```
2021.10.22 07:14:33.963099 [ 3451059 ] {} <Error> Application: DB::Exception: Syntax error (in file ./user_defined/function_a_function.sql): failed at position 39 ('->'): -> ch(2)

$ cat ./user_defined/function_a_function.sql
CREATE FUNCTION a_function AS tuple() -> ch(2)
```
{
                "isNull",          " IS NULL",
                "isNotNull",       " IS NOT NULL",
                nullptr
            };
            for (const char ** func = operators; *func; func += 2)
            {
                if (strcasecmp(name.c_str(), func[0]) != 0)
                {
                    continue;
                }
                arguments->formatImpl(settings, state, nested_need_parens);
                settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
                written = true;
                break;
            }
        }
        /** need_parens - do we need parentheses around the expression with the operator.
          * They are needed only if this expression is included in another expression with the operator.
          */
        if (!written && arguments->children.size() == 2)
        {
            const char * operators[] =
            {
                "multiply",        " * ",
                "divide",          " / ",
                "modulo",          " % ",
                "plus",            " + ",
                "minus",           " - ",
                "notEquals",       " != ",