[Parser] Fix assertion-on-invalid for unexpected typename.

In `ParseDeclarationSpecifiers` for the code

    class A typename A;

we were able to annotate token `kw_typename` because it refers to
existing type. But later during processing token `annot_typename` we
failed to `SetTypeSpecType` and exited switch statement leaving
annotation token unconsumed. The code after the switch statement failed
because it didn't expect a special token.

The fix is not to assume that switch statement consumes all special
tokens and consume any token, not just non-special.

rdar://problem/37099386

Reviewers: rsmith, arphaman

Reviewed By: rsmith

Subscribers: jkorous-apple, cfe-commits

Differential Revision: https://reviews.llvm.org/D44449

llvm-svn: 329735
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 8ce4c9a..f17212d 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3804,7 +3804,8 @@
 
     DS.SetRangeEnd(Tok.getLocation());
     if (DiagID != diag::err_bool_redeclaration)
-      ConsumeToken();
+      // After an error the next token can be an annotation token.
+      ConsumeAnyToken();
 
     AttrsLastTime = false;
   }