False positive for `use_self` when using an associated type instead of the type itself.

[DDOtten]

A simple example of this is:

trait Foo {
    type Bar;
}

impl Foo for usize {
    type Bar = u8;
}

impl<T: Foo> Foo for Option<T> {
    type Bar = Option<T::Bar>;
}

here is the playground link.

[flip1995]

Related to #1993. There is a WIP PR #1997 with a fix, but hasn't been completed for a few months.

[gnzlbg]

Another example:

#![warn(clippy::use_self)]

pub trait NonZeroT {
    type T;
}
impl NonZeroT for i32 {
    type T = std::num::NonZeroU32;
}

https://play.rust-lang.org/?version=stable&mode=debug&edition=2015&gist=9926807d25af6d50d9b34139bd1c27ff