Interesting question - I’d like to know the answer too. However it seems to me the immediate problem could be solved by putting legsNumber under IBird and have Penguin implement both IFish and IBird with no fields under it.
(a penguin is a bird and not a fish in real life…)
Syntactically, that is correct. GraphQL spec allows that behavior.
But unfortunately, we haven’t yet handled this case in our implementation. Thanks for bringing this to our notice.
This is something that we’ll look into after the 20.11 release is done. I can’t give you an ETA for this right now. If other folks are running into this issue, please let us know.