[feature(conservative_impl_trait)] is stable since rust 1.26

examples/hello_world.rs

@@ -1,4 +1,3 @@
-#![feature(conservative_impl_trait)]
 #![feature(try_from)]
 
 extern crate futures;

examples/hello_world_await.rs

@@ -1,4 +1,3 @@
-#![feature(conservative_impl_trait)]
 #![feature(generators)]
 #![feature(proc_macro)]
 #![feature(try_from)]

src/lib.rs

@@ -2,7 +2,7 @@
 
 #![deny(missing_debug_implementations)]
 #![deny(missing_docs)]
-#![feature(conservative_impl_trait, try_from)]
+#![feature(try_from)]
 
 extern crate futures;
 extern crate hyper;