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
```
}
        }
        blockId = block.hashPrevBlock;
        --*altheight;
    }
    uint256 lastblock;
    target_confirms = std::min(target_confirms, wallet.GetLastBlockHeight() + 1);
    CHECK_NONFATAL(wallet.chain().findAncestorByHeight(wallet.GetLastBlockHash(), wallet.GetLastBlockHeight() + 1 - target_confirms, FoundBlock().hash(lastblock)));
    UniValue ret(UniValue::VOBJ);
    ret.pushKV("transactions", transactions);
    if (include_removed) ret.pushKV("removed", removed);
    ret.pushKV("lastblock", lastblock.GetHex());
    return ret;
},
    };
}
static RPCHelpMan gettransaction()
{
    return RPCHelpMan{"gettransaction",
                "\nGet detailed information about in-wallet transaction <txid>\n",
                {
                    {"txid", RPCArg::Type::STR, RPCArg::Optional::NO, "The transaction id"},
                    {"include_watchonly", RPCArg::Type::BOOL,  "true for watch-only wallets, otherwise false",
                            "Whether to include watch-only addresses in balance calculation and details[]"},
                    {"verbose", RPCArg::Type::BOOL,  "false",
                            "Whether to include a `decoded` field containing the decoded transaction (equivalent to RPC decoderawtransaction)"},
                },
                RPCResult{
                    RPCResult::Type::OBJ, "", "", Cat(Cat<std::vector<RPCResult>>(
                    {