Hello all, sorry I must have taken my stupid pills this morning, I cannot get the following code to compile, what am I missing? data MyState=MyState Integer newState:: (RandomGen g) => RandT g IO MyState newState = do time<-liftIO getCPUTime rand<-getRandomR (1,6) return $ MyState (time+rand) newStateIO :: IO MyState newStateIO = do r<-getStdGen evalRandT newState r -> Could not deduce (MonadIO (RandT g IO)) from the context (RandomGen g) arising from a use of `liftIO' at ...:4:15-31 Possible fix: add (MonadIO (RandT g IO)) to the context of the type signature for `newState' or add an instance declaration for (MonadIO (RandT g IO)) Pirates.hs /Pirates/src line 167 Problem But the MonadRandom docs say: Instances: MonadIOhttp://hackage.haskell.org/packages/archive/transformers/0.2.2.0/doc/html/Co... m => MonadIOhttp://hackage.haskell.org/packages/archive/transformers/0.2.2.0/doc/html/Co... (RandThttp://hackage.haskell.org/packages/archive/MonadRandom/0.1.6/doc/html/Contr... g m) And the MonadIO docs say: Instances: MonadIOhttp://hackage.haskell.org/packages/archive/transformers/0.2.2.0/doc/html/Co... IOhttp://hackage.haskell.org/packages/archive/base/4.3.1.0/doc/html/System-IO.... So it looks to me it should work! I've also tried to replace IO by MonadIO m=> in the signature, or remove all signatures. No joy. Thanks for any help. -- JP Moresmau http://jpmoresmau.blogspot.com/