Volunteer for implementation review for `unknown case`?

Hi, all. With SE-0192 on the cusp of approval (or so I hope), and in the spirit of my “require pre-commit review” proposal, I’m looking for someone who is already familiar with the compiler representation of the Swift AST to review the implementation of unknown (or whatever it ends up being called). This consists largely of a bunch of changes to the logic that computes exhaustivity for switch statements, nicknamed the “Space Engine”.

This logic was originally implemented by @codafi, and while I’ve asked him for a review as well, he’s a free open source contributor and can do what he wants. Additionally, he’s by far the one who’s put the most time into it, with me and @Xi_Ge being the Apple people who’ve learned the pieces we need to make changes. This definitely feels like information that should be less siloed, so I’d like to explain what’s there to someone and what I changed to implement unknown, and they can tell me if that makes sense or if the code doesn’t match what I say I’m doing. This would probably be something we do live rather than the usual asynchronous GitHub PR review.

For the purposes of a review I do think this needs to be someone who’s already contributed to the compiler or SourceKit, though both Apple and non-Apple people can work. Any volunteers?

(I’d love to also explain this to people in general, but that’s a separate thing.)