Extending a class-bound type to conform to a protocol extended with `mutating` functions

[Jens]

@AnotherUser

I think it's a little odd that such an assumption would be permitted in Swift, seeing as nowhere anywhere does a class -bound type reassign itself... does it? (What would that even mean? Every pointer to it now points somewhere else? How does that work?)

I can kind of agree. I wrote a separate post asking about this. (It is possible to reassign self in a class, but not straight forwardly.)