`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.
{
        nAmount = 0;
        nConf = std::numeric_limits<int>::max();
        fIsWatchonly = false;
    }
};
static UniValue ListReceived(interfaces::Chain::Lock& locked_chain, CWallet * const pwallet, const UniValue& params, bool by_label) EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)
{
    LockAnnotation lock(::cs_main); 
    
    int nMinDepth = 1;
    if (!params[0].isNull())
        nMinDepth = params[0].get_int();
    
    bool fIncludeEmpty = false;
    if (!params[1].isNull())
        fIncludeEmpty = params[1].get_bool();
    isminefilter filter = ISMINE_SPENDABLE;
    if(!params[2].isNull())
        if(params[2].get_bool())
            filter = filter | ISMINE_WATCH_ONLY;
    bool has_filtered_address = false;
    CTxDestination filtered_address = CNoDestination();
    if (!by_label && params.size() > 3) {
        if (!IsValidDestinationString(params[3].get_str())) {
            throw JSONRPCError(RPC_WALLET_ERROR, "address_filter parameter was invalid");
        }
        filtered_address = DecodeDestination(params[3].get_str());