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 (involvesWatchonly || (pwallet->IsMine(s.destination) & ISMINE_WATCH_ONLY)) {
                entry.pushKV("involvesWatchonly", true);
            }
            MaybePushAddress(entry, s.destination);
            entry.pushKV("category", "send");
            entry.pushKV("amount", ValueFromAmount(-s.amount));
            const auto* address_book_entry = pwallet->FindAddressBookEntry(s.destination);
            if (address_book_entry) {
                entry.pushKV("label", address_book_entry->GetLabel());
            }
            entry.pushKV("vout", s.vout);
            entry.pushKV("fee", ValueFromAmount(-nFee));
            if (fLong)
                WalletTxToJSON(pwallet->chain(), wtx, entry);
            entry.pushKV("abandoned", wtx.isAbandoned());
            ret.push_back(entry);
        }
    }
    
    if (listReceived.size() > 0 && wtx.GetDepthInMainChain() >= nMinDepth) {
        for (const COutputEntry& r : listReceived)
        {
            std::string label;
            const auto* address_book_entry = pwallet->FindAddressBookEntry(r.destination);
            if (address_book_entry) {
                label = address_book_entry->GetLabel();
            }
            if (filter_label && label != *filter_label) {
                continue;
            }