using System;

using System.Text.Json;

​

public class Program

{

    public static void Main()

    {

        var parent = new Parent(new Child("arf"));

        Console.WriteLine(JsonSerializer.Serialize(parent));

        var newParent = new NewParent(new NewChild(0));

        Console.WriteLine(JsonSerializer.Serialize(newParent));

    }

}

​

public record Parent(Child Child);

public record Child(string String);

​

public record NewParent() : Parent(new Child("arf"))

{

    public NewParent(NewChild Child) : this()

    {

        this.Child = Child;

    }

    public new NewChild Child {get;set;}

}

​

public record NewChild(int Int);