Follow-up to r217302: Don't crash on ~A::A() if A is undeclared.

llvm-svn: 227555
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index 422b486..a753b0f 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -2516,7 +2516,8 @@
       }
       if (ParseOptionalCXXScopeSpecifier(SS, ObjectType, EnteringContext))
         return true;
-      if (Tok.isNot(tok::identifier) || NextToken().is(tok::coloncolon)) {
+      if (Tok.isNot(tok::identifier) || NextToken().is(tok::coloncolon) ||
+          SS.isInvalid()) {
         Diag(TildeLoc, diag::err_destructor_tilde_scope);
         return true;
       }