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 RPCHelpMan{"sendtoaddress",
                "\nSend an amount to a given address." +
        HELP_REQUIRING_PASSPHRASE,
                {
                    {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The bitcoin address to send to."},
                    {"amount", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "The amount in " + CURRENCY_UNIT + " to send. eg 0.1"},
                    {"comment", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "A comment used to store what the transaction is for.\n"
                                         "This is not part of the transaction, just kept in your wallet."},
                    {"comment_to", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "A comment to store the name of the person or organization\n"
                                         "to which you're sending the transaction. This is not part of the \n"
                                         "transaction, just kept in your wallet."},
                    {"subtractfeefromamount", RPCArg::Type::BOOL,  "false", "The fee will be deducted from the amount being sent.\n"
                                         "The recipient will receive less bitcoins than you enter in the amount field."},
                    {"replaceable", RPCArg::Type::BOOL,  "wallet default", "Allow this transaction to be replaced by a transaction with higher fees via BIP 125"},
                    {"conf_target", RPCArg::Type::NUM,  "wallet -txconfirmtarget", "Confirmation target (in blocks)\n"
                                         "or fee rate (for " + CURRENCY_UNIT + "/kB and " + CURRENCY_ATOM + "/B estimate modes)"},
                    {"estimate_mode", RPCArg::Type::STR,  "unset", std::string() + "The fee estimate mode, must be one of (case insensitive):\n"
            "       \"" + FeeModes("\"\n\"") + "\""},
                    {"avoid_reuse", RPCArg::Type::BOOL,  "true", "(only available if avoid_reuse wallet flag is set) Avoid spending from dirty addresses; addresses are considered\n"
                                         "dirty if they have previously been used in a transaction."},
                    {"verbose", RPCArg::Type::BOOL,  "false", "If true, return extra information about the transaction."},
                },
                {
                    RPCResult{"if verbose is not set or set to false",
                        RPCResult::Type::STR_HEX, "txid", "The transaction id."