error[E0477]: the type `&mut ()` does not fulfill the required lifetime
  --> $DIR/issue-90014.rs:14:5
   |
LL |     type Fut<'a> = impl Future<Output = ()>;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: type must outlive the lifetime `'a` as defined here
  --> $DIR/issue-90014.rs:14:14
   |
LL |     type Fut<'a> = impl Future<Output = ()>;
   |              ^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0477`.
