaultCon = 
+      CXXConstructorDecl::Create(Context, ClassDecl,
+                                 ClassDecl->getLocation(), Name,
+                                 Context.getFunctionType(Context.VoidTy,
+                                                         0, 0, false, 0),
+                                 /*isExplicit=*/false,
+                                 /*isInline=*/true,
+                                 /*isImplicitlyDeclared=*/true);
+    DefaultCon->setAccess(AS_public);
+    DefaultCon->setImplicit();
+    ClassDecl->addDecl(Context, DefaultCon);
+
+    // Notify the class that we've added a constructor.
+    ClassDecl->addedConstructor(Context, DefaultCon);
+  }
+
+  if (!ClassDecl->hasUserDeclaredCopyConstructor()) {
+    // C++ [class.copy]p4:
+    //   If the class definition does not explicitly declare a copy
+    //   constructor, one is declared implicitly.
+
+    // C++ [class.copy]p5:
+    //   The implicitly-declared copy constructor for a class X will
+    //   have the form
+    //
+    //       X::X(const X&)
+    //
+    //   if
+    bool HasConstCopyConstructor = true;
+
+    //     -- each direct or virtual base class B of X has a copy
+    //        constructor whose first parameter is of type const B& or
+    //        const volatile B&, and
+    for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin();
+         HasConstCopyConstructor && Base != ClassDecl->bases_end(); ++Base) {
+      const CXXRecordDecl *BaseClassDecl
+        = cast<CXXRecordDecl>(Base->getType()->getAsRecordType()->getDecl());
+      HasConstCopyConstructor 
+        = BaseClassDecl->hasConstCopyConstructor(Context);
+    }
+
+    //     -- for all the nonstatic data members of X that are of a
+    //        class type M (or array thereof), each such class type
+    //        has a copy constructor whose first parameter is of type
+    //        const M& or const volatile M&.
+    for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(Context);
+         HasConstCopyConstructor && Field != ClassDecl->field_end(Context);
+         ++Field) {
+      QualType FieldType = (*Field)->getType();
+      if (const ArrayType *Array = Context.getAsArrayType(FieldType))
+        FieldType = Array->getElementType();
+      if (const RecordType *FieldClassType = FieldType->getAsRecordType()) {
+        const CXXRecordDecl *FieldClassDecl 
+          = cast<CXXRecordDecl>(FieldClassType->getDecl());
+        HasConstCopyConstructor 
+          = FieldClassDecl->hasConstCopyConstructor(Context);
+      }
+    }
+
+    //   Otherwise, the implicitly declared copy constructor will have
+    //   the form
+    //
+    //       X::X(X&)
+    QualType ArgType = ClassType;
+    if (HasConstCopyConstructor)
+      ArgType = ArgType.withConst();
+    ArgType = Context.getLValueReferenceType(ArgType);
+
+    //   An implicitly-declared copy constructor is an inline public
+    //   member of its class.
+    DeclarationName Name 
+      = Context.DeclarationNames.getCXXConstructorName(ClassType);
+    CXXConstructorDecl *CopyConstructor
+      = CXXConstructorDecl::Create(Context, ClassDecl,
+                                   ClassDecl->getLocation(), Name,
+                                   Context.getFunctionType(Context.VoidTy,
+                                                           &ArgType, 1,
+                                                           false, 0),
+                                   /*isExplicit=*/false,
+                                   /*isInline=*/true,
+                                   /*isImplicitlyDeclared=*/true);
+    CopyConstructor->setAccess(AS_public);
+    CopyConstructor->setImplicit();
+
+    // Add the parameter to the constructor.
+    ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyConstructor,
+                                                 ClassDecl->getLocation(),
+                                                 /*IdentifierInfo=*/0,
+                                                 ArgType, VarDecl::None, 0);
+    CopyConstructor->setParams(Context, &FromParam, 1);
+
+    ClassDecl->addedConstructor(Context, CopyConstructor);
+    ClassDecl->addDecl(Context, CopyConstructor);
+  }
+
+  if (!ClassDecl->hasUserDeclaredCopyAssignment()) {
+    // Note: The following rules are largely analoguous to the copy
+    // constructor rules. Note that virtual bases are not taken into account
+    // for determining the argument type of the operator. Note also that
+    // operators taking an object instead of a reference are allowed.
+    //
+    // C++ [class.copy]p10:
+    //   If the class definition does not explicitly declare a copy
+    //   assignment operator, one is declared implicitly.
+    //   The implicitly-defined copy assignment operator for a class X
+    //   will have the form
+    //
+    //       X& X::operator=(const X&)
+    //
+    //   if
+    bool HasConstCopyAssignment = true;
+
+    //       -- each direct base class B of X has a copy assignment operator
+    //          whose parameter is of type const B&, const volatile B& or B,
+    //          and
+    for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin();
+         HasConstCopyAssignment && Base != ClassDecl->bases_end(); ++Base) {
+      const CXXRecordDecl *BaseClassDecl
+        = cast<CXXRecordDecl>(Base->getType()->getAsRecordType()->getDecl());
+      HasConstCopyAssignment = BaseClassDecl->hasConstCopyAssignment(Context);
+    }
+
+    //       -- for all the nonstatic data members of X that are of a class
+    //          type M (or array thereof), each such class type has a copy
+    //          assignment operator whose parameter is of type const M&,
+    //          const volatile M& or M.
+    for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(Context);
+         HasConstCopyAssignment && Field != ClassDecl->field_end(Context);
+         ++Field) {
+      QualType FieldType = (*Field)->getType();
+      if (const ArrayType *Array = Context.getAsArrayType(FieldType))
+        FieldType = Array->getElementType();
+      if (const RecordType *FieldClassType = FieldType->getAsRecordType()) {
+        const CXXRecordDecl *FieldClassDecl
+          = cast<CXXRecordDecl>(FieldClassType->getDecl());
+        HasConstCopyAssignment
+          = FieldClassDecl->hasConstCopyAssignment(Context);
+      }
+    }
+
+    //   Otherwise, the implicitly declared copy assignment operator will
+    //   have the form
+    //
+    //       X& X::operator=(X&)
+    QualType ArgType = ClassType;
+    QualType RetType = Context.getLValueReferenceType(ArgType);
+    if (HasConstCopyAssignment)
+      ArgType = ArgType.withConst();
+    ArgType = Context.getLValueReferenceType(ArgType);
+
+    //   An implicitly-declared copy assignment operator is an inline public
+    //   member of its class.
+    DeclarationName Name =
+      Context.DeclarationNames.getCXXOperatorName(OO_Equal);
+    CXXMethodDecl *CopyAssignment =
+      CXXMethodDecl::Create(Context, ClassDecl, ClassDecl->getLocation(), Name,
+                            Context.getFunctionType(RetType, &ArgType, 1,
+                                                    false, 0),
+                            /*isStatic=*/false, /*isInline=*/true);
+    CopyAssignment->setAccess(AS_public);
+    CopyAssignment->setImplicit();
+
+    // Add the parameter to the operator.
+    ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyAssignment,
+                                                 ClassDecl->getLocation(),
+                                                 /*IdentifierInfo=*/0,
+                                                 ArgType, VarDecl::None, 0);
+    CopyAssignment->setParams(Context, &FromParam, 1);
+
+    // Don't call addedAssignmentOperator. There is no way to distinguish an
+    // implicit from an explicit assignment operator.
+    ClassDecl->addDecl(Context, CopyAssignment);
+  }
+
+  if (!ClassDecl->hasUserDeclaredDestructor()) {
+    // C++ [class.dtor]p2:
+    //   If a class has no user-declared destructor, a destructor is
+    //   declared implicitly. An implicitly-declared destructor is an
+    //   inline public member of its class.
+    DeclarationName Name 
+      = Context.DeclarationNames.getCXXDestructorName(ClassType);
+    CXXDestructorDecl *Destructor 
+      = CXXDestructorDecl::Create(Context, ClassDecl,
+                                  ClassDecl->getLocation(), Name,
+                                  Context.getFunctionType(Context.VoidTy,
+                                                          0, 0, false, 0),
+                                  /*isInline=*/true,
+                                  /*isImplicitlyDeclared=*/true);
+    Destructor->setAccess(AS_public);
+    Destructor->setImplicit();
+    ClassDecl->addDecl(Context, Destructor);
+  }
+}
+
+void Sema::ActOnReenterTemplateScope(Scope *S, DeclPtrTy TemplateD) {
+  TemplateDecl *Template = TemplateD.getAs<TemplateDecl>();
+  if (!Template)
+    return;
+
+  TemplateParameterList *Params = Template->getTemplateParameters();
+  for (TemplateParameterList::iterator Param = Params->begin(),
+                                    ParamEnd = Params->end();
+       Param != ParamEnd; ++Param) {
+    NamedDecl *Named = cast<NamedDecl>(*Param);
+    if (Named->getDeclName()) {
+      S->AddDecl(DeclPtrTy::make(Named));
+      IdResolver.AddDecl(Named);
+    }
+  }
+}
+
+/// ActOnStartDelayedCXXMethodDeclaration - We have completed
+/// parsing a top-level (non-nested) C++ class, and we are now
+/// parsing those parts of the given Method declaration that could
+/// not be parsed earlier (C++ [class.mem]p2), such as default
+/// arguments. This action should enter the scope of the given
+/// Method declaration as if we had just parsed the qualified method
+/// name. However, it should not bring the parameters into scope;
+/// that will be performed by ActOnDelayedCXXMethodParameter.
+void Sema::ActOnStartDelayedCXXMethodDeclaration(Scope *S, DeclPtrTy MethodD) {
+  CXXScopeSpec SS;
+  FunctionDecl *Method = cast<FunctionDecl>(MethodD.getAs<Decl>());
+  QualType ClassTy 
+    = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext()));
+  SS.setScopeRep(
+    NestedNameSpecifier::Create(Context, 0, false, ClassTy.getTypePtr()));
+  ActOnCXXEnterDeclaratorScope(S, SS);
+}
+
+/// ActOnDelayedCXXMethodParameter - We've already started a delayed
+/// C++ method declaration. We're (re-)introducing the given
+/// function parameter into scope for use in parsing later parts of
+/// the method declaration. For example, we could see an
+/// ActOnParamDefaultArgument event for this parameter.
+void Sema::ActOnDelayedCXXMethodParameter(Scope *S, DeclPtrTy ParamD) {
+  ParmVarDecl *Param = cast<ParmVarDecl>(ParamD.getAs<Decl>());
+
+  // If this parameter has an unparsed default argument, clear it out
+  // to make way for the parsed default argument.
+  if (Param->hasUnparsedDefaultArg())
+    Param->setDefaultArg(0);
+
+  S->AddDecl(DeclPtrTy::make(Param));
+  if (Param->getDeclName())
+    IdResolver.AddDecl(Param);
+}
+
+/// ActOnFinishDelayedCXXMethodDeclaration - We have finished
+/// processing the delayed method declaration for Method. The method
+/// declaration is now considered finished. There may be a separate
+/// ActOnStartOfFunctionDef action later (not necessarily
+/// immediately!) for this method, if it was also defined inside the
+/// class body.
+void Sema::ActOnFinishDelayedCXXMethodDeclaration(Scope *S, DeclPtrTy MethodD) {
+  FunctionDecl *Method = cast<FunctionDecl>(MethodD.getAs<Decl>());
+  CXXScopeSpec SS;
+  QualType ClassTy 
+    = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext()));
+  SS.setScopeRep(
+    NestedNameSpecifier::Create(Context, 0, false, ClassTy.getTypePtr()));
+  ActOnCXXExitDeclaratorScope(S, SS);
+
+  // Now that we have our default arguments, check the constructor
+  // again. It could produce additional diagnostics or affect whether
+  // the class has implicitly-declared destructors, among other
+  // things.
+  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Method))
+    CheckConstructor(Constructor);
+
+  // Check the default arguments, which we may have added.
+  if (!Method->isInvalidDecl())
+    CheckCXXDefaultArguments(Method);
+}
+
+/// CheckConstructorDeclarator - Called by ActOnDeclarator to check
+/// the well-formedness of the constructor declarator @p D with type @p
+/// R. If there are any errors in the declarator, this routine will
+/// emit diagnostics and set the invalid bit to true.  In any case, the type
+/// will be updated to reflect a well-formed type for the constructor and
+/// returned.
+QualType Sema::CheckConstructorDeclarator(Declarator &D, QualType R,
+                                          FunctionDecl::StorageClass &SC) {
+  bool isVirtual = D.getDeclSpec().isVirtualSpecified();
+
+  // C++ [class.ctor]p3:
+  //   A constructor shall not be virtual (10.3) or static (9.4). A
+  //   constructor can be invoked for a const, volatile or const
+  //   volatile object. A constructor shall not be declared const,
+  //   volatile, or const volatile (9.3.2).
+  if (isVirtual) {
+    if (!D.isInvalidType())
+      Diag(D.getIdentifierLoc(), diag::err_constructor_cannot_be)
+        << "virtual" << SourceRange(D.getDeclSpec().getVirtualSpecLoc())
+        << SourceRange(D.getIdentifierLoc());
+    D.setInvalidType();
+  }
+  if (SC == FunctionDecl::Static) {
+    if (!D.isInvalidType())
+      Diag(D.getIdentifierLoc(), diag::err_constructor_cannot_be)
+        << "static" << SourceRange(D.getDeclSpec().getStorageClassSpecLoc())
+        << SourceRange(D.getIdentifierLoc());
+    D.setInvalidType();
+    SC = FunctionDecl::None;
+  }
+  
+  DeclaratorChunk::FunctionTypeInfo &FTI = D.getTypeObject(0).Fun;
+  if (FTI.TypeQuals != 0) {
+    if (FTI.TypeQuals & QualType::Const)
+      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_constructor)
+        << "const" << SourceRange(D.getIdentifierLoc());
+    if (FTI.TypeQuals & QualType::Volatile)
+      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_constructor)
+        << "volatile" << SourceRange(D.getIdentifierLoc());
+    if (FTI.TypeQuals & QualType::Restrict)
+      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_constructor)
+        << "restrict" << SourceRange(D.getIdentifierLoc());
+  }
+      
+  // Rebuild the function type "R" without any type qualifiers (in
+  // case any of the errors above fired) and with "void" as the
+  // return type, since constructors don't have return types. We
+  // *always* have to do this, because GetTypeForDeclarator will
+  // put in a result type of "int" when none was specified.
+  const FunctionProtoType *Proto = R->getAsFunctionProtoType();
+  return Context.getFunctionType(Context.VoidTy, Proto->arg_type_begin(),
+                                 Proto->getNumArgs(),
+                                 Proto->isVariadic(), 0);
+}
+
+/// CheckConstructor - Checks a fully-formed constructor for
+/// well-formedness, issuing any diagnostics required. Returns true if
+/// the constructor declarator is invalid.
+void Sema::CheckConstructor(CXXConstructorDecl *Constructor) {
+  CXXRecordDecl *ClassDecl 
+    = dyn_cast<CXXRecordDecl>(Constructor->getDeclContext());
+  if (!ClassDecl)
+    return Constructor->setInvalidDecl();
+
+  // C++ [class.copy]p3:
+  //   A declaration of a constructor for a class X is ill-formed if
+  //   its first parameter is of type (optionally cv-qualified) X and
+  //   either there are no other parameters or else all other
+  //   parameters have default arguments.
+  if (!Constructor->isInvalidDecl() &&
+      ((Constructor->getNumParams() == 1) || 
+       (Constructor->getNumParams() > 1 && 
+        Constructor->getParamDecl(1)->getDefaultArg() != 0))) {
+    QualType ParamType = Constructor->getParamDecl(0)->getType();
+    QualType ClassTy = Context.getTagDeclType(ClassDecl);
+    if (Context.getCanonicalType(ParamType).getUnqualifiedType() == ClassTy) {
+      SourceLocation ParamLoc = Constructor->getParamDecl(0)->getLocation();
+      Diag(ParamLoc, diag::err_constructor_byvalue_arg)
+        << CodeModificationHint::CreateInsertion(ParamLoc, " const &");
+      Constructor->setInvalidDecl();
+    }
+  }
+  
+  // Notify the class that we've added a constructor.
+  ClassDecl->addedConstructor(Context, Constructor);
+}
+
+static inline bool 
+FTIHasSingleVoidArgument(DeclaratorChunk::FunctionTypeInfo &FTI) {
+  return (FTI.NumArgs == 1 && !FTI.isVariadic && FTI.ArgInfo[0].Ident == 0 &&
+          FTI.ArgInfo[0].Param &&
+          FTI.ArgInfo[0].Param.getAs<ParmVarDecl>()->getType()->isVoidType());
+}
+
+/// CheckDestructorDeclarator - Called by ActOnDeclarator to check
+/// the well-formednes of the destructor declarator @p D with type @p
+/// R. If there are any errors in the declarator, this routine will
+/// emit diagnostics and set the declarator to invalid.  Even if this happens,
+/// will be updated to reflect a well-formed type for the destructor and
+/// returned.
+QualType Sema::CheckDestructorDeclarator(Declarator &D,
+                                         FunctionDecl::StorageClass& SC) {
+  // C++ [class.dtor]p1:
+  //   [...] A typedef-name that names a class is a class-name
+  //   (7.1.3); however, a typedef-name that names a class shall not
+  //   be used as the identifier in the declarator for a destructor
+  //   declaration.
+  QualType DeclaratorType = QualType::getFromOpaquePtr(D.getDeclaratorIdType());
+  if (isa<TypedefType>(DeclaratorType)) {
+    Diag(D.getIdentifierLoc(), diag::err_destructor_typedef_name)
+      << DeclaratorType;
+    D.setInvalidType();
+  }
+
+  // C++ [class.dtor]p2:
+  //   A destructor is used to destroy objects of its class type. A
+  //   destructor takes no parameters, and no return type can be
+  //   specified for it (not even void). The address of a destructor
+  //   shall not be taken. A destructor shall not be static. A
+  //   destructor can be invoked for a const, volatile or const
+  //   volatile object. A destructor shall not be declared const,
+  //   volatile or const volatile (9.3.2).
+  if (SC == FunctionDecl::Static) {
+    if (!D.isInvalidType())
+      Diag(D.getIdentifierLoc(), diag::err_destructor_cannot_be)
+        << "static" << SourceRange(D.getDeclSpec().getStorageClassSpecLoc())
+        << SourceRange(D.getIdentifierLoc());
+    SC = FunctionDecl::None;
+    D.setInvalidType();
+  }
+  if (D.getDeclSpec().hasTypeSpecifier() && !D.isInvalidType()) {
+    // Destructors don't have return types, but the parser will
+    // happily parse something like:
+    //
+    //   class X {
+    //     float ~X();
+    //   };
+    //
+    // The return type will be eliminated later.
+    Diag(D.getIdentifierLoc(), diag::err_destructor_return_type)
+      << SourceRange(D.getDeclSpec().getTypeSpecTypeLoc())
+      << SourceRange(D.getIdentifierLoc());
+  }
+  
+  DeclaratorChunk::FunctionTypeInfo &FTI = D.getTypeObject(0).Fun;
+  if (FTI.TypeQuals != 0 && !D.isInvalidType()) {
+    if (FTI.TypeQuals & QualType::Const)
+      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_destructor)
+        << "const" << SourceRange(D.getIdentifierLoc());
+    if (FTI.TypeQuals & QualType::Volatile)
+      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_destructor)
+        << "volatile" << SourceRange(D.getIdentifierLoc());
+    if (FTI.TypeQuals & QualType::Restrict)
+      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_destructor)
+        << "restrict" << SourceRange(D.getIdentifierLoc());
+    D.setInvalidType();
+  }
+
+  // Make sure we don't have any parameters.
+  if (FTI.NumArgs > 0 && !FTIHasSingleVoidArgument(FTI)) {
+    Diag(D.getIdentifierLoc(), diag::err_destructor_with_params);
+
+    // Delete the parameters.
+    FTI.freeArgs();
+    D.setInvalidType();
+  }
+
+  // Make sure the destructor isn't variadic.  
+  if (FTI.isVariadic) {
+    Diag(D.getIdentifierLoc(), diag::err_destructor_variadic);
+    D.setInvalidType();
+  }
+
+  // Rebuild the function type "R" without any type qualifiers or
+  // parameters (in case any of the errors above fired) and with
+  // "void" as the return type, since destructors don't have return
+  // types. We *always* have to do this, because GetTypeForDeclarator
+  // will put in a result type of "int" when none was specified.
+  return Context.getFunctionType(Context.VoidTy, 0, 0, false, 0);
+}
+
+/// CheckConversionDeclarator - Called by ActOnDeclarator to check the
+/// well-formednes of the conversion function declarator @p D with
+/// type @p R. If there are any errors in the declarator, this routine
+/// will emit diagnostics and return true. Otherwise, it will return
+/// false. Either way, the type @p R will be updated to reflect a
+/// well-formed type for the conversion operator.
+void Sema::CheckConversionDeclarator(Declarator &D, QualType &R,
+                                     FunctionDecl::StorageClass& SC) {
+  // C++ [class.conv.fct]p1:
+  //   Neither parameter types nor return type can be specified. The
+  //   type of a conversion function (8.3.5) is “function taking no
+  //   parameter returning conversion-type-id.” 
+  if (SC == FunctionDecl::Static) {
+    if (!D.isInvalidType())
+      Diag(D.getIdentifierLoc(), diag::err_conv_function_not_member)
+        << "static" << SourceRange(D.getDeclSpec().getStorageClassSpecLoc())
+        << SourceRange(D.getIdentifierLoc());
+    D.setInvalidType();
+    SC = FunctionDecl::None;
+  }
+  if (D.getDeclSpec().hasTypeSpecifier() && !D.isInvalidType()) {
+    // Conversion functions don't have return types, but the parser will
+    // happily parse something like:
+    //
+    //   class X {
+    //     float operator bool();
+    //   };
+    //
+    // The return type will be changed later anyway.
+    Diag(D.getIdentifierLoc(), diag::err_conv_function_return_type)
+      << SourceRange(D.getDeclSpec().getTypeSpecTypeLoc())
+      << SourceRange(D.getIdentifierLoc());
+  }
+
+  // Make sure we don't have any parameters.
+  if (R->getAsFunctionProtoType()->getNumArgs() > 0) {
+    Diag(D.getIdentifierLoc(), diag::err_conv_function_with_params);
+
+    // Delete the parameters.
+    D.getTypeObject(0).Fun.freeArgs();
+    D.setInvalidType();
+  }
+
+  // Make sure the conversion function isn't variadic.  
+  if (R->getAsFunctionProtoType()->isVariadic() && !D.isInvalidType()) {
+    Diag(D.getIdentifierLoc(), diag::err_conv_function_variadic);
+    D.setInvalidType();
+  }
+
+  // C++ [class.conv.fct]p4:
+  //   The conversion-type-id shall not represent a function type nor
+  //   an array type.
+  QualType ConvType = QualType::getFromOpaquePtr(D.getDeclaratorIdType());
+  if (ConvType->isArrayType()) {
+    Diag(D.getIdentifierLoc(), diag::err_conv_function_to_array);
+    ConvType = Context.getPointerType(ConvType);
+    D.setInvalidType();
+  } else if (ConvType->isFunctionType()) {
+    Diag(D.getIdentifierLoc(), diag::err_conv_function_to_function);
+    ConvType = Context.getPointerType(ConvType);
+    D.setInvalidType();
+  }
+
+  // Rebuild the function type "R" without any parameters (in case any
+  // of the errors above fired) and with the conversion type as the
+  // return type. 
+  R = Context.getFunctionType(ConvType, 0, 0, false, 
+                              R->getAsFunctionProtoType()->getTypeQuals());
+
+  // C++0x explicit conversion operators.
+  if (D.getDeclSpec().isExplicitSpecified() && !getLangOptions().CPlusPlus0x)
+    Diag(D.getDeclSpec().getExplicitSpecLoc(), 
+         diag::warn_explicit_conversion_functions)
+      << SourceRange(D.getDeclSpec().getExplicitSpecLoc());
+}
+
+/// ActOnConversionDeclarator - Called by ActOnDeclarator to complete
+/// the declaration of the given C++ conversion function. This routine
+/// is responsible for recording the conversion function in the C++
+/// class, if possible.
+Sema::DeclPtrTy Sema::ActOnConversionDeclarator(CXXConversionDecl *Conversion) {
+  assert(Conversion && "Expected to receive a conversion function declaration");
+
+  // Set the lexical context of this conversion function
+  Conversion->setLexicalDeclContext(CurContext);
+
+  CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(Conversion->getDeclContext());
+
+  // Make sure we aren't redeclaring the conversion function.
+  QualType ConvType = Context.getCanonicalType(Conversion->getConversionType());
+
+  // C++ [class.conv.fct]p1:
+  //   [...] A conversion function is never used to convert a
+  //   (possibly cv-qualified) object to the (possibly cv-qualified)
+  //   same object type (or a reference to it), to a (possibly
+  //   cv-qualified) base class of that type (or a reference to it),
+  //   or to (possibly cv-qualified) void.
+  // FIXME: Suppress this warning if the conversion function ends up being a
+  // virtual function that overrides a virtual function in a base class.
+  QualType ClassType 
+    = Context.getCanonicalType(Context.getTypeDeclType(ClassDecl));
+  if (const ReferenceType *ConvTypeRef = ConvType->getAsReferenceType())
+    ConvType = ConvTypeRef->getPointeeType();
+  if (ConvType->isRecordType()) {
+    ConvType = Context.getCanonicalType(ConvType).getUnqualifiedType();
+    if (ConvType == ClassType)
+      Diag(Conversion->getLocation(), diag::warn_conv_to_self_not_used)
+        << ClassType;
+    else if (IsDerivedFrom(ClassType, ConvType))
+      Diag(Conversion->getLocation(), diag::warn_conv_to_base_not_used)
+        <<  ClassType << ConvType;
+  } else if (ConvType->isVoidType()) {
+    Diag(Conversion->getLocation(), diag::warn_conv_to_void_not_used)
+      << ClassType << ConvType;
+  }
+
+  if (Conversion->getPreviousDeclaration()) {
+    OverloadedFunctionDecl *Conversions = ClassDecl->getConversionFunctions();
+    for (OverloadedFunctionDecl::function_iterator 
+           Conv = Conversions->function_begin(),
+           ConvEnd = Conversions->function_end();
+         Conv != ConvEnd; ++Conv) {
+      if (*Conv == Conversion->getPreviousDeclaration()) {
+        *Conv = Conversion;
+        return DeclPtrTy::make(Conversion);
+      }
+    }
+    assert(Conversion->isInvalidDecl() && "Conversion should not get here.");
+  } else 
+    ClassDecl->addConversionFunction(Context, Conversion);
+
+  return DeclPtrTy::make(Conversion);
+}
+
+//===----------------------------------------------------------------------===//
+// Namespace Handling
+//===----------------------------------------------------------------------===//
+
+/// ActOnStartNamespaceDef - This is called at the start of a namespace
+/// definition.
+Sema::DeclPtrTy Sema::ActOnStartNamespaceDef(Scope *NamespcScope,
+                                             SourceLocation IdentLoc,
+                                             IdentifierInfo *II,
+                                             SourceLocation LBrace) {
+  NamespaceDecl *Namespc =
+      NamespaceDecl::Create(Context, CurContext, IdentLoc, II);
+  Namespc->setLBracLoc(LBrace);
+
+  Scope *DeclRegionScope = NamespcScope->getParent();
+
+  if (II) {
+    // C++ [namespace.def]p2:
+    // The identifier in an original-namespace-definition shall not have been
+    // previously defined in the declarative region in which the
+    // original-namespace-definition appears. The identifier in an
+    // original-namespace-definition is the name of the namespace. Subsequently
+    // in that declarative region, it is treated as an original-namespace-name.
+
+    NamedDecl *PrevDecl = LookupName(DeclRegionScope, II, LookupOrdinaryName,
+                                     true);
+    
+    if (NamespaceDecl *OrigNS = dyn_cast_or_null<NamespaceDecl>(PrevDecl)) {
+      // This is an extended namespace definition.
+      // Attach this namespace decl to the chain of extended namespace
+      // definitions.
+      OrigNS->setNextNamespace(Namespc);
+      Namespc->setOriginalNamespace(OrigNS->getOriginalNamespace());
+
+      // Remove the previous declaration from the scope.      
+      if (DeclRegionScope->isDeclScope(DeclPtrTy::make(OrigNS))) {
+        IdResolver.RemoveDecl(OrigNS);
+        DeclRegionScope->RemoveDecl(DeclPtrTy::make(OrigNS));
+      }
+    } else if (PrevDecl) {
+      // This is an invalid name redefinition.
+      Diag(Namespc->getLocation(), diag::err_redefinition_different_kind)
+       << Namespc->getDeclName();
+      Diag(PrevDecl->getLocation(), diag::note_previous_definition);
+      Namespc->setInvalidDecl();
+      // Continue on to push Namespc as current DeclContext and return it.
+    } 
+
+    PushOnScopeChains(Namespc, DeclRegionScope);
+  } else {
+    // FIXME: Handle anonymous namespaces
+  }
+
+  // Although we could have an invalid decl (i.e. the namespace name is a
+  // redefinition), push it as current DeclContext and try to continue parsing.
+  // FIXME: We should be able to push Namespc here, so that the each DeclContext
+  // for the namespace has the declarations that showed up in that particular
+  // namespace definition.
+  PushDeclContext(NamespcScope, Namespc);
+  return DeclPtrTy::make(Namespc);
+}
+
+/// ActOnFinishNamespaceDef - This callback is called after a namespace is
+/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef.
+void Sema::ActOnFinishNamespaceDef(DeclPtrTy D, SourceLocation RBrace) {
+  Decl *Dcl = D.getAs<Decl>();
+  NamespaceDecl *Namespc = dyn_cast_or_null<NamespaceDecl>(Dcl);
+  assert(Namespc && "Invalid parameter, expected NamespaceDecl");
+  Namespc->setRBracLoc(RBrace);
+  PopDeclContext();
+}
+
+Sema::DeclPtrTy Sema::ActOnUsingDirective(Scope *S,
+                                          SourceLocation UsingLoc,
+                                          SourceLocation NamespcLoc,
+                                          const CXXScopeSpec &SS,
+                                          SourceLocation IdentLoc,
+                                          IdentifierInfo *NamespcName,
+                                          AttributeList *AttrList) {
+  assert(!SS.isInvalid() && "Invalid CXXScopeSpec.");
+  assert(NamespcName && "Invalid NamespcName.");
+  assert(IdentLoc.isValid() && "Invalid NamespceName location.");
+  assert(S->getFlags() & Scope::DeclScope && "Invalid Scope.");
+
+  UsingDirectiveDecl *UDir = 0;
+
+  // Lookup namespace name.
+  LookupResult R = LookupParsedName(S, &SS, NamespcName,
+                                    LookupNamespaceName, false);
+  if (R.isAmbiguous()) {
+    DiagnoseAmbiguousLookup(R, NamespcName, IdentLoc);
+    return DeclPtrTy();
+  }
+  if (NamedDecl *NS = R) {
+    assert(isa<NamespaceDecl>(NS) && "expected namespace decl");
+    // C++ [namespace.udir]p1:
+    //   A using-directive specifies that the names in the nominated
+    //   namespace can be used in the scope in which the
+    //   using-directive appears after the using-directive. During
+    //   unqualified name lookup (3.4.1), the names appear as if they
+    //   were declared in the nearest enclosing namespace which
+    //   contains both the using-directive and the nominated
+    //   namespace. [Note: in this context, “contains” means “contains
+    //   directly or indirectly”. ]
+
+    // Find enclosing context containing both using-directive and
+    // nominated namespace.
+    DeclContext *CommonAncestor = cast<DeclContext>(NS);
+    while (CommonAncestor && !CommonAncestor->Encloses(CurContext))
+      CommonAncestor = CommonAncestor->getParent();
+
+    UDir = UsingDirectiveDecl::Create(Context, 
+                                      CurContext, UsingLoc,
+                                      NamespcLoc, 
+                                      SS.getRange(),
+                                      (NestedNameSpecifier *)SS.getScopeRep(),
+                                      IdentLoc,
+                                      cast<NamespaceDecl>(NS),
+                                      CommonAncestor);
+    PushUsingDirective(S, UDir);
+  } else {
+    Diag(IdentLoc, diag::err_expected_namespace_name) << SS.getRange();
+  }
+
+  // FIXME: We ignore attributes for now.
+  delete AttrList;
+  return DeclPtrTy::make(UDir);
+}
+
+void Sema::PushUsingDirective(Scope *S, UsingDirectiveDecl *UDir) {
+  // If scope has associated entity, then using directive is at namespace
+  // or translation unit scope. We add UsingDirectiveDecls, into
+  // it's lookup structure.
+  if (DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity()))
+    Ctx->addDecl(Context, UDir);
+  else
+    // Otherwise it is block-sope. using-directives will affect lookup
+    // only to the end of scope.
+    S->PushUsingDirective(DeclPtrTy::make(UDir));
+}
+
+/// getNamespaceDecl - Returns the namespace a decl represents. If the decl
+/// is a namespace alias, returns the namespace it points to.
+static inline NamespaceDecl *getNamespaceDecl(NamedDecl *D) {
+  if (NamespaceAliasDecl *AD = dyn_cast_or_null<NamespaceAliasDecl>(D))
+    return AD->getNamespace();
+  return dyn_cast_or_null<NamespaceDecl>(D);
+}
+
+Sema::DeclPtrTy Sema::ActOnNamespaceAliasDef(Scope *S, 
+                                             SourceLocation NamespaceLoc,
+                                             SourceLocation AliasLoc,
+                                             IdentifierInfo *Alias,
+                                             const CXXScopeSpec &SS,
+                                             SourceLocation IdentLoc,
+                                             IdentifierInfo *Ident) {
+  
+  // Lookup the namespace name.
+  LookupResult R = LookupParsedName(S, &SS, Ident, LookupNamespaceName, false);
+
+  // Check if we have a previous declaration with the same name.
+  if (NamedDecl *PrevDecl = LookupName(S, Alias, LookupOrdinaryName, true)) {
+    if (NamespaceAliasDecl *AD = dyn_cast<NamespaceAliasDecl>(PrevDecl)) {
+      // We already have an alias with the same name that points to the same 
+      // namespace, so don't create a new one.
+      if (!R.isAmbiguous() && AD->getNamespace() == getNamespaceDecl(R))
+        return DeclPtrTy();
+    }
+    
+    unsigned DiagID = isa<NamespaceDecl>(PrevDecl) ? diag::err_redefinition :
+      diag::err_redefinition_different_kind;
+    Diag(AliasLoc, DiagID) << Alias;
+    Diag(PrevDecl->getLocation(), diag::note_previous_definition);
+    return DeclPtrTy();
+  }
+
+  if (R.isAmbiguous()) {
+    DiagnoseAmbiguousLookup(R, Ident, IdentLoc);
+    return DeclPtrTy();
+  }
+  
+  if (!R) {
+    Diag(NamespaceLoc, diag::err_expected_namespace_name) << SS.getRange();
+    return DeclPtrTy();
+  }
+  
+  NamespaceAliasDecl *AliasDecl = 
+    NamespaceAliasDecl::Create(Context, CurContext, NamespaceLoc, AliasLoc, 
+                               Alias, SS.getRange(), 
+                               (NestedNameSpecifier *)SS.getScopeRep(),
+                               IdentLoc, R);
+  
+  CurContext->addDecl(Context, AliasDecl);
+  return DeclPtrTy::make(AliasDecl);
+}
+
+void Sema::InitializeVarWithConstructor(VarDecl *VD, 
+                                        CXXConstructorDecl *Constructor,
+                                        QualType DeclInitType, 
+                                        Expr **Exprs, unsigned NumExprs) {
+  Expr *Temp = CXXConstructExpr::Create(Context, DeclInitType, Constructor, 
+                                        false, Exprs, NumExprs);
+  VD->setInit(Context, Temp);
+}
+
+/// AddCXXDirectInitializerToDecl - This action is called immediately after 
+/// ActOnDeclarator, when a C++ direct initializer is present.
+/// e.g: "int x(1);"
+void Sema::AddCXXDirectInitializerToDecl(DeclPtrTy Dcl,
+                                         SourceLocation LParenLoc,
+                                         MultiExprArg Exprs,
+                                         SourceLocation *CommaLocs,
+                                         SourceLocation RParenLoc) {
+  unsigned NumExprs = Exprs.size();
+  assert(NumExprs != 0 && Exprs.get() && "missing expressions");
+  Decl *RealDecl = Dcl.getAs<Decl>();
+
+  // If there is no declaration, there was an error parsing it.  Just ignore
+  // the initializer.
+  if (RealDecl == 0)
+    return;
+  
+  VarDecl *VDecl = dyn_cast<VarDecl>(RealDecl);
+  if (!VDecl) {
+    Diag(RealDecl->getLocation(), diag::err_illegal_initializer);
+    RealDecl->setInvalidDecl();
+    return;
+  }
+
+  // FIXME: Need to handle dependent types and expressions here.
+
+  // We will treat direct-initialization as a copy-initialization:
+  //    int x(1);  -as-> int x = 1;
+  //    ClassType x(a,b,c); -as-> ClassType x = ClassType(a,b,c);
+  //
+  // Clients that want to distinguish between the two forms, can check for
+  // direct initializer using VarDecl::hasCXXDirectInitializer().
+  // A major benefit is that clients that don't particularly care about which
+  // exactly form was it (like the CodeGen) can handle both cases without
+  // special case code.
+
+  // C++ 8.5p11:
+  // The form of initialization (using parentheses or '=') is generally
+  // insignificant, but does matter when the entity being initialized has a
+  // class type.
+  QualType DeclInitType = VDecl->getType();
+  if (const ArrayType *Array = Context.getAsArrayType(DeclInitType))
+    DeclInitType = Array->getElementType();
+
+  // FIXME: This isn't the right place to complete the type.
+  if (RequireCompleteType(VDecl->getLocation(), VDecl->getType(),
+                          diag::err_typecheck_decl_incomplete_type)) {
+    VDecl->setInvalidDecl();
+    return;
+  }
+
+  if (VDecl->getType()->isRecordType()) {
+    CXXConstructorDecl *Constructor
+      = PerformInitializationByConstructor(DeclInitType,
+                                           (Expr **)Exprs.get(), NumExprs,
+                                           VDecl->getLocation(),
+                                           SourceRange(VDecl->getLocation(),
+                                                       RParenLoc),
+                                           VDecl->getDeclName(),
+                                           IK_Direct);
+    if (!Constructor)
+      RealDecl->setInvalidDecl();
+    else {
+      VDecl->setCXXDirectInitializer(true);
+      InitializeVarWithConstructor(VDecl, Constructor, DeclInitType, 
+                                   (Expr**)Exprs.release(), NumExprs);
+    }
+    return;
+  }
+
+  if (NumExprs > 1) {
+    Diag(CommaLocs[0], diag::err_builtin_direct_init_more_than_one_arg)
+      << SourceRange(VDecl->getLocation(), RParenLoc);
+    RealDecl->setInvalidDecl();
+    return;
+  }
+
+  // Let clients know that initialization was done with a direct initializer.
+  VDecl->setCXXDirectInitializer(true);
+
+  assert(NumExprs == 1 && "Expected 1 expression");
+  // Set the init expression, handles conversions.
+  AddInitializerToDecl(Dcl, ExprArg(*this, Exprs.release()[0]),
+                       /*DirectInit=*/true);
+}
+
+/// PerformInitializationByConstructor - Perform initialization by
+/// constructor (C++ [dcl.init]p14), which may occur as part of
+/// direct-initialization or copy-initialization. We are initializing
+/// an object of type @p ClassType with the given arguments @p
+/// Args. @p Loc is the location in the source code where the
+/// initializer occurs (e.g., a declaration, member initializer,
+/// functional cast, etc.) while @p Range covers the whole
+/// initialization. @p InitEntity is the entity being initialized,
+/// which may by the name of a declaration or a type. @p Kind is the
+/// kind of initialization we're performing, which affects whether
+/// explicit constructors will be considered. When successful, returns
+/// the constructor that will be used to perform the initialization;
+/// when the initialization fails, emits a diagnostic and returns
+/// null.
+CXXConstructorDecl *
+Sema::PerformInitializationByConstructor(QualType ClassType,
+                                         Expr **Args, unsigned NumArgs,
+                                         SourceLocation Loc, SourceRange Range,
+                                         DeclarationName InitEntity,
+                                         InitializationKind Kind) {
+  const RecordType *ClassRec = ClassType->getAsRecordType();
+  assert(ClassRec && "Can only initialize a class type here");
+
+  // C++ [dcl.init]p14: 
+  //
+  //   If the initialization is direct-initialization, or if it is
+  //   copy-initialization where the cv-unqualified version of the
+  //   source type is the same class as, or a derived class of, the
+  //   class of the destination, constructors are considered. The
+  //   applicable constructors are enumerated (13.3.1.3), and the
+  //   best one is chosen through overload resolution (13.3). The
+  //   constructor so selected is called to initialize the object,
+  //   with the initializer expression(s) as its argument(s). If no
+  //   constructor applies, or the overload resolution is ambiguous,
+  //   the initialization is ill-formed.
+  const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassRec->getDecl());
+  OverloadCandidateSet CandidateSet;
+
+  // Add constructors to the overload set.
+  DeclarationName ConstructorName 
+    = Context.DeclarationNames.getCXXConstructorName(
+                       Context.getCanonicalType(ClassType.getUnqualifiedType()));
+  DeclContext::lookup_const_iterator Con, ConEnd;
+  for (llvm::tie(Con, ConEnd) = ClassDecl->lookup(Context, ConstructorName);
+       Con != ConEnd; ++Con) {
+    CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con);
+    if ((Kind == IK_Direct) ||
+        (Kind == IK_Copy && Constructor->isConvertingConstructor()) ||
+        (Kind == IK_Default && Constructor->isDefaultConstructor()))
+      AddOverloadCandidate(Constructor, Args, NumArgs, CandidateSet);
+  }
+
+  // FIXME: When we decide not to synthesize the implicitly-declared
+  // constructors, we'll need to make them appear here.
+
+  OverloadCandidateSet::iterator Best;
+  switch (BestViableFunction(CandidateSet, Best)) {
+  case OR_Success:
+    // We found a constructor. Return it.
+    return cast<CXXConstructorDecl>(Best->Function);
+    
+  case OR_No_Viable_Function:
+    if (InitEntity)
+      Diag(Loc, diag::err_ovl_no_viable_function_in_init)
+        << InitEntity << Range;
+    else
+      Diag(Loc, diag::err_ovl_no_viable_function_in_init)
+        << ClassType << Range;
+    PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false);
+    return 0;
+    
+  case OR_Ambiguous:
+    if (InitEntity)
+      Diag(Loc, diag::err_ovl_ambiguous_init) << InitEntity << Range;
+    else
+      Diag(Loc, diag::err_ovl_ambiguous_init) << ClassType << Range;
+    PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true);
+    return 0;
+
+  case OR_Deleted:
+    if (InitEntity)
+      Diag(Loc, diag::err_ovl_deleted_init)
+        << Best->Function->isDeleted()
+        << InitEntity << Range;
+    else
+      Diag(Loc, diag::err_ovl_deleted_init)
+        << Best->Function->isDeleted()
+        << InitEntity << Range;
+    PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true);
+    return 0;
+  }
+  
+  return 0;
+}
+
+/// CompareReferenceRelationship - Compare the two types T1 and T2 to
+/// determine whether they are reference-related,
+/// reference-compatible, reference-compatible with added
+/// qualification, or incompatible, for use in C++ initialization by
+/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
+/// type, and the first type (T1) is the pointee type of the reference
+/// type being initialized.
+Sema::ReferenceCompareResult 
+Sema::CompareReferenceRelationship(QualType T1, QualType T2, 
+                                   bool& DerivedToBase) {
+  assert(!T1->isReferenceType() &&
+    "T1 must be the pointee type of the reference type");
+  assert(!T2->isReferenceType() && "T2 cannot be a reference type");
+
+  T1 = Context.getCanonicalType(T1);
+  T2 = Context.getCanonicalType(T2);
+  QualType UnqualT1 = T1.getUnqualifiedType();
+  QualType UnqualT2 = T2.getUnqualifiedType();
+
+  // C++ [dcl.init.ref]p4:
+  //   Given types “cv1 T1” and “cv2 T2,” “cv1 T1” is
+  //   reference-related to “cv2 T2” if T1 is the same type as T2, or 
+  //   T1 is a base class of T2.
+  if (UnqualT1 == UnqualT2)
+    DerivedToBase = false;
+  else if (IsDerivedFrom(UnqualT2, UnqualT1))
+    DerivedToBase = true;
+  else
+    return Ref_Incompatible;
+
+  // At this point, we know that T1 and T2 are reference-related (at
+  // least).
+
+  // C++ [dcl.init.ref]p4:
+  //   "cv1 T1” is reference-compatible with “cv2 T2” if T1 is
+  //   reference-related to T2 and cv1 is the same cv-qualification
+  //   as, or greater cv-qualification than, cv2. For purposes of
+  //   overload resolution, cases for which cv1 is greater
+  //   cv-qualification than cv2 are identified as
+  //   reference-compatible with added qualification (see 13.3.3.2).
+  if (T1.getCVRQualifiers() == T2.getCVRQualifiers())
+    return Ref_Compatible;
+  else if (T1.isMoreQualifiedThan(T2))
+    return Ref_Compatible_With_Added_Qualification;
+  else
+    return Ref_Related;
+}
+
+/// CheckReferenceInit - Check the initialization of a reference
+/// variable with the given initializer (C++ [dcl.init.ref]). Init is
+/// the initializer (either a simple initializer or an initializer
+/// list), and DeclType is the type of the declaration. When ICS is
+/// non-null, this routine will compute the implicit conversion
+/// sequence according to C++ [over.ics.ref] and will not produce any
+/// diagnostics; when ICS is null, it will emit diagnostics when any
+/// errors are found. Either way, a return value of true indicates
+/// that there was a failure, a return value of false indicates that
+/// the reference initialization succeeded.
+///
+/// When @p SuppressUserConversions, user-defined conversions are
+/// suppressed.
+/// When @p AllowExplicit, we also permit explicit user-defined
+/// conversion functions.
+/// When @p ForceRValue, we unconditionally treat the initializer as an rvalue.
+bool 
+Sema::CheckReferenceInit(Expr *&Init, QualType DeclType,
+                         ImplicitConversionSequence *ICS,
+                         bool SuppressUserConversions,
+                         bool AllowExplicit, bool ForceRValue) {
+  assert(DeclType->isReferenceType() && "Reference init needs a reference");
+
+  QualType T1 = DeclType->getAsReferenceType()->getPointeeType();
+  QualType T2 = Init->getType();
+
+  // If the initializer is the address of an overloaded function, try
+  // to resolve the overloaded function. If all goes well, T2 is the
+  // type of the resulting function.
+  if (Context.getCanonicalType(T2) == Context.OverloadTy) {
+    FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Init, DeclType, 
+                                                          ICS != 0);
+    if (Fn) {
+      // Since we're performing this reference-initialization for
+      // real, update the initializer with the resulting function.
+      if (!ICS) {
+        if (DiagnoseUseOfDecl(Fn, Init->getSourceRange().getBegin()))
+          return true;
+
+        FixOverloadedFunctionReference(Init, Fn);
+      }
+
+      T2 = Fn->getType();
+    }
+  }
+
+  // Compute some basic properties of the types and the initializer.
+  bool isRValRef = DeclType->isRValueReferenceType();
+  bool DerivedToBase = false;
+  Expr::isLvalueResult InitLvalue = ForceRValue ? Expr::LV_InvalidExpression :
+                                                  Init->isLvalue(Context);
+  ReferenceCompareResult RefRelationship 
+    = CompareReferenceRelationship(T1, T2, DerivedToBase);
+
+  // Most paths end in a failed conversion.
+  if (ICS)
+    ICS->ConversionKind = ImplicitConversionSequence::BadConversion;
+
+  // C++ [dcl.init.ref]p5:
+  //   A reference to type “cv1 T1” is initialized by an expression
+  //   of type “cv2 T2” as follows:
+
+  //     -- If the initializer expression
+
+  // Rvalue references cannot bind to lvalues (N2812).
+  // There is absolutely no situation where they can. In particular, note that
+  // this is ill-formed, even if B has a user-defined conversion to A&&:
+  //   B b;
+  //   A&& r = b;
+  if (isRValRef && InitLvalue == Expr::LV_Valid) {
+    if (!ICS)
+      Diag(Init->getSourceRange().getBegin(), diag::err_lvalue_to_rvalue_ref)
+        << Init->getSourceRange();
+    return true;
+  }
+
+  bool BindsDirectly = false;
+  //       -- is an lvalue (but is not a bit-field), and “cv1 T1” is
+  //          reference-compatible with “cv2 T2,” or
+  //
+  // Note that the bit-field check is skipped if we are just computing
+  // the implicit conversion sequence (C++ [over.best.ics]p2).
+  if (InitLvalue == Expr::LV_Valid && (ICS || !Init->getBitField()) &&
+      RefRelationship >= Ref_Compatible_With_Added_Qualification) {
+    BindsDirectly = true;
+
+    if (ICS) {
+      // C++ [over.ics.ref]p1:
+      //   When a parameter of reference type binds directly (8.5.3)
+      //   to an argument expression, the implicit conversion sequence
+      //   is the identity conversion, unless the argument expression
+      //   has a type that is a derived class of the parameter type,
+      //   in which case the implicit conversion sequence is a
+      //   derived-to-base Conversion (13.3.3.1).
+      ICS->ConversionKind = ImplicitConversionSequence::StandardConversion;
+      ICS->Standard.First = ICK_Identity;
+      ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity;
+      ICS->Standard.Third = ICK_Identity;
+      ICS->Standard.FromTypePtr = T2.getAsOpaquePtr();
+      ICS->Standard.ToTypePtr = T1.getAsOpaquePtr();
+      ICS->Standard.ReferenceBinding = true;
+      ICS->Standard.DirectBinding = true;
+      ICS->Standard.RRefBinding = false;
+      ICS->Standard.CopyConstructor = 0;
+
+      // Nothing more to do: the inaccessibility/ambiguity check for
+      // derived-to-base conversions is suppressed when we're
+      // computing the implicit conversion sequence (C++
+      // [over.best.ics]p2).
+      return false;
+    } else {
+      // Perform the conversion.
+      // FIXME: Binding to a subobject of the lvalue is going to require more
+      // AST annotation than this.
+      ImpCastExprToType(Init, T1, /*isLvalue=*/true);    
+    }
+  }
+
+  //       -- has a class type (i.e., T2 is a class type) and can be
+  //          implicitly converted to an lvalue of type “cv3 T3,”
+  //          where “cv1 T1” is reference-compatible with “cv3 T3”
+  //          92) (this conversion is selected by enumerating the
+  //          applicable conversion functions (13.3.1.6) and choosing
+  //          the best one through overload resolution (13.3)),
+  if (!isRValRef && !SuppressUserConversions && T2->isRecordType()) {
+    // FIXME: Look for conversions in base classes!
+    CXXRecordDecl *T2RecordDecl 
+      = dyn_cast<CXXRecordDecl>(T2->getAsRecordType()->getDecl());
+
+    OverloadCandidateSet CandidateSet;
+    OverloadedFunctionDecl *Conversions 
+      = T2RecordDecl->getConversionFunctions();
+    for (OverloadedFunctionDecl::function_iterator Func 
+           = Conversions->function_begin();
+         Func != Conversions->function_end(); ++Func) {
+      CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func);
+
+      // If the conversion function doesn't return a reference type,
+      // it can't be considered for this conversion.
+      if (Conv->getConversionType()->isLValueReferenceType() &&
+          (AllowExplicit || !Conv->isExplicit()))
+        AddConversionCandidate(Conv, Init, DeclType, CandidateSet);
+    }
+
+    OverloadCandidateSet::iterator Best;
+    switch (BestViableFunction(CandidateSet, Best)) {
+    case OR_Success:
+      // This is a direct binding.
+      BindsDirectly = true;
+
+      if (ICS) {
+        // C++ [over.ics.ref]p1:
+        //
+        //   [...] If the parameter binds directly to the result of
+        //   applying a conversion function to the argument
+        //   expression, the implicit conversion sequence is a
+        //   user-defined conversion sequence (13.3.3.1.2), with the
+        //   second standard conversion sequence either an identity
+        //   conversion or, if the conversion function returns an
+        //   entity of a type that is a derived class of the parameter
+        //   type, a derived-to-base Conversion.
+        ICS->ConversionKind = ImplicitConversionSequence::UserDefinedConversion;
+        ICS->UserDefined.Before = Best->Conversions[0].Standard;
+        ICS->UserDefined.After = Best->FinalConversion;
+        ICS->UserDefined.ConversionFunction = Best->Function;
+        assert(ICS->UserDefined.After.ReferenceBinding &&
+               ICS->UserDefined.After.DirectBinding &&
+               "Expected a direct reference binding!");
+        return false;
+      } else {
+        // Perform the conversion.
+        // FIXME: Binding to a subobject of the lvalue is going to require more
+        // AST annotation than this.
+        ImpCastExprToType(Init, T1, /*isLvalue=*/true);
+      }
+      break;
+
+    case OR_Ambiguous:
+      assert(false && "Ambiguous reference binding conversions not implemented.");
+      return true;
+      
+    case OR_No_Viable_Function:
+    case OR_Deleted:
+      // There was no suitable conversion, or we found a deleted
+      // conversion; continue with other checks.
+      break;
+    }
+  }
+      
+  if (BindsDirectly) {
+    // C++ [dcl.init.ref]p4:
+    //   [...] In all cases where the reference-related or
+    //   reference-compatible relationship of two types is used to
+    //   establish the validity of a reference binding, and T1 is a
+    //   base class of T2, a program that necessitates such a binding
+    //   is ill-formed if T1 is an inaccessible (clause 11) or
+    //   ambiguous (10.2) base class of T2.
+    //
+    // Note that we only check this condition when we're allowed to
+    // complain about errors, because we should not be checking for
+    // ambiguity (or inaccessibility) unless the reference binding
+    // actually happens.
+    if (DerivedToBase) 
+      return CheckDerivedToBaseConversion(T2, T1, 
+                                          Init->getSourceRange().getBegin(),
+                                          Init->getSourceRange());
+    else
+      return false;
+  }
+
+  //     -- Otherwise, the reference shall be to a non-volatile const
+  //        type (i.e., cv1 shall be const), or the reference shall be an
+  //        rvalue reference and the initializer expression shall be an rvalue.
+  if (!isRValRef && T1.getCVRQualifiers() != QualType::Const) {
+    if (!ICS)
+      Diag(Init->getSourceRange().getBegin(),
+           diag::err_not_reference_to_const_init)
+        << T1 << (InitLvalue != Expr::LV_Valid? "temporary" : "value")
+        << T2 << Init->getSourceRange();
+    return true;
+  }
+
+  //       -- If the initializer expression is an rvalue, with T2 a
+  //          class type, and “cv1 T1” is reference-compatible with
+  //          “cv2 T2,” the reference is bound in one of the
+  //          following ways (the choice is implementation-defined):
+  //
+  //          -- The reference is bound to the object represented by
+  //             the rvalue (see 3.10) or to a sub-object within that
+  //             object.
+  //
+  //          -- A temporary of type “cv1 T2” [sic] is created, and
+  //             a constructor is called to copy the entire rvalue
+  //             object into the temporary. The reference is bound to
+  //             the temporary or to a sub-object within the
+  //             temporary.
+  //
+  //          The constructor that would be used to make the copy
+  //          shall be callable whether or not the copy is actually
+  //          done.
+  //
+  // Note that C++0x [dcl.init.ref]p5 takes away this implementation
+  // freedom, so we will always take the first option and never build
+  // a temporary in this case. FIXME: We will, however, have to check
+  // for the presence of a copy constructor in C++98/03 mode.
+  if (InitLvalue != Expr::LV_Valid && T2->isRecordType() &&
+      RefRelationship >= Ref_Compatible_With_Added_Qualification) {
+    if (ICS) {
+      ICS->ConversionKind = ImplicitConversionSequence::StandardConversion;
+      ICS->Standard.First = ICK_Identity;
+      ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity;
+      ICS->Standard.Third = ICK_Identity;
+      ICS->Standard.FromTypePtr = T2.getAsOpaquePtr();
+      ICS->Standard.ToTypePtr = T1.getAsOpaquePtr();
+      ICS->Standard.ReferenceBinding = true;
+      ICS->Standard.DirectBinding = false;
+      ICS->Standard.RRefBinding = isRValRef;
+      ICS->Standard.CopyConstructor = 0;
+    } else {
+      // FIXME: Binding to a subobject of the rvalue is going to require more
+      // AST annotation than this.
+      ImpCastExprToType(Init, T1, /*isLvalue=*/false);
+    }
+    return false;
+  }
+
+  //       -- Otherwise, a temporary of type “cv1 T1” is created and
+  //          initialized from the initializer expression using the
+  //          rules for a non-reference copy initialization (8.5). The
+  //          reference is then bound to the temporary. If T1 is
+  //          reference-related to T2, cv1 must be the same
+  //          cv-qualification as, or greater cv-qualification than,
+  //          cv2; otherwise, the program is ill-formed.
+  if (RefRelationship == Ref_Related) {
+    // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
+    // we would be reference-compatible or reference-compatible with
+    // added qualification. But that wasn't the case, so the reference
+    // initialization fails.
+    if (!ICS)
+      Diag(Init->getSourceRange().getBegin(),
+           diag::err_reference_init_drops_quals)
+        << T1 << (InitLvalue != Expr::LV_Valid? "temporary" : "value")
+        << T2 << Init->getSourceRange();
+    return true;
+  }
+
+  // If at least one of the types is a class type, the types are not
+  // related, and we aren't allowed any user conversions, the
+  // reference binding fails. This case is important for breaking
+  // recursion, since TryImplicitConversion below will attempt to
+  // create a temporary through the use of a copy constructor.
+  if (SuppressUserConversions && RefRelationship == Ref_Incompatible &&
+      (T1->isRecordType() || T2->isRecordType())) {
+    if (!ICS)
+      Diag(Init->getSourceRange().getBegin(),
+           diag::err_typecheck_convert_incompatible)
+        << DeclType << Init->getType() << "initializing" << Init->getSourceRange();
+    return true;
+  }
+
+  // Actually try to convert the initializer to T1.
+  if (ICS) {
+    // C++ [over.ics.ref]p2:
+    // 
+    //   When a parameter of reference type is not bound directly to
+    //   an argument expression, the conversion sequence is the one
+    //   required to convert the argument expression to the
+    //   underlying type of the reference according to
+    //   13.3.3.1. Conceptually, this conversion sequence corresponds
+    //   to copy-initializing a temporary of the underlying type with
+    //   the argument expression. Any difference in top-level
+    //   cv-qualification is subsumed by the initialization itself
+    //   and does not constitute a conversion.
+    *ICS = TryImplicitConversion(Init, T1, SuppressUserConversions);
+    // Of course, that's still a reference binding.
+    if (ICS->ConversionKind == ImplicitConversionSequence::StandardConversion) {
+      ICS->Standard.ReferenceBinding = true;
+      ICS->Standard.RRefBinding = isRValRef;
+    } else if(ICS->ConversionKind ==
+              ImplicitConversionSequence::UserDefinedConversion) {
+      ICS->UserDefined.After.ReferenceBinding = true;
+      ICS->UserDefined.After.RRefBinding = isRValRef;
+    }
+    return ICS->ConversionKind == ImplicitConversionSequence::BadConversion;
+  } else {
+    return PerformImplicitConversion(Init, T1, "initializing");
+  }
+}
+
+/// CheckOverloadedOperatorDeclaration - Check whether the declaration
+/// of this overloaded operator is well-formed. If so, returns false;
+/// otherwise, emits appropriate diagnostics and returns true.
+bool Sema::CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl) {
+  assert(FnDecl && FnDecl->isOverloadedOperator() &&
+         "Expected an overloaded operator declaration");
+
+  OverloadedOperatorKind Op = FnDecl->getOverloadedOperator();
+
+  // C++ [over.oper]p5: 
+  //   The allocation and deallocation functions, operator new,
+  //   operator new[], operator delete and operator delete[], are
+  //   described completely in 3.7.3. The attributes and restrictions
+  //   found in the rest of this subclause do not apply to them unless
+  //   explicitly stated in 3.7.3.
+  // FIXME: Write a separate routine for checking this. For now, just allow it.
+  if (Op == OO_New || Op == OO_Array_New ||
+      Op == OO_Delete || Op == OO_Array_Delete)
+    return false;
+
+  // C++ [over.oper]p6:
+  //   An operator function shall either be a non-static member
+  //   function or be a non-member function and have at least one
+  //   parameter whose type is a class, a reference to a class, an
+  //   enumeration, or a reference to an enumeration.
+  if (CXXMethodDecl *MethodDecl = dyn_cast<CXXMethodDecl>(FnDecl)) {
+    if (MethodDecl->isStatic())
+      return Diag(FnDecl->getLocation(),
+                  diag::err_operator_overload_static) << FnDecl->getDeclName();
+  } else {
+    bool ClassOrEnumParam = false;
+    for (FunctionDecl::param_iterator Param = FnDecl->param_begin(),
+                                   ParamEnd = FnDecl->param_end();
+         Param != ParamEnd; ++Param) {
+      QualType ParamType = (*Param)->getType().getNonReferenceType();
+      if (ParamType->isRecordType() || ParamType->isEnumeralType()) {
+        ClassOrEnumParam = true;
+        break;
+      }
+    }
+
+    if (!ClassOrEnumParam)
+      return Diag(FnDecl->getLocation(),
+                  diag::err_operator_overload_needs_class_or_enum)
+        << FnDecl->getDeclName();
+  }
+
+  // C++ [over.oper]p8:
+  //   An operator function cannot have default arguments (8.3.6),
+  //   except where explicitly stated below.
+  //
+  // Only the function-call operator allows default arguments 
+  // (C++ [over.call]p1).
+  if (Op != OO_Call) {
+    for (FunctionDecl::param_iterator Param = FnDecl->param_begin();
+         Param != FnDecl->param_end(); ++Param) {
+      if ((*Param)->hasUnparsedDefaultArg())
+        return Diag((*Param)->getLocation(), 
+                    diag::err_operator_overload_default_arg)
+          << FnDecl->getDeclName();
+      else if (Expr *DefArg = (*Param)->getDefaultArg())
+        return Diag((*Param)->getLocation(),
+                    diag::err_operator_overload_default_arg)
+          << FnDecl->getDeclName() << DefArg->getSourceRange();
+    }
+  }
+
+  static const bool OperatorUses[NUM_OVERLOADED_OPERATORS][3] = {
+    { false, false, false }
+#define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
+    , { Unary, Binary, MemberOnly }
+#include "clang/Basic/OperatorKinds.def"
+  };
+
+  bool CanBeUnaryOperator = OperatorUses[Op][0];
+  bool CanBeBinaryOperator = OperatorUses[Op][1];
+  bool MustBeMemberOperator = OperatorUses[Op][2];
+
+  // C++ [over.oper]p8:
+  //   [...] Operator functions cannot have more or fewer parameters
+  //   than the number required for the corresponding operator, as
+  //   described in the rest of this subclause.
+  unsigned NumParams = FnDecl->getNumParams() 
+                     + (isa<CXXMethodDecl>(FnDecl)? 1 : 0);
+  if (Op != OO_Call &&
+      ((NumParams == 1 && !CanBeUnaryOperator) ||
+       (NumParams == 2 && !CanBeBinaryOperator) ||
+       (NumParams < 1) || (NumParams > 2))) {
+    // We have the wrong number of parameters.
+    unsigned ErrorKind;
+    if (CanBeUnaryOperator && CanBeBinaryOperator) {
+      ErrorKind = 2;  // 2 -> unary or binary.
+    } else if (CanBeUnaryOperator) {
+      ErrorKind = 0;  // 0 -> unary
+    } else {
+      assert(CanBeBinaryOperator &&
+             "All non-call overloaded operators are unary or binary!");
+      ErrorKind = 1;  // 1 -> binary
+    }
+
+    return Diag(FnDecl->getLocation(), diag::err_operator_overload_must_be)
+      << FnDecl->getDeclName() << NumParams << ErrorKind;
+  }
+
+  // Overloaded operators other than operator() cannot be variadic.
+  if (Op != OO_Call &&
+      FnDecl->getType()->getAsFunctionProtoType()->isVariadic()) {
+    return Diag(FnDecl->getLocation(), diag::err_operator_overload_variadic)
+      << FnDecl->getDeclName();
+  }
+
+  // Some operators must be non-static member functions.
+  if (MustBeMemberOperator && !isa<CXXMethodDecl>(FnDecl)) {
+    return Diag(FnDecl->getLocation(),
+                diag::err_operator_overload_must_be_member)
+      << FnDecl->getDeclName();
+  }
+
+  // C++ [over.inc]p1:
+  //   The user-defined function called operator++ implements the
+  //   prefix and postfix ++ operator. If this function is a member
+  //   function with no parameters, or a non-member function with one
+  //   parameter of class or enumeration type, it defines the prefix
+  //   increment operator ++ for objects of that type. If the function
+  //   is a member function with one parameter (which shall be of type
+  //   int) or a non-member function with two parameters (the second
+  //   of which shall be of type int), it defines the postfix
+  //   increment operator ++ for objects of that type.
+  if ((Op == OO_PlusPlus || Op == OO_MinusMinus) && NumParams == 2) {
+    ParmVarDecl *LastParam = FnDecl->getParamDecl(FnDecl->getNumParams() - 1);
+    bool ParamIsInt = false;
+    if (const BuiltinType *BT = LastParam->getType()->getAsBuiltinType())
+      ParamIsInt = BT->getKind() == BuiltinType::Int;
+
+    if (!ParamIsInt)
+      return Diag(LastParam->getLocation(),
+                  diag::err_operator_overload_post_incdec_must_be_int) 
+        << LastParam->getType() << (Op == OO_MinusMinus);
+  }
+
+  // Notify the class if it got an assignment operator.
+  if (Op == OO_Equal) {
+    // Would have returned earlier otherwise.
+    assert(isa<CXXMethodDecl>(FnDecl) &&
+      "Overloaded = not member, but not filtered.");
+    CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl);
+    Method->getParent()->addedAssignmentOperator(Context, Method);
+  }
+
+  return false;
+}
+
+/// ActOnStartLinkageSpecification - Parsed the beginning of a C++
+/// linkage specification, including the language and (if present)
+/// the '{'. ExternLoc is the location of the 'extern', LangLoc is
+/// the location of the language string literal, which is provided
+/// by Lang/StrSize. LBraceLoc, if valid, provides the location of
+/// the '{' brace. Otherwise, this linkage specification does not
+/// have any braces.
+Sema::DeclPtrTy Sema::ActOnStartLinkageSpecification(Scope *S,
+                                                     SourceLocation ExternLoc,
+                                                     SourceLocation LangLoc,
+                                                     const char *Lang,
+                                                     unsigned StrSize,
+                                                     SourceLocation LBraceLoc) {
+  LinkageSpecDecl::LanguageIDs Language;
+  if (strncmp(Lang, "\"C\"", StrSize) == 0)
+    Language = LinkageSpecDecl::lang_c;
+  else if (strncmp(Lang, "\"C++\"", StrSize) == 0)
+    Language = LinkageSpecDecl::lang_cxx;
+  else {
+    Diag(LangLoc, diag::err_bad_language);
+    return DeclPtrTy();
+  }
+  
+  // FIXME: Add all the various semantics of linkage specifications
+  
+  LinkageSpecDecl *D = LinkageSpecDecl::Create(Context, CurContext,
+                                               LangLoc, Language, 
+                                               LBraceLoc.isValid());
+  CurContext->addDecl(Context, D);
+  PushDeclContext(S, D);
+  return DeclPtrTy::make(D);
+}
+
+/// ActOnFinishLinkageSpecification - Completely the definition of
+/// the C++ linkage specification LinkageSpec. If RBraceLoc is
+/// valid, it's the position of the closing '}' brace in a linkage
+/// specification that uses braces.
+Sema::DeclPtrTy Sema::ActOnFinishLinkageSpecification(Scope *S,
+                                                      DeclPtrTy LinkageSpec,
+                                                      SourceLocation RBraceLoc) {
+  if (LinkageSpec)
+    PopDeclContext();
+  return LinkageSpec;
+}
+
+/// \brief Perform semantic analysis for the variable declaration that
+/// occurs within a C++ catch clause, returning the newly-created
+/// variable.
+VarDecl *Sema::BuildExceptionDeclaration(Scope *S, QualType ExDeclType,
+                                         IdentifierInfo *Name,
+                                         SourceLocation Loc,
+                                         SourceRange Range) {
+  bool Invalid = false;
+
+  // Arrays and functions decay.
+  if (ExDeclType->isArrayType())
+    ExDeclType = Context.getArrayDecayedType(ExDeclType);
+  else if (ExDeclType->isFunctionType())
+    ExDeclType = Context.getPointerType(ExDeclType);
+
+  // C++ 15.3p1: The exception-declaration shall not denote an incomplete type.
+  // The exception-declaration shall not denote a pointer or reference to an
+  // incomplete type, other than [cv] void*.
+  // N2844 forbids rvalue references.
+  if(!ExDeclType->isDependentType() && ExDeclType->isRValueReferenceType()) {
+    Diag(Loc, diag::err_catch_rvalue_ref) << Range;
+    Invalid = true;
+  }
+
+  QualType BaseType = ExDeclType;
+  int Mode = 0; // 0 for direct type, 1 for pointer, 2 for reference
+  unsigned DK = diag::err_catch_incomplete;
+  if (const PointerType *Ptr = BaseType->getAsPointerType()) {
+    BaseType = Ptr->getPointeeType();
+    Mode = 1;
+    DK = diag::err_catch_incomplete_ptr;
+  } else if(const ReferenceType *Ref = BaseType->getAsReferenceType()) {
+    // For the purpose of error recovery, we treat rvalue refs like lvalue refs.
+    BaseType = Ref->getPointeeType();
+    Mode = 2;
+    DK = diag::err_catch_incomplete_ref;
+  }
+  if (!Invalid && (Mode == 0 || !BaseType->isVoidType()) &&
+      !BaseType->isDependentType() && RequireCompleteType(Loc, BaseType, DK))
+    Invalid = true;
+
+  if (!Invalid && !ExDeclType->isDependentType() && 
+      RequireNonAbstractType(Loc, ExDeclType,
+                             diag::err_abstract_type_in_decl,
+                             AbstractVariableType))
+    Invalid = true;
+
+  // FIXME: Need to test for ability to copy-construct and destroy the
+  // exception variable.
+
+  // FIXME: Need to check for abstract classes.
+
+  VarDecl *ExDecl = VarDecl::Create(Context, CurContext, Loc, 
+                                    Name, ExDeclType, VarDecl::None, 
+                                    Range.getBegin());
+
+  if (Invalid)
+    ExDecl->setInvalidDecl();
+
+  return ExDecl;
+}
+
+/// ActOnExceptionDeclarator - Parsed the exception-declarator in a C++ catch
+/// handler.
+Sema::DeclPtrTy Sema::ActOnExceptionDeclarator(Scope *S, Declarator &D) {
+  QualType ExDeclType = GetTypeForDeclarator(D, S);
+
+  bool Invalid = D.isInvalidType();
+  IdentifierInfo *II = D.getIdentifier();
+  if (NamedDecl *PrevDecl = LookupName(S, II, LookupOrdinaryName)) {
+    // The scope should be freshly made just for us. There is just no way
+    // it contains any previous declaration.
+    assert(!S->isDeclScope(DeclPtrTy::make(PrevDecl)));
+    if (PrevDecl->isTemplateParameter()) {
+      // Maybe we will complain about the shadowed template parameter.
+      DiagnoseTemplateParameterShadow(D.getIdentifierLoc(), PrevDecl);
+    }
+  }
+
+  if (D.getCXXScopeSpec().isSet() && !Invalid) {
+    Diag(D.getIdentifierLoc(), diag::err_qualified_catch_declarator)
+      << D.getCXXScopeSpec().getRange();
+    Invalid = true;
+  }
+
+  VarDecl *ExDecl = BuildExceptionDeclaration(S, ExDeclType,
+                                              D.getIdentifier(),
+                                              D.getIdentifierLoc(),
+                                            D.getDeclSpec().getSourceRange());
+
+  if (Invalid)
+    ExDecl->setInvalidDecl();
+  
+  // Add the exception declaration into this scope.
+  if (II)
+    PushOnScopeChains(ExDecl, S);
+  else
+    CurContext->addDecl(Context, ExDecl);
+
+  ProcessDeclAttributes(ExDecl, D);
+  return DeclPtrTy::make(ExDecl);
+}
+
+Sema::DeclPtrTy Sema::ActOnStaticAssertDeclaration(SourceLocation AssertLoc, 
+                                                   ExprArg assertexpr,
+                                                   ExprArg assertmessageexpr) {
+  Expr *AssertExpr = (Expr *)assertexpr.get();
+  StringLiteral *AssertMessage = 
+    cast<StringLiteral>((Expr *)assertmessageexpr.get());
+
+  if (!AssertExpr->isTypeDependent() && !AssertExpr->isValueDependent()) {
+    llvm::APSInt Value(32);
+    if (!AssertExpr->isIntegerConstantExpr(Value, Context)) {
+      Diag(AssertLoc, diag::err_static_assert_expression_is_not_constant) <<
+        AssertExpr->getSourceRange();
+      return DeclPtrTy();
+    }
+
+    if (Value == 0) {
+      std::string str(AssertMessage->getStrData(), 
+                      AssertMessage->getByteLength());
+      Diag(AssertLoc, diag::err_static_assert_failed) 
+        << str << AssertExpr->getSourceRange();
+    }
+  }
+  
+  assertexpr.release();
+  assertmessageexpr.release();
+  Decl *Decl = StaticAssertDecl::Create(Context, CurContext, AssertLoc, 
+                                        AssertExpr, AssertMessage);
+  
+  CurContext->addDecl(Context, Decl);
+  return DeclPtrTy::make(Decl);
+}
+
+bool Sema::ActOnFriendDecl(Scope *S, SourceLocation FriendLoc, DeclPtrTy Dcl) {
+  if (!(S->getFlags() & Scope::ClassScope)) {
+    Diag(FriendLoc, diag::err_friend_decl_outside_class);
+    return true;
+  }
+  
+  return false;
+}
+
+void Sema::SetDeclDeleted(DeclPtrTy dcl, SourceLocation DelLoc) {
+  Decl *Dcl = dcl.getAs<Decl>();
+  FunctionDecl *Fn = dyn_cast<FunctionDecl>(Dcl);
+  if (!Fn) {
+    Diag(DelLoc, diag::err_deleted_non_function);
+    return;
+  }
+  if (const FunctionDecl *Prev = Fn->getPreviousDeclaration()) {
+    Diag(DelLoc, diag::err_deleted_decl_not_first);
+    Diag(Prev->getLocation(), diag::note_previous_declaration);
+    // If the declaration wasn't the first, we delete the function anyway for
+    // recovery.
+  }
+  Fn->setDeleted();
+}
+
+static void SearchForReturnInStmt(Sema &Self, Stmt *S) {
+  for (Stmt::child_iterator CI = S->child_begin(), E = S->child_end(); CI != E;
+       ++CI) {
+    Stmt *SubStmt = *CI;
+    if (!SubStmt)
+      continue;
+    if (isa<ReturnStmt>(SubStmt))
+      Self.Diag(SubStmt->getSourceRange().getBegin(),
+           diag::err_return_in_constructor_handler);
+    if (!isa<Expr>(SubStmt))
+      SearchForReturnInStmt(Self, SubStmt);
+  }
+}
+
+void Sema::DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock) {
+  for (unsigned I = 0, E = TryBlock->getNumHandlers(); I != E; ++I) {
+    CXXCatchStmt *Handler = TryBlock->getHandler(I);
+    SearchForReturnInStmt(*this, Handler);
+  }
+}
+
+bool Sema::CheckOverridingFunctionReturnType(const CXXMethodDecl *New, 
+                                             const CXXMethodDecl *Old) {
+  QualType NewTy = New->getType()->getAsFunctionType()->getResultType();
+  QualType OldTy = Old->getType()->getAsFunctionType()->getResultType();
+
+  QualType CNewTy = Context.getCanonicalType(NewTy);
+  QualType COldTy = Context.getCanonicalType(OldTy);
+
+  if (CNewTy == COldTy && 
+      CNewTy.getCVRQualifiers() == COldTy.getCVRQualifiers())
+    return false;
+  
+  // Check if the return types are covariant
+  QualType NewClassTy, OldClassTy;
+  
+  /// Both types must be pointers or references to classes.
+  if (PointerType *NewPT = dyn_cast<PointerType>(NewTy)) {
+    if (PointerType *OldPT = dyn_cast<PointerType>(OldTy)) {
+      NewClassTy = NewPT->getPointeeType();
+      OldClassTy = OldPT->getPointeeType();
+    }
+  } else if (ReferenceType *NewRT = dyn_cast<ReferenceType>(NewTy)) {
+    if (ReferenceType *OldRT = dyn_cast<ReferenceType>(OldTy)) {
+      NewClassTy = NewRT->getPointeeType();
+      OldClassTy = OldRT->getPointeeType();
+    }
+  }
+  
+  // The return types aren't either both pointers or references to a class type.
+  if (NewClassTy.isNull()) {
+    Diag(New->getLocation(), 
+         diag::err_different_return_type_for_overriding_virtual_function)
+      << New->getDeclName() << NewTy << OldTy;
+    Diag(Old->getLocation(), diag::note_overridden_virtual_function);
+    
+    return true;
+  }
+
+  if (NewClassTy.getUnqualifiedType() != OldClassTy.getUnqualifiedType()) {
+    // Check if the new class derives from the old class.
+    if (!IsDerivedFrom(NewClassTy, OldClassTy)) {
+      Diag(New->getLocation(),
+           diag::err_covariant_return_not_derived)
+      << New->getDeclName() << NewTy << OldTy;
+      Diag(Old->getLocation(), diag::note_overridden_virtual_function);
+      return true;
+    }
+    
+    // Check if we the conversion from derived to base is valid.
+    if (CheckDerivedToBaseConversion(NewClassTy, OldClassTy, 
+                      diag::err_covariant_return_inaccessible_base,
+                      diag::err_covariant_return_ambiguous_derived_to_base_conv,
+                      // FIXME: Should this point to the return type?
+                      New->getLocation(), SourceRange(), New->getDeclName())) {
+      Diag(Old->getLocation(), diag::note_overridden_virtual_function);
+      return true;
+    }
+  }
+  
+  // The qualifiers of the return types must be the same.
+  if (CNewTy.getCVRQualifiers() != COldTy.getCVRQualifiers()) {
+    Diag(New->getLocation(),
+         diag::err_covariant_return_type_different_qualifications)
+    << New->getDeclName() << NewTy << OldTy;
+    Diag(Old->getLocation(), diag::note_overridden_virtual_function);
+    return true;
+  };
+  
+
+  // The new class type must have the same or less qualifiers as the old type.
+  if (NewClassTy.isMoreQualifiedThan(OldClassTy)) {
+    Diag(New->getLocation(),
+         diag::err_covariant_return_type_class_type_more_qualified)
+    << New->getDeclName() << NewTy << OldTy;
+    Diag(Old->getLocation(), diag::note_overridden_virtual_function);
+    return true;
+  };
+  
+  return false;
+}