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
```
{
    return RPCHelpMan{"getreceivedbyaddress",
                "\nReturns the total amount received by the given address in transactions with at least minconf confirmations.\n",
                {
                    {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The bitcoin address for transactions."},
                    {"minconf", RPCArg::Type::NUM,  "1", "Only include transactions confirmed at least this many times."},
                },
                RPCResult{
                    RPCResult::Type::STR_AMOUNT, "amount", "The total amount in " + CURRENCY_UNIT + " received at this address."
                },
                RPCExamples{
            "\nThe amount from transactions with at least 1 confirmation\n"
            + HelpExampleCli("getreceivedbyaddress", "\"" + EXAMPLE_ADDRESS[0] + "\"") +
            "\nThe amount including unconfirmed transactions, zero confirmations\n"
            + HelpExampleCli("getreceivedbyaddress", "\"" + EXAMPLE_ADDRESS[0] + "\" 0") +
            "\nThe amount with at least 6 confirmations\n"
            + HelpExampleCli("getreceivedbyaddress", "\"" + EXAMPLE_ADDRESS[0] + "\" 6") +
            "\nAs a JSON-RPC call\n"
            + HelpExampleRpc("getreceivedbyaddress", "\"" + EXAMPLE_ADDRESS[0] + "\", 6")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    if (!wallet) return NullUniValue;
    const CWallet* const pwallet = wallet.get();