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
```
{
    if (!estimate_mode.isNull()) {
        if (!FeeModeFromString(estimate_mode.get_str(), cc.m_fee_mode)) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid estimate_mode parameter");
        }
    }
    if (cc.m_fee_mode == FeeEstimateMode::BTC_KB || cc.m_fee_mode == FeeEstimateMode::SAT_B) {
        if (estimate_param.isNull()) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Selected estimate_mode %s requires a fee rate to be specified in conf_target", estimate_mode.get_str()));
        }
        CAmount fee_rate = AmountFromValue(estimate_param);
        if (cc.m_fee_mode == FeeEstimateMode::SAT_B) {
            fee_rate /= WALLET_BTC_KB_TO_SAT_B;
        }
        cc.m_feerate = CFeeRate(fee_rate);
        
        if (cc.m_signal_bip125_rbf == nullopt) cc.m_signal_bip125_rbf = true;
    } else if (!estimate_param.isNull()) {
        cc.m_confirm_target = ParseConfirmTarget(estimate_param, pwallet->chain().estimateMaxBlocks());
    }
}
static RPCHelpMan getnewaddress()