//@ run-pass fn borrow(x: &isize, f: F) where F: FnOnce(&isize) { f(x) } fn test1(x: &Box) { borrow(&*(*x).clone(), |p| { let x_a = &**x as *const isize; assert!((x_a as usize) != (p as *const isize as usize)); assert_eq!(unsafe{*x_a}, *p); }) } pub fn main() { test1(&Box::new(22)); }