Ha, despite supporting all the flags for handling modules, and despite advertising being based on Clang 17, the latest AppleClang actually doesn’t parse C++20 modules syntax at all under any conditions. Ie, it doesn’t know about the module keyword no matter what set of flag magic you pass it.
Well so much for that plan.
This is precisely why I had the compiler detection logic in the scope cmake – yes I’m afraid it feels like a horrible hack, but well things often don’t quite live up to whats on the tin. In the case of scope I only found Clang19+ and g++15 to be viable (msvc is probably fine but scope isn’t ported there yet). Clang 17 at this point is a quite old compiler so I’m not suprised that it doesn’t work.