diff --git a/ethcore/src/engines/authority_round/mod.rs b/ethcore/src/engines/authority_round/mod.rs
index 2f4352b89..237f787f3 100644
--- a/ethcore/src/engines/authority_round/mod.rs
+++ b/ethcore/src/engines/authority_round/mod.rs
@@ -580,7 +580,7 @@ impl Engine for AuthorityRound {
 			warn!("Encountered error on closing block: {}", e);
 		}
 		match res {
-			Ok(res) => match *fields.tracing_enabled {
+			Ok(_) => match *fields.tracing_enabled {
 				true => Ok(CloseOutcome{trace: Some(tracer.traces())}),
 				false => Ok(CloseOutcome{trace: None})
 			},
diff --git a/ethcore/src/engines/tendermint/mod.rs b/ethcore/src/engines/tendermint/mod.rs
index b25b82d76..492a2c7a8 100644
--- a/ethcore/src/engines/tendermint/mod.rs
+++ b/ethcore/src/engines/tendermint/mod.rs
@@ -561,7 +561,7 @@ impl Engine for Tendermint {
 			warn!("Encountered error on closing block: {}", e);
 		}
 		match res {
-			Ok(res) => match *fields.tracing_enabled {
+			Ok(_) => match *fields.tracing_enabled {
 				true => Ok(CloseOutcome{trace: Some(tracer.traces())}),
 				false => Ok(CloseOutcome{trace: None})
 			},
diff --git a/ethcore/src/ethereum/ethash.rs b/ethcore/src/ethereum/ethash.rs
index a38f112fe..bc06fb408 100644
--- a/ethcore/src/ethereum/ethash.rs
+++ b/ethcore/src/ethereum/ethash.rs
@@ -308,7 +308,7 @@ impl Engine for Arc<Ethash> {
 		let current_number = fields.header.number();
 		for u in fields.uncles.iter() {
 			let uncle_miner = u.author().clone();
-			let mut result_uncle_reward: U256 = U256::from(0);
+			let result_uncle_reward: U256;
 
 			if eras == 0 {
 				result_uncle_reward = reward * U256::from(8 + u.number() - current_number) / U256::from(8);
diff --git a/ethcore/src/trace/noop_tracer.rs b/ethcore/src/trace/noop_tracer.rs
index 091d69547..0d8af7006 100644
--- a/ethcore/src/trace/noop_tracer.rs
+++ b/ethcore/src/trace/noop_tracer.rs
@@ -58,7 +58,7 @@ impl Tracer for NoopTracer {
 	fn trace_suicide(&mut self, _address: Address, _balance: U256, _refund_address: Address) {
 	}
 
-	fn trace_reward(&mut self, miner: Address, value: U256, reward_type: RewardType) {
+	fn trace_reward(&mut self, _: Address, _: U256, _: RewardType) {
 	}
 
 	fn subtracer(&self) -> Self {