http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51452
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-12-07 17:16:58 UTC --- I think this is by design, see the thread beginning with c++std-lib-30698 I've been surprised by that reasoning several times e.g. http://gcc.gnu.org/ml/gcc-help/2011-11/msg00015.html
