I guess that it _would_ be possible to have a hard "edition lint" that would basically forbid you from _implementing_ description in a 2021 or whatever crate. I

I guess that it _would_ be possible to have a hard "edition lint" that would basically forbid you from _implementing_ description in a 2021 or whatever crate. It would still exist and be callable, but no new (non-default) implementations if you want to use new editions.