`new_ret_no_self` false positive when returning `impl Trait<Self>`

[nbdd0121]

Lint name: new_ret_no_self

pub struct Foo;

impl Foo {
    pub fn new() -> impl Into<Self> {
        Foo
    }
}

causes a warning where it shouldn't. impl Into here can be any trait that has Self in generic arguments.

This is similar to #4359 but instead of Future<Output = Self> it's Into<Self>. #4365's title implies that this should be allowed but actually it only deals with associated types, not type parameters.

cargo clippy -V: 0.1.54 (2021-06-09 eab201d)

[nbdd0121]

@rustbot claim