#![feature(box_syntax)] | |
fn borrow<F>(v: &isize, f: F) where F: FnOnce(&isize) { | |
f(v); | |
} | |
fn box_imm() { | |
let mut v: Box<_> = box 3; | |
borrow(&*v, | |
|w| { //~ ERROR cannot borrow `v` as mutable | |
v = box 4; | |
assert_eq!(*v, 3); | |
assert_eq!(*w, 4); | |
}) | |
} | |
fn main() { | |
} |