#![feature(generic_associated_types)]
#![feature(type_alias_impl_trait)]

use std::future::Future;

pub trait Service<Cx, Request> {
    type Response;
    type Future<'cx>: Future<Output = Self::Response> + Send + 'cx
    where
        Cx: 'cx,
        Self: 'cx;

    fn call<'cx, 's>(&'s mut self, cx: &'cx mut Cx, req: Request) -> Self::Future<'cx>
    where
        's: 'cx;
}

pub struct Test<S>(S);

impl<Cx, Req, S> Service<Cx, Req> for Test<S>
where
    Req: Send + 'static,
    S: Service<Cx, Req> + Send + 'static,
    Cx: Send + 'static,
{
    type Response = S::Response;

    type Future<'cx> = impl Send + Future<Output = Self::Response> + 'cx
    where
        Cx: 'cx,
        Self: 'cx;

    fn call<'cx, 's>(&'s mut self, cx: &'cx mut Cx, req: Req) -> Self::Future<'cx>
    where
        's: 'cx,
    {
        async move { self.0.call(cx, req).await }
    }
}

fn main() {}