If someone else uses your exact same prompt to generate the exact same code, can you claim copyright infringement against them? If the output is possible to copyright, then you could claim their prompt is infringement (just like if it reproduced Harry Potter). If it isn’t copyrightable, then the kernel would not have legal standing to enforce the GPL on those lines of code against any future AI reproduction of them. The developers might need to show that the code is licensed under GPL and only GPL, otherwise there is the possibility the same original contributor (eg the AI) did permit the copy. The GPL is an imposed restriction on what the kernel can legally do with any code contributions. That seems legally complicated for some projects—probably not the kernel with the large amount of pre-AI code, but maybe it spells trouble for smaller newer projects if they want to sue over infringement. IANAL.
Copyright infringement is triggered by the act of copying, not by having the same bytes.
> If someone else uses your exact same prompt to generate the exact same code, can you claim copyright infringement against them?
No, because they've independently obtained it from the same source that you did, so their copy is "upstream" of your imposing of a new license.
Realistically, adding a license to public domain work is only really meaningful when you've used it as a starting point for something else, and want to apply your license to the derivative work.