shafik added a comment. In D150226#4353911 <https://reviews.llvm.org/D150226#4353911>, @aaron.ballman wrote:
> In D150226#4353905 <https://reviews.llvm.org/D150226#4353905>, @dim wrote: > >> I submitted a similar workaround for the FreeBSD devel/gdb port, via >> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=271045 that also applies >> `-Wno-enum-constexpr-conversion`. As the upstream commit message said, they >> didn't see any other good way to get rid of the warning, so if there is a >> workaround clang is OK with, that would be nice. Still, I don't really >> understand what the value is of making this warning into an error, that is >> not suppressible? > > One of the major selling points to `constexpr` functions in C++ is that they > cannot contain UB -- if your code compiles, it is correct. This bug that > we've fixed was another instance of us accidentally allowing UB in a constant > expression context when we shouldn't have. FWIW, I pointed out a reasonable > workaround for the freebsd issue: https://reviews.llvm.org/D150226#4342516 Also note, one of the bugs I reference shows how this breaks SFINAE: https://github.com/llvm/llvm-project/issues/57176 and that is not easily fixable. So this is non-conforming since it breaks valid code. There are two basic work arounds. One give the enum a fixed underlying type: enum E : int {} which will give the whole range of values to work with or if there is a one specific error value they want they can explicitly add an error enumerator and make the error value explicit. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D150226/new/ https://reviews.llvm.org/D150226 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
