I haven't been supper up to date with changes to rust-lang recently (I had seen that they are stabilizing if_let_rescope but didn't look into what it is, to much to do at work).

Through making if-let less syntax sugar for changing a implicit behavior people most likely didn't rely on but have problems with seems like a very good idea

My comment about this being hard to change was mainly about match. Not considering the option of making if-let less syntax sugary.

And in difference to if-let, for match people do (or at least did years ago in production code) rely on it.