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