http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-16 23:09:30 UTC ---
template<typename T>
struct X { };
template<typename T>
using Y = const X<T>;
template<typename T>
using Z = Y<T>;