65 lines
1.7 KiB
Rust
65 lines
1.7 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// This tests that we can't modify Box<&mut T> contents while they
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// are borrowed.
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#![feature(box_syntax)]
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struct A { a: isize }
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struct B<'a> { a: Box<&'a mut isize> }
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fn borrow_in_var_from_var() {
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let mut x: isize = 1;
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let y: Box<_> = box &mut x;
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let p = &y;
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let q = &***p;
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**y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
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drop(p);
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drop(q);
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}
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fn borrow_in_var_from_field() {
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let mut x = A { a: 1 };
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let y: Box<_> = box &mut x.a;
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let p = &y;
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let q = &***p;
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**y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
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drop(p);
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drop(q);
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}
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fn borrow_in_field_from_var() {
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let mut x: isize = 1;
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let y = B { a: box &mut x };
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let p = &y.a;
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let q = &***p;
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**y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
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drop(p);
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drop(q);
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}
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fn borrow_in_field_from_field() {
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let mut x = A { a: 1 };
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let y = B { a: box &mut x.a };
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let p = &y.a;
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let q = &***p;
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**y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
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drop(p);
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drop(q);
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}
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fn main() {
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borrow_in_var_from_var();
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borrow_in_var_from_field();
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borrow_in_field_from_var();
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borrow_in_field_from_field();
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}
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