1 use parking_lot::RwLock; 2 3 struct Lock(RwLock<i32>); 4 5 #[test] issue_392()6fn issue_392() { 7 let lock = Lock(RwLock::new(0)); 8 let mut rl = lock.0.upgradable_read(); 9 rl.with_upgraded(|_| { 10 println!("lock upgrade"); 11 }); 12 rl.with_upgraded(|_| { 13 println!("lock upgrade"); 14 }); 15 } 16