https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83503
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- If you mean it as a coding style warning (at least for const/pure), then it is at least worded incorrectly, there is no conflict between those and if what you do is that you ignore const attribute because earlier decl had pure attribute, then regardless of -w/-Wattributes/-Wno-attributes etc. you've undesirably changed behavior of something that was well defined before.
