Don't be that naive. Just because the executable is called Pharo, it's still a Squeak VM. You can open a Squeak image with it.
Thank's Levente. I not thought about it :)
No I tried 32 bits squeak with "some" Pharo vm for MacOS Sierra.
Both squeak 5.1 and trunk 6 are crashed. And they are crashed also with my example at line with #completeStep:. (Pharo has different implementation I guess)