Have this warning while building current master (0bd4929cd00e91bf4137f43b097cd62f72f503e4) on one test machine.
```
wallet/rpcwallet.cpp: In function 'rescanblockchain()::<lambda(const RPCHelpMan&, const JSONRPCRequest&)>':
wallet/rpcwallet.cpp:3596:19: warning: '*((void*)& stop_height +4)' may be used uninitialized in this function [-Wmaybe-uninitialized]
 3596 |     Optional<int> stop_height;
      |                   ^~~~~~~~~~~
```
```
$ gcc --version
gcc (Gentoo 9.2.0-r2 p3) 9.2.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ uname -a
Linux red-box 4.19.72-gentoo #2 SMP Sun Sep 22 03:00:01 EEST 2019 x86_64 Intel(R) Pentium(R) CPU N3710 @ 1.60GHz GenuineIntel GNU/Linux
```
const CWalletTx& wtx = it->second;
    CAmount nCredit = wtx.GetCredit(filter);
    CAmount nDebit = wtx.GetDebit(filter);
    CAmount nNet = nCredit - nDebit;
    CAmount nFee = (wtx.IsFromMe(filter) ? wtx.tx->GetValueOut() - nDebit : 0);
    entry.pushKV("amount", ValueFromAmount(nNet - nFee));
    if (wtx.IsFromMe(filter))
        entry.pushKV("fee", ValueFromAmount(nFee));
    WalletTxToJSON(pwallet->chain(), wtx, entry);
    UniValue details(UniValue::VARR);
    ListTransactions(pwallet, wtx, 0, false, details, filter, nullptr );
    entry.pushKV("details", details);
    std::string strHex = EncodeHexTx(*wtx.tx, pwallet->chain().rpcSerializationFlags());
    entry.pushKV("hex", strHex);
    if (verbose) {
        UniValue decoded(UniValue::VOBJ);
        TxToUniv(*wtx.tx, uint256(), decoded, false);
        entry.pushKV("decoded", decoded);
    }
    return entry;
},
    };
}
static RPCHelpMan abandontransaction()
{
    return RPCHelpMan{"abandontransaction",
                "\nMark in-wallet transaction <txid> as abandoned\n"
                "This will mark this transaction and all its in-wallet descendants as abandoned which will allow\n"
                "for their inputs to be respent.  It can be used to replace \"stuck\" or evicted transactions.\n"
                "It only works on transactions which are not included in a block and are not currently in the mempool.\n"