Borrowed function

gistfile1.rs

fn inner(f: &fn(&mut int)) {
    let mut a = ~1;
    f(a);
}

fn borrow(b: &mut int, f: &fn(&mut int)) {
    f(b);
    f(b); // can reuse borrowed variable

    inner(f);  // shouldn't f be borrowed?

    // Why can't I reuse the borrowed reference to a function?
    // ** error: use of moved value: `f` **
    //f(b);        
}

fn main() {
    let mut a = ~1;
    print!("{}", (*a));
    borrow(a, |x: &mut int| *x+=1);
    print!("{}", (*a));
}