http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50711
--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-13 02:19:27 UTC --- Eg, if you simply open the <functional> header you will find plenty of decltype( std::declval... for sfinae, which cannot be replaced by a concise std::result_of
