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
```
const TransactionError err = pwallet->FillPSBT(psbtx, complete, SIGHASH_ALL, true, false);
            if (err != TransactionError::OK) {
                throw JSONRPCTransactionError(err);
            }
            CMutableTransaction mtx;
            complete = FinalizeAndExtractPSBT(psbtx, mtx);
            UniValue result(UniValue::VOBJ);
            if (psbt_opt_in || !complete || !add_to_wallet) {
                
                CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
                ssTx << psbtx;
                result.pushKV("psbt", EncodeBase64(ssTx.str()));
            }
            if (complete) {
                std::string err_string;
                std::string hex = EncodeHexTx(CTransaction(mtx));
                CTransactionRef tx(MakeTransactionRef(std::move(mtx)));
                result.pushKV("txid", tx->GetHash().GetHex());
                if (add_to_wallet && !psbt_opt_in) {
                    pwallet->CommitTransaction(tx, {}, {} );
                } else {
                    result.pushKV("hex", hex);
                }
            }
            result.pushKV("complete", complete);
            return result;
        }
    };
}
static RPCHelpMan sethdseed()