A new version of Collections was added to project The Inbox:
http://source.squeak.org/inbox/Collections-cwp.470.mcz

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

Name: Collections-cwp.470
Author: cwp
Time: 20 July 2012, 11:57:39.778 am
UUID: ecae5676-1ea8-42a6-91f0-5c2c65045fec
Ancestors: Collections-dtl.469

Removed the requirement that ReadOnlyVariableBindings can only be used in Smalltalk globals. This makes it possible to create environments other than the root. (Necessary for EnvironmentTest, and eventually, multiple environments.)

=============== Diff against Collections-dtl.469 ===============

Item was changed:
  ----- Method: LookupKey>>beBindingOfType:announcing: (in category 'bindings') -----
  beBindingOfType: aClass announcing: aBool
  	"Make the receiver a global binding of the given type"
  
- 	(Smalltalk globals associationAt: self key) == self
- 		ifFalse:[^self error:'Not a global variable binding'].
  	self class == aClass ifTrue:[^self].
  	self becomeForward: (aClass key: self key value: self value).
  	"NOTE: Now self == read-only (e.g., the new binding)"
  	^self recompileBindingsAnnouncing: aBool!