Almost every major release of rust stabilizes new library methods. For example, the latest major release (1.93) stabilized Vec::into_raw_parts. This isn’t gated by an edition. So if you had a trait with a method “into_raw_parts” which you had defined on Vec, after updating to 1.93 or later your code will either fail to compile, or start running different code when that method is called.

Sorry, I meant to write “method resolution”, not inference. This isn’t the same issue as type inference (though indeed, stdlib changes can break that too)