Quuxplusone added a comment. In https://reviews.llvm.org/D52137#1236053, @rsmith wrote:
> I think we can and should do better about false positives here. If you move > this check to SemaChecking, you can produce the warning in a context where > you know what the final type is -- I don't think there's any reason to warn > if the final type is signed and no wider than the promoted type of the > negation. I share your general concern about false positives, but in the specific case you mentioned— void use(int16_t x) uint8_t u8 = 1; use(-u8); —I think it'd be surprising to maybe 50% of average programmers that `x`'s received value wasn't `int16_t(255)` but rather `int16_t(-1)`. The only cases I'd personally consider "false positives" would be cases where `-u32` was being used as a convenient shorthand for `~u32 + 1` a.k.a. `(0u - u32)`... but maybe in those cases it wouldn't be much of a burden for the programmer to just accept a fixit to `(0u - u32)` and be done with it. https://reviews.llvm.org/D52137 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
