Does Server have to be 'static?

[djc]

I'm wondering if it could be okay for Server to grow a lifetime parameter, reflecting the inner MakeServiceRef. I can't see why this is not allowed:

pub async fn run<'a, A>(addr: &'a SocketAddr, app: &'a A) -> Result<(), hyper::Error>
    where
        A: Application<RequestBody = Body, ResponseBody = Body> + Send + Sync,
    {
        Server::bind(addr)
            .serve(make_service_fn(move |_| {
                async {
                    Ok::<_, Infallible>(service_fn(move |req| {
                        let cx = Context::new(app, req);
                        A::handle(cx).map(Ok::<_, Infallible>)
                    }))
                }
            }))
            .await
    }

errors with:

error: cannot infer an appropriate lifetime
  --> mendes/src/lib.rs:37:51
   |
37 |     pub async fn run<'a, A>(addr: &'a SocketAddr, app: &'a A) -> Result<(), hyper::Error>
   |                                                   ^^^ ...but this borrow...
...
42 |             .serve(make_service_fn(move |_| {
   |              ----- this return type evaluates to the `'static` lifetime...
   |
note: ...can't outlive the lifetime `'a` as defined on the function body at 37:22
  --> mendes/src/lib.rs:37:22
   |
37 |     pub async fn run<'a, A>(addr: &'a SocketAddr, app: &'a A) -> Result<(), hyper::Error>
   |                      ^^

[LucioFranco]

I think we are limited by GAT here since tower's futures are required to be static.

[seanmonstar]

Maybe it can work if the executor you passed used scoped tasks somehow? The future from the MakeService is spawned on the executor.