I::Item: Clone, J::Item: Clone triggers FP

[jendrikw]

Summary

This only happens when using both J::AssociatedType and one the types is Self.

Lint Name

type_repetition_in_bounds

Reproducer

I tried this code playground:

#[warn(clippy::type_repetition_in_bounds)]

trait T: Iterator {
    fn f<J>(self, _: J)
    where
        Self: Sized,
        Self::Item: Clone,
        J: Iterator,
        J::Item: Clone,
    {
    }
}

I saw this happen:

warning: this type has already been used as a bound predicate
 --> src/lib.rs:9:9
  |
9 |         J::Item: Clone,
  |         ^^^^^^^^^^^^^^
  |
note: the lint level is defined here
 --> src/lib.rs:1:8
  |
1 | #[warn(clippy::type_repetition_in_bounds)]
  |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  = help: consider combining the bounds: `J::Item: Clone + Clone`

I expected to see this happen:

No warning.

Version

rustc 1.57.0 (f1edd0429 2021-11-29)
binary: rustc
commit-hash: f1edd0429582dd29cccacaf50fd134b05593bd9c
commit-date: 2021-11-29
host: x86_64-unknown-linux-gnu
release: 1.57.0
LLVM version: 13.0.0

Additional Labels

No response

[jendrikw]

I've found another example: playground

#![warn(clippy::type_repetition_in_bounds)]

pub struct ZipAll<I: Iterator, J: Iterator>(I, J);

impl<I: Iterator, J: Iterator> ZipAll<I, J>
where
    I::Item: Clone,
    J::Item: Clone,
{}

[jendrikw]

I think this is a duplicate (but with a smaller example) of #7360.