https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80796
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- That's intentional, because they're not in the C+17 draft. They were removed by http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0433r2.html