No need to ref to function

What it does

Suggests to remove a & from the code in one case.

Advantage

Simpler code.

Drawbacks

I don't know if there are drawbacks.

Example

#![warn(clippy::all)]
#![warn(clippy::nursery)]
#![warn(clippy::pedantic)]

fn exchange_sort(arr: &mut [u32], is_less: &impl Fn(&u32, &u32) -> bool) {
    for i in 0 .. arr.len() - 1 {
        for j in i + 1 .. arr.len() {
            if is_less(&arr[j], &arr[i]) {
                arr.swap(i, j);
            }
        }
    }
}

const fn my_less(a: &u32, b: &u32) -> bool {
    *a < *b
}

fn main() {
    let mut a = [1, 10, 3, 2, 0, 12];
    exchange_sort(&mut a, &my_less);
    println!("{a:?}"); // Prints: [0, 1, 2, 3, 10, 12]
}

Could be written as:

#![warn(clippy::all)]
#![warn(clippy::nursery)]
#![warn(clippy::pedantic)]

fn exchange_sort(arr: &mut [u32], is_less: impl Fn(&u32, &u32) -> bool) {
    for i in 0 .. arr.len() - 1 {
        for j in i + 1 .. arr.len() {
            if is_less(&arr[j], &arr[i]) {
                arr.swap(i, j);
            }
        }
    }
}

const fn my_less(a: &u32, b: &u32) -> bool {
    *a < *b
}

fn main() {
    let mut a = [1, 10, 3, 2, 0, 12];
    exchange_sort(&mut a, my_less);
    println!("{a:?}"); // Prints: [0, 1, 2, 3, 10, 12]
}

Comparison with existing lints

No response

Additional Context

No response

No files, tests, or entry points are named. Start by reviewing the two Rust examples and clarify the exact lint scope and expected behavior; done should include an agreed implementation and tests covering the proposed transformation.