http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41933
--- Comment #8 from Jason Merrill <jason at gcc dot gnu.org> 2012-04-16 19:21:13 UTC --- Created attachment 27172 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27172 incomplete patch Here's the beginning of work to implement this. A lot more will be needed.