src/test/run-pass/issue-16774.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11
  12 #![allow(unknown_features)]
  13 #![feature(box_syntax)]
  14 #![feature(box_patterns)]
  15
  16 use std::ops::{Deref, DerefMut};
  17
  18 struct X(Box<isize>);
  19
  20 static mut DESTRUCTOR_RAN: bool = false;
  21
  22 impl Drop for X {
  23     fn drop(&mut self) {
  24         unsafe {
  25             assert!(!DESTRUCTOR_RAN);
  26             DESTRUCTOR_RAN = true;
  27         }
  28     }
  29 }
  30
  31 impl Deref for X {
  32     type Target = isize;
  33
  34     fn deref(&self) -> &isize {
  35         let &X(box ref x) = self;
  36         x
  37     }
  38 }
  39
  40 impl DerefMut for X {
  41     fn deref_mut(&mut self) -> &mut isize {
  42         let &mut X(box ref mut x) = self;
  43         x
  44     }
  45 }
  46
  47 fn main() {
  48     {
  49         let mut test = X(box 5);
  50         {
  51             let mut change = || { *test = 10 };
  52             change();
  53         }
  54         assert_eq!(*test, 10);
  55     }
  56     assert!(unsafe { DESTRUCTOR_RAN });
  57 }