// run-rustfix fn main() { let x = std::sync::Mutex::new(1usize); x.lock().unwrap() = 2; //~^ ERROR invalid left-hand side of assignment x.lock().unwrap() += 1; //~^ ERROR binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>` let mut y = x.lock().unwrap(); y = 2; //~^ ERROR mismatched types y += 1; //~^ ERROR binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>` }