1 #![feature(generators, generator_trait, never_type)]
3 use std::ops::{GeneratorState::{self, *}, Generator};
5 use std::sync::atomic::{AtomicUsize, Ordering};
7 use std::mem::ManuallyDrop;
11 fn finish<T>(mut amt: usize, mut t: T) -> T::Return
12 where T: Generator<Yield = usize>
14 // We are not moving the `t` around until it gets dropped, so this is okay.
15 let mut t = unsafe { Pin::new_unchecked(&mut t) };
17 let state = t.as_mut().resume(());
18 // Test if the generator is valid (according to type invariants).
19 let _ = unsafe { ManuallyDrop::new(ptr::read(t.as_mut().get_unchecked_mut())) };
21 GeneratorState::Yielded(y) => {
24 GeneratorState::Complete(ret) => {
37 finish(1, || yield 1);
70 if { yield 1; false } {
77 // also test a self-referential generator
80 let mut x = Box::new(5);
102 #[allow(unreachable_code)]
103 let _x: (String, !) = (String::new(), { yield 2; return });
107 fn smoke_resume_arg() {
108 fn drain<G: Generator<R, Yield = Y> + Unpin, R, Y>(
110 inout: Vec<(R, GeneratorState<Y, G::Return>)>,
112 Y: Debug + PartialEq,
113 G::Return: Debug + PartialEq,
115 let mut gen = Pin::new(gen);
117 for (input, out) in inout {
118 assert_eq!(gen.as_mut().resume(input), out);
119 // Test if the generator is valid (according to type invariants).
120 let _ = unsafe { ManuallyDrop::new(ptr::read(gen.as_mut().get_unchecked_mut())) };
124 static DROPS: AtomicUsize = AtomicUsize::new(0);
126 #[derive(Debug, PartialEq)]
129 impl Drop for DropMe {
131 DROPS.fetch_add(1, Ordering::SeqCst);
135 fn expect_drops<T>(expected_drops: usize, f: impl FnOnce() -> T) -> T {
136 DROPS.store(0, Ordering::SeqCst);
140 let actual_drops = DROPS.load(Ordering::SeqCst);
141 assert_eq!(actual_drops, expected_drops);
152 vec![(1, Yielded(2)), (-45, Yielded(-44)), (500, Yielded(501)), (0, Complete(-1))],
155 expect_drops(2, || drain(&mut |a| yield a, vec![(DropMe, Yielded(DropMe))]));
159 &mut |a| yield yield a,
160 vec![(DropMe, Yielded(DropMe)), (DropMe, Yielded(DropMe)), (DropMe, Complete(DropMe))],
164 #[allow(unreachable_code)]
165 expect_drops(2, || drain(&mut |a| yield return a, vec![(DropMe, Complete(DropMe))]));
170 if false { yield () } else { a }
172 vec![(DropMe, Complete(DropMe))],
178 #[allow(unused_assignments, unused_variables)]
179 &mut |mut a: DropMe| {
185 (DropMe, Yielded(())),
186 (DropMe, Yielded(())),
187 (DropMe, Yielded(())),
188 (DropMe, Complete(())),