diff --git a/src/app.rs b/src/app.rs
index 0e4f275..b03f50d 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -45,7 +45,7 @@ impl App {
         let mut tip = self.tip.lock().expect("failed to lock tip");
         let new_block = *tip != self.daemon().getbestblockhash()?;
         if new_block {
-            *tip = self.index().update(self.write_store(), &signal)?;
+            *tip = self.index().update(self.write_store(), signal)?;
         }
         Ok(new_block)
     }
diff --git a/src/cache.rs b/src/cache.rs
index 7c7e13c..7b2a5b0 100644
--- a/src/cache.rs
+++ b/src/cache.rs
@@ -129,7 +129,7 @@ impl TransactionCache {
         F: FnOnce() -> Result<Vec<u8>>,
     {
         if let Some(serialized_txn) = self.map.lock().unwrap().get(txid) {
-            return Ok(deserialize(&serialized_txn).chain_err(|| "failed to parse cached tx")?);
+            return Ok(deserialize(serialized_txn).chain_err(|| "failed to parse cached tx")?);
         }
         let serialized_txn = load_txn_func()?;
         let txn = deserialize(&serialized_txn).chain_err(|| "failed to parse serialized tx")?;
diff --git a/src/daemon.rs b/src/daemon.rs
index e670158..f058797 100644
--- a/src/daemon.rs
+++ b/src/daemon.rs
@@ -513,7 +513,7 @@ impl Daemon {
 
     pub fn getblocktxids(&self, blockhash: &BlockHash) -> Result<Vec<Txid>> {
         self.blocktxids_cache
-            .get_or_else(&blockhash, || self.load_blocktxids(blockhash))
+            .get_or_else(blockhash, || self.load_blocktxids(blockhash))
     }
 
     pub fn gettransaction(
@@ -545,7 +545,7 @@ impl Daemon {
         let txids: Value = self.request("getrawmempool", json!([/*verbose=*/ false]))?;
         let mut result = HashSet::new();
         for value in txids.as_array().chain_err(|| "non-array result")? {
-            result.insert(parse_hash(&value).chain_err(|| "invalid txid")?);
+            result.insert(parse_hash(value).chain_err(|| "invalid txid")?);
         }
         Ok(result)
     }
@@ -589,7 +589,7 @@ impl Daemon {
         let null_hash = BlockHash::default();
         for heights in all_heights.chunks(chunk_size) {
             trace!("downloading {} block headers", heights.len());
-            let mut headers = self.getblockheaders(&heights)?;
+            let mut headers = self.getblockheaders(heights)?;
             assert!(headers.len() == heights.len());
             result.append(&mut headers);
         }
diff --git a/src/index.rs b/src/index.rs
index bb63d3e..f4473e0 100644
--- a/src/index.rs
+++ b/src/index.rs
@@ -176,13 +176,13 @@ pub fn index_transaction<'a>(
         if input.previous_output.txid == null_hash {
             None
         } else {
-            Some(TxInRow::new(&txid, &input).to_row())
+            Some(TxInRow::new(&txid, input).to_row())
         }
     });
     let outputs = txn
         .output
         .iter()
-        .map(move |output| TxOutRow::new(&txid, &output).to_row());
+        .map(move |output| TxOutRow::new(&txid, output).to_row());
 
     // Persist transaction ID and confirmed height
     inputs
@@ -204,7 +204,7 @@ pub fn index_block<'a>(block: &'a Block, height: usize) -> impl 'a + Iterator<It
     block
         .txdata
         .iter()
-        .flat_map(move |txn| index_transaction(&txn, height))
+        .flat_map(move |txn| index_transaction(txn, height))
         .chain(std::iter::once(row))
 }
 
diff --git a/src/metrics.rs b/src/metrics.rs
index b2c98cc..68ca980 100644
--- a/src/metrics.rs
+++ b/src/metrics.rs
@@ -75,7 +75,7 @@ impl Metrics {
                 self.addr, e
             )
         });
-        start_process_exporter(&self);
+        start_process_exporter(self);
         let reg = self.reg.clone();
         spawn_thread("metrics", move || loop {
             if let Err(e) = handle_request(&reg, server.recv()) {
diff --git a/src/query.rs b/src/query.rs
index b4838e5..038da53 100644
--- a/src/query.rs
+++ b/src/query.rs
@@ -165,7 +165,7 @@ fn create_merkle_branch_and_root<T: Hash>(mut hashes: Vec<T>, mut index: usize)
 
 // TODO: the functions below can be part of ReadStore.
 fn txrow_by_txid(store: &dyn ReadStore, txid: &Txid) -> Option<TxRow> {
-    let key = TxRow::filter_full(&txid);
+    let key = TxRow::filter_full(txid);
     let value = store.get(&key)?;
     Some(TxRow::from_row(&Row { key, value }))
 }
@@ -192,7 +192,7 @@ fn txids_by_funding_output(
     output_index: usize,
 ) -> Vec<HashPrefix> {
     store
-        .scan(&TxInRow::filter(&txn_id, output_index))
+        .scan(&TxInRow::filter(txn_id, output_index))
         .iter()
         .map(|row| TxInRow::from_row(row).txid_prefix)
         .collect()
@@ -311,7 +311,7 @@ impl Query {
             funding.extend(self.find_funding_outputs(&t, script_hash));
         }
         for funding_output in &funding {
-            if let Some(spent) = self.find_spending_input(read_store, &funding_output)? {
+            if let Some(spent) = self.find_spending_input(read_store, funding_output)? {
                 spending.push(spent);
             }
         }
@@ -332,7 +332,7 @@ impl Query {
         }
         // // TODO: dedup outputs (somehow) both confirmed and in mempool (e.g. reorg?)
         for funding_output in funding.iter().chain(confirmed_funding.iter()) {
-            if let Some(spent) = self.find_spending_input(tracker.index(), &funding_output)? {
+            if let Some(spent) = self.find_spending_input(tracker.index(), funding_output)? {
                 spending.push(spent);
             }
         }
@@ -380,14 +380,14 @@ impl Query {
         tx_hash: &Txid,
         block_height: Option<u32>,
     ) -> Result<Option<BlockHash>> {
-        let blockhash = if self.tracker.read().unwrap().has_txn(&tx_hash) {
+        let blockhash = if self.tracker.read().unwrap().has_txn(tx_hash) {
             None // found in mempool (as unconfirmed transaction)
         } else {
             // Lookup in confirmed transactions' index
             let height = match block_height {
                 Some(height) => height,
                 None => {
-                    txrow_by_txid(self.app.read_store(), &tx_hash)
+                    txrow_by_txid(self.app.read_store(), tx_hash)
                         .chain_err(|| format!("not indexed tx {}", tx_hash))?
                         .height
                 }
@@ -405,7 +405,7 @@ impl Query {
     // Internal API for transaction retrieval
     fn load_txn(&self, txid: &Txid, block_height: Option<u32>) -> Result<Transaction> {
         let _timer = self.duration.with_label_values(&["load_txn"]).start_timer();
-        self.tx_cache.get_or_else(&txid, || {
+        self.tx_cache.get_or_else(txid, || {
             let blockhash = self.lookup_confirmed_blockhash(txid, block_height)?;
             let value: Value = self
                 .app
@@ -460,7 +460,7 @@ impl Query {
             .index()
             .get_header(height)
             .chain_err(|| format!("missing block #{}", height))?;
-        let txids = self.app.daemon().getblocktxids(&header_entry.hash())?;
+        let txids = self.app.daemon().getblocktxids(header_entry.hash())?;
         let pos = txids
             .iter()
             .position(|txid| txid == tx_hash)
diff --git a/src/rpc.rs b/src/rpc.rs
index 257d84a..2b44938 100644
--- a/src/rpc.rs
+++ b/src/rpc.rs
@@ -367,24 +367,22 @@ impl Connection {
             .with_label_values(&[method])
             .start_timer();
         let result = match method {
-            "blockchain.block.header" => self.blockchain_block_header(&params),
-            "blockchain.block.headers" => self.blockchain_block_headers(&params),
-            "blockchain.estimatefee" => self.blockchain_estimatefee(&params),
+            "blockchain.block.header" => self.blockchain_block_header(params),
+            "blockchain.block.headers" => self.blockchain_block_headers(params),
+            "blockchain.estimatefee" => self.blockchain_estimatefee(params),
             "blockchain.headers.subscribe" => self.blockchain_headers_subscribe(),
             "blockchain.relayfee" => self.blockchain_relayfee(),
-            "blockchain.scripthash.get_balance" => self.blockchain_scripthash_get_balance(&params),
-            "blockchain.scripthash.get_history" => self.blockchain_scripthash_get_history(&params),
-            "blockchain.scripthash.listunspent" => self.blockchain_scripthash_listunspent(&params),
-            "blockchain.scripthash.subscribe" => self.blockchain_scripthash_subscribe(&params),
-            "blockchain.transaction.broadcast" => self.blockchain_transaction_broadcast(&params),
-            "blockchain.transaction.get" => self.blockchain_transaction_get(&params),
-            "blockchain.transaction.get_merkle" => self.blockchain_transaction_get_merkle(&params),
+            "blockchain.scripthash.get_balance" => self.blockchain_scripthash_get_balance(params),
+            "blockchain.scripthash.get_history" => self.blockchain_scripthash_get_history(params),
+            "blockchain.scripthash.listunspent" => self.blockchain_scripthash_listunspent(params),
+            "blockchain.scripthash.subscribe" => self.blockchain_scripthash_subscribe(params),
+            "blockchain.transaction.broadcast" => self.blockchain_transaction_broadcast(params),
+            "blockchain.transaction.get" => self.blockchain_transaction_get(params),
+            "blockchain.transaction.get_merkle" => self.blockchain_transaction_get_merkle(params),
             "blockchain.transaction.get_confirmed_blockhash" => {
-                self.blockchain_transaction_get_confirmed_blockhash(&params)
-            }
-            "blockchain.transaction.id_from_pos" => {
-                self.blockchain_transaction_id_from_pos(&params)
+                self.blockchain_transaction_get_confirmed_blockhash(params)
             }
+            "blockchain.transaction.id_from_pos" => self.blockchain_transaction_id_from_pos(params),
             "mempool.get_fee_histogram" => self.mempool_get_fee_histogram(),
             "server.banner" => self.server_banner(),
             "server.donation_address" => self.server_donation_address(),