From my PoV, pretending you can feed outputs, test suites or APIs from existing code and have AI "rewrite it" so you can call it your own is just theft. If instead you want to simply make it public domain, and this for some reason becomes acceptable, then it becomes the end of code as IP. The end of potentially any IP, which by the way I know plenty of people who would be happy about - "IP is theft" crowd - but which I think is unfair on those who had no real opportunity to build any equity on their work.
Precisely because I strongly believe in the potential of generative AI to eventually carry out entire projects with little technical guidance, I think it's important to establish the property of both what exists and what is achieved by humans with AI augmentation. This is a much more immediate concern than "runaway AI" or any form of singularity. As is today, generative AI has proven capable to replicate the results established projects with improvements (establishing how much is just parroted from the very replicated project and similar ones is academic in practice).