diff --git a/Cargo.lock b/Cargo.lock
index 438a0d67bcc..bb89be0b691 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -768,10 +768,11 @@ dependencies = [
 [[package]]
 name = "crossbeam-epoch"
 version = "0.9.3"
-source = "git+https://github.com/tikv/crossbeam.git?branch=tikv-5.0#e0e083d062649484188b7337fe388fd12f2c8d94"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2584f639eb95fea8c798496315b297cf81b9b58b6d30ab066a75455333cf4b12"
 dependencies = [
  "cfg-if 1.0.0",
- "crossbeam-utils 0.8.3 (git+https://github.com/tikv/crossbeam.git?branch=tikv-5.0)",
+ "crossbeam-utils 0.8.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static",
  "memoffset",
  "scopeguard",
@@ -780,11 +781,10 @@ dependencies = [
 [[package]]
 name = "crossbeam-epoch"
 version = "0.9.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2584f639eb95fea8c798496315b297cf81b9b58b6d30ab066a75455333cf4b12"
+source = "git+https://github.com/tikv/crossbeam.git?branch=tikv-5.0#e0e083d062649484188b7337fe388fd12f2c8d94"
 dependencies = [
  "cfg-if 1.0.0",
- "crossbeam-utils 0.8.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.8.3 (git+https://github.com/tikv/crossbeam.git?branch=tikv-5.0)",
  "lazy_static",
  "memoffset",
  "scopeguard",
@@ -825,7 +825,8 @@ dependencies = [
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.3"
-source = "git+https://github.com/tikv/crossbeam.git?branch=tikv-5.0#e0e083d062649484188b7337fe388fd12f2c8d94"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7e9d99fa91428effe99c5c6d4634cdeba32b8cf784fc428a2a687f61a952c49"
 dependencies = [
  "autocfg",
  "cfg-if 1.0.0",
@@ -835,8 +836,7 @@ dependencies = [
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e7e9d99fa91428effe99c5c6d4634cdeba32b8cf784fc428a2a687f61a952c49"
+source = "git+https://github.com/tikv/crossbeam.git?branch=tikv-5.0#e0e083d062649484188b7337fe388fd12f2c8d94"
 dependencies = [
  "autocfg",
  "cfg-if 1.0.0",
diff --git a/cmd/tikv-ctl/src/main.rs b/cmd/tikv-ctl/src/main.rs
index 15ae3a45a51..0a840ae81d5 100644
--- a/cmd/tikv-ctl/src/main.rs
+++ b/cmd/tikv-ctl/src/main.rs
@@ -1891,7 +1891,7 @@ fn main() {
 
     // Bypass the ldb command to RocksDB.
     if let Some(cmd) = matches.subcommand_matches("ldb") {
-        run_ldb_command(&cmd, &cfg);
+        run_ldb_command(cmd, &cfg);
         return;
     }
 
diff --git a/components/backup/src/endpoint.rs b/components/backup/src/endpoint.rs
index 4d1f0488818..804975a4139 100644
--- a/components/backup/src/endpoint.rs
+++ b/components/backup/src/endpoint.rs
@@ -169,7 +169,7 @@ impl BackupRange {
                 |key, lock| {
                     Lock::check_ts_conflict(
                         Cow::Borrowed(lock),
-                        &key,
+                        key,
                         backup_ts,
                         &Default::default(),
                     )
@@ -507,8 +507,8 @@ impl<R: RegionInfoProvider> Progress<R> {
                         }
                     }
                     if info.role == StateRole::Leader {
-                        let ekey = get_min_end_key(end_key.as_ref(), &region);
-                        let skey = get_max_start_key(start_key.as_ref(), &region);
+                        let ekey = get_min_end_key(end_key.as_ref(), region);
+                        let skey = get_max_start_key(start_key.as_ref(), region);
                         assert!(!(skey == ekey && ekey.is_some()), "{:?} {:?}", skey, ekey);
                         let leader = find_peer(region, store_id).unwrap().to_owned();
                         let backup_range = BackupRange {
diff --git a/components/cdc/src/channel.rs b/components/cdc/src/channel.rs
index 3c0dde368d6..47810fdbb8e 100644
--- a/components/cdc/src/channel.rs
+++ b/components/cdc/src/channel.rs
@@ -281,6 +281,7 @@ where
 mod tests {
     use super::*;
 
+    use std::assert_matches::assert_matches;
     use std::sync::mpsc;
     use std::time::Duration;
 
diff --git a/components/cdc/src/endpoint.rs b/components/cdc/src/endpoint.rs
index 517db7ffb72..759eb8cd024 100644
--- a/components/cdc/src/endpoint.rs
+++ b/components/cdc/src/endpoint.rs
@@ -904,7 +904,7 @@ impl<T: 'static + RaftStoreRouter<E>, E: KvEngine> Endpoint<T, E> {
             for (region_id, _) in regions {
                 if let Some(region) = meta.regions.get(&region_id) {
                     if let Some((term, leader_id)) = meta.leaders.get(&region_id) {
-                        let leader_store_id = find_store_id(&region, *leader_id);
+                        let leader_store_id = find_store_id(region, *leader_id);
                         if leader_store_id.is_none() {
                             continue;
                         }
diff --git a/components/cdc/src/old_value.rs b/components/cdc/src/old_value.rs
index b0bec738636..75c0bb0c349 100644
--- a/components/cdc/src/old_value.rs
+++ b/components/cdc/src/old_value.rs
@@ -90,7 +90,7 @@ impl<S: EngineSnapshot> OldValueReader<S> {
         let mut opts = ReadOptions::new();
         opts.set_fill_cache(false);
         self.snapshot
-            .get_cf_opt(opts, CF_DEFAULT, &key)
+            .get_cf_opt(opts, CF_DEFAULT, key)
             .unwrap()
             .map(|v| v.deref().to_vec())
     }
diff --git a/components/cdc/tests/mod.rs b/components/cdc/tests/mod.rs
index aa260d41ec8..0a9d2c368b4 100644
--- a/components/cdc/tests/mod.rs
+++ b/components/cdc/tests/mod.rs
@@ -155,7 +155,7 @@ impl TestSuiteBuilder {
         for (id, worker) in &mut endpoints {
             let sim = cluster.sim.wl();
             let raft_router = sim.get_server_router(*id);
-            let cdc_ob = obs.get(&id).unwrap().clone();
+            let cdc_ob = obs.get(id).unwrap().clone();
             let cm = sim.get_concurrency_manager(*id);
             let env = Arc::new(Environment::new(1));
             let mut cdc_endpoint = cdc::Endpoint::new(
diff --git a/components/cloud/aws/src/s3.rs b/components/cloud/aws/src/s3.rs
index d040dfb0836..6c8440d1cee 100644
--- a/components/cloud/aws/src/s3.rs
+++ b/components/cloud/aws/src/s3.rs
@@ -131,7 +131,7 @@ impl Config {
 
 impl BlobConfig for Config {
     fn name(&self) -> &'static str {
-        &STORAGE_NAME
+        STORAGE_NAME
     }
 
     fn url(&self) -> io::Result<url::Url> {
diff --git a/components/cloud/gcp/src/gcs.rs b/components/cloud/gcp/src/gcs.rs
index 135af1f875d..37d52eaf234 100644
--- a/components/cloud/gcp/src/gcs.rs
+++ b/components/cloud/gcp/src/gcs.rs
@@ -111,7 +111,7 @@ fn deserialize_service_account_info(
 
 impl BlobConfig for Config {
     fn name(&self) -> &'static str {
-        &STORAGE_NAME
+        STORAGE_NAME
     }
 
     fn url(&self) -> io::Result<url::Url> {
diff --git a/components/cloud/src/blob.rs b/components/cloud/src/blob.rs
index ec9beef057c..809ad5f67f7 100644
--- a/components/cloud/src/blob.rs
+++ b/components/cloud/src/blob.rs
@@ -136,7 +136,7 @@ impl BucketConf {
         let path = none_to_empty(self.prefix.clone());
         if let Some(ep) = &self.endpoint {
             let mut u =
-                url::Url::parse(&ep).map_err(|e| format!("invalid endpoint {}: {}", &ep, e))?;
+                url::Url::parse(ep).map_err(|e| format!("invalid endpoint {}: {}", &ep, e))?;
             u.set_path(&format!(
                 "{}/{}",
                 &self.bucket.trim_end_matches('/'),
diff --git a/components/concurrency_manager/benches/lock_table.rs b/components/concurrency_manager/benches/lock_table.rs
index e6561bf5ce0..9360b49346a 100644
--- a/components/concurrency_manager/benches/lock_table.rs
+++ b/components/concurrency_manager/benches/lock_table.rs
@@ -1,6 +1,7 @@
 // Copyright 2021 TiKV Project Authors. Licensed under Apache-2.0.
 
 #![feature(test)]
+#![feature(bench_black_box)]
 
 use concurrency_manager::ConcurrencyManager;
 use criterion::*;
@@ -58,7 +59,7 @@ fn bench_point_check(c: &mut Criterion) {
             thread_rng().fill_bytes(&mut buf[..]);
             let key = Key::from_raw(&buf);
             let _ = cm.read_key_check(&key, |l| {
-                Lock::check_ts_conflict(Cow::Borrowed(&l), &key, 1.into(), &ts_set)
+                Lock::check_ts_conflict(Cow::Borrowed(l), &key, 1.into(), &ts_set)
             });
         })
     });
@@ -84,7 +85,7 @@ fn bench_range_check(c: &mut Criterion) {
             let end_key = Key::from_raw(&[start + 25]);
             // The key range is roughly 1/10 the key space.
             let _ = cm.read_range_check(Some(&start_key), Some(&end_key), |key, l| {
-                Lock::check_ts_conflict(Cow::Borrowed(&l), &key, 1.into(), &ts_set)
+                Lock::check_ts_conflict(Cow::Borrowed(l), key, 1.into(), &ts_set)
             });
         })
     });
diff --git a/components/encryption/src/crypter.rs b/components/encryption/src/crypter.rs
index f07d80c3863..07f60691269 100644
--- a/components/encryption/src/crypter.rs
+++ b/components/encryption/src/crypter.rs
@@ -162,7 +162,7 @@ impl<'k> AesGcmCrypter<'k> {
             &self.key.0,
             Some(self.iv.as_slice()),
             &[], /* AAD */
-            &pt,
+            pt,
             &mut tag.0,
         )?;
         Ok((ciphertext, tag))
@@ -175,7 +175,7 @@ impl<'k> AesGcmCrypter<'k> {
             &self.key.0,
             Some(self.iv.as_slice()),
             &[], /* AAD */
-            &ct,
+            ct,
             &tag.0,
         )?;
         Ok(plaintext)
diff --git a/components/encryption/src/encrypted_file/mod.rs b/components/encryption/src/encrypted_file/mod.rs
index ccd078d97cb..ec3c6f04217 100644
--- a/components/encryption/src/encrypted_file/mod.rs
+++ b/components/encryption/src/encrypted_file/mod.rs
@@ -74,7 +74,7 @@ impl<'a> EncryptedFile<'a> {
 
         // Encrypt the content.
         let encrypted_content = master_key
-            .encrypt(&plaintext_content)?
+            .encrypt(plaintext_content)?
             .write_to_bytes()
             .unwrap();
         let header = Header::new(&encrypted_content, Version::V1);
diff --git a/components/encryption/src/io.rs b/components/encryption/src/io.rs
index 6fe2359987b..e67def753dc 100644
--- a/components/encryption/src/io.rs
+++ b/components/encryption/src/io.rs
@@ -106,7 +106,7 @@ impl<R> CrypterReader<R> {
         mode: Mode,
         iv: Option<Iv>,
     ) -> Result<(CrypterReader<R>, Iv)> {
-        crate::verify_encryption_config(method, &key)?;
+        crate::verify_encryption_config(method, key)?;
         let iv = iv.unwrap_or_else(Iv::new_ctr);
         let (cipher, crypter) = create_aes_ctr_crypter(method, key, mode, iv)?;
         let block_size = cipher.block_size();
@@ -178,7 +178,7 @@ impl<W: Write> EncrypterWriter<W> {
         key: &[u8],
         iv: Iv,
     ) -> Result<EncrypterWriter<W>> {
-        crate::verify_encryption_config(method, &key)?;
+        crate::verify_encryption_config(method, key)?;
         let (cipher, crypter) = create_aes_ctr_crypter(method, key, Mode::Encrypt, iv)?;
         let block_size = cipher.block_size();
         Ok(EncrypterWriter {
diff --git a/components/engine_rocks/src/import.rs b/components/engine_rocks/src/import.rs
index aa50694884d..ef7d816197b 100644
--- a/components/engine_rocks/src/import.rs
+++ b/components/engine_rocks/src/import.rs
@@ -22,7 +22,7 @@ impl ImportExt for RocksEngine {
             // Prior to v5.2.0, TiKV use `write_global_seqno=true` for ingestion. For backward
             // compatibility, in case TiKV is retrying an ingestion job generated by older
             // version, it needs to reset the global seqno to 0.
-            set_external_sst_file_global_seq_no(&self.as_inner(), cf, file, 0)?;
+            set_external_sst_file_global_seq_no(self.as_inner(), cf, file, 0)?;
             f.sync_all()
                 .map_err(|e| format!("sync {}: {:?}", file, e))?;
             Ok(())
@@ -34,7 +34,7 @@ impl ImportExt for RocksEngine {
         // the manual memtable flush was taken.
         let _did_nonblocking_memtable_flush = self
             .as_inner()
-            .ingest_external_file_optimized(&cf, &opts.0, files)?;
+            .ingest_external_file_optimized(cf, &opts.0, files)?;
         Ok(())
     }
 }
diff --git a/components/engine_rocks/src/misc.rs b/components/engine_rocks/src/misc.rs
index cde1ad59f4e..1528601afe6 100644
--- a/components/engine_rocks/src/misc.rs
+++ b/components/engine_rocks/src/misc.rs
@@ -179,7 +179,7 @@ impl MiscExt for RocksEngine {
             }
             DeleteStrategy::DeleteByKey => {
                 for r in ranges {
-                    self.delete_all_in_range_cf_by_key(cf, &r)?;
+                    self.delete_all_in_range_cf_by_key(cf, r)?;
                 }
             }
             DeleteStrategy::DeleteByWriter { sst_path } => {
@@ -320,7 +320,7 @@ impl MiscExt for RocksEngine {
         let handle = util::get_cf_handle(self.as_inner(), cf)?;
         Ok(crate::util::get_cf_num_files_at_level(
             self.as_inner(),
-            &handle,
+            handle,
             level,
         ))
     }
@@ -329,7 +329,7 @@ impl MiscExt for RocksEngine {
         let handle = util::get_cf_handle(self.as_inner(), cf)?;
         Ok(crate::util::get_cf_num_immutable_mem_table(
             self.as_inner(),
-            &handle,
+            handle,
         ))
     }
 
@@ -337,7 +337,7 @@ impl MiscExt for RocksEngine {
         let handle = util::get_cf_handle(self.as_inner(), cf)?;
         Ok(crate::util::get_cf_compaction_pending_bytes(
             self.as_inner(),
-            &handle,
+            handle,
         ))
     }
 
diff --git a/components/engine_rocks/src/mvcc_properties.rs b/components/engine_rocks/src/mvcc_properties.rs
index e50b7ef99b4..91846e22235 100644
--- a/components/engine_rocks/src/mvcc_properties.rs
+++ b/components/engine_rocks/src/mvcc_properties.rs
@@ -55,7 +55,7 @@ impl MvccPropertiesExt for RocksEngine {
         start_key: &[u8],
         end_key: &[u8],
     ) -> Option<MvccProperties> {
-        let collection = match self.get_range_properties_cf(cf, &start_key, &end_key) {
+        let collection = match self.get_range_properties_cf(cf, start_key, end_key) {
             Ok(c) if !c.is_empty() => c,
             _ => return None,
         };
diff --git a/components/engine_rocks/src/range_properties.rs b/components/engine_rocks/src/range_properties.rs
index 18d4c452a34..53d2faeabc4 100644
--- a/components/engine_rocks/src/range_properties.rs
+++ b/components/engine_rocks/src/range_properties.rs
@@ -24,7 +24,7 @@ impl RangePropertiesExt for RocksEngine {
         let start = &range.start_key;
         let end = &range.end_key;
         let (_, keys) =
-            get_range_entries_and_versions(self, CF_WRITE, &start, &end).unwrap_or_default();
+            get_range_entries_and_versions(self, CF_WRITE, start, end).unwrap_or_default();
         Ok(keys)
     }
 
@@ -65,8 +65,8 @@ impl RangePropertiesExt for RocksEngine {
                 .join(", ");
             info!(
                 "range contains too many keys";
-                "start" => log_wrappers::Value::key(&range.start_key),
-                "end" => log_wrappers::Value::key(&range.end_key),
+                "start" => log_wrappers::Value::key(range.start_key),
+                "end" => log_wrappers::Value::key(range.end_key),
                 "total_keys" => total_keys,
                 "memtable" => mem_keys,
                 "ssts_keys" => ssts,
@@ -100,10 +100,10 @@ impl RangePropertiesExt for RocksEngine {
         let (_, mem_size) = box_try!(self.get_approximate_memtable_stats_cf(cfname, &range));
         total_size += mem_size;
 
-        let collection = box_try!(self.get_range_properties_cf(cfname, &start_key, &end_key));
+        let collection = box_try!(self.get_range_properties_cf(cfname, start_key, end_key));
         for (_, v) in collection.iter() {
             let props = box_try!(RangeProperties::decode(v.user_collected_properties()));
-            total_size += props.get_approximate_size_in_range(&start_key, &end_key);
+            total_size += props.get_approximate_size_in_range(start_key, end_key);
         }
 
         if large_threshold != 0 && total_size > large_threshold {
@@ -111,7 +111,7 @@ impl RangePropertiesExt for RocksEngine {
                 .iter()
                 .map(|(k, v)| {
                     let props = RangeProperties::decode(v.user_collected_properties()).unwrap();
-                    let size = props.get_approximate_size_in_range(&start_key, &end_key);
+                    let size = props.get_approximate_size_in_range(start_key, end_key);
                     format!(
                         "{}:{}",
                         Path::new(&*k)
@@ -125,8 +125,8 @@ impl RangePropertiesExt for RocksEngine {
                 .join(", ");
             info!(
                 "range size is too large";
-                "start" => log_wrappers::Value::key(&range.start_key),
-                "end" => log_wrappers::Value::key(&range.end_key),
+                "start" => log_wrappers::Value::key(range.start_key),
+                "end" => log_wrappers::Value::key(range.end_key),
                 "total_size" => total_size,
                 "memtable" => mem_size,
                 "ssts_size" => ssts,
@@ -168,7 +168,7 @@ impl RangePropertiesExt for RocksEngine {
     ) -> Result<Vec<Vec<u8>>> {
         let start_key = &range.start_key;
         let end_key = &range.end_key;
-        let collection = box_try!(self.get_range_properties_cf(cfname, &start_key, &end_key));
+        let collection = box_try!(self.get_range_properties_cf(cfname, start_key, end_key));
 
         let mut keys = vec![];
         for (_, v) in collection.iter() {
diff --git a/components/engine_rocks/src/raw_util.rs b/components/engine_rocks/src/raw_util.rs
index 790a91f702a..db0b1ef39a2 100644
--- a/components/engine_rocks/src/raw_util.rs
+++ b/components/engine_rocks/src/raw_util.rs
@@ -56,7 +56,7 @@ fn adjust_dynamic_level_bytes(
     cf_descs: &[CColumnFamilyDescriptor],
     cf_options: &mut CFOptions<'_>,
 ) {
-    if let Some(ref cf_desc) = cf_descs
+    if let Some(cf_desc) = cf_descs
         .iter()
         .find(|cf_desc| cf_desc.name() == cf_options.cf)
     {
diff --git a/components/engine_rocks/src/rocks_metrics.rs b/components/engine_rocks/src/rocks_metrics.rs
index 0014d09c40d..34e80243a43 100644
--- a/components/engine_rocks/src/rocks_metrics.rs
+++ b/components/engine_rocks/src/rocks_metrics.rs
@@ -1624,7 +1624,7 @@ mod tests {
         }
 
         let shared_block_cache = false;
-        flush_engine_properties(&engine.as_inner(), "kv", shared_block_cache);
+        flush_engine_properties(engine.as_inner(), "kv", shared_block_cache);
         let handle = engine.as_inner().cf_handle("default").unwrap();
         let info = engine
             .as_inner()
diff --git a/components/engine_rocks/src/ttl_properties.rs b/components/engine_rocks/src/ttl_properties.rs
index cc9b8138a67..7c93e815248 100644
--- a/components/engine_rocks/src/ttl_properties.rs
+++ b/components/engine_rocks/src/ttl_properties.rs
@@ -72,7 +72,7 @@ impl TablePropertiesCollector for TtlPropertiesCollector {
             return;
         }
 
-        let expire_ts = match get_expire_ts(&value) {
+        let expire_ts = match get_expire_ts(value) {
             Ok(ts) => ts,
             Err(e) => {
                 error!("failed to get expire ts";
diff --git a/components/engine_rocks/src/write_batch.rs b/components/engine_rocks/src/write_batch.rs
index d04e03d42df..f649d77351b 100644
--- a/components/engine_rocks/src/write_batch.rs
+++ b/components/engine_rocks/src/write_batch.rs
@@ -23,11 +23,11 @@ impl WriteBatchExt for RocksEngine {
     }
 
     fn write_batch(&self) -> Self::WriteBatch {
-        Self::WriteBatch::new(Arc::clone(&self.as_inner()))
+        Self::WriteBatch::new(Arc::clone(self.as_inner()))
     }
 
     fn write_batch_with_cap(&self, cap: usize) -> Self::WriteBatch {
-        Self::WriteBatch::with_capacity(Arc::clone(&self.as_inner()), cap)
+        Self::WriteBatch::with_capacity(Arc::clone(self.as_inner()), cap)
     }
 }
 
diff --git a/components/engine_traits_tests/src/ctor.rs b/components/engine_traits_tests/src/ctor.rs
index c156c31c502..f835741896a 100644
--- a/components/engine_traits_tests/src/ctor.rs
+++ b/components/engine_traits_tests/src/ctor.rs
@@ -69,7 +69,7 @@ fn new_engine_readonly_dir() {
     fs::set_permissions(&path, perms).unwrap();
 
     let path = path.to_str().unwrap();
-    let err = KvTestEngine::new_engine(&path, None, ALL_CFS, None);
+    let err = KvTestEngine::new_engine(path, None, ALL_CFS, None);
 
     assert!(err.is_err());
 }
@@ -93,7 +93,7 @@ fn new_engine_opt_readonly_dir() {
         .iter()
         .map(|cf| CFOptions::new(cf, ColumnFamilyOptions::new()))
         .collect();
-    let err = KvTestEngine::new_engine_opt(&path, db_opts, cf_opts);
+    let err = KvTestEngine::new_engine_opt(path, db_opts, cf_opts);
 
     assert!(err.is_err());
 }
diff --git a/components/external_storage/export/src/export.rs b/components/external_storage/export/src/export.rs
index ade9fd123e5..496ce5c9c80 100644
--- a/components/external_storage/export/src/export.rs
+++ b/components/external_storage/export/src/export.rs
@@ -163,9 +163,9 @@ fn create_backend_inner(backend: &Backend) -> io::Result<Box<dyn ExternalStorage
         Backend::Gcs(config) => blob_store(GCSStorage::from_input(config.clone())?),
         Backend::CloudDynamic(dyn_backend) => match dyn_backend.provider_name.as_str() {
             #[cfg(feature = "cloud-aws")]
-            "aws" | "s3" => blob_store(S3Storage::from_cloud_dynamic(&dyn_backend)?),
+            "aws" | "s3" => blob_store(S3Storage::from_cloud_dynamic(dyn_backend)?),
             #[cfg(feature = "cloud-gcp")]
-            "gcp" | "gcs" => blob_store(GCSStorage::from_cloud_dynamic(&dyn_backend)?),
+            "gcp" | "gcs" => blob_store(GCSStorage::from_cloud_dynamic(dyn_backend)?),
             _ => {
                 return Err(bad_backend(Backend::CloudDynamic(dyn_backend.clone())));
             }
@@ -337,7 +337,7 @@ impl ExternalStorage for EncryptedExternalStorage {
         block_on_external_io(read_external_storage_into_file(
             &mut input,
             file_writer,
-            &speed_limiter,
+            speed_limiter,
             expected_length,
             min_read_speed,
         ))
diff --git a/components/external_storage/src/local.rs b/components/external_storage/src/local.rs
index 2780f5eabd7..c74054f3c99 100644
--- a/components/external_storage/src/local.rs
+++ b/components/external_storage/src/local.rs
@@ -55,11 +55,11 @@ const STORAGE_NAME: &str = "local";
 
 impl ExternalStorage for LocalStorage {
     fn name(&self) -> &'static str {
-        &STORAGE_NAME
+        STORAGE_NAME
     }
 
     fn url(&self) -> io::Result<url::Url> {
-        Ok(url_for(&self.base.as_path()))
+        Ok(url_for(self.base.as_path()))
     }
 
     fn write(
diff --git a/components/external_storage/src/noop.rs b/components/external_storage/src/noop.rs
index 101d97d6fd1..33bdf1b3c14 100644
--- a/components/external_storage/src/noop.rs
+++ b/components/external_storage/src/noop.rs
@@ -24,7 +24,7 @@ const STORAGE_NAME: &str = "noop";
 
 impl ExternalStorage for NoopStorage {
     fn name(&self) -> &'static str {
-        &STORAGE_NAME
+        STORAGE_NAME
     }
 
     fn url(&self) -> io::Result<url::Url> {
diff --git a/components/online_config/online_config_derive/src/lib.rs b/components/online_config/online_config_derive/src/lib.rs
index d5c1741bc5c..483d7682c21 100644
--- a/components/online_config/online_config_derive/src/lib.rs
+++ b/components/online_config/online_config_derive/src/lib.rs
@@ -44,7 +44,7 @@ fn generate_token(ast: DeriveInput) -> std::result::Result<TokenStream, Error> {
     let get_encoder_fn = get_encoder(&encoder_name, &encoder_lt);
     let typed_fn = typed(&fields, &creat_name)?;
     let encoder_struct = encoder(
-        &name,
+        name,
         &creat_name,
         &encoder_name,
         &encoder_lt,
@@ -272,7 +272,7 @@ fn typed(fields: &Punctuated<Field, Comma>, creat_name: &Ident) -> Result<TokenS
 fn get_config_attrs(attrs: &[Attribute]) -> Result<(bool, bool, bool)> {
     let (mut skip, mut hidden, mut submodule) = (false, false, false);
     for attr in attrs {
-        if !is_attr("online_config", &attr) {
+        if !is_attr("online_config", attr) {
             continue;
         }
         match attr.parse_args::<Ident>()? {
diff --git a/components/pd_client/src/client.rs b/components/pd_client/src/client.rs
index 91f3b0e22ca..f4edbfacca3 100644
--- a/components/pd_client/src/client.rs
+++ b/components/pd_client/src/client.rs
@@ -66,7 +66,7 @@ impl RpcClient {
         // -1 means the max.
         let retries = match cfg.retry_max_count {
             -1 => std::isize::MAX,
-            v => v.checked_add(1).unwrap_or(std::isize::MAX),
+            v => v.saturating_add(1),
         };
         let monitor = Arc::new(
             yatp::Builder::new(thd_name!("pdmonitor"))
diff --git a/components/raftstore/src/coprocessor/dispatcher.rs b/components/raftstore/src/coprocessor/dispatcher.rs
index 5b9f406a9c3..c2885f486ea 100644
--- a/components/raftstore/src/coprocessor/dispatcher.rs
+++ b/components/raftstore/src/coprocessor/dispatcher.rs
@@ -505,7 +505,7 @@ impl<E: KvEngine> CoprocessorHost<E> {
         }
         for batch in &cmd_batches {
             for cmd in &batch.cmds {
-                self.post_apply(&batch.region, &cmd);
+                self.post_apply(&batch.region, cmd);
             }
         }
         for observer in &self.registry.cmd_observers {
diff --git a/components/raftstore/src/coprocessor/region_info_accessor.rs b/components/raftstore/src/coprocessor/region_info_accessor.rs
index c7e3335d22e..11995b59543 100644
--- a/components/raftstore/src/coprocessor/region_info_accessor.rs
+++ b/components/raftstore/src/coprocessor/region_info_accessor.rs
@@ -98,7 +98,7 @@ impl Display for RegionInfoQuery {
         match self {
             RegionInfoQuery::RaftStoreEvent(e) => write!(f, "RaftStoreEvent({:?})", e),
             RegionInfoQuery::SeekRegion { from, .. } => {
-                write!(f, "SeekRegion(from: {})", log_wrappers::Value::key(&from))
+                write!(f, "SeekRegion(from: {})", log_wrappers::Value::key(from))
             }
             RegionInfoQuery::FindRegionById { region_id, .. } => {
                 write!(f, "FindRegionById(region_id: {})", region_id)
@@ -693,14 +693,14 @@ mod tests {
         assert!(c.region_ranges.is_empty());
 
         for region in regions {
-            must_create_region(c, &region, StateRole::Follower);
+            must_create_region(c, region, StateRole::Follower);
         }
 
         let expected_regions: Vec<_> = regions
             .iter()
             .map(|r| (r.clone(), StateRole::Follower))
             .collect();
-        check_collection(&c, &expected_regions);
+        check_collection(c, &expected_regions);
     }
 
     fn must_create_region(c: &mut RegionCollector, region: &Region, role: StateRole) {
diff --git a/components/raftstore/src/coprocessor/split_check/size.rs b/components/raftstore/src/coprocessor/split_check/size.rs
index f658687c06a..08b901c874c 100644
--- a/components/raftstore/src/coprocessor/split_check/size.rs
+++ b/components/raftstore/src/coprocessor/split_check/size.rs
@@ -130,7 +130,7 @@ where
         let region_id = region.get_id();
         let region_size = match get_region_approximate_size(
             engine,
-            &region,
+            region,
             host.cfg.region_max_size.0 * host.cfg.batch_split_limit,
         ) {
             Ok(size) => size,
@@ -606,17 +606,20 @@ pub mod tests {
             engine.flush_cf(data_cf, true).unwrap();
         }
         let region = make_region(1, vec![], vec![]);
-        let split_keys = get_approximate_split_keys(&engine, &region, 0)
-            .unwrap()
-            .into_iter()
-            .map(|k| {
-                Key::from_encoded_slice(keys::origin_key(&k))
-                    .into_raw()
-                    .unwrap()
-            })
-            .collect::<Vec<Vec<u8>>>();
 
-        assert_eq!(split_keys.is_empty(), true);
+        assert_eq!(
+            get_approximate_split_keys(&engine, &region, 0)
+                .unwrap()
+                .into_iter()
+                .map(|k| {
+                    Key::from_encoded_slice(keys::origin_key(&k))
+                        .into_raw()
+                        .unwrap()
+                })
+                .next()
+                .is_none(),
+            true
+        );
         for i in 4..5 {
             let k = format!("key_{:03}", i).into_bytes();
             let k = keys::data_key(Key::from_raw(&k).as_encoded());
diff --git a/components/raftstore/src/coprocessor/split_check/table.rs b/components/raftstore/src/coprocessor/split_check/table.rs
index 9da785b8bc0..e24258ead63 100644
--- a/components/raftstore/src/coprocessor/split_check/table.rs
+++ b/components/raftstore/src/coprocessor/split_check/table.rs
@@ -163,8 +163,8 @@ where
             }
             _ => panic!(
                 "start_key {} and end_key {} out of order",
-                log_wrappers::Value::key(&encoded_start_key),
-                log_wrappers::Value::key(&encoded_end_key)
+                log_wrappers::Value::key(encoded_start_key),
+                log_wrappers::Value::key(encoded_end_key)
             ),
         }
         host.add_checker(Box::new(Checker {
diff --git a/components/raftstore/src/coprocessor/split_observer.rs b/components/raftstore/src/coprocessor/split_observer.rs
index 8fad7acb790..45566722e27 100644
--- a/components/raftstore/src/coprocessor/split_observer.rs
+++ b/components/raftstore/src/coprocessor/split_observer.rs
@@ -35,13 +35,13 @@ fn is_valid_split_key(key: &[u8], index: usize, region: &Region) -> bool {
         return false;
     }
 
-    if let Err(Error::KeyNotInRegion(..)) = util::check_key_in_region_exclusive(&key, region) {
+    if let Err(Error::KeyNotInRegion(..)) = util::check_key_in_region_exclusive(key, region) {
         warn!(
             "skip invalid split key: key is not in region";
-            "key" => log_wrappers::Value::key(&key),
+            "key" => log_wrappers::Value::key(key),
             "region_id" => region.get_id(),
-            "start_key" => log_wrappers::Value::key(&region.get_start_key()),
-            "end_key" => log_wrappers::Value::key(&region.get_end_key()),
+            "start_key" => log_wrappers::Value::key(region.get_start_key()),
+            "end_key" => log_wrappers::Value::key(region.get_end_key()),
             "index" => index,
         );
         return false;
diff --git a/components/raftstore/src/lib.rs b/components/raftstore/src/lib.rs
index d78614288fa..638b3aee09f 100644
--- a/components/raftstore/src/lib.rs
+++ b/components/raftstore/src/lib.rs
@@ -6,7 +6,6 @@
 #![feature(div_duration)]
 #![feature(min_specialization)]
 #![feature(box_patterns)]
-#![feature(vecdeque_binary_search)]
 
 #[cfg(test)]
 extern crate test;
diff --git a/components/raftstore/src/store/fsm/apply.rs b/components/raftstore/src/store/fsm/apply.rs
index d862c569a26..9236ad4e987 100644
--- a/components/raftstore/src/store/fsm/apply.rs
+++ b/components/raftstore/src/store/fsm/apply.rs
@@ -1207,7 +1207,7 @@ where
         ctx.exec_ctx = Some(self.new_ctx(index, term));
         ctx.kv_wb_mut().set_save_point();
         let mut origin_epoch = None;
-        let (resp, exec_result) = match self.exec_raft_cmd(ctx, &req) {
+        let (resp, exec_result) = match self.exec_raft_cmd(ctx, req) {
             Ok(a) => {
                 ctx.kv_wb_mut().pop_save_point().unwrap();
                 if req.has_admin_request() {
@@ -1523,7 +1523,7 @@ where
                     "{} failed to write ({}, {}) to cf {}: {:?}",
                     self.tag,
                     log_wrappers::Value::key(&key),
-                    log_wrappers::Value::value(&value),
+                    log_wrappers::Value::value(value),
                     cf,
                     e
                 )
@@ -1534,7 +1534,7 @@ where
                     "{} failed to write ({}, {}): {:?}",
                     self.tag,
                     log_wrappers::Value::key(&key),
-                    log_wrappers::Value::value(&value),
+                    log_wrappers::Value::value(value),
                     e
                 );
             });
diff --git a/components/raftstore/src/store/fsm/peer.rs b/components/raftstore/src/store/fsm/peer.rs
index 4d677a20f28..bedb6267a9f 100644
--- a/components/raftstore/src/store/fsm/peer.rs
+++ b/components/raftstore/src/store/fsm/peer.rs
@@ -583,7 +583,7 @@ where
                 PeerMsg::UpdateReplicationMode => self.on_update_replication_mode(),
                 PeerMsg::Destroy(peer_id) => {
                     if self.fsm.peer.peer_id() == peer_id {
-                        match self.fsm.peer.maybe_destroy(&self.ctx) {
+                        match self.fsm.peer.maybe_destroy(self.ctx) {
                             None => self.ctx.raft_metrics.message_dropped.applying_snap += 1,
                             Some(job) => {
                                 self.handle_destroy_peer(job);
@@ -977,7 +977,7 @@ where
             if StateRole::Leader == ss.raft_state {
                 self.fsm.missing_ticks = 0;
                 self.register_split_region_check_tick();
-                self.fsm.peer.heartbeat_pd(&self.ctx);
+                self.fsm.peer.heartbeat_pd(self.ctx);
                 self.register_pd_heartbeat_tick();
             }
         }
@@ -1337,7 +1337,7 @@ where
             Either::Right(v) => v,
         };
 
-        if util::is_vote_msg(&msg.get_message())
+        if util::is_vote_msg(msg.get_message())
             || msg.get_message().get_msg_type() == MessageType::MsgTimeoutNow
         {
             if self.fsm.hibernate_state.group_state() != GroupState::Chaos {
@@ -1541,7 +1541,7 @@ where
         if util::is_epoch_stale(from_epoch, self_epoch)
             && util::find_peer(self.fsm.peer.region(), from_store_id).is_none()
         {
-            self.ctx.handle_stale_msg(&msg, self_epoch.clone(), None);
+            self.ctx.handle_stale_msg(msg, self_epoch.clone(), None);
             return true;
         }
 
@@ -1558,7 +1558,7 @@ where
                 true
             }
             cmp::Ordering::Greater => {
-                match self.fsm.peer.maybe_destroy(&self.ctx) {
+                match self.fsm.peer.maybe_destroy(self.ctx) {
                     Some(job) => {
                         info!(
                             "target peer id is larger, destroying self";
@@ -2640,7 +2640,7 @@ where
                 }
             };
 
-            let sibling_peer = util::find_peer(&sibling_region, self.store_id()).unwrap();
+            let sibling_peer = util::find_peer(sibling_region, self.store_id()).unwrap();
             let mut request = new_admin_request(sibling_region.get_id(), sibling_peer.clone());
             request
                 .mut_header()
@@ -3043,7 +3043,7 @@ where
         // If the merge succeed, all source peers are impossible in apply snapshot state
         // and must be initialized.
         // So `maybe_destroy` must succeed here.
-        let job = self.fsm.peer.maybe_destroy(&self.ctx).unwrap();
+        let job = self.fsm.peer.maybe_destroy(self.ctx).unwrap();
         self.handle_destroy_peer(job);
     }
 
@@ -3082,7 +3082,7 @@ where
 
         // Remove its source peers' metadata
         for r in &apply_result.destroyed_regions {
-            let prev = meta.region_ranges.remove(&enc_end_key(&r));
+            let prev = meta.region_ranges.remove(&enc_end_key(r));
             assert_eq!(prev, Some(r.get_id()));
             assert!(meta.regions.remove(&r.get_id()).is_some());
             meta.readers.remove(&r.get_id());
diff --git a/components/raftstore/src/store/fsm/store.rs b/components/raftstore/src/store/fsm/store.rs
index 404fbfc09aa..a12cd8aae62 100644
--- a/components/raftstore/src/store/fsm/store.rs
+++ b/components/raftstore/src/store/fsm/store.rs
@@ -1420,7 +1420,7 @@ pub fn create_raft_batch_system<EK: KvEngine, ER: RaftEngine>(
     cfg: &Config,
 ) -> (RaftRouter<EK, ER>, RaftBatchSystem<EK, ER>) {
     let (store_tx, store_fsm) = StoreFsm::new(cfg);
-    let (apply_router, apply_system) = create_apply_batch_system(&cfg);
+    let (apply_router, apply_system) = create_apply_batch_system(cfg);
     let (router, system) =
         batch_system::create_system(&cfg.store_batch_system, store_tx, store_fsm);
     let raft_router = RaftRouter { router };
@@ -1699,7 +1699,7 @@ impl<'a, EK: KvEngine, ER: RaftEngine, T: Transport> StoreFsmDelegate<'a, EK, ER
             pending_create_peers.insert(region_id, (msg.get_to_peer().get_id(), false));
         }
 
-        let res = self.maybe_create_peer_internal(region_id, &msg, is_local_first);
+        let res = self.maybe_create_peer_internal(region_id, msg, is_local_first);
         // If failed, i.e. Err or Ok(false), remove this peer data from `pending_create_peers`.
         if res.as_ref().map_or(true, |b| !*b) && is_local_first {
             let mut pending_create_peers = self.ctx.pending_create_peers.lock().unwrap();
@@ -1755,7 +1755,7 @@ impl<'a, EK: KvEngine, ER: RaftEngine, T: Transport> StoreFsmDelegate<'a, EK, ER
             Excluded(data_key(msg.get_start_key())),
             Unbounded::<Vec<u8>>,
         )) {
-            let exist_region = &meta.regions[&id];
+            let exist_region = &meta.regions[id];
             if enc_start_key(exist_region) >= data_end_key(msg.get_end_key()) {
                 break;
             }
diff --git a/components/raftstore/src/store/msg.rs b/components/raftstore/src/store/msg.rs
index 49373dbc37d..29f7cb96e88 100644
--- a/components/raftstore/src/store/msg.rs
+++ b/components/raftstore/src/store/msg.rs
@@ -363,7 +363,7 @@ impl<EK: KvEngine> fmt::Debug for CasualMessage<EK> {
                 fmt,
                 "ComputeHashResult [index: {}, context: {}, hash: {}]",
                 index,
-                log_wrappers::Value::key(&context),
+                log_wrappers::Value::key(context),
                 escape(hash)
             ),
             CasualMessage::SplitRegion {
diff --git a/components/raftstore/src/store/peer.rs b/components/raftstore/src/store/peer.rs
index 5f0de36ee43..12eeba6284e 100644
--- a/components/raftstore/src/store/peer.rs
+++ b/components/raftstore/src/store/peer.rs
@@ -3213,10 +3213,7 @@ where
                 self.term()
             ));
         }
-        if let Some(index) = self
-            .cmd_epoch_checker
-            .propose_check_epoch(&req, self.term())
-        {
+        if let Some(index) = self.cmd_epoch_checker.propose_check_epoch(req, self.term()) {
             return Ok(Either::Right(index));
         }
 
diff --git a/components/raftstore/src/store/region_snapshot.rs b/components/raftstore/src/store/region_snapshot.rs
index 732ce004950..576595a2b61 100644
--- a/components/raftstore/src/store/region_snapshot.rs
+++ b/components/raftstore/src/store/region_snapshot.rs
@@ -231,14 +231,14 @@ where
             set_panic_mark();
             panic!(
                 "failed to get value of key {} in region {}: {:?}",
-                log_wrappers::Value::key(&key),
+                log_wrappers::Value::key(key),
                 self.region.get_id(),
                 e,
             );
         } else {
             error!(
                 "failed to get value of key in cf";
-                "key" => log_wrappers::Value::key(&key),
+                "key" => log_wrappers::Value::key(key),
                 "region" => self.region.get_id(),
                 "cf" => cf,
                 "error" => ?e,
diff --git a/components/raftstore/src/store/snap.rs b/components/raftstore/src/store/snap.rs
index d091b5be48f..2aeeacbe7ab 100644
--- a/components/raftstore/src/store/snap.rs
+++ b/components/raftstore/src/store/snap.rs
@@ -232,7 +232,7 @@ fn calc_checksum_and_size(
     let (checksum, size) = if let Some(mgr) = encryption_key_manager {
         // Crc32 and file size need to be calculated based on decrypted contents.
         let file_name = path.to_str().unwrap();
-        let mut r = snap_io::get_decrypter_reader(file_name, &mgr)?;
+        let mut r = snap_io::get_decrypter_reader(file_name, mgr)?;
         calc_crc32_and_size(&mut r)?
     } else {
         (calc_crc32(path)?, get_file_size(path)?)
@@ -1800,7 +1800,7 @@ pub mod tests {
             .prefix("test-snap-file-db-src")
             .tempdir()
             .unwrap();
-        let db = get_db(&src_db_dir.path(), db_opt.clone(), None).unwrap();
+        let db = get_db(src_db_dir.path(), db_opt.clone(), None).unwrap();
         let snapshot = db.snapshot();
 
         let src_dir = Builder::new()
@@ -1917,7 +1917,7 @@ pub mod tests {
             .prefix("test-snap-validation-db")
             .tempdir()
             .unwrap();
-        let db = get_db(&db_dir.path(), None, None).unwrap();
+        let db = get_db(db_dir.path(), None, None).unwrap();
         let snapshot = db.snapshot();
 
         let dir = Builder::new()
@@ -2084,7 +2084,7 @@ pub mod tests {
             .prefix("test-snap-corruption-db")
             .tempdir()
             .unwrap();
-        let db: KvTestEngine = open_test_db(&db_dir.path(), None, None).unwrap();
+        let db: KvTestEngine = open_test_db(db_dir.path(), None, None).unwrap();
         let snapshot = db.snapshot();
 
         let dir = Builder::new()
@@ -2150,7 +2150,7 @@ pub mod tests {
             .prefix("test-snap-corruption-dst-db")
             .tempdir()
             .unwrap();
-        let dst_db: KvTestEngine = open_test_empty_db(&dst_db_dir.path(), None, None).unwrap();
+        let dst_db: KvTestEngine = open_test_empty_db(dst_db_dir.path(), None, None).unwrap();
         let options = ApplyOptions {
             db: dst_db,
             region,
@@ -2173,7 +2173,7 @@ pub mod tests {
             .prefix("test-snapshot-corruption-meta-db")
             .tempdir()
             .unwrap();
-        let db: KvTestEngine = open_test_db(&db_dir.path(), None, None).unwrap();
+        let db: KvTestEngine = open_test_db(db_dir.path(), None, None).unwrap();
         let snapshot = db.snapshot();
 
         let dir = Builder::new()
@@ -2271,7 +2271,7 @@ pub mod tests {
             .prefix("test-snap-mgr-delete-temp-files-v2-db")
             .tempdir()
             .unwrap();
-        let db: KvTestEngine = open_test_db(&db_dir.path(), None, None).unwrap();
+        let db: KvTestEngine = open_test_db(db_dir.path(), None, None).unwrap();
         let snapshot = db.snapshot();
         let key1 = SnapKey::new(1, 1, 1);
         let mgr_core = create_manager_core(&path);
@@ -2351,7 +2351,7 @@ pub mod tests {
             .prefix("test-snap-deletion-on-registry-src-db")
             .tempdir()
             .unwrap();
-        let db: KvTestEngine = open_test_db(&src_db_dir.path(), None, None).unwrap();
+        let db: KvTestEngine = open_test_db(src_db_dir.path(), None, None).unwrap();
         let snapshot = db.snapshot();
 
         let key = SnapKey::new(1, 1, 1);
@@ -2500,7 +2500,7 @@ pub mod tests {
             .prefix("test_snap_temp_file_delete_kv")
             .tempdir()
             .unwrap();
-        let engine = open_test_db(&kv_temp_dir.path(), None, None).unwrap();
+        let engine = open_test_db(kv_temp_dir.path(), None, None).unwrap();
         let sst_path = src_mgr.get_temp_path_for_ingest();
         let mut writer = <KvTestEngine as SstExt>::SstWriterBuilder::new()
             .set_db(&engine)
@@ -2519,7 +2519,7 @@ pub mod tests {
 
     #[test]
     fn test_build_with_encryption() {
-        let (_enc_dir, key_path, dict_path) = create_enc_dir(&"test_build_with_encryption_enc");
+        let (_enc_dir, key_path, dict_path) = create_enc_dir("test_build_with_encryption_enc");
         let enc_cfg = EncryptionConfig {
             data_encryption_method: EncryptionMethod::Aes128Ctr,
             master_key: MasterKeyConfig::File {
diff --git a/components/raftstore/src/store/snap/io.rs b/components/raftstore/src/store/snap/io.rs
index bd71c3bc431..71d7f780b15 100644
--- a/components/raftstore/src/store/snap/io.rs
+++ b/components/raftstore/src/store/snap/io.rs
@@ -165,7 +165,7 @@ where
 
     let mut wb = db.write_batch();
     let mut write_to_db = |batch: &mut Vec<(Vec<u8>, Vec<u8>)>| -> Result<(), EngineError> {
-        batch.iter().try_for_each(|(k, v)| wb.put_cf(cf, &k, &v))?;
+        batch.iter().try_for_each(|(k, v)| wb.put_cf(cf, k, v))?;
         wb.write()?;
         wb.clear();
         callback(batch);
@@ -211,7 +211,7 @@ where
     E: KvEngine,
 {
     let builder = E::SstWriterBuilder::new()
-        .set_db(&engine)
+        .set_db(engine)
         .set_cf(cf)
         .set_compression_type(Some(SstCompressionType::Zstd));
     let writer = box_try!(builder.build(path));
@@ -264,21 +264,21 @@ mod tests {
         for db_creater in db_creaters {
             for db_opt in vec![None, Some(gen_db_options_with_encryption())] {
                 let dir = Builder::new().prefix("test-snap-cf-db").tempdir().unwrap();
-                let db: KvTestEngine = db_creater(&dir.path(), db_opt.clone(), None).unwrap();
+                let db: KvTestEngine = db_creater(dir.path(), db_opt.clone(), None).unwrap();
                 // Collect keys via the key_callback into a collection.
                 let mut applied_keys: HashMap<_, Vec<_>> = HashMap::new();
                 let dir1 = Builder::new()
                     .prefix("test-snap-cf-db-apply")
                     .tempdir()
                     .unwrap();
-                let db1: KvTestEngine = open_test_empty_db(&dir1.path(), db_opt, None).unwrap();
+                let db1: KvTestEngine = open_test_empty_db(dir1.path(), db_opt, None).unwrap();
 
                 let snap = db.snapshot();
                 for cf in SNAPSHOT_CFS {
                     let snap_cf_dir = Builder::new().prefix("test-snap-cf").tempdir().unwrap();
                     let plain_file_path = snap_cf_dir.path().join("plain");
                     let stats = build_plain_cf_file::<KvTestEngine>(
-                        &plain_file_path.to_str().unwrap(),
+                        plain_file_path.to_str().unwrap(),
                         None,
                         &snap,
                         cf,
@@ -296,7 +296,7 @@ mod tests {
 
                     let detector = TestStaleDetector {};
                     apply_plain_cf_file(
-                        &plain_file_path.to_str().unwrap(),
+                        plain_file_path.to_str().unwrap(),
                         None,
                         &detector,
                         &db1,
@@ -343,12 +343,12 @@ mod tests {
         for db_creater in db_creaters {
             for db_opt in vec![None, Some(gen_db_options_with_encryption())] {
                 let dir = Builder::new().prefix("test-snap-cf-db").tempdir().unwrap();
-                let db = db_creater(&dir.path(), db_opt.clone(), None).unwrap();
+                let db = db_creater(dir.path(), db_opt.clone(), None).unwrap();
 
                 let snap_cf_dir = Builder::new().prefix("test-snap-cf").tempdir().unwrap();
                 let sst_file_path = snap_cf_dir.path().join("sst");
                 let stats = build_sst_cf_file::<KvTestEngine>(
-                    &sst_file_path.to_str().unwrap(),
+                    sst_file_path.to_str().unwrap(),
                     &db,
                     &db.snapshot(),
                     CF_DEFAULT,
@@ -369,8 +369,8 @@ mod tests {
                     .prefix("test-snap-cf-db-apply")
                     .tempdir()
                     .unwrap();
-                let db1: KvTestEngine = open_test_empty_db(&dir1.path(), db_opt, None).unwrap();
-                apply_sst_cf_file(&sst_file_path.to_str().unwrap(), &db1, CF_DEFAULT).unwrap();
+                let db1: KvTestEngine = open_test_empty_db(dir1.path(), db_opt, None).unwrap();
+                apply_sst_cf_file(sst_file_path.to_str().unwrap(), &db1, CF_DEFAULT).unwrap();
                 assert_eq_db(&db, &db1);
             }
         }
diff --git a/components/raftstore/src/store/worker/pd.rs b/components/raftstore/src/store/worker/pd.rs
index 91244d434cc..ab3ce341438 100644
--- a/components/raftstore/src/store/worker/pd.rs
+++ b/components/raftstore/src/store/worker/pd.rs
@@ -255,7 +255,7 @@ where
                 f,
                 "ask split region {} with key {}",
                 region.get_id(),
-                log_wrappers::Value::key(&split_key),
+                log_wrappers::Value::key(split_key),
             ),
             Task::AutoSplit { ref split_infos } => {
                 write!(f, "auto split split regions, num is {}", split_infos.len(),)
diff --git a/components/raftstore/src/store/worker/read.rs b/components/raftstore/src/store/worker/read.rs
index 5043d20a5c1..aa11ebb1339 100644
--- a/components/raftstore/src/store/worker/read.rs
+++ b/components/raftstore/src/store/worker/read.rs
@@ -603,7 +603,7 @@ where
             Ok(None) => self.redirect(RaftCommand::new(req, cb)),
             Err(e) => {
                 let mut response = cmd_resp::new_error(e);
-                if let Some(ref delegate) = self.delegates.get(&req.get_header().get_region_id()) {
+                if let Some(delegate) = self.delegates.get(&req.get_header().get_region_id()) {
                     cmd_resp::bind_term(&mut response, delegate.term);
                 }
                 cb.invoke_read(ReadResponse {
diff --git a/components/raftstore/src/store/worker/region.rs b/components/raftstore/src/store/worker/region.rs
index 3ff4f930e54..703957963da 100644
--- a/components/raftstore/src/store/worker/region.rs
+++ b/components/raftstore/src/store/worker/region.rs
@@ -99,8 +99,8 @@ impl<S> Display for Task<S> {
                 f,
                 "Destroy {} [{}, {})",
                 region_id,
-                log_wrappers::Value::key(&start_key),
-                log_wrappers::Value::key(&end_key)
+                log_wrappers::Value::key(start_key),
+                log_wrappers::Value::key(end_key)
             ),
         }
     }
@@ -186,12 +186,12 @@ impl PendingDeleteRanges {
     ///
     /// Before an insert is called, it must call drain_overlap_ranges to clean the overlapping range.
     fn insert(&mut self, region_id: u64, start_key: &[u8], end_key: &[u8], stale_sequence: u64) {
-        if !self.find_overlap_ranges(&start_key, &end_key).is_empty() {
+        if !self.find_overlap_ranges(start_key, end_key).is_empty() {
             panic!(
                 "[region {}] register deleting data in [{}, {}) failed due to overlap",
                 region_id,
-                log_wrappers::Value::key(&start_key),
-                log_wrappers::Value::key(&end_key),
+                log_wrappers::Value::key(start_key),
+                log_wrappers::Value::key(end_key),
             );
         }
         let info = StalePeerInfo {
@@ -436,13 +436,13 @@ where
     /// Cleans up the data within the range.
     fn cleanup_range(&self, ranges: &[Range]) -> Result<()> {
         self.engine
-            .delete_all_in_range(DeleteStrategy::DeleteFiles, &ranges)
+            .delete_all_in_range(DeleteStrategy::DeleteFiles, ranges)
             .unwrap_or_else(|e| {
                 error!("failed to delete files in range"; "err" => %e);
             });
         self.delete_all_in_range(ranges)?;
         self.engine
-            .delete_all_in_range(DeleteStrategy::DeleteBlobs, &ranges)
+            .delete_all_in_range(DeleteStrategy::DeleteBlobs, ranges)
             .unwrap_or_else(|e| {
                 error!("failed to delete files in range"; "err" => %e);
             });
diff --git a/components/raftstore/src/store/worker/split_controller.rs b/components/raftstore/src/store/worker/split_controller.rs
index 60952bf55fc..520b40a64b9 100644
--- a/components/raftstore/src/store/worker/split_controller.rs
+++ b/components/raftstore/src/store/worker/split_controller.rs
@@ -56,7 +56,7 @@ where
     let mut pre_sum = vec![];
     let mut sum = 0;
     for item in iter {
-        sum += read(&item);
+        sum += read(item);
         pre_sum.push(sum);
     }
     pre_sum
@@ -208,7 +208,7 @@ impl Recorder {
         let mut samples: Vec<Sample> = self.convert(sampled_key_ranges);
         for key_ranges in &self.key_ranges {
             for key_range in key_ranges {
-                Recorder::sample(&mut samples, &key_range);
+                Recorder::sample(&mut samples, key_range);
             }
         }
         Recorder::split_key(
diff --git a/components/resolved_ts/src/endpoint.rs b/components/resolved_ts/src/endpoint.rs
index cffae0238ba..5b57df59f31 100644
--- a/components/resolved_ts/src/endpoint.rs
+++ b/components/resolved_ts/src/endpoint.rs
@@ -474,7 +474,7 @@ where
 
         let mut min_ts = TimeStamp::max();
         for region_id in regions.iter() {
-            if let Some(observe_region) = self.regions.get_mut(&region_id) {
+            if let Some(observe_region) = self.regions.get_mut(region_id) {
                 if let ResolverStatus::Ready = observe_region.resolver_status {
                     let resolved_ts = observe_region.resolver.resolve(ts);
                     if resolved_ts < min_ts {
diff --git a/components/server/src/raft_engine_switch.rs b/components/server/src/raft_engine_switch.rs
index 8e57bd4db1f..db2064ee11f 100644
--- a/components/server/src/raft_engine_switch.rs
+++ b/components/server/src/raft_engine_switch.rs
@@ -97,7 +97,7 @@ pub fn check_and_dump_raft_db(
     let mut raft_db_opts = config_raftdb.build_opt();
     raft_db_opts.set_env(env.clone());
     let raft_db_cf_opts = config_raftdb.build_cf_opts(&None);
-    let db = engine_rocks::raw_util::new_engine_opt(&raftdb_path, raft_db_opts, raft_db_cf_opts)
+    let db = engine_rocks::raw_util::new_engine_opt(raftdb_path, raft_db_opts, raft_db_cf_opts)
         .unwrap_or_else(|s| fatal!("failed to create origin raft db: {}", s));
     let src_engine = RocksEngine::from_db(Arc::new(db));
 
@@ -176,12 +176,12 @@ fn run_dump_raftdb_worker(
                             match suffix {
                                 keys::RAFT_LOG_SUFFIX => {
                                     let mut entry = Entry::default();
-                                    entry.merge_from_bytes(&value)?;
+                                    entry.merge_from_bytes(value)?;
                                     entries.push(entry);
                                 }
                                 keys::RAFT_STATE_SUFFIX => {
                                     let mut state = RaftLocalState::default();
-                                    state.merge_from_bytes(&value)?;
+                                    state.merge_from_bytes(value)?;
                                     batch.put_raft_state(region_id, &state).unwrap();
                                     // Assume that we always scan entry first and raft state at the end.
                                     batch
diff --git a/components/server/src/setup.rs b/components/server/src/setup.rs
index 8eacc0ab9b8..547f1cd8daa 100644
--- a/components/server/src/setup.rs
+++ b/components/server/src/setup.rs
@@ -58,7 +58,7 @@ fn make_engine_log_path(path: &str, sub_path: &str, filename: &str) -> String {
     config::ensure_dir_exist(path).unwrap_or_else(|e| {
         fatal!("failed to create engine log dir: {}", e);
     });
-    config::canonicalize_log_dir(&path, filename).unwrap_or_else(|e| {
+    config::canonicalize_log_dir(path, filename).unwrap_or_else(|e| {
         fatal!("failed to canonicalize engine log dir {:?}: {}", path, e);
     })
 }
@@ -283,7 +283,7 @@ pub fn validate_and_persist_config(config: &mut TiKvConfig, persist: bool) {
     }
 
     if persist {
-        if let Err(e) = persist_config(&config) {
+        if let Err(e) = persist_config(config) {
             fatal!("persist critical config failed: {}", e);
         }
     }
diff --git a/components/sst_importer/src/errors.rs b/components/sst_importer/src/errors.rs
index 54d4482ec4b..1eafc0f3d24 100644
--- a/components/sst_importer/src/errors.rs
+++ b/components/sst_importer/src/errors.rs
@@ -88,7 +88,8 @@ pub enum Error {
 
     #[error(
         "{what} has wrong prefix: key {} does not start with {}",
-        log_wrappers::Value::key(&key), log_wrappers::Value::key(&prefix)
+        log_wrappers::Value::key(key),
+        log_wrappers::Value::key(prefix)
     )]
     WrongKeyPrefix {
         what: &'static str,
diff --git a/components/sst_importer/src/import_file.rs b/components/sst_importer/src/import_file.rs
index 659a270de8f..7cf5c6da0fc 100644
--- a/components/sst_importer/src/import_file.rs
+++ b/components/sst_importer/src/import_file.rs
@@ -275,7 +275,7 @@ impl ImportDir {
         let path = self.join(meta)?;
         let path_str = path.save.to_str().unwrap();
         let env = get_env(key_manager, get_io_rate_limiter())?;
-        let sst_reader = RocksSstReader::open_with_env(&path_str, Some(env))?;
+        let sst_reader = RocksSstReader::open_with_env(path_str, Some(env))?;
         sst_reader.verify_checksum()?;
         // TODO: check the length and crc32 of ingested file.
         let meta_info = sst_reader.sst_meta_info(meta.to_owned());
diff --git a/components/sst_importer/src/sst_importer.rs b/components/sst_importer/src/sst_importer.rs
index 3b6721315c1..208b6c16920 100644
--- a/components/sst_importer/src/sst_importer.rs
+++ b/components/sst_importer/src/sst_importer.rs
@@ -351,7 +351,7 @@ impl SSTImporter {
 
         while iter.valid()? {
             let old_key = keys::origin_key(iter.key());
-            if is_after_end_bound(&old_key, &range_end) {
+            if is_after_end_bound(old_key, &range_end) {
                 break;
             }
             if !old_key.starts_with(old_prefix) {
@@ -429,7 +429,7 @@ impl SSTImporter {
         default_meta.set_cf_name(CF_DEFAULT.to_owned());
         let default_path = self.dir.join(&default_meta)?;
         let default = E::SstWriterBuilder::new()
-            .set_db(&db)
+            .set_db(db)
             .set_cf(CF_DEFAULT)
             .set_compression_type(self.compression_types.get(CF_DEFAULT).copied())
             .build(default_path.temp.to_str().unwrap())
@@ -439,7 +439,7 @@ impl SSTImporter {
         write_meta.set_cf_name(CF_WRITE.to_owned());
         let write_path = self.dir.join(&write_meta)?;
         let write = E::SstWriterBuilder::new()
-            .set_db(&db)
+            .set_db(db)
             .set_cf(CF_WRITE)
             .set_compression_type(self.compression_types.get(CF_WRITE).copied())
             .build(write_path.temp.to_str().unwrap())
@@ -464,7 +464,7 @@ impl SSTImporter {
         meta.set_cf_name(CF_DEFAULT.to_owned());
         let default_path = self.dir.join(&meta)?;
         let default = E::SstWriterBuilder::new()
-            .set_db(&db)
+            .set_db(db)
             .set_cf(CF_DEFAULT)
             .build(default_path.temp.to_str().unwrap())
             .unwrap();
diff --git a/components/test_backup/src/lib.rs b/components/test_backup/src/lib.rs
index c34c492b7f2..684558fdb3c 100644
--- a/components/test_backup/src/lib.rs
+++ b/components/test_backup/src/lib.rs
@@ -76,8 +76,8 @@ impl TestSuite {
             let sim = cluster.sim.rl();
             let backup_endpoint = backup::Endpoint::new(
                 *id,
-                sim.storages[&id].clone(),
-                sim.region_info_accessors[&id].clone(),
+                sim.storages[id].clone(),
+                sim.region_info_accessors[id].clone(),
                 engines.kv.as_inner().clone(),
                 BackupConfig {
                     num_threads: 4,
diff --git a/components/test_coprocessor/src/fixture.rs b/components/test_coprocessor/src/fixture.rs
index 51d33946576..3f5d4e7139f 100644
--- a/components/test_coprocessor/src/fixture.rs
+++ b/components/test_coprocessor/src/fixture.rs
@@ -73,7 +73,7 @@ pub fn init_data_with_details<E: Engine>(
     store.begin();
     for &(id, name, count) in vals {
         store
-            .insert_into(&tbl)
+            .insert_into(tbl)
             .set(&tbl["id"], Datum::I64(id))
             .set(&tbl["name"], name.map(str::as_bytes).into())
             .set(&tbl["count"], Datum::I64(count))
diff --git a/components/test_raftstore/src/cluster.rs b/components/test_raftstore/src/cluster.rs
index c0617fb6b4e..ba61cda4dcb 100644
--- a/components/test_raftstore/src/cluster.rs
+++ b/components/test_raftstore/src/cluster.rs
@@ -336,11 +336,11 @@ impl<T: Simulator> Cluster<T> {
     }
 
     pub fn get_engine(&self, node_id: u64) -> Arc<DB> {
-        Arc::clone(&self.engines[&node_id].kv.as_inner())
+        Arc::clone(self.engines[&node_id].kv.as_inner())
     }
 
     pub fn get_raft_engine(&self, node_id: u64) -> Arc<DB> {
-        Arc::clone(&self.engines[&node_id].raft.as_inner())
+        Arc::clone(self.engines[&node_id].raft.as_inner())
     }
 
     pub fn get_all_engines(&self, node_id: u64) -> Engines<RocksEngine, RocksEngine> {
@@ -603,11 +603,11 @@ impl<T: Simulator> Cluster<T> {
         for (&id, engines) in &self.engines {
             let peer = new_peer(id, id);
             region.mut_peers().push(peer.clone());
-            bootstrap_store(&engines, self.id(), id).unwrap();
+            bootstrap_store(engines, self.id(), id).unwrap();
         }
 
         for engines in self.engines.values() {
-            prepare_bootstrap_cluster(&engines, &region)?;
+            prepare_bootstrap_cluster(engines, &region)?;
         }
 
         self.bootstrap_cluster(region);
@@ -627,7 +627,7 @@ impl<T: Simulator> Cluster<T> {
         }
 
         for (&id, engines) in &self.engines {
-            bootstrap_store(&engines, self.id(), id).unwrap();
+            bootstrap_store(engines, self.id(), id).unwrap();
         }
 
         let node_id = 1;
diff --git a/components/test_raftstore/src/pd.rs b/components/test_raftstore/src/pd.rs
index 8876cb14c52..af635ce4222 100644
--- a/components/test_raftstore/src/pd.rs
+++ b/components/test_raftstore/src/pd.rs
@@ -134,7 +134,7 @@ impl Operator {
         match *self {
             Operator::AddPeer { ref peer, .. } => {
                 if let Either::Left(ref peer) = *peer {
-                    let conf_change_type = if is_learner(&peer) {
+                    let conf_change_type = if is_learner(peer) {
                         ConfChangeType::AddLearnerNode
                     } else {
                         ConfChangeType::AddNode
@@ -184,7 +184,7 @@ impl Operator {
             } => {
                 let mut cps = Vec::with_capacity(to_add_peers.len() + remove_peers.len());
                 for peer in to_add_peers.iter() {
-                    let conf_change_type = if is_learner(&peer) {
+                    let conf_change_type = if is_learner(peer) {
                         ConfChangeType::AddLearnerNode
                     } else {
                         ConfChangeType::AddNode
diff --git a/components/test_storage/src/assert_storage.rs b/components/test_storage/src/assert_storage.rs
index 4dd849d9d70..da38ba881a2 100644
--- a/components/test_storage/src/assert_storage.rs
+++ b/components/test_storage/src/assert_storage.rs
@@ -260,7 +260,7 @@ impl<E: Engine> AssertionStorage<E> {
     pub fn batch_get_command_ok(&self, keys: &[&[u8]], ts: u64, expect: Vec<&[u8]>) {
         let result: Vec<Option<Vec<u8>>> = self
             .store
-            .batch_get_command(self.ctx.clone(), &keys, ts)
+            .batch_get_command(self.ctx.clone(), keys, ts)
             .unwrap()
             .into_iter()
             .collect();
@@ -634,12 +634,12 @@ impl<E: Engine> AssertionStorage<E> {
         let start_key = if start_key.is_empty() {
             None
         } else {
-            Some(Key::from_raw(&start_key))
+            Some(Key::from_raw(start_key))
         };
         let end_key = if end_key.is_empty() {
             None
         } else {
-            Some(Key::from_raw(&end_key))
+            Some(Key::from_raw(end_key))
         };
 
         assert_eq!(
diff --git a/components/tidb_query_aggr/src/impl_max_min.rs b/components/tidb_query_aggr/src/impl_max_min.rs
index 13d94a59c7f..0070224a7d9 100644
--- a/components/tidb_query_aggr/src/impl_max_min.rs
+++ b/components/tidb_query_aggr/src/impl_max_min.rs
@@ -184,7 +184,7 @@ where
             return Ok(());
         }
 
-        if C::sort_compare(&self.extremum.as_ref().unwrap(), &value.as_ref().unwrap())? == E::ORD {
+        if C::sort_compare(self.extremum.as_ref().unwrap(), value.as_ref().unwrap())? == E::ORD {
             self.extremum = value.map(|x| x.into_owned_value());
         }
         Ok(())
@@ -257,11 +257,7 @@ where
 
         if value.is_some()
             && (self.extremum.is_none()
-                || extreme_ref
-                    .unwrap()
-                    .as_str()?
-                    .cmp(&value.unwrap().as_str()?)
-                    == E::ORD)
+                || extreme_ref.unwrap().as_str()?.cmp(value.unwrap().as_str()?) == E::ORD)
         {
             self.extremum = value.map(|x| x.into_owned_value());
         }
@@ -912,7 +908,7 @@ mod tests {
                     &mut ctx,
                     &src_schema,
                     columns,
-                    &logical_rows,
+                    logical_rows,
                     logical_rows.len(),
                 )
                 .unwrap();
@@ -929,7 +925,7 @@ mod tests {
                     &mut ctx,
                     &src_schema,
                     columns,
-                    &logical_rows,
+                    logical_rows,
                     logical_rows.len(),
                 )
                 .unwrap();
diff --git a/components/tidb_query_aggr/src/parser.rs b/components/tidb_query_aggr/src/parser.rs
index c90cdfa51b0..e76095988da 100644
--- a/components/tidb_query_aggr/src/parser.rs
+++ b/components/tidb_query_aggr/src/parser.rs
@@ -44,7 +44,7 @@ pub trait AggrDefinitionParser {
         let child = aggr_def.take_children().into_iter().next().unwrap();
         let exp = RpnExpressionBuilder::build_from_expr_tree(child, ctx, src_schema.len())?;
 
-        Self::parse_rpn(&self, aggr_def, exp, ctx, src_schema, out_schema, out_exp)
+        Self::parse_rpn(self, aggr_def, exp, ctx, src_schema, out_schema, out_exp)
     }
 
     #[inline]
diff --git a/components/tidb_query_codegen/src/rpn_function.rs b/components/tidb_query_codegen/src/rpn_function.rs
index ebedc07763c..7a34723f5a7 100644
--- a/components/tidb_query_codegen/src/rpn_function.rs
+++ b/components/tidb_query_codegen/src/rpn_function.rs
@@ -925,7 +925,7 @@ impl VargsRpnFn {
         }
 
         let fn_arg = item_fn.sig.inputs.iter().nth(attr.captures.len()).unwrap();
-        let arg_type = Self::get_args_type(&attr, &fn_arg)?;
+        let arg_type = Self::get_args_type(&attr, fn_arg)?;
         let arg_type_anonymous = arg_type.eval_type.get_type_with_lifetime(quote! { '_ });
 
         let ret_type = if attr.writer {
@@ -1343,7 +1343,7 @@ impl NormalRpnFn {
             .skip(attr.captures.len())
             .take(take_cnt);
         for fn_arg in fn_args {
-            let arg_type = Self::get_arg_type(&attr, &fn_arg)?;
+            let arg_type = Self::get_arg_type(&attr, fn_arg)?;
             arg_types.push(arg_type.eval_type.get_type_with_lifetime(quote! { 'arg_ }));
             arg_types_anonymous.push(arg_type.eval_type.get_type_with_lifetime(quote! { '_ }));
             arg_types_no_ref.push(arg_type.eval_type.get_type_with_lifetime(quote! {}));
diff --git a/components/tidb_query_datatype/src/codec/chunk/column.rs b/components/tidb_query_datatype/src/codec/chunk/column.rs
index 21ee6c096c4..8809bafff47 100644
--- a/components/tidb_query_datatype/src/codec/chunk/column.rs
+++ b/components/tidb_query_datatype/src/codec/chunk/column.rs
@@ -195,7 +195,7 @@ impl Column {
                             col.append_null();
                         }
                         Some(val) => {
-                            col.append_decimal(&val)?;
+                            col.append_decimal(val)?;
                         }
                     }
                 }
@@ -207,7 +207,7 @@ impl Column {
                             col.append_null();
                         }
                         Some(val) => {
-                            col.append_bytes(&val)?;
+                            col.append_bytes(val)?;
                         }
                     }
                 }
diff --git a/components/tidb_query_datatype/src/codec/collation/mod.rs b/components/tidb_query_datatype/src/codec/collation/mod.rs
index 430112bf916..d1559e56178 100644
--- a/components/tidb_query_datatype/src/codec/collation/mod.rs
+++ b/components/tidb_query_datatype/src/codec/collation/mod.rs
@@ -156,7 +156,7 @@ where
 {
     #[inline]
     fn eq(&self, other: &Self) -> bool {
-        C::sort_compare(&self.inner.as_ref(), &other.inner.as_ref()).unwrap()
+        C::sort_compare(self.inner.as_ref(), other.inner.as_ref()).unwrap()
             == std::cmp::Ordering::Equal
     }
 }
@@ -169,7 +169,7 @@ where
 {
     #[inline]
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        C::sort_compare(&self.inner.as_ref(), &other.inner.as_ref()).ok()
+        C::sort_compare(self.inner.as_ref(), other.inner.as_ref()).ok()
     }
 }
 
@@ -179,7 +179,7 @@ where
 {
     #[inline]
     fn cmp(&self, other: &Self) -> Ordering {
-        C::sort_compare(&self.inner.as_ref(), &other.inner.as_ref()).unwrap()
+        C::sort_compare(self.inner.as_ref(), other.inner.as_ref()).unwrap()
     }
 }
 
diff --git a/components/tidb_query_datatype/src/codec/convert.rs b/components/tidb_query_datatype/src/codec/convert.rs
index f9f1f35a8a2..f03af093041 100644
--- a/components/tidb_query_datatype/src/codec/convert.rs
+++ b/components/tidb_query_datatype/src/codec/convert.rs
@@ -979,7 +979,7 @@ fn exp_float_str_to_int_str<'a>(
     let int_cnt: i64;
     match dot_idx {
         None => {
-            digits.extend_from_slice(&valid_float[..e_idx].as_bytes());
+            digits.extend_from_slice(valid_float[..e_idx].as_bytes());
             // if digits.len() > i64::MAX,
             // then the input str has at least 9223372036854775808 chars,
             // which make the str >= 8388608.0 TB,
@@ -987,9 +987,9 @@ fn exp_float_str_to_int_str<'a>(
             int_cnt = digits.len() as i64;
         }
         Some(dot_idx) => {
-            digits.extend_from_slice(&valid_float[..dot_idx].as_bytes());
+            digits.extend_from_slice(valid_float[..dot_idx].as_bytes());
             int_cnt = digits.len() as i64;
-            digits.extend_from_slice(&valid_float[(dot_idx + 1)..e_idx].as_bytes());
+            digits.extend_from_slice(valid_float[(dot_idx + 1)..e_idx].as_bytes());
         }
     }
     // make `digits` immutable
diff --git a/components/tidb_query_datatype/src/codec/data_type/chunked_vec_enum.rs b/components/tidb_query_datatype/src/codec/data_type/chunked_vec_enum.rs
index e9f5c697ecd..c27068b789f 100644
--- a/components/tidb_query_datatype/src/codec/data_type/chunked_vec_enum.rs
+++ b/components/tidb_query_datatype/src/codec/data_type/chunked_vec_enum.rs
@@ -135,7 +135,7 @@ impl<'a> ChunkRef<'a, EnumRef<'a>> for &'a ChunkedVecEnum {
     }
 
     fn get_bit_vec(self) -> &'a BitVec {
-        &self.values.get_bit_vec()
+        self.values.get_bit_vec()
     }
 
     #[inline]
diff --git a/components/tidb_query_datatype/src/codec/data_type/mod.rs b/components/tidb_query_datatype/src/codec/data_type/mod.rs
index 2191a4595ba..340e3d61d00 100644
--- a/components/tidb_query_datatype/src/codec/data_type/mod.rs
+++ b/components/tidb_query_datatype/src/codec/data_type/mod.rs
@@ -407,7 +407,7 @@ impl<'a, T: Evaluable + EvaluableRet> EvaluableRef<'a> for &'a T {
 
     #[inline]
     fn from_owned_value(value: &'a T) -> Self {
-        &value
+        value
     }
 }
 
diff --git a/components/tidb_query_datatype/src/codec/data_type/scalar.rs b/components/tidb_query_datatype/src/codec/data_type/scalar.rs
index f5418584da2..08c1501e664 100644
--- a/components/tidb_query_datatype/src/codec/data_type/scalar.rs
+++ b/components/tidb_query_datatype/src/codec/data_type/scalar.rs
@@ -259,7 +259,7 @@ impl<'a> ScalarValueRef<'a> {
                     None => {
                         output.write_evaluable_datum_null()?;
                     }
-                    Some(ref val) => {
+                    Some(val) => {
                         output.write_evaluable_datum_bytes(val)?;
                     }
                 }
@@ -343,7 +343,7 @@ impl<'a> ScalarValueRef<'a> {
             TT = [Real, Decimal, DateTime, Duration, Json, Enum],
             match (self, other) {
                 (ScalarValueRef::TT(v1), ScalarValueRef::TT(v2)) => v1.cmp(v2),
-                (ScalarValueRef::Int(v1), ScalarValueRef::Int(v2)) => compare_int(&v1.cloned(), &v2.cloned(), &field_type),
+                (ScalarValueRef::Int(v1), ScalarValueRef::Int(v2)) => compare_int(&v1.cloned(), &v2.cloned(), field_type),
                 (ScalarValueRef::Bytes(None), ScalarValueRef::Bytes(None)) => Ordering::Equal,
                 (ScalarValueRef::Bytes(Some(_)), ScalarValueRef::Bytes(None)) => Ordering::Greater,
                 (ScalarValueRef::Bytes(None), ScalarValueRef::Bytes(Some(_))) => Ordering::Less,
diff --git a/components/tidb_query_datatype/src/codec/data_type/vector.rs b/components/tidb_query_datatype/src/codec/data_type/vector.rs
index c23ea40ded5..21b5c01b085 100644
--- a/components/tidb_query_datatype/src/codec/data_type/vector.rs
+++ b/components/tidb_query_datatype/src/codec/data_type/vector.rs
@@ -331,8 +331,8 @@ impl VectorValue {
                     None => {
                         output.write_evaluable_datum_null()?;
                     }
-                    Some(ref val) => {
-                        output.write_evaluable_datum_bytes(*val)?;
+                    Some(val) => {
+                        output.write_evaluable_datum_bytes(val)?;
                     }
                 }
                 Ok(())
@@ -403,7 +403,7 @@ impl VectorValue {
                     None => {
                         output.write_evaluable_datum_null()?;
                     }
-                    Some(ref val) => {
+                    Some(val) => {
                         let sort_key = match_template_collator! {
                             TT, match field_type.collation()? {
                                 Collation::TT => TT::sort_key(val)?
diff --git a/components/tidb_query_datatype/src/codec/mysql/decimal.rs b/components/tidb_query_datatype/src/codec/mysql/decimal.rs
index 047a2eeb592..e8874fe439f 100644
--- a/components/tidb_query_datatype/src/codec/mysql/decimal.rs
+++ b/components/tidb_query_datatype/src/codec/mysql/decimal.rs
@@ -2397,7 +2397,7 @@ mod tests {
     use std::cmp::Ordering;
     use std::collections::hash_map::DefaultHasher;
     use std::f64::EPSILON;
-    use std::iter::repeat;
+
     use std::sync::Arc;
 
     #[test]
@@ -3199,9 +3199,9 @@ mod tests {
 
     #[test]
     fn test_add() {
-        let a = "2".to_owned() + &repeat('1').take(71).collect::<String>();
-        let b: String = repeat('8').take(81).collect();
-        let c = "8888888890".to_owned() + &repeat('9').take(71).collect::<String>();
+        let a = "2".to_owned() + &"1".repeat(71);
+        let b: String = "8".repeat(81);
+        let c = "8888888890".to_owned() + &"9".repeat(71);
         let cases = vec![
             (
                 ".00012345000098765",
@@ -3294,8 +3294,8 @@ mod tests {
 
     #[test]
     fn test_mul() {
-        let a = "1".to_owned() + &repeat('0').take(60).collect::<String>();
-        let b = "1".to_owned() + &repeat("0").take(60).collect::<String>();
+        let a = "1".to_owned() + &"0".repeat(60);
+        let b = "1".to_owned() + &"0".repeat(60);
         let cases = vec![
             ("12", "10", Res::Ok("120")),
             ("0", "-1.1", Res::Ok("0")),
diff --git a/components/tidb_query_datatype/src/codec/mysql/enums.rs b/components/tidb_query_datatype/src/codec/mysql/enums.rs
index 6f9cf48d44e..02689b5c9d9 100644
--- a/components/tidb_query_datatype/src/codec/mysql/enums.rs
+++ b/components/tidb_query_datatype/src/codec/mysql/enums.rs
@@ -162,7 +162,7 @@ impl<'a> PartialEq for EnumRef<'a> {
 
 impl<'a> Ord for EnumRef<'a> {
     fn cmp(&self, other: &Self) -> Ordering {
-        self.value.cmp(&other.value)
+        self.value.cmp(other.value)
     }
 }
 
diff --git a/components/tidb_query_datatype/src/codec/mysql/json/jcodec.rs b/components/tidb_query_datatype/src/codec/mysql/json/jcodec.rs
index ad89dd937d8..db5efd6b922 100644
--- a/components/tidb_query_datatype/src/codec/mysql/json/jcodec.rs
+++ b/components/tidb_query_datatype/src/codec/mysql/json/jcodec.rs
@@ -241,7 +241,7 @@ pub trait JsonDecoder: NumberDecoder {
             }
             JsonType::String => {
                 let value = self.bytes();
-                let (str_len, len_len) = NumberCodec::try_decode_var_u64(&value)?;
+                let (str_len, len_len) = NumberCodec::try_decode_var_u64(value)?;
                 self.read_bytes(str_len as usize + len_len)?
             }
             JsonType::I64 | JsonType::U64 | JsonType::Double => self.read_bytes(NUMBER_LEN)?,
diff --git a/components/tidb_query_datatype/src/codec/mysql/json/json_depth.rs b/components/tidb_query_datatype/src/codec/mysql/json/json_depth.rs
index 3ae6e041466..92683ed335c 100644
--- a/components/tidb_query_datatype/src/codec/mysql/json/json_depth.rs
+++ b/components/tidb_query_datatype/src/codec/mysql/json/json_depth.rs
@@ -6,7 +6,7 @@ use super::{JsonRef, JsonType};
 impl<'a> JsonRef<'a> {
     /// Returns maximum depth of JSON document
     pub fn depth(&self) -> Result<i64> {
-        depth_json(&self)
+        depth_json(self)
     }
 }
 
diff --git a/components/tidb_query_datatype/src/codec/mysql/json/json_keys.rs b/components/tidb_query_datatype/src/codec/mysql/json/json_keys.rs
index 25190b59937..2f03353b0f0 100644
--- a/components/tidb_query_datatype/src/codec/mysql/json/json_keys.rs
+++ b/components/tidb_query_datatype/src/codec/mysql/json/json_keys.rs
@@ -30,7 +30,7 @@ impl<'a> JsonRef<'a> {
                 None => Ok(None),
             }
         } else {
-            json_keys(&self)
+            json_keys(self)
         }
     }
 }
diff --git a/components/tidb_query_datatype/src/codec/mysql/json/json_modify.rs b/components/tidb_query_datatype/src/codec/mysql/json/json_modify.rs
index a7d5d35819e..159ca66530f 100644
--- a/components/tidb_query_datatype/src/codec/mysql/json/json_modify.rs
+++ b/components/tidb_query_datatype/src/codec/mysql/json/json_modify.rs
@@ -47,9 +47,9 @@ impl<'a> JsonRef<'a> {
         for (expr, value) in path_expr_list.iter().zip(values.into_iter()) {
             let modifier = BinaryModifier::new(res.as_ref());
             res = match mt {
-                ModifyType::Insert => modifier.insert(&expr, value)?,
-                ModifyType::Replace => modifier.replace(&expr, value)?,
-                ModifyType::Set => modifier.set(&expr, value)?,
+                ModifyType::Insert => modifier.insert(expr, value)?,
+                ModifyType::Replace => modifier.replace(expr, value)?,
+                ModifyType::Set => modifier.set(expr, value)?,
             };
         }
         Ok(res)
diff --git a/components/tidb_query_datatype/src/codec/mysql/json/mod.rs b/components/tidb_query_datatype/src/codec/mysql/json/mod.rs
index e79d4b2d89f..760d6413590 100644
--- a/components/tidb_query_datatype/src/codec/mysql/json/mod.rs
+++ b/components/tidb_query_datatype/src/codec/mysql/json/mod.rs
@@ -145,7 +145,7 @@ impl<'a> JsonRef<'a> {
 
     /// Returns the underlying value slice
     pub fn value(&self) -> &'a [u8] {
-        &self.value
+        self.value
     }
 
     // Returns the JSON value as u64
diff --git a/components/tidb_query_datatype/src/codec/row/v2/compat_v1.rs b/components/tidb_query_datatype/src/codec/row/v2/compat_v1.rs
index 5c1b246cfad..d601c2d4cb6 100644
--- a/components/tidb_query_datatype/src/codec/row/v2/compat_v1.rs
+++ b/components/tidb_query_datatype/src/codec/row/v2/compat_v1.rs
@@ -145,7 +145,7 @@ mod tests {
 
     fn encode_to_v1_compatible(mut ctx: &mut EvalContext, col: &Column) -> Vec<u8> {
         let mut buf_v2 = vec![];
-        buf_v2.write_value(&mut ctx, &col).unwrap();
+        buf_v2.write_value(&mut ctx, col).unwrap();
         let mut buf_v1 = vec![];
         buf_v1.write_v2_as_datum(&buf_v2, col.ft()).unwrap();
         buf_v1
diff --git a/components/tidb_query_datatype/src/codec/table.rs b/components/tidb_query_datatype/src/codec/table.rs
index f7c899b68c8..adf2f60b6af 100644
--- a/components/tidb_query_datatype/src/codec/table.rs
+++ b/components/tidb_query_datatype/src/codec/table.rs
@@ -814,16 +814,16 @@ mod tests {
     #[test]
     fn test_check_key_type() {
         let record_key = encode_row_key(TABLE_ID, 1);
-        assert!(check_key_type(&record_key.as_slice(), RECORD_PREFIX_SEP).is_ok());
-        assert!(check_key_type(&record_key.as_slice(), INDEX_PREFIX_SEP).is_err());
+        assert!(check_key_type(record_key.as_slice(), RECORD_PREFIX_SEP).is_ok());
+        assert!(check_key_type(record_key.as_slice(), INDEX_PREFIX_SEP).is_err());
 
         let (_, index_key) =
             generate_index_data_for_test(TABLE_ID, INDEX_ID, 1, &Datum::I64(1), true);
-        assert!(check_key_type(&index_key.as_slice(), RECORD_PREFIX_SEP).is_err());
-        assert!(check_key_type(&index_key.as_slice(), INDEX_PREFIX_SEP).is_ok());
+        assert!(check_key_type(index_key.as_slice(), RECORD_PREFIX_SEP).is_err());
+        assert!(check_key_type(index_key.as_slice(), INDEX_PREFIX_SEP).is_ok());
 
         let too_small_key = vec![0];
-        assert!(check_key_type(&too_small_key.as_slice(), RECORD_PREFIX_SEP).is_err());
-        assert!(check_key_type(&too_small_key.as_slice(), INDEX_PREFIX_SEP).is_err());
+        assert!(check_key_type(too_small_key.as_slice(), RECORD_PREFIX_SEP).is_err());
+        assert!(check_key_type(too_small_key.as_slice(), INDEX_PREFIX_SEP).is_err());
     }
 }
diff --git a/components/tidb_query_executors/src/index_scan_executor.rs b/components/tidb_query_executors/src/index_scan_executor.rs
index 3614410a1ce..45759d03eba 100644
--- a/components/tidb_query_executors/src/index_scan_executor.rs
+++ b/components/tidb_query_executors/src/index_scan_executor.rs
@@ -94,7 +94,7 @@ impl<S: Storage> BatchIndexScanExecutor<S> {
 
         let schema: Vec<_> = columns_info
             .iter()
-            .map(|ci| field_type_from_column_info(&ci))
+            .map(|ci| field_type_from_column_info(ci))
             .collect();
 
         let columns_id_without_handle: Vec<_> = columns_info
diff --git a/components/tidb_query_executors/src/lib.rs b/components/tidb_query_executors/src/lib.rs
index 68f04c7bbb6..1ca2a7e2771 100644
--- a/components/tidb_query_executors/src/lib.rs
+++ b/components/tidb_query_executors/src/lib.rs
@@ -10,8 +10,8 @@
 #![allow(incomplete_features)]
 #![feature(proc_macro_hygiene)]
 #![feature(specialization)]
-#![feature(const_fn)]
 #![feature(const_fn_fn_ptr_basics)]
+#![feature(const_fn_trait_bound)]
 #![feature(const_mut_refs)]
 
 #[macro_use(box_try, warn)]
diff --git a/components/tidb_query_executors/src/runner.rs b/components/tidb_query_executors/src/runner.rs
index bdda997ba99..7e962afa68e 100644
--- a/components/tidb_query_executors/src/runner.rs
+++ b/components/tidb_query_executors/src/runner.rs
@@ -77,30 +77,30 @@ impl BatchExecutorsRunner<()> {
             match ed.get_tp() {
                 ExecType::TypeTableScan => {
                     let descriptor = ed.get_tbl_scan();
-                    BatchTableScanExecutor::check_supported(&descriptor)
+                    BatchTableScanExecutor::check_supported(descriptor)
                         .map_err(|e| other_err!("BatchTableScanExecutor: {}", e))?;
                 }
                 ExecType::TypeIndexScan => {
                     let descriptor = ed.get_idx_scan();
-                    BatchIndexScanExecutor::check_supported(&descriptor)
+                    BatchIndexScanExecutor::check_supported(descriptor)
                         .map_err(|e| other_err!("BatchIndexScanExecutor: {}", e))?;
                 }
                 ExecType::TypeSelection => {
                     let descriptor = ed.get_selection();
-                    BatchSelectionExecutor::check_supported(&descriptor)
+                    BatchSelectionExecutor::check_supported(descriptor)
                         .map_err(|e| other_err!("BatchSelectionExecutor: {}", e))?;
                 }
                 ExecType::TypeAggregation | ExecType::TypeStreamAgg
                     if ed.get_aggregation().get_group_by().is_empty() =>
                 {
                     let descriptor = ed.get_aggregation();
-                    BatchSimpleAggregationExecutor::check_supported(&descriptor)
+                    BatchSimpleAggregationExecutor::check_supported(descriptor)
                         .map_err(|e| other_err!("BatchSimpleAggregationExecutor: {}", e))?;
                 }
                 ExecType::TypeAggregation => {
                     let descriptor = ed.get_aggregation();
-                    if BatchFastHashAggregationExecutor::check_supported(&descriptor).is_err() {
-                        BatchSlowHashAggregationExecutor::check_supported(&descriptor)
+                    if BatchFastHashAggregationExecutor::check_supported(descriptor).is_err() {
+                        BatchSlowHashAggregationExecutor::check_supported(descriptor)
                             .map_err(|e| other_err!("BatchSlowHashAggregationExecutor: {}", e))?;
                     }
                 }
@@ -108,13 +108,13 @@ impl BatchExecutorsRunner<()> {
                     // Note: We won't check whether the source of stream aggregation is in order.
                     //       It is undefined behavior if the source is unordered.
                     let descriptor = ed.get_aggregation();
-                    BatchStreamAggregationExecutor::check_supported(&descriptor)
+                    BatchStreamAggregationExecutor::check_supported(descriptor)
                         .map_err(|e| other_err!("BatchStreamAggregationExecutor: {}", e))?;
                 }
                 ExecType::TypeLimit => {}
                 ExecType::TypeTopN => {
                     let descriptor = ed.get_top_n();
-                    BatchTopNExecutor::check_supported(&descriptor)
+                    BatchTopNExecutor::check_supported(descriptor)
                         .map_err(|e| other_err!("BatchTopNExecutor: {}", e))?;
                 }
                 ExecType::TypeJoin => {
@@ -247,8 +247,7 @@ pub fn build_executors<S: Storage + 'static>(
                 )
             }
             ExecType::TypeAggregation => {
-                if BatchFastHashAggregationExecutor::check_supported(&ed.get_aggregation()).is_ok()
-                {
+                if BatchFastHashAggregationExecutor::check_supported(ed.get_aggregation()).is_ok() {
                     EXECUTOR_COUNT_METRICS.batch_fast_hash_aggr.inc();
 
                     Box::new(
diff --git a/components/tidb_query_executors/src/table_scan_executor.rs b/components/tidb_query_executors/src/table_scan_executor.rs
index d4a78a470f4..4cef26ac9a4 100644
--- a/components/tidb_query_executors/src/table_scan_executor.rs
+++ b/components/tidb_query_executors/src/table_scan_executor.rs
@@ -202,8 +202,8 @@ impl TableScanExecutorImpl {
                     // but will output a log anyway.
                     warn!(
                         "Ignored duplicated row datum in table scan";
-                        "key" => log_wrappers::Value::key(&key),
-                        "value" => log_wrappers::Value::value(&value),
+                        "key" => log_wrappers::Value::key(key),
+                        "value" => log_wrappers::Value::value(value),
                         "dup_column_id" => column_id,
                     );
                 }
diff --git a/components/tidb_query_expr/src/impl_cast.rs b/components/tidb_query_expr/src/impl_cast.rs
index 67686b0e884..23dd20c48f2 100644
--- a/components/tidb_query_expr/src/impl_cast.rs
+++ b/components/tidb_query_expr/src/impl_cast.rs
@@ -6102,7 +6102,7 @@ mod tests {
                                 } else {
                                     max_val_str = "838:59:59";
                                 }
-                                let max_expect = Duration::parse(&mut ctx, &max_val_str, fsp);
+                                let max_expect = Duration::parse(&mut ctx, max_val_str, fsp);
                                 let log = format!(
                                     "func_name: {}, input: {}, output: {:?}, output_warn: {:?}, expect: {:?}",
                                     func_name,
diff --git a/components/tidb_query_expr/src/impl_compare.rs b/components/tidb_query_expr/src/impl_compare.rs
index c6d0e5e05ed..babe4819a22 100644
--- a/components/tidb_query_expr/src/impl_compare.rs
+++ b/components/tidb_query_expr/src/impl_compare.rs
@@ -106,7 +106,7 @@ impl<F: CmpOp> Comparer for UintIntComparer<F> {
                 let ordering = if *rhs < 0 || *lhs as u64 > std::i64::MAX as u64 {
                     Ordering::Greater
                 } else {
-                    lhs.cmp(&rhs)
+                    lhs.cmp(rhs)
                 };
                 Some(F::compare_order(ordering) as i64)
             }
@@ -130,7 +130,7 @@ impl<F: CmpOp> Comparer for IntUintComparer<F> {
                 let ordering = if *lhs < 0 || *rhs as u64 > std::i64::MAX as u64 {
                     Ordering::Less
                 } else {
-                    lhs.cmp(&rhs)
+                    lhs.cmp(rhs)
                 };
                 Some(F::compare_order(ordering) as i64)
             }
@@ -353,7 +353,7 @@ pub fn greatest_time(ctx: &mut EvalContext, args: &[Option<BytesRef>]) -> Result
                             .map(|_| Ok(None))?;
                     }
                 };
-                match Time::parse_datetime(ctx, &s, Time::parse_fsp(&s), true) {
+                match Time::parse_datetime(ctx, s, Time::parse_fsp(s), true) {
                     Ok(t) => greatest = max(greatest, Some(t)),
                     Err(_) => {
                         return ctx
@@ -392,7 +392,7 @@ pub fn least_time(mut ctx: &mut EvalContext, args: &[Option<BytesRef>]) -> Resul
                             .map(|_| Ok(None))?;
                     }
                 };
-                match Time::parse_datetime(ctx, &s, Time::parse_fsp(&s), true) {
+                match Time::parse_datetime(ctx, s, Time::parse_fsp(s), true) {
                     Ok(t) => least = min(least, Some(t)),
                     Err(_) => {
                         return ctx
diff --git a/components/tidb_query_expr/src/impl_compare_in.rs b/components/tidb_query_expr/src/impl_compare_in.rs
index af498f7b6dd..ab6845711b3 100644
--- a/components/tidb_query_expr/src/impl_compare_in.rs
+++ b/components/tidb_query_expr/src/impl_compare_in.rs
@@ -821,7 +821,7 @@ mod tests {
                 black_box(&mut ctx),
                 black_box(schema),
                 black_box(&mut columns),
-                black_box(&logical_rows),
+                black_box(logical_rows),
                 black_box(1024),
             );
             assert!(result.is_ok());
diff --git a/components/tidb_query_expr/src/impl_json.rs b/components/tidb_query_expr/src/impl_json.rs
index 9da5cfceea7..ac5eb9539ad 100644
--- a/components/tidb_query_expr/src/impl_json.rs
+++ b/components/tidb_query_expr/src/impl_json.rs
@@ -211,7 +211,7 @@ fn json_unquote(arg: BytesRef) -> Result<Option<Bytes>> {
     let first_char = tmp_str.chars().next();
     let last_char = tmp_str.chars().last();
     if tmp_str.len() >= 2 && first_char == Some('"') && last_char == Some('"') {
-        let _: IgnoredAny = serde_json::from_str(&tmp_str)?;
+        let _: IgnoredAny = serde_json::from_str(tmp_str)?;
     }
     Ok(Some(Bytes::from(self::unquote_string(tmp_str)?)))
 }
@@ -227,7 +227,7 @@ fn valid_paths(expr: &tipb::Expr) -> Result<()> {
     let children = expr.get_children();
     super::function::validate_expr_return_type(&children[0], EvalType::Json)?;
     for child in children.iter().skip(1) {
-        super::function::validate_expr_return_type(&child, EvalType::Bytes)?;
+        super::function::validate_expr_return_type(child, EvalType::Bytes)?;
     }
     Ok(())
 }
@@ -319,10 +319,10 @@ fn parse_json_path_list(args: &[ScalarValueRef]) -> Result<Option<Vec<PathExpres
 fn parse_json_path(path: Option<BytesRef>) -> Result<Option<PathExpression>> {
     let json_path = match path {
         None => return Ok(None),
-        Some(p) => std::str::from_utf8(&p).map_err(tidb_query_datatype::codec::Error::from),
+        Some(p) => std::str::from_utf8(p).map_err(tidb_query_datatype::codec::Error::from),
     }?;
 
-    Ok(Some(parse_json_path_expr(&json_path)?))
+    Ok(Some(parse_json_path_expr(json_path)?))
 }
 
 #[cfg(test)]
@@ -549,13 +549,11 @@ mod tests {
         ];
 
         for (vargs, expected) in cases {
-            let vargs = vargs
+            let mut new_vargs: Vec<ScalarValue> = vec![];
+            for (key, value) in vargs
                 .into_iter()
                 .map(|(key, value)| (Bytes::from(key), value.map(|s| Json::from_str(s).unwrap())))
-                .collect::<Vec<_>>();
-
-            let mut new_vargs: Vec<ScalarValue> = vec![];
-            for (key, value) in vargs.into_iter() {
+            {
                 new_vargs.push(ScalarValue::from(key));
                 new_vargs.push(ScalarValue::from(value));
             }
diff --git a/components/tidb_query_expr/src/impl_math.rs b/components/tidb_query_expr/src/impl_math.rs
index 96275667e74..4cddd5a4a37 100644
--- a/components/tidb_query_expr/src/impl_math.rs
+++ b/components/tidb_query_expr/src/impl_math.rs
@@ -24,7 +24,7 @@ pub fn pi() -> Result<Option<Real>> {
 #[rpn_fn]
 #[inline]
 pub fn crc32(arg: BytesRef) -> Result<Option<Int>> {
-    Ok(Some(i64::from(file_system::calc_crc32_bytes(&arg))))
+    Ok(Some(i64::from(file_system::calc_crc32_bytes(arg))))
 }
 
 #[inline]
diff --git a/components/tidb_query_expr/src/impl_string.rs b/components/tidb_query_expr/src/impl_string.rs
index d985ef9ec7f..a75fe056d81 100644
--- a/components/tidb_query_expr/src/impl_string.rs
+++ b/components/tidb_query_expr/src/impl_string.rs
@@ -117,7 +117,7 @@ pub fn locate_2_args_utf8<C: Collator>(substr: BytesRef, s: BytesRef) -> Result<
     let offset = if C::IS_CASE_INSENSITIVE {
         find_str(&s.to_lowercase(), &substr.to_lowercase())
     } else {
-        find_str(&s, &substr)
+        find_str(s, substr)
     };
     Ok(Some(offset.map_or(0, |i| 1 + i as i64)))
 }
@@ -146,7 +146,7 @@ pub fn locate_3_args_utf8<C: Collator>(
     let offset = if C::IS_CASE_INSENSITIVE {
         find_str(&s[start..].to_lowercase(), &substr.to_lowercase())
     } else {
-        find_str(&s[start..], &substr)
+        find_str(&s[start..], substr)
     };
     Ok(Some(offset.map_or(0, |i| pos + i as i64)))
 }
@@ -260,14 +260,14 @@ pub fn lpad(arg: BytesRef, len: &Int, pad: BytesRef, writer: BytesWriter) -> Res
             // Write full pads
             let num_pads = (target_len - arg.len()) / pad.len();
             for _ in 0..num_pads {
-                writer.partial_write(&pad);
+                writer.partial_write(pad);
             }
 
             // Write last incomplete pad (might be none)
             let last_pad_len = (target_len - arg.len()) % pad.len();
             writer.partial_write(&pad[..last_pad_len]);
 
-            writer.partial_write(&arg);
+            writer.partial_write(arg);
             Ok(writer.finish())
         }
     }
@@ -323,12 +323,12 @@ pub fn rpad(arg: BytesRef, len: &Int, pad: BytesRef, writer: BytesWriter) -> Res
         }
         Some(target_len) => {
             let mut writer = writer.begin();
-            writer.partial_write(&arg);
+            writer.partial_write(arg);
 
             // Write full pads
             let num_pads = (target_len - arg.len()) / pad.len();
             for _ in 0..num_pads {
-                writer.partial_write(&pad);
+                writer.partial_write(pad);
             }
 
             // Write last incomplete pad (might be none)
@@ -497,7 +497,7 @@ pub fn insert(
     }
     let mut ret = Vec::with_capacity(newstr.len() + s.len());
     ret.extend_from_slice(&s[0..upos - 1]);
-    ret.extend_from_slice(&newstr);
+    ret.extend_from_slice(newstr);
     ret.extend_from_slice(&s[upos + ulen - 1..]);
     Ok(writer.write(Some(ret)))
 }
@@ -671,7 +671,7 @@ fn elt_validator(expr: &tipb::Expr) -> Result<()> {
     assert!(children.len() >= 2);
     super::function::validate_expr_return_type(&children[0], EvalType::Int)?;
     for child in children.iter().skip(1) {
-        super::function::validate_expr_return_type(&child, EvalType::Bytes)?;
+        super::function::validate_expr_return_type(child, EvalType::Bytes)?;
     }
     Ok(())
 }
@@ -711,7 +711,7 @@ pub fn substring_index(
     let mut remaining_pattern_count = count.abs();
     let mut bound = 0;
     while remaining_pattern_count > 0 {
-        if let Some(offset) = finder(&remaining, delim) {
+        if let Some(offset) = finder(remaining, delim) {
             if count > 0 {
                 bound += offset + delim.len();
                 remaining = &s[bound..];
@@ -750,7 +750,7 @@ pub fn strcmp<C: Collator>(left: BytesRef, right: BytesRef) -> Result<Option<i64
 #[rpn_fn]
 #[inline]
 pub fn instr(s: BytesRef, substr: BytesRef) -> Result<Option<Int>> {
-    Ok(twoway::find_bytes(&s, &substr)
+    Ok(twoway::find_bytes(s, substr)
         .map(|i| 1 + i as i64)
         .or(Some(0)))
 }
diff --git a/components/tidb_query_expr/src/impl_time.rs b/components/tidb_query_expr/src/impl_time.rs
index 01959305855..75b6437ac76 100644
--- a/components/tidb_query_expr/src/impl_time.rs
+++ b/components/tidb_query_expr/src/impl_time.rs
@@ -323,7 +323,7 @@ pub fn add_datetime_and_string(
     arg0: &DateTime,
     arg1: BytesRef,
 ) -> Result<Option<DateTime>> {
-    let arg1 = std::str::from_utf8(&arg1).map_err(Error::Encoding)?;
+    let arg1 = std::str::from_utf8(arg1).map_err(Error::Encoding)?;
     let arg1 = match Duration::parse(ctx, arg1, MAX_FSP) {
         Ok(arg) => arg,
         Err(_) => return Ok(None),
@@ -350,7 +350,7 @@ pub fn add_date_and_string(
     arg0: &DateTime,
     arg1: BytesRef,
 ) -> Result<Option<DateTime>> {
-    let arg1 = std::str::from_utf8(&arg1).map_err(Error::Encoding)?;
+    let arg1 = std::str::from_utf8(arg1).map_err(Error::Encoding)?;
     let arg1 = match Duration::parse(ctx, arg1, MAX_FSP) {
         Ok(arg) => arg,
         Err(_) => return Ok(None),
@@ -423,7 +423,7 @@ pub fn sub_datetime_and_string(
     datetime: &DateTime,
     duration_str: BytesRef,
 ) -> Result<Option<DateTime>> {
-    let duration_str = std::str::from_utf8(&duration_str).map_err(Error::Encoding)?;
+    let duration_str = std::str::from_utf8(duration_str).map_err(Error::Encoding)?;
     let duration = match Duration::parse(ctx, duration_str, MAX_FSP) {
         Ok(duration) => duration,
         Err(_) => return Ok(None),
@@ -450,7 +450,7 @@ pub fn sub_duration_and_string(
     arg1: &Duration,
     arg2: BytesRef,
 ) -> Result<Option<Duration>> {
-    let arg2 = std::str::from_utf8(&arg2).map_err(Error::Encoding)?;
+    let arg2 = std::str::from_utf8(arg2).map_err(Error::Encoding)?;
     let arg2 = match Duration::parse(ctx, arg2, MAX_FSP) {
         Ok(arg) => arg,
         Err(_) => return Ok(None),
@@ -741,7 +741,7 @@ pub fn add_duration_and_string(
     arg1: &Duration,
     arg2: BytesRef,
 ) -> Result<Option<Duration>> {
-    let arg2 = std::str::from_utf8(&arg2).map_err(Error::Encoding)?;
+    let arg2 = std::str::from_utf8(arg2).map_err(Error::Encoding)?;
     let arg2 = match Duration::parse(ctx, arg2, MAX_FSP) {
         Ok(arg) => arg,
         Err(_) => return Ok(None),
diff --git a/components/tidb_query_expr/src/lib.rs b/components/tidb_query_expr/src/lib.rs
index e4014a15c80..d861e48d001 100644
--- a/components/tidb_query_expr/src/lib.rs
+++ b/components/tidb_query_expr/src/lib.rs
@@ -10,10 +10,9 @@
 #![allow(incomplete_features)]
 #![feature(proc_macro_hygiene)]
 #![feature(specialization)]
-#![feature(const_fn)]
 #![feature(test)]
-#![feature(int_error_matching)]
 #![feature(const_fn_fn_ptr_basics)]
+#![feature(const_fn_trait_bound)]
 #![feature(const_mut_refs)]
 
 #[macro_use(box_err, box_try, try_opt)]
diff --git a/components/tidb_query_expr/src/types/expr_eval.rs b/components/tidb_query_expr/src/types/expr_eval.rs
index 38d2ad6458a..43b84730dd4 100644
--- a/components/tidb_query_expr/src/types/expr_eval.rs
+++ b/components/tidb_query_expr/src/types/expr_eval.rs
@@ -36,7 +36,7 @@ impl<'a> RpnStackNodeVectorValue<'a> {
     /// Gets a reference to the inner physical vector value.
     pub fn as_ref(&self) -> &VectorValue {
         match self {
-            RpnStackNodeVectorValue::Generated { physical_value, .. } => &physical_value,
+            RpnStackNodeVectorValue::Generated { physical_value, .. } => physical_value,
             RpnStackNodeVectorValue::Ref { physical_value, .. } => *physical_value,
         }
     }
@@ -99,7 +99,7 @@ impl<'a> RpnStackNode<'a> {
     pub fn vector_value(&self) -> Option<&RpnStackNodeVectorValue<'_>> {
         match self {
             RpnStackNode::Scalar { .. } => None,
-            RpnStackNode::Vector { value, .. } => Some(&value),
+            RpnStackNode::Vector { value, .. } => Some(value),
         }
     }
 
@@ -224,7 +224,7 @@ impl RpnExpression {
                     assert_eq!(input_logical_rows.len(), output_rows);
                     stack.push(RpnStackNode::Vector {
                         value: RpnStackNodeVectorValue::Ref {
-                            physical_value: &decoded_physical_column,
+                            physical_value: decoded_physical_column,
                             logical_rows: input_logical_rows,
                         },
                         field_type,
diff --git a/components/tikv_kv/src/btree_engine.rs b/components/tikv_kv/src/btree_engine.rs
index 07f748ec9dd..3b385c630ed 100644
--- a/components/tikv_kv/src/btree_engine.rs
+++ b/components/tikv_kv/src/btree_engine.rs
@@ -94,7 +94,7 @@ impl Engine for BTreeEngine {
         if batch.modifies.is_empty() {
             return Err(EngineError::from(EngineErrorInner::EmptyRequest));
         }
-        cb((CbContext::new(), write_modifies(&self, batch.modifies)));
+        cb((CbContext::new(), write_modifies(self, batch.modifies)));
 
         Ok(())
     }
@@ -105,7 +105,7 @@ impl Engine for BTreeEngine {
         _ctx: SnapContext<'_>,
         cb: EngineCallback<Self::Snap>,
     ) -> EngineResult<()> {
-        cb((CbContext::new(), Ok(BTreeEngineSnapshot::new(&self))));
+        cb((CbContext::new(), Ok(BTreeEngineSnapshot::new(self))));
         Ok(())
     }
 }
diff --git a/components/tikv_util/src/config.rs b/components/tikv_util/src/config.rs
index a48d4b83c4c..95b805c6e48 100644
--- a/components/tikv_util/src/config.rs
+++ b/components/tikv_util/src/config.rs
@@ -1255,7 +1255,7 @@ impl TomlWriter {
 
     pub fn write_change(&mut self, src: String, mut change: HashMap<String, String>) {
         for line in src.lines() {
-            match TomlLine::parse(&line) {
+            match TomlLine::parse(line) {
                 TomlLine::Table(keys) => {
                     self.write_current_table(&mut change);
                     self.write(line.as_bytes());
diff --git a/components/tikv_util/src/future.rs b/components/tikv_util/src/future.rs
index fae8f47bbfa..f9ee7712269 100644
--- a/components/tikv_util/src/future.rs
+++ b/components/tikv_util/src/future.rs
@@ -83,7 +83,7 @@ impl ArcWake for BatchCommandsWaker {
     fn wake_by_ref(arc_self: &Arc<Self>) {
         let mut future_slot = arc_self.0.lock().unwrap();
         if let Some(mut future) = future_slot.take() {
-            let waker = task::waker_ref(&arc_self);
+            let waker = task::waker_ref(arc_self);
             let cx = &mut Context::from_waker(&*waker);
             match future.as_mut().poll(cx) {
                 Poll::Pending => {
diff --git a/components/tikv_util/src/metrics/threads_linux.rs b/components/tikv_util/src/metrics/threads_linux.rs
index 12740a62174..f93dc07849b 100644
--- a/components/tikv_util/src/metrics/threads_linux.rs
+++ b/components/tikv_util/src/metrics/threads_linux.rs
@@ -314,7 +314,7 @@ fn collect_metrics_by_name(
     let mut new_map: HashMap<String, u64> = HashMap::default();
     for (tid, name) in names {
         let new_value = new_map.entry(name.to_string()).or_insert(0);
-        if let Some(value) = values.get(&tid) {
+        if let Some(value) = values.get(tid) {
             *new_value += *value as u64;
         }
     }
diff --git a/components/tikv_util/src/sys/cgroup.rs b/components/tikv_util/src/sys/cgroup.rs
index 59dc8436397..429e6d8c90f 100644
--- a/components/tikv_util/src/sys/cgroup.rs
+++ b/components/tikv_util/src/sys/cgroup.rs
@@ -188,7 +188,7 @@ mod tests {
             4:memory:/kubepods/burstable/poda2ebe2cd-64c7-11ea-8799-eeeeeeeeeeee/a026c487f1168b7f5442444ac8e35161dfcde87c175ef27d9a806270e267a575
             5:cpuacct,cpu:/kubepods/burstable/poda2ebe2cd-64c7-11ea-8799-eeeeeeeeeeee/a026c487f1168b7f5442444ac8e35161dfcde87c175ef27d9a806270e267a575
         "#;
-        let cgroups = parse_proc_cgroup_v1(&content);
+        let cgroups = parse_proc_cgroup_v1(content);
         assert_eq!(
             cgroups.get("memory").unwrap(),
             "/kubepods/burstable/poda2ebe2cd-64c7-11ea-8799-eeeeeeeeeeee/a026c487f1168b7f5442444ac8e35161dfcde87c175ef27d9a806270e267a575"
@@ -203,7 +203,7 @@ mod tests {
     #[test]
     fn test_parse_proc_cgroup_v2() {
         let content = "0::/test-all";
-        let cgroups = parse_proc_cgroup_v2(&content);
+        let cgroups = parse_proc_cgroup_v2(content);
         assert_eq!(cgroups.get("").unwrap(), "/test-all");
     }
 
diff --git a/fuzz/cli.rs b/fuzz/cli.rs
index cc49f6a32b7..26418b84031 100644
--- a/fuzz/cli.rs
+++ b/fuzz/cli.rs
@@ -121,7 +121,7 @@ fn write_fuzz_target_source_file(fuzzer: Fuzzer, target: &str) -> Result<()> {
             target_file_path.display()
         ))?;
 
-    let source = template.replace("__FUZZ_CLI_TARGET__", &target).replace(
+    let source = template.replace("__FUZZ_CLI_TARGET__", target).replace(
         "__FUZZ_GENERATE_COMMENT__",
         "NOTE: AUTO GENERATED FROM `template.rs`",
     );
@@ -318,7 +318,7 @@ fn run_libfuzzer(target: &str) -> Result<()> {
     asan_options.push_str(" detect_odr_violation=0");
 
     let fuzzer_bin = Command::new("cargo")
-        .args(&["run", "--target", &target_platform, "--bin", target, "--"])
+        .args(&["run", "--target", target_platform, "--bin", target, "--"])
         .arg(&corpus_dir)
         .arg(&seed_dir)
         .env("RUSTFLAGS", &rust_flags)
diff --git a/rust-toolchain b/rust-toolchain
index 414d33e9a55..08c09fbcd18 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2021-04-15
+nightly-2021-07-28
diff --git a/scripts/clippy b/scripts/clippy
index e80fda1d83a..d5b9f4f40fd 100755
--- a/scripts/clippy
+++ b/scripts/clippy
@@ -29,9 +29,12 @@ CLIPPY_LINTS=(-A clippy::module_inception  \
 	-A clippy::new_ret_no_self \
 	-A clippy::unnecessary_sort_by \
 	-A clippy::unnecessary_wraps \
+	-A clippy::bool_assert_comparison \
+	-A clippy::self_named_constructor \
+	-A clippy::enum_variant_names \
         -W clippy::dbg_macro \
         -W clippy::todo)
 
-cargo clippy --workspace --no-default-features \
+cargo clippy --workspace --fix --allow-staged --no-default-features \
 	--exclude fuzz-targets --exclude fuzzer-honggfuzz --exclude fuzzer-afl --exclude fuzzer-libfuzzer \
 	--features "${TIKV_ENABLE_FEATURES}" "$@" -- "${CLIPPY_LINTS[@]}"
diff --git a/src/config.rs b/src/config.rs
index 0070dcfe9ff..dc34a7bfbfc 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1502,7 +1502,7 @@ impl ConfigManager for DBConfigManger {
                 let cf_name = &cf_name[..(cf_name.len() - 2)];
                 if let Some(v) = cf_change.remove("block_cache_size") {
                     // currently we can't modify block_cache_size via set_options_cf
-                    self.set_block_cache_size(&cf_name, v.into())?;
+                    self.set_block_cache_size(cf_name, v.into())?;
                 }
                 if let Some(ConfigValue::Module(titan_change)) = cf_change.remove("titan") {
                     for (name, value) in titan_change {
@@ -1512,7 +1512,7 @@ impl ConfigManager for DBConfigManger {
                 if !cf_change.is_empty() {
                     let cf_change = config_value_to_string(cf_change.into_iter().collect());
                     let cf_change_slice = config_to_slice(&cf_change);
-                    self.set_cf_config(&cf_name, &cf_change_slice)?;
+                    self.set_cf_config(cf_name, &cf_change_slice)?;
                 }
             }
         }
@@ -2982,8 +2982,12 @@ fn to_config_change(change: HashMap<String, String>) -> CfgResult<ConfigChange>
     }
     let mut res = HashMap::new();
     for (name, value) in change {
-        let fields: Vec<_> = name.as_str().split('.').collect();
-        let fields: Vec<_> = fields.into_iter().map(|s| s.to_owned()).rev().collect();
+        let fields: Vec<_> = name
+            .as_str()
+            .split('.')
+            .map(|s| s.to_owned())
+            .rev()
+            .collect();
         helper(fields, &mut res, &TIKVCONFIG_TYPED, value)?;
     }
     Ok(res)
@@ -3045,8 +3049,12 @@ fn to_toml_encode(change: HashMap<String, String>) -> CfgResult<HashMap<String,
     }
     let mut dst = HashMap::new();
     for (name, value) in change {
-        let fields: Vec<_> = name.as_str().split('.').collect();
-        let fields: Vec<_> = fields.into_iter().map(|s| s.to_owned()).rev().collect();
+        let fields: Vec<_> = name
+            .as_str()
+            .split('.')
+            .map(|s| s.to_owned())
+            .rev()
+            .collect();
         if helper(fields, &TIKVCONFIG_TYPED)? {
             dst.insert(name.replace("_", "-"), format!("\"{}\"", value));
         } else {
diff --git a/src/coprocessor_v2/endpoint.rs b/src/coprocessor_v2/endpoint.rs
index f3ea659412f..d126e24f386 100644
--- a/src/coprocessor_v2/endpoint.rs
+++ b/src/coprocessor_v2/endpoint.rs
@@ -87,7 +87,7 @@ impl Endpoint {
             .map_err(|e| CoprocessorError::Other(format!("{}", e)))?;
         let plugin_version = plugin.version();
 
-        if !version_req.matches(&plugin_version) {
+        if !version_req.matches(plugin_version) {
             return Err(CoprocessorError::Other(format!(
                 "The plugin '{}' with version '{}' does not satisfy the version constraint '{}'",
                 plugin.name(),
diff --git a/src/import/duplicate_detect.rs b/src/import/duplicate_detect.rs
index 0b283d94efd..ab6366ccd2c 100644
--- a/src/import/duplicate_detect.rs
+++ b/src/import/duplicate_detect.rs
@@ -127,7 +127,7 @@ impl<S: Snapshot> DuplicateDetector<S> {
                         end_commit_ts,
                     )?);
                 }
-                duplicate_pairs.push(self.make_kv_pair(&current_key, write_value, commit_ts)?);
+                duplicate_pairs.push(self.make_kv_pair(current_key, write_value, commit_ts)?);
             }
             if commit_ts <= self.min_commit_ts {
                 self.skip_all_version(&start_key)?;
diff --git a/src/import/sst_service.rs b/src/import/sst_service.rs
index b2a941d0f2b..903daf8ebaa 100644
--- a/src/import/sst_service.rs
+++ b/src/import/sst_service.rs
@@ -196,7 +196,7 @@ where
             // must execute after geting a snapshot from raftstore to make sure that the
             // current leader has applied to current term.
             for sst in ssts.iter() {
-                if !importer.exist(&sst) {
+                if !importer.exist(sst) {
                     warn!(
                         "sst [{:?}] not exist. we may retry an operation that has already succeeded",
                         sst
diff --git a/src/lib.rs b/src/lib.rs
index dbffc28cd34..ce37df5a0dc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,12 +22,10 @@
 #![feature(cell_update)]
 #![feature(proc_macro_hygiene)]
 #![feature(min_specialization)]
-#![feature(const_fn)]
 #![feature(box_patterns)]
 #![feature(shrink_to)]
 #![feature(drain_filter)]
 #![feature(negative_impls)]
-#![feature(num_as_ne_bytes)]
 
 #[macro_use(fail_point)]
 extern crate fail;
diff --git a/src/server/debug.rs b/src/server/debug.rs
index 9f5e693f3eb..bd5987f73c5 100644
--- a/src/server/debug.rs
+++ b/src/server/debug.rs
@@ -491,7 +491,7 @@ impl<ER: RaftEngine> Debugger<ER> {
 
         let check_value = |value: &[u8]| -> Result<()> {
             let mut local_state = RegionLocalState::default();
-            box_try!(local_state.merge_from_bytes(&value));
+            box_try!(local_state.merge_from_bytes(value));
 
             match local_state.get_state() {
                 PeerState::Tombstone | PeerState::Applying => return Ok(()),
@@ -537,7 +537,7 @@ impl<ER: RaftEngine> Debugger<ER> {
 
         while box_try!(iter.valid()) {
             let (key, value) = (iter.key(), iter.value());
-            if let Ok((region_id, suffix)) = keys::decode_region_meta_key(&key) {
+            if let Ok((region_id, suffix)) = keys::decode_region_meta_key(key) {
                 if suffix != keys::REGION_STATE_SUFFIX {
                     box_try!(iter.next());
                     continue;
@@ -777,7 +777,7 @@ impl<ER: RaftEngine> Debugger<ER> {
 fn dump_mvcc_properties(db: &Arc<DB>, start: &[u8], end: &[u8]) -> Result<Vec<(String, String)>> {
     let mut num_entries = 0; // number of Rocksdb K/V entries.
 
-    let collection = box_try!(db.c().get_range_properties_cf(CF_WRITE, &start, &end));
+    let collection = box_try!(db.c().get_range_properties_cf(CF_WRITE, start, end));
     let num_files = collection.len();
 
     let mut mvcc_properties = MvccProperties::new();
@@ -831,7 +831,7 @@ fn recover_mvcc_for_range(
     read_only: bool,
     thread_index: usize,
 ) -> Result<()> {
-    let mut mvcc_checker = box_try!(MvccChecker::new(Arc::clone(&db), start_key, end_key));
+    let mut mvcc_checker = box_try!(MvccChecker::new(Arc::clone(db), start_key, end_key));
     mvcc_checker.thread_index = thread_index;
 
     let wb_limit: usize = 10240;
diff --git a/src/server/gc_worker/compaction_filter.rs b/src/server/gc_worker/compaction_filter.rs
index cf672b3094b..ee8604fb359 100644
--- a/src/server/gc_worker/compaction_filter.rs
+++ b/src/server/gc_worker/compaction_filter.rs
@@ -536,7 +536,7 @@ impl Drop for WriteCompactionFilter {
 
         #[cfg(any(test, feature = "failpoints"))]
         for callback in &self.callbacks_on_drop {
-            callback(&self);
+            callback(self);
         }
     }
 }
diff --git a/src/server/gc_worker/gc_worker.rs b/src/server/gc_worker/gc_worker.rs
index bc3d79851d0..b1303cd19ac 100644
--- a/src/server/gc_worker/gc_worker.rs
+++ b/src/server/gc_worker/gc_worker.rs
@@ -142,8 +142,8 @@ where
                 ..
             } => f
                 .debug_struct("Gc")
-                .field("start_key", &log_wrappers::Value::key(&start_key))
-                .field("end_key", &log_wrappers::Value::key(&end_key))
+                .field("start_key", &log_wrappers::Value::key(start_key))
+                .field("end_key", &log_wrappers::Value::key(end_key))
                 .field("safe_point", safe_point)
                 .finish(),
             GcTask::GcKeys { .. } => f.debug_struct("GcKeys").finish(),
@@ -220,7 +220,7 @@ where
     fn need_gc(&self, start_key: &[u8], end_key: &[u8], safe_point: TimeStamp) -> bool {
         let props = match self
             .engine
-            .get_mvcc_properties_cf(CF_WRITE, safe_point, &start_key, &end_key)
+            .get_mvcc_properties_cf(CF_WRITE, safe_point, start_key, end_key)
         {
             Some(c) => c,
             None => return true,
@@ -353,7 +353,7 @@ where
         let mut gc_info = GcInfo::default();
         let mut next_gc_key = keys.next();
         while let Some(ref key) = next_gc_key {
-            if let Err(e) = self.gc_key(safe_point, &key, &mut gc_info, &mut txn, &mut reader) {
+            if let Err(e) = self.gc_key(safe_point, key, &mut gc_info, &mut txn, &mut reader) {
                 error!(?e; "GC meets failure"; "key" => %key,);
                 // Switch to the next key if meets failure.
                 gc_info.is_completed = true;
diff --git a/src/server/gc_worker/mod.rs b/src/server/gc_worker/mod.rs
index f814851b473..3410282fd82 100644
--- a/src/server/gc_worker/mod.rs
+++ b/src/server/gc_worker/mod.rs
@@ -72,7 +72,7 @@ mod tests {
             .c()
             .get_mvcc_properties_cf(CF_WRITE, safe_point, &start, &end);
         if let Some(props) = props.as_ref() {
-            assert_eq!(check_need_gc(safe_point, 1.0, &props), need_gc);
+            assert_eq!(check_need_gc(safe_point, 1.0, props), need_gc);
         }
         props
     }
@@ -91,7 +91,7 @@ mod tests {
 
     fn test_without_properties(path: &str, region: &Region) {
         let db = open_db(path, false);
-        let mut engine = RegionEngine::new(&db, &region);
+        let mut engine = RegionEngine::new(&db, region);
 
         // Put 2 keys.
         engine.put(&[1], 1, 1);
@@ -109,7 +109,7 @@ mod tests {
 
     fn test_with_properties(path: &str, region: &Region) {
         let db = open_db(path, true);
-        let mut engine = RegionEngine::new(&db, &region);
+        let mut engine = RegionEngine::new(&db, region);
 
         // Put 2 keys.
         engine.put(&[2], 3, 3);
diff --git a/src/server/node.rs b/src/server/node.rs
index 2689ce79abe..c48c277e1ec 100644
--- a/src/server/node.rs
+++ b/src/server/node.rs
@@ -286,7 +286,7 @@ where
         );
 
         let region = initial_region(store_id, region_id, peer_id);
-        store::prepare_bootstrap_cluster(&engines, &region)?;
+        store::prepare_bootstrap_cluster(engines, &region)?;
         Ok(region)
     }
 
@@ -321,16 +321,16 @@ where
                     fail_point!("node_after_bootstrap_cluster", |_| Err(box_err!(
                         "injected error: node_after_bootstrap_cluster"
                     )));
-                    store::clear_prepare_bootstrap_key(&engines)?;
+                    store::clear_prepare_bootstrap_key(engines)?;
                     return Ok(());
                 }
                 Err(PdError::ClusterBootstrapped(_)) => match self.pd_client.get_region(b"") {
                     Ok(region) => {
                         if region == first_region {
-                            store::clear_prepare_bootstrap_key(&engines)?;
+                            store::clear_prepare_bootstrap_key(engines)?;
                         } else {
                             info!("cluster is already bootstrapped"; "cluster_id" => self.cluster_id);
-                            store::clear_prepare_bootstrap_cluster(&engines, region_id)?;
+                            store::clear_prepare_bootstrap_cluster(engines, region_id)?;
                         }
                         return Ok(());
                     }
diff --git a/src/server/raft_client.rs b/src/server/raft_client.rs
index f01251c30ac..e8c78dc918d 100644
--- a/src/server/raft_client.rs
+++ b/src/server/raft_client.rs
@@ -849,7 +849,7 @@ where
             if self.last_hash.0 == 0 || msg.region_id != self.last_hash.0 {
                 self.last_hash = (
                     msg.region_id,
-                    seahash::hash(msg.region_id.as_ne_bytes())
+                    seahash::hash(&msg.region_id.to_ne_bytes())
                         % self.builder.cfg.grpc_raft_conn_num as u64,
                 );
             };
diff --git a/src/server/ttl/ttl_checker.rs b/src/server/ttl/ttl_checker.rs
index 8043794e628..5a97b361e5d 100644
--- a/src/server/ttl/ttl_checker.rs
+++ b/src/server/ttl/ttl_checker.rs
@@ -154,8 +154,8 @@ pub fn check_ttl_and_compact_files<E: KvEngine>(
         Err(e) => {
             error!(
                 "get range ttl properties failed";
-                "range_start" => log_wrappers::Value::key(&start_key),
-                "range_end" => log_wrappers::Value::key(&end_key),
+                "range_start" => log_wrappers::Value::key(start_key),
+                "range_end" => log_wrappers::Value::key(end_key),
                 "err" => %e,
             );
             TTL_CHECKER_ACTIONS_COUNTER_VEC
@@ -189,8 +189,8 @@ pub fn check_ttl_and_compact_files<E: KvEngine>(
         if let Err(e) = engine.compact_files_cf(CF_DEFAULT, vec![file], None, 0, exclude_l0) {
             error!(
                 "execute ttl compact files failed";
-                "range_start" => log_wrappers::Value::key(&start_key),
-                "range_end" => log_wrappers::Value::key(&end_key),
+                "range_start" => log_wrappers::Value::key(start_key),
+                "range_end" => log_wrappers::Value::key(end_key),
                 "err" => %e,
             );
             TTL_CHECKER_ACTIONS_COUNTER_VEC
diff --git a/src/server/ttl/ttl_compaction_filter.rs b/src/server/ttl/ttl_compaction_filter.rs
index 0703ea631ae..9d1e9dccc94 100644
--- a/src/server/ttl/ttl_compaction_filter.rs
+++ b/src/server/ttl/ttl_compaction_filter.rs
@@ -60,7 +60,7 @@ impl CompactionFilter for TTLCompactionFilter {
             return CompactionFilterDecision::Keep;
         }
 
-        let expire_ts = get_expire_ts(&value).unwrap_or_else(|_| {
+        let expire_ts = get_expire_ts(value).unwrap_or_else(|_| {
             TTL_CHECKER_ACTIONS_COUNTER_VEC
                 .with_label_values(&["ts_error"])
                 .inc();
diff --git a/src/storage/mod.rs b/src/storage/mod.rs
index 57824a8cd6e..310daf87234 100644
--- a/src/storage/mod.rs
+++ b/src/storage/mod.rs
@@ -706,7 +706,7 @@ impl<E: Engine, L: LockManager> Storage<E, L> {
                         .read_range_check(Some(&start_key), end_key.as_ref(), |key, lock| {
                             Lock::check_ts_conflict(
                                 Cow::Borrowed(lock),
-                                &key,
+                                key,
                                 start_ts,
                                 &bypass_locks,
                             )
@@ -1186,12 +1186,13 @@ impl<E: Engine, L: LockManager> Storage<E, L> {
                 let store = RawStore::new(snapshot, enable_ttl);
                 {
                     let begin_instant = Instant::now_coarse();
-                    let keys: Vec<Key> = keys.into_iter().map(Key::from_encoded).collect();
+
                     let cf = Self::rawkv_cf(&cf)?;
                     // no scan_count for this kind of op.
                     let mut stats = Statistics::default();
                     let result: Vec<Result<KvPair>> = keys
                         .into_iter()
+                        .map(Key::from_encoded)
                         .map(|k| {
                             let v = store.raw_get_key_value(cf, &k, &mut stats);
                             (k, v)
@@ -1541,7 +1542,7 @@ impl<E: Engine, L: LockManager> Storage<E, L> {
                         let pairs: Vec<Result<KvPair>> = if reverse_scan {
                             store
                                 .reverse_raw_scan(
-                                    &cf,
+                                    cf,
                                     &start_key,
                                     end_key.as_ref(),
                                     each_limit,
@@ -1552,7 +1553,7 @@ impl<E: Engine, L: LockManager> Storage<E, L> {
                         } else {
                             store
                                 .forward_raw_scan(
-                                    &cf,
+                                    cf,
                                     &start_key,
                                     end_key.as_ref(),
                                     each_limit,
@@ -1802,8 +1803,8 @@ fn prepare_snap_ctx<'a>(
         let begin_instant = Instant::now();
         for key in keys.clone() {
             concurrency_manager
-                .read_key_check(&key, |lock| {
-                    Lock::check_ts_conflict(Cow::Borrowed(lock), &key, start_ts, bypass_locks)
+                .read_key_check(key, |lock| {
+                    Lock::check_ts_conflict(Cow::Borrowed(lock), key, start_ts, bypass_locks)
                 })
                 .map_err(|e| {
                     CHECK_MEM_LOCK_DURATION_HISTOGRAM_VEC
@@ -6252,7 +6253,7 @@ mod tests {
             .unwrap();
         let res = consumer.take_data();
         assert!(res[0].is_ok());
-        let key_error = extract_key_error(&res[1].as_ref().unwrap_err());
+        let key_error = extract_key_error(res[1].as_ref().unwrap_err());
         assert_eq!(key_error.get_locked().get_key(), b"key");
     }
 
diff --git a/src/storage/mvcc/consistency_check.rs b/src/storage/mvcc/consistency_check.rs
index 49f6a360196..087a24febb3 100644
--- a/src/storage/mvcc/consistency_check.rs
+++ b/src/storage/mvcc/consistency_check.rs
@@ -236,7 +236,7 @@ impl MvccInfoObserver for MvccInfoCollector {
             return Ok(false);
         }
 
-        let write = box_try!(WriteRef::parse(&value));
+        let write = box_try!(WriteRef::parse(value));
         let mut write_info = MvccWrite::default();
         match write.write_type {
             WriteType::Put => write_info.set_type(Op::Put),
@@ -246,7 +246,7 @@ impl MvccInfoObserver for MvccInfoCollector {
         }
         write_info.set_start_ts(write.start_ts.into_inner());
         write_info.set_commit_ts(commit_ts.into_inner());
-        if let Some(ref value) = write.short_value {
+        if let Some(value) = write.short_value {
             write_info.set_short_value(value.to_vec());
         }
 
@@ -373,7 +373,7 @@ impl MvccInfoObserver for MvccChecksum {
             return Ok(true);
         }
 
-        let write = box_try!(WriteRef::parse(&value));
+        let write = box_try!(WriteRef::parse(value));
         let start_ts = write.start_ts.into_inner();
 
         self.digest.update(key);
diff --git a/src/storage/mvcc/reader/reader.rs b/src/storage/mvcc/reader/reader.rs
index 49e65d0e495..f266a91a715 100644
--- a/src/storage/mvcc/reader/reader.rs
+++ b/src/storage/mvcc/reader/reader.rs
@@ -45,7 +45,7 @@ impl<S: EngineSnapshot> SnapshotReader<S> {
     pub fn key_exist(&mut self, key: &Key, ts: TimeStamp) -> Result<bool> {
         Ok(self
             .reader
-            .get_write(&key, ts, Some(self.start_ts))?
+            .get_write(key, ts, Some(self.start_ts))?
             .is_some())
     }
 
@@ -377,7 +377,7 @@ impl<S: EngineSnapshot> MvccReader<S> {
         self.create_lock_cursor()?;
         let cursor = self.lock_cursor.as_mut().unwrap();
         let ok = match start {
-            Some(ref x) => cursor.seek(x, &mut self.statistics.lock)?,
+            Some(x) => cursor.seek(x, &mut self.statistics.lock)?,
             None => cursor.seek_to_first(&mut self.statistics.lock),
         };
         if !ok {
@@ -545,7 +545,7 @@ pub mod tests {
     impl RegionEngine {
         pub fn new(db: &Arc<DB>, region: &Region) -> RegionEngine {
             RegionEngine {
-                db: Arc::clone(&db),
+                db: Arc::clone(db),
                 region: region.clone(),
             }
         }
@@ -878,7 +878,7 @@ pub mod tests {
         let path = dir.path().to_str().unwrap();
         let region = make_region(1, vec![0], vec![]);
 
-        let db = open_db(&path, true);
+        let db = open_db(path, true);
         let mut engine = RegionEngine::new(&db, &region);
 
         let key1 = &[1];
diff --git a/src/storage/raw/store.rs b/src/storage/raw/store.rs
index 0c37b4c8430..539134f250a 100644
--- a/src/storage/raw/store.rs
+++ b/src/storage/raw/store.rs
@@ -162,7 +162,7 @@ impl<'a, S: Snapshot> RawStoreInner<S> {
     ) -> Result<Vec<Result<KvPair>>> {
         let mut cursor = Cursor::new(self.snapshot.iter_cf(cf, option)?, ScanMode::Forward, false);
         let statistics = statistics.mut_cf_statistics(cf);
-        if !cursor.seek(&start_key, statistics)? {
+        if !cursor.seek(start_key, statistics)? {
             return Ok(vec![]);
         }
         let mut pairs = vec![];
@@ -210,7 +210,7 @@ impl<'a, S: Snapshot> RawStoreInner<S> {
             false,
         );
         let statistics = statistics.mut_cf_statistics(cf);
-        if !cursor.reverse_seek(&start_key, statistics)? {
+        if !cursor.reverse_seek(start_key, statistics)? {
             return Ok(vec![]);
         }
         let mut pairs = vec![];
diff --git a/src/storage/txn/actions/acquire_pessimistic_lock.rs b/src/storage/txn/actions/acquire_pessimistic_lock.rs
index c946d271b84..739a00dd8a3 100644
--- a/src/storage/txn/actions/acquire_pessimistic_lock.rs
+++ b/src/storage/txn/actions/acquire_pessimistic_lock.rs
@@ -63,7 +63,7 @@ pub fn acquire_pessimistic_lock<S: Snapshot>(
                 None => OldValue::None,
             })
         } else {
-            reader.get_old_value(&key, for_update_ts, prev_write_loaded, prev_write)
+            reader.get_old_value(key, for_update_ts, prev_write_loaded, prev_write)
         }
     }
 
diff --git a/src/storage/txn/actions/check_data_constraint.rs b/src/storage/txn/actions/check_data_constraint.rs
index d314a85739e..341f9a65d33 100644
--- a/src/storage/txn/actions/check_data_constraint.rs
+++ b/src/storage/txn/actions/check_data_constraint.rs
@@ -25,7 +25,7 @@ pub(crate) fn check_data_constraint<S: Snapshot>(
     // The current key exists under any of the following conditions:
     // 1.The current write type is `PUT`
     // 2.The current write type is `Rollback` or `Lock`, and the key have an older version.
-    if write.write_type == WriteType::Put || reader.key_exist(&key, write_commit_ts.prev())? {
+    if write.write_type == WriteType::Put || reader.key_exist(key, write_commit_ts.prev())? {
         return Err(ErrorInner::AlreadyExist { key: key.to_raw()? }.into());
     }
     Ok(())
diff --git a/src/storage/txn/actions/tests.rs b/src/storage/txn/actions/tests.rs
index ba85b9656cc..b25bf5491fc 100644
--- a/src/storage/txn/actions/tests.rs
+++ b/src/storage/txn/actions/tests.rs
@@ -58,7 +58,7 @@ pub fn must_prewrite_put_impl<E: Engine>(
             is_retry_request,
         },
         mutation,
-        &secondary_keys,
+        secondary_keys,
         is_pessimistic_lock,
     )
     .unwrap();
diff --git a/src/storage/txn/store.rs b/src/storage/txn/store.rs
index 4ef4d81b927..383f9cebc96 100644
--- a/src/storage/txn/store.rs
+++ b/src/storage/txn/store.rs
@@ -445,7 +445,7 @@ impl<S: Snapshot> SnapshotStore<S> {
                     REQUEST_EXCEED_BOUND.inc();
                     return Err(Error::from(ErrorInner::InvalidReqRange {
                         start: Some(l.as_encoded().clone()),
-                        end: upper_bound.as_ref().map(|ref b| b.as_encoded().clone()),
+                        end: upper_bound.as_ref().map(|b| b.as_encoded().clone()),
                         lower_bound: Some(b.to_vec()),
                         upper_bound: self.snapshot.upper_bound().map(|b| b.to_vec()),
                     }));
@@ -457,7 +457,7 @@ impl<S: Snapshot> SnapshotStore<S> {
                 if !b.is_empty() && (u.as_encoded().as_slice() > b || u.as_encoded().is_empty()) {
                     REQUEST_EXCEED_BOUND.inc();
                     return Err(Error::from(ErrorInner::InvalidReqRange {
-                        start: lower_bound.as_ref().map(|ref b| b.as_encoded().clone()),
+                        start: lower_bound.as_ref().map(|b| b.as_encoded().clone()),
                         end: Some(u.as_encoded().clone()),
                         lower_bound: self.snapshot.lower_bound().map(|b| b.to_vec()),
                         upper_bound: Some(b.to_vec()),
diff --git a/tests/benches/coprocessor_executors/util/fixture.rs b/tests/benches/coprocessor_executors/util/fixture.rs
index cd3fde92a9f..5588adbc672 100644
--- a/tests/benches/coprocessor_executors/util/fixture.rs
+++ b/tests/benches/coprocessor_executors/util/fixture.rs
@@ -232,7 +232,7 @@ impl FixtureBuilder {
         let mut store = Store::new();
         for row_index in 0..self.rows {
             store.begin();
-            let mut si = store.insert_into(&table);
+            let mut si = store.insert_into(table);
             for col_index in 0..columns.len() {
                 si = si.set(
                     &table[columns[col_index]],
diff --git a/tests/benches/hierarchy/engine/mod.rs b/tests/benches/hierarchy/engine/mod.rs
index c6f3d20f6f9..b9d87ade42a 100644
--- a/tests/benches/hierarchy/engine/mod.rs
+++ b/tests/benches/hierarchy/engine/mod.rs
@@ -23,7 +23,7 @@ fn bench_engine_put<E: Engine, F: EngineFactory<E>>(
             )
             .generate(DEFAULT_ITERATIONS)
             .iter()
-            .map(|(key, value)| (Key::from_raw(&key), value.clone()))
+            .map(|(key, value)| (Key::from_raw(key), value.clone()))
             .collect();
             (test_kvs, &ctx)
         },
@@ -61,7 +61,7 @@ fn bench_engine_get<E: Engine, F: EngineFactory<E>>(
     )
     .generate(DEFAULT_ITERATIONS)
     .iter()
-    .map(|(key, _)| Key::from_raw(&key))
+    .map(|(key, _)| Key::from_raw(key))
     .collect();
 
     bencher.iter_batched(
diff --git a/tests/benches/hierarchy/mvcc/mod.rs b/tests/benches/hierarchy/mvcc/mod.rs
index c8d77e04043..839204ef92f 100644
--- a/tests/benches/hierarchy/mvcc/mod.rs
+++ b/tests/benches/hierarchy/mvcc/mod.rs
@@ -51,7 +51,7 @@ where
             &mut txn,
             &mut reader,
             &txn_props,
-            Mutation::Put((Key::from_raw(&k), v.clone())),
+            Mutation::Put((Key::from_raw(k), v.clone())),
             &None,
             false,
         )
@@ -59,7 +59,7 @@ where
     }
     let write_data = WriteData::from_modifies(txn.into_modifies());
     let _ = engine.async_write(&ctx, write_data, Box::new(move |(..)| {}));
-    let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(&k)).collect();
+    let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(k)).collect();
     let snapshot = engine.snapshot(Default::default()).unwrap();
     (snapshot, keys)
 }
@@ -76,7 +76,7 @@ fn mvcc_prewrite<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config: &Bench
             )
             .generate(DEFAULT_ITERATIONS)
             .iter()
-            .map(|(k, v)| (Mutation::Put((Key::from_raw(&k), v.clone())), k.clone()))
+            .map(|(k, v)| (Mutation::Put((Key::from_raw(k), v.clone())), k.clone()))
             .collect();
             let snapshot = engine.snapshot(Default::default()).unwrap();
             (mutations, snapshot)
@@ -107,7 +107,7 @@ fn mvcc_commit<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config: &BenchCo
     let engine = config.engine_factory.build();
     let cm = ConcurrencyManager::new(1.into());
     b.iter_batched(
-        || setup_prewrite(&engine, &config, 1),
+        || setup_prewrite(&engine, config, 1),
         |(snapshot, keys)| {
             for key in keys {
                 let mut txn = mvcc::MvccTxn::new(1.into(), cm.clone());
@@ -126,7 +126,7 @@ fn mvcc_rollback_prewrote<E: Engine, F: EngineFactory<E>>(
     let engine = config.engine_factory.build();
     let cm = ConcurrencyManager::new(1.into());
     b.iter_batched(
-        || setup_prewrite(&engine, &config, 1),
+        || setup_prewrite(&engine, config, 1),
         |(snapshot, keys)| {
             for key in keys {
                 let mut txn = mvcc::MvccTxn::new(1.into(), cm.clone());
@@ -152,7 +152,7 @@ fn mvcc_rollback_conflict<E: Engine, F: EngineFactory<E>>(
     let engine = config.engine_factory.build();
     let cm = ConcurrencyManager::new(1.into());
     b.iter_batched(
-        || setup_prewrite(&engine, &config, 2),
+        || setup_prewrite(&engine, config, 2),
         |(snapshot, keys)| {
             for key in keys {
                 let mut txn = mvcc::MvccTxn::new(1.into(), cm.clone());
@@ -185,7 +185,7 @@ fn mvcc_rollback_non_prewrote<E: Engine, F: EngineFactory<E>>(
                 DEFAULT_KV_GENERATOR_SEED,
             )
             .generate(DEFAULT_ITERATIONS);
-            let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(&k)).collect();
+            let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(k)).collect();
             let snapshot = engine.snapshot(Default::default()).unwrap();
             (snapshot, keys)
         },
@@ -216,7 +216,7 @@ fn mvcc_reader_load_lock<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config
     )
     .generate(DEFAULT_ITERATIONS)
     .iter()
-    .map(|(k, _)| Key::from_raw(&k))
+    .map(|(k, _)| Key::from_raw(k))
     .collect();
 
     b.iter_batched(
@@ -227,7 +227,7 @@ fn mvcc_reader_load_lock<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config
         |(snapshot, test_kvs)| {
             for key in test_kvs {
                 let mut reader = MvccReader::new(snapshot.clone(), None, true);
-                black_box(reader.load_lock(&key).unwrap());
+                black_box(reader.load_lock(key).unwrap());
             }
         },
         BatchSize::SmallInput,
@@ -249,14 +249,14 @@ fn mvcc_reader_seek_write<E: Engine, F: EngineFactory<E>>(
             )
             .generate(DEFAULT_ITERATIONS)
             .iter()
-            .map(|(k, _)| Key::from_raw(&k))
+            .map(|(k, _)| Key::from_raw(k))
             .collect();
             (snapshot, test_keys)
         },
         |(snapshot, test_keys)| {
             for key in &test_keys {
                 let mut reader = MvccReader::new(snapshot.clone(), None, true);
-                black_box(reader.seek_write(&key, TimeStamp::max()).unwrap());
+                black_box(reader.seek_write(key, TimeStamp::max()).unwrap());
             }
         },
         BatchSize::SmallInput,
diff --git a/tests/benches/hierarchy/storage/mod.rs b/tests/benches/hierarchy/storage/mod.rs
index 920496b4a46..8a1644fc45c 100644
--- a/tests/benches/hierarchy/storage/mod.rs
+++ b/tests/benches/hierarchy/storage/mod.rs
@@ -45,7 +45,7 @@ fn storage_prewrite<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config: &Be
                 .map(|(k, v)| {
                     (
                         Context::default(),
-                        vec![Mutation::Put((Key::from_raw(&k), v.clone()))],
+                        vec![Mutation::Put((Key::from_raw(k), v.clone()))],
                         k.clone(),
                     )
                 })
@@ -73,7 +73,7 @@ fn storage_commit<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config: &Benc
                 store
                     .prewrite(
                         Context::default(),
-                        vec![Mutation::Put((Key::from_raw(&k), v.clone()))],
+                        vec![Mutation::Put((Key::from_raw(k), v.clone()))],
                         k.clone(),
                         1,
                     )
diff --git a/tests/benches/hierarchy/txn/mod.rs b/tests/benches/hierarchy/txn/mod.rs
index dac48fb352c..c8e5ca64dc2 100644
--- a/tests/benches/hierarchy/txn/mod.rs
+++ b/tests/benches/hierarchy/txn/mod.rs
@@ -47,7 +47,7 @@ where
             &mut txn,
             &mut reader,
             &txn_props,
-            Mutation::Put((Key::from_raw(&k), v.clone())),
+            Mutation::Put((Key::from_raw(k), v.clone())),
             &None,
             false,
         )
@@ -55,7 +55,7 @@ where
     }
     let write_data = WriteData::from_modifies(txn.into_modifies());
     let _ = engine.write(&ctx, write_data);
-    let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(&k)).collect();
+    let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(k)).collect();
     keys
 }
 
@@ -69,7 +69,7 @@ fn txn_prewrite<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config: &BenchC
                 KvGenerator::new(config.key_length, config.value_length)
                     .generate(DEFAULT_ITERATIONS)
                     .iter()
-                    .map(|(k, v)| (Mutation::Put((Key::from_raw(&k), v.clone())), k.clone()))
+                    .map(|(k, v)| (Mutation::Put((Key::from_raw(k), v.clone())), k.clone()))
                     .collect();
             mutations
         },
@@ -103,7 +103,7 @@ fn txn_commit<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config: &BenchCon
     let ctx = Context::default();
     let cm = ConcurrencyManager::new(1.into());
     b.iter_batched(
-        || setup_prewrite(&engine, &config, 1),
+        || setup_prewrite(&engine, config, 1),
         |keys| {
             for key in keys {
                 let snapshot = engine.snapshot(Default::default()).unwrap();
@@ -123,7 +123,7 @@ fn txn_rollback_prewrote<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config
     let ctx = Context::default();
     let cm = ConcurrencyManager::new(1.into());
     b.iter_batched(
-        || setup_prewrite(&engine, &config, 1),
+        || setup_prewrite(&engine, config, 1),
         |keys| {
             for key in keys {
                 let snapshot = engine.snapshot(Default::default()).unwrap();
@@ -143,7 +143,7 @@ fn txn_rollback_conflict<E: Engine, F: EngineFactory<E>>(b: &mut Bencher, config
     let ctx = Context::default();
     let cm = ConcurrencyManager::new(1.into());
     b.iter_batched(
-        || setup_prewrite(&engine, &config, 2),
+        || setup_prewrite(&engine, config, 2),
         |keys| {
             for key in keys {
                 let snapshot = engine.snapshot(Default::default()).unwrap();
@@ -169,7 +169,7 @@ fn txn_rollback_non_prewrote<E: Engine, F: EngineFactory<E>>(
         || {
             let kvs = KvGenerator::new(config.key_length, config.value_length)
                 .generate(DEFAULT_ITERATIONS);
-            let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(&k)).collect();
+            let keys: Vec<Key> = kvs.iter().map(|(k, _)| Key::from_raw(k)).collect();
             keys
         },
         |keys| {
diff --git a/tests/failpoints/cases/test_gc_worker.rs b/tests/failpoints/cases/test_gc_worker.rs
index c63ef706130..4b3dbf59bbb 100644
--- a/tests/failpoints/cases/test_gc_worker.rs
+++ b/tests/failpoints/cases/test_gc_worker.rs
@@ -249,7 +249,7 @@ fn test_collect_applying_locks() {
 
     // Write 1 lock.
     must_kv_prewrite(
-        &store_1_client,
+        store_1_client,
         ctx,
         vec![new_mutation(Op::Put, b"k1", b"v")],
         b"k1".to_vec(),