if let

main.rs

fn overflow(n: i32, max: i32) -> Option<i32> {
    if n > max {
        Some(n - max)
    } else {
        None
    }
}

fn main() {
    let n = 15;
    // instead of this
    match overflow(n, 10) {
        Some(overflow) => println!("The input value has gone {overflow} over the maximum"),
        _ => {}
    }
    // do this
    if let Some(overflow) = overflow(n, 10) {
        println!("The input value has gone {overflow} over the maximum")
    }
}