rust/tests/ui/async-await/higher-ranked-auto-trait-9.rs
2025-07-15 16:02:26 +00:00

45 lines
1.0 KiB
Rust

// Repro for <https://github.com/rust-lang/rust/issues/87425#issue-952059416>.
//@ edition: 2021
//@ revisions: assumptions no_assumptions
//@[assumptions] compile-flags: -Zhigher-ranked-assumptions
//@[assumptions] check-pass
//@[no_assumptions] known-bug: #110338
use std::any::Any;
use std::fmt;
use std::future::Future;
pub trait Foo {
type Item;
}
impl<F, I> Foo for F
where
Self: FnOnce() -> I,
I: fmt::Debug,
{
type Item = I;
}
async fn foo_item<F: Foo>(_: F) -> F::Item {
unimplemented!()
}
fn main() {
let fut = async {
let callback = || -> Box<dyn Any> { unimplemented!() };
// Using plain fn instead of a closure fixes the error,
// though you obviously can't capture any state...
// fn callback() -> Box<dyn Any> {
// todo!()
// }
foo_item(callback).await;
};
// Removing `+ Send` bound also fixes the error,
// though at the cost of loosing `Send`ability...
let fut: &(dyn Future<Output = ()> + Send) = &fut as _;
}