[worldsayshi]

If you hire a programmer that has worked on said closed source and ask them to recreate that code in your GPL licensed program - at what point will that be considered infring on the original? Can you relicense code of you feed it through a programmer?

[zaarn]

A programmer is a living breathing human, a legal entity that can hold copyright and is capable of violating copyright.

An AI cannot hold copyright however and isn't capable of violating copyright (legal entities are, which an AI is not).