Tobias Pape uploaded a new version of Environments to project Squeak 4.5:
http://source.squeak.org/squeak45/Environments-topa.55.mcz

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

Name: Environments-topa.55
Author: topa
Time: 21 January 2015, 11:15:37.19 am
UUID: ac4cd9b0-1628-4881-a2c2-f6d1e1a6f089
Ancestors: Environments-topa.54

3rd attempt at class-rename fixes. 

This version 
 a) avoids #becomeForward:
 b) fixes method homes after rename
 c) moves the obsolete binding to undeclared but keeps it working.

Effectively, this is the outcome:
| p |
p := Object subclass: #A instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Unknown'.
p compile: 'foo ^ A new'.
" literals of #foo {#A=>A . #foo . #A=>A}"
p rename: #B.
" literals of #foo {#A=>B . #foo . #B=>B}"
p new foo class == p.

=============== Diff against Environments-topa.54 ===============

Item was changed:
  ----- Method: Environment>>renameClass:from:to: (in category 'classes and traits') -----
  renameClass: aClass from: oldName to: newName
  	"Rename the class, aClass, to have the title newName."
  
+ 	| oldBinding newBinding category |
- 	| binding category |
  	category := self organization categoryOfElement: oldName.
  	self organization classify: newName under: category suppressIfDefault: true.
  	self organization removeElement: oldName.
  	
+ 	oldBinding := self declarationOf: oldName.
- 	binding := self declarationOf: oldName.
  	declarations removeKey: oldName.
+ 	self binding: oldBinding removedFrom: self.
+ 	" re-route now undeclared oldBinding "
+ 	oldBinding value: aClass.
- 	self binding: binding removedFrom: self.
- 	undeclared removeKey: oldName.
  
+ 	newBinding := newName => aClass.
+ 	aClass updateMethodBindingsTo: newBinding.
+ 	declarations add: newBinding. 
+ 	self binding: newBinding addedTo: self.
- 	binding becomeForward: (newName => aClass).
- 	declarations add: binding. 
- 	self binding: binding addedTo: self.
  	
  	Smalltalk renamedClass: aClass from: oldName to: newName.
  	SystemChangeNotifier uniqueInstance 
  		classRenamed: aClass 
  		from: oldName 
  		to: newName 
  		inCategory: category!