Hi all, I'm working through Brown & Cook's "Monadic Memoization Mixins" and have come across some code that I can't get to compile with GHC. The error I get for arrayDict :: (*MArray *arr (*Maybe *b) m, *Ix *a, *Ord *a) => a -> arr a (*Maybe *b) -> *Dict *a b m is Non type-variable argument in the constraint: MArray arr (Maybe b) m (Use -XFlexibleContexts to permit this) In the type signature for `arrayDict': arrayDict :: (MArray arr (Maybe b) m, Ix a, Ord a) => a -> arr a (Maybe b) -> Dict a b m Enabling FlexibleContexts causes other errors. What could be going wrong? In case this isn't enough context, I've posted the full source code for this section of the paper at smipplehttp://www.smipple.net/snippet/Perry%20James/Monadic%20Memoization%20Mixins . Thanks in advance for any help, Perry