In going through all of the package versions for the 4.2
release-notes, I came across this:

--------------
Name: Kernel-eem.501
Author: eem
Time: 25 September 2010, 7:55:34.708 pm
UUID: 5b55eae3-594b-4416-9d47-5a4ebaabb238
Ancestors: Kernel-ul.500

Add mirror primitives which can be used for accurate
execution simulation (a.k.a. debugging) of proxies.
---------------

One of the things that concerns Magma applications are instances of
its own proxies being sent as an argument to a primitive.  I'm able to
rectify most cases with a simple #yourself to the argument in the
_sender_ (unfortunately I cannot do it in the top of the primitive
method itself, which would be ideal).

It's an unfortunate piercing of the transparency and so this made me
wonder whether there isn't a more general solution to this problem to
handle all cases.

 - Chris