Hello, cafe. I whant to switch to GHC 6.10 My application compiled fine with 6.8.3, but after switchin to 6.10, I've got errors about usage of catch function: Main.hs:165:14: Ambiguous type variable `e2' in the constraint: `Exception e2' arising from a use of `catch' at Main.hs:165:14-38 Probable fix: add a type signature that fixes these type variable(s) Main.hs:261:17: Ambiguous type variable `e' in the constraint: `Exception e' arising from a use of `handle' at Main.hs:261:17-118 Probable fix: add a type signature that fixes these type variable(s) Relevant places in code are: ... getNSteps f = do text <- get entryNSteps entryText catch (readIO text >>= f) $ \_e -> do msgBox (Just window) [] MessageWarning ButtonsOk $ "Число шагов указано неверно: " ++ show text return () ... loadData :: IO ([Term], Map.Map String Term) loadData = do examples <- handle (\_e -> msgBox Nothing [] MessageWarning ButtonsOk "Ошибка чтения файла примеров" >> return []) $ do examplesLines <- fmap lines $ readFile "examples.txt" let parsings :: [Term] parsings = concatMap (fromEither . parse) examplesLines parse :: String -> Either ParseError Term parse = Parsec.parse (Lambda.parser >>= \t -> skipMany space >> eof >> return t) "" fromEither :: Either ParseError Term -> [Term] fromEither = either (const []) (\t -> [t]) return parsings ... -- Victor