inline void ReferenceChecker::visit(Reference &ope) {
  auto it = std::find(params_.begin(), params_.end(), ope.name_);
  if (it != params_.end()) { return; }

  if (!grammar_.count(ope.name_)) {
    error_s[ope.name_] = ope.s_;
    error_message[ope.name_] = "'" + ope.name_ + "' is not defined.";
  } else {
    const auto &rule = grammar_.at(ope.name_);
    if (rule.is_macro) {
      if (!ope.is_macro_ || ope.args_.size() != rule.params.size()) {
        error_s[ope.name_] = ope.s_;
        error_message[ope.name_] = "incorrect number of arguments.";
      }
    } else if (ope.is_macro_) {
      error_s[ope.name_] = ope.s_;
      error_message[ope.name_] = "'" + ope.name_ + "' is not macro.";
    }
  }
}
Unknown