https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65269
--- Comment #3 from GK <hgkamath at hotmail dot com> --- built commit e90da6bc78cf84e8b11680171aba9a58abc68fb1 2015-03-03 Andrew Sutton <andrew.n.sut...@gmail.com> origin compile error shifts to origin/core/concepts.hpp error: expected primary-expression before ‘;’ token Line 63 //Common_type<Ts...>; // FIXME: This better be a type requirement. true; or later to concept bool Incrementable() origin/sequence/concepts.hpp Line 78 //Difference_type<I>; Line 218 //Iterator_type<R>; //Sentinel_type<R>; Seems to me that return requires() as yet does not do "type requirement" as mentioned in n3701.pdf, pg 6