diff --git a/Makefile b/Makefile
index 5d21625b6..d843e81cd 100644
--- a/Makefile
+++ b/Makefile
@@ -121,7 +121,11 @@ test-full: cargo-fmt test-release test-debug test-ef
 # Lints the code for bad style and potentially unsafe arithmetic using Clippy.
 # Clippy lints are opt-in per-crate for now. By default, everything is allowed except for performance and correctness lints.
 lint:
-	cargo clippy --all --tests -- -D warnings
+	cargo clippy --all --tests -- \
+        -D warnings \
+        -A clippy::from-over-into \
+        -A clippy::upper-case-acronyms \
+        -A clippy::vec-init-then-push
 
 # Runs the makefile in the `ef_tests` repo.
 #
diff --git a/account_manager/src/validator/exit.rs b/account_manager/src/validator/exit.rs
index 17eafc602..66fb21dd5 100644
--- a/account_manager/src/validator/exit.rs
+++ b/account_manager/src/validator/exit.rs
@@ -10,7 +10,7 @@ use eth2_keystore::Keystore;
 use eth2_network_config::Eth2NetworkConfig;
 use safe_arith::SafeArith;
 use slot_clock::{SlotClock, SystemTimeSlotClock};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::time::Duration;
 use tokio::time::sleep;
 use types::{ChainSpec, Epoch, EthSpec, Fork, VoluntaryExit};
@@ -91,7 +91,7 @@ pub fn cli_run<E: EthSpec>(matches: &ArgMatches, env: Environment<E>) -> Result<
 
 /// Gets the keypair and validator_index for every validator and calls `publish_voluntary_exit` on it.
 async fn publish_voluntary_exit<E: EthSpec>(
-    keystore_path: &PathBuf,
+    keystore_path: &Path,
     password_file_path: Option<&PathBuf>,
     client: &BeaconNodeHttpClient,
     spec: &ChainSpec,
@@ -310,7 +310,7 @@ fn get_current_epoch<E: EthSpec>(genesis_time: u64, spec: &ChainSpec) -> Option<
 /// If the `password_file_path` is Some, unlock keystore using password in given file
 /// otherwise, prompts user for a password to unlock the keystore.
 fn load_voting_keypair(
-    voting_keystore_path: &PathBuf,
+    voting_keystore_path: &Path,
     password_file_path: Option<&PathBuf>,
     stdin_inputs: bool,
 ) -> Result<Keypair, String> {
diff --git a/beacon_node/eth1/src/inner.rs b/beacon_node/eth1/src/inner.rs
index 718080a1e..f6c5e85ef 100644
--- a/beacon_node/eth1/src/inner.rs
+++ b/beacon_node/eth1/src/inner.rs
@@ -53,7 +53,7 @@ impl Inner {
     pub fn from_bytes(bytes: &[u8], config: Config, spec: ChainSpec) -> Result<Self, String> {
         let ssz_cache = SszEth1Cache::from_ssz_bytes(bytes)
             .map_err(|e| format!("Ssz decoding error: {:?}", e))?;
-        Ok(ssz_cache.to_inner(config, spec)?)
+        ssz_cache.to_inner(config, spec)
     }
 
     /// Returns a reference to the specification.
diff --git a/beacon_node/eth2_libp2p/src/behaviour/mod.rs b/beacon_node/eth2_libp2p/src/behaviour/mod.rs
index d998389a8..02468285a 100644
--- a/beacon_node/eth2_libp2p/src/behaviour/mod.rs
+++ b/beacon_node/eth2_libp2p/src/behaviour/mod.rs
@@ -36,7 +36,7 @@ use ssz::Encode;
 use std::collections::HashSet;
 use std::fs::File;
 use std::io::Write;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::{
     collections::VecDeque,
     marker::PhantomData,
@@ -1336,7 +1336,7 @@ impl<TSpec: EthSpec> std::convert::From<Response<TSpec>> for RPCCodedResponse<TS
 }
 
 /// Persist metadata to disk
-pub fn save_metadata_to_disk<E: EthSpec>(dir: &PathBuf, metadata: MetaData<E>, log: &slog::Logger) {
+pub fn save_metadata_to_disk<E: EthSpec>(dir: &Path, metadata: MetaData<E>, log: &slog::Logger) {
     let _ = std::fs::create_dir_all(&dir);
     match File::create(dir.join(METADATA_FILENAME))
         .and_then(|mut f| f.write_all(&metadata.as_ssz_bytes()))
diff --git a/beacon_node/eth2_libp2p/src/service.rs b/beacon_node/eth2_libp2p/src/service.rs
index e49344919..079338b54 100644
--- a/beacon_node/eth2_libp2p/src/service.rs
+++ b/beacon_node/eth2_libp2p/src/service.rs
@@ -474,7 +474,7 @@ fn strip_peer_id(addr: &mut Multiaddr) {
 
 /// Load metadata from persisted file. Return default metadata if loading fails.
 fn load_or_build_metadata<E: EthSpec>(
-    network_dir: &std::path::PathBuf,
+    network_dir: &std::path::Path,
     log: &slog::Logger,
 ) -> MetaData<E> {
     // Default metadata
diff --git a/beacon_node/src/config.rs b/beacon_node/src/config.rs
index d22811e39..256f7e04f 100644
--- a/beacon_node/src/config.rs
+++ b/beacon_node/src/config.rs
@@ -10,7 +10,7 @@ use std::cmp::max;
 use std::fs;
 use std::net::{IpAddr, Ipv4Addr, ToSocketAddrs};
 use std::net::{TcpListener, UdpSocket};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use types::{ChainSpec, Checkpoint, Epoch, EthSpec, Hash256, PublicKeyBytes, GRAFFITI_BYTES_LEN};
 
@@ -422,7 +422,7 @@ pub fn get_config<E: EthSpec>(
 pub fn set_network_config(
     config: &mut NetworkConfig,
     cli_args: &ArgMatches,
-    data_dir: &PathBuf,
+    data_dir: &Path,
     log: &Logger,
     use_listening_port_as_enr_port_by_default: bool,
 ) -> Result<(), String> {
diff --git a/beacon_node/store/src/hot_cold_store.rs b/beacon_node/store/src/hot_cold_store.rs
index ea456acb9..4105c393f 100644
--- a/beacon_node/store/src/hot_cold_store.rs
+++ b/beacon_node/store/src/hot_cold_store.rs
@@ -660,7 +660,7 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> HotColdDB<E, Hot, Cold>
         partial_state.load_historical_roots(&self.cold_db, &self.spec)?;
         partial_state.load_randao_mixes(&self.cold_db, &self.spec)?;
 
-        Ok(partial_state.try_into()?)
+        partial_state.try_into()
     }
 
     /// Load a restore point state by its `restore_point_index`.
diff --git a/common/deposit_contract/build.rs b/common/deposit_contract/build.rs
index 719a5a05f..ded9e9b78 100644
--- a/common/deposit_contract/build.rs
+++ b/common/deposit_contract/build.rs
@@ -35,7 +35,7 @@ fn testnet_url() -> String {
 fn main() {
     match get_all_contracts() {
         Ok(()) => (),
-        Err(e) => panic!(e),
+        Err(e) => panic!("{}", e),
     }
 }
 
diff --git a/common/deposit_contract/src/lib.rs b/common/deposit_contract/src/lib.rs
index e57f22dc0..92ccee3be 100644
--- a/common/deposit_contract/src/lib.rs
+++ b/common/deposit_contract/src/lib.rs
@@ -68,7 +68,7 @@ pub fn decode_eth1_tx_data(
             )
             .map_err(DecodeError::SszDecodeError)?
         };
-    };
+    }
 
     let root = decode_token!(Hash256, to_fixed_bytes);
 
diff --git a/common/lighthouse_version/src/lib.rs b/common/lighthouse_version/src/lib.rs
index 76f9cb411..233305d3c 100644
--- a/common/lighthouse_version/src/lib.rs
+++ b/common/lighthouse_version/src/lib.rs
@@ -38,6 +38,10 @@ mod test {
     fn version_formatting() {
         let re = Regex::new(r"^Lighthouse/v[0-9]+\.[0-9]+\.[0-9]+(-rc.[0-9])?-[[:xdigit:]]{7}\+?$")
             .unwrap();
-        assert!(re.is_match(VERSION), VERSION);
+        assert!(
+            re.is_match(VERSION),
+            "version doesn't match regex: {}",
+            VERSION
+        );
     }
 }
diff --git a/common/remote_signer_consumer/tests/post.rs b/common/remote_signer_consumer/tests/post.rs
index 7448ed130..68a45aac3 100644
--- a/common/remote_signer_consumer/tests/post.rs
+++ b/common/remote_signer_consumer/tests/post.rs
@@ -149,7 +149,7 @@ mod post {
             let r = run_testcase(u).unwrap_err();
 
             for msg in msgs.iter() {
-                assert!(r.contains(msg), format!("{:?} should contain {:?}", r, msg));
+                assert!(r.contains(msg), "{:?} should contain {:?}", r, msg);
             }
         };
 
diff --git a/common/validator_dir/src/validator_dir.rs b/common/validator_dir/src/validator_dir.rs
index 5706b6630..bfa3e2553 100644
--- a/common/validator_dir/src/validator_dir.rs
+++ b/common/validator_dir/src/validator_dir.rs
@@ -89,7 +89,7 @@ impl ValidatorDir {
     }
 
     /// Returns the `dir` provided to `Self::open`.
-    pub fn dir(&self) -> &PathBuf {
+    pub fn dir(&self) -> &Path {
         &self.dir
     }
 
@@ -204,7 +204,7 @@ impl ValidatorDir {
 
 /// Attempts to load and decrypt a Keypair given path to the keystore.
 pub fn unlock_keypair<P: AsRef<Path>>(
-    keystore_path: &PathBuf,
+    keystore_path: &Path,
     password_dir: P,
 ) -> Result<Keypair, Error> {
     let keystore = Keystore::from_json_reader(
@@ -229,8 +229,8 @@ pub fn unlock_keypair<P: AsRef<Path>>(
 
 /// Attempts to load and decrypt a Keypair given path to the keystore and the password file.
 pub fn unlock_keypair_from_password_path(
-    keystore_path: &PathBuf,
-    password_path: &PathBuf,
+    keystore_path: &Path,
+    password_path: &Path,
 ) -> Result<Keypair, Error> {
     let keystore = Keystore::from_json_reader(
         &mut OpenOptions::new()
@@ -242,7 +242,7 @@ pub fn unlock_keypair_from_password_path(
     .map_err(Error::UnableToReadKeystore)?;
 
     let password: PlainText = read(password_path)
-        .map_err(|_| Error::UnableToReadPassword(password_path.clone()))?
+        .map_err(|_| Error::UnableToReadPassword(password_path.into()))?
         .into();
     keystore
         .decrypt_keypair(password.as_bytes())
diff --git a/common/validator_dir/tests/tests.rs b/common/validator_dir/tests/tests.rs
index 3a54c22f5..a782d81bb 100644
--- a/common/validator_dir/tests/tests.rs
+++ b/common/validator_dir/tests/tests.rs
@@ -182,7 +182,7 @@ fn concurrency() {
     let harness = Harness::new();
 
     let val_dir = harness.create_and_test(&BuildConfig::default());
-    let path = val_dir.dir().clone();
+    let path = val_dir.dir().to_owned();
 
     // Should not re-open whilst opened after build.
     ValidatorDir::open(&path).unwrap_err();
diff --git a/consensus/serde_utils/src/hex.rs b/consensus/serde_utils/src/hex.rs
index 7ffa347e5..647b0ecfb 100644
--- a/consensus/serde_utils/src/hex.rs
+++ b/consensus/serde_utils/src/hex.rs
@@ -55,8 +55,8 @@ impl<'de> Visitor<'de> for HexVisitor {
     where
         E: de::Error,
     {
-        Ok(hex::decode(value.trim_start_matches("0x"))
-            .map_err(|e| de::Error::custom(format!("invalid hex ({:?})", e)))?)
+        hex::decode(value.trim_start_matches("0x"))
+            .map_err(|e| de::Error::custom(format!("invalid hex ({:?})", e)))
     }
 }
 
diff --git a/consensus/ssz/src/decode/impls.rs b/consensus/ssz/src/decode/impls.rs
index 29c8c1550..f074cd341 100644
--- a/consensus/ssz/src/decode/impls.rs
+++ b/consensus/ssz/src/decode/impls.rs
@@ -353,7 +353,7 @@ macro_rules! impl_decodable_for_u8_array {
                     Err(DecodeError::InvalidByteLength { len, expected })
                 } else {
                     let mut array: [u8; $len] = [0; $len];
-                    array.copy_from_slice(&bytes[..]);
+                    array.copy_from_slice(bytes);
 
                     Ok(array)
                 }
diff --git a/consensus/ssz_types/src/fixed_vector.rs b/consensus/ssz_types/src/fixed_vector.rs
index 9ae0d06ba..0d7664c1d 100644
--- a/consensus/ssz_types/src/fixed_vector.rs
+++ b/consensus/ssz_types/src/fixed_vector.rs
@@ -108,9 +108,9 @@ impl<T: Default, N: Unsigned> From<Vec<T>> for FixedVector<T, N> {
     }
 }
 
-impl<T, N: Unsigned> Into<Vec<T>> for FixedVector<T, N> {
-    fn into(self) -> Vec<T> {
-        self.vec
+impl<T, N: Unsigned> From<FixedVector<T, N>> for Vec<T> {
+    fn from(vector: FixedVector<T, N>) -> Vec<T> {
+        vector.vec
     }
 }
 
diff --git a/consensus/ssz_types/src/variable_list.rs b/consensus/ssz_types/src/variable_list.rs
index 4cbef6743..6c58ac690 100644
--- a/consensus/ssz_types/src/variable_list.rs
+++ b/consensus/ssz_types/src/variable_list.rs
@@ -120,9 +120,9 @@ impl<T, N: Unsigned> From<Vec<T>> for VariableList<T, N> {
     }
 }
 
-impl<T, N: Unsigned> Into<Vec<T>> for VariableList<T, N> {
-    fn into(self) -> Vec<T> {
-        self.vec
+impl<T, N: Unsigned> From<VariableList<T, N>> for Vec<T> {
+    fn from(list: VariableList<T, N>) -> Vec<T> {
+        list.vec
     }
 }
 
diff --git a/consensus/types/src/chain_spec.rs b/consensus/types/src/chain_spec.rs
index 1778d50fb..b6cb5142f 100644
--- a/consensus/types/src/chain_spec.rs
+++ b/consensus/types/src/chain_spec.rs
@@ -1,6 +1,7 @@
 use crate::*;
 use int_to_bytes::int_to_bytes4;
 use serde_derive::{Deserialize, Serialize};
+use std::collections::HashMap;
 use std::fs::File;
 use std::path::Path;
 use tree_hash::TreeHash;
@@ -449,10 +450,8 @@ mod tests {
 }
 
 /// YAML config file as defined by the spec.
-///
-/// Spec v0.12.3
 #[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
-#[serde(rename_all = "UPPERCASE", deny_unknown_fields)]
+#[serde(rename_all = "UPPERCASE")]
 pub struct YamlConfig {
     pub config_name: String,
     // ChainSpec
@@ -576,6 +575,10 @@ pub struct YamlConfig {
     #[serde(with = "serde_utils::quoted_u64")]
     deposit_network_id: u64,
     deposit_contract_address: Address,
+
+    // Extra fields (could be from a future hard-fork that we don't yet know).
+    #[serde(flatten)]
+    pub extra_fields: HashMap<String, String>,
 }
 
 impl Default for YamlConfig {
@@ -671,6 +674,8 @@ impl YamlConfig {
             deposit_chain_id: spec.deposit_chain_id,
             deposit_network_id: spec.deposit_network_id,
             deposit_contract_address: spec.deposit_contract_address,
+
+            extra_fields: HashMap::new(),
         }
     }
 
@@ -849,6 +854,31 @@ mod yaml_tests {
         assert_eq!(from, yamlconfig);
     }
 
+    #[test]
+    fn extra_fields_round_trip() {
+        let tmp_file = NamedTempFile::new().expect("failed to create temp file");
+        let writer = OpenOptions::new()
+            .read(false)
+            .write(true)
+            .open(tmp_file.as_ref())
+            .expect("error opening file");
+        let mainnet_spec = ChainSpec::mainnet();
+        let mut yamlconfig = YamlConfig::from_spec::<MainnetEthSpec>(&mainnet_spec);
+        let (k1, v1) = ("SAMPLE_HARDFORK_KEY1", "123456789");
+        let (k2, v2) = ("SAMPLE_HARDFORK_KEY2", "987654321");
+        yamlconfig.extra_fields.insert(k1.into(), v1.into());
+        yamlconfig.extra_fields.insert(k2.into(), v2.into());
+        serde_yaml::to_writer(writer, &yamlconfig).expect("failed to write or serialize");
+
+        let reader = OpenOptions::new()
+            .read(true)
+            .write(false)
+            .open(tmp_file.as_ref())
+            .expect("error while opening the file");
+        let from: YamlConfig = serde_yaml::from_reader(reader).expect("error while deserializing");
+        assert_eq!(from, yamlconfig);
+    }
+
     #[test]
     fn apply_to_spec() {
         let mut spec = ChainSpec::minimal();
diff --git a/crypto/bls/src/generic_signature_set.rs b/crypto/bls/src/generic_signature_set.rs
index 285667898..16f845fc4 100644
--- a/crypto/bls/src/generic_signature_set.rs
+++ b/crypto/bls/src/generic_signature_set.rs
@@ -19,35 +19,35 @@ where
     aggregate: Cow<'a, GenericAggregateSignature<Pub, AggPub, Sig, AggSig>>,
 }
 
-impl<'a, Pub, AggPub, Sig, AggSig> Into<WrappedSignature<'a, Pub, AggPub, Sig, AggSig>>
-    for &'a GenericSignature<Pub, Sig>
+impl<'a, Pub, AggPub, Sig, AggSig> From<&'a GenericSignature<Pub, Sig>>
+    for WrappedSignature<'a, Pub, AggPub, Sig, AggSig>
 where
     Pub: TPublicKey + Clone,
     AggPub: Clone,
     Sig: TSignature<Pub> + Clone,
     AggSig: TAggregateSignature<Pub, AggPub, Sig> + Clone,
 {
-    fn into(self) -> WrappedSignature<'a, Pub, AggPub, Sig, AggSig> {
+    fn from(sig: &'a GenericSignature<Pub, Sig>) -> Self {
         let mut aggregate: GenericAggregateSignature<Pub, AggPub, Sig, AggSig> =
             GenericAggregateSignature::infinity();
-        aggregate.add_assign(self);
+        aggregate.add_assign(sig);
         WrappedSignature {
             aggregate: Cow::Owned(aggregate),
         }
     }
 }
 
-impl<'a, Pub, AggPub, Sig, AggSig> Into<WrappedSignature<'a, Pub, AggPub, Sig, AggSig>>
-    for &'a GenericAggregateSignature<Pub, AggPub, Sig, AggSig>
+impl<'a, Pub, AggPub, Sig, AggSig> From<&'a GenericAggregateSignature<Pub, AggPub, Sig, AggSig>>
+    for WrappedSignature<'a, Pub, AggPub, Sig, AggSig>
 where
     Pub: TPublicKey + Clone,
     AggPub: Clone,
     Sig: Clone,
     AggSig: Clone,
 {
-    fn into(self) -> WrappedSignature<'a, Pub, AggPub, Sig, AggSig> {
+    fn from(aggregate: &'a GenericAggregateSignature<Pub, AggPub, Sig, AggSig>) -> Self {
         WrappedSignature {
-            aggregate: Cow::Borrowed(self),
+            aggregate: Cow::Borrowed(aggregate),
         }
     }
 }
diff --git a/testing/ef_tests/tests/tests.rs b/testing/ef_tests/tests/tests.rs
index 72bede138..c1a50ffc4 100644
--- a/testing/ef_tests/tests/tests.rs
+++ b/testing/ef_tests/tests/tests.rs
@@ -1,6 +1,7 @@
 #![cfg(feature = "ef_tests")]
 
 use ef_tests::*;
+use std::collections::HashMap;
 use std::path::PathBuf;
 use types::*;
 
@@ -17,6 +18,11 @@ fn config_test<E: EthSpec + TypeName>() {
     let yaml_from_spec = YamlConfig::from_spec::<E>(&spec);
     assert_eq!(yaml_config.apply_to_chain_spec::<E>(&spec), Some(spec));
     assert_eq!(yaml_from_spec, yaml_config);
+    assert_eq!(
+        yaml_config.extra_fields,
+        HashMap::new(),
+        "not all config fields read"
+    );
 }
 
 #[test]
diff --git a/testing/state_transition_vectors/src/main.rs b/testing/state_transition_vectors/src/main.rs
index e259399a7..4f8426bae 100644
--- a/testing/state_transition_vectors/src/main.rs
+++ b/testing/state_transition_vectors/src/main.rs
@@ -7,7 +7,7 @@ use state_processing::test_utils::BlockProcessingBuilder;
 use std::env;
 use std::fs::{self, File};
 use std::io::Write;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::process::exit;
 use types::MainnetEthSpec;
 use types::{BeaconState, ChainSpec, EthSpec, SignedBeaconBlock};
@@ -91,12 +91,12 @@ fn write_vectors_to_file(title: &str, vectors: &[TestVector]) -> Result<(), Stri
 }
 
 /// Write some SSZ object to file.
-fn write_to_ssz_file<T: Encode>(path: &PathBuf, item: &T) -> Result<(), String> {
+fn write_to_ssz_file<T: Encode>(path: &Path, item: &T) -> Result<(), String> {
     write_to_file(path, &item.as_ssz_bytes())
 }
 
 /// Write some bytes to file.
-fn write_to_file(path: &PathBuf, item: &[u8]) -> Result<(), String> {
+fn write_to_file(path: &Path, item: &[u8]) -> Result<(), String> {
     File::create(path)
         .map_err(|e| format!("Unable to create {:?}: {:?}", path, e))
         .and_then(|mut file| {
diff --git a/validator_client/src/beacon_node_fallback.rs b/validator_client/src/beacon_node_fallback.rs
index 65d8ae6d6..78def569e 100644
--- a/validator_client/src/beacon_node_fallback.rs
+++ b/validator_client/src/beacon_node_fallback.rs
@@ -7,7 +7,7 @@ use crate::http_metrics::metrics::{inc_counter_vec, ENDPOINT_ERRORS, ENDPOINT_RE
 use environment::RuntimeContext;
 use eth2::BeaconNodeHttpClient;
 use futures::future;
-use slog::{error, info, warn, Logger};
+use slog::{debug, error, info, warn, Logger};
 use slot_clock::SlotClock;
 use std::fmt;
 use std::fmt::Debug;
@@ -236,6 +236,14 @@ impl<E: EthSpec> CandidateBeaconNode<E> {
                 CandidateError::Incompatible
             })?;
 
+        if !yaml_config.extra_fields.is_empty() {
+            debug!(
+                log,
+                "Beacon spec includes unknown fields";
+                "fields" => ?yaml_config.extra_fields
+            );
+        }
+
         if *spec == beacon_node_spec {
             Ok(())
         } else {
diff --git a/validator_client/src/initialized_validators.rs b/validator_client/src/initialized_validators.rs
index 1475cd995..f89a1096e 100644
--- a/validator_client/src/initialized_validators.rs
+++ b/validator_client/src/initialized_validators.rs
@@ -19,7 +19,7 @@ use slog::{debug, error, info, warn, Logger};
 use std::collections::{HashMap, HashSet};
 use std::fs::File;
 use std::io;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use types::{Graffiti, Keypair, PublicKey, PublicKeyBytes};
 
 use crate::key_cache;
@@ -101,20 +101,16 @@ impl InitializedValidator {
     }
 }
 
-fn open_keystore(path: &PathBuf) -> Result<Keystore, Error> {
+fn open_keystore(path: &Path) -> Result<Keystore, Error> {
     let keystore_file = File::open(path).map_err(Error::UnableToOpenVotingKeystore)?;
     Keystore::from_json_reader(keystore_file).map_err(Error::UnableToParseVotingKeystore)
 }
 
-fn get_lockfile_path(file_path: &PathBuf) -> Option<PathBuf> {
+fn get_lockfile_path(file_path: &Path) -> Option<PathBuf> {
     file_path
         .file_name()
         .and_then(|os_str| os_str.to_str())
-        .map(|filename| {
-            file_path
-                .clone()
-                .with_file_name(format!("{}.lock", filename))
-        })
+        .map(|filename| file_path.with_file_name(format!("{}.lock", filename)))
 }
 
 impl InitializedValidator {
@@ -238,7 +234,7 @@ impl InitializedValidator {
 /// Try to unlock `keystore` at `keystore_path` by prompting the user via `stdin`.
 fn unlock_keystore_via_stdin_password(
     keystore: &Keystore,
-    keystore_path: &PathBuf,
+    keystore_path: &Path,
 ) -> Result<(ZeroizeString, Keypair), Error> {
     eprintln!();
     eprintln!(