src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.rs

// Tests that unsafe extern fn pointers do not implement any Fn traits.

use std::ops::{Fn,FnMut,FnOnce};

extern "C" fn square(x: &isize) -> isize { (*x) * (*x) }

fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }

fn a() {
    let x = call_it(&square, 22);
    //~^ ERROR E0277
    //~| ERROR expected
}

fn b() {
    let y = call_it_mut(&mut square, 22);
    //~^ ERROR E0277
    //~| ERROR expected
}

fn c() {
    let z = call_it_once(square, 22);
    //~^ ERROR E0277
}

fn main() { }