ices/100689.rs: fixed with no errors

[github-actions]

Issue: rust-lang/rust#100689

#![feature(generic_associated_types)]

struct Foo<'a> {
    foo: &'a mut usize,
}

trait Bar<'a> {
    type FooRef<'b>
    where
        'a : 'b,
    ;
    fn uwu (
        foo: Foo<'a>,
        f: impl for<'b> FnMut(Self::FooRef<'b>),
    )
    ;
}
impl<'a> Bar<'a> for () {
    type FooRef<'b>
    =
        &'b Foo<'a>
    where
        'a : 'b,
    ;
    
    fn uwu (
        foo: Foo<'a>,
        mut f: impl for<'b> FnMut(&'b Foo<'a>), //relevant part
    )
    {
        f(&foo);
    }
}

fn main() {}

=== stdout ===
=== stderr ===
warning: the feature `generic_associated_types` has been stable since 1.65.0 and no longer requires an attribute to enable
 --> /home/runner/work/glacier/glacier/ices/100689.rs:1:12
  |
1 | #![feature(generic_associated_types)]
  |            ^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(stable_features)]` on by default

warning: field `foo` is never read
 --> /home/runner/work/glacier/glacier/ices/100689.rs:4:5
  |
3 | struct Foo<'a> {
  |        --- field in this struct
4 |     foo: &'a mut usize,
  |     ^^^
  |
  = note: `#[warn(dead_code)]` on by default

warning: 2 warnings emitted

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