using System;

​

public class Program

{

    public static void Main()

    {

        var foo = new Foo();

        var bar = new Bar();

        Console.WriteLine(object.ReferenceEquals(foo, foo)); // false

        Console.WriteLine(object.ReferenceEquals(bar, bar)); // true

    }

​

    public struct Foo

    {

    }

    public class Bar

    {

    }   

}