IronPython and callback delegates with 'out' or 'ref' parameters -- the obvious way doesn't work

The actual how-to is given here.

The only on-line documentation I could find that mentioned this has a

TODO - Delegates with out/ref parameters

about halfway down.

So, experiment time. Build callback.dll containing (or the same with 'out'):

	namespace Callback
	{
	using System;
	public delegate IntPtr Hook(ref bool handled);
	public static class Callback
	{
	public static object[] MakeCallback(Hook callback)
	{
	bool handled = false;
	IntPtr handle = callback(ref handled);
	return new object[] { handle, handled };
	}
	}
	}

view raw gistfile1.cs hosted with ❤ by GitHub

and call it from IronPython 2.6:

	import clr
	clr.AddReferenceToFile('Callback.dll')
	from Callback import *
	from System import IntPtr
	def callback(x):
	x = True
	return IntPtr(42)
	test = Callback.MakeCallback(callback)
	print test

view raw gistfile1.py hosted with ❤ by GitHub

which yields

Array[object]((<System.IntPtr object at 0x000000000000002B [42]>, False))

In sum -- it fails silently; the direct return value is fine, but mutating the actually by-value parameter does nothing.

Replacing the bool with int, and using non-default values shows that the value of a ref parameter is passed in correctly, it just can't be passed out with direct assignment.