https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69365
Bug ID: 69365 Summary: LWG DR2367 (constrained pair default constructor) Product: gcc Version: 5.3.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: Casey at Carter dot net Target Milestone: --- There's a bug report for range-v3 (https://github.com/ericniebler/range-v3/issues/275) that results from libstdc++ in the GCC-5 branch not implementing the resolution of LWG2367 (constraining the default constructor of std::pair & std::tuple). I'm aware that 2367 is fixed on trunk - is there any possibility of the fix being backported to gcc-5-branch?