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
```
EnsureWalletIsUnlocked(pwallet);
    int version = 0;
    if (!request.params[0].isNull()) {
        version = request.params[0].get_int();
    }
    bilingual_str error;
    std::vector<bilingual_str> warnings;
    if (!pwallet->UpgradeWallet(version, error, warnings)) {
        throw JSONRPCError(RPC_WALLET_ERROR, error.original);
    }
    UniValue obj(UniValue::VOBJ);
    if (!error.empty()) {
        obj.pushKV("error", error.original);
    }
    return obj;
},
    };
}
RPCHelpMan abortrescan();
RPCHelpMan dumpprivkey();
RPCHelpMan importprivkey();
RPCHelpMan importaddress();
RPCHelpMan importpubkey();
RPCHelpMan dumpwallet();
RPCHelpMan importwallet();
RPCHelpMan importprunedfunds();
RPCHelpMan removeprunedfunds();
RPCHelpMan importmulti();
RPCHelpMan importdescriptors();
Span<const CRPCCommand> GetWalletRPCCommands()