compnerd added inline comments.
================ Comment at: clang/include/clang/Basic/AttrDocs.td:3394 +parameter. Currently, the error parameter is always the last parameter of type +``NSError**`` or ``CFErrorRef*``. Swift will remove the error parameter from +the imported API. When calling the API, Swift will always pass a valid address ---------------- aaron.ballman wrote: > compnerd wrote: > > rjmccall wrote: > > > compnerd wrote: > > > > aaron.ballman wrote: > > > > > Canonical type or are typedefs to these types also fine? May want to > > > > > mention that the type has to be cv-unqualified, but I do wonder > > > > > whether something like `NSError * const *` is fine. > > > > I am definitely not the authority on this, but I believe that the > > > > common thing is to take `NSError **` or `CFErrorRef **` by canonical > > > > name. The cv-qualified versions, except on the outermost pointer, is > > > > something that can be treated as valid, though it is certainly > > > > extremely unusual. I've added test cases for them as well. > > > `NSError * const *` actually does not really work; the whole point is > > > that this is an out-parameter. > > Oh right, its the `const NSError ** const` that can work, because the outer > > pointer can be non-mutable as it is a pointer by-reference scenario. > > Should we diagnose the `NSError * const *` case then? Any `const` > > qualified value is really unidiomatic to say the least. > I think we should diagnose (as an error) any case that can't work. > > I think it may make sense to diagnose (as a warning) any case where we want > to ignore the qualifiers, in case we want to give semantics to those > qualifiers in this situation later. So this means we'd error on `NSError * > const *` but warn and ignore the qualifiers on `volatile NSError **`. > However, I don't insist on warning in this case unless there's a situation > that the user might actually appreciate the warning because it matters (it's > not clear to me if such a situation exists). Also, it's not clear to me > whether we should or should not warn on a `restrict`-qualified pointer. I think that the newer diagnostics would make sense as a follow up improvement in the case that @rjmccall believe that they would be useful to users. As John mentioned, `const` is rarely used with ObjectiveC, so the use of that is pretty unidiomatic. In fact, trying to return the error would cause a warning in the first place (due to the assignment of a value to a `const` parameter). Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D87331/new/ https://reviews.llvm.org/D87331 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
