Function recurses infinitely

CLion detects that the following function 'recurses infinitely'.

As far as I see, that's not the case as long as there are no reference cycles.

How will I get rid of this 'warning'?

This is on 2019.3

class recurse {
  using value_type = std::variant<recurse, std::string>;
  std::vector<value_type> values_;
 public:
  std::string to_string() { return to_string(values_); };
 private:
  std::string to_string(const std::vector<value_type>& values){
    return std::accumulate(values.cbegin(), values.cend(), std::string{}, [this](const value_type& v) {
      if (std::holds_alternative<recurse>(v)) {
        return to_string(std::get<recurse>(v).values_);
      } else {
        return std::get<std::string>(v);
      }
    });
  }
}