http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52363
--- Comment #9 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-04-18 14:59:02 UTC --- Ah, thanks Daniel. Therefore the situation is becoming more clear. Then - assuming this interpretation is correct - I'm not sure what we want to do from a practical point of view: should we arrange the front-end to always have the static_assertion triggered (thus, even without -pedantic) or we really want that only when -pedantic is passed? I'm not clear whether the user may like to see the value is std::is_assignable changing depending on -pedantic?!? I never pondered that possibility in the past. I guess Jason should give a direction, here.