How to handle the second level pointer properly?

[AlexLuya]

Hello,I have some code like this:

#include <vector>
#include <nlohmann/json.hpp>

struct In;
struct Item;

namespace nlohmann {

	template<>
	struct adl_serializer<std::vector<In*>> {
			static void to_json(json &j, const std::vector<In*> &ss) {

			}

			static void from_json(const json &j, std::vector<In*> &ss) {

			}
	};

	template<>
	struct adl_serializer<std::vector<Item*>> {
			static void to_json(json &j, const std::vector<Item*> &ss) {

			}

			static void from_json(const json &j, std::vector<Item*> &ss) {

			}
	};
}

struct Item{
		float x;
		float y;
		NLOHMANN_DEFINE_TYPE_INTRUSIVE(Item,x,y);
};

struct In {
		Item child;
		NLOHMANN_DEFINE_TYPE_INTRUSIVE(In,child);
};

struct Out {
		std::vector<In*> ins;
		NLOHMANN_DEFINE_TYPE_INTRUSIVE(Out,ins);
};

int main(){
	return 0;
};

As you can see,two levels pointer used here:
Out. std::vector<In*> ins -> In.Item* child;

These code will give compile error:

../src/C++Test.cpp:40:3: error: no viable overloaded '='
                NLOHMANN_DEFINE_TYPE_INTRUSIVE(In,child);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
....
/usr/local/include/nlohmann/json.hpp:19344:17: note: candidate function not viable: no known conversion from 'Item *const' to 'nlohmann::basic_json<>' for 1st argument
    basic_json& operator=(basic_json other) noexcept (
                ^
../src/C++Test.cpp:40:3: error: no matching member function for call to 'get_to'
                NLOHMANN_DEFINE_TYPE_INTRUSIVE(In,child);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/nlohmann/json.hpp:2495:132: note: expanded from macro 'NLOHMANN_DEFINE_TYPE_INTRUSIVE'
    friend void from_json(const nlohmann::json& nlohmann_json_j, Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_FROM, __VA_ARGS__)) }
                                                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/nlohmann/json.hpp:2420:31: note: expanded from macro 'NLOHMANN_JSON_PASTE'
        NLOHMANN_JSON_PASTE1)(__VA_ARGS__))
                              ^
/usr/local/include/nlohmann/json.hpp:2421:40: note: expanded from macro 'NLOHMANN_JSON_PASTE2'
#define NLOHMANN_JSON_PASTE2(func, v1) func(v1)
                                       ^
/usr/local/include/nlohmann/json.hpp:2486:56: note: expanded from macro 'NLOHMANN_JSON_FROM'
#define NLOHMANN_JSON_FROM(v1) nlohmann_json_j.at(#v1).get_to(nlohmann_json_t.v1);
                                                       ^
/usr/local/include/nlohmann/json.hpp:2354:35: note: expanded from macro 'NLOHMANN_JSON_EXPAND'
#define NLOHMANN_JSON_EXPAND( x ) x
                                  ^
/usr/local/include/nlohmann/json.hpp:2354:35: note: expanded from macro 'NLOHMANN_JSON_EXPAND'
#define NLOHMANN_JSON_EXPAND( x ) x
                                  ^
/usr/local/include/nlohmann/json.hpp:20316:17: note: candidate template ignored: requirement 'detail::has_from_json<nlohmann::basic_json<std::map, std::vector, std::basic_string<char, std::char_traits<char>, std::allocator<char>>, bool, long, unsigned long, double, std::allocator, adl_serializer, std::vector<unsigned char, std::allocator<unsigned char>>>, Item *, void>::value' was not satisfied [with ValueType = Item *]
    ValueType & get_to(ValueType& v) const noexcept(noexcept(
                ^
/usr/local/include/nlohmann/json.hpp:20329:17: note: candidate template ignored: requirement 'detail::is_basic_json<Item *>::value' was not satisfied [with ValueType = Item *]
    ValueType & get_to(ValueType& v) const
                ^
/usr/local/include/nlohmann/json.hpp:20340:11: note: candidate template ignored: could not match 'T [N]' against 'Item *'
    Array get_to(T (&v)[N]) const // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-array

If changed
In.Item* child; to In.Item child;

Everything compiles fine,but I do need this "child" to be a pointer,would you please tell me how to solve this problem?

[nlohmann]

The library knows how to handle std::vector. Can you try to provide a serializer for Item *?