[Haskell-beginners] problem installing checkers

[Britt Anderson]

I wanted to try reactive, but cabal install fails on checkers (a
dependency). Here is a portion of the error message, there are other
overlapping instances that follow. Can someone advise me how to
proceed. Thank you.

[13 of 15] Compiling Test.QuickCheck.Classes (
src/Test/QuickCheck/Classes.hs, dist/build/Test/QuickCheck/Classes.o )

src/Test/QuickCheck/Classes.hs:137:38:
    Overlapping instances for Show (a -> b)
      arising from a use of `property'
    Matching instances:
      instance Show (a -> b) -- Defined in Text.Show.Functions
      instance Show base:System.Event.Manager.IOCallback
        -- Defined in base:System.Event.Manager
    (The choice depends on the instantiation of `a, b'
     To pick the first instance above, use -XIncoherentInstances
     when compiling the other instance declarations)
    In the expression: property binopP
    In the expression: ("binop", property binopP)
    In the expression:
      [("identity", property identityP), ("binop", property binopP)]