mirror of https://github.com/rust-lang/rust
81 lines
1.7 KiB
Rust
81 lines
1.7 KiB
Rust
//@ check-pass
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//@ compile-flags: --edition=2021 --crate-type=lib
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use std::{
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future::Future,
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marker::PhantomData,
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pin::Pin,
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task::{Context, Poll},
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};
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mod object {
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use super::*;
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pub trait Object<'a> {
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type Error;
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type Future: Future<Output = Self>;
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fn create() -> Self::Future;
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}
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impl<'a> Object<'a> for u8 {
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type Error = ();
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type Future = Pin<Box<dyn Future<Output = Self>>>;
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fn create() -> Self::Future {
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unimplemented!()
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}
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}
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impl<'a, E, A: Object<'a, Error = E>> Object<'a> for (A,) {
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type Error = ();
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type Future = CustomFut<'a, E, A>;
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fn create() -> Self::Future {
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unimplemented!()
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}
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}
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pub struct CustomFut<'f, E, A: Object<'f, Error = E>> {
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ph: PhantomData<(A::Future,)>,
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}
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impl<'f, E, A: Object<'f, Error = E>> Future for CustomFut<'f, E, A> {
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type Output = (A,);
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fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> {
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unimplemented!()
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}
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}
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}
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mod async_fn {
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use super::*;
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pub trait AsyncFn {
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type Future: Future<Output = ()>;
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fn call(&self) -> Self::Future;
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}
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impl<F, Fut> AsyncFn for F
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where
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F: Fn() -> Fut,
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Fut: Future<Output = ()>,
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{
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type Future = Fut;
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fn call(&self) -> Self::Future {
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(self)()
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}
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}
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}
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pub async fn test() {
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use self::{async_fn::AsyncFn, object::Object};
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async fn create<T: Object<'static>>() {
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T::create().await;
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}
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async fn call_async_fn(inner: impl AsyncFn) {
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inner.call().await;
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}
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call_async_fn(create::<(u8,)>).await;
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}
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