error[E0282]: type annotations needed
  --> $DIR/cannot-infer-async.rs:11:20
   |
LL |     let fut = async {
   |         --- consider giving `fut` a type
LL |         make_unit()?;
   |                    ^ cannot infer type

error: aborting due to previous error

For more information about this error, try `rustc --explain E0282`.