http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55043
--- Comment #26 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-01-16 10:25:57 UTC --- (In reply to comment #24) > That really feels like a hack. It is a hack, to work around a throwing move ctor that I don't have time to fix. > Anyone using boost::is_copy_constructible or > whatever personal trick to detect copyable types will still be impacted. Impacted in what way? They'll get the same result as they did previously. This changes std::is_copy_constructible to be more accurate and makes __move_if_noexcept work for the unordered containers. How does that affect boost::is_copy_constructible? It gives the wrong result for unordered_containers of non-copyable types, but already did, and it's not my responsibility to fix everyone else's traits :-) > Did > your idea in comment #15 not work? I don't think that would be conforming and would be a huge amount of work to replace every constructor in vector and forward_list (and every other container as they are updated to be allocator-aware) with a template constructor. I'm not going to work on that solution, and I won't approve patches to do that without a lot of persuasion. I still do want to use SFINAE to remove allocator_traits<A>::construct(args) from participating in overload resolution when A().construct(args) is not valid and is_constructible<A::value_type, args> is false, which I hope is conforming, and would allow a better solution similar to comment 17, by deleting the unordered_xxx copy ctor. I'll revisit the patch tonight.
