hi, thanks to Stefan, I am past the second problem in compiling this program (needed to change 'bounds' to 'getBounds'). now I get a more intimidating error message... I am trying to compile paradox 1.0, an older (GHC 5) Haskell program, with GHC 6.6.1. I get the intimidating error message shown below. I would appreciate any advice about how to fix this. I am guessing that the problem might be a change in the type of some library function. best regards, scott p.s. the file causing the error is in the paradox source code at http://www.cs.sunysb.edu/~stoller/out/paradox-1.0-casc.tar.gz Building paradox (release) Compiling: AnalysisTypes.hs Glasgow Haskell Compiler, Version 6.6.1, for Haskell 98, compiled by GHC version 6.6.1 Using package config file: /usr/local/lib/ghc-6.6.1/package.conf wired-in package base mapped to base-2.1.1 wired-in package rts mapped to rts-1.0 wired-in package haskell98 mapped to haskell98-1.0 wired-in package template-haskell mapped to template-haskell-2.1 Hsc static flags: -fauto-sccs-on-all-toplevs -static Created temporary directory: /tmp/ghc835_0 *** Checking old interface for main:AnalysisTypes: *** Parser: *** Renamer/typechecker: AnalysisTypes.hs:135:2: Inferred type is less polymorphic than expected Quantified type variable `s' is mentioned in the environment: m :: forall b. STRef s Int -> STRef s ((:=>) Symbol [TypeId s]) -> STRef s ((:=>) Symbol ([TypeId s], TypeId s)) -> STRef s ((:=>) Symbol (TypeId s)) -> (String -> ST s b) -> (a -> ST s b) -> ST s b (bound at AnalysisTypes.hs:284:6) In the first argument of `runST', namely `(do idfs <- newSTRef 0 preds <- newSTRef empty funs <- newSTRef empty vars <- newSTRef empty m idfs preds funs vars (\ s -> return (Left s)) (\ _ -> do ps' <- readSTRef preds fs' <- readSTRef funs ps <- sequence ([... | (p, ts') <- ...]) fs <- sequence ([... | (f, (ts', t')) <- ...]) typeIds' <- sequence ([... | t' <- ...]) let typeIds = ... names = ... typesAndTypeIds = ... types = ... typeIdToType = ... typeOfId tid = ... predTable = ... funTable = ... typeOfPred Equal = ... typeOfPred (p ::- _) = ... typeOfFun (f ::- _) = ... trans c = ... where ... return (Right (types, trans))))' In the expression: runST (do idfs <- newSTRef 0 preds <- newSTRef empty funs <- newSTRef empty vars <- newSTRef empty m idfs preds funs vars (\ s -> return (Left s)) (\ _ -> do ps' <- readSTRef preds fs' <- readSTRef funs ps <- sequence ([... | (p, ts') <- ...]) fs <- sequence ([... | (f, (ts', t')) <- ...]) typeIds' <- sequence ([... | t' <- ...]) let typeIds = ... names = ... typesAndTypeIds = ... types = ... typeIdToType = ... typeOfId tid = ... predTable = ... funTable = ... typeOfPred Equal = ... typeOfPred (p ::- _) = ... typeOfFun (f ::- _) = ... trans c = ... where ... return (Right (types, trans)))) In the definition of `runT': runT tm = runST (do idfs <- newSTRef 0 preds <- newSTRef empty funs <- newSTRef empty vars <- newSTRef empty m idfs preds funs vars (\ s -> return (Left s)) (\ _ -> do ps' <- ... fs' <- ... ps <- ... fs <- ... typeIds' <- ... let ... ...)) where MkT m = tm *** Deleting temp files: Deleting: /tmp/ghc835_0/ghc835_0.hc Warning: deleting non-existent /tmp/ghc835_0/ghc835_0.hc *** Deleting temp dirs: Deleting: /tmp/ghc835_0 make: *** [AnalysisTypes.o] Error 1