Indeed, I guess Venusian will get confused, but not sure thats solvable as there will be obvious bugs indicating that call shouldn't be imported at module-level.

This does feel like the problem is actually with inspect.unwrap: there's evidence of an attempt to catch infinite loops like this and blow up with a ValueError, it just doesn't appear those checks are good enough. How many levels of unwrapping are reasonable? 1? 5? 100? It feels like the loop detection should be count, not set-of-ids based...

The other optional we be for _Call instances to be generative only in the right context, or only to a certain depth (10? how deep can one set of calls realistically be?)

I suspect both should probably happen... Thoughts?