src/test/run-pass/mir_autoderef.rs

// Copyright 2016 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.

#![feature(rustc_attrs)]

use std::ops::{Deref, DerefMut};

pub struct MyRef(u32);

impl Deref for MyRef {
    type Target = u32;
    fn deref(&self) -> &u32 { &self.0 }
}

impl DerefMut for MyRef {
    fn deref_mut(&mut self) -> &mut u32 { &mut self.0 }
}


#[rustc_mir]
fn deref(x: &MyRef) -> &u32 {
    x
}

#[rustc_mir]
fn deref_mut(x: &mut MyRef) -> &mut u32 {
    x
}

fn main() {
    let mut r = MyRef(2);
    assert_eq!(deref(&r) as *const _, &r.0 as *const _);
    assert_eq!(deref_mut(&mut r) as *mut _, &mut r.0 as *mut _);
}