I would think that to combine the models, the software would need some internal method to differentiate between the licenses used by the various code sources it's pulling it's suggestion "ideas" from, and the compatibility between the licenses of those sources and your own choice of licensing for the project you're creating.

eg, cleanliness described by different linters/static-analysis tools? Can we actually make better code suggestions by choosing examples which are known to have less super-obvious flaws?

There's certain information I cannot share, but you can see the general idea of what I'm throwing out here

I would imagine saying "Copyright (c) appropriate rights holders on planet Earth" wouldn't satisfy most license attribution claims if they were ever tested in court.