| error[E0277]: the `?` operator can only be applied to values that implement `Try` | 
 |   --> $DIR/issue-84841.rs:9:5 | 
 |    | | 
 | LL |     test()?; | 
 |    |     ^^^^^^^ the `?` operator cannot be applied to type `impl Future<Output = ()>` | 
 |    | | 
 |    = help: the trait `Try` is not implemented for `impl Future<Output = ()>` | 
 |  | 
 | error[E0277]: the `?` operator can only be used in an async function that returns `Result` or `Option` (or another type that implements `FromResidual`) | 
 |   --> $DIR/issue-84841.rs:9:11 | 
 |    | | 
 | LL |   async fn foo() { | 
 |    |  ________________- | 
 | LL | |     // Adding an .await here avoids the ICE | 
 | LL | |     test()?; | 
 |    | |           ^ cannot use the `?` operator in an async function that returns `()` | 
 | ...  | | 
 | LL | | } | 
 |    | |_- this function should return `Result` or `Option` to accept `?` | 
 |  | 
 | error: aborting due to 2 previous errors | 
 |  | 
 | For more information about this error, try `rustc --explain E0277`. |