Yea bidirectional systems are nice - one of the big benefits is that you can also have polymorphic function arguments, something you can't do in standard HM. I

Yea bidirectional systems are nice - one of the big benefits is that you can also have polymorphic function arguments, something you can't do in standard HM. I recently implemented the bidirectional system in Rust from the paper you linked, it was fun (and a challenge!) [0] https://bit.ly/2W96K2r https://bit.ly/2W96K2r