My recent adventures led me to this code:
Set>>grow
	"Grow the elements array and reinsert the old elements"
	| oldElements |
	oldElements _ array.
	array _ Array new: array size + self growSize.
	tally _ 0.
	oldElements do:
		[:each | each == nil ifFalse: [self noCheckAdd: each]]

If another squeak thread (NOT native thread) interrupts this
operation, isn't there a possibility for bad things to happen?
This operation might be triggered any time an element is added to a
set.

A variation that constructed the new array first might be a bit safer,
but it could still have problems if something was added or removed
from the set in midstream.

Subclasses of Set seem to have similar issues.

I thought smalltalk was supposed to be thread-safe with respect to its
own threads.  Am I mistaken in that belief, or in my analysis that the
operation is not thread safe?

I'm aware that the solution would exact several kinds of penalties
(clarity, speed, memory).

Ross Boylan