A new version of Collections was added to project The Inbox:
http://source.squeak.org/inbox/Collections-nice.423.mcz

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

Name: Collections-nice.423
Author: nice
Time: 30 September 2011, 10:12:20.333 pm
UUID: 7613573f-6d08-9d4c-9d9e-2eaacff799fe
Ancestors: Collections-ul.422

#size and #do: default implementation will cause an infinite loop in every new subclass of SequenceableCollection without any form of warning to the poor programmer.

It's simple to avoid this bad behavior by:
- moving Collection>>size implementation to the sole place where it is used (LinkedList)
- replacing it with a subclassResponsibility.

=============== Diff against Collections-ul.422 ===============

Item was changed:
  ----- Method: Collection>>size (in category 'accessing') -----
  size
  	"Answer how many elements the receiver contains."
  
+ 	^self subclassResponsibility!
- 	| tally |
- 	tally := 0.
- 	self do: [:each | tally := tally + 1].
- 	^ tally!

Item was added:
+ ----- Method: LinkedList>>size (in category 'accessing') -----
+ size
+ 	"Answer how many elements the receiver contains."
+ 
+ 	| tally |
+ 	tally := 0.
+ 	self do: [:each | tally := tally + 1].
+ 	^ tally!