rust/src/test/compile-fail/borrowck-issue-14498.rs

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// 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.
// This tests that we can't modify Box<&mut T> contents while they
// are borrowed.
2015-01-08 02:53:58 +00:00
#![feature(box_syntax)]
struct A { a: int }
struct B<'a> { a: Box<&'a mut int> }
fn borrow_in_var_from_var() {
let mut x: int = 1;
let y = box &mut x;
let p = &y;
let q = &***p;
**y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
drop(p);
drop(q);
}
fn borrow_in_var_from_field() {
let mut x = A { a: 1 };
let y = box &mut x.a;
let p = &y;
let q = &***p;
**y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
drop(p);
drop(q);
}
fn borrow_in_field_from_var() {
let mut x: int = 1;
let y = B { a: box &mut x };
let p = &y.a;
let q = &***p;
**y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
drop(p);
drop(q);
}
fn borrow_in_field_from_field() {
let mut x = A { a: 1 };
let y = B { a: box &mut x.a };
let p = &y.a;
let q = &***p;
**y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
drop(p);
drop(q);
}
fn main() {
borrow_in_var_from_var();
borrow_in_var_from_field();
borrow_in_field_from_var();
borrow_in_field_from_field();
}