Testcase:

template<class T>
class a {}
  class temp {};
a<temp> b;
struct b {
}

gcc-4.6:

clang-2.C:3:15: error: multiple types in one declaration
clang-2.C:4:7: error: non-template type ‘a’ used as a template
clang-2.C:4:10: error: invalid type in declaration before ‘;’ token
clang-2.C:6:1: error: expected unqualified-id at end of input

clang:

 t.cc:2:11: error: expected ';' after class
  class a {}
            ^
            ;
  t.cc:6:2: error: expected ';' after struct
  }
   ^
   ;