57 lines
1.2 KiB
Rust
57 lines
1.2 KiB
Rust
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#![feature(generators, generator_trait)]
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use std::{
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cell::RefCell,
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sync::Arc,
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pin::Pin,
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ops::{Generator, GeneratorState},
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};
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pub struct Ready<T>(Option<T>);
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impl<T> Generator<()> for Ready<T> {
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type Return = T;
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type Yield = ();
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fn resume(mut self: Pin<&mut Self>, _args: ()) -> GeneratorState<(), T> {
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GeneratorState::Complete(self.0.take().unwrap())
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}
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}
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pub fn make_gen1<T>(t: T) -> Ready<T> {
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Ready(Some(t))
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}
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fn require_send(_: impl Send) {}
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fn make_non_send_generator() -> impl Generator<Return = Arc<RefCell<i32>>> {
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make_gen1(Arc::new(RefCell::new(0)))
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}
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fn test1() {
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let send_gen = || {
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let _non_send_gen = make_non_send_generator();
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yield;
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};
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require_send(send_gen);
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//~^ ERROR future cannot be sent between threads
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}
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pub fn make_gen2<T>(t: T) -> impl Generator<Return = T> {
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|| {
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yield;
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t
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}
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}
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fn make_non_send_generator2() -> impl Generator<Return = Arc<RefCell<i32>>> {
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make_gen2(Arc::new(RefCell::new(0)))
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}
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fn test2() {
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let send_gen = || {
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let _non_send_gen = make_non_send_generator2();
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yield;
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};
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require_send(send_gen);
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//~^ ERROR `std::cell::RefCell<i32>` cannot be shared between threads safely
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}
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fn main() {}
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