https://github.com/bitcoin/bitcoin/blob/9ad6f14175c19b5d47267c3dd5840c14bad43c83/src/validation.cpp#L3711

If i'm following right the flow of the code, when we hit this lane `pindex` should be always equal to nullptr thus this check may be omitted
}
            if (coin.nHeight == MEMPOOL_HEIGHT) {
                
                prevheights[txinIndex] = tip->nHeight + 1;
            } else {
                prevheights[txinIndex] = coin.nHeight;
            }
        }
        lockPair = CalculateSequenceLocks(tx, flags, prevheights, index);
        if (lp) {
            lp->height = lockPair.first;
            lp->time = lockPair.second;
            
            
            
            
            
            
            
            
            
            
            
            
            
            int maxInputHeight = 0;
            for (const int height : prevheights) {
                
                if (height != tip->nHeight+1) {
                    maxInputHeight = std::max(maxInputHeight, height);