dblaikie added a comment. In D140860#4028089 <https://reviews.llvm.org/D140860#4028089>, @hazohelet wrote:
> As you point out, enhancement may be more accurate than bug fix. > There are rare cases where enabling a warning for missing parentheses in > `constexpr` logical expressions can be helpful, I think. For example, > consider the following code: > > constexpr A = ...; > constexpr B = ...; > constexpr C = ...; > > static_assert(!(A && B || C)); > > In this case, the static assertion will only be successful if `(A && B || C)` > evaluates to `false`, which is equivalent to the following combinations of > values for `A`, `B`, and `C`: > > (A, B, C) = (T, F, F) (F, T, F) (F, F, F) > > Note that `T` means `true` and `F` means `false`. Here, `C` is always > `false`, so `A && B || C` matches the case of `a && b || 0`. Thus, the > warning is not issued before this patch. > If the programmer is not careful and assumes that `(A && B || C)` is > equivalent to `(A && (B || C))`, then they expect the values of `A`, `B`, and > `C` to also include the following combinations: > > (A, B, C) = (F, T, T) (F, F, T) > > This would require the programmer to consider additional, unnecessary > combinations after the successful static assertion. > > Enabling a warning for missing parentheses in this scenario could help > prevent the programmer from making this mistake. Fair enough. I guess the same argument applies to the non-static case too. I think it was original mostly motivated by people using `&& "This is the reason for the assert"` without parentheses around the LHS & that was generally fine. So, so long as a string literal still does the suppression, it's probably fine. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D140860/new/ https://reviews.llvm.org/D140860 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
