http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52114
--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-02-04 22:49:17 UTC --- Thanks Daniel. Ben, I know SFINAE ;) what I was looking for is something *in the library* chapters saying somehow explicitly that for overload resolution purposes or other QoI purposes late return types are fine (vs the letter of the specs in terms of return types)