Use ‘#[module]’ and implement session for Kusama

src/frame/staking.rs

@@ -16,7 +16,10 @@
 
 //! Implements support for the frame_staking module.
 
-use super::system::{System, SystemEventsDecoder as _};
+use super::system::{
+    System,
+    SystemEventsDecoder as _,
+};
 use codec::{
     Decode,
     Encode,
@@ -111,6 +114,7 @@ impl Default for ValidatorPrefs {
 /// The subset of the `frame::Trait` that a client must implement.
 #[module]
 pub trait Staking: System {}
+impl<T: System> Staking for T {}
 
 /// Just a Balance/BlockNumber tuple to encode when a chunk of funds will be unlocked.
 #[derive(PartialEq, Eq, Clone, Encode, Decode)]