Hi -

I just noticed a subtle bug in Set>>fixCollisionsFrom: namely here:

[ (element := self keyAt: (index := index \\ array size + 1)) == nil ] 
whileFalse: [...].

The problem is that the usage of #keyAt: is incorrect here for Set 
subclasses (i.e., Dictionary). We don't want to stop when the *key* is 
nil (which can happen in Dictionaries) but rather when the *set entry* 
is nil. To illustrate the problem, here is the test that I just put into 
trunk:

testNilHashCollision
	"Ensures that fixCollisionsFrom: does the right thing in the presence 
of a nil key"
	| dict key |
	dict := Dictionary new.
	key := nil hash. "any key with same hash as nil"
	dict at: key put: 1.
	dict at: nil put: 2.
	self assert: (dict includesKey: nil).
	dict removeKey: key.
	self assert: (dict includesKey: nil).

I'm not sure if this is an old problem or got broken recently (there 
were various changes for faster sets etc).

Cheers,
   - Andreas