51 lines
1.4 KiB
Rust
51 lines
1.4 KiB
Rust
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// edition: 2021
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use std::{
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future::Future,
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pin::Pin,
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task::{Context, Poll, Waker},
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};
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pub struct StructAsync<F: Fn() -> Pin<Box<dyn Future<Output = ()>>>> {
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pub callback: F,
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}
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impl<F> Future for StructAsync<F>
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where
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F: Fn() -> Pin<Box<dyn Future<Output = ()>>>,
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{
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type Output = ();
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fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
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Poll::Pending
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}
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}
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async fn callback() {}
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struct Runtime;
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fn waker() -> &'static Waker {
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todo!()
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}
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impl Runtime {
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#[track_caller]
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pub fn block_on<F: Future>(&self, mut future: F) -> F::Output {
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loop {
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unsafe {
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Pin::new_unchecked(&mut future).poll(&mut Context::from_waker(waker()));
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}
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}
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}
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}
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fn main() {
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Runtime.block_on(async {
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StructAsync { callback }.await;
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//~^ ERROR expected `fn() -> impl Future<Output = ()> {callback}` to be a fn item that returns `Pin<Box<(dyn Future<Output = ()> + 'static)>>`, but it returns `impl Future<Output = ()>`
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//~| ERROR expected `fn() -> impl Future<Output = ()> {callback}` to be a fn item that returns `Pin<Box<(dyn Future<Output = ()> + 'static)>>`, but it returns `impl Future<Output = ()>`
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//~| ERROR expected `fn() -> impl Future<Output = ()> {callback}` to be a fn item that returns `Pin<Box<(dyn Future<Output = ()> + 'static)>>`, but it returns `impl Future<Output = ()>`
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});
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}
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