diff --git a/account_manager/src/wallet/list.rs b/account_manager/src/wallet/list.rs
index 5b671b1dc..9190de391 100644
--- a/account_manager/src/wallet/list.rs
+++ b/account_manager/src/wallet/list.rs
@@ -10,7 +10,7 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
 }
 
 pub fn cli_run(wallet_base_dir: PathBuf) -> Result<(), String> {
-    let mgr = WalletManager::open(&wallet_base_dir)
+    let mgr = WalletManager::open(wallet_base_dir)
         .map_err(|e| format!("Unable to open --{}: {:?}", WALLETS_DIR_FLAG, e))?;
 
     for (name, _uuid) in mgr
diff --git a/beacon_node/beacon_chain/src/naive_aggregation_pool.rs b/beacon_node/beacon_chain/src/naive_aggregation_pool.rs
index 252e9915d..7eeb9bb56 100644
--- a/beacon_node/beacon_chain/src/naive_aggregation_pool.rs
+++ b/beacon_node/beacon_chain/src/naive_aggregation_pool.rs
@@ -402,7 +402,7 @@ impl<T: AggregateMap> NaiveAggregationPool<T> {
 
     /// Returns the total number of items stored in `self`.
     pub fn num_items(&self) -> usize {
-        self.maps.iter().map(|(_, map)| map.len()).sum()
+        self.maps.values().map(T::len).sum()
     }
 
     /// Returns an aggregated `T::Value` with the given `T::Data`, if any.
@@ -448,11 +448,7 @@ impl<T: AggregateMap> NaiveAggregationPool<T> {
         // If we have too many maps, remove the lowest amount to ensure we only have
         // `SLOTS_RETAINED` left.
         if self.maps.len() > SLOTS_RETAINED {
-            let mut slots = self
-                .maps
-                .iter()
-                .map(|(slot, _map)| *slot)
-                .collect::<Vec<_>>();
+            let mut slots = self.maps.keys().copied().collect::<Vec<_>>();
             // Sort is generally pretty slow, however `SLOTS_RETAINED` is quite low so it should be
             // negligible.
             slots.sort_unstable();
diff --git a/beacon_node/beacon_chain/src/test_utils.rs b/beacon_node/beacon_chain/src/test_utils.rs
index d6e8787f4..9183583fb 100644
--- a/beacon_node/beacon_chain/src/test_utils.rs
+++ b/beacon_node/beacon_chain/src/test_utils.rs
@@ -1459,7 +1459,7 @@ where
         let proposer_index = state.get_beacon_proposer_index(slot, &self.spec).unwrap();
 
         let signed_block = block.sign(
-            &self.validator_keypairs[proposer_index as usize].sk,
+            &self.validator_keypairs[proposer_index].sk,
             &state.fork(),
             state.genesis_validators_root(),
             &self.spec,
diff --git a/beacon_node/beacon_chain/src/validator_monitor.rs b/beacon_node/beacon_chain/src/validator_monitor.rs
index 2d093ff88..e95394bb7 100644
--- a/beacon_node/beacon_chain/src/validator_monitor.rs
+++ b/beacon_node/beacon_chain/src/validator_monitor.rs
@@ -631,10 +631,7 @@ impl<T: EthSpec> ValidatorMonitor<T> {
 
     // Return the `id`'s of all monitored validators.
     pub fn get_all_monitored_validators(&self) -> Vec<String> {
-        self.validators
-            .iter()
-            .map(|(_, val)| val.id.clone())
-            .collect()
+        self.validators.values().map(|val| val.id.clone()).collect()
     }
 
     /// If `self.auto_register == true`, add the `validator_index` to `self.monitored_validators`.
diff --git a/beacon_node/eth1/src/deposit_cache.rs b/beacon_node/eth1/src/deposit_cache.rs
index ab07b380d..75391e58a 100644
--- a/beacon_node/eth1/src/deposit_cache.rs
+++ b/beacon_node/eth1/src/deposit_cache.rs
@@ -675,7 +675,7 @@ pub mod tests {
     #[test]
     fn test_finalization_boundaries() {
         let n = 8;
-        let half = (n / 2) as usize;
+        let half = n / 2;
 
         let mut deposit_cache = get_cache_with_deposits(n as u64);
 
@@ -828,9 +828,9 @@ pub mod tests {
         // get_log(half+quarter) should return log with index `half+quarter`
         assert_eq!(
             q3_log_before_finalization.index,
-            (half + quarter) as u64,
+            half + quarter,
             "log index should be {}",
-            (half + quarter),
+            half + quarter,
         );
 
         // get lower quarter of deposits with max deposit count
diff --git a/beacon_node/execution_layer/src/engine_api/auth.rs b/beacon_node/execution_layer/src/engine_api/auth.rs
index 8fcdb2543..2f4c0cd1e 100644
--- a/beacon_node/execution_layer/src/engine_api/auth.rs
+++ b/beacon_node/execution_layer/src/engine_api/auth.rs
@@ -27,7 +27,7 @@ impl From<jsonwebtoken::errors::Error> for Error {
 /// Provides wrapper around `[u8; JWT_SECRET_LENGTH]` that implements `Zeroize`.
 #[derive(Zeroize, Clone)]
 #[zeroize(drop)]
-pub struct JwtKey([u8; JWT_SECRET_LENGTH as usize]);
+pub struct JwtKey([u8; JWT_SECRET_LENGTH]);
 
 impl JwtKey {
     /// Wrap given slice in `Self`. Returns an error if slice.len() != `JWT_SECRET_LENGTH`.
diff --git a/beacon_node/http_api/src/lib.rs b/beacon_node/http_api/src/lib.rs
index b018f9c73..6cfdaf5db 100644
--- a/beacon_node/http_api/src/lib.rs
+++ b/beacon_node/http_api/src/lib.rs
@@ -2840,7 +2840,7 @@ pub fn serve<T: BeaconChainTypes>(
                             let is_live =
                                 chain.validator_seen_at_epoch(index as usize, request_data.epoch);
                             api_types::LivenessResponseData {
-                                index: index as u64,
+                                index,
                                 epoch: request_data.epoch,
                                 is_live,
                             }
@@ -2876,7 +2876,7 @@ pub fn serve<T: BeaconChainTypes>(
         .and_then(
             |sysinfo, app_start: std::time::Instant, data_dir, network_globals| {
                 blocking_json_task(move || {
-                    let app_uptime = app_start.elapsed().as_secs() as u64;
+                    let app_uptime = app_start.elapsed().as_secs();
                     Ok(api_types::GenericResponse::from(observe_system_health_bn(
                         sysinfo,
                         data_dir,
diff --git a/beacon_node/lighthouse_network/src/peer_manager/peerdb/score.rs b/beacon_node/lighthouse_network/src/peer_manager/peerdb/score.rs
index fca665db9..bafa355d6 100644
--- a/beacon_node/lighthouse_network/src/peer_manager/peerdb/score.rs
+++ b/beacon_node/lighthouse_network/src/peer_manager/peerdb/score.rs
@@ -186,14 +186,7 @@ impl RealScore {
 
     /// Add an f64 to the score abiding by the limits.
     fn add(&mut self, score: f64) {
-        let mut new_score = self.lighthouse_score + score;
-        if new_score > MAX_SCORE {
-            new_score = MAX_SCORE;
-        }
-        if new_score < MIN_SCORE {
-            new_score = MIN_SCORE;
-        }
-
+        let new_score = (self.lighthouse_score + score).clamp(MIN_SCORE, MAX_SCORE);
         self.set_lighthouse_score(new_score);
     }
 
diff --git a/beacon_node/lighthouse_network/src/rpc/codec/ssz_snappy.rs b/beacon_node/lighthouse_network/src/rpc/codec/ssz_snappy.rs
index a4dd602b3..eccbf0dd6 100644
--- a/beacon_node/lighthouse_network/src/rpc/codec/ssz_snappy.rs
+++ b/beacon_node/lighthouse_network/src/rpc/codec/ssz_snappy.rs
@@ -443,7 +443,7 @@ fn handle_length(
         // Note: length-prefix of > 10 bytes(uint64) would be a decoding error
         match uvi_codec.decode(bytes).map_err(RPCError::from)? {
             Some(length) => {
-                *len = Some(length as usize);
+                *len = Some(length);
                 Ok(Some(length))
             }
             None => Ok(None), // need more bytes to decode length
diff --git a/beacon_node/lighthouse_network/src/service/gossipsub_scoring_parameters.rs b/beacon_node/lighthouse_network/src/service/gossipsub_scoring_parameters.rs
index 71a3953ec..88becd686 100644
--- a/beacon_node/lighthouse_network/src/service/gossipsub_scoring_parameters.rs
+++ b/beacon_node/lighthouse_network/src/service/gossipsub_scoring_parameters.rs
@@ -270,11 +270,11 @@ impl<TSpec: EthSpec> PeerScoreSettings<TSpec> {
 
         let modulo_smaller = max(
             1,
-            smaller_committee_size / self.target_aggregators_per_committee as usize,
+            smaller_committee_size / self.target_aggregators_per_committee,
         );
         let modulo_larger = max(
             1,
-            (smaller_committee_size + 1) / self.target_aggregators_per_committee as usize,
+            (smaller_committee_size + 1) / self.target_aggregators_per_committee,
         );
 
         Ok((
diff --git a/beacon_node/lighthouse_network/src/service/utils.rs b/beacon_node/lighthouse_network/src/service/utils.rs
index 09a8d1a86..3f02e73c0 100644
--- a/beacon_node/lighthouse_network/src/service/utils.rs
+++ b/beacon_node/lighthouse_network/src/service/utils.rs
@@ -88,7 +88,7 @@ fn keypair_from_hex(hex_bytes: &str) -> error::Result<Keypair> {
         hex_bytes.to_string()
     };
 
-    hex::decode(&hex_bytes)
+    hex::decode(hex_bytes)
         .map_err(|e| format!("Failed to parse p2p secret key bytes: {:?}", e).into())
         .and_then(keypair_from_bytes)
 }
diff --git a/beacon_node/operation_pool/src/attestation.rs b/beacon_node/operation_pool/src/attestation.rs
index 4af4edc0e..fbbd5d7dd 100644
--- a/beacon_node/operation_pool/src/attestation.rs
+++ b/beacon_node/operation_pool/src/attestation.rs
@@ -49,7 +49,7 @@ impl<'a, T: EthSpec> AttMaxCover<'a, T> {
         let indices = get_attesting_indices::<T>(committee.committee, &fresh_validators).ok()?;
         let fresh_validators_rewards: HashMap<u64, u64> = indices
             .iter()
-            .map(|i| *i as u64)
+            .copied()
             .flat_map(|validator_index| {
                 let reward = base::get_base_reward(
                     state,
diff --git a/beacon_node/store/src/chunked_vector.rs b/beacon_node/store/src/chunked_vector.rs
index 25169b479..8c64d4bcc 100644
--- a/beacon_node/store/src/chunked_vector.rs
+++ b/beacon_node/store/src/chunked_vector.rs
@@ -801,7 +801,7 @@ mod test {
 
     fn needs_genesis_value_test_randao<F: Field<TestSpec>>(_: F) {
         let spec = &TestSpec::default_spec();
-        let max = TestSpec::slots_per_epoch() as u64 * (F::Length::to_u64() - 1);
+        let max = TestSpec::slots_per_epoch() * (F::Length::to_u64() - 1);
         for i in 0..max {
             assert!(
                 F::slot_needs_genesis_value(Slot::new(i), spec),
diff --git a/common/account_utils/src/validator_definitions.rs b/common/account_utils/src/validator_definitions.rs
index 66e3b7354..6ce2517fb 100644
--- a/common/account_utils/src/validator_definitions.rs
+++ b/common/account_utils/src/validator_definitions.rs
@@ -189,7 +189,7 @@ impl ValidatorDefinitions {
             .write(true)
             .read(true)
             .create_new(false)
-            .open(&config_path)
+            .open(config_path)
             .map_err(Error::UnableToOpenFile)?;
         serde_yaml::from_reader(file).map_err(Error::UnableToParseFile)
     }
diff --git a/common/validator_dir/src/builder.rs b/common/validator_dir/src/builder.rs
index 596c918b3..2b3f670c7 100644
--- a/common/validator_dir/src/builder.rs
+++ b/common/validator_dir/src/builder.rs
@@ -196,7 +196,7 @@ impl<'a> Builder<'a> {
                 if path.exists() {
                     return Err(Error::DepositDataAlreadyExists(path));
                 } else {
-                    let hex = format!("0x{}", hex::encode(&deposit_data));
+                    let hex = format!("0x{}", hex::encode(deposit_data));
                     File::options()
                         .write(true)
                         .read(true)
diff --git a/consensus/serde_utils/src/hex.rs b/consensus/serde_utils/src/hex.rs
index 1e6c02427..9a2cd65c7 100644
--- a/consensus/serde_utils/src/hex.rs
+++ b/consensus/serde_utils/src/hex.rs
@@ -63,15 +63,15 @@ mod test {
     #[test]
     fn encoding() {
         let bytes = vec![0, 255];
-        let hex = encode(&bytes);
+        let hex = encode(bytes);
         assert_eq!(hex.as_str(), "0x00ff");
 
         let bytes = vec![];
-        let hex = encode(&bytes);
+        let hex = encode(bytes);
         assert_eq!(hex.as_str(), "0x");
 
         let bytes = vec![1, 2, 3];
-        let hex = encode(&bytes);
+        let hex = encode(bytes);
         assert_eq!(hex.as_str(), "0x010203");
     }
 }
diff --git a/consensus/serde_utils/src/u64_hex_be.rs b/consensus/serde_utils/src/u64_hex_be.rs
index 6af8a7589..e3364a2d2 100644
--- a/consensus/serde_utils/src/u64_hex_be.rs
+++ b/consensus/serde_utils/src/u64_hex_be.rs
@@ -36,7 +36,7 @@ impl<'de> Visitor<'de> for QuantityVisitor {
         } else if stripped.starts_with('0') {
             Err(de::Error::custom("cannot have leading zero"))
         } else if stripped.len() % 2 != 0 {
-            hex::decode(&format!("0{}", stripped))
+            hex::decode(format!("0{}", stripped))
                 .map_err(|e| de::Error::custom(format!("invalid hex ({:?})", e)))
         } else {
             hex::decode(stripped).map_err(|e| de::Error::custom(format!("invalid hex ({:?})", e)))
diff --git a/consensus/state_processing/src/per_block_processing/altair/sync_committee.rs b/consensus/state_processing/src/per_block_processing/altair/sync_committee.rs
index 306e86714..a5dcd6e0b 100644
--- a/consensus/state_processing/src/per_block_processing/altair/sync_committee.rs
+++ b/consensus/state_processing/src/per_block_processing/altair/sync_committee.rs
@@ -52,10 +52,10 @@ pub fn process_sync_aggregate<T: EthSpec>(
         .zip(aggregate.sync_committee_bits.iter())
     {
         if participation_bit {
-            increase_balance(state, participant_index as usize, participant_reward)?;
+            increase_balance(state, participant_index, participant_reward)?;
             increase_balance(state, proposer_index as usize, proposer_reward)?;
         } else {
-            decrease_balance(state, participant_index as usize, participant_reward)?;
+            decrease_balance(state, participant_index, participant_reward)?;
         }
     }
 
diff --git a/consensus/state_processing/src/per_epoch_processing/altair/rewards_and_penalties.rs b/consensus/state_processing/src/per_epoch_processing/altair/rewards_and_penalties.rs
index ccebbcb3a..e2aa67a61 100644
--- a/consensus/state_processing/src/per_epoch_processing/altair/rewards_and_penalties.rs
+++ b/consensus/state_processing/src/per_epoch_processing/altair/rewards_and_penalties.rs
@@ -76,7 +76,7 @@ pub fn get_flag_index_deltas<T: EthSpec>(
         let base_reward = get_base_reward(state, index, base_reward_per_increment, spec)?;
         let mut delta = Delta::default();
 
-        if unslashed_participating_indices.contains(index as usize)? {
+        if unslashed_participating_indices.contains(index)? {
             if !state.is_in_inactivity_leak(previous_epoch, spec) {
                 let reward_numerator = base_reward
                     .safe_mul(weight)?
@@ -89,8 +89,8 @@ pub fn get_flag_index_deltas<T: EthSpec>(
             delta.penalize(base_reward.safe_mul(weight)?.safe_div(WEIGHT_DENOMINATOR)?)?;
         }
         deltas
-            .get_mut(index as usize)
-            .ok_or(Error::DeltaOutOfBounds(index as usize))?
+            .get_mut(index)
+            .ok_or(Error::DeltaOutOfBounds(index))?
             .combine(delta)?;
     }
     Ok(())
diff --git a/consensus/state_processing/src/per_epoch_processing/base/rewards_and_penalties.rs b/consensus/state_processing/src/per_epoch_processing/base/rewards_and_penalties.rs
index 87e4261e0..e7a4d9c4d 100644
--- a/consensus/state_processing/src/per_epoch_processing/base/rewards_and_penalties.rs
+++ b/consensus/state_processing/src/per_epoch_processing/base/rewards_and_penalties.rs
@@ -235,7 +235,7 @@ fn get_inclusion_delay_delta(
         let max_attester_reward = base_reward.safe_sub(proposer_reward)?;
         delta.reward(max_attester_reward.safe_div(inclusion_info.delay)?)?;
 
-        let proposer_index = inclusion_info.proposer_index as usize;
+        let proposer_index = inclusion_info.proposer_index;
         Ok((delta, Some((proposer_index, proposer_delta))))
     } else {
         Ok((Delta::default(), None))
diff --git a/consensus/types/src/beacon_state.rs b/consensus/types/src/beacon_state.rs
index 79625c12e..12d44741f 100644
--- a/consensus/types/src/beacon_state.rs
+++ b/consensus/types/src/beacon_state.rs
@@ -482,7 +482,7 @@ impl<T: EthSpec> BeaconState<T> {
     /// Spec v0.12.1
     pub fn get_committee_count_at_slot(&self, slot: Slot) -> Result<u64, Error> {
         let cache = self.committee_cache_at_slot(slot)?;
-        Ok(cache.committees_per_slot() as u64)
+        Ok(cache.committees_per_slot())
     }
 
     /// Compute the number of committees in an entire epoch.
diff --git a/consensus/types/src/beacon_state/committee_cache.rs b/consensus/types/src/beacon_state/committee_cache.rs
index 7a526acc5..03adaf3d4 100644
--- a/consensus/types/src/beacon_state/committee_cache.rs
+++ b/consensus/types/src/beacon_state/committee_cache.rs
@@ -144,7 +144,7 @@ impl CommitteeCache {
             self.committees_per_slot as usize,
             index as usize,
         );
-        let committee = self.compute_committee(committee_index as usize)?;
+        let committee = self.compute_committee(committee_index)?;
 
         Some(BeaconCommittee {
             slot,
diff --git a/consensus/types/src/beacon_state/tests.rs b/consensus/types/src/beacon_state/tests.rs
index 5898bfe21..abca10e37 100644
--- a/consensus/types/src/beacon_state/tests.rs
+++ b/consensus/types/src/beacon_state/tests.rs
@@ -344,12 +344,7 @@ mod committees {
 
         let cache_epoch = cache_epoch.into_epoch(state_epoch);
 
-        execute_committee_consistency_test(
-            new_head_state,
-            cache_epoch,
-            validator_count as usize,
-            spec,
-        );
+        execute_committee_consistency_test(new_head_state, cache_epoch, validator_count, spec);
     }
 
     async fn committee_consistency_test_suite<T: EthSpec>(cached_epoch: RelativeEpoch) {
@@ -361,18 +356,13 @@ mod committees {
             .mul(spec.target_committee_size)
             .add(1);
 
-        committee_consistency_test::<T>(validator_count as usize, Epoch::new(0), cached_epoch)
+        committee_consistency_test::<T>(validator_count, Epoch::new(0), cached_epoch).await;
+
+        committee_consistency_test::<T>(validator_count, T::genesis_epoch() + 4, cached_epoch)
             .await;
 
         committee_consistency_test::<T>(
-            validator_count as usize,
-            T::genesis_epoch() + 4,
-            cached_epoch,
-        )
-        .await;
-
-        committee_consistency_test::<T>(
-            validator_count as usize,
+            validator_count,
             T::genesis_epoch()
                 + (T::slots_per_historical_root() as u64)
                     .mul(T::slots_per_epoch())
diff --git a/consensus/types/src/preset.rs b/consensus/types/src/preset.rs
index 8ee38e46a..fc5aa8730 100644
--- a/consensus/types/src/preset.rs
+++ b/consensus/types/src/preset.rs
@@ -202,7 +202,7 @@ mod test {
     }
 
     fn preset_from_file<T: DeserializeOwned>(preset_name: &str, filename: &str) -> T {
-        let f = File::open(&presets_base_path().join(preset_name).join(filename))
+        let f = File::open(presets_base_path().join(preset_name).join(filename))
             .expect("preset file exists");
         serde_yaml::from_reader(f).unwrap()
     }
diff --git a/slasher/tests/attester_slashings.rs b/slasher/tests/attester_slashings.rs
index 5cf3fe6c2..40d9fa511 100644
--- a/slasher/tests/attester_slashings.rs
+++ b/slasher/tests/attester_slashings.rs
@@ -39,8 +39,8 @@ fn double_vote_multi_vals() {
 fn double_vote_some_vals() {
     let v1 = vec![0, 1, 2, 3, 4, 5, 6];
     let v2 = vec![0, 2, 4, 6];
-    let att1 = indexed_att(&v1, 0, 1, 0);
-    let att2 = indexed_att(&v2, 0, 1, 1);
+    let att1 = indexed_att(v1, 0, 1, 0);
+    let att2 = indexed_att(v2, 0, 1, 1);
     let slashings = hashset![att_slashing(&att1, &att2)];
     let attestations = vec![att1, att2];
     slasher_test_indiv(&attestations, &slashings, 1);
@@ -53,9 +53,9 @@ fn double_vote_some_vals_repeat() {
     let v1 = vec![0, 1, 2, 3, 4, 5, 6];
     let v2 = vec![0, 2, 4, 6];
     let v3 = vec![1, 3, 5];
-    let att1 = indexed_att(&v1, 0, 1, 0);
-    let att2 = indexed_att(&v2, 0, 1, 1);
-    let att3 = indexed_att(&v3, 0, 1, 0);
+    let att1 = indexed_att(v1, 0, 1, 0);
+    let att2 = indexed_att(v2, 0, 1, 1);
+    let att3 = indexed_att(v3, 0, 1, 0);
     let slashings = hashset![att_slashing(&att1, &att2)];
     let attestations = vec![att1, att2, att3];
     slasher_test_indiv(&attestations, &slashings, 1);
@@ -67,8 +67,8 @@ fn double_vote_some_vals_repeat() {
 fn no_double_vote_same_target() {
     let v1 = vec![0, 1, 2, 3, 4, 5, 6];
     let v2 = vec![0, 1, 2, 3, 4, 5, 7, 8];
-    let att1 = indexed_att(&v1, 0, 1, 0);
-    let att2 = indexed_att(&v2, 0, 1, 0);
+    let att1 = indexed_att(v1, 0, 1, 0);
+    let att2 = indexed_att(v2, 0, 1, 0);
     let attestations = vec![att1, att2];
     slasher_test_indiv(&attestations, &hashset! {}, 1);
     slasher_test_indiv(&attestations, &hashset! {}, 1000);
@@ -79,8 +79,8 @@ fn no_double_vote_same_target() {
 fn no_double_vote_distinct_vals() {
     let v1 = vec![0, 1, 2, 3];
     let v2 = vec![4, 5, 6, 7];
-    let att1 = indexed_att(&v1, 0, 1, 0);
-    let att2 = indexed_att(&v2, 0, 1, 1);
+    let att1 = indexed_att(v1, 0, 1, 0);
+    let att2 = indexed_att(v2, 0, 1, 1);
     let attestations = vec![att1, att2];
     slasher_test_indiv(&attestations, &hashset! {}, 1);
     slasher_test_indiv(&attestations, &hashset! {}, 1000);
@@ -89,7 +89,7 @@ fn no_double_vote_distinct_vals() {
 #[test]
 fn no_double_vote_repeated() {
     let v = vec![0, 1, 2, 3, 4];
-    let att1 = indexed_att(&v, 0, 1, 0);
+    let att1 = indexed_att(v, 0, 1, 0);
     let att2 = att1.clone();
     let attestations = vec![att1, att2];
     slasher_test_indiv(&attestations, &hashset! {}, 1);
diff --git a/testing/execution_engine_integration/src/nethermind.rs b/testing/execution_engine_integration/src/nethermind.rs
index f643fbd5f..740d87ab8 100644
--- a/testing/execution_engine_integration/src/nethermind.rs
+++ b/testing/execution_engine_integration/src/nethermind.rs
@@ -76,7 +76,7 @@ impl GenericExecutionEngine for NethermindEngine {
     fn init_datadir() -> TempDir {
         let datadir = TempDir::new().unwrap();
         let genesis_json_path = datadir.path().join("genesis.json");
-        let mut file = File::create(&genesis_json_path).unwrap();
+        let mut file = File::create(genesis_json_path).unwrap();
         let json = nethermind_genesis_json();
         serde_json::to_writer(&mut file, &json).unwrap();
         datadir
diff --git a/testing/node_test_rig/src/lib.rs b/testing/node_test_rig/src/lib.rs
index d0a4ef949..82a60cda2 100644
--- a/testing/node_test_rig/src/lib.rs
+++ b/testing/node_test_rig/src/lib.rs
@@ -231,7 +231,7 @@ impl<E: EthSpec> LocalExecutionNode<E> {
             .tempdir()
             .expect("should create temp directory for client datadir");
         let jwt_file_path = datadir.path().join("jwt.hex");
-        if let Err(e) = std::fs::write(&jwt_file_path, config.jwt_key.hex_string()) {
+        if let Err(e) = std::fs::write(jwt_file_path, config.jwt_key.hex_string()) {
             panic!("Failed to write jwt file {}", e);
         }
         Self {
diff --git a/validator_client/src/doppelganger_service.rs b/validator_client/src/doppelganger_service.rs
index e6934ed48..558b9e199 100644
--- a/validator_client/src/doppelganger_service.rs
+++ b/validator_client/src/doppelganger_service.rs
@@ -441,7 +441,7 @@ impl DoppelgangerService {
         }
 
         // Get a list of indices to provide to the BN API.
-        let indices_only = indices_map.iter().map(|(index, _)| *index).collect();
+        let indices_only = indices_map.keys().copied().collect();
 
         // Pull the liveness responses from the BN.
         let request_epoch = request_slot.epoch(E::slots_per_epoch());
@@ -971,16 +971,16 @@ mod test {
         LivenessResponses {
             current_epoch_responses: detection_indices
                 .iter()
-                .map(|i| LivenessResponseData {
-                    index: *i as u64,
+                .map(|&index| LivenessResponseData {
+                    index,
                     epoch: current_epoch,
                     is_live: false,
                 })
                 .collect(),
             previous_epoch_responses: detection_indices
                 .iter()
-                .map(|i| LivenessResponseData {
-                    index: *i as u64,
+                .map(|&index| LivenessResponseData {
+                    index,
                     epoch: current_epoch - 1,
                     is_live: false,
                 })
diff --git a/validator_client/src/http_api/mod.rs b/validator_client/src/http_api/mod.rs
index 600e7a4c6..b87bb0838 100644
--- a/validator_client/src/http_api/mod.rs
+++ b/validator_client/src/http_api/mod.rs
@@ -331,7 +331,7 @@ pub fn serve<T: 'static + SlotClock + Clone, E: EthSpec>(
         .and(signer.clone())
         .and_then(|sysinfo, app_start: std::time::Instant, val_dir, signer| {
             blocking_signed_json_task(signer, move || {
-                let app_uptime = app_start.elapsed().as_secs() as u64;
+                let app_uptime = app_start.elapsed().as_secs();
                 Ok(api_types::GenericResponse::from(observe_system_health_vc(
                     sysinfo, val_dir, app_uptime,
                 )))
diff --git a/validator_client/src/initialized_validators.rs b/validator_client/src/initialized_validators.rs
index e8fe6ff2f..d3f6b1eb6 100644
--- a/validator_client/src/initialized_validators.rs
+++ b/validator_client/src/initialized_validators.rs
@@ -472,7 +472,7 @@ impl InitializedValidators {
 
     /// Iterate through all voting public keys in `self` that should be used when querying for duties.
     pub fn iter_voting_pubkeys(&self) -> impl Iterator<Item = &PublicKeyBytes> {
-        self.validators.iter().map(|(pubkey, _)| pubkey)
+        self.validators.keys()
     }
 
     /// Returns the voting `Keypair` for a given voting `PublicKey`, if all are true:
diff --git a/validator_client/src/key_cache.rs b/validator_client/src/key_cache.rs
index 2088aa683..b7abaaed0 100644
--- a/validator_client/src/key_cache.rs
+++ b/validator_client/src/key_cache.rs
@@ -104,7 +104,7 @@ impl KeyCache {
         let file = File::options()
             .read(true)
             .create_new(false)
-            .open(&cache_path)
+            .open(cache_path)
             .map_err(Error::UnableToOpenFile)?;
         serde_json::from_reader(file).map_err(Error::UnableToParseFile)
     }