rust/src/test/compile-fail/mut-pattern-internal-mutability.rs
2018-04-15 07:13:42 -04:00

31 lines
1.0 KiB
Rust

// Copyright 2015 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.
// revisions: ast mir
//[mir]compile-flags: -Z borrowck=mir
fn main() {
let foo = &mut 1;
let &mut x = foo;
x += 1; //[ast]~ ERROR cannot assign twice to immutable variable
//[mir]~^ ERROR cannot assign twice to immutable variable `x`
// explicitly mut-ify internals
let &mut mut x = foo;
x += 1;
// check borrowing is detected successfully
let &mut ref x = foo;
*foo += 1; //[ast]~ ERROR cannot assign to `*foo` because it is borrowed
//[mir]~^ ERROR cannot assign to `*foo` because it is borrowed
drop(x);
}