Adelbert Chang

I've wanted filtering by author a couple time

> There's a lot of problems with Scalaz 8's encoding. It solves many, many problems, but the encoding is quite bulky, the type errors are unclear, and as you said...

One concern I have about this approach is it seems to be an ad-hoc mechanism nailed on top of the existing implicit resolver. Maybe such a concern is ill-founded, this...

I think a more convincing reason we don't define instances in the companion object of the type class specifically (defining it in the object for the data type is fine)...