Matthew Lutze

I think this is reviewable at least. The one big consideration is what to do about unkinded types in error messages. My current idea is that we just use the...

> Which ASTs would use UnkindedType? Introduced in the `Resolver` and eliminated in the `Kinder` (the following phase)

> You want this merged, right? Yes, assuming we're in agreement on it in principle.

Strong "no". Seems like it would lead to bugs e.g. if I add a case to my enum.

Though maybe if an alternate syntax makes it clear that it's not exhaustive, it might be safer.

For example, I always forget the order of parameters in `List.foldLeft`'s function If it would pop up with something like: ```scala (x, y) ||> List.foldLeft($) ^ [f: (in, out) ->...

(Code block 2 edited by Matt)

> > We are updating the syntax such that `{ ... }` must always describe a concrete effect set. > > What is a concrete set? a subset of IO/NonDet/Pure...

I don't see any obvious errors, though the code is fairly complex so it's a little hard to follow. The nested application thing is to be expected. I think you...

> Hmm when does currying happen? It seems the three parameter function in the test is curried. I think lambdas are curried in the Weeder.