`ScanForWalletTransactions()` has the following comment about its return value:

```
 * Returns null if scan was successful. Otherwise, if a complete rescan was not
 * possible (due to pruning or corruption), returns pointer to the most recent
 * block that could not be scanned.
```

This is not strictly true. If `abortrescan` is called, then `ScanForWalletTransactions()` will return `nullptr`, even though the scan wasn't successful to the tip.

This in turn causes a minor bug in `importmulti`, where the call doesn't return the correct error and warning about potentially not finding transactions if `abortrescan` was called.

I think the correct fix is for `ScanForWalletTransactions()` to inform the caller that the rescan was aborted.
{
    auto locked_chain = chain().lock();
    LOCK(cs_wallet);
    int conflictconfirms = 0;
    CBlockIndex* pindex = LookupBlockIndex(hashBlock);
    if (pindex && chainActive.Contains(pindex)) {
        conflictconfirms = -(chainActive.Height() - pindex->nHeight + 1);
    }
    
    
    
    
    if (conflictconfirms >= 0)
        return;
    
    WalletBatch batch(*database, "r+", false);
    std::set<uint256> todo;
    std::set<uint256> done;
    todo.insert(hashTx);