rjmccall added a comment. In D56735#1359590 <https://reviews.llvm.org/D56735#1359590>, @Anastasia wrote:
> In D56735#1358222 <https://reviews.llvm.org/D56735#1358222>, @rjmccall wrote: > > > Is there a reason not to just do `T1.getQualifiers() == T2.getQualifiers()`? > > > I tried this but it causes ObjC test to fail > test/SemaObjCXX/arc-overloading.mm. > > 38 // Simple overloading > 39 int &f2(id __strong const *); // expected-note{{candidate function}} > 40 float &f2(id __autoreleasing const *); // expected-note{{candidate > function}} > 41 > 42 void test_f2() { > 43 id __strong *sip; > 44 id __strong const *csip; > 45 id __weak *wip; > 46 id __autoreleasing *aip; > 47 id __unsafe_unretained *uip; > 48 > 49 // Prefer non-ownership conversions to ownership conversions. > 50 int &ir1 = f2(sip); > 51 int &ir2 = f2(csip); > 52 float &fr1 = f2(aip); > 53 > 54 f2(uip); // expected-error{{call to 'f2' is ambiguous}} > 55 } > > > Clang fails to resolve the overloads: > > error: 'error' diagnostics seen but not expected: > File /data/llvm/llvm/tools/clang/test/SemaObjCXX/arc-overloading.mm Line > 50: call to 'f2' is ambiguous > File /data/llvm/llvm/tools/clang/test/SemaObjCXX/arc-overloading.mm Line > 52: call to 'f2' is ambiguous > error: 'note' diagnostics seen but not expected: > File /data/llvm/llvm/tools/clang/test/SemaObjCXX/arc-overloading.mm Line > 39: candidate function > File /data/llvm/llvm/tools/clang/test/SemaObjCXX/arc-overloading.mm Line > 40: candidate function > File /data/llvm/llvm/tools/clang/test/SemaObjCXX/arc-overloading.mm Line > 39: candidate function > File /data/llvm/llvm/tools/clang/test/SemaObjCXX/arc-overloading.mm Line > 40: candidate function > > > Since CVR quals for both overloads of `f2` are the same it didn't continue > ranking the other qualifiers before. But now when it continues looking at the > other qualifiers it finds that `__strong` and `__autoreleasing` are disjoint > and exits at the following return statement in > `CompareQualificationConversions`: > > } else { > // Qualifiers are disjoint. > return ImplicitConversionSequence::Indistinguishable; > } > > > I feel the logic here doesn't apply to this case because it doesn't take into > account that for the passed in function argument there is no ownership > qualification conversion for one of the overloads. But I don't have a good > idea how to fix this easily other than just keep fast pathing ObjC qual here. > > May be if we add a separate qualification conversion for ObjC ownership > qualification only we will end up with more conversion steps for one overload > and therefore it will be possible to resolve the ambiguity? Do you have any > other suggestions or do you think someone else could help? For now, let's just remove the ownership qualifiers before comparing and leave a comment explaining that considering them here seems to interfere with the ARC overload rule. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D56735/new/ https://reviews.llvm.org/D56735 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
