Confusing/inconsistent lifetime error with == on types with different covariant lifetimes

[jseyfried]

#[derive(Eq, PartialEq)]
struct S<'a>(&'a ());

fn f<'a, 'b>(a: S<'a>, b: S<'b>) {
    a.eq(&b); // This is OK
    a == b; // This errors that 'a cannot outlive 'b so that the expression is assignable
}

[Freyskeyd]

hello,

this is related to #45435 cc @eddyb

[jseyfried]

Thanks @Freyskeyd! Closing as duplicate of #45425.