Fix minor clippy lints in grandpa (#5988)

* grandpa: fix clippy lints about identity conversions

* grandpa: fix clippy lints about unwrap_or_default

* grandpa: fix clippy lints about explicit return

* grandpa: fix clippy lints about unnecessary intermediary

* grandpa: fix clippy lints about to_string

* grandpa: fix clippy lints about unused imports

* grandpa: fix clippy lints about increments

* grandpa: fix clippy lints about unnecessary matches

* grandpa: fix clippy lints about struct arguments

* Fix clippy::redundant_clone

* Fix clippy::clone_on_copy

* Fix clippy::or_fun_call

* Fix clippy::identity_conversion

substrate/client/finality-grandpa/src/communication/gossip.rs

@@ -887,7 +887,7 @@ impl<Block: BlockT> Inner<Block> {
 				// any catch up requests until we import this one (either with a
 				// success or failure).
 				self.pending_catch_up = PendingCatchUp::Processing {
-					instant: instant.clone(),
+					instant: *instant,
 				};
 
 				// always discard catch up messages, they're point-to-point
@@ -1281,7 +1281,7 @@ impl<Block: BlockT> GossipValidator<Block> {
 			inner: parking_lot::RwLock::new(Inner::new(config)),
 			set_state,
 			report_sender: tx,
-			metrics: metrics,
+			metrics,
 		};
 
 		(val, rx)

substrate/client/finality-grandpa/src/communication/mod.rs

@@ -236,16 +236,14 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 
 		let (neighbor_packet_worker, neighbor_packet_sender) = periodic::NeighborPacketWorker::new();
 
-		let bridge = NetworkBridge {
+		NetworkBridge {
 			service,
 			gossip_engine,
 			validator,
 			neighbor_sender: neighbor_packet_sender,
 			neighbor_packet_worker: Arc::new(Mutex::new(neighbor_packet_worker)),
 			gossip_validator_report_stream: Arc::new(Mutex::new(report_stream)),
-		};
-
-		bridge
+		}
 	}
 
 	/// Note the beginning of a new round to the `GossipValidator`.
@@ -304,7 +302,7 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 				match decoded {
 					Err(ref e) => {
 						debug!(target: "afg", "Skipping malformed message {:?}: {}", notification, e);
-						return future::ready(None);
+						future::ready(None)
 					}
 					Ok(GossipMessage::Vote(msg)) => {
 						// check signature.
@@ -343,7 +341,7 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 					}
 					_ => {
 						debug!(target: "afg", "Skipping unknown message type");
-						return future::ready(None);
+						future::ready(None)
 					}
 				}
 			});
@@ -666,7 +664,7 @@ impl<Block: BlockT> Sink<Message<Block>> for OutgoingMessages<Block>
 
 		// when locals exist, sign messages on import
 		if let Some((ref pair, _)) = self.locals {
-			let target_hash = msg.target().0.clone();
+			let target_hash = *(msg.target().0);
 			let signed = sp_finality_grandpa::sign_message(
 				msg,
 				pair,

substrate/client/finality-grandpa/src/communication/periodic.rs

@@ -86,7 +86,7 @@ impl <B: BlockT> Stream for NeighborPacketWorker<B> {
 				this.delay.reset(REBROADCAST_AFTER);
 				this.last = Some((to.clone(), packet.clone()));
 
-				return Poll::Ready(Some((to, GossipMessage::<B>::from(packet.clone()))));
+				return Poll::Ready(Some((to, GossipMessage::<B>::from(packet))));
 			}
 			// Don't return yet, maybe the timer fired.
 			Poll::Pending => {},
@@ -108,6 +108,6 @@ impl <B: BlockT> Stream for NeighborPacketWorker<B> {
 			return Poll::Ready(Some((to.clone(), GossipMessage::<B>::from(packet.clone()))));
 		}
 
-		return Poll::Pending;
+		Poll::Pending
 	}
 }