diff --git a/sync/src/orphan_blocks_pool.rs b/sync/src/orphan_blocks_pool.rs
index 3dc95b21..ce8b3f7e 100644
--- a/sync/src/orphan_blocks_pool.rs
+++ b/sync/src/orphan_blocks_pool.rs
@@ -92,17 +92,19 @@ impl OrphanBlocksPool {
 		let parent_orphan_keys: Vec<_> = self.orphaned_blocks.keys().cloned().collect();
 		for parent_orphan_key in parent_orphan_keys {
 			if let Entry::Occupied(mut orphan_entry) = self.orphaned_blocks.entry(parent_orphan_key) {
-				if {
+				let remove_entry = {
 					let mut orphans = orphan_entry.get_mut();
 					let orphans_keys: HashSet<H256> = orphans.keys().cloned().collect();
-					for orphan_to_remove in orphans_keys.intersection(&hashes) {
+					for orphan_to_remove in orphans_keys.intersection(hashes) {
 						self.unknown_blocks.remove(orphan_to_remove);
 						removed.push((orphan_to_remove.clone(),
 							orphans.remove(orphan_to_remove).expect("iterating by intersection of orphans keys with hashes; removing from orphans; qed")
 						));
 					}
 					orphans.is_empty()
-				} {
+				};
+				
+				if remove_entry {
 					orphan_entry.remove_entry();
 				}
 			}
diff --git a/sync/src/synchronization_chain.rs b/sync/src/synchronization_chain.rs
index c9d0c0f5..4ef19907 100644
--- a/sync/src/synchronization_chain.rs
+++ b/sync/src/synchronization_chain.rs
@@ -549,7 +549,7 @@ impl Chain {
 		while let Some(hash) = queue.pop_front() {
 			let all_keys: Vec<_> = self.verifying_transactions.keys().cloned().collect();
 			for h in all_keys {
-				if {
+				let remove_verifying_transaction = {
 					if let Some(entry) = self.verifying_transactions.get(&h) {
 						if entry.inputs.iter().any(|i| i.previous_output.hash == hash) {
 							queue.push_back(h.clone());
@@ -561,7 +561,9 @@ impl Chain {
 						// iterating by previously read keys
 						unreachable!()
 					}
-				} {
+				};
+
+				if remove_verifying_transaction {
 					self.verifying_transactions.remove(&h);
 				}
 			}
diff --git a/sync/src/synchronization_client.rs b/sync/src/synchronization_client.rs
index da470606..601fbb89 100644
--- a/sync/src/synchronization_client.rs
+++ b/sync/src/synchronization_client.rs
@@ -350,7 +350,7 @@ impl<T> Client for SynchronizationClient<T> where T: TaskExecutor {
 		let unknown_transactions_hashes: Vec<_> = {
 			let chain = self.chain.read();
 			transactions_hashes.into_iter()
-				.filter(|h| chain.transaction_state(&h) == TransactionState::Unknown)
+				.filter(|h| chain.transaction_state(h) == TransactionState::Unknown)
 				.collect()
 		};
 
@@ -557,7 +557,7 @@ impl<T> Client for SynchronizationClient<T> where T: TaskExecutor {
 			let mut chain = self.chain.write();
 
 			// forget for this transaction and all its children
-			chain.forget_verifying_transaction_with_children(&hash);
+			chain.forget_verifying_transaction_with_children(hash);
 		}
 	}
 }
@@ -979,7 +979,7 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 			let peer_index = *block_entry.get();
 			// find a # of blocks, which this thread has supplied
 			if let Entry::Occupied(mut entry) = self.verifying_blocks_waiters.entry(peer_index) {
-				if {
+				let is_last_block = {
 					let &mut (ref mut waiting, ref waiter) = entry.get_mut();
 					waiting.remove(hash);
 					// if this is the last block => awake waiting threads
@@ -990,7 +990,9 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 						}
 					}
 					is_last_block
-				} {
+				};
+
+				if is_last_block {
 					entry.remove_entry();
 				}
 			}