I'm having trouble understanding what happens when a ToArray() is called on an IEnumerable. I've always assumed that only the references are copied.

I would expect the output here to be: true true

But instead I get true false

What is going on here?

class One {
    public bool Foo { get; set; }
}

class Two
{
    public bool Foo { get; set; }
}

void Main()
{
    var collection1 = new[] { new One(), new One() };

    IEnumerable<Two> stuff = Convert(collection1);

    var firstOne = stuff.First();

    firstOne.Foo = true;

    Console.WriteLine (firstOne.Foo);

    var array = stuff.ToArray();

    Console.WriteLine (array[0].Foo);
}

IEnumerable<Two> Convert(IEnumerable<One> col1) {

    return
        from c in col1
        select new Two() {
            Foo = c.Foo
        };
}