https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77537
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Known to work| |5.4.0 Target Milestone|--- |6.3 Summary|pair constructors do not |[6 Regression] pair |properly SFINAE |constructors do not | |properly SFINAE Known to fail| |6.2.0 --- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> --- With 5.4 only one of assertions failed: pair.cc:11:1: error: static assertion failed: FAIL static_assert(!std::is_constructible<P<moveonly>, int, moveonly&>::value, "FAIL"); ^ So I'm marking this as a regression.