diff --git a/README.md b/README.md
index 216ac8091..48172bb60 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,5 @@
 # ethcore
+
+
+# Running clippy
+
diff --git a/util/src/bytes.rs b/util/src/bytes.rs
index 479a91df0..a954d8acd 100644
--- a/util/src/bytes.rs
+++ b/util/src/bytes.rs
@@ -99,18 +99,18 @@ impl<'a> Deref for BytesRef<'a> {
 	type Target = [u8];
 
 	fn deref(&self) -> &[u8] {
-		match self {
-			&BytesRef::Flexible(ref bytes) => bytes,
-			&BytesRef::Fixed(ref bytes) => bytes
+		match *self {
+			BytesRef::Flexible(ref bytes) => bytes,
+			BytesRef::Fixed(ref bytes) => bytes
 		}
 	}
 }
 
 impl <'a> DerefMut for BytesRef<'a> {
 	fn deref_mut(&mut self) -> &mut [u8] {
-		match self {
-			&mut BytesRef::Flexible(ref mut bytes) => bytes,
-			&mut BytesRef::Fixed(ref mut bytes) => bytes
+		match *self {
+			BytesRef::Flexible(ref mut bytes) => bytes,
+			BytesRef::Fixed(ref mut bytes) => bytes
 		}
 	}
 }
@@ -283,7 +283,7 @@ pub trait FromBytes: Sized {
 
 impl FromBytes for String {
 	fn from_bytes(bytes: &[u8]) -> FromBytesResult<String> {
-		Ok(::std::str::from_utf8(bytes).unwrap().to_string())
+		Ok(::std::str::from_utf8(bytes).unwrap().to_owned())
 	}
 }
 
diff --git a/util/src/chainfilter.rs b/util/src/chainfilter.rs
index e1804c191..386664837 100644
--- a/util/src/chainfilter.rs
+++ b/util/src/chainfilter.rs
@@ -321,10 +321,9 @@ impl<'a, D> ChainFilter<'a, D> where D: FilterDataSource
 			let offset = level_size * index;
 
 			// go doooown!
-			match self.blocks(bloom, from_block, to_block, max_level, offset) {
-				Some(blocks) => result.extend(blocks),
-				None => ()
-			};
+			if let Some(blocks) = self.blocks(bloom, from_block, to_block, max_level, offset) {
+				result.extend(blocks);
+			}
 		}
 
 		result
diff --git a/util/src/hash.rs b/util/src/hash.rs
index 17057ef07..793924f8f 100644
--- a/util/src/hash.rs
+++ b/util/src/hash.rs
@@ -193,11 +193,11 @@ macro_rules! impl_hash {
 
 		impl FromJson for $from {
 			fn from_json(json: &Json) -> Self {
-				match json {
-					&Json::String(ref s) => {
+				match *json {
+					Json::String(ref s) => {
 						match s.len() % 2 {
 							0 => FromStr::from_str(clean_0x(s)).unwrap(),
-							_ => FromStr::from_str(&("0".to_string() + &(clean_0x(s).to_string()))[..]).unwrap()
+							_ => FromStr::from_str(&("0".to_owned() + &(clean_0x(s).to_owned()))[..]).unwrap()
 						}
 					},
 					_ => Default::default(),
@@ -207,7 +207,7 @@ macro_rules! impl_hash {
 
 		impl fmt::Debug for $from {
 			fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-				for i in self.0.iter() {
+				for i in &self.0[..] {
 					try!(write!(f, "{:02x}", i));
 				}
 				Ok(())
@@ -215,11 +215,11 @@ macro_rules! impl_hash {
 		}
 		impl fmt::Display for $from {
 			fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-				for i in self.0[0..2].iter() {
+				for i in &self.0[0..2] {
 					try!(write!(f, "{:02x}", i));
 				}
 				try!(write!(f, "…"));
-				for i in self.0[$size - 4..$size].iter() {
+				for i in &self.0[$size - 4..$size] {
 					try!(write!(f, "{:02x}", i));
 				}
 				Ok(())
@@ -277,36 +277,36 @@ macro_rules! impl_hash {
 		impl Index<usize> for $from {
 			type Output = u8;
 
-			fn index<'a>(&'a self, index: usize) -> &'a u8 {
+			fn index(&self, index: usize) -> &u8 {
 				&self.0[index]
 			}
 		}
 		impl IndexMut<usize> for $from {
-			fn index_mut<'a>(&'a mut self, index: usize) -> &'a mut u8 {
+			fn index_mut(&mut self, index: usize) -> &mut u8 {
 				&mut self.0[index]
 			}
 		}
 		impl Index<ops::Range<usize>> for $from {
 			type Output = [u8];
 
-			fn index<'a>(&'a self, index: ops::Range<usize>) -> &'a [u8] {
+			fn index(&self, index: ops::Range<usize>) -> &[u8] {
 				&self.0[index]
 			}
 		}
 		impl IndexMut<ops::Range<usize>> for $from {
-			fn index_mut<'a>(&'a mut self, index: ops::Range<usize>) -> &'a mut [u8] {
+			fn index_mut(&mut self, index: ops::Range<usize>) -> &mut [u8] {
 				&mut self.0[index]
 			}
 		}
 		impl Index<ops::RangeFull> for $from {
 			type Output = [u8];
 
-			fn index<'a>(&'a self, _index: ops::RangeFull) -> &'a [u8] {
+			fn index(&self, _index: ops::RangeFull) -> &[u8] {
 				&self.0
 			}
 		}
 		impl IndexMut<ops::RangeFull> for $from {
-			fn index_mut<'a>(&'a mut self, _index: ops::RangeFull) -> &'a mut [u8] {
+			fn index_mut(&mut self, _index: ops::RangeFull) -> &mut [u8] {
 				&mut self.0
 			}
 		}
@@ -424,7 +424,7 @@ macro_rules! impl_hash {
 			fn from(s: &'_ str) -> $from {
 				use std::str::FromStr;
 				if s.len() % 2 == 1 {
-					$from::from_str(&("0".to_string() + &(clean_0x(s).to_string()))[..]).unwrap_or($from::new())
+					$from::from_str(&("0".to_owned() + &(clean_0x(s).to_owned()))[..]).unwrap_or($from::new())
 				} else {
 					$from::from_str(clean_0x(s)).unwrap_or($from::new())
 				}
diff --git a/util/src/io/service.rs b/util/src/io/service.rs
index 4a96d19a7..537f26b8f 100644
--- a/util/src/io/service.rs
+++ b/util/src/io/service.rs
@@ -93,17 +93,17 @@ impl<Message> Handler for IoManager<Message> where Message: Send + 'static {
 
 	fn ready(&mut self, event_loop: &mut EventLoop<Self>, token: Token, events: EventSet) {
 		if events.is_hup() {
-			for h in self.handlers.iter_mut() {
+			for h in &mut self.handlers {
 				h.stream_hup(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
 			}
 		}
 		else if events.is_readable() {
-			for h in self.handlers.iter_mut() {
+			for h in &mut self.handlers {
 				h.stream_readable(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
 			}
 		}
 		else if events.is_writable() {
-			for h in self.handlers.iter_mut() {
+			for h in &mut self.handlers {
 				h.stream_writable(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
 			}
 		}
@@ -116,13 +116,13 @@ impl<Message> Handler for IoManager<Message> where Message: Send + 'static {
 					let timer = self.timers.get_mut(token).expect("Unknown user timer token");
 					timer.delay
 				};
-				for h in self.handlers.iter_mut() {
+				for h in &mut self.handlers {
 					h.timeout(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
 				}
 				event_loop.timeout_ms(token, delay).expect("Error re-registering user timer");
 			}
 			_ => { // Just pass the event down. IoHandler is supposed to re-register it if required.
-				for h in self.handlers.iter_mut() {
+				for h in &mut self.handlers {
 					h.timeout(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
 				}
 			}
@@ -140,7 +140,7 @@ impl<Message> Handler for IoManager<Message> where Message: Send + 'static {
 				self.handlers.last_mut().unwrap().initialize(&mut IoContext::new(event_loop, &mut self.timers));
 			},
 			IoMessage::UserMessage(ref mut data) => {
-				for h in self.handlers.iter_mut() {
+				for h in &mut self.handlers {
 					h.message(&mut IoContext::new(event_loop, &mut self.timers), data);
 				}
 			}
diff --git a/util/src/json_aid.rs b/util/src/json_aid.rs
index 79a71cac6..417017c31 100644
--- a/util/src/json_aid.rs
+++ b/util/src/json_aid.rs
@@ -18,10 +18,10 @@ fn u256_from_str(s: &str) -> U256 {
 
 impl FromJson for Bytes {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::String(ref s) => match s.len() % 2 {
+		match *json {
+			Json::String(ref s) => match s.len() % 2 {
 				0 => FromHex::from_hex(clean(s)).unwrap_or(vec![]),
-				_ => FromHex::from_hex(&("0".to_string() + &(clean(s).to_string()))[..]).unwrap_or(vec![]),
+				_ => FromHex::from_hex(&("0".to_owned() + &(clean(s).to_owned()))[..]).unwrap_or(vec![]),
 			},
 			_ => vec![],
 		}
@@ -30,8 +30,8 @@ impl FromJson for Bytes {
 
 impl FromJson for BTreeMap<H256, H256> {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::Object(ref o) => o.iter().map(|(key, value)| (x!(&u256_from_str(key)), x!(&U256::from_json(value)))).collect(),
+		match *json {
+			Json::Object(ref o) => o.iter().map(|(key, value)| (x!(&u256_from_str(key)), x!(&U256::from_json(value)))).collect(),
 			_ => BTreeMap::new(),
 		}
 	}
@@ -39,8 +39,8 @@ impl FromJson for BTreeMap<H256, H256> {
 
 impl<T> FromJson for Vec<T> where T: FromJson {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::Array(ref o) => o.iter().map(|x|T::from_json(x)).collect(),
+		match *json {
+			Json::Array(ref o) => o.iter().map(|x|T::from_json(x)).collect(),
 			_ => Vec::new(),
 		}
 	}
@@ -48,9 +48,9 @@ impl<T> FromJson for Vec<T> where T: FromJson {
 
 impl<T> FromJson for Option<T> where T: FromJson {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::String(ref o) if o.is_empty() => None,
-			&Json::Null => None,
+		match *json {
+			Json::String(ref o) if o.is_empty() => None,
+			Json::Null => None,
 			_ => Some(FromJson::from_json(json)),
 		}
 	}
@@ -134,4 +134,4 @@ fn option_types() {
 	assert_eq!(None, v);
 	let v: Option<u16> = xjson!(&j["empty"]);
 	assert_eq!(None, v);
-}
\ No newline at end of file
+}
diff --git a/util/src/lib.rs b/util/src/lib.rs
index 4bc47e61c..ffa091c37 100644
--- a/util/src/lib.rs
+++ b/util/src/lib.rs
@@ -2,6 +2,7 @@
 #![feature(augmented_assignments)]
 #![feature(associated_consts)]
 #![feature(wrapping)]
+#![allow(needless_range_loop, match_bool)]
 //! Ethcore-util library
 //!
 //! ### Rust version:
diff --git a/util/src/misc.rs b/util/src/misc.rs
index e5efd33bb..d540ccf5b 100644
--- a/util/src/misc.rs
+++ b/util/src/misc.rs
@@ -14,13 +14,13 @@ impl<T> Diff<T> where T: Eq {
 	pub fn new(pre: T, post: T) -> Self { if pre == post { Diff::Same } else { Diff::Changed(pre, post) } }
 
 	/// Get the before value, if there is one.
-	pub fn pre(&self) -> Option<&T> { match self { &Diff::Died(ref x) | &Diff::Changed(ref x, _) => Some(x), _ => None } }
+	pub fn pre(&self) -> Option<&T> { match *self { Diff::Died(ref x) | Diff::Changed(ref x, _) => Some(x), _ => None } }
 
 	/// Get the after value, if there is one.
-	pub fn post(&self) -> Option<&T> { match self { &Diff::Born(ref x) | &Diff::Changed(_, ref x) => Some(x), _ => None } }
+	pub fn post(&self) -> Option<&T> { match *self { Diff::Born(ref x) | Diff::Changed(_, ref x) => Some(x), _ => None } }
 
 	/// Determine whether there was a change or not.
-	pub fn is_same(&self) -> bool { match self { &Diff::Same => true, _ => false }}
+	pub fn is_same(&self) -> bool { match *self { Diff::Same => true, _ => false }}
 }
 
 #[derive(PartialEq,Eq,Clone,Copy)]
diff --git a/util/src/network/connection.rs b/util/src/network/connection.rs
index f11c10384..6127cf838 100644
--- a/util/src/network/connection.rs
+++ b/util/src/network/connection.rs
@@ -86,7 +86,7 @@ impl Connection {
 
 	/// Add a packet to send queue.
 	pub fn send(&mut self, data: Bytes) {
-		if data.len() != 0 {
+		if !data.is_empty() {
 			self.send_queue.push_back(Cursor::new(data));
 		}
 		if !self.interest.is_writable() {
@@ -341,11 +341,8 @@ impl EncryptedConnection {
 		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
 		match self.read_state {
 			EncryptedConnectionState::Header => {
-				match try!(self.connection.readable()) {
-					Some(data)  => {
-						try!(self.read_header(&data));
-					},
-					None => {}
+				if let Some(data) = try!(self.connection.readable()) {
+					try!(self.read_header(&data));
 				};
 				Ok(None)
 			},
diff --git a/util/src/network/discovery.rs b/util/src/network/discovery.rs
index d2a4f21a2..1f2bd4e06 100644
--- a/util/src/network/discovery.rs
+++ b/util/src/network/discovery.rs
@@ -62,7 +62,7 @@ impl Discovery {
 			discovery_round: 0,
 			discovery_id: NodeId::new(),
 			discovery_nodes: HashSet::new(),
-			node_buckets: (0..NODE_BINS).map(|x| NodeBucket::new(x)).collect(),
+			node_buckets: (0..NODE_BINS).map(NodeBucket::new).collect(),
 		}
 	}
 
@@ -122,7 +122,8 @@ impl Discovery {
 		ret
 	}
 
-	fn nearest_node_entries<'b>(source: &NodeId, target: &NodeId, buckets: &'b Vec<NodeBucket>) -> Vec<&'b NodeId>
+	#[allow(cyclomatic_complexity)]
+	fn nearest_node_entries<'b>(source: &NodeId, target: &NodeId, buckets: &'b [NodeBucket]) -> Vec<&'b NodeId>
 	{
 		// send ALPHA FindNode packets to nodes we know, closest to target
 		const LAST_BIN: u32 = NODE_BINS - 1;
@@ -136,7 +137,7 @@ impl Discovery {
 		if head > 1 && tail != LAST_BIN {
 			while head != tail && head < NODE_BINS && count < BUCKET_SIZE
 			{
-				for n in buckets[head as usize].nodes.iter()
+				for n in &buckets[head as usize].nodes
 				{
 						if count < BUCKET_SIZE {
 							count += 1;
@@ -147,7 +148,7 @@ impl Discovery {
 						}
 				}
 				if count < BUCKET_SIZE && tail != 0 {
-					for n in buckets[tail as usize].nodes.iter() {
+					for n in &buckets[tail as usize].nodes {
 						if count < BUCKET_SIZE {
 							count += 1;
 							found.entry(Discovery::distance(target, &n)).or_insert(Vec::new()).push(n);
@@ -166,7 +167,7 @@ impl Discovery {
 		}
 		else if head < 2 {
 			while head < NODE_BINS && count < BUCKET_SIZE {
-				for n in buckets[head as usize].nodes.iter() {
+				for n in &buckets[head as usize].nodes {
 						if count < BUCKET_SIZE {
 							count += 1;
 							found.entry(Discovery::distance(target, &n)).or_insert(Vec::new()).push(n);
@@ -180,7 +181,7 @@ impl Discovery {
 		}
 		else {
 			while tail > 0 && count < BUCKET_SIZE {
-				for n in buckets[tail as usize].nodes.iter() {
+				for n in &buckets[tail as usize].nodes {
 						if count < BUCKET_SIZE {
 							count += 1;
 							found.entry(Discovery::distance(target, &n)).or_insert(Vec::new()).push(n);
diff --git a/util/src/network/handshake.rs b/util/src/network/handshake.rs
index ca95808b4..e7a669e25 100644
--- a/util/src/network/handshake.rs
+++ b/util/src/network/handshake.rs
@@ -93,21 +93,15 @@ impl Handshake {
 		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
 		match self.state {
 			HandshakeState::ReadingAuth => {
-				match try!(self.connection.readable()) {
-					Some(data)  => {
-						try!(self.read_auth(host, &data));
-						try!(self.write_ack());
-					},
-					None => {}
+				if let Some(data) = try!(self.connection.readable()) {
+					try!(self.read_auth(host, &data));
+					try!(self.write_ack());
 				};
 			},
 			HandshakeState::ReadingAck => {
-				match try!(self.connection.readable()) {
-					Some(data)  => {
-						try!(self.read_ack(host, &data));
-						self.state = HandshakeState::StartSession;
-					},
-					None => {}
+				if let Some(data) = try!(self.connection.readable()) {
+					try!(self.read_ack(host, &data));
+					self.state = HandshakeState::StartSession;
 				};
 			},
 			_ => { panic!("Unexpected state"); }
diff --git a/util/src/network/host.rs b/util/src/network/host.rs
index 37b58f1f0..060fd5217 100644
--- a/util/src/network/host.rs
+++ b/util/src/network/host.rs
@@ -175,7 +175,7 @@ impl<'s, 'io, Message> NetworkContext<'s, 'io, Message> where Message: Send + 's
 				s.info.client_version.clone()
 			},
 			_ => {
-				"unknown".to_string()
+				"unknown".to_owned()
 			}
 		}
 	}
@@ -213,7 +213,7 @@ impl HostInfo {
 	/// Increments and returns connection nonce.
 	pub fn next_nonce(&mut self) -> H256 {
 		self.nonce = self.nonce.sha3();
-		return self.nonce.clone();
+		self.nonce.clone()
 	}
 }
 
@@ -246,7 +246,7 @@ impl<Message> Host<Message> where Message: Send {
 				config: config,
 				nonce: H256::random(),
 				protocol_version: 4,
-				client_version: "parity".to_string(),
+				client_version: "parity".to_owned(),
 				listen_port: 0,
 				capabilities: Vec::new(),
 			},
@@ -274,11 +274,11 @@ impl<Message> Host<Message> where Message: Send {
 	}
 
 	fn have_session(&self, id: &NodeId) -> bool {
-		self.connections.iter().any(|e| match e { &ConnectionEntry::Session(ref s) => s.info.id.eq(&id), _ => false  })
+		self.connections.iter().any(|e| match *e { ConnectionEntry::Session(ref s) => s.info.id.eq(&id), _ => false  })
 	}
 
 	fn connecting_to(&self, id: &NodeId) -> bool {
-		self.connections.iter().any(|e| match e { &ConnectionEntry::Handshake(ref h) => h.id.eq(&id), _ => false  })
+		self.connections.iter().any(|e| match *e { ConnectionEntry::Handshake(ref h) => h.id.eq(&id), _ => false  })
 	}
 
 	fn connect_peers(&mut self, io: &mut IoContext<NetworkIoMessage<Message>>) {
@@ -303,7 +303,7 @@ impl<Message> Host<Message> where Message: Send {
 			}
 		}
 
-		for n in to_connect.iter() {
+		for n in &to_connect {
 			if n.peer_type == PeerType::Required {
 				if req_conn < IDEAL_PEERS {
 					self.connect_peer(&n.id, io);
@@ -318,7 +318,7 @@ impl<Message> Host<Message> where Message: Send {
 			let peer_count = 0;
 			let mut open_slots = IDEAL_PEERS - peer_count  - pending_count + req_conn;
 			if open_slots > 0 {
-				for n in to_connect.iter() {
+				for n in &to_connect {
 					if n.peer_type == PeerType::Optional && open_slots > 0 {
 						open_slots -= 1;
 						self.connect_peer(&n.id, io);
@@ -328,6 +328,7 @@ impl<Message> Host<Message> where Message: Send {
 		}
 	}
 
+	#[allow(single_match)]
 	fn connect_peer(&mut self, id: &NodeId, io: &mut IoContext<NetworkIoMessage<Message>>) {
 		if self.have_session(id)
 		{
@@ -376,6 +377,7 @@ impl<Message> Host<Message> where Message: Send {
 		trace!(target: "net", "accept");
 	}
 
+	#[allow(single_match)]
 	fn connection_writable<'s>(&'s mut self, token: StreamToken, io: &mut IoContext<'s, NetworkIoMessage<Message>>) {
 		let mut kill = false;
 		let mut create_session = false;
@@ -436,7 +438,7 @@ impl<Message> Host<Message> where Message: Send {
 				}) };
 				match sd {
 					SessionData::Ready => {
-						for (p, _) in self.handlers.iter_mut() {
+						for (p, _) in &mut self.handlers {
 							if s.have_capability(p)  {
 								ready_data.push(p);
 							}
@@ -475,11 +477,8 @@ impl<Message> Host<Message> where Message: Send {
 			h.read(&mut NetworkContext::new(io, p, Some(token), &mut self.connections, &mut self.timers), &token, packet_id, &data[1..]);
 		}
 
-		match self.connections.get_mut(token) {
-			Some(&mut ConnectionEntry::Session(ref mut s)) => {
-				s.reregister(io.event_loop).unwrap_or_else(|e| debug!(target: "net", "Session registration error: {:?}", e));
-			},
-			_ => (),
+		if let Some(&mut ConnectionEntry::Session(ref mut s)) = self.connections.get_mut(token) {
+			s.reregister(io.event_loop).unwrap_or_else(|e| debug!(target: "net", "Session registration error: {:?}", e));
 		}
 	}
 
@@ -523,7 +522,7 @@ impl<Message> Host<Message> where Message: Send {
 		match self.connections.get_mut(token) {
 			Some(&mut ConnectionEntry::Handshake(_)) => (), // just abandon handshake
 			Some(&mut ConnectionEntry::Session(ref mut s)) if s.is_ready() => {
-				for (p, _) in self.handlers.iter_mut() {
+				for (p, _) in &mut self.handlers {
 					if s.have_capability(p)  {
 						to_disconnect.push(p);
 					}
@@ -600,19 +599,20 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 			FIRST_CONNECTION ... LAST_CONNECTION => self.connection_timeout(token, io),
 			NODETABLE_DISCOVERY => {},
 			NODETABLE_MAINTAIN => {},
-			_ => match self.timers.get_mut(&token).map(|p| *p) {
-					Some(protocol) => match self.handlers.get_mut(protocol) {
+			_ => {
+				if let Some(protocol) = self.timers.get_mut(&token).map(|p| *p) {
+					match self.handlers.get_mut(protocol) {
 							None => { warn!(target: "net", "No handler found for protocol: {:?}", protocol) },
 							Some(h) => { h.timeout(&mut NetworkContext::new(io, protocol, Some(token), &mut self.connections, &mut self.timers), token); }
-					},
-					None => {} // time not registerd through us
+					};
+				} // else time not registerd through us
 			}
 		}
 	}
 
 	fn message<'s>(&'s mut self, io: &mut IoContext<'s, NetworkIoMessage<Message>>, message: &'s mut NetworkIoMessage<Message>) {
-		match message {
-			&mut NetworkIoMessage::AddHandler {
+		match *message {
+			NetworkIoMessage::AddHandler {
 				ref mut handler,
 				ref protocol,
 				ref versions
@@ -624,7 +624,7 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 					self.info.capabilities.push(CapabilityInfo { protocol: protocol, version: *v, packet_count:0 });
 				}
 			},
-			&mut NetworkIoMessage::Send {
+			NetworkIoMessage::Send {
 				ref peer,
 				ref packet_id,
 				ref protocol,
@@ -641,8 +641,8 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 					}
 				}
 			},
-			&mut NetworkIoMessage::User(ref message) => {
-				for (p, h) in self.handlers.iter_mut() {
+			NetworkIoMessage::User(ref message) => {
+				for (p, h) in &mut self.handlers {
 					h.message(&mut NetworkContext::new(io, p, None, &mut self.connections, &mut self.timers), &message);
 				}
 			}
diff --git a/util/src/network/node.rs b/util/src/network/node.rs
index 5c08e0a66..fd27e58e2 100644
--- a/util/src/network/node.rs
+++ b/util/src/network/node.rs
@@ -20,14 +20,16 @@ pub struct NodeEndpoint {
 	pub udp_port: u16
 }
 
-impl NodeEndpoint {
+impl FromStr for NodeEndpoint {
+	type Err = UtilError;
+
 	/// Create endpoint from string. Performs name resolution if given a host name.
 	fn from_str(s: &str) -> Result<NodeEndpoint, UtilError> {
 		let address = s.to_socket_addrs().map(|mut i| i.next());
 		match address {
 			Ok(Some(a)) => Ok(NodeEndpoint {
 				address: a,
-				address_str: s.to_string(),
+				address_str: s.to_owned(),
 				udp_port: a.port()
 			}),
 			Ok(_) => Err(UtilError::AddressResolve(None)),
diff --git a/util/src/network/session.rs b/util/src/network/session.rs
index 828e4b062..d20448fdd 100644
--- a/util/src/network/session.rs
+++ b/util/src/network/session.rs
@@ -182,7 +182,7 @@ impl Session {
 				// map to protocol
 				let protocol = self.info.capabilities[i].protocol;
 				let pid = packet_id - self.info.capabilities[i].id_offset;
-				return Ok(SessionData::Packet { data: packet.data, protocol: protocol, packet_id: pid } )
+				Ok(SessionData::Packet { data: packet.data, protocol: protocol, packet_id: pid } )
 			},
 			_ => {
 				debug!(target: "net", "Unkown packet: {:?}", packet_id);
@@ -212,7 +212,7 @@ impl Session {
 		// Intersect with host capabilities
 		// Leave only highset mutually supported capability version
 		let mut caps: Vec<SessionCapabilityInfo> = Vec::new();
-		for hc in host.capabilities.iter() {
+		for hc in &host.capabilities {
 			if peer_caps.iter().any(|c| c.protocol == hc.protocol && c.version == hc.version) {
 				caps.push(SessionCapabilityInfo {
 					protocol: hc.protocol,
diff --git a/util/src/overlaydb.rs b/util/src/overlaydb.rs
index 1006cd28c..0bda2660d 100644
--- a/util/src/overlaydb.rs
+++ b/util/src/overlaydb.rs
@@ -159,7 +159,7 @@ impl HashDB for OverlayDB {
 		match k {
 			Some(&(ref d, rc)) if rc > 0 => Some(d),
 			_ => {
-				let memrc = k.map(|&(_, rc)| rc).unwrap_or(0);
+				let memrc = k.map_or(0, |&(_, rc)| rc);
 				match self.payload(key) {
 					Some(x) => {
 						let (d, rc) = x;
@@ -184,16 +184,11 @@ impl HashDB for OverlayDB {
 		match k {
 			Some(&(_, rc)) if rc > 0 => true,
 			_ => {
-				let memrc = k.map(|&(_, rc)| rc).unwrap_or(0);
+				let memrc = k.map_or(0, |&(_, rc)| rc);
 				match self.payload(key) {
 					Some(x) => {
 						let (_, rc) = x;
-						if rc as i32 + memrc > 0 {
-							true
-						}
-						else {
-							false
-						}
+						rc as i32 + memrc > 0
 					}
 					// Replace above match arm with this once https://github.com/rust-lang/rust/issues/15287 is done.
 					//Some((d, rc)) if rc + memrc > 0 => true,
diff --git a/util/src/rlp/rlpstream.rs b/util/src/rlp/rlpstream.rs
index b8954ae6f..1487e3912 100644
--- a/util/src/rlp/rlpstream.rs
+++ b/util/src/rlp/rlpstream.rs
@@ -41,7 +41,7 @@ impl Stream for RlpStream {
 		stream
 	}
 
-	fn append<'a, E>(&'a mut self, object: &E) -> &'a mut RlpStream where E: Encodable {
+	fn append<E>(&mut self, object: &E) -> &mut RlpStream where E: Encodable {
 		// encode given value and add it at the end of the stream
 		object.encode(&mut self.encoder);
 
@@ -52,7 +52,7 @@ impl Stream for RlpStream {
 		self
 	}
 
-	fn append_list<'a>(&'a mut self, len: usize) -> &'a mut RlpStream {
+	fn append_list(&mut self, len: usize) -> &mut RlpStream {
 		match len {
 			0 => {
 				// we may finish, if the appended list len is equal 0
@@ -69,7 +69,7 @@ impl Stream for RlpStream {
 		self
 	}
 
-	fn append_empty_data<'a>(&'a mut self) -> &'a mut RlpStream {
+	fn append_empty_data(&mut self) -> &mut RlpStream {
 		// self push raw item
 		self.encoder.bytes.push(0x80);
 
diff --git a/util/src/rlp/rlptraits.rs b/util/src/rlp/rlptraits.rs
index 407d62daf..162f990fe 100644
--- a/util/src/rlp/rlptraits.rs
+++ b/util/src/rlp/rlptraits.rs
@@ -5,7 +5,7 @@ pub trait Decoder: Sized {
 		where F: FnOnce(&[u8]) -> Result<T, DecoderError>;
 
 	fn as_list(&self) -> Result<Vec<Self>, DecoderError>;
-	fn as_rlp<'a>(&'a self) -> &'a UntrustedRlp<'a>;
+	fn as_rlp(&self) -> &UntrustedRlp;
 	fn as_raw(&self) -> &[u8];
 }
 
@@ -231,7 +231,7 @@ pub trait Stream: Sized {
 	/// 	assert_eq!(out, vec![0xca, 0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o', b'g', 0x80]);
 	/// }
 	/// ```
-	fn append_list<'a>(&'a mut self, len: usize) -> &'a mut Self;
+	fn append_list(&mut self, len: usize) -> &mut Self;
 
 	/// Apends null to the end of stream, chainable.
 	///
@@ -246,7 +246,7 @@ pub trait Stream: Sized {
 	/// 	assert_eq!(out, vec![0xc2, 0x80, 0x80]);
 	/// }
 	/// ```
-	fn append_empty_data<'a>(&'a mut self) -> &'a mut Self;
+	fn append_empty_data(&mut self) -> &mut Self;
 
 	/// Appends raw (pre-serialised) RLP data. Use with caution. Chainable.
 	fn append_raw<'a>(&'a mut self, bytes: &[u8], item_count: usize) -> &'a mut Self;
diff --git a/util/src/rlp/untrusted_rlp.rs b/util/src/rlp/untrusted_rlp.rs
index 2bf33ba68..9c9246115 100644
--- a/util/src/rlp/untrusted_rlp.rs
+++ b/util/src/rlp/untrusted_rlp.rs
@@ -282,7 +282,7 @@ impl<'a> BasicDecoder<'a> {
 
 	/// Return first item info
 	fn payload_info(bytes: &[u8]) -> Result<PayloadInfo, DecoderError> {
-		let item = match bytes.first().map(|&x| x) {
+		let item = match bytes.first().cloned() {
 			None => return Err(DecoderError::RlpIsTooShort),
 			Some(0...0x7f) => PayloadInfo::new(0, 1),
 			Some(l @ 0x80...0xb7) => PayloadInfo::new(1, l as usize - 0x80),
@@ -318,7 +318,7 @@ impl<'a> Decoder for BasicDecoder<'a> {
 
 		let bytes = self.rlp.as_raw();
 
-		match bytes.first().map(|&x| x) {
+		match bytes.first().cloned() {
 			// rlp is too short
 			None => Err(DecoderError::RlpIsTooShort),
 			// single byt value
@@ -349,12 +349,12 @@ impl<'a> Decoder for BasicDecoder<'a> {
 
 	fn as_list(&self) -> Result<Vec<Self>, DecoderError> {
 		let v: Vec<BasicDecoder<'a>> = self.rlp.iter()
-			.map(| i | BasicDecoder::new(i))
+			.map(BasicDecoder::new)
 			.collect();
 		Ok(v)
 	}
 
-	fn as_rlp<'s>(&'s self) -> &'s UntrustedRlp<'s> {
+	fn as_rlp(&self) -> &UntrustedRlp {
 		&self.rlp
 	}
 }
@@ -399,6 +399,7 @@ impl<T> Decodable for Option<T> where T: Decodable {
 macro_rules! impl_array_decodable {
 	($index_type:ty, $len:expr ) => (
 		impl<T> Decodable for [T; $len] where T: Decodable {
+			#[allow(len_zero)]
 			fn decode<D>(decoder: &D) -> Result<Self, DecoderError>  where D: Decoder {
 				let decoders = try!(decoder.as_list());
 
diff --git a/util/src/squeeze.rs b/util/src/squeeze.rs
index e81a13793..f83c5cee9 100644
--- a/util/src/squeeze.rs
+++ b/util/src/squeeze.rs
@@ -41,7 +41,7 @@ pub trait Squeeze {
 
 impl<K, T> Squeeze for HashMap<K, T> where K: Eq + Hash + Clone + HeapSizeOf, T: HeapSizeOf {
 	fn squeeze(&mut self, size: usize) {
-		if self.len() == 0 {
+		if self.is_empty() {
 			return
 		}
 		
@@ -49,7 +49,7 @@ impl<K, T> Squeeze for HashMap<K, T> where K: Eq + Hash + Clone + HeapSizeOf, T:
 		let all_entries = size_of_entry * self.len();
 		let mut shrinked_size = all_entries;
 
-		while self.len() > 0 && shrinked_size > size {
+		while !self.is_empty() && shrinked_size > size {
 			// could be optimized
 			let key = self.keys().next().unwrap().clone();
 			self.remove(&key);
diff --git a/util/src/trie/triedb.rs b/util/src/trie/triedb.rs
index 9e4cf36e2..612bcdf7a 100644
--- a/util/src/trie/triedb.rs
+++ b/util/src/trie/triedb.rs
@@ -37,6 +37,7 @@ pub struct TrieDB<'db> {
 	pub hash_count: usize,
 }
 
+#[allow(wrong_self_convention)]
 impl<'db> TrieDB<'db> {
 	/// Create a new trie with the backing database `db` and `root`
 	/// Panics, if `root` does not exist
@@ -102,7 +103,7 @@ impl<'db> TrieDB<'db> {
 
 		match node {
 			Node::Extension(_, payload) => handle_payload(payload),
-			Node::Branch(payloads, _) => for payload in payloads.iter() { handle_payload(payload) },
+			Node::Branch(payloads, _) => for payload in &payloads { handle_payload(payload) },
 			_ => {},
 		}
 	}
@@ -140,12 +141,9 @@ impl<'db> TrieDB<'db> {
 			},
 			Node::Branch(ref nodes, ref value) => {
 				try!(writeln!(f, ""));
-				match value {
-					&Some(v) => {
-						try!(self.fmt_indent(f, deepness + 1));
-						try!(writeln!(f, "=: {:?}", v.pretty()))
-					},
-					&None => {}
+				if let Some(v) = *value {
+					try!(self.fmt_indent(f, deepness + 1));
+					try!(writeln!(f, "=: {:?}", v.pretty()))
 				}
 				for i in 0..16 {
 					match self.get_node(nodes[i]) {
diff --git a/util/src/trie/triedbmut.rs b/util/src/trie/triedbmut.rs
index 0f3dde4fb..bd39f87ae 100644
--- a/util/src/trie/triedbmut.rs
+++ b/util/src/trie/triedbmut.rs
@@ -49,6 +49,7 @@ enum MaybeChanged<'a> {
 	Changed(Bytes),
 }
 
+#[allow(wrong_self_convention)]
 impl<'db> TrieDBMut<'db> {
 	/// Create a new trie with the backing database `db` and empty `root`
 	/// Initialise to the state entailed by the genesis block.
@@ -144,7 +145,7 @@ impl<'db> TrieDBMut<'db> {
 
 		match node {
 			Node::Extension(_, payload) => handle_payload(payload),
-			Node::Branch(payloads, _) => for payload in payloads.iter() { handle_payload(payload) },
+			Node::Branch(payloads, _) => for payload in &payloads { handle_payload(payload) },
 			_ => {},
 		}
 	}
@@ -177,12 +178,9 @@ impl<'db> TrieDBMut<'db> {
 			},
 			Node::Branch(ref nodes, ref value) => {
 				try!(writeln!(f, ""));
-				match value {
-					&Some(v) => {
-						try!(self.fmt_indent(f, deepness + 1));
-						try!(writeln!(f, "=: {:?}", v.pretty()))
-					},
-					&None => {}
+				if let Some(v) = *value {
+					try!(self.fmt_indent(f, deepness + 1));
+					try!(writeln!(f, "=: {:?}", v.pretty()))
 				}
 				for i in 0..16 {
 					match self.get_node(nodes[i]) {
@@ -330,6 +328,7 @@ impl<'db> TrieDBMut<'db> {
 		}
 	}
 
+	#[allow(cyclomatic_complexity)]
 	/// Determine the RLP of the node, assuming we're inserting `partial` into the
 	/// node currently of data `old`. This will *not* delete any hash of `old` from the database;
 	/// it will just return the new RLP that includes the new node.
@@ -704,7 +703,7 @@ mod tests {
 	}
 
 	fn unpopulate_trie<'a, 'db>(t: &mut TrieDBMut<'db>, v: &Vec<(Vec<u8>, Vec<u8>)>) {
-		for i in v.iter() {
+		for i in &v {
 			let key: &[u8]= &i.0;
 			t.remove(&key);
 		}
diff --git a/util/src/uint.rs b/util/src/uint.rs
index ec70cddb2..3562a2b81 100644
--- a/util/src/uint.rs
+++ b/util/src/uint.rs
@@ -174,7 +174,7 @@ macro_rules! construct_uint {
 			#[inline]
 			fn byte(&self, index: usize) -> u8 {
 				let &$name(ref arr) = self;
-				(arr[index / 8] >> ((index % 8)) * 8) as u8
+				(arr[index / 8] >> (((index % 8)) * 8)) as u8
 			}
 
 			fn to_bytes(&self, bytes: &mut[u8]) {
@@ -328,16 +328,16 @@ macro_rules! construct_uint {
 
 		impl FromJson for $name {
 			fn from_json(json: &Json) -> Self {
-				match json {
-					&Json::String(ref s) => {
+				match *json {
+					Json::String(ref s) => {
 						if s.len() >= 2 && &s[0..2] == "0x" {
 							FromStr::from_str(&s[2..]).unwrap_or(Default::default())
 						} else {
 							Uint::from_dec_str(s).unwrap_or(Default::default())
 						}
 					},
-					&Json::U64(u) => From::from(u),
-					&Json::I64(i) => From::from(i as u64),
+					Json::U64(u) => From::from(u),
+					Json::I64(i) => From::from(i as u64),
 					_ => Uint::zero(),
 				}
 			}
@@ -370,7 +370,7 @@ macro_rules! construct_uint {
 				for i in 0..bytes.len() {
 					let rev = bytes.len() - 1 - i;
 					let pos = rev / 8;
-					ret[pos] += (bytes[i] as u64) << (rev % 8) * 8;
+					ret[pos] += (bytes[i] as u64) << ((rev % 8) * 8);
 				}
 				$name(ret)
 			}
@@ -382,7 +382,7 @@ macro_rules! construct_uint {
 			fn from_str(value: &str) -> Result<$name, Self::Err> {
 				let bytes: Vec<u8> = match value.len() % 2 == 0 {
 					true => try!(value.from_hex()),
-					false => try!(("0".to_string() + value).from_hex())
+					false => try!(("0".to_owned() + value).from_hex())
 				};
 
 				let bytes_ref: &[u8] = &bytes;