#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(bool_to_result)]
fn main() {
    let mut a = 0;
    let mut function_with_side_effects = || {
        a += 1;
    };
    assert!(true.ok_or(function_with_side_effects()).is_ok());
    assert!(false.ok_or(function_with_side_effects()).is_err());
    assert_eq!(a, 2);
}