http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54769
--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> 2012-10-02 06:04:56 UTC --- In C++03 this was supposed to be ill-formed, but - as Mike Miller explained to me - with the acceptance of CWG 1111 (no kidding ;-)) http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1111 this code should now become accepted.