> The following is supposed to be OK: somebody reads your GPLed code, learns abstract concepts from it, teaches it to me, I write code that uses the same algorithm. But it's not OK to abbreviate the process and reach the same result directly with Copilot.
The trouble is that this apparently is not what Copilot is always doing. If it had only "learned abstract concepts" from GPL'd (or any other form of copyright) code, then that would not be a problem, and of course that is kind-of what Copilot purports to be doing, supposedly learning the association between concepts described in comments and corresponding forms of implementation.
However, apparently Copilot is sometimes NOT generating it's own code based on the concepts it has learned, but is instead just regurgitating chunks of potentially copyright-protected code verbatim. It'd be interesting to know if it is doing this deliberately (to maintain the coherence of what it is generating) or not - I guess the more of something it has already copied exactly the more it is likely to continue copying since that is the best "predict next word" continuation. Of course while it would be interesting to learn more about the mechanics of Copilot, that doesn't change the legality, or not, of what it is doing, another aspect of which (although IANAL) is how much of the original work is being copied.
At the end of the day it shouldn't matter whether it's you or Copilot either learning from or copying someone else's code - exact same copyright protections apply.