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 | |
LL | |
LL | | }
   | |_- this function should return `Result` or `Option` to accept `?`
   |
   = help: the trait `FromResidual<_>` is not implemented for `()`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.