http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56677
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-03-21 15:35:46 UTC --- That wouldn't help. The requirement is that the Period template argument is a ratio. In GCC 4.7 ratio_divide is not a ratio. Whether ratio_divide::type is a ratio or not doesn't change the fact that ratio_divide is not a ratio and therefore not a suitable template argument for duration. To make it work we'd also need to make duration::period a typedef for either _Period or _Period::type and alter the two static assertions to use period not _Period, which is doable but I'm not convinced it's worth fixing in the stable release branch. I might look into it later.
