Tobias Pape uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-topa.833.mcz

==================== Summary ====================

Name: Kernel-topa.833
Author: topa
Time: 25 January 2014, 11:44:53.514 pm
UUID: c75fce66-1af9-446c-b847-e9be57bd79ea
Ancestors: Kernel-cwp.832

Allow for Traits to be _not_ present when obsoleting a Class.
Necessary to actually be able to unload Traits in the first place.

=============== Diff against Kernel-cwp.832 ===============

Item was changed:
  ----- Method: ClassDescription>>obsolete (in category 'initialize-release') -----
  obsolete
  	"Make the receiver obsolete."
+ 	(self respondsTo: #hasTraitComposition) ifTrue: [
+ 		self hasTraitComposition ifTrue: [
+ 			self traitComposition do: [:each |
+ 				each removeTraitUser: self]]].
- 	self hasTraitComposition ifTrue: [
- 		self traitComposition do: [:each |
- 			each removeTraitUser: self]].
  	superclass removeSubclass: self.
  	self organization: nil.
  	super obsolete.!