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();
    
    
    pwallet->BlockUntilSyncedToCurrentChain();
    LOCK(pwallet->cs_wallet);
    return ValueFromAmount(GetReceived(*pwallet, request.params,  true));
},
    };
}
static RPCHelpMan getbalance()
{
    return RPCHelpMan{"getbalance",
                "\nReturns the total available balance.\n"
                "The available balance is what the wallet considers currently spendable, and is\n"
                "thus affected by options which limit spendability such as -spendzeroconfchange.\n",
                {
                    {"dummy", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "Remains for backward compatibility. Must be excluded or set to \"*\"."},
                    {"minconf", RPCArg::Type::NUM,  "0", "Only include transactions confirmed at least this many times."},
                    {"include_watchonly", RPCArg::Type::BOOL,  "true for watch-only wallets, otherwise false", "Also include balance in watch-only addresses (see 'importaddress')"},
                    {"avoid_reuse", RPCArg::Type::BOOL,  "true", "(only available if avoid_reuse wallet flag is set) Do not include balance in dirty outputs; addresses are considered dirty if they have previously been used in a transaction."},
                },
                RPCResult{
                    RPCResult::Type::STR_AMOUNT, "amount", "The total amount in " + CURRENCY_UNIT + " received for this wallet."
                },
                RPCExamples{
            "\nThe total amount in the wallet with 0 or more confirmations\n"
            + HelpExampleCli("getbalance", "") +