Easy PR: Fix warnings from latest nightly (#14195)

* unneeded mut

* remove needless borrows

substrate/client/db/src/parity_db.rs

@@ -54,16 +54,16 @@ pub fn open<H: Clone + AsRef<[u8]>>(
 			];
 
 			for i in compressed {
-				let mut column = &mut config.columns[i as usize];
+				let column = &mut config.columns[i as usize];
 				column.compression = parity_db::CompressionType::Lz4;
 			}
 
-			let mut state_col = &mut config.columns[columns::STATE as usize];
+			let state_col = &mut config.columns[columns::STATE as usize];
 			state_col.ref_counted = true;
 			state_col.preimage = true;
 			state_col.uniform = true;
 
-			let mut tx_col = &mut config.columns[columns::TRANSACTION as usize];
+			let tx_col = &mut config.columns[columns::TRANSACTION as usize];
 			tx_col.ref_counted = true;
 			tx_col.preimage = true;
 			tx_col.uniform = true;

substrate/client/db/src/pinned_blocks_cache.rs

@@ -168,7 +168,7 @@ impl<Block: BlockT> PinnedBlocksCache<Block> {
 	/// Attach body to an existing cache item
 	pub fn insert_body(&mut self, hash: Block::Hash, extrinsics: Option<Vec<Block::Extrinsic>>) {
 		match self.cache.peek_mut(&hash) {
-			Some(mut entry) => {
+			Some(entry) => {
 				entry.body = Some(extrinsics);
 				log::trace!(
 					target: LOG_TARGET,
@@ -192,7 +192,7 @@ impl<Block: BlockT> PinnedBlocksCache<Block> {
 		justifications: Option<Justifications>,
 	) {
 		match self.cache.peek_mut(&hash) {
-			Some(mut entry) => {
+			Some(entry) => {
 				entry.justifications = Some(justifications);
 				log::trace!(
 					target: LOG_TARGET,

substrate/client/network/src/protocol/notifications/handler.rs

@@ -467,7 +467,7 @@ impl ConnectionHandler for NotifsHandler {
 		match event {
 			ConnectionEvent::FullyNegotiatedInbound(inbound) => {
 				let (mut in_substream_open, protocol_index) = inbound.protocol;
-				let mut protocol_info = &mut self.protocols[protocol_index];
+				let protocol_info = &mut self.protocols[protocol_index];
 
 				match protocol_info.state {
 					State::Closed { pending_opening } => {

substrate/client/network/sync/src/state.rs

@@ -150,7 +150,7 @@ where
 				} else {
 					values.key_values
 				};
-				let mut entry = self.state.entry(values.state_root).or_default();
+				let entry = self.state.entry(values.state_root).or_default();
 				if entry.0.len() > 0 && entry.1.len() > 1 {
 					// Already imported child_trie with same root.
 					// Warning this will not work with parallel download.

substrate/client/statement-store/src/lib.rs

@@ -236,7 +236,7 @@ impl Index {
 		let priority = Priority(statement.priority().unwrap_or(0));
 		self.entries.insert(hash, (account, priority, statement.data_len()));
 		self.total_size += statement.data_len();
-		let mut account_info = self.accounts.entry(account).or_default();
+		let account_info = self.accounts.entry(account).or_default();
 		account_info.data_size += statement.data_len();
 		if let Some(channel) = statement.channel() {
 			account_info.channels.insert(channel, ChannelEntry { hash, priority });
@@ -530,7 +530,7 @@ impl Store {
 
 		let mut config = parity_db::Options::with_columns(&path, col::COUNT);
 
-		let mut statement_col = &mut config.columns[col::STATEMENTS as usize];
+		let statement_col = &mut config.columns[col::STATEMENTS as usize];
 		statement_col.ref_counted = false;
 		statement_col.preimage = true;
 		statement_col.uniform = true;