Use & in pattern binding to remove noisy dereferencing of copy types.

[purpleposeidon]

The following:

fn main() {
    let data = vec![1, 2, 3, 4, 5];
    for i in &data {
        if *i == 3 {
            println!("Hmm!");
        }
        if *i == 2 {
            println!("Ahh?");
        }
        if *i == 1 {
            println!("Wut?!");
        }
    }
}

is less noisily expressed as:

fn main() {
    let data = vec![1, 2, 3, 4, 5];
    for &i in &data {
        if i == 3 {
            println!("Hmm!");
        }
        if i == 2 {
            println!("Ahh?");
        }
        if i == 1 {
            println!("Wut?!");
        }
    }
}

and it's obviously shorter than .iter().cloned().