Useless by ref lint

What it does

Helps remove some useless & from the code.

Advantage

Simpler code

Drawbacks

I don't know

Example

#![warn(clippy::all)]
#![warn(clippy::nursery)]
#![warn(clippy::pedantic)]
fn main() {
    let items = [(1, 2), (3, 4)];
    for &(x, y) in &items.map(|(x, y)| (-x, -y)) {
        println!("{x} {y}");
    }
}

Could be written as:

#![warn(clippy::all)]
#![warn(clippy::nursery)]
#![warn(clippy::pedantic)]
fn main() {
    let items = [(1, 2), (3, 4)];
    for (x, y) in items.map(|(x, y)| (-x, -y)) {
        println!("{x} {y}");
    }
}

No source file, test, or entry point is named. Start by comparing the two Rust examples and define which uses of a leading ampersand are redundant. Done should be a Clippy lint that reports the demonstrated case and has clear behavior for its supported scope.