https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109323
--- Comment #5 from Enrico Maria De Angelis <enricomaria.dean6elis at gmail dot com> --- I've asked some feeback here https://stackoverflow.com/questions/75891694/is-it-legal-for-a-coroutines-promise-type-to-lack-both-return-void-and-return-v
