`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.
{
        tx = txIn; i = iIn; nDepth = nDepthIn; fSpendable = fSpendableIn; fSolvable = fSolvableIn; fSafe = fSafeIn; nInputBytes = -1; use_max_sig = use_max_sig_in;
        
        
        if (fSpendable && tx) {
            nInputBytes = tx->GetSpendSize(i, use_max_sig);
        }
    }
    std::string ToString() const;
    inline CInputCoin GetInputCoin() const
    {
        return CInputCoin(tx->tx, i, nInputBytes);
    }
};
class CWalletKey
{
public:
    CPrivKey vchPrivKey;
    int64_t nTimeCreated;
    int64_t nTimeExpires;
    std::string strComment;
    
    
    explicit CWalletKey(int64_t nExpires=0);
    ADD_SERIALIZE_METHODS;
    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {