#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::sync::atomic::{AtomicBool, Ordering};
fn main() {
    let x = AtomicBool::new(false);
    assert_eq!(
        x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, | _ | None), Err(false)
    );
    assert_eq!(
        x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, | x | Some(! x)), Ok(false)
    );
    assert_eq!(
        x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, | x | Some(! x)), Ok(true)
    );
    assert_eq!(x.load(Ordering::SeqCst), false);
}