error[E0277]: `()` is not a future --> $DIR/unnecessary-await.rs:9:10 | LL | boo().await; | -----^^^^^^ `()` is not a future | | | this call returns `()` | = help: the trait `Future` is not implemented for `()` = note: () must be a future or must implement `IntoFuture` to be awaited = note: required for `()` to implement `IntoFuture` help: remove the `.await` | LL - boo().await; LL + boo(); | help: alternatively, consider making `fn boo` asynchronous | LL | async fn boo() {} | +++++ error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.