rust/src/test/compile-fail/trait-impl-method-mismatch.rs

// Copyright 2012 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.


trait Mumbo {
    fn jumbo(&self, x: &usize) -> usize;
}

impl Mumbo for usize {
    // Cannot have a larger effect than the trait:
    unsafe fn jumbo(&self, x: &usize) { *self + *x; }
    //~^ ERROR method `jumbo` has an incompatible type for trait
    //~| expected type `fn
    //~| found type `unsafe fn
}

fn main() {}