http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48940
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-05-10 09:08:39 UTC --- I assume you're talking about binding the A& to a B object without an accessible copy constructor? That was the subject of a Defect Report against C++03 so has been fixed in G++, therefore not a bug. No temporary is created, so no copy constructor is needed http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#589
