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
```
{
    UniValue ret(UniValue::VOBJ);
    if (verbose) {
        ret.pushKV("name", data.GetLabel());
    }
    ret.pushKV("purpose", data.purpose);
    return ret;
}
RPCHelpMan getaddressinfo()
{
    return RPCHelpMan{"getaddressinfo",
                "\nReturn information about the given bitcoin address.\n"
                "Some of the information will only be present if the address is in the active wallet.\n",
                {
                    {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The bitcoin address for which to get information."},
                },
                RPCResult{
                    RPCResult::Type::OBJ, "", "",
                    {
                        {RPCResult::Type::STR, "address", "The bitcoin address validated."},
                        {RPCResult::Type::STR_HEX, "scriptPubKey", "The hex-encoded scriptPubKey generated by the address."},
                        {RPCResult::Type::BOOL, "ismine", "If the address is yours."},
                        {RPCResult::Type::BOOL, "iswatchonly", "If the address is watchonly."},
                        {RPCResult::Type::BOOL, "solvable", "If we know how to spend coins sent to this address, ignoring the possible lack of private keys."},
                        {RPCResult::Type::STR, "desc",  true, "A descriptor for spending coins sent to this address (only when solvable)."},
                        {RPCResult::Type::BOOL, "isscript", "If the key is a script."},