On 3/31/2010 8:13 AM, Bert Freudenberg wrote:
> Show me a single place that would break in a real-world use-case.
>
> In fact, #become: is rarely used in Squeak because of its inherent slowness caused by our direct-pointer object model. And those rare places I can think of would work just fine.

I think there is one, and only one, place where #become: is 
intrinsically required: Changing class shape.

Cheers,
   - Andreas