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
```
}, true
    );
    CAmount fee;
    int change_position;
    bool rbf = pwallet->m_signal_rbf;
    const UniValue &replaceable_arg = request.params[3]["replaceable"];
    if (!replaceable_arg.isNull()) {
        RPCTypeCheckArgument(replaceable_arg, UniValue::VBOOL);
        rbf = replaceable_arg.isTrue();
    }
    CMutableTransaction rawTx = ConstructTransaction(request.params[0], request.params[1], request.params[2], rbf);
    CCoinControl coin_control;
    
    
    coin_control.m_add_inputs = rawTx.vin.size() == 0;
    FundTransaction(pwallet, rawTx, fee, change_position, request.params[3], coin_control);
    
    PartiallySignedTransaction psbtx(rawTx);
    
    bool bip32derivs = request.params[4].isNull() ? true : request.params[4].get_bool();
    bool complete = true;
    const TransactionError err = pwallet->FillPSBT(psbtx, complete, 1, false, bip32derivs);
    if (err != TransactionError::OK) {
        throw JSONRPCTransactionError(err);
    }
    
    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
    ssTx << psbtx;
    UniValue result(UniValue::VOBJ);
    result.pushKV("psbt", EncodeBase64(ssTx.str()));