src/test/run-pass/issue-16492.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 // ignore-pretty
  12
  13 #![feature(unsafe_destructor)]
  14
  15 use std::rc::Rc;
  16 use std::cell::Cell;
  17
  18 struct Field {
  19     number: uint,
  20     state: Rc<Cell<uint>>
  21 }
  22
  23 impl Field {
  24     fn new(number: uint, state: Rc<Cell<uint>>) -> Field {
  25         Field {
  26             number: number,
  27             state: state
  28         }
  29     }
  30 }
  31
  32 #[unsafe_destructor] // because Field isn't Send
  33 impl Drop for Field {
  34     fn drop(&mut self) {
  35         println!("Dropping field {}", self.number);
  36         assert_eq!(self.state.get(), self.number);
  37         self.state.set(self.state.get()+1);
  38     }
  39 }
  40
  41 struct NoDropImpl {
  42     _one: Field,
  43     _two: Field,
  44     _three: Field
  45 }
  46
  47 struct HasDropImpl {
  48     _one: Field,
  49     _two: Field,
  50     _three: Field
  51 }
  52
  53 #[unsafe_destructor] // because HasDropImpl isn't Send
  54 impl Drop for HasDropImpl {
  55     fn drop(&mut self) {
  56         println!("HasDropImpl.drop()");
  57         assert_eq!(self._one.state.get(), 0);
  58         self._one.state.set(1);
  59     }
  60 }
  61
  62 pub fn main() {
  63     let state = Rc::new(Cell::new(1));
  64     let noImpl = NoDropImpl {
  65         _one: Field::new(1, state.clone()),
  66         _two: Field::new(2, state.clone()),
  67         _three: Field::new(3, state.clone())
  68     };
  69     drop(noImpl);
  70     assert_eq!(state.get(), 4);
  71
  72     state.set(0);
  73     let hasImpl = HasDropImpl {
  74         _one: Field::new(1, state.clone()),
  75         _two: Field::new(2, state.clone()),
  76         _three: Field::new(3, state.clone())
  77     };
  78     drop(hasImpl);
  79     assert_eq!(state.get(), 4);
  80 }