using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var mut = new MutableRecord();

        mut.Foo = 2;

        var immut = new ImmutableRecord(1);

        // immut.Foo = 3; // Error

        var immutStruct = new ImmutableRecordStruct(1);

        // immutStruct.Foo = 3; // Error

    }

}

​

public record MutableRecord {

    public int Foo;

}

​

public record ImmutableRecord(int Foo) {

}

public readonly record struct ImmutableRecordStruct(int Foo) {

}

​