1 // MutexGuard<Cell<i32>> must not be Sync, that would be unsound.
5 fn test_sync<T: Sync>(_t: T) {}
9 let m = Mutex::new(Cell::new(0i32));
10 let guard = m.lock().unwrap();
12 //~^ ERROR `std::cell::Cell<i32>` cannot be shared between threads safely [E0277]