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
```
std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    if (!wallet) return NullUniValue;
    const CWallet* const pwallet = wallet.get();
    RPCTypeCheck(request.params, {UniValue::VSTR, UniValue::VARR, UniValue::VSTR}, true);
    CMutableTransaction mtx;
    if (!DecodeHexTx(mtx, request.params[0].get_str())) {
        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed. Make sure the tx has at least one input.");
    }
    
    LOCK(pwallet->cs_wallet);
    EnsureWalletIsUnlocked(pwallet);
    
    std::map<COutPoint, Coin> coins;
    for (const CTxIn& txin : mtx.vin) {
        coins[txin.prevout]; 
    }
    pwallet->chain().findCoins(coins);
    
    ParsePrevouts(request.params[1], nullptr, coins);
    int nHashType = ParseSighashString(request.params[2]);
    
    std::map<int, std::string> input_errors;
    bool complete = pwallet->SignTransaction(mtx, coins, nHashType, input_errors);
    UniValue result(UniValue::VOBJ);
    SignTransactionResultToJSON(mtx, complete, coins, input_errors, result);
    return result;
},
    };
}
static RPCHelpMan bumpfee_helper(std::string method_name)