using System;

using System.Diagnostics;

​

class C 

{ 

    public int x;

}

public class Program

{

    public static void Main()

    {

        var a = new C();

        a.x = 42;

        var b = new C();

        b.x = 42;

        var c = a;

        Debug.Assert(a == a);

        Debug.Assert(b != a);

        Debug.Assert(a != b);

        Debug.Assert(a == c);

        Debug.Assert(c == a);

        Debug.Assert(b != c);

        Debug.Assert(c != b);

        // Compilation error (line 17, col 16): Operator '<' cannot be applied to operands of type 'C' and 'C'

        // Debug.Assert(a < b);

    }

}