diff --git a/src/chain.h b/src/chain.h
index 7e84c3240..b17dda56e 100644
--- a/src/chain.h
+++ b/src/chain.h
@@ -1,444 +1,419 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_CHAIN_H
 #define BITCOIN_CHAIN_H
 
 #include <arith_uint256.h>
 #include <blockstatus.h>
 #include <blockvalidity.h>
 #include <consensus/params.h>
 #include <crypto/common.h> // for ReadLE64
 #include <flatfile.h>
 #include <primitives/block.h>
 #include <sync.h>
 #include <tinyformat.h>
 #include <uint256.h>
 
 #include <unordered_map>
 #include <vector>
 
 /**
  * Maximum amount of time that a block timestamp is allowed to exceed the
  * current network-adjusted time before the block will be accepted.
  */
 static constexpr int64_t MAX_FUTURE_BLOCK_TIME = 2 * 60 * 60;
 
 /**
  * Timestamp window used as a grace period by code that compares external
  * timestamps (such as timestamps passed to RPCs, or wallet key creation times)
  * to block timestamps. This should be set at least as high as
  * MAX_FUTURE_BLOCK_TIME.
  */
 static constexpr int64_t TIMESTAMP_WINDOW = MAX_FUTURE_BLOCK_TIME;
 
 /**
  * Maximum gap between node time and block time used
  * for the "Catching up..." mode in GUI.
  *
  * Ref: https://github.com/bitcoin/bitcoin/pull/1026
  */
 static constexpr int64_t MAX_BLOCK_TIME_GAP = 90 * 60;
 
 /**
  * The block chain is a tree shaped structure starting with the genesis block at
  * the root, with each block potentially having multiple candidates to be the
  * next block. A blockindex may have multiple pprev pointing to it, but at most
  * one of them can be part of the currently active branch.
  */
 class CBlockIndex {
 public:
     //! pointer to the hash of the block, if any. Memory is owned by this
     //! CBlockIndex
-    const BlockHash *phashBlock;
+    const BlockHash *phashBlock = nullptr;
 
     //! pointer to the index of the predecessor of this block
-    CBlockIndex *pprev;
+    CBlockIndex *pprev = nullptr;
 
     //! pointer to the index of some further predecessor of this block
-    CBlockIndex *pskip;
+    CBlockIndex *pskip = nullptr;
 
     //! height of the entry in the chain. The genesis block has height 0
-    int nHeight;
+    int nHeight = 0;
 
     //! Which # file this block is stored in (blk?????.dat)
-    int nFile;
+    int nFile = 0;
 
     //! Byte offset within blk?????.dat where this block's data is stored
-    unsigned int nDataPos;
+    unsigned int nDataPos = 0;
 
     //! Byte offset within rev?????.dat where this block's undo data is stored
-    unsigned int nUndoPos;
+    unsigned int nUndoPos = 0;
 
     //! (memory only) Total amount of work (expected number of hashes) in the
     //! chain up to and including this block
-    arith_uint256 nChainWork;
+    arith_uint256 nChainWork = arith_uint256();
 
     //! Number of transactions in this block.
     //! Note: in a potential headers-first mode, this number cannot be relied
     //! upon
-    unsigned int nTx;
+    unsigned int nTx = 0;
 
     //! (memory only) Number of transactions in the chain up to and including
     //! this block.
     //! This value will be non-zero only if and only if transactions for this
     //! block and all its parents are available. Change to 64-bit type when
     //! necessary; won't happen before 2030
-    unsigned int nChainTx;
+    unsigned int nChainTx = 0;
 
     //! Verification status of this block. See enum BlockStatus
-    BlockStatus nStatus;
+    BlockStatus nStatus = BlockStatus();
 
     //! block header
-    int32_t nVersion;
-    uint256 hashMerkleRoot;
-    uint32_t nTime;
-    uint32_t nBits;
-    uint32_t nNonce;
+    int32_t nVersion = 0;
+    uint256 hashMerkleRoot = uint256();
+    uint32_t nTime = 0;
+    uint32_t nBits = 0;
+    uint32_t nNonce = 0;
 
     //! (memory only) Sequential id assigned to distinguish order in which
     //! blocks are received.
-    int32_t nSequenceId;
+    int32_t nSequenceId = 0;
 
     //! (memory only) block header metadata
-    uint64_t nTimeReceived;
+    uint64_t nTimeReceived = 0;
 
     //! (memory only) Maximum nTime in the chain up to and including this block.
-    unsigned int nTimeMax;
-
-    void SetNull() {
-        phashBlock = nullptr;
-        pprev = nullptr;
-        pskip = nullptr;
-        nHeight = 0;
-        nFile = 0;
-        nDataPos = 0;
-        nUndoPos = 0;
-        nChainWork = arith_uint256();
-        nTx = 0;
-        nChainTx = 0;
-        nStatus = BlockStatus();
-        nSequenceId = 0;
-        nTimeMax = 0;
-
-        nVersion = 0;
-        hashMerkleRoot = uint256();
-        nTime = 0;
-        nTimeReceived = 0;
-        nBits = 0;
-        nNonce = 0;
-    }
-
-    CBlockIndex() { SetNull(); }
+    unsigned int nTimeMax = 0;
 
-    explicit CBlockIndex(const CBlockHeader &block) {
-        SetNull();
+    explicit CBlockIndex() = default;
 
+    explicit CBlockIndex(const CBlockHeader &block) : CBlockIndex() {
         nVersion = block.nVersion;
         hashMerkleRoot = block.hashMerkleRoot;
         nTime = block.nTime;
         nTimeReceived = 0;
         nBits = block.nBits;
         nNonce = block.nNonce;
     }
 
     FlatFilePos GetBlockPos() const {
         FlatFilePos ret;
         if (nStatus.hasData()) {
             ret.nFile = nFile;
             ret.nPos = nDataPos;
         }
         return ret;
     }
 
     FlatFilePos GetUndoPos() const {
         FlatFilePos ret;
         if (nStatus.hasUndo()) {
             ret.nFile = nFile;
             ret.nPos = nUndoPos;
         }
         return ret;
     }
 
     CBlockHeader GetBlockHeader() const {
         CBlockHeader block;
         block.nVersion = nVersion;
         if (pprev) {
             block.hashPrevBlock = pprev->GetBlockHash();
         }
         block.hashMerkleRoot = hashMerkleRoot;
         block.nTime = nTime;
         block.nBits = nBits;
         block.nNonce = nNonce;
         return block;
     }
 
     BlockHash GetBlockHash() const { return *phashBlock; }
 
     /**
      * Check whether this block's and all previous blocks' transactions have
      * been downloaded (and stored to disk) at some point.
      *
      * Does not imply the transactions are consensus-valid (ConnectTip might
      * fail) Does not imply the transactions are still stored on disk.
      * (IsBlockPruned might return true)
      */
     bool HaveTxsDownloaded() const { return nChainTx != 0; }
 
     int64_t GetBlockTime() const { return int64_t(nTime); }
 
     int64_t GetBlockTimeMax() const { return int64_t(nTimeMax); }
 
     int64_t GetHeaderReceivedTime() const { return nTimeReceived; }
 
     int64_t GetReceivedTimeDiff() const {
         return GetHeaderReceivedTime() - GetBlockTime();
     }
 
     static constexpr int nMedianTimeSpan = 11;
 
     int64_t GetMedianTimePast() const {
         int64_t pmedian[nMedianTimeSpan];
         int64_t *pbegin = &pmedian[nMedianTimeSpan];
         int64_t *pend = &pmedian[nMedianTimeSpan];
 
         const CBlockIndex *pindex = this;
         for (int i = 0; i < nMedianTimeSpan && pindex;
              i++, pindex = pindex->pprev) {
             *(--pbegin) = pindex->GetBlockTime();
         }
 
         std::sort(pbegin, pend);
         return pbegin[(pend - pbegin) / 2];
     }
 
     std::string ToString() const {
         return strprintf(
             "CBlockIndex(pprev=%p, nHeight=%d, merkle=%s, hashBlock=%s)", pprev,
             nHeight, hashMerkleRoot.ToString(), GetBlockHash().ToString());
     }
 
     //! Check whether this block index entry is valid up to the passed validity
     //! level.
     bool IsValid(enum BlockValidity nUpTo = BlockValidity::TRANSACTIONS) const {
         return nStatus.isValid(nUpTo);
     }
 
     //! Raise the validity level of this block index entry.
     //! Returns true if the validity was changed.
     bool RaiseValidity(enum BlockValidity nUpTo) {
         // Only validity flags allowed.
         if (nStatus.isInvalid()) {
             return false;
         }
 
         if (nStatus.getValidity() >= nUpTo) {
             return false;
         }
 
         nStatus = nStatus.withValidity(nUpTo);
         return true;
     }
 
     //! Build the skiplist pointer for this entry.
     void BuildSkip();
 
     //! Efficiently find an ancestor of this block.
     CBlockIndex *GetAncestor(int height);
     const CBlockIndex *GetAncestor(int height) const;
 };
 
 /**
  * Maintain a map of CBlockIndex for all known headers.
  */
 struct BlockHasher {
     // this used to call `GetCheapHash()` in uint256, which was later moved; the
     // cheap hash function simply calls ReadLE64() however, so the end result is
     // identical
     size_t operator()(const BlockHash &hash) const {
         return ReadLE64(hash.begin());
     }
 };
 
 extern RecursiveMutex cs_main;
 typedef std::unordered_map<BlockHash, CBlockIndex *, BlockHasher> BlockMap;
 extern BlockMap &mapBlockIndex GUARDED_BY(cs_main);
 
 inline CBlockIndex *LookupBlockIndex(const BlockHash &hash)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
     BlockMap::const_iterator it = mapBlockIndex.find(hash);
     return it == mapBlockIndex.end() ? nullptr : it->second;
 }
 
 arith_uint256 GetBlockProof(const CBlockIndex &block);
 
 /**
  * Return the time it would take to redo the work difference between from and
  * to, assuming the current hashrate corresponds to the difficulty at tip, in
  * seconds.
  */
 int64_t GetBlockProofEquivalentTime(const CBlockIndex &to,
                                     const CBlockIndex &from,
                                     const CBlockIndex &tip,
                                     const Consensus::Params &);
 /**
  * Find the forking point between two chain tips.
  */
 const CBlockIndex *LastCommonAncestor(const CBlockIndex *pa,
                                       const CBlockIndex *pb);
 
 /**
  * Check if two block index are on the same fork.
  */
 bool AreOnTheSameFork(const CBlockIndex *pa, const CBlockIndex *pb);
 
 /** Used to marshal pointers into hashes for db storage. */
 class CDiskBlockIndex : public CBlockIndex {
 public:
     BlockHash hashPrev;
 
     CDiskBlockIndex() { hashPrev = BlockHash(); }
 
     explicit CDiskBlockIndex(const CBlockIndex *pindex) : CBlockIndex(*pindex) {
         hashPrev = (pprev ? pprev->GetBlockHash() : BlockHash());
     }
 
     ADD_SERIALIZE_METHODS;
 
     template <typename Stream, typename Operation>
     inline void SerializationOp(Stream &s, Operation ser_action) {
         int _nVersion = s.GetVersion();
         if (!(s.GetType() & SER_GETHASH)) {
             READWRITE(VARINT(_nVersion, VarIntMode::NONNEGATIVE_SIGNED));
         }
 
         READWRITE(VARINT(nHeight, VarIntMode::NONNEGATIVE_SIGNED));
         READWRITE(nStatus);
         READWRITE(VARINT(nTx));
         if (nStatus.hasData() || nStatus.hasUndo()) {
             READWRITE(VARINT(nFile, VarIntMode::NONNEGATIVE_SIGNED));
         }
         if (nStatus.hasData()) {
             READWRITE(VARINT(nDataPos));
         }
         if (nStatus.hasUndo()) {
             READWRITE(VARINT(nUndoPos));
         }
 
         // block header
         READWRITE(this->nVersion);
         READWRITE(hashPrev);
         READWRITE(hashMerkleRoot);
         READWRITE(nTime);
         READWRITE(nBits);
         READWRITE(nNonce);
     }
 
     BlockHash GetBlockHash() const {
         CBlockHeader block;
         block.nVersion = nVersion;
         block.hashPrevBlock = hashPrev;
         block.hashMerkleRoot = hashMerkleRoot;
         block.nTime = nTime;
         block.nBits = nBits;
         block.nNonce = nNonce;
         return block.GetHash();
     }
 
     std::string ToString() const {
         std::string str = "CDiskBlockIndex(";
         str += CBlockIndex::ToString();
         str += strprintf("\n                hashBlock=%s, hashPrev=%s)",
                          GetBlockHash().ToString(), hashPrev.ToString());
         return str;
     }
 };
 
 /**
  * An in-memory indexed chain of blocks.
  */
 class CChain {
 private:
     std::vector<CBlockIndex *> vChain;
 
 public:
     /**
      * Returns the index entry for the genesis block of this chain, or nullptr
      * if none.
      */
     CBlockIndex *Genesis() const {
         return vChain.size() > 0 ? vChain[0] : nullptr;
     }
 
     /**
      * Returns the index entry for the tip of this chain, or nullptr if none.
      */
     CBlockIndex *Tip() const {
         return vChain.size() > 0 ? vChain[vChain.size() - 1] : nullptr;
     }
 
     /**
      * Returns the index entry at a particular height in this chain, or nullptr
      * if no such height exists.
      */
     CBlockIndex *operator[](int nHeight) const {
         if (nHeight < 0 || nHeight >= (int)vChain.size()) {
             return nullptr;
         }
         return vChain[nHeight];
     }
 
     /** Compare two chains efficiently. */
     friend bool operator==(const CChain &a, const CChain &b) {
         return a.vChain.size() == b.vChain.size() &&
                a.vChain[a.vChain.size() - 1] == b.vChain[b.vChain.size() - 1];
     }
 
     /** Efficiently check whether a block is present in this chain. */
     bool Contains(const CBlockIndex *pindex) const {
         return (*this)[pindex->nHeight] == pindex;
     }
 
     /**
      * Find the successor of a block in this chain, or nullptr if the given
      * index is not found or is the tip.
      */
     CBlockIndex *Next(const CBlockIndex *pindex) const {
         if (!Contains(pindex)) {
             return nullptr;
         }
 
         return (*this)[pindex->nHeight + 1];
     }
 
     /**
      * Return the maximal height in the chain. Is equal to chain.Tip() ?
      * chain.Tip()->nHeight : -1.
      */
     int Height() const { return vChain.size() - 1; }
 
     /** Set/initialize a chain with a given tip. */
     void SetTip(CBlockIndex *pindex);
 
     /**
      * Return a CBlockLocator that refers to a block in this chain (by default
      * the tip).
      */
     CBlockLocator GetLocator(const CBlockIndex *pindex = nullptr) const;
 
     /**
      * Find the last common block between this chain and a block index entry.
      */
     const CBlockIndex *FindFork(const CBlockIndex *pindex) const;
 
     /**
      * Find the earliest block with timestamp equal or greater than the given
      * time and height equal or greater than the given height.
      */
     CBlockIndex *FindEarliestAtLeast(int64_t nTime, int height) const;
 };
 
 #endif // BITCOIN_CHAIN_H