Program.cs

using System;

namespace MutableStructPitfalls
{
    public struct DisposableValue : IDisposable
    {
        private bool _disposedYet;

        public void Dispose()
        {
            if (!_disposedYet)
            {
                Console.WriteLine("Disposing for first time");
                _disposedYet = true;
            }
            else
            {
                Console.WriteLine("Was already disposed");
            }
        }
    }

    class Program
    {
        static void CallDispose(IDisposable o)
        {
            o.Dispose();
        }

        static void Main(string[] args)
        {
            var dv = new DisposableValue();
            Console.WriteLine("Passing value variable:");
            CallDispose(dv);
            CallDispose(dv);
            CallDispose(dv);

            IDisposable id = dv;
            Console.WriteLine("Passing interface variable:");
            CallDispose(id);
            CallDispose(id);
            CallDispose(id);

            Console.WriteLine("Calling Dispose directly on value variable:");
            dv.Dispose();
            dv.Dispose();
            dv.Dispose();

            Console.WriteLine("Passing value variable:");
            CallDispose(dv);
            CallDispose(dv);
            CallDispose(dv);
        }
    }
}