ices/68090.rs: fixed with no errors

[github-actions]

Issue: rust-lang/rust#68090

pub fn main() {
    |_: ARef| ();
}

type ARef<'a> = &'a <() as ArrayLength>::ArrayType;

trait ArrayLength {
    type ArrayType;
}

impl ArrayLength for () {
    type ArrayType = u8;
}

=== stdout ===
=== stderr ===
warning: unused closure that must be used
 --> /home/runner/work/glacier/glacier/ices/68090.rs:2:5
  |
2 |     |_: ARef| ();
  |     ^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_must_use)]` on by default
  = note: closures are lazy and do nothing unless called

warning: 1 warning emitted

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