   LL|       |// Regression test for <https://github.com/rust-lang/rust/issues/151135>.
   LL|       |
   LL|       |//@ edition: 2021
   LL|       |
   LL|       |//@ aux-build: executor.rs
   LL|       |extern crate executor;
   LL|       |
   LL|       |use std::sync::atomic::{AtomicUsize, Ordering};
   LL|       |
   LL|       |static STEPS: AtomicUsize = AtomicUsize::new(0);
   LL|       |
   LL|      1|async fn call_once(f: impl AsyncFnOnce()) {
   LL|      1|    f().await;
   LL|      1|}
   LL|       |
   LL|      1|pub fn main() {
   LL|      1|    let async_closure = async || {
   LL|      1|        STEPS.fetch_add(1, Ordering::SeqCst);
   LL|      1|        STEPS.fetch_add(1, Ordering::SeqCst);
   LL|      1|    };
  ------------------
  | Unexecuted instantiation: async_closure2::main::{closure#0}::{closure#0}::<_>
  ------------------
  | async_closure2::main::{closure#0}:
  |   LL|      1|    let async_closure = async || {
  |   LL|      1|        STEPS.fetch_add(1, Ordering::SeqCst);
  |   LL|      1|        STEPS.fetch_add(1, Ordering::SeqCst);
  |   LL|      1|    };
  ------------------
   LL|      1|    executor::block_on(call_once(async_closure));
   LL|      1|    assert_eq!(STEPS.load(Ordering::SeqCst), 2);
   LL|      1|}