Fix unresolved type span inside async object

[csmoe]

Closes #65180
r? @estebank
cc @nikomatsakis @cramertj

[estebank]

Does this change have a user visible change?

[csmoe]

@estebank
From

error[E0698]: type inside `async` object must be known in this context
  --> src/lib.rs:23:25
   |
23 |     let server = server.serve(hyper::service::make_service_fn(move |_| {
   |                         ^^^^^ cannot infer type for `ME`
   |
note: the type is part of the `async` object because of this `await`
  --> src/lib.rs:34:5
   |
34 |     server.await
   |     ^^^^^^^^^^^^

To:

error[E0698]: type inside `async fn` body must be known in this context
  --> src/lib.rs:15:13
   |
15 |             Ok(hyper::service::service_fn(move |req| {
   |             ^^ cannot infer type for `ME`
   |
note: the type is part of the `async fn` body because of this `await`
  --> src/lib.rs:24:5
   |
24 |     server.await
   |     ^^^^^^^^^^^^

error: aborting due to previous error

but I should figure out a test/ui.

[estebank]

r=me with a test

[nikomatsakis]

Looks good to me, too

[JohnCSimon]

Ping from triage.
@estebank can you please review this PR?
cc: @nikomatsakis @csmoe
Thank you!

[estebank]

@csmoe can you add a ui test exercising this new code?

[csmoe]

@estebank it's a bit complicated, still trying.

[JohnCSimon]

Ping from triage:
@csmoe How's it going with the UI test?
cc: @estebank
Thank you!

[bors]

☔ The latest upstream changes (presumably #66252) made this pull request unmergeable. Please resolve the merge conflicts.

[JohnCSimon]

Ping from triage:
@csmoe Can you please post your status regarding this PR, and address the merge conflicts?
cc: @estebank
Thank you!

[JohnCSimon]

Pinging once again from triage:
@csmoe Can you please post your status regarding this PR, and address the merge conflicts?

Thank you.

[JohnCSimon]

Triage:

@csmoe - unfortunately this PR has sat idle for several weeks, I'm marking this as inactive. Please reopen this PR when you're ready to move forward.
Thank you