https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53000
--- Comment #29 from Daniel Krügler <daniel.kruegler at googlemail dot com> --- (In reply to Paolo Carlini from comment #28) > Something is going wrong here: the bug is closed as fixed, but if I try to > enable in 20_util/common_type/requirements/sfinae_friendly_1.cc the lines > which require the bug to be fixed to pass, I'm still seeing a failure, for > the line: > > static_assert(is_type<std::common_type<const Ukn&&, volatile Ukn&&>, > Ukn>(), ""); > > Maybe Daniel or Jason can clarify?? Comparing this test with the current wording in 5.16 the assertion looks incorrect and should be doomed to fail - sorry! I'll check the remaining ones and will suggest a patch for it.