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
```
{
    return{{RPCResult::Type::NUM, "confirmations", "The number of confirmations for the transaction. Negative confirmations means the\n"
               "transaction conflicted that many blocks ago."},
           {RPCResult::Type::BOOL, "generated", "Only present if transaction only input is a coinbase one."},
           {RPCResult::Type::BOOL, "trusted", "Only present if we consider transaction to be trusted and so safe to spend from."},
           {RPCResult::Type::STR_HEX, "blockhash", "The block hash containing the transaction."},
           {RPCResult::Type::NUM, "blockheight", "The block height containing the transaction."},
           {RPCResult::Type::NUM, "blockindex", "The index of the transaction in the block that includes it."},
           {RPCResult::Type::NUM_TIME, "blocktime", "The block time expressed in " + UNIX_EPOCH_TIME + "."},
           {RPCResult::Type::STR_HEX, "txid", "The transaction id."},
           {RPCResult::Type::ARR, "walletconflicts", "Conflicting transaction ids.",
           {
               {RPCResult::Type::STR_HEX, "txid", "The transaction id."},
           }},
           {RPCResult::Type::NUM_TIME, "time", "The transaction time expressed in " + UNIX_EPOCH_TIME + "."},
           {RPCResult::Type::NUM_TIME, "timereceived", "The time received expressed in " + UNIX_EPOCH_TIME + "."},
           {RPCResult::Type::STR, "comment", "If a comment is associated with the transaction, only present if not empty."},
           {RPCResult::Type::STR, "bip125-replaceable", "(\"yes|no|unknown\") Whether this transaction could be replaced due to BIP125 (replace-by-fee);\n"
               "may be unknown for unconfirmed transactions not in the mempool"}};
}
static RPCHelpMan listtransactions()