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 (pwallet->IsLocked()) {
        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
    }
}
WalletContext& EnsureWalletContext(const util::Ref& context)
{
    if (!context.Has<WalletContext>()) {
        throw JSONRPCError(RPC_INTERNAL_ERROR, "Wallet context not found");
    }
    return context.Get<WalletContext>();
}
LegacyScriptPubKeyMan& EnsureLegacyScriptPubKeyMan(CWallet& wallet, bool also_create)
{
    LegacyScriptPubKeyMan* spk_man = wallet.GetLegacyScriptPubKeyMan();
    if (!spk_man && also_create) {
        spk_man = wallet.GetOrCreateLegacyScriptPubKeyMan();
    }
    if (!spk_man) {
        throw JSONRPCError(RPC_WALLET_ERROR, "This type of wallet does not support this command");
    }
    return *spk_man;
}
static void WalletTxToJSON(interfaces::Chain& chain, const CWalletTx& wtx, UniValue& entry)