diff --git a/src/primitives/bitcoin/merkleblock.cpp b/src/primitives/bitcoin/merkleblock.cpp
index 9a34898501..09b90be5da 100644
--- a/src/primitives/bitcoin/merkleblock.cpp
+++ b/src/primitives/bitcoin/merkleblock.cpp
@@ -55,7 +55,7 @@ uint256 CPartialMerkleTree::CalcHash(int height, unsigned int pos, const std::ve
         else
             right = left;
         // combine subhashes
-        return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
+        return Hash(left.begin(), left.end(), right.begin(), right.end());
     }
 }
 
@@ -111,7 +111,7 @@ uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, uns
             right = left;
         }
         // and combine them before returning
-        return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
+        return Hash(left.begin(), left.end(), right.begin(), right.end());
     }
 }
 
diff --git a/src/primitives/bitcoin/transaction.h b/src/primitives/bitcoin/transaction.h
index 751a4556e4..12d5cab39e 100644
--- a/src/primitives/bitcoin/transaction.h
+++ b/src/primitives/bitcoin/transaction.h
@@ -24,7 +24,9 @@ class COutPoint
     uint256 hash;
     uint32_t n;
 
-    COutPoint(): n((uint32_t) -1) { }
+    static constexpr uint32_t NULL_INDEX = std::numeric_limits<uint32_t>::max();
+
+    COutPoint(): n(NULL_INDEX) { }
     COutPoint(const uint256& hashIn, uint32_t nIn): hash(hashIn), n(nIn) { }
 
     ADD_SERIALIZE_METHODS;
@@ -35,8 +37,8 @@ class COutPoint
         READWRITE(n);
     }
 
-    void SetNull() { hash.SetNull(); n = (uint32_t) -1; }
-    bool IsNull() const { return (hash.IsNull() && n == (uint32_t) -1); }
+    void SetNull() { hash.SetNull(); n = NULL_INDEX; }
+    bool IsNull() const { return (hash.IsNull() && n == NULL_INDEX); }
 
     friend bool operator<(const COutPoint& a, const COutPoint& b)
     {
@@ -67,7 +69,7 @@ class CTxIn
     COutPoint prevout;
     CScript scriptSig;
     uint32_t nSequence;
-    CScriptWitness scriptWitness; //! Only serialized through CTransaction
+    CScriptWitness scriptWitness; //!< Only serialized through CTransaction
 
     /* Setting nSequence to this value for every input in a transaction
      * disables nLockTime. */
@@ -76,7 +78,7 @@ class CTxIn
     /* Below flags apply in the context of BIP 68*/
     /* If this flag set, CTxIn::nSequence is NOT interpreted as a
      * relative lock-time. */
-    static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31);
+    static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1U << 31);
 
     /* If CTxIn::nSequence encodes a relative lock-time and this flag
      * is set, the relative lock-time has units of 512 seconds,
@@ -299,7 +301,7 @@ class CTransaction
     CTransaction();
 
     /** Convert a CMutableTransaction into a CTransaction. */
-    CTransaction(const CMutableTransaction &tx);
+    explicit CTransaction(const CMutableTransaction &tx);
     CTransaction(CMutableTransaction &&tx);
 
     template <typename Stream>