http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58977
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- I think this is http://www.open-std.org/Jtc1/sc22/wg21/docs/cwg_defects.html#1288 which makes this a duplicate of PR 50025
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58977
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- I think this is http://www.open-std.org/Jtc1/sc22/wg21/docs/cwg_defects.html#1288 which makes this a duplicate of PR 50025