Ensue and isinstance() #280
Description
Ensue should probably use a protocol instead of an instance check. I'm not sure how best to do that. Ensues from preludes from different files or even from the same file after a reload are not currently compatible, and they probably should be. I can't think of an example of this ever coming up though. Maybe the prelude should do something like deftypeonce to prevent the reload issue? That still won't help if they're defined in multiple files. I need to think about this more.