src/test/ui/run-pass/generator/conditional-drop.rs

   1 // Copyright 2017 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 // run-pass
  12
  13 #![feature(generators, generator_trait)]
  14
  15 use std::ops::Generator;
  16 use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
  17
  18 static A: AtomicUsize = ATOMIC_USIZE_INIT;
  19
  20 struct B;
  21
  22 impl Drop for B {
  23     fn drop(&mut self) {
  24         A.fetch_add(1, Ordering::SeqCst);
  25     }
  26 }
  27
  28
  29 fn test() -> bool { true }
  30 fn test2() -> bool { false }
  31
  32 fn main() {
  33     t1();
  34     t2();
  35 }
  36
  37 fn t1() {
  38     let mut a = || {
  39         let b = B;
  40         if test() {
  41             drop(b);
  42         }
  43         yield;
  44     };
  45
  46     let n = A.load(Ordering::SeqCst);
  47     unsafe { a.resume() };
  48     assert_eq!(A.load(Ordering::SeqCst), n + 1);
  49     unsafe { a.resume() };
  50     assert_eq!(A.load(Ordering::SeqCst), n + 1);
  51 }
  52
  53 fn t2() {
  54     let mut a = || {
  55         let b = B;
  56         if test2() {
  57             drop(b);
  58         }
  59         yield;
  60     };
  61
  62     let n = A.load(Ordering::SeqCst);
  63     unsafe { a.resume() };
  64     assert_eq!(A.load(Ordering::SeqCst), n);
  65     unsafe { a.resume() };
  66     assert_eq!(A.load(Ordering::SeqCst), n + 1);
  67 }