src/test/ui/async-await/issues/issue-59001.rs

// build-pass (FIXME(62277): could be check-pass?)
// edition:2018

use std::future::Future;

async fn enter<'a, F, R>(mut callback: F)
where
    F: FnMut(&'a mut i32) -> R,
    R: Future<Output = ()> + 'a,
{
    unimplemented!()
}

fn main() {}