rjmccall added a comment. In D116203#3434515 <https://reviews.llvm.org/D116203#3434515>, @cjdb wrote:
> In D116203#3431612 <https://reviews.llvm.org/D116203#3431612>, @rjmccall > wrote: > >> In D116203#3430332 <https://reviews.llvm.org/D116203#3430332>, >> @aaron.ballman wrote: >> >>> In D116203#3425512 <https://reviews.llvm.org/D116203#3425512>, @cjdb wrote: >>> >>>> I've noticed that libstdc++ has `using __remove_cv = typename >>>> remove_cv<T>::type`, which causes Clang to chuck a wobbly. Changing from >>>> `KEYWORD` to `TYPE_TRAIT_1` didn't seem to fix anything. >>>> Is there a way we can work around this, or should we just rename >>>> `__remove_cv` and friends to something else? >>> >>> You could work around it by taking note that you're in a libstdc++ system >>> header and do a special dance, but because these are in the >>> implementation's namespace, I think it's probably kinder for everyone to >>> just pick a different name. > > I was hoping we could do something similar to `struct __remove_cv` which > would issue a warning? > >>> If you wanted to be especially mean, you could go with `__remove_cvr`, but >>> I'd suggest `__remove_cv_qualifiers` instead. However, what about >>> `restrict` qualifiers? We support them in C++: >>> https://godbolt.org/z/11EPefhjf >> >> Along with a fair number of other vendor qualifiers, yeah. I think you have >> to make a policy decision about whether the intent of `std::remove_cv` is >> really to just remove CV qualifiers or to produce an unqualified type (at >> the outermost level). The former is probably more defensible, even if it >> makes the transform less useful in the presence of extended qualifiers. > > I'm partial to `std::remove_cv` being faithful to its name, unless existing > implementations do something else already. I don't mind adding support for > the other stuff, but if there's more than just add/remove `restrict`, we're > going to have a combinatorial explosion for removes. Is there an alternate > way we can approach this? > Possibly: > > template<class T> > using remove_const_t = __remove_qualifiers(T, const); > > > template<class T> > using remove_reference_t = __remove_qualifiers(T, &, &&); > > template<class T> > using remove_rcvref_t = __remove_qualifiers(T, const, volatile, restrict, > &, &&); // rcv instead of cvr to prevent a typo with remove_cvref_t I don't think it's worth adding that parsing complexity for a builtin that we expect to only be used in system headers. Let's just remove `const` and `volatile` and leave other qualifiers in place. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D116203/new/ https://reviews.llvm.org/D116203 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
