error: future cannot be sent between threads safely
  --> $DIR/issue-67893.rs:9:7
   |
LL |     g(issue_67893::run())
   |       ^^^^^^^^^^^^^^^^^^ future is not `Send`
   |
   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
   = note: consider using `std::sync::Arc<MutexGuard<'_, ()>>`; for more information visit <https://doc.rust-lang.org/book/ch16-03-shared-state.html>
note: future is not `Send` as this value is used across an await
  --> $DIR/auxiliary/issue_67893.rs:12:27
   |
LL |     f(*x.lock().unwrap()).await;
   |        -----------------  ^^^^^- `x.lock().unwrap()` is later dropped here
   |        |                  |
   |        |                  await occurs here, with `x.lock().unwrap()` maybe used later
   |        has type `MutexGuard<'_, ()>` which is not `Send`
note: required by a bound in `g`
  --> $DIR/issue-67893.rs:6:14
   |
LL | fn g(_: impl Send) {}
   |              ^^^^ required by this bound in `g`

error: aborting due to previous error