Add a test, and change umbrella impl...

...to be for Deref<Target=S> where S: Service instead of Deref<Target=Service>.

tarpc/src/macros.rs

@@ -198,8 +198,9 @@ macro_rules! rpc {
                     )*
                 }
 
-                impl<P> Service for P
-                    where P: Send + Sync + ::std::ops::Deref<Target=Service>
+                impl<P, S> Service for P
+                    where P: Send + Sync + ::std::ops::Deref<Target=S>,
+                          S: Service
                 {
                     $(
                         $(#[$attr])*
@@ -313,6 +314,15 @@ mod test {
         }
     }
 
+    #[test]
+    fn serve_arc_server() {
+        serve("localhost:0",
+              ::std::sync::Arc::new(Server),
+              None)
+            .unwrap()
+            .shutdown();
+    }
+
     #[test]
     fn simple_test() {
         println!("Starting");