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
```
{"change_address", UniValueType(UniValue::VSTR)},
                {"changePosition", UniValueType(UniValue::VNUM)},
                {"change_position", UniValueType(UniValue::VNUM)},
                {"change_type", UniValueType(UniValue::VSTR)},
                {"includeWatching", UniValueType(UniValue::VBOOL)},
                {"include_watching", UniValueType(UniValue::VBOOL)},
                {"inputs", UniValueType(UniValue::VARR)},
                {"lockUnspents", UniValueType(UniValue::VBOOL)},
                {"lock_unspents", UniValueType(UniValue::VBOOL)},
                {"locktime", UniValueType(UniValue::VNUM)},
                {"feeRate", UniValueType()}, 
                {"psbt", UniValueType(UniValue::VBOOL)},
                {"subtractFeeFromOutputs", UniValueType(UniValue::VARR)},
                {"subtract_fee_from_outputs", UniValueType(UniValue::VARR)},
                {"replaceable", UniValueType(UniValue::VBOOL)},
                {"conf_target", UniValueType(UniValue::VNUM)},
                {"estimate_mode", UniValueType(UniValue::VSTR)},
            },
            true, true);
        if (options.exists("add_inputs") ) {
            coinControl.m_add_inputs = options["add_inputs"].get_bool();
        }
        if (options.exists("changeAddress") || options.exists("change_address")) {
            const std::string change_address_str = (options.exists("change_address") ? options["change_address"] : options["changeAddress"]).get_str();
            CTxDestination dest = DecodeDestination(change_address_str);
            if (!IsValidDestination(dest)) {
                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Change address must be a valid bitcoin address");
            }
            coinControl.destChange = dest;
        }