rust/tests/ui/async-await/async-closures/wrong-fn-kind.rs

// edition:2021

// FIXME(async_closures): This needs a better error message!

#![feature(async_closure)]

fn main() {
    fn needs_async_fn(_: impl async Fn()) {}

    let mut x = 1;
    needs_async_fn(async || {
        //~^ ERROR expected a closure that implements the `async Fn` trait, but this closure only implements `async FnMut`
        x += 1;
    });
}