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