http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56936
--- Comment #4 from Ivan Sorokin <vanyacpp at gmail dot com> 2013-04-13 11:06:35 UTC --- (In reply to comment #3) > [temp.res]/8 "If no valid specialization can be generated for a template, and > that template is not instantiated, the template is ill-formed, no diagnostic > required." > > No diagnostic required. Yes, but diagnostic would be very helpful. Moreover clang prints error on this code.