cargo.out

@@ -1,20 +1,14 @@
-   Compiling futuretest v0.1.0 (file:///mnt/d/GIT/futuretest)
+   Compiling futuretest v0.1.0 (file:///mnt/c/Users/Mahmoud/git/futuretest)
-error[E0308]: match arms have incompatible types
+error[E0277]: the trait bound `(): futures::Future` is not satisfied
-  --> src/main.rs:21:13
+  --> src/main.rs:17:1
    |
-21 | /             match err {
+17 | / fn test() -> MapErr<(), ()> {
-22 | |                 ErrorCode::Case1 => case1(),
+18 | |     future::ok(())
-23 | |                 ErrorCode::Case2 => case2(),
+19 | |         .map_err(|String| ())
-24 | |             }
+20 | | }
-   | |_____________^ expected anonymized type, found a different anonymized type
+   | |_^ the trait `futures::Future` is not implemented for `()`
    |
-   = note: expected type `impl futures::Future` (anonymized type)
+   = note: required by `futures::MapErr`
-              found type `impl futures::Future` (anonymized type)
-note: match arm with an incompatible type
-  --> src/main.rs:23:37
-   |
-23 |                 ErrorCode::Case2 => case2(),
-   |                                     ^^^^^^^
 
 error: aborting due to previous error
 

src/main.rs

@@ -6,37 +6,15 @@ use futures::future::{self};
 use futures::future::*;
 use tokio_core::reactor::Core;
 
-enum ErrorCode
-{
-    Case1,
-    Case2,
-}
-
 fn main() {
     let mut core = Core::new().expect("Failed to initialize tokio_core reactor!");
 
-    let f = async_entry_point()
+    let f = test();
-        .or_else(move |err| {
-            //the problem is that the three matches below resolve to different anonymized types
-            match err {
-                ErrorCode::Case1 => case1(),
-                ErrorCode::Case2 => case2(),
-            }
-        })
-    ;
 
-    core.run(f);
+    core.run(f).unwrap();
-}
-
-fn async_entry_point() -> impl Future<Item=(), Error=ErrorCode> {
-    future::ok(())
 }
 
-fn case1() -> impl Future<Item=(), Error=ErrorCode> {
+fn test() -> MapErr<(), ()> {
     future::ok(())
+        .map_err(|String| ())
 }
-
-fn case2() -> impl Future<Item=(), Error=ErrorCode> {
-    future::ok(())
-}
-