http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58590
--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Or, I don't know, simple C++98 which we should also reject:
//------------------
struct S { int member; struct member{}; };
template<class T, class = typename T::member>
struct C { };
template class C<S>;
//------------------
