#nullable enable

using System;

using System.Collections.Generic;

public class Program

{

    public class Foo : IEquatable<Foo>

    {

        public string Fizz { get; set; } = default!;

        public string Fuzz { get; set; } = default!;

        public bool Equals(Foo? other) => other != null && (Fizz, Fuzz) == (other.Fizz, other.Fuzz);

        public override bool Equals(object? obj) => Equals(obj as Foo);

​

        public override int GetHashCode() => HashCode.Combine(Fizz, Fuzz);

    }

    public record class Bar 

    {

        public string Fizz { get; set; } = default!;

        public string Fuzz { get; set; } = default!;

    }

    public static void Main()

    {

        var a = new Foo { Fizz = "Fizz", Fuzz = "Fuzz" };

        var b = new Foo { Fizz = "Fizz", Fuzz = "Fuzz" };

        var c = a.Equals(b);

        var d = a == b;

        var e = c == d;

        var f = new Bar { Fizz = "Fizz", Fuzz = "Fuzz" };

        var g = new Bar { Fizz = "Fizz", Fuzz = "Fuzz" };

        var h = f.Equals(g);

        var i = f == g;

        var j = h == i;

        Console.WriteLine(e);

        Console.WriteLine(j);

    }

}