[Bug c++/98885] [modules] forward declaration of classes prevent them from being exported at the point of actual declaration

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98885

--- Comment #3 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
module partitions are probably what you want for such mutually dependent types.