Is modifying a value type from within a using statement undefined behavior?

Question

This one\'s really an offshoot of this question, but I think it deserves its own answer.

According to section 15.13 of the ECMA-334 (on the using statement,

Answer 1

To sum it up

struct Mutable : IDisposable
{
    public int Field;
    public void SetField( int value ) { Field = value; }
    public void Dispose() { }
}


class Program

{
    protected static readonly Mutable xxx = new Mutable();

    static void Main( string[] args )
    {
        //not allowed by compiler
        //xxx.Field = 10;

        xxx.SetField( 10 );

        //prints out 0 !!!! <--- I do think that this is pretty bad
        System.Console.Out.WriteLine( xxx.Field );

        using ( var m = new Mutable() )
        {
            // This results in a compiler error.
            //m.Field = 10;
            m.SetField( 10 );

            //This prints out 10 !!!
            System.Console.Out.WriteLine( m.Field );
        }



        System.Console.In.ReadLine();
    }

So in contrast to what I wrote above, I would recommend to NOT use a function to modify a struct within a using block. This seems wo work, but may stop to work in the future.

Mario