Implement Contains for pallet-membership (#6518)

* implement Contains for pallet-membership

* bump version

substrate/bin/node/runtime/src/lib.rs

@@ -98,7 +98,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
 	spec_version: 254,
-	impl_version: 0,
+	impl_version: 1,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 1,
 };

substrate/frame/membership/src/lib.rs

@@ -26,7 +26,7 @@
 use sp_std::prelude::*;
 use frame_support::{
 	decl_module, decl_storage, decl_event, decl_error,
-	traits::{ChangeMembers, InitializeMembers, EnsureOrigin},
+	traits::{ChangeMembers, InitializeMembers, EnsureOrigin, Contains},
 };
 use frame_system::{self as system, ensure_signed};
 
@@ -264,6 +264,16 @@ impl<T: Trait<I>, I: Instance> Module<T, I> {
 	}
 }
 
+impl<T: Trait<I>, I: Instance> Contains<T::AccountId> for Module<T, I> {
+	fn sorted_members() -> Vec<T::AccountId> {
+		Self::members()
+	}
+
+	fn count() -> usize {
+		Members::<T, I>::decode_len().unwrap_or(0)
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;