GC of delegates, what am I missing? (my delegate is not collected)

Question

I have a class that holds on to a delegate, in order to lazily evaluate something later.

Once I\'ve evaluated it, by calling the delegate, I clear out the reference

Answer 1

The "problem" is that the compiler is noticing that it can reuse a single delegate instance forever. It doesn't capture any context, not even the implicit this reference. So this:

void CreateTestData(out WeakReference wr, out Lazy l)
{
    Func f = () => 10;
    ...
}

Is turned into something like:

static Func hiddenDelegate;

static int HiddenMethod()
{
    return 10;
}

void CreateTestData(out WeakReference wr, out Lazy l)
{
    if (hiddenDelegate == null)
    {
        hiddenDelegate = HiddenMethod;
    }

    Func f = hiddenDelegate;
    ...
}

Look at the code in ildasm (or Reflector with no optimization turned on) to see exactly what's going on.