https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93458
--- Comment #3 from Iain Sandoe <iains at gcc dot gnu.org> --- (In reply to Tom Tromey from comment #1) > I think it's invalid. Yes, it's invalid, unfortunately, one cannot write a C++20 coroutine in such a simple form; they need supporting methods that are found through the class type they instantiate. BTW, did you include <coroutine> ? (FAOD: it would still be broken if you did, but ISTM we might at some point add a hint that if the traits can't be found, you probably forgot that).
