Update to 2018 edition idioms (#237)

* Update to 2018 edition idioms

* Reduce extern crate usage

* fix missing import in tests

* Add missing `use $crate::unroll`

* Address review comments

ethbloom/src/lib.rs

@@ -140,13 +140,13 @@ impl Bloom {
 	}
 
 	pub fn contains_bloom<'a, B>(&self, bloom: B) -> bool where BloomRef<'a>: From<B> {
-		let bloom_ref: BloomRef = bloom.into();
+		let bloom_ref: BloomRef<'_> = bloom.into();
 		// workaround for https://github.com/rust-lang/rust/issues/43644
 		self.contains_bloom_ref(bloom_ref)
 	}
 
-	fn contains_bloom_ref(&self, bloom: BloomRef) -> bool {
-		let self_ref: BloomRef = self.into();
+	fn contains_bloom_ref(&self, bloom: BloomRef<'_>) -> bool {
+		let self_ref: BloomRef<'_> = self.into();
 		self_ref.contains_bloom(bloom)
 	}
 
@@ -158,7 +158,7 @@ impl Bloom {
 		let mask = bloom_bits - 1;
 		let bloom_bytes = (log2(bloom_bits) + 7) / 8;
 
-		let hash: Hash = input.into();
+		let hash: Hash<'_> = input.into();
 
 		// must be a power of 2
 		assert_eq!(m & (m - 1), 0);
@@ -183,7 +183,7 @@ impl Bloom {
 	}
 
 	pub fn accrue_bloom<'a, B>(&mut self, bloom: B) where BloomRef<'a>: From<B> {
-		let bloom_ref: BloomRef = bloom.into();
+		let bloom_ref: BloomRef<'_> = bloom.into();
 		assert_eq!(self.0.len(), BLOOM_SIZE);
 		assert_eq!(bloom_ref.0.len(), BLOOM_SIZE);
 		for i in 0..BLOOM_SIZE {
@@ -213,7 +213,7 @@ impl<'a> BloomRef<'a> {
 
 	#[allow(clippy::trivially_copy_pass_by_ref)]
 	pub fn contains_bloom<'b, B>(&self, bloom: B) -> bool where BloomRef<'b>: From<B> {
-		let bloom_ref: BloomRef = bloom.into();
+		let bloom_ref: BloomRef<'_> = bloom.into();
 		assert_eq!(self.0.len(), BLOOM_SIZE);
 		assert_eq!(bloom_ref.0.len(), BLOOM_SIZE);
 		for i in 0..BLOOM_SIZE {

ethereum-types/src/lib.rs

@@ -1,7 +1,6 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg(feature = "std")]
-extern crate core;
+
 
 mod hash;
 mod uint;

kvdb-rocksdb/src/lib.rs

@@ -409,7 +409,7 @@ impl Database {
 	}
 
 	/// Commit buffered changes to database. Must be called under `flush_lock`
-	fn write_flushing_with_lock(&self, _lock: &mut MutexGuard<bool>) -> io::Result<()> {
+	fn write_flushing_with_lock(&self, _lock: &mut MutexGuard<'_, bool>) -> io::Result<()> {
 		match *self.db.read() {
 			Some(DBAndColumns { ref db, ref cfs }) => {
 				let batch = WriteBatch::new();
@@ -534,7 +534,7 @@ impl Database {
 	}
 
 	/// Get database iterator for flushed data.
-	pub fn iter(&self, col: Option<u32>) -> Option<DatabaseIterator> {
+	pub fn iter(&self, col: Option<u32>) -> Option<DatabaseIterator<'_>> {
 		match *self.db.read() {
 			Some(DBAndColumns { ref db, ref cfs }) => {
 				let overlay = &self.overlay.read()[Self::to_overlay_column(col)];
@@ -561,7 +561,7 @@ impl Database {
 		}
 	}
 
-	fn iter_from_prefix(&self, col: Option<u32>, prefix: &[u8]) -> Option<DatabaseIterator> {
+	fn iter_from_prefix(&self, col: Option<u32>, prefix: &[u8]) -> Option<DatabaseIterator<'_>> {
 		match *self.db.read() {
 			Some(DBAndColumns { ref db, ref cfs }) => {
 				let iter = col.map_or_else(|| db.iterator_opt(IteratorMode::From(prefix, Direction::Forward), &self.read_opts),
@@ -703,10 +703,8 @@ impl Drop for Database {
 
 #[cfg(test)]
 mod tests {
-	extern crate tempdir;
-
 	use std::str::FromStr;
-	use self::tempdir::TempDir;
+	use tempdir::TempDir;
 	use ethereum_types::H256;
 	use super::*;
 

kvdb-web/src/error.rs

@@ -45,7 +45,7 @@ impl std::error::Error for Error {
 }
 
 impl fmt::Display for Error {
-	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		match *self {
 			Error::WindowNotAvailable => write!(f, "Accessing a Window has failed"),
 			Error::NotSupported(ref err) => write!(

parity-bytes/src/lib.rs

@@ -32,7 +32,7 @@ use core::{cmp::min, fmt, ops};
 pub struct PrettySlice<'a>(&'a [u8]);
 
 impl<'a> fmt::Debug for PrettySlice<'a> {
-	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		for i in 0..self.0.len() {
 			if i > 0 {
 				write!(f, "·{:02x}", self.0[i])?;
@@ -45,7 +45,7 @@ impl<'a> fmt::Debug for PrettySlice<'a> {
 }
 
 impl<'a> fmt::Display for PrettySlice<'a> {
-	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		for i in 0..self.0.len() {
 			write!(f, "{:02x}", self.0[i])?;
 		}
@@ -57,15 +57,15 @@ impl<'a> fmt::Display for PrettySlice<'a> {
 /// defaults cannot otherwise be avoided.
 pub trait ToPretty {
 	/// Convert a type into a derivative form in order to make `format!` print it prettily.
-	fn pretty(&self) -> PrettySlice;
+	fn pretty(&self) -> PrettySlice<'_>;
 	/// Express the object as a hex string.
 	fn to_hex(&self) -> String {
 		format!("{}", self.pretty())
 	}
 }
 
 impl<T: AsRef<[u8]>> ToPretty for T {
-	fn pretty(&self) -> PrettySlice {
+	fn pretty(&self) -> PrettySlice<'_> {
 		PrettySlice(self.as_ref())
 	}
 }

parity-crypto/benches/bench.rs

@@ -14,9 +14,6 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-
-extern crate parity_crypto;
-
 #[macro_use]
 extern crate criterion;
 

parity-crypto/src/error.rs

@@ -43,7 +43,7 @@ enum PrivSymmErr {
 }
 
 impl StdError for Error {
-	fn source(&self) -> Option<&(StdError + 'static)> {
+	fn source(&self) -> Option<&(dyn StdError + 'static)> {
 		match self {
 			Error::Scrypt(scrypt_err) => Some(scrypt_err),
 			Error::Symm(symm_err) => Some(symm_err),
@@ -52,7 +52,7 @@ impl StdError for Error {
 }
 
 impl StdError for ScryptError {
-	fn source(&self) -> Option<&(StdError + 'static)> {
+	fn source(&self) -> Option<&(dyn StdError + 'static)> {
 		match self {
 			ScryptError::ScryptParam(err) => Some(err),
 			ScryptError::ScryptLength(err) => Some(err),
@@ -62,7 +62,7 @@ impl StdError for ScryptError {
 }
 
 impl StdError for SymmError {
-	fn source(&self) -> Option<&(StdError + 'static)> {
+	fn source(&self) -> Option<&(dyn StdError + 'static)> {
 		match &self.0 {
 			PrivSymmErr::BlockMode(err) => Some(err),
 			PrivSymmErr::InvalidKeyLength(err) => Some(err),
@@ -72,7 +72,7 @@ impl StdError for SymmError {
 }
 
 impl fmt::Display for Error {
-	fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> result::Result<(), fmt::Error> {
 		match self {
 			Error::Scrypt(err)=> write!(f, "scrypt error: {}", err),
 			Error::Symm(err) => write!(f, "symm error: {}", err),
@@ -81,7 +81,7 @@ impl fmt::Display for Error {
 }
 
 impl fmt::Display for ScryptError {
-	fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> result::Result<(), fmt::Error> {
 		match self {
 			ScryptError::InvalidN => write!(f, "invalid n argument"),
 			ScryptError::InvalidP => write!(f, "invalid p argument"),
@@ -92,7 +92,7 @@ impl fmt::Display for ScryptError {
 }
 
 impl fmt::Display for SymmError {
-	fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> result::Result<(), fmt::Error> {
 		match self {
 			SymmError(PrivSymmErr::BlockMode(err)) => write!(f, "block cipher error: {}", err),
 			SymmError(PrivSymmErr::KeyStream(err)) => write!(f, "ctr key stream ended: {}", err),

parity-crypto/src/hmac/mod.rs

@@ -52,7 +52,7 @@ pub struct SigKey<T>(KeyInner, PhantomData<T>);
 struct DisposableBox(Box<[u8]>);
 
 impl std::fmt::Debug for DisposableBox {
-	fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		write!(f, "{:?}", &self.0.as_ref())
 	}
 }

parity-crypto/src/pbkdf2/mod.rs

@@ -17,11 +17,11 @@
 pub struct Salt<'a>(pub &'a [u8]);
 pub struct Secret<'a>(pub &'a [u8]);
 
-pub fn sha256(iter: u32, salt: Salt, sec: Secret, out: &mut [u8; 32]) {
+pub fn sha256(iter: u32, salt: Salt<'_>, sec: Secret<'_>, out: &mut [u8; 32]) {
 	pbkdf2::pbkdf2::<hmac::Hmac<sha2::Sha256>>(sec.0, salt.0, iter as usize, out)
 }
 
-pub fn sha512(iter: u32, salt: Salt, sec: Secret, out: &mut [u8; 64]) {
+pub fn sha512(iter: u32, salt: Salt<'_>, sec: Secret<'_>, out: &mut [u8; 64]) {
 	pbkdf2::pbkdf2::<hmac::Hmac<sha2::Sha512>>(sec.0, salt.0, iter as usize, out)
 }
 

rlp/tests/tests.rs

@@ -509,7 +509,7 @@ fn test_nested_list_roundtrip() {
 	}
 
 	impl Decodable for Inner {
-		fn decode(rlp: &Rlp) -> Result<Self, DecoderError> {
+		fn decode(rlp: &Rlp<'_>) -> Result<Self, DecoderError> {
 			Ok(Inner(rlp.val_at(0)?, rlp.val_at(1)?))
 		}
 	}
@@ -526,7 +526,7 @@ fn test_nested_list_roundtrip() {
 	}
 
 	impl<T: Decodable> Decodable for Nest<T> {
-		fn decode(rlp: &Rlp) -> Result<Self, DecoderError> {
+		fn decode(rlp: &Rlp<'_>) -> Result<Self, DecoderError> {
 			Ok(Nest(rlp.list_at(0)?))
 		}
 	}

transaction-pool/src/error.rs

@@ -31,7 +31,7 @@ pub enum Error<Hash: fmt::Debug + fmt::LowerHex> {
 pub type Result<T, H> = result::Result<T, Error<H>>;
 
 impl<H: fmt::Debug + fmt::LowerHex> fmt::Display for Error<H> {
-	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		match self {
 			Error::AlreadyImported(h) =>
 				write!(f, "[{:?}] already imported", h),

transaction-pool/src/pool.rs

@@ -138,7 +138,7 @@ impl<T, S, L> Pool<T, S, L> where
 	/// new transaction via the supplied `ShouldReplace` implementation and may be evicted.
 	///
 	/// The `Listener` will be informed on any drops or rejections.
-	pub fn import(&mut self, transaction: T, replace: &ShouldReplace<T>) -> error::Result<Arc<T>, T::Hash> {
+	pub fn import(&mut self, transaction: T, replace: &dyn ShouldReplace<T>) -> error::Result<Arc<T>, T::Hash> {
 		let mem_usage = transaction.mem_usage();
 
 		if self.by_hash.contains_key(transaction.hash()) {
@@ -288,7 +288,7 @@ impl<T, S, L> Pool<T, S, L> where
 	///
 	/// Returns `None` in case we couldn't decide if the transaction should replace the worst transaction or not.
 	/// In such case we will accept the transaction even though it is going to exceed the limit.
-	fn remove_worst(&mut self, transaction: &Transaction<T>, replace: &ShouldReplace<T>) -> error::Result<Option<Transaction<T>>, T::Hash> {
+	fn remove_worst(&mut self, transaction: &Transaction<T>, replace: &dyn ShouldReplace<T>) -> error::Result<Option<Transaction<T>>, T::Hash> {
 		let to_remove = match self.worst_transactions.iter().next_back() {
 			// No elements to remove? and the pool is still full?
 			None => {
@@ -437,7 +437,7 @@ impl<T, S, L> Pool<T, S, L> where
 	}
 
 	/// Returns an iterator of pending (ready) transactions.
-	pub fn pending<R: Ready<T>>(&self, ready: R) -> PendingIterator<T, R, S, L> {
+	pub fn pending<R: Ready<T>>(&self, ready: R) -> PendingIterator<'_, T, R, S, L> {
 		PendingIterator {
 			ready,
 			best_transactions: self.best_transactions.clone(),
@@ -446,7 +446,7 @@ impl<T, S, L> Pool<T, S, L> where
 	}
 
 	/// Returns pending (ready) transactions from given sender.
-	pub fn pending_from_sender<R: Ready<T>>(&self, ready: R, sender: &T::Sender) -> PendingIterator<T, R, S, L> {
+	pub fn pending_from_sender<R: Ready<T>>(&self, ready: R, sender: &T::Sender) -> PendingIterator<'_, T, R, S, L> {
 		let best_transactions = self.transactions.get(sender)
 			.and_then(|transactions| transactions.worst_and_best())
 			.map(|(_, best)| ScoreWithRef::new(best.0, best.1))
@@ -465,7 +465,7 @@ impl<T, S, L> Pool<T, S, L> where
 	}
 
 	/// Returns unprioritized list of ready transactions.
-	pub fn unordered_pending<R: Ready<T>>(&self, ready: R) -> UnorderedIterator<T, R, S> {
+	pub fn unordered_pending<R: Ready<T>>(&self, ready: R) -> UnorderedIterator<'_, T, R, S> {
 		UnorderedIterator {
 			ready,
 			senders: self.transactions.iter(),

transaction-pool/src/replace.rs

@@ -51,5 +51,5 @@ pub trait ShouldReplace<T> {
     /// Decides if `new` should push out `old` transaction from the pool.
     ///
     /// NOTE returning `InsertNew` here can lead to some transactions being accepted above pool limits.
-    fn should_replace(&self, old: &ReplaceTransaction<T>, new: &ReplaceTransaction<T>) -> Choice;
+    fn should_replace(&self, old: &ReplaceTransaction<'_, T>, new: &ReplaceTransaction<'_, T>) -> Choice;
 }

transaction-pool/src/tests/helpers.rs

@@ -74,7 +74,7 @@ impl Scoring<Transaction> for DummyScoring {
 }
 
 impl ShouldReplace<Transaction> for DummyScoring {
-	fn should_replace(&self, old: &ReplaceTransaction<Transaction>, new: &ReplaceTransaction<Transaction>) -> scoring::Choice {
+	fn should_replace(&self, old: &ReplaceTransaction<'_, Transaction>, new: &ReplaceTransaction<'_, Transaction>) -> scoring::Choice {
 		if self.always_insert {
 			scoring::Choice::InsertNew
 		} else if new.gas_price > old.gas_price {

transaction-pool/src/tests/mod.rs

@@ -272,9 +272,9 @@ fn should_skip_staled_pending_transactions() {
 	let b = TransactionBuilder::default();
 	let mut txq = TestPool::default();
 
-	let tx0 = import(&mut txq, b.tx().nonce(0).gas_price(5).new()).unwrap();
+	let _tx0 = import(&mut txq, b.tx().nonce(0).gas_price(5).new()).unwrap();
 	let tx2 = import(&mut txq, b.tx().nonce(2).gas_price(5).new()).unwrap();
-	let tx1 = import(&mut txq, b.tx().nonce(1).gas_price(5).new()).unwrap();
+	let _tx1 = import(&mut txq, b.tx().nonce(1).gas_price(5).new()).unwrap();
 
 	// tx0 and tx1 are Stale, tx2 is Ready
 	let mut pending = txq.pending(NonceReady::new(2));

transaction-pool/src/transactions.rs

@@ -70,7 +70,7 @@ impl<T: fmt::Debug, S: Scoring<T>> Transactions<T, S> {
 		self.transactions.len()
 	}
 
-	pub fn iter(&self) -> ::std::slice::Iter<Transaction<T>> {
+	pub fn iter(&self) -> ::std::slice::Iter<'_, Transaction<T>> {
 		self.transactions.iter()
 	}
 

uint/benches/bigint.rs

@@ -12,13 +12,9 @@
 //! rustup run cargo bench
 //! ```
 
-#[macro_use]
-extern crate criterion;
-extern crate core;
-#[macro_use]
-extern crate uint;
-extern crate num_bigint;
-extern crate rug;
+
+use criterion::{criterion_group, criterion_main};
+use uint::{construct_uint, uint_full_mul_reg};
 
 construct_uint! {
 	pub struct U256(4);

uint/examples/modular.rs

@@ -6,8 +6,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#[cfg(feature="std")]
-extern crate core;
+
 
 #[macro_use]
 extern crate uint;

uint/src/lib.rs

@@ -11,21 +11,21 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #[doc(hidden)]
-pub extern crate byteorder;
+pub use byteorder;
 
 // Re-export libcore using an alias so that the macros can work without
 // requiring `extern crate core` downstream.
 #[doc(hidden)]
-pub extern crate core as core_;
+pub use core as core_;
 
 #[doc(hidden)]
-pub extern crate rustc_hex;
+pub use rustc_hex;
 
 #[cfg(feature="quickcheck")]
 #[doc(hidden)]
-pub extern crate quickcheck;
+pub use quickcheck;
 
-extern crate crunchy;
+#[doc(hidden)]
 pub use crunchy::unroll;
 
 #[macro_use]