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)]