#include <iostream>
#include "nlohmann/json.hpp"

using json = nlohmann::ordered_json;

// Minimum example of the bug
struct Base
{
  int b{};

  Base(int b) : b(b) {};
};

struct Derived : public Base
{
  int d{};

  Derived(int b, int d) : Base(b), d(d) {};
};

struct Container
{
  int a{};
  std::vector<std::shared_ptr<Base>> v{};

  Container(int a, std::vector<std::shared_ptr<Base>> v) : a(a), v(v) {};
};

void to_json(json& j, const std::shared_ptr<Base>& b)
{
  j = json{{"b", b->b}};
}

void to_json(json& j, const std::shared_ptr<Derived>& d)
{
  j = json{{"b", d->b}};
  j.update("d", d->d);
}

void to_json(json& j, const std::shared_ptr<Container>& c)
{
  j = json{ { "a", c->a } , { "data", c->v } };
}

void createOutputJson()
{
  json j;

  auto d1 = std::make_shared<Derived>(3, 4);
  auto d2 = std::make_shared<Derived>(5, 6);

  std::vector<std::shared_ptr<Base>> v2 = {d1, d2};

  auto C = std::make_shared<Container>(2, v2);

  j["Container"] = C;

  std::cout << j.dump(4) << std::endl;
}

int main() {
    createOutputJson();
}