[Bug libstdc++/56283] std::result_of does not gracefully SFINAE (not define ::type)

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56283

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-02-11 10:05:58 UTC ---
You're looking at a post-C++11 draft, not at the standard. The change was made
by http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3462.html and GCC
4.8 already implements the new behaviour, but 4.7 isn't going to.