rust/src/test/ui/error-codes/E0502.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)]
fn bar(x: &mut i32) {}
fn foo(a: &mut i32) {
    let ref y = a;
    bar(a); //~ ERROR E0502
}

fn main() { #![rustc_error] // rust-lang/rust#49855
}