#![allow(dead_code, deprecated, unused_variables, unused_mut)]
fn main() {
    let mut x = Some(42);
    let prev = x
        .take_if(|v| {
            if *v == 42 {
                *v += 1;
                false
            } else {
                false
            }
        });
    assert_eq!(x, Some(43));
    assert_eq!(prev, None);
    let prev = x.take_if(|v| *v == 43);
    assert_eq!(x, None);
    assert_eq!(prev, Some(43));
}