```
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)
```
const auto * function = arguments->children[0]->as<ASTFunction>();
                bool negate = name == "negate";
                bool is_tuple = literal && literal->value.getType() == Field::Types::Tuple;
                
                bool literal_need_parens = literal && !is_tuple;
                
                bool negate_need_parens = negate && (literal_need_parens || (function && function->name == "negate"));
                
                bool need_parens = !literal && frame.need_parens && !negate_need_parens;
                
                if (negate_need_parens)
                    nested_need_parens.need_parens = false;
                if (need_parens)
                    settings.ostr << '(';
                settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
                if (negate_need_parens)
                    settings.ostr << '(';
                arguments->formatImpl(settings, state, nested_need_parens);
                written = true;
                if (negate_need_parens)
                    settings.ostr << ')';
                if (need_parens)
                    settings.ostr << ')';
                break;
            }
        }
        
        if (!written && arguments->children.size() == 1)
        {
            const char * operators[] =