diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -216,7 +216,7 @@
         coinControlUpdateLabels();
 
         // fee section
-        for (const int &n : confTargets) {
+        for (const int n : confTargets) {
             ui->confTargetSelector->addItem(
                 tr("%1 (%2 blocks)")
                     .arg(GUIUtil::formatNiceTimeOffset(
diff --git a/src/streams.h b/src/streams.h
--- a/src/streams.h
+++ b/src/streams.h
@@ -222,10 +222,10 @@
         vch.clear();
         nReadPos = 0;
     }
-    iterator insert(iterator it, const char &x = char()) {
+    iterator insert(iterator it, const char x = char()) {
         return vch.insert(it, x);
     }
-    void insert(iterator it, size_type n, const char &x) {
+    void insert(iterator it, size_type n, const char x) {
         vch.insert(it, n, x);
     }
     value_type *data() { return vch.data() + nReadPos; }
diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -885,9 +885,9 @@
             data.exists("pubkeys") ? data["pubkeys"].get_array() : UniValue();
         const UniValue &keys =
             data.exists("keys") ? data["keys"].get_array() : UniValue();
-        const bool &internal =
+        const bool internal =
             data.exists("internal") ? data["internal"].get_bool() : false;
-        const bool &watchOnly =
+        const bool watchOnly =
             data.exists("watchonly") ? data["watchonly"].get_bool() : false;
         const std::string &label =
             data.exists("label") && !internal ? data["label"].get_str() : "";
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -430,8 +430,8 @@
     Amount GetCredit(const isminefilter &filter) const;
     Amount GetImmatureCredit(bool fUseCache = true) const;
     Amount GetAvailableCredit(bool fUseCache = true) const;
-    Amount GetImmatureWatchOnlyCredit(const bool &fUseCache = true) const;
-    Amount GetAvailableWatchOnlyCredit(const bool &fUseCache = true) const;
+    Amount GetImmatureWatchOnlyCredit(const bool fUseCache = true) const;
+    Amount GetAvailableWatchOnlyCredit(const bool fUseCache = true) const;
     Amount GetChange() const;
 
     void GetAmounts(std::list<COutputEntry> &listReceived,
@@ -830,9 +830,9 @@
                         const Amount nMinimumAmount = SATOSHI,
                         const Amount nMaximumAmount = MAX_MONEY,
                         const Amount nMinimumSumAmount = MAX_MONEY,
-                        const uint64_t &nMaximumCount = 0,
-                        const int &nMinDepth = 0,
-                        const int &nMaxDepth = 9999999) const;
+                        const uint64_t nMaximumCount = 0,
+                        const int nMinDepth = 0,
+                        const int nMaxDepth = 9999999) const;
 
     /**
      * Return list of available coins and locked coins grouped by non-change
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1963,7 +1963,7 @@
     return nCredit;
 }
 
-Amount CWalletTx::GetImmatureWatchOnlyCredit(const bool &fUseCache) const {
+Amount CWalletTx::GetImmatureWatchOnlyCredit(const bool fUseCache) const {
     if (IsImmatureCoinBase() && IsInMainChain()) {
         if (fUseCache && fImmatureWatchCreditCached) {
             return nImmatureWatchCreditCached;
@@ -1978,7 +1978,7 @@
     return Amount::zero();
 }
 
-Amount CWalletTx::GetAvailableWatchOnlyCredit(const bool &fUseCache) const {
+Amount CWalletTx::GetAvailableWatchOnlyCredit(const bool fUseCache) const {
     if (pwallet == nullptr) {
         return Amount::zero();
     }
@@ -2294,8 +2294,8 @@
                              const Amount nMinimumAmount,
                              const Amount nMaximumAmount,
                              const Amount nMinimumSumAmount,
-                             const uint64_t &nMaximumCount,
-                             const int &nMinDepth, const int &nMaxDepth) const {
+                             const uint64_t nMaximumCount, const int nMinDepth,
+                             const int nMaxDepth) const {
     vCoins.clear();
     Amount nTotal = Amount::zero();