Merge pull request #170 from ethcore/clippy

Fixing clippy stuff
2016-01-22 11:55:35 +01:00 · 2016-01-22 11:55:35 +01:00 · f3d19262df
commit f3d19262df
parent caeb531494 694281cdf1
56 changed files with 341 additions and 369 deletions
--- a/Cargo.toml
+++ b/Cargo.toml
@ -20,6 +20,7 @@ time = "0.1"
 evmjit = { path = "rust-evmjit", optional = true }
 ethash = { path = "ethash" }
 num_cpus = "0.2"
+clippy = "*" # Always newest, since we use nightly

 [features]
 jit = ["evmjit"]
--- a/README.md
+++ b/README.md
@ -1 +1,5 @@
 # ethcore
+
+
+# Running clippy
+
--- a/src/account.rs
+++ b/src/account.rs
@ -103,7 +103,7 @@ impl Account {
 	/// Get (and cache) the contents of the trie's storage at `key`.
 	pub fn storage_at(&self, db: &HashDB, key: &H256) -> H256 {
 		self.storage_overlay.borrow_mut().entry(key.clone()).or_insert_with(||{
-			(Filth::Clean, H256::from(SecTrieDB::new(db, &self.storage_root).get(key.bytes()).map(|v| -> U256 {decode(v)}).unwrap_or(U256::zero())))
+			(Filth::Clean, H256::from(SecTrieDB::new(db, &self.storage_root).get(key.bytes()).map_or(U256::zero(), |v| -> U256 {decode(v)})))
 		}).1.clone()
 	}

@ -149,7 +149,7 @@ impl Account {
 	/// Provide a database to lookup `code_hash`. Should not be called if it is a contract without code.
 	pub fn cache_code(&mut self, db: &HashDB) -> bool {
 		// TODO: fill out self.code_cache;
-		return self.is_cached() ||
+		self.is_cached() ||
 			match self.code_hash {
 				Some(ref h) => match db.lookup(h) {
 					Some(x) => { self.code_cache = x.to_vec(); true },
@ -248,8 +248,8 @@ mod tests {

 		let a = Account::from_rlp(&rlp);
 		assert_eq!(a.storage_root().unwrap().hex(), "c57e1afb758b07f8d2c8f13a3b6e44fa5ff94ab266facc5a4fd3f062426e50b2");
-		assert_eq!(a.storage_at(&mut db, &H256::from(&U256::from(0x00u64))), H256::from(&U256::from(0x1234u64)));
-		assert_eq!(a.storage_at(&mut db, &H256::from(&U256::from(0x01u64))), H256::new());
+		assert_eq!(a.storage_at(&db, &H256::from(&U256::from(0x00u64))), H256::from(&U256::from(0x1234u64)));
+		assert_eq!(a.storage_at(&db, &H256::from(&U256::from(0x01u64))), H256::new());
 	}

 	#[test]
--- a/src/account_diff.rs
+++ b/src/account_diff.rs
@ -15,10 +15,10 @@ pub enum Existance {

 impl fmt::Display for Existance {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		match self {
-			&Existance::Born => try!(write!(f, "+++")),
-			&Existance::Alive => try!(write!(f, "***")),
-			&Existance::Died => try!(write!(f, "XXX")),
+		match *self {
+			Existance::Born => try!(write!(f, "+++")),
+			Existance::Alive => try!(write!(f, "***")),
+			Existance::Died => try!(write!(f, "XXX")),
 		}
 		Ok(())
 	}
@ -72,11 +72,11 @@ impl AccountDiff {
 					code: Diff::new(pre.code.clone(), post.code.clone()),
 					storage: storage.into_iter().map(|k|
 						(k.clone(), Diff::new(
-							pre.storage.get(&k).cloned().unwrap_or(H256::new()),
-							post.storage.get(&k).cloned().unwrap_or(H256::new())
+							pre.storage.get(&k).cloned().unwrap_or_else(H256::new),
+							post.storage.get(&k).cloned().unwrap_or_else(H256::new)
 						))).collect(),
 				};
-				if r.balance.is_same() && r.nonce.is_same() && r.code.is_same() && r.storage.len() == 0 {
+				if r.balance.is_same() && r.nonce.is_same() && r.code.is_same() && r.storage.is_empty() {
 					None
 				} else {
 					Some(r)
@ -112,16 +112,15 @@ impl fmt::Display for AccountDiff {
 			Diff::Changed(ref pre, ref post) => try!(write!(f, "${} ({} {} {})", post, pre, if pre > post {"-"} else {"+"}, *max(pre, post) - *min(pre, post))),
 			_ => {},
 		}
-		match self.code {
-			Diff::Born(ref x) => try!(write!(f, "  code {}", x.pretty())),
-			_ => {},
+		if let Diff::Born(ref x) = self.code {
+			try!(write!(f, "  code {}", x.pretty()));
 		}
 		try!(write!(f, "\n"));
-		for (k, dv) in self.storage.iter() {
-			match dv {
-				&Diff::Born(ref v) => try!(write!(f, "    +  {} => {}\n", interpreted_hash(k), interpreted_hash(v))),
-				&Diff::Changed(ref pre, ref post) => try!(write!(f, "    *  {} => {} (was {})\n", interpreted_hash(k), interpreted_hash(post), interpreted_hash(pre))),
-				&Diff::Died(_) => try!(write!(f, "    X  {}\n", interpreted_hash(k))),
+		for (k, dv) in &self.storage {
+			match *dv {
+				Diff::Born(ref v) => try!(write!(f, "    +  {} => {}\n", interpreted_hash(k), interpreted_hash(v))),
+				Diff::Changed(ref pre, ref post) => try!(write!(f, "    *  {} => {} (was {})\n", interpreted_hash(k), interpreted_hash(post), interpreted_hash(pre))),
+				Diff::Died(_) => try!(write!(f, "    X  {}\n", interpreted_hash(k))),
 				_ => {},
 			}
 		}
--- a/src/block.rs
+++ b/src/block.rs
@ -1,3 +1,5 @@
+#![allow(ptr_arg)] // Because of &LastHashes -> &Vec<_>
+
 use common::*;
 use engine::*;
 use state::*;
@ -173,7 +175,7 @@ impl<'x, 'y> OpenBlock<'x, 'y> {
 			timestamp: self.block.header.timestamp,
 			difficulty: self.block.header.difficulty.clone(),
 			last_hashes: self.last_hashes.clone(),		// TODO: should be a reference.
-			gas_used: self.block.archive.last().map(|t| t.receipt.gas_used).unwrap_or(U256::from(0)),
+			gas_used: self.block.archive.last().map_or(U256::zero(), |t| t.receipt.gas_used),
 			gas_limit: self.block.header.gas_limit.clone(),
 		}
 	}
@ -204,7 +206,7 @@ impl<'x, 'y> OpenBlock<'x, 'y> {
 		s.block.header.state_root = s.block.state.root().clone();
 		s.block.header.receipts_root = ordered_trie_root(s.block.archive.iter().map(|ref e| e.receipt.rlp_bytes()).collect());
 		s.block.header.log_bloom = s.block.archive.iter().fold(LogBloom::zero(), |mut b, e| {b |= &e.receipt.log_bloom; b});
-		s.block.header.gas_used = s.block.archive.last().map(|t| t.receipt.gas_used).unwrap_or(U256::from(0));
+		s.block.header.gas_used = s.block.archive.last().map_or(U256::zero(), |t| t.receipt.gas_used);
 		s.block.header.note_dirty();

 		ClosedBlock::new(s, uncle_bytes)
@ -255,7 +257,7 @@ impl SealedBlock {
 		let mut block_rlp = RlpStream::new_list(3);
 		self.block.header.stream_rlp(&mut block_rlp, Seal::With);
 		block_rlp.append_list(self.block.archive.len());
-		for e in self.block.archive.iter() { e.transaction.rlp_append(&mut block_rlp); }
+		for e in &self.block.archive { e.transaction.rlp_append(&mut block_rlp); }
 		block_rlp.append_raw(&self.uncle_bytes, 1);
 		block_rlp.out()
 	}
--- a/src/blockchain.rs
+++ b/src/blockchain.rs
@ -153,9 +153,8 @@ impl BlockProvider for BlockChain {
 	fn block(&self, hash: &H256) -> Option<Bytes> {
 		{
 			let read = self.blocks.read().unwrap();
-			match read.get(hash) {
-				Some(v) => return Some(v.clone()),
-				None => ()
+			if let Some(v) = read.get(hash) {
+				return Some(v.clone());
 			}
 		}

@ -188,7 +187,7 @@ impl BlockProvider for BlockChain {

 const COLLECTION_QUEUE_SIZE: usize = 2;
 const MIN_CACHE_SIZE: usize = 1;
-const MAX_CACHE_SIZE: usize = 1024 * 1024 * 1;
+const MAX_CACHE_SIZE: usize = 1024 * 1024;

 impl BlockChain {
 	/// Create new instance of blockchain from given Genesis
@ -527,9 +526,8 @@ impl BlockChain {
 		K: ExtrasSliceConvertable + Eq + Hash + Clone {
 		{
 			let read = cache.read().unwrap();
-			match read.get(hash) {
-				Some(v) => return Some(v.clone()),
-				None => ()
+			if let Some(v) = read.get(hash) {
+				return Some(v.clone());
 			}
 		}

@ -549,9 +547,8 @@ impl BlockChain {
 		T: ExtrasIndexable {
 		{
 			let read = cache.read().unwrap();
-			match read.get(hash) {
-				Some(_) => return true,
-				None => ()
+			if let Some(_) = read.get(hash) {
+				return true;
 			}
 		}

@ -670,6 +667,7 @@ mod tests {
 	}

 	#[test]
+	#[allow(cyclomatic_complexity)]
 	fn test_small_fork() {
 		let genesis = "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".from_hex().unwrap();
 		let b1 = "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".from_hex().unwrap();
--- a/src/builtin.rs
+++ b/src/builtin.rs
@ -94,16 +94,13 @@ pub fn new_builtin_exec(name: &str) -> Option<Box<Fn(&[u8], &mut [u8])>> {
 			if it.v == H256::from(&U256::from(27)) || it.v == H256::from(&U256::from(28)) {
 				let s = Signature::from_rsv(&it.r, &it.s, it.v[31] - 27);
 				if ec::is_valid(&s) {
-					match ec::recover(&s, &it.hash) {
-						Ok(p) => {
-							let r = p.as_slice().sha3();
-							// NICE: optimise and separate out into populate-like function
-							for i in 0..min(32, output.len()) {
-								output[i] = if i < 12 {0} else {r[i]};
-							}
+					if let Ok(p) = ec::recover(&s, &it.hash) {
+						let r = p.as_slice().sha3();
+						// NICE: optimise and separate out into populate-like function
+						for i in 0..min(32, output.len()) {
+							output[i] = if i < 12 {0} else {r[i]};
 						}
-						_ => {}
-					};
+					}
 				}
 			}
 		})),
--- a/src/ethereum/ethash.rs
+++ b/src/ethereum/ethash.rs
@ -32,13 +32,13 @@ impl Ethash {
 	}

 	fn u64_param(&self, name: &str) -> u64 {
-		*self.u64_params.write().unwrap().entry(name.to_string()).or_insert_with(||
-			self.spec().engine_params.get(name).map(|a| decode(&a)).unwrap_or(0u64))
+		*self.u64_params.write().unwrap().entry(name.to_owned()).or_insert_with(||
+			self.spec().engine_params.get(name).map_or(0u64, |a| decode(&a)))
 	}

 	fn u256_param(&self, name: &str) -> U256 {
-		*self.u256_params.write().unwrap().entry(name.to_string()).or_insert_with(||
-			self.spec().engine_params.get(name).map(|a| decode(&a)).unwrap_or(x!(0)))
+		*self.u256_params.write().unwrap().entry(name.to_owned()).or_insert_with(||
+			self.spec().engine_params.get(name).map_or(x!(0), |a| decode(&a)))
 	}
 }

@ -84,7 +84,7 @@ impl Engine for Ethash {
 	/// Apply the block reward on finalisation of the block.
 	/// This assumes that all uncles are valid uncles (i.e. of at least one generation before the current).
 	fn on_close_block(&self, block: &mut Block) {
-		let reward = self.spec().engine_params.get("blockReward").map(|a| decode(&a)).unwrap_or(U256::from(0u64));
+		let reward = self.spec().engine_params.get("blockReward").map_or(U256::from(0u64), |a| decode(&a));
 		let fields = block.fields();

 		// Bestow block reward
@ -153,6 +153,7 @@ impl Engine for Ethash {
 	}
 }

+#[allow(wrong_self_convention)] // to_ethash should take self
 impl Ethash {
 	fn calculate_difficuty(&self, header: &Header, parent: &Header) -> U256 {
 		const EXP_DIFF_PERIOD: u64 = 100000;
--- a/src/evm/factory.rs
+++ b/src/evm/factory.rs
@ -68,10 +68,11 @@ impl Factory {
 	fn jit() -> Box<Evm> {
 		unimplemented!()
 	}
-
+}
+impl Default for Factory {
 	/// Returns jitvm factory
 	#[cfg(feature = "jit")]
-	pub fn default() -> Factory {
+	fn default() -> Factory {
 		Factory {
 			evm: VMType::Jit
 		}
@ -79,7 +80,7 @@ impl Factory {

 	/// Returns native rust evm factory
 	#[cfg(not(feature = "jit"))]
-	pub fn default() -> Factory {
+	fn default() -> Factory {
 		Factory {
 			evm: VMType::Interpreter
 		}
--- a/src/evm/interpreter.rs
+++ b/src/evm/interpreter.rs
@ -72,7 +72,7 @@ impl<S : Copy> VecStack<S> {

 impl<S : fmt::Display> Stack<S> for VecStack<S> {
 	fn peek(&self, no_from_top: usize) -> &S {
-		return &self.stack[self.stack.len() - no_from_top - 1];
+		&self.stack[self.stack.len() - no_from_top - 1]
 	}

 	fn swap_with_top(&mut self, no_from_top: usize) {
@ -157,7 +157,7 @@ impl Memory for Vec<u8> {
 	}

 	fn size(&self) -> usize {
-		return self.len()
+		self.len()
 	}

 	fn read_slice(&self, init_off_u: U256, init_size_u: U256) -> &[u8] {
@ -228,6 +228,7 @@ struct CodeReader<'a> {
 	code: &'a Bytes
 }

+#[allow(len_without_is_empty)]
 impl<'a> CodeReader<'a> {
 	/// Get `no_of_bytes` from code and convert to U256. Move PC
 	fn read(&mut self, no_of_bytes: usize) -> U256 {
@ -330,6 +331,7 @@ impl evm::Evm for Interpreter {
 }

 impl Interpreter {
+	#[allow(cyclomatic_complexity)]
 	fn get_gas_cost_mem(&self,
 						ext: &evm::Ext,
 						instruction: Instruction,
@ -716,7 +718,7 @@ impl Interpreter {
 				let big_id = stack.pop_back();
 				let id = big_id.low_u64() as usize;
 				let max = id.wrapping_add(32);
-				let data = params.data.clone().unwrap_or(vec![]);
+				let data = params.data.clone().unwrap_or_else(|| vec![]);
 				let bound = cmp::min(data.len(), max);
 				if id < bound && big_id < U256::from(data.len()) {
 					let mut v = data[id..bound].to_vec();
@ -727,7 +729,7 @@ impl Interpreter {
 				}
 			},
 			instructions::CALLDATASIZE => {
-				stack.push(U256::from(params.data.clone().unwrap_or(vec![]).len()));
+				stack.push(U256::from(params.data.clone().map_or(0, |l| l.len())));
 			},
 			instructions::CODESIZE => {
 				stack.push(U256::from(code.len()));
@ -738,10 +740,10 @@ impl Interpreter {
 				stack.push(U256::from(len));
 			},
 			instructions::CALLDATACOPY => {
-				self.copy_data_to_memory(mem, stack, &params.data.clone().unwrap_or(vec![]));
+				self.copy_data_to_memory(mem, stack, &params.data.clone().unwrap_or_else(|| vec![]));
 			},
 			instructions::CODECOPY => {
-				self.copy_data_to_memory(mem, stack, &params.code.clone().unwrap_or(vec![]));
+				self.copy_data_to_memory(mem, stack, &params.code.clone().unwrap_or_else(|| vec![]));
 			},
 			instructions::EXTCODECOPY => {
 				let address = u256_to_address(&stack.pop_back());
@ -781,7 +783,7 @@ impl Interpreter {
 	fn copy_data_to_memory(&self,
 						   mem: &mut Memory,
 						   stack: &mut Stack<U256>,
-						   data: &Bytes) {
+						   data: &[u8]) {
 		let offset = stack.pop_back();
 		let index = stack.pop_back();
 		let size = stack.pop_back();
@ -1051,7 +1053,7 @@ impl Interpreter {
 		Ok(())
 	}

-	fn find_jump_destinations(&self, code: &Bytes) -> HashSet<CodePosition> {
+	fn find_jump_destinations(&self, code: &[u8]) -> HashSet<CodePosition> {
 		let mut jump_dests = HashSet::new();
 		let mut position = 0;

@ -1066,7 +1068,7 @@ impl Interpreter {
 			position += 1;
 		}

-		return jump_dests;
+		jump_dests
 	}
 }

--- a/src/evm/tests.rs
+++ b/src/evm/tests.rs
@ -19,7 +19,7 @@ struct FakeExt {
 	logs: Vec<FakeLogEntry>,
 	_suicides: HashSet<Address>,
 	info: EnvInfo,
-	_schedule: Schedule
+	schedule: Schedule
 }

 impl FakeExt {
@ -89,7 +89,7 @@ impl Ext for FakeExt {
 	}

 	fn schedule(&self) -> &Schedule {
-		&self._schedule
+		&self.schedule
 	}

 	fn env_info(&self) -> &EnvInfo {
@ -122,7 +122,7 @@ fn test_stack_underflow() {
 	};
 	
 	match err {
-		evm::Error::StackUnderflow {instruction: _, wanted, on_stack} => {
+		evm::Error::StackUnderflow {wanted, on_stack, ..} => {
 			assert_eq!(wanted, 2);
 			assert_eq!(on_stack, 0);
 		}
--- a/src/executive.rs
+++ b/src/executive.rs
@ -75,7 +75,7 @@ impl<'a> Executive<'a> {
 	}

 	/// Creates `Externalities` from `Executive`.
-	pub fn to_externalities<'_>(&'_ mut self, origin_info: OriginInfo, substate: &'_ mut Substate, output: OutputPolicy<'_>) -> Externalities {
+	pub fn as_externalities<'_>(&'_ mut self, origin_info: OriginInfo, substate: &'_ mut Substate, output: OutputPolicy<'_>) -> Externalities {
 		Externalities::new(self.state, self.info, self.engine, self.depth, origin_info, substate, output)
 	}

@ -123,8 +123,8 @@ impl<'a> Executive<'a> {

 		let mut substate = Substate::new();

-		let res = match t.action() {
-			&Action::Create => {
+		let res = match *t.action() {
+			Action::Create => {
 				let new_address = contract_address(&sender, &nonce);
 				let params = ActionParams {
 					code_address: new_address.clone(),
@ -139,7 +139,7 @@ impl<'a> Executive<'a> {
 				};
 				self.create(params, &mut substate)
 			},
-			&Action::Call(ref address) => {
+			Action::Call(ref address) => {
 				let params = ActionParams {
 					code_address: address.clone(),
 					address: address.clone(),
@ -177,7 +177,7 @@ impl<'a> Executive<'a> {
 			// if destination is builtin, try to execute it
 			
 			let default = [];
-			let data = if let &Some(ref d) = &params.data { d as &[u8] } else { &default as &[u8] };
+			let data = if let Some(ref d) = params.data { d as &[u8] } else { &default as &[u8] };

 			let cost = self.engine.cost_of_builtin(&params.code_address, data);
 			match cost <= params.gas {
@ -198,7 +198,7 @@ impl<'a> Executive<'a> {
 			let mut unconfirmed_substate = Substate::new();

 			let res = {
-				let mut ext = self.to_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::Return(output));
+				let mut ext = self.as_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::Return(output));
 				self.engine.vm_factory().create().exec(params, &mut ext)
 			};

@ -230,7 +230,7 @@ impl<'a> Executive<'a> {
 		self.state.transfer_balance(&params.sender, &params.address, &params.value);

 		let res = {
-			let mut ext = self.to_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::InitContract);
+			let mut ext = self.as_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::InitContract);
 			self.engine.vm_factory().create().exec(params, &mut ext)
 		};
 		self.enact_result(&res, substate, unconfirmed_substate, backup);
@ -248,7 +248,7 @@ impl<'a> Executive<'a> {
 		let refunds_bound = sstore_refunds + suicide_refunds;

 		// real ammount to refund
-		let gas_left_prerefund = match &result { &Ok(x) => x, _ => x!(0) };
+		let gas_left_prerefund = match result { Ok(x) => x, _ => x!(0) };
 		let refunded = cmp::min(refunds_bound, (t.gas - gas_left_prerefund) / U256::from(2));
 		let gas_left = gas_left_prerefund + refunded;

@ -265,7 +265,7 @@ impl<'a> Executive<'a> {
 		self.state.add_balance(&self.info.author, &fees_value);

 		// perform suicides
-		for address in substate.suicides.iter() {
+		for address in &substate.suicides {
 			trace!("Killing {}", address);
 			self.state.kill_account(address);
 		}
@ -273,11 +273,7 @@ impl<'a> Executive<'a> {
 		match result { 
 			Err(evm::Error::Internal) => Err(ExecutionError::Internal),
 			// TODO [ToDr] BadJumpDestination @debris - how to handle that?
-			Err(evm::Error::OutOfGas) 
-				| Err(evm::Error::BadJumpDestination { destination: _ }) 
-				| Err(evm::Error::BadInstruction { instruction: _ }) 
-				| Err(evm::Error::StackUnderflow {instruction: _, wanted: _, on_stack: _})
-				| Err(evm::Error::OutOfStack {instruction: _, wanted: _, limit: _}) => {
+			Err(_) => {
 				Ok(Executed {
 					gas: t.gas,
 					gas_used: t.gas,
@ -302,15 +298,15 @@ impl<'a> Executive<'a> {

 	fn enact_result(&mut self, result: &evm::Result, substate: &mut Substate, un_substate: Substate, backup: State) {
 		// TODO: handle other evm::Errors same as OutOfGas once they are implemented
-		match result {
-			&Err(evm::Error::OutOfGas)
-				| &Err(evm::Error::BadJumpDestination { destination: _ }) 
-				| &Err(evm::Error::BadInstruction { instruction: _ }) 
-				| &Err(evm::Error::StackUnderflow {instruction: _, wanted: _, on_stack: _})
-				| &Err(evm::Error::OutOfStack {instruction: _, wanted: _, limit: _}) => {
+		match *result {
+			Err(evm::Error::OutOfGas)
+				| Err(evm::Error::BadJumpDestination {..}) 
+				| Err(evm::Error::BadInstruction {.. }) 
+				| Err(evm::Error::StackUnderflow {..})
+				| Err(evm::Error::OutOfStack {..}) => {
 				self.state.revert(backup);
 			},
-			&Ok(_) | &Err(evm::Error::Internal) => substate.accrue(un_substate)
+			Ok(_) | Err(evm::Error::Internal) => substate.accrue(un_substate)
 		}
 	}
 }
--- a/src/externalities.rs
+++ b/src/externalities.rs
@ -158,9 +158,10 @@ impl<'a> Ext for Externalities<'a> {
 	}

 	fn extcode(&self, address: &Address) -> Bytes {
-		self.state.code(address).unwrap_or(vec![])
+		self.state.code(address).unwrap_or_else(|| vec![])
 	}

+	#[allow(match_ref_pats)]
 	fn ret(&mut self, gas: &U256, data: &[u8]) -> Result<U256, evm::Error> {
 		match &mut self.output {
 			&mut OutputPolicy::Return(BytesRef::Fixed(ref mut slice)) => unsafe {
--- a/src/header.rs
+++ b/src/header.rs
@ -171,9 +171,10 @@ impl Header {
 		s.append(&self.gas_used);
 		s.append(&self.timestamp);
 		s.append(&self.extra_data);
-		match with_seal {
-			Seal::With => for b in self.seal.iter() { s.append_raw(&b, 1); },
-			_ => {}
+		if let Seal::With = with_seal {
+			for b in &self.seal { 
+				s.append_raw(&b, 1); 
+			}
 		}
 	}

@ -236,7 +237,7 @@ impl Encodable for Header {
 			self.timestamp.encode(e);
 			self.extra_data.encode(e);

-			for b in self.seal.iter() {
+			for b in &self.seal {
 				e.emit_raw(&b);
 			}
 		})
--- a/src/lib.rs
+++ b/src/lib.rs
@ -1,8 +1,11 @@
 #![warn(missing_docs)]
 #![feature(cell_extras)]
 #![feature(augmented_assignments)]
-//#![feature(plugin)]
+#![feature(plugin)]
 //#![plugin(interpolate_idents)]
+#![plugin(clippy)]
+#![allow(needless_range_loop, match_bool)]
+
 //! Ethcore's ethereum implementation
 //!
 //! ### Rust version
@ -73,7 +76,6 @@
 //!       sudo make install
 //!       sudo ldconfig
 //!       ```
-
 #[macro_use]
 extern crate log;
 extern crate rustc_serialize;
--- a/src/pod_state.rs
+++ b/src/pod_state.rs
@ -26,10 +26,10 @@ impl FromJson for PodState {
 			let code = acc.find("code").map(&Bytes::from_json);
 			if balance.is_some() || nonce.is_some() || storage.is_some() || code.is_some() {
 				state.insert(address_from_hex(address), PodAccount{
-					balance: balance.unwrap_or(U256::zero()),
-					nonce: nonce.unwrap_or(U256::zero()),
-					storage: storage.unwrap_or(BTreeMap::new()),
-					code: code.unwrap_or(Vec::new())
+					balance: balance.unwrap_or_else(U256::zero),
+					nonce: nonce.unwrap_or_else(U256::zero),
+					storage: storage.unwrap_or_else(BTreeMap::new),
+					code: code.unwrap_or_else(Vec::new)
 				});
 			}
 			state
--- a/src/receipt.rs
+++ b/src/receipt.rs
@ -36,7 +36,7 @@ impl RlpStandard for Receipt {
 		// TODO: make work:
 		//s.append(&self.logs);
 		s.append_list(self.logs.len());
-		for l in self.logs.iter() {
+		for l in &self.logs {
 			l.rlp_append(s);
 		}
 	}
--- a/src/service.rs
+++ b/src/service.rs
@ -53,20 +53,13 @@ impl IoHandler<NetSyncMessage> for ClientIoHandler {
 	fn initialize<'s>(&'s mut self, _io: &mut IoContext<'s, NetSyncMessage>) {
 	}

+	#[allow(match_ref_pats)]
 	fn message<'s>(&'s mut self, _io: &mut IoContext<'s, NetSyncMessage>, net_message: &'s mut NetSyncMessage) {
-		match net_message {
-			&mut UserMessage(ref mut message) =>  {
-				match message {
-					&mut SyncMessage::BlockVerified => {
-						self.client.write().unwrap().import_verified_blocks();
-					},
-					_ => {}, // ignore other messages
-				}
-
+		if let &mut UserMessage(ref mut message) = net_message {
+			if let &mut SyncMessage::BlockVerified= message {
+				self.client.write().unwrap().import_verified_blocks();
 			}
-			_ => {}, // ignore other messages
 		}
-
 	}
 }

--- a/src/spec.rs
+++ b/src/spec.rs
@ -10,7 +10,7 @@ pub fn gzip64res_to_json(source: &[u8]) -> Json {
 	let data = source.from_base64().expect("Genesis block is malformed!");
 	let data_ref: &[u8] = &data;
 	let mut decoder = GzDecoder::new(data_ref).expect("Gzip is invalid");
-	let mut s: String = "".to_string();
+	let mut s: String = "".to_owned();
 	decoder.read_to_string(&mut s).expect("Gzip is invalid");
 	Json::from_str(&s).expect("Json is invalid")
 }
@ -18,14 +18,14 @@ pub fn gzip64res_to_json(source: &[u8]) -> Json {
 /// Convert JSON value to equivlaent RLP representation.
 // TODO: handle container types.
 fn json_to_rlp(json: &Json) -> Bytes {
-	match json {
-		&Json::Boolean(o) => encode(&(if o {1u64} else {0})),
-		&Json::I64(o) => encode(&(o as u64)),
-		&Json::U64(o) => encode(&o),
-		&Json::String(ref s) if s.len() >= 2 && &s[0..2] == "0x" && U256::from_str(&s[2..]).is_ok() => {
+	match *json {
+		Json::Boolean(o) => encode(&(if o {1u64} else {0})),
+		Json::I64(o) => encode(&(o as u64)),
+		Json::U64(o) => encode(&o),
+		Json::String(ref s) if s.len() >= 2 && &s[0..2] == "0x" && U256::from_str(&s[2..]).is_ok() => {
 			encode(&U256::from_str(&s[2..]).unwrap())
 		},
-		&Json::String(ref s) => {
+		Json::String(ref s) => {
 			encode(s)
 		},
 		_ => panic!()
@ -108,6 +108,7 @@ pub struct Spec {
 	state_root_memo: RwLock<Option<H256>>,
 }

+#[allow(wrong_self_convention)] // because to_engine(self) should be to_engine(&self)
 impl Spec {
 	/// Convert this object into a boxed Engine of the right underlying type.
 	// TODO avoid this hard-coded nastiness - use dynamic-linked plugin framework instead.
@ -185,13 +186,13 @@ impl FromJson for Spec {
 						builtins.insert(addr.clone(), builtin);
 					}
 				}
-				let balance = acc.find("balance").and_then(|x| match x { &Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
-				let nonce = acc.find("nonce").and_then(|x| match x { &Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
+				let balance = acc.find("balance").and_then(|x| match *x { Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
+				let nonce = acc.find("nonce").and_then(|x| match *x { Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
 //				let balance = if let Some(&Json::String(ref b)) = acc.find("balance") {U256::from_dec_str(b).unwrap_or(U256::from(0))} else {U256::from(0)};
 //				let nonce = if let Some(&Json::String(ref n)) = acc.find("nonce") {U256::from_dec_str(n).unwrap_or(U256::from(0))} else {U256::from(0)};
 				// TODO: handle code & data if they exist.
 				if balance.is_some() || nonce.is_some() {
-					state.insert(addr, GenesisAccount { balance: balance.unwrap_or(U256::from(0)), nonce: nonce.unwrap_or(U256::from(0)) });
+					state.insert(addr, GenesisAccount { balance: balance.unwrap_or_else(U256::zero), nonce: nonce.unwrap_or_else(U256::zero) });
 				}
 			}
 		}
@ -215,8 +216,8 @@ impl FromJson for Spec {

 		
 		Spec {
-			name: json.find("name").map(|j| j.as_string().unwrap()).unwrap_or("unknown").to_string(),
-			engine_name: json["engineName"].as_string().unwrap().to_string(),
+			name: json.find("name").map_or("unknown", |j| j.as_string().unwrap()).to_owned(),
+			engine_name: json["engineName"].as_string().unwrap().to_owned(),
 			engine_params: json_to_rlp_map(&json["params"]),
 			builtins: builtins,
 			parent_hash: H256::from_str(&genesis["parentHash"].as_string().unwrap()[2..]).unwrap(),
@ -242,7 +243,7 @@ impl Spec {
 			let mut root = H256::new(); 
 			{
 				let mut t = SecTrieDBMut::new(db, &mut root);
-				for (address, account) in self.genesis_state.iter() {
+				for (address, account) in &self.genesis_state {
 					t.insert(address.as_slice(), &account.rlp());
 				}
 			}
--- a/src/state.rs
+++ b/src/state.rs
@ -88,22 +88,22 @@ impl State {

 	/// Get the balance of account `a`.
 	pub fn balance(&self, a: &Address) -> U256 {
-		self.get(a, false).as_ref().map(|account| account.balance().clone()).unwrap_or(U256::from(0u8))
+		self.get(a, false).as_ref().map_or(U256::zero(), |account| account.balance().clone())
 	}

 	/// Get the nonce of account `a`.
 	pub fn nonce(&self, a: &Address) -> U256 {
-		self.get(a, false).as_ref().map(|account| account.nonce().clone()).unwrap_or(U256::from(0u8))
+		self.get(a, false).as_ref().map_or(U256::zero(), |account| account.nonce().clone())
 	}

 	/// Mutate storage of account `a` so that it is `value` for `key`.
 	pub fn storage_at(&self, a: &Address, key: &H256) -> H256 {
-		self.get(a, false).as_ref().map(|a|a.storage_at(&self.db, key)).unwrap_or(H256::new())	
+		self.get(a, false).as_ref().map_or(H256::new(), |a|a.storage_at(&self.db, key))	
 	}

 	/// Mutate storage of account `a` so that it is `value` for `key`.
 	pub fn code(&self, a: &Address) -> Option<Bytes> {
-		self.get(a, true).as_ref().map(|a|a.code().map(|x|x.to_vec())).unwrap_or(None)
+		self.get(a, true).as_ref().map_or(None, |a|a.code().map(|x|x.to_vec()))
 	}

 	/// Add `incr` to the balance of account `a`.
@ -170,6 +170,7 @@ impl State {

 	/// Commit accounts to SecTrieDBMut. This is similar to cpp-ethereum's dev::eth::commit.
 	/// `accounts` is mutable because we may need to commit the code or storage and record that.
+	#[allow(match_ref_pats)]
 	pub fn commit_into(db: &mut HashDB, root: &mut H256, accounts: &mut HashMap<Address, Option<Account>>) {
 		// first, commit the sub trees.
 		// TODO: is this necessary or can we dispense with the `ref mut a` for just `a`?
@ -186,9 +187,9 @@ impl State {
 		{
 			let mut trie = SecTrieDBMut::from_existing(db, root);
 			for (address, ref a) in accounts.iter() {
-				match a {
-					&&Some(ref account) => trie.insert(address, &account.rlp()),
-					&&None => trie.remove(address),
+				match **a {
+					Some(ref account) => trie.insert(address, &account.rlp()),
+					None => trie.remove(address),
 				}
 			}
 		}
@ -210,7 +211,7 @@ impl State {
 	pub fn to_hashmap_pod(&self) -> HashMap<Address, PodAccount> {
 		// TODO: handle database rather than just the cache.
 		self.cache.borrow().iter().fold(HashMap::new(), |mut m, (add, opt)| {
-			if let &Some(ref acc) = opt {
+			if let Some(ref acc) = *opt {
 				m.insert(add.clone(), PodAccount::from_account(acc));
 			}
 			m
@ -221,7 +222,7 @@ impl State {
 	pub fn to_pod(&self) -> PodState {
 		// TODO: handle database rather than just the cache.
 		PodState::new(self.cache.borrow().iter().fold(BTreeMap::new(), |mut m, (add, opt)| {
-			if let &Some(ref acc) = opt {
+			if let Some(ref acc) = *opt {
 				m.insert(add.clone(), PodAccount::from_account(acc));
 			}
 			m
--- a/src/state_diff.rs
+++ b/src/state_diff.rs
@ -15,7 +15,7 @@ impl StateDiff {

 impl fmt::Display for StateDiff {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		for (add, acc) in self.0.iter() {
+		for (add, acc) in &self.0 {
 			try!(write!(f, "{} {}: {}", acc.existance(), add, acc));
 		}
 		Ok(())
--- a/src/sync/chain.rs
+++ b/src/sync/chain.rs
@ -212,7 +212,7 @@ impl ChainSync {
 		self.downloading_bodies.clear();
 		self.headers.clear();
 		self.bodies.clear();
-		for (_, ref mut p) in self.peers.iter_mut() {
+		for (_, ref mut p) in &mut self.peers {
 			p.asking_blocks.clear();
 		}
 		self.header_ids.clear();
@ -268,6 +268,7 @@ impl ChainSync {
 		Ok(())
 	}

+	#[allow(cyclomatic_complexity)]
 	/// Called by peer once it has new block headers during sync
 	fn on_peer_block_headers(&mut self, io: &mut SyncIo, peer_id: PeerId, r: &UntrustedRlp) -> Result<(), PacketDecodeError> {
 		self.reset_peer_asking(peer_id, PeerAsking::BlockHeaders);
@ -375,7 +376,7 @@ impl ChainSync {
 				transactions_root: tx_root,
 				uncles: uncles
 			};
-			match self.header_ids.get(&header_id).map(|n| *n) {
+			match self.header_ids.get(&header_id).cloned() {
 				Some(n) => {
 					self.header_ids.remove(&header_id);
 					self.bodies.insert_item(n, body.as_raw().to_vec());
@ -699,16 +700,13 @@ impl ChainSync {
 	/// Used to recover from an error and re-download parts of the chain detected as bad.
 	fn remove_downloaded_blocks(&mut self, start: BlockNumber) {
 		for n in self.headers.get_tail(&start) {
-			match self.headers.find_item(&n) {
-				Some(ref header_data) => {
-					let header_to_delete = HeaderView::new(&header_data.data);
-					let header_id = HeaderId {
-						transactions_root: header_to_delete.transactions_root(),
-						uncles: header_to_delete.uncles_hash()
-					};
-					self.header_ids.remove(&header_id);
-				},
-				None => {}
+			if let Some(ref header_data) = self.headers.find_item(&n) {
+				let header_to_delete = HeaderView::new(&header_data.data);
+				let header_id = HeaderId {
+					transactions_root: header_to_delete.transactions_root(),
+					uncles: header_to_delete.uncles_hash()
+				};
+				self.header_ids.remove(&header_id);
 			}
 			self.downloading_bodies.remove(&n);
 			self.downloading_headers.remove(&n);
@ -796,12 +794,9 @@ impl ChainSync {
 		packet.append(&chain.best_block_hash);
 		packet.append(&chain.genesis_hash);
 		//TODO: handle timeout for status request
-		match io.send(peer_id, STATUS_PACKET, packet.out()) {
-			Err(e) => {
-				warn!(target:"sync", "Error sending status request: {:?}", e);
-				io.disable_peer(peer_id);
-			}
-			Ok(_) => ()
+		if let Err(e) = io.send(peer_id, STATUS_PACKET, packet.out()) {
+			warn!(target:"sync", "Error sending status request: {:?}", e);
+			io.disable_peer(peer_id);
 		}
 	}

@ -837,12 +832,9 @@ impl ChainSync {
 		let mut data = Bytes::new();
 		let inc = (skip + 1) as BlockNumber;
 		while number <= last && number > 0 && count < max_count {
-			match io.chain().block_header_at(number) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					count += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().block_header_at(number) {
+				data.append(&mut hdr);
+				count += 1;
 			}
 			if reverse {
 				if number <= inc {
@ -874,12 +866,9 @@ impl ChainSync {
 		let mut added = 0usize;
 		let mut data = Bytes::new();
 		for i in 0..count {
-			match io.chain().block_body(&try!(r.val_at::<H256>(i))) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					added += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().block_body(&try!(r.val_at::<H256>(i))) {
+				data.append(&mut hdr);
+				added += 1;
 			}
 		}
 		let mut rlp = RlpStream::new_list(added);
@ -901,12 +890,9 @@ impl ChainSync {
 		let mut added = 0usize;
 		let mut data = Bytes::new();
 		for i in 0..count {
-			match io.chain().state_data(&try!(r.val_at::<H256>(i))) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					added += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().state_data(&try!(r.val_at::<H256>(i))) {
+				data.append(&mut hdr);
+				added += 1;
 			}
 		}
 		let mut rlp = RlpStream::new_list(added);
@ -927,12 +913,9 @@ impl ChainSync {
 		let mut added = 0usize;
 		let mut data = Bytes::new();
 		for i in 0..count {
-			match io.chain().block_receipts(&try!(r.val_at::<H256>(i))) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					added += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().block_receipts(&try!(r.val_at::<H256>(i))) {
+				data.append(&mut hdr);
+				added += 1;
 			}
 		}
 		let mut rlp = RlpStream::new_list(added);
--- a/src/sync/io.rs
+++ b/src/sync/io.rs
@ -14,7 +14,7 @@ pub trait SyncIo {
 	/// Send a packet to a peer.
 	fn send(&mut self, peer_id: PeerId, packet_id: PacketId, data: Vec<u8>) -> Result<(), UtilError>;
 	/// Get the blockchain
-	fn chain<'s>(&'s mut self) -> &'s mut BlockChainClient;
+	fn chain(&mut self) -> &mut BlockChainClient;
 	/// Returns peer client identifier string
 	fn peer_info(&self, peer_id: PeerId) -> String {
 		peer_id.to_string()
@ -50,7 +50,7 @@ impl<'s, 'h, 'op> SyncIo for NetSyncIo<'s, 'h, 'op> {
 		self.network.send(peer_id, packet_id, data)
 	}

-	fn chain<'a>(&'a mut self) -> &'a mut BlockChainClient {
+	fn chain(&mut self) -> &mut BlockChainClient {
 		self.chain
 	}

--- a/src/sync/range_collection.rs
+++ b/src/sync/range_collection.rs
@ -29,7 +29,7 @@ pub trait RangeCollection<K, V> {
 	/// Remove all elements >= `tail`
 	fn insert_item(&mut self, key: K, value: V);
 	/// Get an iterator over ranges
-	fn range_iter<'c>(&'c self) -> RangeIterator<'c, K, V>;
+	fn range_iter(& self) -> RangeIterator<K, V>;
 }

 /// Range iterator. For each range yelds a key for the first element of the range and a vector of values.
@ -60,7 +60,7 @@ impl<'c, K:'c, V:'c> Iterator for RangeIterator<'c, K, V> where K: Add<Output =
 }

 impl<K, V> RangeCollection<K, V> for Vec<(K, Vec<V>)> where K: Ord + PartialEq + Add<Output = K> + Sub<Output = K> + Copy + FromUsize + ToUsize {
-	fn range_iter<'c>(&'c self) -> RangeIterator<'c, K, V> {
+	fn range_iter(&self) -> RangeIterator<K, V> {
 		RangeIterator {
 			range: self.len(),
 			collection: self
@ -191,6 +191,7 @@ impl<K, V> RangeCollection<K, V> for Vec<(K, Vec<V>)> where K: Ord + PartialEq +
 }

 #[test]
+#[allow(cyclomatic_complexity)]
 fn test_range() {
 	use std::cmp::{Ordering};

--- a/src/sync/tests.rs
+++ b/src/sync/tests.rs
@ -64,7 +64,7 @@ impl BlockChainClient for TestBlockChainClient {
 	}

 	fn block(&self, h: &H256) -> Option<Bytes> {
-		self.blocks.get(h).map(|b| b.clone())
+		self.blocks.get(h).cloned()
 	}

 	fn block_status(&self, h: &H256) -> BlockStatus {
@ -208,7 +208,7 @@ impl<'p> SyncIo for TestIo<'p> {
 		Ok(())
 	}

-	fn chain<'a>(&'a mut self) -> &'a mut BlockChainClient {
+	fn chain(&mut self) -> &mut BlockChainClient {
 		self.chain
 	}
 }
@ -265,14 +265,11 @@ impl TestNet {

 	pub fn sync_step(&mut self) {
 		for peer in 0..self.peers.len() {
-			match self.peers[peer].queue.pop_front() {
-				Some(packet) => {
-					let mut p = self.peers.get_mut(packet.recipient).unwrap();
-					trace!("--- {} -> {} ---", peer, packet.recipient);
-					p.sync.on_packet(&mut TestIo::new(&mut p.chain, &mut p.queue, Some(peer as PeerId)), peer as PeerId, packet.packet_id, &packet.data);
-					trace!("----------------");
-				},
-				None => {}
+			if let Some(packet) = self.peers[peer].queue.pop_front() {
+				let mut p = self.peers.get_mut(packet.recipient).unwrap();
+				trace!("--- {} -> {} ---", peer, packet.recipient);
+				p.sync.on_packet(&mut TestIo::new(&mut p.chain, &mut p.queue, Some(peer as PeerId)), peer as PeerId, packet.packet_id, &packet.data);
+				trace!("----------------");
 			}
 			let mut p = self.peers.get_mut(peer).unwrap();
 			p.sync.maintain_sync(&mut TestIo::new(&mut p.chain, &mut p.queue, None));
--- a/src/tests/executive.rs
+++ b/src/tests/executive.rs
@ -168,7 +168,7 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 		let mut fail = false;
 		//let mut fail_unless = |cond: bool| if !cond && !fail { failed.push(name.to_string()); fail = true };
 		let mut fail_unless = |cond: bool, s: &str | if !cond && !fail { 
-			failed.push(format!("[{}] {}: {}", vm, name.to_string(), s)); 
+			failed.push(format!("[{}] {}: {}", vm, name, s)); 
 			fail = true 
 		};
 	
@ -245,7 +245,7 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 				test.find("post").map(|pre| for (addr, s) in pre.as_object().unwrap() {
 					let address = Address::from(addr.as_ref());

-					fail_unless(state.code(&address).unwrap_or(vec![]) == Bytes::from_json(&s["code"]), "code is incorrect");
+					fail_unless(state.code(&address).unwrap_or_else(|| vec![]) == Bytes::from_json(&s["code"]), "code is incorrect");
 					fail_unless(state.balance(&address) == xjson!(&s["balance"]), "balance is incorrect");
 					fail_unless(state.nonce(&address) == xjson!(&s["nonce"]), "nonce is incorrect");
 					BTreeMap::from_json(&s["storage"]).iter().foreach(|(k, v)| fail_unless(&state.storage_at(&address, &k) == v, "storage is incorrect"));
@ -266,7 +266,7 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 	}


-	for f in failed.iter() {
+	for f in &failed {
 		println!("FAILED: {:?}", f);
 	}

--- a/src/tests/state.rs
+++ b/src/tests/state.rs
@ -15,7 +15,7 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 		let mut fail = false;
 		{
 			let mut fail_unless = |cond: bool| if !cond && !fail {
-				failed.push(name.to_string());
+				failed.push(name.clone());
 				flush(format!("FAIL\n"));
 				fail = true;
 				true
--- a/src/tests/test_common.rs
+++ b/src/tests/test_common.rs
@ -6,7 +6,7 @@ macro_rules! declare_test {
 		#[test]
 		#[allow(non_snake_case)]
 		fn $id() {
-			assert!(do_json_test(include_bytes!(concat!("../../res/ethereum/tests/", $name, ".json"))).len() == 0);
+			assert!(do_json_test(include_bytes!(concat!("../../res/ethereum/tests/", $name, ".json"))).is_empty());
 		}
 	};
 }
@ -18,7 +18,7 @@ macro_rules! declare_test_ignore {
 		#[ignore]
 		#[allow(non_snake_case)]
 		fn $id() {
-			assert!(do_json_test(include_bytes!(concat!("../../res/ethereum/tests/", $name, ".json"))).len() == 0);
+			assert!(do_json_test(include_bytes!(concat!("../../res/ethereum/tests/", $name, ".json"))).is_empty());
 		}
 	};
 }
--- a/src/tests/transaction.rs
+++ b/src/tests/transaction.rs
@ -9,13 +9,13 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 	let ot = RefCell::new(Transaction::new());
 	for (name, test) in json.as_object().unwrap() {
 		let mut fail = false;
-		let mut fail_unless = |cond: bool| if !cond && !fail { failed.push(name.to_string()); println!("Transaction: {:?}", ot.borrow()); fail = true };
+		let mut fail_unless = |cond: bool| if !cond && !fail { failed.push(name.clone()); println!("Transaction: {:?}", ot.borrow()); fail = true };
 		let schedule = match test.find("blocknumber")
 			.and_then(|j| j.as_string())
 			.and_then(|s| BlockNumber::from_str(s).ok())
 			.unwrap_or(0) { x if x < 900000 => &old_schedule, _ => &new_schedule };
 		let rlp = Bytes::from_json(&test["rlp"]);
-		let res = UntrustedRlp::new(&rlp).as_val().map_err(|e| From::from(e)).and_then(|t: Transaction| t.validate(schedule, schedule.have_delegate_call));
+		let res = UntrustedRlp::new(&rlp).as_val().map_err(From::from).and_then(|t: Transaction| t.validate(schedule, schedule.have_delegate_call));
 		fail_unless(test.find("transaction").is_none() == res.is_err());
 		if let (Some(&Json::Object(ref tx)), Some(&Json::String(ref expect_sender))) = (test.find("transaction"), test.find("sender")) {
 			let t = res.unwrap();
@ -30,11 +30,11 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 				fail_unless(to == &xjson!(&tx["to"]));
 			} else {
 				*ot.borrow_mut() = t.clone();
-				fail_unless(Bytes::from_json(&tx["to"]).len() == 0);
+				fail_unless(Bytes::from_json(&tx["to"]).is_empty());
 			}
 		}
 	}
-	for f in failed.iter() {
+	for f in &failed {
 		println!("FAILED: {:?}", f);
 	}
 	failed
--- a/src/transaction.rs
+++ b/src/transaction.rs
@ -117,9 +117,8 @@ impl Transaction {
 		};
 		s.append(&self.value);
 		s.append(&self.data);
-		match with_seal {
-			Seal::With => { s.append(&(self.v as u16)).append(&self.r).append(&self.s); },
-			_ => {}
+		if let Seal::With = with_seal {
+			s.append(&(self.v as u16)).append(&self.r).append(&self.s);
 		}
 	}

@ -138,7 +137,7 @@ impl FromJson for Transaction {
 			gas_price: xjson!(&json["gasPrice"]),
 			gas: xjson!(&json["gasLimit"]),
 			action: match Bytes::from_json(&json["to"]) {
-				ref x if x.len() == 0 => Action::Create,
+				ref x if x.is_empty() => Action::Create,
 				ref x => Action::Call(Address::from_slice(x)),
 			},
 			value: xjson!(&json["value"]),
@ -303,4 +302,4 @@ fn signing() {
 	let key = KeyPair::create().unwrap();
 	let t = Transaction::new_create(U256::from(42u64), b"Hello!".to_vec(), U256::from(3000u64), U256::from(50_000u64), U256::from(1u64)).signed(&key.secret());
 	assert_eq!(Address::from(key.public().sha3()), t.sender().unwrap());
-}
+}
--- a/src/verification.rs
+++ b/src/verification.rs
@ -64,7 +64,7 @@ pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine) ->
 /// Phase 3 verification. Check block information against parent and uncles.
 pub fn verify_block_family<BC>(header: &Header, bytes: &[u8], engine: &Engine, bc: &BC) -> Result<(), Error> where BC: BlockProvider {
 	// TODO: verify timestamp
-	let parent = try!(bc.block_header(&header.parent_hash).ok_or::<Error>(From::from(BlockError::UnknownParent(header.parent_hash.clone()))));
+	let parent = try!(bc.block_header(&header.parent_hash).ok_or_else(|| Error::from(BlockError::UnknownParent(header.parent_hash.clone()))));
 	try!(verify_parent(&header, &parent));
 	try!(engine.verify_block_family(&header, &parent, Some(bytes)));

@ -122,7 +122,7 @@ pub fn verify_block_family<BC>(header: &Header, bytes: &[u8], engine: &Engine, b
 			// cB.p^7	-------------/
 			// cB.p^8
 			let mut expected_uncle_parent = header.parent_hash.clone();
-			let uncle_parent = try!(bc.block_header(&uncle.parent_hash).ok_or::<Error>(From::from(BlockError::UnknownUncleParent(uncle.parent_hash.clone()))));
+			let uncle_parent = try!(bc.block_header(&uncle.parent_hash).ok_or_else(|| Error::from(BlockError::UnknownUncleParent(uncle.parent_hash.clone()))));
 			for _ in 0..depth {
 				match bc.block_details(&expected_uncle_parent) {
 					Some(details) => { 
@ -284,7 +284,7 @@ mod tests {

 		/// Get raw block data
 		fn block(&self, hash: &H256) -> Option<Bytes> {
-			self.blocks.get(hash).map(|b| b.clone())
+			self.blocks.get(hash).cloned()
 		}

 		/// Get the familial details concerning a block.
@ -302,7 +302,7 @@ mod tests {

 		/// Get the hash of given block's number.
 		fn block_hash(&self, index: BlockNumber) -> Option<H256> {
-			self.numbers.get(&index).map(|h| h.clone())
+			self.numbers.get(&index).cloned()
 		}
 	}

--- a/src/views.rs
+++ b/src/views.rs
@ -141,7 +141,7 @@ impl<'a> BlockView<'a> {

 	/// Return List of transactions in given block.
 	pub fn transaction_views(&self) -> Vec<TransactionView> {
-		self.rlp.at(1).iter().map(|rlp| TransactionView::new_from_rlp(rlp)).collect()
+		self.rlp.at(1).iter().map(TransactionView::new_from_rlp).collect()
 	}

 	/// Return transaction hashes.
@ -156,7 +156,7 @@ impl<'a> BlockView<'a> {

 	/// Return List of transactions in given block.
 	pub fn uncle_views(&self) -> Vec<HeaderView> {
-		self.rlp.at(2).iter().map(|rlp| HeaderView::new_from_rlp(rlp)).collect()
+		self.rlp.at(2).iter().map(HeaderView::new_from_rlp).collect()
 	}

 	/// Return list of uncle hashes of given block.
--- a/util/Cargo.toml
+++ b/util/Cargo.toml
@ -24,6 +24,7 @@ heapsize = "0.2"
 itertools = "0.4"
 slab = { git = "https://github.com/arkpar/slab.git" }
 sha3 = { path = "sha3" }
+clippy = "*" # Always newest, since we use nightly

 [dev-dependencies]
 json-tests = { path = "json-tests" }
--- a/util/src/bytes.rs
+++ b/util/src/bytes.rs
@ -106,18 +106,18 @@ 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
 		}
 	}
 }
@ -299,7 +299,7 @@ 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())
 	}
 }

--- a/util/src/chainfilter.rs
+++ b/util/src/chainfilter.rs
@ -323,10 +323,9 @@ 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
--- a/util/src/hash.rs
+++ b/util/src/hash.rs
@ -207,11 +207,11 @@ 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(),
@ -221,7 +221,7 @@ 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(())
@ -229,11 +229,11 @@ 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(())
@ -291,36 +291,36 @@ 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
 			}
 		}
@ -440,9 +440,9 @@ 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_else(|_| $from::new())
 				} else {
-					$from::from_str(clean_0x(s)).unwrap_or($from::new())
+					$from::from_str(clean_0x(s)).unwrap_or_else(|_| $from::new())
 				}
 			}
 		}
@ -565,6 +565,7 @@ mod tests {
 	use std::str::FromStr;

 	#[test]
+	#[allow(eq_op)]
 	fn hash() {
 		let h = H64([0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef]);
 		assert_eq!(H64::from_str("0123456789abcdef").unwrap(), h);
--- 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);
 				}
 			}
--- a/util/src/journaldb.rs
+++ b/util/src/journaldb.rs
@ -96,7 +96,7 @@ impl JournalDB {
 			})) {
 				let rlp = Rlp::new(&rlp_data);
 				let to_remove: Vec<H256> = rlp.val_at(if canon_id == rlp.val_at(0) {2} else {1});
-				for i in to_remove.iter() {
+				for i in &to_remove {
 					self.forward.remove(i);
 				}
 				try!(self.backing.delete(&last));
--- a/util/src/json_aid.rs
+++ b/util/src/json_aid.rs
@ -11,18 +11,18 @@ pub fn clean(s: &str) -> &str {

 fn u256_from_str(s: &str) -> U256 {
 	if s.len() >= 2 && &s[0..2] == "0x" {
-		U256::from_str(&s[2..]).unwrap_or(U256::from(0))
+		U256::from_str(&s[2..]).unwrap_or_else(|_| U256::zero())
 	} else {
-		U256::from_dec_str(s).unwrap_or(U256::from(0))
+		U256::from_dec_str(s).unwrap_or_else(|_| U256::zero())
 	}
 }

 impl FromJson for Bytes {
 	fn from_json(json: &Json) -> Self {
-		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![]),
+		match *json {
+			Json::String(ref s) => match s.len() % 2 {
+				0 => FromHex::from_hex(clean(s)).unwrap_or_else(|_| vec![]),
+				_ => FromHex::from_hex(&("0".to_owned() + &(clean(s).to_owned()))[..]).unwrap_or_else(|_| vec![]),
 			},
 			_ => vec![],
 		}
@ -31,8 +31,8 @@ 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(),
 		}
 	}
@ -40,8 +40,8 @@ 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(),
 		}
 	}
@ -49,9 +49,9 @@ 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)),
 		}
 	}
@ -135,4 +135,4 @@ fn option_types() {
 	assert_eq!(None, v);
 	let v: Option<u16> = xjson!(&j["empty"]);
 	assert_eq!(None, v);
-}
+}
--- a/util/src/lib.rs
+++ b/util/src/lib.rs
@ -2,6 +2,9 @@
 #![feature(op_assign_traits)]
 #![feature(augmented_assignments)]
 #![feature(associated_consts)]
+#![feature(plugin)]
+#![plugin(clippy)]
+#![allow(needless_range_loop, match_bool)]
 //! Ethcore-util library
 //!
 //! ### Rust version:
--- a/util/src/misc.rs
+++ b/util/src/misc.rs
@ -18,13 +18,13 @@ 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)]
--- 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)
 			},
--- 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);
--- 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"); }
--- 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);
 				}
 			}
--- 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)),
--- 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,
--- a/util/src/overlaydb.rs
+++ b/util/src/overlaydb.rs
@ -169,7 +169,7 @@ 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;
@ -194,16 +194,11 @@ 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,
--- 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);

--- a/util/src/rlp/rlptraits.rs
+++ b/util/src/rlp/rlptraits.rs
@ -9,7 +9,7 @@ pub trait Decoder: Sized {
 	/// TODO [arkpar] Please document me
 	fn as_list(&self) -> Result<Vec<Self>, DecoderError>;
 	/// TODO [Gav Wood] Please document me
-	fn as_rlp<'a>(&'a self) -> &'a UntrustedRlp<'a>;
+	fn as_rlp(&self) -> &UntrustedRlp;
 	/// TODO [debris] Please document me
 	fn as_raw(&self) -> &[u8];
 }
@ -255,7 +255,7 @@ 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.
 	///
@ -270,7 +270,7 @@ 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;
--- a/util/src/rlp/tests.rs
+++ b/util/src/rlp/tests.rs
@ -15,25 +15,25 @@ fn rlp_at() {
 		assert!(rlp.is_list());
 		//let animals = <Vec<String> as rlp::Decodable>::decode_untrusted(&rlp).unwrap();
 		let animals: Vec<String> = rlp.as_val().unwrap();
-		assert_eq!(animals, vec!["cat".to_string(), "dog".to_string()]);
+		assert_eq!(animals, vec!["cat".to_owned(), "dog".to_owned()]);

 		let cat = rlp.at(0).unwrap();
 		assert!(cat.is_data());
 		assert_eq!(cat.as_raw(), &[0x83, b'c', b'a', b't']);
-		//assert_eq!(String::decode_untrusted(&cat).unwrap(), "cat".to_string());
-		assert_eq!(cat.as_val::<String>().unwrap(), "cat".to_string());
+		//assert_eq!(String::decode_untrusted(&cat).unwrap(), "cat".to_owned());
+		assert_eq!(cat.as_val::<String>().unwrap(), "cat".to_owned());

 		let dog = rlp.at(1).unwrap();
 		assert!(dog.is_data());
 		assert_eq!(dog.as_raw(), &[0x83, b'd', b'o', b'g']);
-		//assert_eq!(String::decode_untrusted(&dog).unwrap(), "dog".to_string());
-		assert_eq!(dog.as_val::<String>().unwrap(), "dog".to_string());
+		//assert_eq!(String::decode_untrusted(&dog).unwrap(), "dog".to_owned());
+		assert_eq!(dog.as_val::<String>().unwrap(), "dog".to_owned());

 		let cat_again = rlp.at(0).unwrap();
 		assert!(cat_again.is_data());
 		assert_eq!(cat_again.as_raw(), &[0x83, b'c', b'a', b't']);
-		//assert_eq!(String::decode_untrusted(&cat_again).unwrap(), "cat".to_string());
-		assert_eq!(cat_again.as_val::<String>().unwrap(), "cat".to_string());
+		//assert_eq!(String::decode_untrusted(&cat_again).unwrap(), "cat".to_owned());
+		assert_eq!(cat_again.as_val::<String>().unwrap(), "cat".to_owned());
 	}
 }

@ -268,13 +268,13 @@ fn decode_untrusted_u256() {

 #[test]
 fn decode_untrusted_str() {
-	let tests = vec![DTestPair("cat".to_string(), vec![0x83, b'c', b'a', b't']),
-					 DTestPair("dog".to_string(), vec![0x83, b'd', b'o', b'g']),
-					 DTestPair("Marek".to_string(),
+	let tests = vec![DTestPair("cat".to_owned(), vec![0x83, b'c', b'a', b't']),
+					 DTestPair("dog".to_owned(), vec![0x83, b'd', b'o', b'g']),
+					 DTestPair("Marek".to_owned(),
 							   vec![0x85, b'M', b'a', b'r', b'e', b'k']),
-					 DTestPair("".to_string(), vec![0x80]),
+					 DTestPair("".to_owned(), vec![0x80]),
 					 DTestPair("Lorem ipsum dolor sit amet, consectetur adipisicing elit"
-								   .to_string(),
+								   .to_owned(),
 							   vec![0xb8, 0x38, b'L', b'o', b'r', b'e', b'm', b' ', b'i',
 									b'p', b's', b'u', b'm', b' ', b'd', b'o', b'l', b'o',
 									b'r', b' ', b's', b'i', b't', b' ', b'a', b'm', b'e',
@ -311,14 +311,14 @@ fn decode_untrusted_vector_u64() {

 #[test]
 fn decode_untrusted_vector_str() {
-	let tests = vec![DTestPair(vec!["cat".to_string(), "dog".to_string()],
+	let tests = vec![DTestPair(vec!["cat".to_owned(), "dog".to_owned()],
 							   vec![0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o', b'g'])];
 	run_decode_tests(tests);
 }

 #[test]
 fn decode_untrusted_vector_of_vectors_str() {
-	let tests = vec![DTestPair(vec![vec!["cat".to_string()]],
+	let tests = vec![DTestPair(vec![vec!["cat".to_owned()]],
 							   vec![0xc5, 0xc4, 0x83, b'c', b'a', b't'])];
 	run_decode_tests(tests);
 }
--- a/util/src/rlp/untrusted_rlp.rs
+++ b/util/src/rlp/untrusted_rlp.rs
@ -288,7 +288,7 @@ 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),
@ -324,7 +324,7 @@ 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
@ -355,12 +355,12 @@ 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
 	}
 }
@ -405,6 +405,7 @@ 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());

--- a/util/src/squeeze.rs
+++ b/util/src/squeeze.rs
@ -42,7 +42,7 @@ 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
 		}
 		
@ -50,7 +50,7 @@ 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);
--- a/util/src/trie/triedb.rs
+++ b/util/src/trie/triedb.rs
@ -38,6 +38,7 @@ 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
@ -103,7 +104,7 @@ 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) },
 			_ => {},
 		}
 	}
@ -141,12 +142,9 @@ 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]) {
--- a/util/src/trie/triedbmut.rs
+++ b/util/src/trie/triedbmut.rs
@ -50,6 +50,7 @@ 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.
@ -145,7 +146,7 @@ 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) },
 			_ => {},
 		}
 	}
@ -178,12 +179,9 @@ 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]) {
@ -331,6 +329,7 @@ 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.
@ -694,7 +693,7 @@ mod tests {
 		}
 	}

-	fn populate_trie<'db>(db: &'db mut HashDB, root: &'db mut H256, v: &Vec<(Vec<u8>, Vec<u8>)>) -> TrieDBMut<'db> {
+	fn populate_trie<'db>(db: &'db mut HashDB, root: &'db mut H256, v: &[(Vec<u8>, Vec<u8>)]) -> TrieDBMut<'db> {
 		let mut t = TrieDBMut::new(db, root);
 		for i in 0..v.len() {
 			let key: &[u8]= &v[i].0;
@ -704,8 +703,8 @@ mod tests {
 		t
 	}

-	fn unpopulate_trie<'a, 'db>(t: &mut TrieDBMut<'db>, v: &Vec<(Vec<u8>, Vec<u8>)>) {
-		for i in v.iter() {
+	fn unpopulate_trie<'db>(t: &mut TrieDBMut<'db>, v: &[(Vec<u8>, Vec<u8>)]) {
+		for i in v {
 			let key: &[u8]= &i.0;
 			t.remove(&key);
 		}
@ -761,7 +760,7 @@ mod tests {
 				println!("TRIE MISMATCH");
 				println!("");
 				println!("{:?} vs {:?}", memtrie.root(), real);
-				for i in x.iter() {
+				for i in &x {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie);
@ -774,7 +773,7 @@ mod tests {
 				println!("");
 				println!("remaining: {:?}", memtrie.db_items_remaining());
 				println!("{:?} vs {:?}", memtrie.root(), real);
-				for i in x.iter() {
+				for i in &x {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie);
@ -1051,12 +1050,12 @@ mod tests {
 				println!("TRIE MISMATCH");
 				println!("");
 				println!("ORIGINAL... {:?}", memtrie.root());
-				for i in x.iter() {
+				for i in &x {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie);
 				println!("SORTED... {:?}", memtrie_sorted.root());
-				for i in y.iter() {
+				for i in &y {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie_sorted);
--- a/util/src/uint.rs
+++ b/util/src/uint.rs
@ -200,7 +200,7 @@ 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]) {
@ -446,16 +446,16 @@ 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())
+							FromStr::from_str(&s[2..]).unwrap_or_else(|_| Default::default())
 						} else {
-							Uint::from_dec_str(s).unwrap_or(Default::default())
+							Uint::from_dec_str(s).unwrap_or_else(|_| 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(),
 				}
 			}
@ -488,7 +488,7 @@ 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);
 				}
 				$name(ret)
 			}
@ -500,7 +500,7 @@ macro_rules! construct_uint {
 			fn from_str(value: &str) -> Result<$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;
@ -1061,6 +1061,7 @@ mod tests {
 	}

 	#[test]
+	#[allow(eq_op)]
 	pub fn uint256_comp_test() {
 		let small = U256([10u64, 0, 0, 0]);
 		let big = U256([0x8C8C3EE70C644118u64, 0x0209E7378231E632, 0, 0]);