ychen added a comment. In D133683#3818804 <https://reviews.llvm.org/D133683#3818804>, @mizvekov wrote:
> In D133683#3818752 <https://reviews.llvm.org/D133683#3818752>, @ychen wrote: > >> I didn't add that because this patch is logically part of D128745 >> <https://reviews.llvm.org/D128745> which has a release note already. > > Okay, I see that the existing release note entry talks just about > implementing those DRs without going specific, so that is fine. > It does not mention that DR1432 implementation is tentative as there is no > published resolution though. > >> I think GCC is the one that is not conforming. MSVC agrees it is ambiguous >> (https://godbolt.org/z/T5zbxaTYq). Basically, only the first parameter is >> considered for partial ordering. >> (https://eel.is/c++draft/temp.deduct.partial#3.1) > > I could totally buy that the GCC behavior is accidental, but it does make > sense, with the idea behind DR1432, that we should prefer the first overload > because that deduction is simpler, or because it does not deduce a parameter > pack. > > If there was a resolution, the answer here would be clear cut, but since > there isn't, we are making up our own rules and getting into a language > design discussion. > If you don't think that is clear cut, it's fine, we can move this discussion > elsewhere :) It is clear cut by https://eel.is/c++draft/temp.deduct.partial#3.1. It is orthogonal to the DRs implemented in D128745 <https://reviews.llvm.org/D128745> and here. https://godbolt.org/z/s49sqrabY : if you call `g(42,42)`, it would reveal that the function without pack indeed wins. It is ambiguous because the caller `g(42)` does not use the pack. So the wording prevents us from letting the non-pack version win. I do somewhat agree that it is more consistent and predictable to always consider all function parameters for partial ordering. Yeah, that needs a whole separate discussion on https://eel.is/c++draft/temp.deduct.partial#3.1. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D133683/new/ https://reviews.llvm.org/D133683 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
