Patch to fix a crash on incomplete class declaration.

Radar 7923673.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@103812 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaDecl.cpp

@@ -5329,9 +5329,13 @@ CreateNewDecl:
 
   // Maybe add qualifier info.
   if (SS.isNotEmpty()) {
-    NestedNameSpecifier *NNS
-      = static_cast<NestedNameSpecifier*>(SS.getScopeRep());
-    New->setQualifierInfo(NNS, SS.getRange());
+    if (SS.isSet()) {
+      NestedNameSpecifier *NNS
+        = static_cast<NestedNameSpecifier*>(SS.getScopeRep());
+      New->setQualifierInfo(NNS, SS.getRange());
+    }
+    else
+      Invalid = true;
   }
 
   if (Kind != TTK_Enum) {

test/Parser/cxx-undeclared-identifier.cpp

@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -fsyntax-only -pedantic -verify %s
+
+class Foo::Bar { // expected-error {{use of undeclared identifier 'Foo'}} \
+                 // expected-note {{to match this '{'}} \
+                 // expected-error {{expected ';' after class}}
+                 // expected-error {{expected '}'}}