https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94765
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Keywords| |rejects-valid Status|UNCONFIRMED |NEW Last reconfirmed| |2020-04-25 --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- https://gcc.gnu.org/projects/cxx-status.html says that P1907R1 is supported since GCC 9, which seems unlikely when P1907R1 wasn't approved until 6 months after GCC 9.1 was released. That page also says that the relevant feature test macro check is __cpp_nontype_template_parameter_class >= 201806, which is wrong because the check for P1907R1 is __cpp_nontype_template_args >= 201911, and GCC defines: #define __cpp_nontype_template_args 201411L I think it's a doc bug, and the feature is not implemented yet.