| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // Checks that the Fn trait hierarchy rules do not permit |
| // Fn to be used where FnMut is implemented. |
| |
| #![feature(fn_traits, unboxed_closures)] |
| #![feature(overloaded_calls)] |
| |
| use std::ops::{Fn,FnMut,FnOnce}; |
| |
| struct S; |
| |
| impl FnMut<(isize,)> for S { |
| extern "rust-call" fn call_mut(&mut self, (x,): (isize,)) -> isize { |
| x * x |
| } |
| } |
| |
| impl FnOnce<(isize,)> for S { |
| type Output = isize; |
| |
| extern "rust-call" fn call_once(mut self, args: (isize,)) -> isize { self.call_mut(args) } |
| } |
| |
| fn call_it<F:Fn(isize)->isize>(f: &F, x: isize) -> isize { |
| f.call((x,)) |
| } |
| |
| fn main() { |
| let x = call_it(&S, 22); |
| //~^ ERROR E0277 |
| } |