ekmett/categories — Issue #1: fails to build under GHC 7.4
Author: stepcut
Created: 2012-02-06 22:56:00+00:00
State: open

Control/Category/Monoidal.hs fails with:

Control/Category/Monoidal.hs:44:19:
Expecting two more arguments to `k'
In the type `k (p (Id k p) a) a'
In the class declaration for `Monoidal'

Adding 'PolyKinds' to the Language pragma gets it to compile. However, this code from pipes fails:

class Monoidal k p => Multiplicative k p where
unit :: k (Id k p) a
mult :: k (p a a) a

with the error:

Control/Category/Monoidal.hs:44:19:
Expecting two more arguments to `k'
In the type `k (p (Id k p) a) a'
In the class declaration for `Monoidal'

Control/Category/Dual.hs could use a CPP in the Language pragma.

I am using:

categories-0.58.0.5
ghc-7.4.0.20120108 (aka, 7.4rc1)

perhaps the issue has been fixed in GHC 7.4.1. (Though it would still like the missing CPP in Dual.hs)