|  | //@ only-x86_64 | 
|  | use std::sync::atomic::{AtomicUsize, Ordering}; | 
|  |  | 
|  | fn main() { | 
|  | // `compare_exchange` (not weak) testing | 
|  | let x = AtomicUsize::new(0); | 
|  |  | 
|  | // Allowed ordering combos | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::Relaxed); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::Acquire); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::SeqCst); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::Relaxed); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::Acquire); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::SeqCst); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::Relaxed); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::Acquire); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::SeqCst); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::Relaxed); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::Acquire); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::SeqCst); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::Relaxed); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::Acquire); | 
|  | let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::SeqCst); | 
|  |  | 
|  | // AcqRel is always forbidden as a failure ordering | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::AcqRel); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::AcqRel); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::AcqRel); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::AcqRel); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::AcqRel); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  |  | 
|  | // Release is always forbidden as a failure ordering | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::Release); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::Release); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::Release); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::Release); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::Release); | 
|  | //~^ ERROR `compare_exchange`'s failure ordering may not be `Release` or `AcqRel` | 
|  | } |