"struct is never used" when Self is used to name the type

[jonas-schievink]

struct S;

impl Clone for S {
    fn clone(&self) -> Self { loop{} }
    // Doesn't warn:
    //fn clone(&self) -> S { loop{} }
}

fn main() {}

Prints a warning that S isn't used, but doesn't warn when naming S explicitly.

[Gankra]

It seems to me that not warning when it's used explicitly in a trait implementation is the real bug here.

[arielb1]

@gankro

You can gain access to S via inference guessing.

[Mark-Simulacrum]

Closing in favor of (what I think is) a duplicate: #18290.