error[E0728]: `await` is only allowed inside `async` functions and blocks
  --> $DIR/issue-51751.rs:11:20
   |
LL | async fn inc(limit: i64) -> i64 {
   | ------------------------------- this function is not `async`
...
LL |     let finished = result.await;
   |                    ^^^^^^^^^^^^ only allowed inside `async` functions and blocks

error: aborting due to previous error