Hi folks, In GHC 7.6.3, the base Data.HashTable is deprecated, so I installed the hashtables package. In order to work on your datatype, you need an instance of Data.Hashable.Hashable. So I went to the Data.Hashable page and looked up examples on how to derive a Hashable instance for my datatype: http://hackage.haskell.org/packages/archive/hashable/latest/doc/html/Data-Ha... The problem occurs even when using the sample code on the page: {-# LANGUAGE DeriveGeneric #-} import GHC.Generics (Generic) import Data.Hashable data Colour = Red | Green | Blue deriving Generic instance Hashable Colour If I then type `hash Red` I get a stack overflow. I am using the Haskell Platform, so I have hashable-1.1.2.5, but I notice the docs are for hashable-1.2.0.10. If I install 1.2.0.10 though, other code in my project breaks - seems like one part doesn't recognize the instances from another part. So I'll stick with the platform version. I am running the 32-bit Windows GHC 7.6.3. Haskell Platform 2013.2.0.0. Any thoughts? Thanks, Lyle