[Bug c/86453] [8/9 Regression] error: type variant differs by TYPE_PACKED in free_lang_data since r255469

[msebor at gcc dot gnu.org]

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.