Re: [Haskell-cafe] Infrastructure for testing the impact of a Functor/Applicative/Monad hierarchy

Niklas Hambüchen writes:

Reading the other thread (Adding Applicative/Functor instances to all Monads in GHC) I was wondering if there was infrastructure for testing what effect making the often-discussed Functor/Monad change would have: How many packages on hackage would break etc.

Some patches for GHC/base are attached to http://hackage.haskell.org/trac/ghc/ticket/4834. They're a couple of years old, so they may not apply cleanly, but they might help you in assessing the impact of such a change.