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
```
}
        CHECK_NONFATAL(pwallet->chain().findAncestorByHeight(pwallet->GetLastBlockHash(), start_height, FoundBlock().hash(start_block)));
    }
    CWallet::ScanResult result =
        pwallet->ScanForWalletTransactions(start_block, start_height, stop_height, reserver, true );
    switch (result.status) {
    case CWallet::ScanResult::SUCCESS:
        break;
    case CWallet::ScanResult::FAILURE:
        throw JSONRPCError(RPC_MISC_ERROR, "Rescan failed. Potentially corrupted data files.");
    case CWallet::ScanResult::USER_ABORT:
        throw JSONRPCError(RPC_MISC_ERROR, "Rescan aborted.");
        
    }
    UniValue response(UniValue::VOBJ);
    response.pushKV("start_height", start_height);
    response.pushKV("stop_height", result.last_scanned_height ? *result.last_scanned_height : UniValue());
    return response;
},
    };
}
class DescribeWalletAddressVisitor : public boost::static_visitor<UniValue>
{
public:
    const SigningProvider * const provider;
    void ProcessSubScript(const CScript& subscript, UniValue& obj) const
    {
        
        std::vector<std::vector<unsigned char>> solutions_data;
        TxoutType which_type = Solver(subscript, solutions_data);