Things work fine provided the become is one-way and hashes are not copied.
 Simply change
        (self containOnlyOops: array1 and: array2) ifFalse: [^false]

in ObjectMemory>>become:with:twoWay:copyHash: to

(twoWayFlag or: [copyHashFlag])
ifTrue: [(self containOnlyOops: array1 and: array2) ifFalse: [^false]]
ifFalse: [(self containOnlyOops: array1) ifFalse: [^false]].

along with the obvious implementation of containOnlyOops:.
If so,
| foo bar |
foo := 1 at 2.
bar := { foo. foo }.
foo becomeForward: 0 copyHash: false.
{ foo. bar }
produces
#(0 #(0 0))

On Thu, Sep 18, 2008 at 9:09 AM, Rob Withers <reefedjib at yahoo.com> wrote:

>
> ----- Original Message ----- From: "Paolo Bonzini" <bonzini at gnu.org>
> To: "The general-purpose Squeak developers list" <
> squeak-dev at lists.squeakfoundation.org>
> Sent: Tuesday, September 16, 2008 3:59 PM
> Subject: [squeak-dev] Re: becomeForward: alternative
>
>
>
>  Rob Withers wrote:
>>
>>> I am trying to becomeForward with an object and a small integer.  This
>>> of course doesn't work.  Is there an alternative that would allow me to
>>> do this?
>>>
>>
>> There's actually no reason why the *destination* of a becomeForward:
>> cannot be a SmallInteger.  It's a VM bug in my opinion.
>>
>>
> Thanks, Paolo.
>
> I tried looking into this a bit and here is what I have found.  First off,
> this will only work with
>   #elementsForwardIdentityTo: anArrayWithSmallIntegers copyHash: false.
> It would not work to copy the source hash to a SmallInteger.
>
> Next is understanding forwarding blocks and the process of remapping
> objects using them.  There are three steps:
>   1) #prepareForwardingTableForBecoming:with:twoWay:  "create and init
> forwarding blocks, and install into original headers"
>   2) #mapPointersInObjectsFrom:to:  "point pointers to forwarded oop"
>   3) #restoreHeadersAfterForwardBecome: "restore original headers"
> The question seems to come down to the following.  Can forwarding blocks
> point to SmallIntegers?
>
> Rob
>
>  Paolo
>>
>>
>
>
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