diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 460e3de2282b..5623fe981ac7 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -900,7 +900,7 @@ protected:
 
 
 /// TagDecl - Represents the declaration of a struct/union/class/enum.
-class TagDecl : public TypeDecl {
+class TagDecl : public TypeDecl, public DeclContext {
 public:
   enum TagKind {
     TK_struct,
@@ -919,7 +919,7 @@ private:
 protected:
   TagDecl(Kind DK, TagKind TK, DeclContext *DC, SourceLocation L,
           IdentifierInfo *Id, ScopedDecl *PrevDecl)
-    : TypeDecl(DK, DC, L, Id, PrevDecl) {
+    : TypeDecl(DK, DC, L, Id, PrevDecl), DeclContext(DK) {
     assert((DK != Enum || TK == TK_enum) &&"EnumDecl not matched with TK_enum");
     TagDeclKind = TK;
     IsDefinition = false;
@@ -970,7 +970,7 @@ protected:
 
 /// EnumDecl - Represents an enum.  As an extension, we allow forward-declared
 /// enums.
-class EnumDecl : public TagDecl, public DeclContext {
+class EnumDecl : public TagDecl {
   /// IntegerType - This represent the integer type that the enum corresponds
   /// to for code generation purposes.  Note that the enumerator constants may
   /// have a different type than this does.
@@ -978,7 +978,7 @@ class EnumDecl : public TagDecl, public DeclContext {
   
   EnumDecl(DeclContext *DC, SourceLocation L,
            IdentifierInfo *Id, ScopedDecl *PrevDecl)
-    : TagDecl(Enum, TK_enum, DC, L, Id, PrevDecl), DeclContext(Enum) {
+    : TagDecl(Enum, TK_enum, DC, L, Id, PrevDecl) {
       IntegerType = QualType();
     }
 public:
@@ -1053,7 +1053,7 @@ protected:
 ///   union Y { int A, B; };     // Has body with members A and B (FieldDecls).
 /// This decl will be marked invalid if *any* members are invalid.
 ///
-class RecordDecl : public TagDecl, public DeclContext {
+class RecordDecl : public TagDecl {
   /// HasFlexibleArrayMember - This is true if this struct ends with a flexible
   /// array member (e.g. int X[]) or if this union contains a struct that does.
   /// If so, this cannot be contained in arrays or other structs as a member.
diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
index 6780a33c5b64..689ae69c63b3 100644
--- a/clang/include/clang/AST/DeclBase.h
+++ b/clang/include/clang/AST/DeclBase.h
@@ -68,9 +68,9 @@ public:
              Namespace,  // [DeclContext]
     //       TypeDecl
                Typedef,
-    //         TagDecl
-                 Enum,  // [DeclContext]
-                 Record, // [DeclContext]
+    //         TagDecl // [DeclContext]
+                 Enum,  
+                 Record,
                    CXXRecord,  
  	       TemplateTypeParm,
     //       ValueDecl
@@ -206,9 +206,6 @@ public:
     case OriginalParmVar:
     case EnumConstant:
     case NonTypeTemplateParm:
-    case Field:
-    case ObjCAtDefsField:
-    case ObjCIvar:
     case ObjCInterface:
     case ObjCCompatibleAlias:
     case OverloadedFunction:
@@ -216,6 +213,12 @@ public:
     case CXXConversion:
     case CXXClassVar:
       return IDNS_Ordinary;
+
+    case Field:
+    case ObjCAtDefsField:
+    case ObjCIvar:
+      return IDNS_Member;
+
     case Record:
     case CXXRecord:
     case TemplateTypeParm:
diff --git a/clang/include/clang/Parse/Action.h b/clang/include/clang/Parse/Action.h
index 5bba2a7b6df2..4c524f48d2df 100644
--- a/clang/include/clang/Parse/Action.h
+++ b/clang/include/clang/Parse/Action.h
@@ -341,10 +341,14 @@ public:
                            SourceLocation LBrac, SourceLocation RBrac,
                            AttributeList *AttrList) {}
   
-  /// ActOnEnumStartDefinition - Invoked when we have entered the
-  /// scope of the enumeration body and will be parsing its
-  /// enumerators.  
-  virtual void ActOnEnumStartDefinition(Scope *S, DeclTy *EnumDecl) { }
+  /// ActOnTagStartDefinition - Invoked when we have entered the
+  /// scope of a tag's definition (e.g., for an enumeration, class,
+  /// struct, or union).
+  virtual void ActOnTagStartDefinition(Scope *S, DeclTy *TagDecl) { }
+
+  /// ActOnTagFinishDefinition - Invoked once we have finished parsing
+  /// the definition of a tag (enumeration, class, struct, or union).
+  virtual void ActOnTagFinishDefinition(Scope *S, DeclTy *TagDecl) { }
 
   virtual DeclTy *ActOnEnumConstant(Scope *S, DeclTy *EnumDecl,
                                     DeclTy *LastEnumConstant,
@@ -915,12 +919,6 @@ public:
                                    unsigned NumBases) {
   }
                                    
-  /// ActOnStartCXXClassDef - This is called at the start of a class/struct/union
-  /// definition, when on C++.
-  virtual void ActOnStartCXXClassDef(Scope *S, DeclTy *TagDecl,
-                                     SourceLocation LBrace) {
-  }
-  
   /// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
   /// declarator is parsed. 'AS' is the access specifier, 'BitfieldWidth'
   /// specifies the bitfield width if there is one and 'Init' specifies the
@@ -962,11 +960,6 @@ public:
                                                  SourceLocation RBrac) {
   }
 
-  /// ActOnFinishCXXClassDef - This is called when a class/struct/union has
-  /// completed parsing, when on C++.
-  virtual void ActOnFinishCXXClassDef(DeclTy *TagDecl) {
-  }
-
   //===---------------------------C++ Templates----------------------------===//
 
   /// ActOnTypeParameter - Called when a C++ template type parameter
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index b3f19a25b860..8521b9b44ead 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -314,8 +314,7 @@ TagDecl* TagDecl::getDefinition(ASTContext& C) const {
 
 RecordDecl::RecordDecl(Kind DK, TagKind TK, DeclContext *DC, SourceLocation L,
                        IdentifierInfo *Id)
-  : TagDecl(DK, TK, DC, L, Id, 0), DeclContext(DK) {
-  
+  : TagDecl(DK, TK, DC, L, Id, 0) {
   HasFlexibleArrayMember = false;
   AnonymousStructOrUnion = false;
   assert(classof(static_cast<Decl*>(this)) && "Invalid Kind!");
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 49890144a956..83f8fa411f93 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -579,6 +579,7 @@ DeclContext::lookup(DeclarationName Name) const {
 
 const DeclContext *DeclContext::getLookupContext() const {
   const DeclContext *Ctx = this;
+  // Skip through transparent contexts.
   while (Ctx->isTransparentContext())
     Ctx = Ctx->getParent();
   return Ctx;
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index c4126f3bb46d..219295fa74d8 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -948,6 +948,9 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
                                   unsigned TagType, DeclTy *TagDecl) {
   SourceLocation LBraceLoc = ConsumeBrace();
   
+  ParseScope StructScope(this, Scope::DeclScope);
+  Actions.ActOnTagStartDefinition(CurScope, TagDecl);
+
   // Empty structs are an extension in C (C99 6.7.2.1p7), but are allowed in
   // C++.
   if (Tok.is(tok::r_brace) && !getLang().CPlusPlus)
@@ -1027,7 +1030,9 @@ void Parser::ParseStructUnionBody(SourceLocation RecordLoc,
   Actions.ActOnFields(CurScope,
                       RecordLoc,TagDecl,&FieldDecls[0],FieldDecls.size(),
                       LBraceLoc, RBraceLoc,
-                      AttrList);  
+                      AttrList);
+  StructScope.Exit();
+  Actions.ActOnTagFinishDefinition(CurScope, TagDecl);
 }
 
 
@@ -1125,7 +1130,7 @@ void Parser::ParseEnumSpecifier(DeclSpec &DS) {
 void Parser::ParseEnumBody(SourceLocation StartLoc, DeclTy *EnumDecl) {
   // Enter the scope of the enum body and start the definition.
   ParseScope EnumScope(this, Scope::DeclScope);
-  Actions.ActOnEnumStartDefinition(CurScope, EnumDecl);
+  Actions.ActOnTagStartDefinition(CurScope, EnumDecl);
 
   SourceLocation LBraceLoc = ConsumeBrace();
   
@@ -1178,6 +1183,9 @@ void Parser::ParseEnumBody(SourceLocation StartLoc, DeclTy *EnumDecl) {
   // If attributes exist after the identifier list, parse them.
   if (Tok.is(tok::kw___attribute))
     AttrList = ParseAttributes(); // FIXME: where do they do?
+
+  EnumScope.Exit();
+  Actions.ActOnTagFinishDefinition(CurScope, EnumDecl);
 }
 
 /// isTypeSpecifierQualifier - Return true if the current token could be the
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 81ea52ca690e..c6c2ae4cfe18 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -730,7 +730,7 @@ void Parser::ParseCXXMemberSpecification(SourceLocation RecordLoc,
   // Enter a scope for the class.
   ParseScope ClassScope(this, Scope::CXXClassScope|Scope::DeclScope);
 
-  Actions.ActOnStartCXXClassDef(CurScope, TagDecl, LBraceLoc);
+  Actions.ActOnTagStartDefinition(CurScope, TagDecl);
 
   // C++ 11p3: Members of a class defined with the keyword class are private
   // by default. Members of a class defined with the keywords struct or union
@@ -802,7 +802,7 @@ void Parser::ParseCXXMemberSpecification(SourceLocation RecordLoc,
   // Leave the class scope.
   ClassScope.Exit();
 
-  Actions.ActOnFinishCXXClassDef(TagDecl);
+  Actions.ActOnTagFinishDefinition(CurScope, TagDecl);
 }
 
 /// ParseConstructorInitializer - Parse a C++ constructor initializer,
diff --git a/clang/lib/Parse/ParseObjc.cpp b/clang/lib/Parse/ParseObjc.cpp
index 759de7a0648d..cc13a5e0ae18 100644
--- a/clang/lib/Parse/ParseObjc.cpp
+++ b/clang/lib/Parse/ParseObjc.cpp
@@ -840,6 +840,8 @@ void Parser::ParseObjCClassInstanceVariables(DeclTy *interfaceDecl,
   llvm::SmallVector<DeclTy*, 32> AllIvarDecls;
   llvm::SmallVector<FieldDeclarator, 8> FieldDeclarators;
 
+  ParseScope ClassScope(this, Scope::DeclScope);
+
   SourceLocation LBraceLoc = ConsumeBrace(); // the "{"
   
   tok::ObjCKeywordKind visibility = tok::objc_protected;
diff --git a/clang/lib/Sema/IdentifierResolver.cpp b/clang/lib/Sema/IdentifierResolver.cpp
index 90906e72746e..762885e42c38 100644
--- a/clang/lib/Sema/IdentifierResolver.cpp
+++ b/clang/lib/Sema/IdentifierResolver.cpp
@@ -60,6 +60,9 @@ DeclContext *IdentifierResolver::LookupContext::getContext(Decl *D) {
   else
     return TUCtx();
 
+  if (!Ctx) // FIXME: HACK! We shouldn't end up with a NULL context here.
+    return TUCtx();
+
   Ctx = Ctx->getLookupContext();
 
   if (isa<TranslationUnitDecl>(Ctx))
diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 765dfe5420ca..61be6445d129 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -327,7 +327,16 @@ public:
                            DeclTy **Fields, unsigned NumFields,
                            SourceLocation LBrac, SourceLocation RBrac,
                            AttributeList *AttrList);
-  virtual void ActOnEnumStartDefinition(Scope *S, DeclTy *EnumDecl);
+
+  /// ActOnTagStartDefinition - Invoked when we have entered the
+  /// scope of a tag's definition (e.g., for an enumeration, class,
+  /// struct, or union).
+  virtual void ActOnTagStartDefinition(Scope *S, DeclTy *TagDecl);
+
+  /// ActOnTagFinishDefinition - Invoked once we have finished parsing
+  /// the definition of a tag (enumeration, class, struct, or union).
+  virtual void ActOnTagFinishDefinition(Scope *S, DeclTy *TagDecl);
+
   virtual DeclTy *ActOnEnumConstant(Scope *S, DeclTy *EnumDecl,
                                     DeclTy *LastEnumConstant,
                                     SourceLocation IdLoc, IdentifierInfo *Id,
@@ -1017,9 +1026,6 @@ public:
   virtual bool isCurrentClassName(const IdentifierInfo &II, Scope *S,
                                   const CXXScopeSpec *SS);
   
-  virtual void ActOnStartCXXClassDef(Scope *S, DeclTy *TagDecl,
-                                     SourceLocation LBrace);
-
   virtual DeclTy *ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS,
                                            Declarator &D, ExprTy *BitfieldWidth,
                                            ExprTy *Init, DeclTy *LastInGroup);
@@ -1040,8 +1046,6 @@ public:
                                                  SourceLocation LBrac,
                                                  SourceLocation RBrac);
 
-  virtual void ActOnFinishCXXClassDef(DeclTy *TagDecl);
-  
   virtual void ActOnStartDelayedCXXMethodDeclaration(Scope *S, DeclTy *Method);
   virtual void ActOnDelayedCXXMethodParameter(Scope *S, DeclTy *Param);
   virtual void ActOnFinishDelayedCXXMethodDeclaration(Scope *S, DeclTy *Method);
diff --git a/clang/lib/Sema/SemaCXXScopeSpec.cpp b/clang/lib/Sema/SemaCXXScopeSpec.cpp
index 5fb2740fcf31..dcb2a5fba551 100644
--- a/clang/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/clang/lib/Sema/SemaCXXScopeSpec.cpp
@@ -28,7 +28,7 @@ namespace {
       DeclContext::lookup_const_iterator I, E;
       for (llvm::tie(I, E) = LookupCtx->lookup(Name); I != E; ++I) {
        IdIsUndeclared = false;
-       if (((*I)->getIdentifierNamespace() & Decl::IDNS_Tag) || 
+       if (((*I)->isInIdentifierNamespace(Decl::IDNS_Tag)) || 
            isa<TypedefDecl>(*I))
          return *I;
       }
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 6585733ab38b..c6e4336a3dc8 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -263,18 +263,37 @@ Decl *Sema::LookupDecl(DeclarationName Name, unsigned NSI, Scope *S,
                        bool NamespaceNameOnly) {
   if (!Name) return 0;
   unsigned NS = NSI;
-  if (getLangOptions().CPlusPlus && (NS & Decl::IDNS_Ordinary))
-    NS |= Decl::IDNS_Tag;
 
-  if (LookupCtx == 0 && 
-      (!getLangOptions().CPlusPlus || (NS == Decl::IDNS_Label))) {
-    // Unqualified name lookup in C/Objective-C and name lookup for
-    // labels in C++ is purely lexical, so search in the
-    // declarations attached to the name.
+  // In C++, ordinary and member lookup will always find all
+  // kinds of names.
+  if (getLangOptions().CPlusPlus && 
+      (NS & (Decl::IDNS_Ordinary | Decl::IDNS_Member)))
+    NS |= Decl::IDNS_Tag | Decl::IDNS_Member | Decl::IDNS_Ordinary;
+
+  if (LookupCtx == 0 && !getLangOptions().CPlusPlus) {
+    // Unqualified name lookup in C/Objective-C is purely lexical, so
+    // search in the declarations attached to the name.
     assert(!LookupCtx && "Can't perform qualified name lookup here");
     assert(!NamespaceNameOnly && "Can't perform namespace name lookup here");
+
+    // For the purposes of unqualified name lookup, structs and unions
+    // don't have scopes at all. For example:
+    //
+    //   struct X {
+    //     struct T { int i; } x;
+    //   };
+    //
+    //   void f() {
+    //     struct T t; // okay: T is defined lexically within X, but
+    //                 // semantically at global scope
+    //   };
+    //
+    // FIXME: Is there a better way to deal with this?
+    DeclContext *SearchCtx = CurContext;
+    while (isa<RecordDecl>(SearchCtx) || isa<EnumDecl>(SearchCtx))
+      SearchCtx = SearchCtx->getParent();
     IdentifierResolver::iterator I
-      = IdResolver.begin(Name, CurContext, LookInParent);
+      = IdResolver.begin(Name, SearchCtx, LookInParent);
     
     // Scan up the scope chain looking for a decl that matches this
     // identifier that is in the appropriate namespace.  This search
@@ -284,6 +303,11 @@ Decl *Sema::LookupDecl(DeclarationName Name, unsigned NSI, Scope *S,
       if ((*I)->isInIdentifierNamespace(NS))
         return *I;
   } else if (LookupCtx) {
+    // If we're performing qualified name lookup (e.g., lookup into a
+    // struct), find fields as part of ordinary name lookup.
+    if (NS & Decl::IDNS_Ordinary)
+      NS |= Decl::IDNS_Member;
+
     // Perform qualified name lookup into the LookupCtx.
     // FIXME: Will need to look into base classes and such.
     DeclContext::lookup_const_iterator I, E;
@@ -2852,6 +2876,15 @@ Sema::DeclTy *Sema::ActOnTag(Scope *S, unsigned TagType, TagKind TK,
     // declaration or definition.
     // Use ScopedDecl instead of TagDecl, because a NamespaceDecl may come up.
     PrevDecl = dyn_cast_or_null<ScopedDecl>(LookupDecl(Name, Decl::IDNS_Tag,S));
+
+    if (!getLangOptions().CPlusPlus && TK != TK_Reference) {
+      // FIXME: This makes sure that we ignore the contexts associated
+      // with C structs, unions, and enums when looking for a matching
+      // tag declaration or definition. See the similar lookup tweak
+      // in Sema::LookupDecl; is there a better way to deal with this?
+      while (isa<RecordDecl>(DC) || isa<EnumDecl>(DC))
+        DC = DC->getParent();
+    }
   }
 
   if (PrevDecl && PrevDecl->isTemplateParameter()) {
@@ -3007,6 +3040,43 @@ CreateNewDecl:
   return New;
 }
 
+void Sema::ActOnTagStartDefinition(Scope *S, DeclTy *TagD) {
+  TagDecl *Tag = cast<TagDecl>((Decl *)TagD);
+
+  // Enter the tag context.
+  PushDeclContext(S, Tag);
+
+  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Tag)) {
+    FieldCollector->StartClass();
+
+    if (Record->getIdentifier()) {
+      // C++ [class]p2: 
+      //   [...] The class-name is also inserted into the scope of the
+      //   class itself; this is known as the injected-class-name. For
+      //   purposes of access checking, the injected-class-name is treated
+      //   as if it were a public member name.
+      RecordDecl *InjectedClassName
+        = CXXRecordDecl::Create(Context, Record->getTagKind(),
+                                CurContext, Record->getLocation(),
+                                Record->getIdentifier(), Record);
+      InjectedClassName->setImplicit();
+      PushOnScopeChains(InjectedClassName, S);
+    }
+  }
+}
+
+void Sema::ActOnTagFinishDefinition(Scope *S, DeclTy *TagD) {
+  TagDecl *Tag = cast<TagDecl>((Decl *)TagD);
+
+  if (isa<CXXRecordDecl>(Tag))
+    FieldCollector->FinishClass();
+
+  // Exit this scope of this tag's definition.
+  PopDeclContext();
+
+  // Notify the consumer that we've defined a tag.
+  Consumer.HandleTagDeclDefinition(Tag);
+}
 
 /// TryToFixInvalidVariablyModifiedType - Helper method to turn variable array
 /// types into constant array types in certain situations which would otherwise
@@ -3108,6 +3178,18 @@ Sema::DeclTy *Sema::ActOnField(Scope *S, DeclTy *TagD,
                               DeclSpec::SCS_mutable,
                             /*PrevDecl=*/0);
 
+  if (II) {
+    Decl *PrevDecl 
+      = LookupDecl(II, Decl::IDNS_Member, S, 0, false, false, false);
+    if (PrevDecl && isDeclInScope(PrevDecl, CurContext, S)
+        && !isa<TagDecl>(PrevDecl)) {
+      Diag(Loc, diag::err_duplicate_member) << II;
+      Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
+      NewFD->setInvalidDecl();
+      Record->setInvalidDecl();
+    }
+  }
+
   if (getLangOptions().CPlusPlus) {
     CheckExtraCXXDefaultArguments(D);
     if (!T->isPODType())
@@ -3119,9 +3201,9 @@ Sema::DeclTy *Sema::ActOnField(Scope *S, DeclTy *TagD,
   if (D.getInvalidType() || InvalidDecl)
     NewFD->setInvalidDecl();
 
-  if (II && getLangOptions().CPlusPlus)
+  if (II) {
     PushOnScopeChains(NewFD, S);
-  else
+  } else
     Record->addDecl(Context, NewFD);
 
   return NewFD;
@@ -3146,6 +3228,7 @@ Sema::DeclTy *Sema::ActOnIvar(Scope *S,
                               SourceLocation DeclStart, 
                               Declarator &D, ExprTy *BitfieldWidth,
                               tok::ObjCKeywordKind Visibility) {
+  
   IdentifierInfo *II = D.getIdentifier();
   Expr *BitWidth = (Expr*)BitfieldWidth;
   SourceLocation Loc = DeclStart;
@@ -3188,12 +3271,30 @@ Sema::DeclTy *Sema::ActOnIvar(Scope *S,
   ObjCIvarDecl *NewID = ObjCIvarDecl::Create(Context, Loc, II, T, ac,                                             
                                              (Expr *)BitfieldWidth);
   
+  if (II) {
+    Decl *PrevDecl 
+      = LookupDecl(II, Decl::IDNS_Member, S, 0, false, false, false);
+    if (PrevDecl && isDeclInScope(PrevDecl, CurContext, S)
+        && !isa<TagDecl>(PrevDecl)) {
+      Diag(Loc, diag::err_duplicate_member) << II;
+      Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
+      NewID->setInvalidDecl();
+    }
+  }
+
   // Process attributes attached to the ivar.
   ProcessDeclAttributes(NewID, D);
   
   if (D.getInvalidType() || InvalidDecl)
     NewID->setInvalidDecl();
 
+  if (II) {
+    // FIXME: When interfaces are DeclContexts, we'll need to add
+    // these to the interface.
+    S->AddDecl(NewID);
+    IdResolver.AddDecl(NewID);
+  }
+
   return NewID;
 }
 
@@ -3206,27 +3307,26 @@ void Sema::ActOnFields(Scope* S,
   assert(EnclosingDecl && "missing record or interface decl");
   RecordDecl *Record = dyn_cast<RecordDecl>(EnclosingDecl);
   
-  if (Record)
-    if (RecordDecl* DefRecord = Record->getDefinition(Context)) {
+  if (Record) {
+    QualType RecordType = Context.getTypeDeclType(Record);
+    if (RecordType->getAsRecordType()->getDecl()->isDefinition()) {
+      RecordDecl *Def = RecordType->getAsRecordType()->getDecl();
       // Diagnose code like:
       //     struct S { struct S {} X; };
       // We discover this when we complete the outer S.  Reject and ignore the
       // outer S.
-      Diag(DefRecord->getLocation(), diag::err_nested_redefinition)
-        << DefRecord->getDeclName();
+      Diag(Def->getLocation(), diag::err_nested_redefinition)
+        << Def->getDeclName();
       Diag(RecLoc, diag::note_previous_definition);
       Record->setInvalidDecl();
       return;
     }
+  }
   
   // Verify that all the fields are okay.
   unsigned NumNamedMembers = 0;
   llvm::SmallVector<FieldDecl*, 32> RecFields;
 
-  // FIXME: Eventually, we'd like to eliminate this in favor of
-  // checking for redeclarations on-the-fly.
-  llvm::DenseMap<const IdentifierInfo*, FieldDecl *> FieldIDs;
-  
   for (unsigned i = 0; i != NumFields; ++i) {
     FieldDecl *FD = cast_or_null<FieldDecl>(static_cast<Decl*>(Fields[i]));
     assert(FD && "missing field decl");
@@ -3234,37 +3334,7 @@ void Sema::ActOnFields(Scope* S,
     // Get the type for the field.
     Type *FDTy = FD->getType().getTypePtr();
 
-    if (FD->isAnonymousStructOrUnion()) {
-      // We have found a field that represents an anonymous struct
-      // or union. Introduce all of the inner fields (recursively)
-      // into the list of fields we know about, so that we can produce
-      // an appropriate error message in cases like:
-      //
-      //   struct X {
-      //     union {
-      //       int x;
-      //       float f;
-      //     };
-      //     double x;
-      //   };
-      llvm::SmallVector<FieldDecl *, 4> AnonStructUnionFields;
-      AnonStructUnionFields.push_back(FD);
-      while (!AnonStructUnionFields.empty()) {
-        FieldDecl *AnonField = AnonStructUnionFields.back();
-        AnonStructUnionFields.pop_back();
-        
-        RecordDecl *AnonRecord 
-          = AnonField->getType()->getAsRecordType()->getDecl();
-        for (RecordDecl::field_iterator F = AnonRecord->field_begin(),
-                                     FEnd = AnonRecord->field_end();
-             F != FEnd; ++F) {
-          if ((*F)->isAnonymousStructOrUnion())
-            AnonStructUnionFields.push_back(*F);
-          else if (const IdentifierInfo *II = (*F)->getIdentifier())
-            FieldIDs[II] = *F;
-        }
-      }
-    } else {
+    if (!FD->isAnonymousStructOrUnion()) {
       // Remember all fields written by the user.
       RecFields.push_back(FD);
     }
@@ -3340,28 +3410,13 @@ void Sema::ActOnFields(Scope* S,
       continue;
     }
     // Keep track of the number of named members.
-    if (IdentifierInfo *II = FD->getIdentifier()) {
-      // Detect duplicate member names.
-      if (FieldIDs[II]) {
-        Diag(FD->getLocation(), diag::err_duplicate_member) << II;
-        // Find the previous decl.
-        Diag(FieldIDs[II]->getLocation(), diag::note_previous_definition);
-        FD->setInvalidDecl();
-        EnclosingDecl->setInvalidDecl();
-        continue;
-      }
+    if (FD->getIdentifier())
       ++NumNamedMembers;
-      FieldIDs[II] = FD;
-    }
   }
 
   // Okay, we successfully defined 'Record'.
   if (Record) {
     Record->completeDefinition(Context);
-    // If this is a C++ record, HandleTagDeclDefinition will be invoked in
-    // Sema::ActOnFinishCXXClassDef.
-    if (!isa<CXXRecordDecl>(Record))
-      Consumer.HandleTagDeclDefinition(Record);
   } else {
     ObjCIvarDecl **ClsFields = reinterpret_cast<ObjCIvarDecl**>(&RecFields[0]);
     if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(EnclosingDecl)) {
@@ -3376,7 +3431,7 @@ void Sema::ActOnFields(Scope* S,
           ObjCIvarDecl* prevIvar = ID->getSuperClass()->FindIvarDeclaration(II);
           if (prevIvar) {
             Diag(Ivar->getLocation(), diag::err_duplicate_member) << II;
-            Diag(prevIvar->getLocation(), diag::note_previous_definition);
+            Diag(prevIvar->getLocation(), diag::note_previous_declaration);
           }
         }
       }
@@ -3393,13 +3448,6 @@ void Sema::ActOnFields(Scope* S,
     ProcessDeclAttributeList(Record, Attr);
 }
 
-void Sema::ActOnEnumStartDefinition(Scope *S, DeclTy *EnumD) {
-  EnumDecl *Enum = cast<EnumDecl>((Decl *)EnumD);
-
-  // Enter the enumeration context.
-  PushDeclContext(S, Enum);
-}
-
 Sema::DeclTy *Sema::ActOnEnumConstant(Scope *S, DeclTy *theEnumDecl,
                                       DeclTy *lastEnumConst,
                                       SourceLocation IdLoc, IdentifierInfo *Id,
@@ -3507,7 +3555,6 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, DeclTy *EnumDeclX,
       << Enum->getDeclName();
     Diag(Enum->getLocation(), diag::note_previous_definition);
     Enum->setInvalidDecl();
-    PopDeclContext();
     return;
   }
 
@@ -3675,10 +3722,6 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, DeclTy *EnumDeclX,
   }
   
   Enum->completeDefinition(Context, BestType);
-  Consumer.HandleTagDeclDefinition(Enum);
-
-  // Leave the context of the enumeration.
-  PopDeclContext();
 }
 
 Sema::DeclTy *Sema::ActOnFileScopeAsmDecl(SourceLocation Loc,
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index edc3a28dcf5d..dea3688bdbfb 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -414,28 +414,6 @@ void Sema::ActOnBaseSpecifiers(DeclTy *ClassDecl, BaseTy **Bases,
 // C++ class member Handling
 //===----------------------------------------------------------------------===//
 
-/// ActOnStartCXXClassDef - This is called at the start of a class/struct/union
-/// definition, when on C++.
-void Sema::ActOnStartCXXClassDef(Scope *S, DeclTy *D, SourceLocation LBrace) {
-  CXXRecordDecl *Dcl = cast<CXXRecordDecl>(static_cast<Decl *>(D));
-  PushDeclContext(S, Dcl);
-  FieldCollector->StartClass();
-
-  if (Dcl->getIdentifier()) {
-    // C++ [class]p2: 
-    //   [...] The class-name is also inserted into the scope of the
-    //   class itself; this is known as the injected-class-name. For
-    //   purposes of access checking, the injected-class-name is treated
-    //   as if it were a public member name.
-    RecordDecl *InjectedClassName
-      = CXXRecordDecl::Create(Context, Dcl->getTagKind(),
-                              CurContext, Dcl->getLocation(),
-                              Dcl->getIdentifier(), Dcl);
-    InjectedClassName->setImplicit();
-    PushOnScopeChains(InjectedClassName, S);
-  }
-}
-
 /// 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
@@ -975,16 +953,6 @@ void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
   }
 }
 
-void Sema::ActOnFinishCXXClassDef(DeclTy *D) {
-  CXXRecordDecl *Rec = cast<CXXRecordDecl>(static_cast<Decl *>(D));
-  FieldCollector->FinishClass();
-  PopDeclContext();
-
-  // Everything, including inline method definitions, have been parsed.
-  // Let the consumer know of the new TagDecl definition.
-  Consumer.HandleTagDeclDefinition(Rec);
-}
-
 /// 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
diff --git a/clang/test/Sema/member-reference.c b/clang/test/Sema/member-reference.c
index 784d60020ad3..b434f5b77938 100644
--- a/clang/test/Sema/member-reference.c
+++ b/clang/test/Sema/member-reference.c
@@ -7,3 +7,14 @@ void f(void) {
    s->i = 1;
 }
 
+typedef int x;
+struct S {
+  int x;
+  x z;
+};
+
+void g(void) {
+  struct S s[1];
+  s->x = 1;
+  s->z = 2;
+}
diff --git a/clang/test/Sema/nested-redef.c b/clang/test/Sema/nested-redef.c
new file mode 100644
index 000000000000..83cd4209675c
--- /dev/null
+++ b/clang/test/Sema/nested-redef.c
@@ -0,0 +1,22 @@
+// RUN: clang -fsyntax-only -verify %s
+struct X { // expected-note{{previous definition is here}}
+  struct X { } x; // expected-error{{nested redefinition of 'X'}}
+}; 
+
+struct Y { };
+void f(void) {
+  struct Y { }; // okay: this is a different Y
+}
+
+struct T;
+struct Z {
+  struct T { int x; } t;
+  struct U { int x; } u;
+};
+
+void f2(void) {
+  struct T t;
+  // FIXME: this is well-formed, but Clang breaks on it struct U u;
+}
+
+
diff --git a/clang/test/SemaCXX/anonymous-union.cpp b/clang/test/SemaCXX/anonymous-union.cpp
index a66745b37848..872c45c46897 100644
--- a/clang/test/SemaCXX/anonymous-union.cpp
+++ b/clang/test/SemaCXX/anonymous-union.cpp
@@ -66,7 +66,7 @@ struct Redecl {
   union {
     int x; // expected-error{{member of anonymous union redeclares 'x'}}
     float y;
-    double z; // expected-note{{previous definition is here}}
+    double z; // expected-note{{previous declaration is here}}
     double zz; // expected-note{{previous definition is here}}
   };
 
diff --git a/clang/test/SemaCXX/class.cpp b/clang/test/SemaCXX/class.cpp
index 7e06415a09da..d739af87dd79 100644
--- a/clang/test/SemaCXX/class.cpp
+++ b/clang/test/SemaCXX/class.cpp
@@ -53,7 +53,7 @@ public:
 
   typedef int A;
 
-  virtual int vi; // expected-error {{error: 'virtual' can only appear on non-static member functions}}
+  virtual int viv; // expected-error {{error: 'virtual' can only appear on non-static member functions}}
   virtual static int vsif(); // expected-error {{error: 'virtual' can only appear on non-static member functions}}
   virtual int vif();
 
@@ -105,3 +105,8 @@ void ogfn()
   struct C4;
   C4; // expected-error {{declaration does not declare anything}}
 }
+
+struct C4 {
+  void f(); // expected-note{{previous declaration is here}}
+  int f; // expected-error{{duplicate member 'f'}}
+};
diff --git a/clang/test/SemaObjC/duplicate-ivar-check.m b/clang/test/SemaObjC/duplicate-ivar-check.m
index ea42e9e277b7..6dcdc38dc300 100644
--- a/clang/test/SemaObjC/duplicate-ivar-check.m
+++ b/clang/test/SemaObjC/duplicate-ivar-check.m
@@ -2,13 +2,13 @@
 
 @interface B1 {
 @public
-  double fill_B;	// expected-note {{previous definition is here}}
+  double fill_B;	// expected-note {{previous declaration is here}}
 }
 @end
 
 @interface B : B1 {
 @public
-  int one;	// expected-note {{previous definition is here}}
+  int one;	// expected-note {{previous declaration is here}}
   int one;	// expected-error {{duplicate member 'one'}}
 }
 @end
diff --git a/clang/test/SemaObjC/interface-scope.m b/clang/test/SemaObjC/interface-scope.m
new file mode 100644
index 000000000000..8f164a9f7360
--- /dev/null
+++ b/clang/test/SemaObjC/interface-scope.m
@@ -0,0 +1,12 @@
+// RUN: clang -fsyntax-only -verify %s
+
+@interface I1 {
+@private
+  int x;
+  struct {
+    unsigned int x : 3;
+    unsigned int y : 3;
+  } flags;
+  int y;
+}
+@end
diff --git a/clang/test/SemaObjC/ivar-sem-check-1.m b/clang/test/SemaObjC/ivar-sem-check-1.m
index 3416b31112ac..a6d1a22a9157 100644
--- a/clang/test/SemaObjC/ivar-sem-check-1.m
+++ b/clang/test/SemaObjC/ivar-sem-check-1.m
@@ -12,7 +12,7 @@ typedef int FOO();
 	  struct T {} X;  // expected-error {{nested redefinition of 'T'}}
 	}YYY; 
 	FOO    BADFUNC;  // expected-error {{field 'BADFUNC' declared as a function}}
-	int kaka;	// expected-note {{previous definition is here}}
+	int kaka;	// expected-note {{previous declaration is here}}
 	int kaka;	// expected-error {{duplicate member 'kaka'}}
 	char ch[];	// expected-error {{field 'ch' has incomplete type}}
 }