I think it would be useful to give an example of the kind of semantics that would be desirable to change, and where people might think that it should be possibl

I think it would be useful to give an example of the kind of semantics that would be desirable to change, and where people might think that it should be possible to change at an edition boundary. I’m not very sure, but maybe something like unforgettable types? Or linear types? Maybe negative trait bounds, or specialization?