@mei Not "breaking" as in "won't compile", but as in "the API you have written now has a different set of guarantees compared to what it did before, in a manner where behavior relying on the old assumptions will be triggered differently or not at all". Idk. I think I would consider this a breaking change, even if both compile. Therefore, I do think that the planned(?) change to represent this as "doesn't compile" makes a lot of sense