Corrected error output

Makefile

@@ -9,7 +9,7 @@ bench:
 	@$(CARGO) bench
 
 build:
-	@env TERM=xterm-256color $(CARGO) build --color=always 2>&1; $(CARGO) build 2> cargo.out 1>/dev/null
+	@env TERM=xterm-256color $(CARGO) build --color=always 2>&1
 
 check: build test
 

cargo.out

@@ -1,14 +1,13 @@
-   Compiling futuretest v0.1.0 (file:///mnt/c/Users/Mahmoud/git/futuretest)
-error[E0277]: the trait bound `(): futures::Future` is not satisfied
-  --> src/main.rs:17:1
+   Compiling futuretest v0.1.0 (file:///mnt/d/GIT/futuretest)
+error[E0271]: type mismatch resolving `<futures::FutureResult<std::result::Result<(), _>, ()> as futures::Future>::Item == ()`
+  --> src/main.rs:17:23
    |
-17 | / fn test() -> MapErr<(), ()> {
-18 | |     future::ok(())
-19 | |         .map_err(|String| ())
-20 | | }
-   | |_^ the trait `futures::Future` is not implemented for `()`
+17 | fn create_future() -> impl Future<Item=(), Error=()> {
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected enum `std::result::Result`, found ()
    |
-   = note: required by `futures::MapErr`
+   = note: expected type `std::result::Result<(), _>`
+              found type `()`
+   = note: the return type of a function must have a statically known size
 
 error: aborting due to previous error
 

src/main.rs

@@ -9,12 +9,11 @@ use tokio_core::reactor::Core;
 fn main() {
     let mut core = Core::new().expect("Failed to initialize tokio_core reactor!");
 
-    let f = test();
+    let f = create_future();
 
     core.run(f).unwrap();
 }
 
-fn test() -> MapErr<(), ()> {
-    future::ok(())
-        .map_err(|String| ())
+fn create_future() -> impl Future<Item=(), Error=()> {
+    return future::ok(Ok(()));
 }