http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11764
--- Comment #23 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-02-20 17:03:00 UTC --- No, that's valid. In the nested-name-specifier the second A only considers namespaces, types and templates whose specializations are types ([basic.lookup.qual]) so it doesn't name the constructor.
