Remove compilation warnings. (#2835)

* Remove compilation warnings.

* Allow unused only not in tests.

* Remove unnecessary mut.

* Make CI happy.

* Revert "Make CI happy."

This reverts commit abb865fe4b9fe9af1ae3ec801da9d4305ea35765.

substrate/core/network/src/test/mod.rs

@@ -282,6 +282,10 @@ pub struct Peer<D, S: NetworkSpecialization<Block>> {
 	peer_id: PeerId,
 	client: PeersClient,
 	net_proto_channel: ProtocolChannel<S>,
+	/// This field is used only in test code, but maintaining different
+	/// instantiation paths or field names is too much hassle, hence
+	/// we allow it to be unused.
+	#[cfg_attr(not(test), allow(unused))]
 	protocol_status: Arc<RwLock<ProtocolStatus<Block>>>,
 	import_queue: Box<BasicQueue<Block>>,
 	pub data: D,
@@ -471,6 +475,7 @@ impl<D, S: NetworkSpecialization<Block>> Peer<D, S> {
 		self.net_proto_channel.send_from_client(ProtocolMsg::BlockImported(info.chain.best_hash, header));
 	}
 
+	#[cfg(test)]
 	fn on_block_imported(
 		&self,
 		hash: <Block as BlockT>::Hash,
@@ -492,6 +497,7 @@ impl<D, S: NetworkSpecialization<Block>> Peer<D, S> {
 	}
 
 	/// Get protocol status.
+	#[cfg(test)]
 	fn protocol_status(&self) -> ProtocolStatus<Block> {
 		self.protocol_status.read().clone()
 	}
@@ -608,6 +614,7 @@ impl<D, S: NetworkSpecialization<Block>> Peer<D, S> {
 	}
 
 	/// Announce a block to peers.
+	#[cfg(test)]
 	fn announce_block(&self, block: Hash) {
 		self.net_proto_channel.send_from_client(ProtocolMsg::AnnounceBlock(block));
 	}