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//@ run-pass
// Checks that higher-ranked extern fn pointers implement the full range of Fn traits.
fn square(x: &isize) -> isize { (*x) * (*x) }
fn call_it<F:Fn(&isize)->isize>(f: &F, x: isize) -> isize {
(*f)(&x)
}
fn call_it_boxed(f: &dyn Fn(&isize) -> isize, x: isize) -> isize {
f(&x)
}
fn call_it_mut<F:FnMut(&isize)->isize>(f: &mut F, x: isize) -> isize {
(*f)(&x)
}
fn call_it_once<F:FnOnce(&isize)->isize>(f: F, x: isize) -> isize {
f(&x)
}
fn main() {
let x = call_it(&square, 22);
let x1 = call_it_boxed(&square, 22);
let y = call_it_mut(&mut square, 22);
let z = call_it_once(square, 22);
assert_eq!(x, square(&22));
assert_eq!(x1, square(&22));
assert_eq!(y, square(&22));
assert_eq!(z, square(&22));
}
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