https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67017
--- Comment #6 from Anders Granlund <anders.granlund.0 at gmail dot com> --- Now I got the reply. It seems like the wording of the standard changed with the resolution of this c++ standard core defect: http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1265 So the problem is that GCC hasn't implemented this yet.
