Show HN: Flow for Lua (EmmyLua PR)

I'm the author of this PR.

If you're writing Lua and not already using EmmyLua, then I highly recommend you check it out. Basically the current release already has built-in support for basic type annotations, with limited support for static type checking.

The pull request linked basically significantly extends what kinds of types can be described, fixes some type checking bugs and adds some new static type-checking error reporting. It's still nowhere near as powerful as Flow, and not really intended to be. However, the premise is roughly the same.

P.S. To anyone looking at this pull request for inspiration, don't. This is a pretty terrible way to submit a pull request. It's enormous and only very roughly delineated into feature commits, with many future commits fixing bugs in earlier commits. It's basically a result of several months of on-again, off-again hacking at EmmyLua to meet my own needs. There's certainly been some squashing and interactive rebasing, but not enough.