diff --git a/src/fs.cpp b/src/fs.cpp
index e68c97b3caf..eef9c81de92 100644
--- a/src/fs.cpp
+++ b/src/fs.cpp
@@ -5,10 +5,12 @@
 #include <fs.h>
 
 #ifndef WIN32
+#include <cstring>
 #include <fcntl.h>
 #include <string>
 #include <sys/file.h>
 #include <sys/utsname.h>
+#include <unistd.h>
 #else
 #ifndef NOMINMAX
 #define NOMINMAX
@@ -31,7 +33,8 @@ FILE *fopen(const fs::path& p, const char *mode)
 
 #ifndef WIN32
 
-static std::string GetErrorReason() {
+static std::string GetErrorReason()
+{
     return std::strerror(errno);
 }
 
diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index 61d7ddb9340..65695707f75 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -8,6 +8,7 @@
 #include <optional.h>               // For Optional and nullopt
 #include <primitives/transaction.h> // For CTransactionRef
 
+#include <functional>
 #include <memory>
 #include <stddef.h>
 #include <stdint.h>
diff --git a/src/qt/coincontroldialog.cpp b/src/qt/coincontroldialog.cpp
index db77c17df0b..f44a9f285ae 100644
--- a/src/qt/coincontroldialog.cpp
+++ b/src/qt/coincontroldialog.cpp
@@ -400,7 +400,6 @@ void CoinControlDialog::updateLabels(CCoinControl& m_coin_control, WalletModel *
     // nPayAmount
     CAmount nPayAmount = 0;
     bool fDust = false;
-    CMutableTransaction txDummy;
     for (const CAmount &amount : CoinControlDialog::payAmounts)
     {
         nPayAmount += amount;
@@ -409,7 +408,6 @@ void CoinControlDialog::updateLabels(CCoinControl& m_coin_control, WalletModel *
         {
             // Assumes a p2pkh script size
             CTxOut txout(amount, CScript() << std::vector<unsigned char>(24, 0));
-            txDummy.vout.push_back(txout);
             fDust |= IsDust(txout, model->node().getDustRelayFee());
         }
     }
diff --git a/src/qt/transactionrecord.cpp b/src/qt/transactionrecord.cpp
index 01dff8069c0..52007ef350f 100644
--- a/src/qt/transactionrecord.cpp
+++ b/src/qt/transactionrecord.cpp
@@ -47,7 +47,6 @@ QList<TransactionRecord> TransactionRecord::decomposeTransaction(const interface
             if(mine)
             {
                 TransactionRecord sub(hash, nTime);
-                CTxDestination address;
                 sub.idx = i; // vout index
                 sub.credit = txout.nValue;
                 sub.involvesWatchAddress = mine & ISMINE_WATCH_ONLY;
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 567c91a45da..cf42c1cb3c3 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -746,7 +746,6 @@ void CWallet::SetSpentKeyState(WalletBatch& batch, const uint256& hash, unsigned
 bool CWallet::IsSpentKey(const uint256& hash, unsigned int n) const
 {
     AssertLockHeld(cs_wallet);
-    CTxDestination dst;
     const CWalletTx* srctx = GetWalletTx(hash);
     if (srctx) {
         assert(srctx->tx->vout.size() > n);