[Bug c++/99472] [modules] std=c++2b flag appears incompatible with C++20 module code

[nathan at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99472

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
indeed, also enabling modules test in 2b mode