| //@ edition: 2021 | |
| #![feature(impl_trait_in_assoc_type)] | |
| use core::future::Future; | |
| trait Recur { | |
| type Recur: Future<Output = ()>; | |
| fn recur(self) -> Self::Recur; | |
| } | |
| async fn recur(t: impl Recur) { | |
| t.recur().await; | |
| } | |
| impl Recur for () { | |
| type Recur = impl Future<Output = ()>; | |
| fn recur(self) -> Self::Recur { | |
| async move { recur(self).await; } | |
| //~^ ERROR recursion in an async block requires boxing | |
| } | |
| } | |
| fn main() { | |
| recur(()); | |
| } |