erichkeane 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?
Ooof, yeah, this needs to be ill-formed, I'd never thought of that when implementing it. 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
