Marcel Taeumel uploaded a new version of Collections to project The Trunk:
http://source.squeak.org/trunk/Collections-mt.592.mcz

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

Name: Collections-mt.592
Author: mt
Time: 15 January 2015, 2:38:22.051 pm
UUID: 1514e0fd-0cb5-6642-b335-98ed754dad41
Ancestors: Collections-mt.591

Some nil checks replaced with #notNil because ProtoObject knows it and it is faster (about 15%)

=============== Diff against Collections-mt.591 ===============

Item was changed:
  ----- Method: Dictionary>>includesKey: (in category 'testing') -----
  includesKey: key 
  	"Answer whether the receiver has a key equal to the argument, key."
  	
+ 	 ^(array at: (self scanFor: key)) notNil!
- 	 ^(array at: (self scanFor: key)) ~~ nil "We could use #notNil here, but ProtoObject doesn't understand it."!

Item was changed:
  ----- Method: KeyedSet>>includesKey: (in category 'testing') -----
  includesKey: key
  
+ 	^ (array at: (self scanFor: key)) notNil!
- 	^ (array at: (self scanFor: key)) ~~ nil!