Hi Levente, the new structure of LRUCache seems to expose a problem
with chasing pointers.  When I try to chase pointers to any object,
one of the LRUCache's

I'm still digging to try and see whether its a bug with chasing
pointers or just a stack-depth limitation.  What I see so far is that
PointerFinder wants to ask whether the 'head' var of the new LRUCache
#isLiteral.  That is what leads to the VM crash.

    (LRUCache allInstances anyOne instVarNamed: 'head') isLiteral

I noticed the 'head' var is initialized as a two-element Array, with
each element being the array itself.  So trying to ask an Array
#isLiteral won't work in that case, e.g.,

     |a| a:=Array new: 1.
     a at: 1 put: a.
     a isLiteral

causes the same issue.

Clearly, we cannot release with a broke PointerFinder.  So, what's the
best fix folks?  My first reaction is a guard in Array>>#isLiteral?

     isLiteral
          ^ self class == Array and: [ (self includes: self) not and:
[ self allSatisfy: [ : each | each isLiteral ] ] ]

Thanks.