ContextualCheckBlockHeader should never have pindexPrev to NULL

src/validation.cpp

@@ -2973,7 +2973,8 @@ std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBloc
 
 bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev, int64_t nAdjustedTime)
 {
-    const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;
+    assert(pindexPrev != NULL);
+    const int nHeight = pindexPrev->nHeight + 1;
     // Check proof of work
     if (block.nBits != GetNextWorkRequired(pindexPrev, &block, consensusParams))
         return state.DoS(100, false, REJECT_INVALID, "bad-diffbits", false, "incorrect proof of work");