https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86453
--- Comment #5 from Martin Sebor <msebor at gcc dot gnu.org> --- The attribute exclusion framework only excludes conflicting attributes if they aren't applied by their handler. It doesn't know how to undo changes that the handler makes, like modifying tree nodes in place. It would need to be extended to also let each handler detect the conflicts before making these kinds of changes.