```
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)
```
if (tuple_arguments_valid && lit_right)
                {
                    if (isInt64OrUInt64FieldType(lit_right->value.getType())
                        && lit_right->value.get<Int64>() >= 0)
                    {
                        if (frame.need_parens)
                            settings.ostr << '(';
                        arguments->children[0]->formatImpl(settings, state, nested_need_parens);
                        settings.ostr << (settings.hilite ? hilite_operator : "") << "." << (settings.hilite ? hilite_none : "");
                        arguments->children[1]->formatImpl(settings, state, nested_dont_need_parens);
                        written = true;
                        if (frame.need_parens)
                            settings.ostr << ')';
                    }
                }
            }
            if (!written && 0 == strcmp(name.c_str(), "lambda"))
            {
                
                if (frame.need_parens)
                    settings.ostr << '(';
                const auto * first_arg_func = arguments->children[0]->as<ASTFunction>();
                if (first_arg_func
                    && first_arg_func->name == "tuple"
                    && first_arg_func->arguments
                    && first_arg_func->arguments->children.size() == 1)
                {
                    first_arg_func->arguments->children[0]->formatImpl(settings, state, nested_need_parens);
                }
                else