That's not what Google v Oracle was about. That case was about whether the API of a piece of code (in this case, the API of most of the Java standard library) i

That's not what Google v Oracle was about. That case was about whether the API of a piece of code (in this case, the API of most of the Java standard library) is copyrightable as a whole, without the implementation; and subsequently, even if they are copyrightable, whether a new implementation of that API would be fair use. In the end the conclusion from the SC was that Google's use was fair use regardless of the question of copyrightability, which they didn't decide on (the previous court, at Oracle's appeal, had found that APIs are in fact copyrightable and that Google's use did not fall under fair use of that copyrighted API as they weren't 100% compatible with other JVMs).