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
```
{
    EnsureWalletIsUnlocked(pwallet);
    
    std::shuffle(recipients.begin(), recipients.end(), FastRandomContext());
    
    CAmount nFeeRequired = 0;
    int nChangePosRet = -1;
    bilingual_str error;
    CTransactionRef tx;
    FeeCalculation fee_calc_out;
    bool fCreated = pwallet->CreateTransaction(recipients, tx, nFeeRequired, nChangePosRet, error, coin_control, fee_calc_out, !pwallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS));
    if (!fCreated) {
        throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, error.original);
    }
    pwallet->CommitTransaction(tx, std::move(map_value), {} );
    if (verbose) {
        UniValue entry(UniValue::VOBJ);
        entry.pushKV("txid", tx->GetHash().GetHex());
        entry.pushKV("fee_reason", StringForFeeReason(fee_calc_out.reason));
        return entry;
    }
    return tx->GetHash().GetHex();
}
static RPCHelpMan sendtoaddress()