https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107405
--- Comment #10 from Jiri Slaby <jirislaby at gmail dot com> --- (In reply to Jonathan Wakely from comment #9) > (In reply to Jiri Slaby from comment #4) > > Another question is why B is affected by A at all? Also sizeof of that enum > > (if one gives it a name) is 8 with gcc-13. That is not allowed by the > > standard, IMO. > > C99, C11, and C17 all say: > > "The expression that defines the value of an enumeration constant shall be > an integer > constant expression that has a value representable as an int." > > So enum { A = 0xffffffff } is a constraint violation and not allowed by the > standard anyway. Such code was always non-conforming and relying on an > (undocumented?) GCC extension, so the standard has nothing to say about the > type. Ah, that's correct. So the question then is: is it a feature we can rely on (even if undocumented -- can the behavior can be documented in gcc?), or we should drop enum uses for values > MAX_INT?