Folks, I have code like this that I want to test with QuickCheck but I'm having trouble imagining how I would wrap it up in a property. Do I make sure that id, subs, back are always morphed properly or do I leave that to separate properties for their respective types? Do I then ensure that array types are always unwrapped (see getType below), that a "series" variable is always declared, code added and a series reference returned? Last but not least, is monadic testing part of Test.QuickCheck.*? Thanks, Joel type Core a = State CoreUnit a data CoreUnit = Core { coreSym :: Integer -- starting # for gensym , coreVars :: M.Map String VarDecl , coreCode :: M.Map Integer [Statement] } deriving (Show, Eq) morphHistArrayAccess :: VarIdent -> Subscript -> BackRef -> C.Core C.Expr morphHistArrayAccess id subs back = do id' <- morph id subs' <- morph subs back' <- morph back (C.TyArray ty) <- getType id' s <- genSym "series" addVar s (C.TySeries ty) [] Nothing addCodeFront 1 [ C.AddToSeries (C.VarIdent s) (C.Var id' subs') ] return $ C.Series (C.VarIdent s) back' -- http://wagerlabs.com/