AaronBallman wrote: > > There's some danger here. _BitInt is a C23 feature as are enumerations with > > a fixed underlying type. Enumerations with a fixed underlying type > > explicitly disallow using a bit-precise integer type as the underlying > > type. See C23 6.7.2.2p4, which says in part, "For all the integer constant > > expressions which make up the values of the enumeration constants, there > > shall be a type capable of representing all the values that is a standard > > or extended signed or unsigned integer type, or char.". > > Thank you for pointing out to this! But it's not clear to me whether this was > an explicit decision to not add bit-precise integers here, or just nobody > cared enough to push for that. Because use case we have on our hands seems > legit to me.
Explicit decision: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3030.htm#design-bit.precise.integers -- we should add that diagnostic at some point. :-D The biggest concern I had is that bit-precise integer types do not undergo integer promotions, but enumerations do. So it's unclear what the expectations are in this case. Should `enum Foo : unsigned _BitInt(8);` promote to `int` like `unsigned char` would, or should it not promote like `unsigned _BitInt(8)` would? https://github.com/llvm/llvm-project/pull/69104 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
