http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47668
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-02-09 19:01:03 UTC --- This certainly isn't high priority to fix, and I'm not sure what the best fix is given that G++ has problems with parsing the required typename (PR 14258) so I'm not going to change anything right away, I just wanted to record the issue
