Chris Muller uploaded a new version of Collections to project The Trunk:
http://source.squeak.org/trunk/Collections-cmm.474.mcz

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

Name: Collections-cmm.474
Author: cmm
Time: 30 April 2012, 7:48:33.662 pm
UUID: 7b4f3b2a-8b18-4430-8a9b-b3f505b041ed
Ancestors: Collections-cmm.471, Collections-eem.473

Merged cmm.471 to allow, but not require, the system to support concatenation semantics.

=============== Diff against Collections-eem.473 ===============

Item was changed:
  ----- Method: Collection>>, (in category 'copying') -----
  , aCollection
+ 
+ 	^ self copy addAll: aCollection asCollection; yourself!
- 	^self copy addAll: aCollection; yourself!

Item was added:
+ ----- Method: Collection>>asCollection (in category 'converting') -----
+ asCollection
+ 
+ 	^ self!

Item was changed:
  ----- Method: SequenceableCollection>>, (in category 'copying') -----
  , otherCollection 
  	"Concatenate two Strings or Collections."
- 	
  	^ self copyReplaceFrom: self size + 1
  		  to: self size
+ 		  with: otherCollection asCollection
- 		  with: otherCollection
  "
  #(2 4 6 8) , #(who do we appreciate)
  ((2989 storeStringBase: 16) copyFrom: 4 to: 6) , ' boy!!'
  "!