Fix clippy suggestions. (#179)

* Fix clippy errors.

* Cargo fmt.

* Enable clippy checks.

* Create if does not exist.

* Fix warnings and enable sccache for clippy.

* chmod +x

* Revert and ignore errors.

* Update cancel-workflow-action.

* Fixes.

* Clippy fixes.

* Fix compilation.

* Fix new clippy warnings.

* fmt --all

* Fix the rest.

* fmt --all

* Conditional.

* Bump smallvec.

* Use separate cache dir for clippy to prevent races.

* Remove unused imports in tests

* Remove "useless conversion"

* Move clippy to main worfklow to avoid clashes.

* Fix clippy error.

* Fix remaning clippy errors.

* cargo fmt --all

Co-authored-by: Hernando Castano <castano.ha@gmail.com>

bridges/relays/ethereum/src/ethereum_exchange.rs

@@ -100,7 +100,7 @@ impl SourceClient<EthereumToSubstrateExchange> for EthereumTransactionsSource {
 		eth_header_id: &EthereumHeaderId,
 		eth_tx: EthereumTransaction,
 	) -> Result<EthereumTransactionInclusionProof, Self::Error> {
-		const TRANSACTION_HAS_RAW_FIELD_PROOF: &'static str = "RPC level checks that transactions from Ethereum\
+		const TRANSACTION_HAS_RAW_FIELD_PROOF: &str = "RPC level checks that transactions from Ethereum\
 			node are having `raw` field; qed";
 
 		let eth_header = self.client.header_by_hash_with_transactions(eth_header_id.1).await?;

bridges/relays/ethereum/src/ethereum_sync_loop.rs

@@ -163,7 +163,7 @@ impl TargetClient<EthereumHeadersSyncPipeline> for SubstrateHeadersTarget {
 		&self,
 		headers: Vec<QueuedEthereumHeader>,
 	) -> SubmittedHeaders<EthereumHeaderId, Self::Error> {
-		let (sign_params, sign_transactions) = (self.sign_params.clone(), self.sign_transactions.clone());
+		let (sign_params, sign_transactions) = (self.sign_params.clone(), self.sign_transactions);
 		self.client
 			.submit_ethereum_headers(sign_params, headers, sign_transactions)
 			.await
@@ -173,6 +173,7 @@ impl TargetClient<EthereumHeadersSyncPipeline> for SubstrateHeadersTarget {
 		Ok(HashSet::new())
 	}
 
+	#[allow(clippy::unit_arg)]
 	async fn complete_header(&self, id: EthereumHeaderId, _completion: ()) -> Result<EthereumHeaderId, Self::Error> {
 		Ok(id)
 	}

bridges/relays/ethereum/src/ethereum_types.rs

@@ -22,11 +22,11 @@ pub use web3::types::{Address, Bytes, CallRequest, H256, U128, U256, U64};
 
 /// When header is just received from the Ethereum node, we check that it has
 /// both number and hash fields filled.
-pub const HEADER_ID_PROOF: &'static str = "checked on retrieval; qed";
+pub const HEADER_ID_PROOF: &str = "checked on retrieval; qed";
 
 /// When receipt is just received from the Ethereum node, we check that it has
 /// gas_used field filled.
-pub const RECEIPT_GAS_USED_PROOF: &'static str = "checked on retrieval; qed";
+pub const RECEIPT_GAS_USED_PROOF: &str = "checked on retrieval; qed";
 
 /// Ethereum transaction hash type.
 pub type TransactionHash = H256;

bridges/relays/ethereum/src/exchange.rs

@@ -323,7 +323,7 @@ mod tests {
 			&self,
 			_: &TestTransactionHash,
 		) -> Result<Option<(TestHeaderId, TestTransaction)>, TestError> {
-			self.data.lock().transaction.clone()
+			self.data.lock().transaction
 		}
 
 		async fn transaction_proof(
@@ -331,7 +331,7 @@ mod tests {
 			_: &TestHeaderId,
 			_: TestTransaction,
 		) -> Result<TestTransactionProof, TestError> {
-			self.data.lock().transaction_proof.clone()
+			self.data.lock().transaction_proof
 		}
 	}
 
@@ -368,11 +368,11 @@ mod tests {
 		}
 
 		async fn is_header_known(&self, _: &TestHeaderId) -> Result<bool, TestError> {
-			self.data.lock().is_header_known.clone()
+			self.data.lock().is_header_known
 		}
 
 		async fn is_header_finalized(&self, _: &TestHeaderId) -> Result<bool, TestError> {
-			self.data.lock().is_header_finalized.clone()
+			self.data.lock().is_header_finalized
 		}
 
 		async fn submit_transaction_proof(&self, proof: TestTransactionProof) -> Result<(), TestError> {

bridges/relays/ethereum/src/headers.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
-use crate::sync_types::{HeaderId, HeaderStatus, HeadersSyncPipeline, QueuedHeader, SourceHeader};
+use crate::sync_types::{HeaderId, HeaderIdOf, HeaderStatus, HeadersSyncPipeline, QueuedHeader, SourceHeader};
 use linked_hash_map::LinkedHashMap;
 use num_traits::{One, Zero};
 use std::{
@@ -59,9 +59,9 @@ pub struct QueuedHeaders<P: HeadersSyncPipeline> {
 	known_headers: KnownHeaders<P>,
 	/// Headers that are waiting for completion data from source node. Mapped (and auto-sorted
 	/// by) to the last fetch time.
-	incomplete_headers: LinkedHashMap<HeaderId<P::Hash, P::Number>, Option<Instant>>,
+	incomplete_headers: LinkedHashMap<HeaderIdOf<P>, Option<Instant>>,
 	/// Headers that are waiting to be completed at target node. Auto-sorted by insertion time.
-	completion_data: LinkedHashMap<HeaderId<P::Hash, P::Number>, P::Completion>,
+	completion_data: LinkedHashMap<HeaderIdOf<P>, P::Completion>,
 	/// Best synced block number.
 	best_synced_number: P::Number,
 	/// Pruned blocks border. We do not store or accept any blocks with number less than
@@ -106,7 +106,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	/// Returns number of headers that are currently in given queue.
 	pub fn headers_in_status(&self, status: HeaderStatus) -> usize {
 		match status {
-			HeaderStatus::Unknown | HeaderStatus::Synced => return 0,
+			HeaderStatus::Unknown | HeaderStatus::Synced => 0,
 			HeaderStatus::MaybeOrphan => self
 				.maybe_orphan
 				.values()
@@ -168,7 +168,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Returns synchronization status of the header.
-	pub fn status(&self, id: &HeaderId<P::Hash, P::Number>) -> HeaderStatus {
+	pub fn status(&self, id: &HeaderIdOf<P>) -> HeaderStatus {
 		self.known_headers
 			.get(&id.0)
 			.and_then(|x| x.get(&id.1))
@@ -179,7 +179,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	/// Get oldest header from given queue.
 	pub fn header(&self, status: HeaderStatus) -> Option<&QueuedHeader<P>> {
 		match status {
-			HeaderStatus::Unknown | HeaderStatus::Synced => return None,
+			HeaderStatus::Unknown | HeaderStatus::Synced => None,
 			HeaderStatus::MaybeOrphan => oldest_header(&self.maybe_orphan),
 			HeaderStatus::Orphan => oldest_header(&self.orphan),
 			HeaderStatus::MaybeExtra => oldest_header(&self.maybe_extra),
@@ -197,7 +197,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 		f: impl FnMut(&QueuedHeader<P>) -> bool,
 	) -> Option<Vec<&QueuedHeader<P>>> {
 		match status {
-			HeaderStatus::Unknown | HeaderStatus::Synced => return None,
+			HeaderStatus::Unknown | HeaderStatus::Synced => None,
 			HeaderStatus::MaybeOrphan => oldest_headers(&self.maybe_orphan, f),
 			HeaderStatus::Orphan => oldest_headers(&self.orphan, f),
 			HeaderStatus::MaybeExtra => oldest_headers(&self.maybe_extra, f),
@@ -268,12 +268,12 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Receive best header from the target node.
-	pub fn target_best_header_response(&mut self, id: &HeaderId<P::Hash, P::Number>) {
+	pub fn target_best_header_response(&mut self, id: &HeaderIdOf<P>) {
 		self.header_synced(id)
 	}
 
 	/// Receive target node response for MaybeOrphan request.
-	pub fn maybe_orphan_response(&mut self, id: &HeaderId<P::Hash, P::Number>, response: bool) {
+	pub fn maybe_orphan_response(&mut self, id: &HeaderIdOf<P>, response: bool) {
 		if !response {
 			move_header_descendants::<P>(
 				&mut [&mut self.maybe_orphan],
@@ -295,7 +295,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Receive target node response for MaybeExtra request.
-	pub fn maybe_extra_response(&mut self, id: &HeaderId<P::Hash, P::Number>, response: bool) {
+	pub fn maybe_extra_response(&mut self, id: &HeaderIdOf<P>, response: bool) {
 		let (destination_status, destination_queue) = if response {
 			(HeaderStatus::Extra, &mut self.extra)
 		} else if self.is_parent_incomplete(id) {
@@ -315,7 +315,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Receive extra from source node.
-	pub fn extra_response(&mut self, id: &HeaderId<P::Hash, P::Number>, extra: P::Extra) {
+	pub fn extra_response(&mut self, id: &HeaderIdOf<P>, extra: P::Extra) {
 		let (destination_status, destination_queue) = if self.is_parent_incomplete(id) {
 			(HeaderStatus::Incomplete, &mut self.incomplete)
 		} else {
@@ -334,7 +334,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Receive completion response from source node.
-	pub fn completion_response(&mut self, id: &HeaderId<P::Hash, P::Number>, completion: Option<P::Completion>) {
+	pub fn completion_response(&mut self, id: &HeaderIdOf<P>, completion: Option<P::Completion>) {
 		let completion = match completion {
 			Some(completion) => completion,
 			None => {
@@ -361,12 +361,12 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 				id,
 			);
 
-			self.completion_data.insert(id.clone(), completion);
+			self.completion_data.insert(*id, completion);
 		}
 	}
 
 	/// When header is submitted to target node.
-	pub fn headers_submitted(&mut self, ids: Vec<HeaderId<P::Hash, P::Number>>) {
+	pub fn headers_submitted(&mut self, ids: Vec<HeaderIdOf<P>>) {
 		for id in ids {
 			move_header(
 				&mut self.ready,
@@ -380,7 +380,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// When header completion data is sent to target node.
-	pub fn header_completed(&mut self, id: &HeaderId<P::Hash, P::Number>) {
+	pub fn header_completed(&mut self, id: &HeaderIdOf<P>) {
 		if self.completion_data.remove(id).is_some() {
 			log::debug!(
 				target: "bridge",
@@ -404,7 +404,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Marks given headers incomplete.
-	pub fn add_incomplete_headers(&mut self, new_incomplete_headers: Vec<HeaderId<P::Hash, P::Number>>) {
+	pub fn add_incomplete_headers(&mut self, new_incomplete_headers: Vec<HeaderIdOf<P>>) {
 		for new_incomplete_header in new_incomplete_headers {
 			self.header_synced(&new_incomplete_header);
 			move_header_descendants::<P>(
@@ -426,7 +426,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// When incomplete headers ids are receved from target node.
-	pub fn incomplete_headers_response(&mut self, ids: HashSet<HeaderId<P::Hash, P::Number>>) {
+	pub fn incomplete_headers_response(&mut self, ids: HashSet<HeaderIdOf<P>>) {
 		// all new incomplete headers are marked Synced and all their descendants
 		// are moved from Ready/Submitted to Incomplete queue
 		let new_incomplete_headers = ids
@@ -466,7 +466,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Returns id of the header for which we want to fetch completion data.
-	pub fn incomplete_header(&mut self) -> Option<HeaderId<P::Hash, P::Number>> {
+	pub fn incomplete_header(&mut self) -> Option<HeaderIdOf<P>> {
 		queued_incomplete_header(&mut self.incomplete_headers, |last_fetch_time| {
 			let retry = match *last_fetch_time {
 				Some(last_fetch_time) => last_fetch_time.elapsed() > RETRY_FETCH_COMPLETION_INTERVAL,
@@ -483,7 +483,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// Returns header completion data to upload to target node.
-	pub fn header_to_complete(&mut self) -> Option<(HeaderId<P::Hash, P::Number>, &P::Completion)> {
+	pub fn header_to_complete(&mut self) -> Option<(HeaderIdOf<P>, &P::Completion)> {
 		queued_incomplete_header(&mut self.completion_data, |_| true)
 	}
 
@@ -520,7 +520,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 
 	/// Returns true if parent of this header is either incomplete or waiting for
 	/// its own incomplete ancestor to be completed.
-	fn is_parent_incomplete(&self, id: &HeaderId<P::Hash, P::Number>) -> bool {
+	fn is_parent_incomplete(&self, id: &HeaderIdOf<P>) -> bool {
 		let status = self.status(id);
 		let header = match status {
 			HeaderStatus::MaybeOrphan => header(&self.maybe_orphan, id),
@@ -546,7 +546,7 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 	}
 
 	/// When we receive new Synced header from target node.
-	fn header_synced(&mut self, id: &HeaderId<P::Hash, P::Number>) {
+	fn header_synced(&mut self, id: &HeaderIdOf<P>) {
 		// update best synced block number
 		self.best_synced_number = std::cmp::max(self.best_synced_number, id.0);
 
@@ -593,19 +593,12 @@ impl<P: HeadersSyncPipeline> QueuedHeaders<P> {
 }
 
 /// Insert header to the queue.
-fn insert_header<P: HeadersSyncPipeline>(
-	queue: &mut HeadersQueue<P>,
-	id: HeaderId<P::Hash, P::Number>,
-	header: QueuedHeader<P>,
-) {
+fn insert_header<P: HeadersSyncPipeline>(queue: &mut HeadersQueue<P>, id: HeaderIdOf<P>, header: QueuedHeader<P>) {
 	queue.entry(id.0).or_default().insert(id.1, header);
 }
 
 /// Remove header from the queue.
-fn remove_header<P: HeadersSyncPipeline>(
-	queue: &mut HeadersQueue<P>,
-	id: &HeaderId<P::Hash, P::Number>,
-) -> Option<QueuedHeader<P>> {
+fn remove_header<P: HeadersSyncPipeline>(queue: &mut HeadersQueue<P>, id: &HeaderIdOf<P>) -> Option<QueuedHeader<P>> {
 	let mut headers_at = match queue.entry(id.0) {
 		BTreeMapEntry::Occupied(headers_at) => headers_at,
 		BTreeMapEntry::Vacant(_) => return None,
@@ -619,10 +612,7 @@ fn remove_header<P: HeadersSyncPipeline>(
 }
 
 /// Get header from the queue.
-fn header<'a, P: HeadersSyncPipeline>(
-	queue: &'a HeadersQueue<P>,
-	id: &HeaderId<P::Hash, P::Number>,
-) -> Option<&'a QueuedHeader<P>> {
+fn header<'a, P: HeadersSyncPipeline>(queue: &'a HeadersQueue<P>, id: &HeaderIdOf<P>) -> Option<&'a QueuedHeader<P>> {
 	queue.get(&id.0).and_then(|by_hash| by_hash.get(&id.1))
 }
 
@@ -634,9 +624,9 @@ fn move_header<P: HeadersSyncPipeline>(
 	destination_queue: &mut HeadersQueue<P>,
 	known_headers: &mut KnownHeaders<P>,
 	destination_status: HeaderStatus,
-	id: &HeaderId<P::Hash, P::Number>,
+	id: &HeaderIdOf<P>,
 	prepare: impl FnOnce(QueuedHeader<P>) -> QueuedHeader<P>,
-) -> Option<HeaderId<P::Hash, P::Number>> {
+) -> Option<HeaderIdOf<P>> {
 	let header = match remove_header(source_queue, id) {
 		Some(header) => prepare(header),
 		None => return None,
@@ -655,7 +645,7 @@ fn move_header_descendants<P: HeadersSyncPipeline>(
 	destination_queue: &mut HeadersQueue<P>,
 	known_headers: &mut KnownHeaders<P>,
 	destination_status: HeaderStatus,
-	id: &HeaderId<P::Hash, P::Number>,
+	id: &HeaderIdOf<P>,
 ) {
 	let mut current_number = id.0 + One::one();
 	let mut current_parents = HashSet::new();
@@ -743,7 +733,7 @@ fn prune_known_headers<P: HeadersSyncPipeline>(known_headers: &mut KnownHeaders<
 /// Change header status.
 fn set_header_status<P: HeadersSyncPipeline>(
 	known_headers: &mut KnownHeaders<P>,
-	id: &HeaderId<P::Hash, P::Number>,
+	id: &HeaderIdOf<P>,
 	status: HeaderStatus,
 ) {
 	log::debug!(

bridges/relays/ethereum/src/main.rs

@@ -101,7 +101,6 @@ fn main() {
 		}
 		("", _) => {
 			log::error!(target: "bridge", "No subcommand specified");
-			return;
 		}
 		_ => unreachable!("all possible subcommands are checked above; qed"),
 	}

bridges/relays/ethereum/src/rpc_errors.rs

@@ -18,7 +18,6 @@ use crate::ethereum_types::{EthereumHeaderId, TransactionHash as EthereumTransac
 use crate::sync_types::MaybeConnectionError;
 
 use jsonrpsee::client::RequestError;
-use serde_json;
 
 /// Contains common errors that can occur when
 /// interacting with a Substrate or Ethereum node
@@ -79,10 +78,7 @@ impl From<ethabi::Error> for RpcError {
 
 impl MaybeConnectionError for RpcError {
 	fn is_connection_error(&self) -> bool {
-		match *self {
-			RpcError::Request(RequestError::TransportError(_)) => true,
-			_ => false,
-		}
+		matches!(*self, RpcError::Request(RequestError::TransportError(_)))
 	}
 }
 

bridges/relays/ethereum/src/substrate_client.rs

@@ -400,5 +400,5 @@ fn create_signed_transaction(
 	let signer: sp_runtime::MultiSigner = signer.public().into();
 	let (function, extra, _) = raw_payload.deconstruct();
 
-	bridge_node_runtime::UncheckedExtrinsic::new_signed(function, signer.into_account().into(), signature.into(), extra)
+	bridge_node_runtime::UncheckedExtrinsic::new_signed(function, signer.into_account(), signature.into(), extra)
 }

bridges/relays/ethereum/src/sync.rs

@@ -15,7 +15,7 @@
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
 use crate::headers::QueuedHeaders;
-use crate::sync_types::{HeaderId, HeaderStatus, HeadersSyncPipeline, QueuedHeader};
+use crate::sync_types::{HeaderIdOf, HeaderStatus, HeadersSyncPipeline, QueuedHeader};
 use num_traits::{One, Saturating, Zero};
 
 /// Common sync params.
@@ -56,7 +56,7 @@ pub struct HeadersSync<P: HeadersSyncPipeline> {
 	/// Best header number known to source node.
 	source_best_number: Option<P::Number>,
 	/// Best header known to target node.
-	target_best_header: Option<HeaderId<P::Hash, P::Number>>,
+	target_best_header: Option<HeaderIdOf<P>>,
 	/// Headers queue.
 	headers: QueuedHeaders<P>,
 }
@@ -78,7 +78,7 @@ impl<P: HeadersSyncPipeline> HeadersSync<P> {
 	}
 
 	/// Best header known to target node.
-	pub fn target_best_header(&self) -> Option<HeaderId<P::Hash, P::Number>> {
+	pub fn target_best_header(&self) -> Option<HeaderIdOf<P>> {
 		self.target_best_header
 	}
 
@@ -94,7 +94,7 @@ impl<P: HeadersSyncPipeline> HeadersSync<P> {
 	}
 
 	/// Returns synchronization status.
-	pub fn status(&self) -> (&Option<HeaderId<P::Hash, P::Number>>, &Option<P::Number>) {
+	pub fn status(&self) -> (&Option<HeaderIdOf<P>>, &Option<P::Number>) {
 		(&self.target_best_header, &self.source_best_number)
 	}
 
@@ -111,7 +111,7 @@ impl<P: HeadersSyncPipeline> HeadersSync<P> {
 	/// Select header that needs to be downloaded from the source node.
 	pub fn select_new_header_to_download(&self) -> Option<P::Number> {
 		// if we haven't received best header from source node yet, there's nothing we can download
-		let source_best_number = self.source_best_number.clone()?;
+		let source_best_number = self.source_best_number?;
 
 		// if we haven't received known best header from target node yet, there's nothing we can download
 		let target_best_header = self.target_best_header.as_ref()?;
@@ -205,7 +205,7 @@ impl<P: HeadersSyncPipeline> HeadersSync<P> {
 
 	/// Receive new best header from the target node.
 	/// Returns true if it is different from the previous block known to us.
-	pub fn target_best_header_response(&mut self, best_header: HeaderId<P::Hash, P::Number>) -> bool {
+	pub fn target_best_header_response(&mut self, best_header: HeaderIdOf<P>) -> bool {
 		log::debug!(
 			target: "bridge",
 			"Received best known header from {}: {:?}",
@@ -244,7 +244,7 @@ pub mod tests {
 	use super::*;
 	use crate::ethereum_types::{EthereumHeadersSyncPipeline, H256};
 	use crate::headers::tests::{header, id};
-	use crate::sync_types::HeaderStatus;
+	use crate::sync_types::{HeaderId, HeaderStatus};
 
 	fn side_hash(number: u64) -> H256 {
 		H256::from_low_u64_le(1000 + number)

bridges/relays/ethereum/src/sync_loop.rs

@@ -18,7 +18,7 @@ use crate::metrics::{start as metrics_start, GlobalMetrics, MetricsParams, Regis
 use crate::sync::HeadersSyncParams;
 use crate::sync_loop_metrics::SyncLoopMetrics;
 use crate::sync_types::{
-	HeaderId, HeaderStatus, HeadersSyncPipeline, MaybeConnectionError, QueuedHeader, SubmittedHeaders,
+	HeaderIdOf, HeaderStatus, HeadersSyncPipeline, MaybeConnectionError, QueuedHeader, SubmittedHeaders,
 };
 
 use async_trait::async_trait;
@@ -68,17 +68,15 @@ pub trait SourceClient<P: HeadersSyncPipeline>: Sized {
 	async fn header_by_number(&self, number: P::Number) -> Result<P::Header, Self::Error>;
 
 	/// Get completion data by header hash.
-	async fn header_completion(
-		&self,
-		id: HeaderId<P::Hash, P::Number>,
-	) -> Result<(HeaderId<P::Hash, P::Number>, Option<P::Completion>), Self::Error>;
+	async fn header_completion(&self, id: HeaderIdOf<P>)
+		-> Result<(HeaderIdOf<P>, Option<P::Completion>), Self::Error>;
 
 	/// Get extra data by header hash.
 	async fn header_extra(
 		&self,
-		id: HeaderId<P::Hash, P::Number>,
+		id: HeaderIdOf<P>,
 		header: QueuedHeader<P>,
-	) -> Result<(HeaderId<P::Hash, P::Number>, P::Extra), Self::Error>;
+	) -> Result<(HeaderIdOf<P>, P::Extra), Self::Error>;
 }
 
 /// Target client trait.
@@ -88,35 +86,23 @@ pub trait TargetClient<P: HeadersSyncPipeline>: Sized {
 	type Error: std::fmt::Debug + MaybeConnectionError;
 
 	/// Returns ID of best header known to the target node.
-	async fn best_header_id(&self) -> Result<HeaderId<P::Hash, P::Number>, Self::Error>;
+	async fn best_header_id(&self) -> Result<HeaderIdOf<P>, Self::Error>;
 
 	/// Returns true if header is known to the target node.
-	async fn is_known_header(
-		&self,
-		id: HeaderId<P::Hash, P::Number>,
-	) -> Result<(HeaderId<P::Hash, P::Number>, bool), Self::Error>;
+	async fn is_known_header(&self, id: HeaderIdOf<P>) -> Result<(HeaderIdOf<P>, bool), Self::Error>;
 
 	/// Submit headers.
-	async fn submit_headers(
-		&self,
-		headers: Vec<QueuedHeader<P>>,
-	) -> SubmittedHeaders<HeaderId<P::Hash, P::Number>, Self::Error>;
+	async fn submit_headers(&self, headers: Vec<QueuedHeader<P>>) -> SubmittedHeaders<HeaderIdOf<P>, Self::Error>;
 
 	/// Returns ID of headers that require to be 'completed' before children can be submitted.
-	async fn incomplete_headers_ids(&self) -> Result<HashSet<HeaderId<P::Hash, P::Number>>, Self::Error>;
+	async fn incomplete_headers_ids(&self) -> Result<HashSet<HeaderIdOf<P>>, Self::Error>;
 
 	/// Submit completion data for header.
-	async fn complete_header(
-		&self,
-		id: HeaderId<P::Hash, P::Number>,
-		completion: P::Completion,
-	) -> Result<HeaderId<P::Hash, P::Number>, Self::Error>;
+	async fn complete_header(&self, id: HeaderIdOf<P>, completion: P::Completion)
+		-> Result<HeaderIdOf<P>, Self::Error>;
 
 	/// Returns true if header requires extra data to be submitted.
-	async fn requires_extra(
-		&self,
-		header: QueuedHeader<P>,
-	) -> Result<(HeaderId<P::Hash, P::Number>, bool), Self::Error>;
+	async fn requires_extra(&self, header: QueuedHeader<P>) -> Result<(HeaderIdOf<P>, bool), Self::Error>;
 }
 
 /// Run headers synchronization.
@@ -327,7 +313,7 @@ pub fn run<P: HeadersSyncPipeline, TC: TargetClient<P>>(
 				},
 				submitted_headers = target_submit_header_future => {
 					// following line helps Rust understand the type of `submitted_headers` :/
-					let submitted_headers: SubmittedHeaders<HeaderId<P::Hash, P::Number>, TC::Error> = submitted_headers;
+					let submitted_headers: SubmittedHeaders<HeaderIdOf<P>, TC::Error> = submitted_headers;
 					let maybe_fatal_error = submitted_headers.fatal_error.map(Err).unwrap_or(Ok(()));
 
 					target_client_is_online = process_future_result(
@@ -380,7 +366,7 @@ pub fn run<P: HeadersSyncPipeline, TC: TargetClient<P>>(
 			// update metrics
 			if metrics_enabled {
 				metrics_global.update();
-				metrics_sync.update(&mut sync);
+				metrics_sync.update(&sync);
 			}
 
 			// print progress

bridges/relays/ethereum/src/sync_loop_metrics.rs

@@ -55,8 +55,8 @@ impl SyncLoopMetrics {
 	/// Update metrics.
 	pub fn update<P: HeadersSyncPipeline>(&mut self, sync: &HeadersSync<P>) {
 		let headers = sync.headers();
-		let source_best_number = sync.source_best_number().unwrap_or(Zero::zero());
-		let target_best_number = sync.target_best_header().map(|id| id.0).unwrap_or(Zero::zero());
+		let source_best_number = sync.source_best_number().unwrap_or_else(Zero::zero);
+		let target_best_number = sync.target_best_header().map(|id| id.0).unwrap_or_else(Zero::zero);
 
 		self.best_block_numbers
 			.with_label_values(&["source"])

bridges/relays/ethereum/src/sync_loop_tests.rs

@@ -408,7 +408,7 @@ fn run_backoff_test(result: Result<(), TestError>) -> (Duration, Duration) {
 		&mut backoff,
 		|_| {},
 		&mut go_offline_future,
-		|delay| async_std::task::sleep(delay),
+		async_std::task::sleep,
 		|| "Test error".into(),
 	);
 

bridges/relays/ethereum/src/sync_types.rs

@@ -95,6 +95,9 @@ pub trait HeadersSyncPipeline: Clone + Copy {
 	fn estimate_size(source: &QueuedHeader<Self>) -> usize;
 }
 
+/// A HeaderId for `HeaderSyncPipeline`.
+pub type HeaderIdOf<P> = HeaderId<<P as HeadersSyncPipeline>::Hash, <P as HeadersSyncPipeline>::Number>;
+
 /// Header that we're receiving from source node.
 pub trait SourceHeader<Hash, Number> {
 	/// Returns ID of header.

bridges/relays/substrate/src/bridge.rs

@@ -156,9 +156,10 @@ pub async fn run_async(params: Params, exit: Box<dyn Future<Output = ()> + Unpin
 	Ok(())
 }
 
-fn initial_next_events<'a>(
-	chains: &'a HashMap<ChainId, RefCell<Chain>>,
-) -> Vec<Pin<Box<dyn Future<Output = Result<(ChainId, RawClientEvent), Error>> + 'a>>> {
+type EventsResult = Result<(ChainId, RawClientEvent), Error>;
+type EventsFuture<'a> = Pin<Box<dyn Future<Output = EventsResult> + 'a>>;
+
+fn initial_next_events<'a>(chains: &'a HashMap<ChainId, RefCell<Chain>>) -> Vec<EventsFuture<'a>> {
 	chains
 		.values()
 		.map(|chain_cell| async move {
@@ -175,12 +176,9 @@ fn initial_next_events<'a>(
 }
 
 async fn next_event<'a>(
-	next_events: Vec<Pin<Box<dyn Future<Output = Result<(ChainId, RawClientEvent), Error>> + 'a>>>,
+	next_events: Vec<EventsFuture<'a>>,
 	chains: &'a HashMap<ChainId, RefCell<Chain>>,
-) -> (
-	Result<(Hash, RawClientEvent), Error>,
-	Vec<Pin<Box<dyn Future<Output = Result<(ChainId, RawClientEvent), Error>> + 'a>>>,
-) {
+) -> (Result<(Hash, RawClientEvent), Error>, Vec<EventsFuture<'a>>) {
 	let (result, _, mut rest) = future::select_all(next_events).await;
 
 	match result {