// Test from http://joeduffyblog.com/2010/07/01/when-is-a-readonly-field-not-readonly/

public class Program

{

    struct S {

        public readonly int X;

        public S(int x) { X = x; }

        public void MultiplyInto(int c, out S target) {

            System.Console.WriteLine(this.X);

            target = new S(X * c);

            System.Console.WriteLine(this.X); // same? it is, after all, readonly.

    }

}

​

​

    public static void Main()

    {

        S s = new S(42);

        s.MultiplyInto(10, out s);

    }

}