2 files changed, 14 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 4ec2dc6968b..1786b6372b0 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -3665,12 +3665,20 @@ void Sema::ActOnFields(Scope* S,
                        AttributeList *Attr) {
   Decl *EnclosingDecl = static_cast<Decl*>(RecDecl);
   assert(EnclosingDecl && "missing record or interface decl");
-  RecordDecl *Record = dyn_cast<RecordDecl>(EnclosingDecl);
+  
+  // If the decl this is being inserted into is invalid, then it may be a
+  // redeclaration or some other bogus case.  Don't try to add fields to it.
+  if (EnclosingDecl->isInvalidDecl()) {
+    // FIXME: Deallocate fields?
+    return;
+  }
+
   
   // Verify that all the fields are okay.
   unsigned NumNamedMembers = 0;
   llvm::SmallVector<FieldDecl*, 32> RecFields;
 
+  RecordDecl *Record = dyn_cast<RecordDecl>(EnclosingDecl);
   for (unsigned i = 0; i != NumFields; ++i) {
     FieldDecl *FD = cast_or_null<FieldDecl>(static_cast<Decl*>(Fields[i]));
     assert(FD && "missing field decl");
@@ -3782,9 +3790,8 @@ void Sema::ActOnFields(Scope* S,
           }
         }
       }
-    }
-    else if (ObjCImplementationDecl *IMPDecl = 
-               dyn_cast<ObjCImplementationDecl>(EnclosingDecl)) {
+    } else if (ObjCImplementationDecl *IMPDecl = 
+                  dyn_cast<ObjCImplementationDecl>(EnclosingDecl)) {
       assert(IMPDecl && "ActOnFields - missing ObjCImplementationDecl");
       IMPDecl->setIVarList(ClsFields, RecFields.size(), Context);
       CheckImplementationIvars(IMPDecl, ClsFields, RecFields.size(), RBrac);
diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index 660f745228b..b3644a5ab9c 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -78,6 +78,7 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
   if (IDecl) {
     // Class already seen. Is it a forward declaration?
     if (!IDecl->isForwardDecl()) {
+      IDecl->setInvalidDecl();
       Diag(AtInterfaceLoc, diag::err_duplicate_class_def)<<IDecl->getDeclName();
       Diag(IDecl->getLocation(), diag::note_previous_definition);
 
@@ -225,6 +226,7 @@ Sema::ActOnStartProtocolInterface(SourceLocation AtProtoInterfaceLoc,
   if (PDecl) {
     // Protocol already seen. Better be a forward protocol declaration
     if (!PDecl->isForwardDecl()) {
+      PDecl->setInvalidDecl();
       Diag(ProtocolLoc, diag::err_duplicate_protocol_def) << ProtocolName;
       Diag(PDecl->getLocation(), diag::note_previous_definition);
       // Just return the protocol we already had.
@@ -555,8 +557,7 @@ Sema::DeclTy *Sema::ActOnStartClassImplementation(
   if (PrevDecl && !isa<ObjCInterfaceDecl>(PrevDecl)) {
     Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
     Diag(PrevDecl->getLocation(), diag::note_previous_definition);
-  }
-  else {
+  }  else {
     // Is there an interface declaration of this class; if not, warn!
     IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl); 
     if (!IDecl)