// run-pass fn f(mut y: Box<isize>) { *y = 5; assert_eq!(*y, 5); } fn g() { let frob = |mut q: Box<isize>| { *q = 2; assert_eq!(*q, 2); }; let w = Box::new(37); frob(w); } pub fn main() { let z = Box::new(17); f(z); g(); }