Hello, I just tried building 0.7.8 today and got this error: src/Util/ContextMonad.hs:15:9: Overlapping instances for Error [String] arising from the superclasses of an instance declaration at src/Util/ContextMonad.hs:15:9-45 Matching instances: instance (transformers-0.2.1.0:Control.Monad.Trans.Error.ErrorList a) => Error [a] -- Defined in transformers-0.2.1.0:Control.Monad.Trans.Error instance [overlap ok] Error [String] -- Defined at src/Util/ContextMonad.hs:10:9-22 In the instance declaration for `ContextMonad String (Either [String])' Let me know if you need any more info. -- Live well, ~wren