Three Dollar Quill

I've got bidirectional typing set up. Most things are still doing inference, though. Functionally, what I have is "functions require ascriptions, and one of the tests is broken because I messed up error reporting". The former is a step forward, I think, and the latter... I'm going to need to ponder hard how to fix this. (It's possible that I'll try switching some things from synthesizing to checking, but right now the only reason I could think of to do so is if it would somehow improve error reporting.)

I'll see what I come up with, but for now I'm going to take it easy.

Good night.