// check-pass // edition: 2021 #![feature(async_fn_in_trait)] #![feature(return_position_impl_trait_in_trait, lint_reasons)] #![allow(incomplete_features)] use std::future::Future; use std::pin::Pin; use std::task::Poll; pub trait MyTrait { #[allow(async_fn_in_trait)] async fn foo(&self) -> i32; } #[derive(Clone)] struct MyFuture(i32); impl Future for MyFuture { type Output = i32; fn poll( self: Pin<&mut Self>, _: &mut std::task::Context<'_>, ) -> Poll<::Output> { Poll::Ready(self.0) } } impl MyTrait for i32 { #[expect(refining_impl_trait)] fn foo(&self) -> impl Future + Clone { MyFuture(*self) } } fn main() {}