https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116130
--- Comment #10 from rguenther at suse dot de <rguenther at suse dot de> --- On Tue, 30 Jul 2024, jakub at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116130 > > --- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- > (In reply to rguent...@suse.de from comment #8) > > IMO this asks for metadata on each (standard) attribute whether it > > merges conservatively by union or by intersection since there are > > two classes of attributes. > > Well, doing so would violate the standard, which added a clear: > "If one of the types has a standard attribute, the composite type also has > that > attribute." We do violate the standard in other places - IMO QOI/safety should be a priority. I view the above as a defect. I'd at least emit an unconditional diagnostic when doing this kind of merging in any place (also for GCC type/decl attributes). > > And then there's things like [[gnu::warn_unused_result]] where > > it's not at all clear what is "conservative" (drop valid diagnostics > > or introduce broken ones?). > > gnu::warn_unused_result is not a standard attribute (but currently we merge > all > of them), but more importantly it isn't a function type attribute, but > function > decl attribute. Those aren't merged. Huh, that's an odd distinction. I hope we document this somewhere in a way understandable by users since IIRC it's not possible to distinguish those syntactically when placed in a function declaration?
