Bump clippy, fix warnings (#1939)

* Bumping clippy

* Fixing warnings

util/src/journaldb/overlayrecentdb.rs

@@ -218,7 +218,7 @@ impl JournalDB for OverlayRecentDB {
 		let journal_overlay = self.journal_overlay.read();
 		let key = to_short_key(key);
 		journal_overlay.backing_overlay.get(&key).map(|v| v.to_vec())
-		.or_else(|| journal_overlay.pending_overlay.get(&key).map(|v| v.clone()))
+		.or_else(|| journal_overlay.pending_overlay.get(&key).cloned())
 		.or_else(|| self.backing.get_by_prefix(self.column, &key[0..DB_PREFIX_LEN]).map(|b| b.to_vec()))
 	}
 
@@ -365,7 +365,7 @@ impl HashDB for OverlayRecentDB {
 					let journal_overlay = self.journal_overlay.read();
 					let key = to_short_key(key);
 					journal_overlay.backing_overlay.get(&key).map(|v| v.to_vec())
-						.or_else(|| journal_overlay.pending_overlay.get(&key).map(|v| v.clone()))
+						.or_else(|| journal_overlay.pending_overlay.get(&key).cloned())
 				};
 				match v {
 					Some(x) => {

util/src/lib.rs

@@ -27,6 +27,8 @@
 #![cfg_attr(feature="dev", allow(match_same_arms))]
 // Keeps consistency (all lines with `.clone()`).
 #![cfg_attr(feature="dev", allow(clone_on_copy))]
+// Some false positives when doing pattern matching.
+#![cfg_attr(feature="dev", allow(needless_borrow))]
 // TODO [todr] a lot of warnings to be fixed
 #![cfg_attr(feature="dev", allow(assign_op_pattern))]
 

util/src/trie/node.rs

@@ -73,7 +73,7 @@ impl<'a> Node<'a> {
 				stream.append(value);
 				stream.out()
 			},
-			Node::Extension(ref slice, ref raw_rlp) => {
+			Node::Extension(ref slice, raw_rlp) => {
 				let mut stream = RlpStream::new_list(2);
 				stream.append(&slice.encoded(false));
 				stream.append_raw(raw_rlp, 1);
@@ -108,7 +108,7 @@ impl<'a> Node<'a> {
 				stream.append(&slice.encoded(true));
 				stream.append(value);
 			},
-			Node::Extension(ref slice, ref raw_rlp) => {
+			Node::Extension(ref slice, raw_rlp) => {
 				stream.begin_list(2);
 				stream.append(&slice.encoded(false));
 				stream.append_raw(raw_rlp, 1);

util/src/trie/triedb.rs

@@ -153,7 +153,7 @@ impl<'db> TrieDB<'db> {
 	fn fmt_all(&self, node: Node, f: &mut fmt::Formatter, deepness: usize) -> fmt::Result {
 		match node {
 			Node::Leaf(slice, value) => try!(writeln!(f, "'{:?}: {:?}.", slice, value.pretty())),
-			Node::Extension(ref slice, ref item) => {
+			Node::Extension(ref slice, item) => {
 				try!(write!(f, "'{:?} ", slice));
 				if let Ok(node) = self.get_node(item) {
 					try!(self.fmt_all(node, f, deepness));
@@ -203,8 +203,8 @@ impl<'db> TrieDB<'db> {
 		where 'db: 'key
 	{
 		match Node::decoded(node) {
-			Node::Leaf(ref slice, ref value) if key == slice => Ok(Some(value)),
-			Node::Extension(ref slice, ref item) if key.starts_with(slice) => {
+			Node::Leaf(ref slice, value) if key == slice => Ok(Some(value)),
+			Node::Extension(ref slice, item) if key.starts_with(slice) => {
 				let data = try!(self.get_raw_or_lookup(item));
 				self.get_from_node(data, &key.mid(slice.len()))
 			},

util/src/trie/triedbmut.rs

@@ -419,8 +419,8 @@ impl<'a> TrieDBMut<'a> {
 		where 'x: 'key
 	{
 		match RlpNode::decoded(node) {
-			RlpNode::Leaf(ref slice, ref value) if &key == slice => Ok(Some(value)),
-			RlpNode::Extension(ref slice, ref item) if key.starts_with(slice) => {
+			RlpNode::Leaf(ref slice, value) if &key == slice => Ok(Some(value)),
+			RlpNode::Extension(ref slice, item) if key.starts_with(slice) => {
 				self.get_from_db_node(try!(self.get_raw_or_lookup(item)), key.mid(slice.len()))
 			},
 			RlpNode::Branch(ref nodes, value) => match key.is_empty() {