src/test/ui/generator/resume-live-across-yield.rs

   1 // run-pass
   2
   3 #![feature(generators, generator_trait)]
   4
   5 use std::ops::{Generator, GeneratorState};
   6 use std::pin::Pin;
   7 use std::sync::atomic::{AtomicUsize, Ordering};
   8
   9 static DROP: AtomicUsize = AtomicUsize::new(0);
  10
  11 #[derive(PartialEq, Eq, Debug)]
  12 struct Dropper(String);
  13
  14 impl Drop for Dropper {
  15     fn drop(&mut self) {
  16         DROP.fetch_add(1, Ordering::SeqCst);
  17     }
  18 }
  19
  20 fn main() {
  21     let mut g = |mut _d| {
  22         _d = yield;
  23         _d
  24     };
  25
  26     let mut g = Pin::new(&mut g);
  27
  28     assert_eq!(
  29         g.as_mut().resume(Dropper(String::from("Hello world!"))),
  30         GeneratorState::Yielded(())
  31     );
  32     assert_eq!(DROP.load(Ordering::Acquire), 0);
  33     match g.as_mut().resume(Dropper(String::from("Number Two"))) {
  34         GeneratorState::Complete(dropper) => {
  35             assert_eq!(DROP.load(Ordering::Acquire), 1);
  36             assert_eq!(dropper.0, "Number Two");
  37             drop(dropper);
  38             assert_eq!(DROP.load(Ordering::Acquire), 2);
  39         }
  40         _ => unreachable!(),
  41     }
  42
  43     drop(g);
  44     assert_eq!(DROP.load(Ordering::Acquire), 2);
  45 }