diff --git a/yesod-form/Yesod/Form/Class.hs b/yesod-form/Yesod/Form/Class.hs
index 039b3278..c9e8e8af 100644
--- a/yesod-form/Yesod/Form/Class.hs
+++ b/yesod-form/Yesod/Form/Class.hs
@@ -3,12 +3,12 @@
 {-# LANGUAGE TypeSynonymInstances #-}
 {-# LANGUAGE FlexibleContexts #-}
 module Yesod.Form.Class
-    ( ToForm (..)
-    , ToField (..)
+    ( {- FIXME ToForm (..)
+    , -} ToField (..)
     ) where
 
 import Text.Hamlet
-import Yesod.Widget (GGWidget)
+import Yesod.Widget (GGWidget, GWidget)
 import Yesod.Form.Fields
 import Yesod.Form.Types
 import Yesod.Form.Functions (areq, aopt)
@@ -19,11 +19,14 @@ import Yesod.Handler (GGHandler)
 import Yesod.Message (RenderMessage)
 import Control.Monad.IO.Class (MonadIO) -- FIXME
 
-class ToForm a master monad where
-    toForm :: AForm ([FieldView (GGWidget master monad ())] -> [FieldView (GGWidget master monad ())]) master monad a
+{-
+class ToForm a where
+    toForm :: AForm sub master a
+-}
 
-class ToField a master monad where
-    toField :: RenderMessage master msg => FieldSettings msg -> Maybe a -> AForm ([FieldView (GGWidget master monad ())] -> [FieldView (GGWidget master monad ())]) master monad a
+class ToField a master where
+    toField :: (RenderMessage master msg, RenderMessage master FormMessage)
+            => FieldSettings msg -> Maybe a -> AForm sub master a
 
 {- FIXME
 instance ToFormField String y where
@@ -32,44 +35,44 @@ instance ToFormField (Maybe String) y where
     toFormField = maybeStringField
 -}
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField Text master (GGHandler sub master m) where
+instance ToField Text master where
     toField = areq textField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe Text) master (GGHandler sub master m) where
+instance ToField (Maybe Text) master where
     toField = aopt textField
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField Int master (GGHandler sub master m) where
+instance ToField Int master where
     toField = areq intField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe Int) master (GGHandler sub master m) where
+instance ToField (Maybe Int) master where
     toField = aopt intField
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField Int64 master (GGHandler sub master m) where
+instance ToField Int64 master where
     toField = areq intField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe Int64) master (GGHandler sub master m) where
+instance ToField (Maybe Int64) master where
     toField = aopt intField
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField Double master (GGHandler sub master m) where
+instance ToField Double master where
     toField = areq doubleField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe Double) master (GGHandler sub master m) where
+instance ToField (Maybe Double) master where
     toField = aopt doubleField
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField Day master (GGHandler sub master m) where
+instance ToField Day master where
     toField = areq dayField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe Day) master (GGHandler sub master m) where
+instance ToField (Maybe Day) master where
     toField = aopt dayField
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField TimeOfDay master (GGHandler sub master m) where
+instance ToField TimeOfDay master where
     toField = areq timeField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe TimeOfDay) master (GGHandler sub master m) where
+instance ToField (Maybe TimeOfDay) master where
     toField = aopt timeField
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField Html master (GGHandler sub master m) where
+instance ToField Html master where
     toField = areq htmlField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe Html) master (GGHandler sub master m) where
+instance ToField (Maybe Html) master where
     toField = aopt htmlField
 
-instance (MonadIO m, RenderMessage master FormMessage) => ToField Textarea master (GGHandler sub master m) where
+instance ToField Textarea master where
     toField = areq textareaField
-instance (MonadIO m, RenderMessage master FormMessage) => ToField (Maybe Textarea) master (GGHandler sub master m) where
+instance ToField (Maybe Textarea) master where
     toField = aopt textareaField
 
 {- FIXME
diff --git a/yesod-form/Yesod/Form/Fields.hs b/yesod-form/Yesod/Form/Fields.hs
index ff9b5367..21784244 100644
--- a/yesod-form/Yesod/Form/Fields.hs
+++ b/yesod-form/Yesod/Form/Fields.hs
@@ -44,7 +44,6 @@ import Control.Monad (when, unless)
 import Data.List (intersect, nub)
 import Data.Either (rights)
 import Data.Maybe (catMaybes)
-import Data.String (IsString (..))
 
 import qualified Blaze.ByteString.Builder.Html.Utf8 as B
 import Blaze.ByteString.Builder (writeByteString, toLazyByteString)
@@ -89,7 +88,6 @@ data FormMessage = MsgInvalidInteger Text
                  | MsgInvalidBool Text
                  | MsgBoolYes
                  | MsgBoolNo
-                 | MsgOther Text
 
 defaultFormMessage :: FormMessage -> Text
 defaultFormMessage (MsgInvalidInteger t) = "Invalid integer: " `mappend` t
@@ -109,19 +107,14 @@ defaultFormMessage MsgSelectNone = "<None>"
 defaultFormMessage (MsgInvalidBool t) = "Invalid boolean: " `mappend` t
 defaultFormMessage MsgBoolYes = "Yes"
 defaultFormMessage MsgBoolNo = "No"
-defaultFormMessage (MsgOther t) = t
 
-instance IsString FormMessage where
-    fromString = MsgOther . fromString
-
-blank :: (Text -> Either msg a) -> [Text] -> IO (Either msg (Maybe a))
+blank :: (Monad m, RenderMessage master FormMessage)
+      => (Text -> Either FormMessage a) -> [Text] -> m (Either (SomeMessage master) (Maybe a))
 blank _ [] = return $ Right Nothing
 blank _ ("":_) = return $ Right Nothing
-blank f (x:_) = return $ either Left (Right . Just) $ f x
+blank f (x:_) = return $ either (Left . SomeMessage) (Right . Just) $ f x
 
-
-
-intField :: (Monad monad, Integral i) => Field (GGWidget master monad ()) FormMessage i
+intField :: (Integral i, RenderMessage master FormMessage) => Field sub master i
 intField = Field
     { fieldParse = blank $ \s ->
         case Data.Text.Read.signed Data.Text.Read.decimal s of
@@ -137,7 +130,7 @@ intField = Field
     showVal = either id (pack . showI)
     showI x = show (fromIntegral x :: Integer)
 
-doubleField :: Monad monad => Field (GGWidget master monad ()) FormMessage Double
+doubleField :: RenderMessage master FormMessage => Field sub master Double
 doubleField = Field
     { fieldParse = blank $ \s ->
         case Data.Text.Read.double s of
@@ -151,7 +144,7 @@ doubleField = Field
     }
   where showVal = either id (pack . show)
 
-dayField :: Monad monad => Field (GGWidget master monad ()) FormMessage Day
+dayField :: RenderMessage master FormMessage => Field sub master Day
 dayField = Field
     { fieldParse = blank $ parseDate . unpack
     , fieldView = \theId name val isReq -> addHamlet
@@ -161,7 +154,7 @@ dayField = Field
     }
   where showVal = either id (pack . show)
 
-timeField :: Monad monad => Field (GGWidget master monad ()) FormMessage TimeOfDay
+timeField :: RenderMessage master FormMessage => Field sub master TimeOfDay
 timeField = Field
     { fieldParse = blank $ parseTime . unpack
     , fieldView = \theId name val isReq -> addHamlet
@@ -176,7 +169,7 @@ timeField = Field
       where
         fullSec = fromInteger $ floor $ todSec tod
 
-htmlField :: Monad monad => Field (GGWidget master monad ()) FormMessage Html
+htmlField :: RenderMessage master FormMessage => Field sub master Html
 htmlField = Field
     { fieldParse = blank $ Right . preEscapedString . sanitizeBalance . unpack -- FIXME make changes to xss-sanitize
     , fieldView = \theId name val _isReq -> addHamlet
@@ -204,7 +197,7 @@ instance ToHtml Textarea where
         writeHtmlEscapedChar '\n' = writeByteString "<br>"
         writeHtmlEscapedChar c    = B.writeHtmlEscapedChar c
 
-textareaField :: Monad monad => Field (GGWidget master monad ()) FormMessage Textarea
+textareaField :: RenderMessage master FormMessage => Field sub master Textarea
 textareaField = Field
     { fieldParse =  blank $ Right . Textarea
     , fieldView = \theId name val _isReq -> addHamlet
@@ -213,7 +206,7 @@ textareaField = Field
 |]
     }
 
-hiddenField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
+hiddenField :: RenderMessage master FormMessage => Field sub master Text
 hiddenField = Field
     { fieldParse = blank $ Right
     , fieldView = \theId name val _isReq -> addHamlet
@@ -222,7 +215,7 @@ hiddenField = Field
 |]
     }
 
-textField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
+textField :: RenderMessage master FormMessage => Field sub master Text
 textField = Field
     { fieldParse = blank $ Right
     , fieldView = \theId name val isReq ->
@@ -231,7 +224,7 @@ textField = Field
 |]
     }
 
-passwordField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
+passwordField :: RenderMessage master FormMessage => Field sub master Text
 passwordField = Field
     { fieldParse = blank $ Right
     , fieldView = \theId name val isReq -> addHamlet
@@ -278,7 +271,7 @@ parseTimeHelper (h1, h2, m1, m2, s1, s2)
     m = read [m1, m2]
     s = fromInteger $ read [s1, s2]
 
-emailField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
+emailField :: RenderMessage master FormMessage => Field sub master Text
 emailField = Field
     { fieldParse = blank $
         \s -> if Email.isValid (unpack s)
@@ -291,9 +284,9 @@ emailField = Field
     }
 
 type AutoFocus = Bool
-searchField :: Monad monad => AutoFocus -> Field (GGWidget master monad ()) FormMessage Text
+searchField :: RenderMessage master FormMessage => AutoFocus -> Field sub master Text
 searchField autoFocus = Field
-    { fieldParse =  blank Right
+    { fieldParse = blank Right
     , fieldView = \theId name val isReq -> do
         [WHAMLET|\
 <input id="#{theId}" name="#{name}" type="search" :isReq:required="" :autoFocus:autofocus="" value="#{either id id val}">
@@ -307,7 +300,7 @@ searchField autoFocus = Field
             |]
     }
 
-urlField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
+urlField :: RenderMessage master FormMessage => Field sub master Text
 urlField = Field
     { fieldParse = blank $ \s ->
         case parseURI $ unpack s of
@@ -319,18 +312,18 @@ urlField = Field
 |]
     }
 
-selectField :: (Eq a, Monad monad, RenderMessage master FormMessage) => [(Text, a)] -> Field (GGWidget master (GGHandler sub master monad) ()) FormMessage a
+selectField :: (Eq a, RenderMessage master FormMessage) => [(Text, a)] -> Field sub master a
 selectField = selectFieldHelper
     (\theId name inside -> [WHAMLET|<select ##{theId} name=#{name}>^{inside}|])
     (\_theId _name isSel -> [WHAMLET|<option value=none :isSel:selected>_{MsgSelectNone}|])
     (\_theId _name value isSel text -> [WHAMLET|<option value=#{value} :isSel:selected>#{text}|])
 
-multiSelectField :: (Show a, Eq a, Monad monad, RenderMessage master FormMessage) => [(Text, a)] -> Field (GGWidget master (GGHandler sub master monad) ()) FormMessage [a]
+multiSelectField :: (Show a, Eq a, RenderMessage master FormMessage) => [(Text, a)] -> Field sub master [a]
 multiSelectField = multiSelectFieldHelper
     (\theId name inside -> [WHAMLET|<select ##{theId} multiple name=#{name}>^{inside}|])
     (\_theId _name value isSel text -> [WHAMLET|<option value=#{value} :isSel:selected>#{text}|])
 
-radioField :: (Eq a, Monad monad, RenderMessage master FormMessage) => [(Text, a)] -> Field (GGWidget master (GGHandler sub master monad) ()) FormMessage a
+radioField :: (Eq a, RenderMessage master FormMessage) => [(Text, a)] -> Field sub master a
 radioField = selectFieldHelper
     (\theId _name inside -> [WHAMLET|<div ##{theId}>^{inside}|])
     (\theId name isSel -> [WHAMLET|
@@ -344,7 +337,7 @@ radioField = selectFieldHelper
     <label for=#{theId}-#{value}>#{text}
 |])
 
-boolField :: (Monad monad, RenderMessage master FormMessage) => Field (GGWidget master (GGHandler sub master monad) ()) FormMessage Bool
+boolField :: RenderMessage master FormMessage => Field sub master Bool
 boolField = Field
       { fieldParse = return . boolParser
       , fieldView = \theId name val isReq -> [WHAMLET|
@@ -367,13 +360,13 @@ boolField = Field
       "none" -> Right Nothing
       "yes" -> Right $ Just True
       "no" -> Right $ Just False
-      t -> Left $ MsgInvalidBool t
+      t -> Left $ SomeMessage $ MsgInvalidBool t
     showVal = either (\_ -> False)
 
-multiSelectFieldHelper :: (Show a, Eq a, Monad monad)
-        => (Text -> Text -> GGWidget master monad () -> GGWidget master monad ())
-        -> (Text -> Text -> Text -> Bool -> Text -> GGWidget master monad ())
-        -> [(Text, a)] -> Field (GGWidget master monad ()) FormMessage [a]
+multiSelectFieldHelper :: (Show a, Eq a)
+        => (Text -> Text -> GWidget sub master () -> GWidget sub master ())
+        -> (Text -> Text -> Text -> Bool -> Text -> GWidget sub master ())
+        -> [(Text, a)] -> Field sub master [a]
 multiSelectFieldHelper outside inside opts = Field
     { fieldParse = return . selectParser
     , fieldView = \theId name vals _ ->
@@ -393,11 +386,12 @@ multiSelectFieldHelper outside inside opts = Field
     selectParser xs | not $ null (["", "none"] `intersect` xs) = Right Nothing
                     | otherwise = (Right . Just . map snd . catMaybes . map (\y -> lookup y pairs) . nub . map fst . rights . map Data.Text.Read.decimal) xs
 
-selectFieldHelper :: (Eq a, Monad monad)
-        => (Text -> Text -> GGWidget master monad () -> GGWidget master monad ())
-        -> (Text -> Text -> Bool -> GGWidget master monad ())
-        -> (Text -> Text -> Text -> Bool -> Text -> GGWidget master monad ())
-        -> [(Text, a)] -> Field (GGWidget master monad ()) FormMessage a
+selectFieldHelper
+        :: (Eq a, RenderMessage master FormMessage)
+        => (Text -> Text -> GWidget sub master () -> GWidget sub master ())
+        -> (Text -> Text -> Bool -> GWidget sub master ())
+        -> (Text -> Text -> Text -> Bool -> Text -> GWidget sub master ())
+        -> [(Text, a)] -> Field sub master a
 selectFieldHelper outside onOpt inside opts = Field
     { fieldParse = return . selectParser
     , fieldView = \theId name val isReq ->
@@ -422,6 +416,6 @@ selectFieldHelper outside onOpt inside opts = Field
             x -> case Data.Text.Read.decimal x of
                     Right (a, "") ->
                         case lookup a pairs of
-                            Nothing -> Left $ MsgInvalidEntry x
+                            Nothing -> Left $ SomeMessage $ MsgInvalidEntry x
                             Just y -> Right $ Just $ snd y
-                    _ -> Left $ MsgInvalidNumber x
+                    _ -> Left $ SomeMessage $ MsgInvalidNumber x
diff --git a/yesod-form/Yesod/Form/Functions.hs b/yesod-form/Yesod/Form/Functions.hs
index e2e87bfc..3cd3e4a6 100644
--- a/yesod-form/Yesod/Form/Functions.hs
+++ b/yesod-form/Yesod/Form/Functions.hs
@@ -38,15 +38,15 @@ import Control.Monad.Trans.Class (lift)
 import Control.Monad (liftM, join)
 import Text.Blaze (Html, toHtml)
 import Yesod.Handler (GHandler, GGHandler, getRequest, runRequestBody, newIdent, getYesod)
-import Yesod.Core (RenderMessage)
-import Yesod.Widget (GGWidget, whamlet)
+import Yesod.Core (RenderMessage, liftIOHandler)
+import Yesod.Widget (GWidget, GGWidget, whamlet)
 import Yesod.Request (reqNonce, reqWaiRequest, reqGetParams, languages)
 import Network.Wai (requestMethod)
 import Text.Hamlet (html)
 import Data.Monoid (mempty)
 import Data.Maybe (listToMaybe)
 import Yesod.Message (RenderMessage (..))
-import Control.Monad.IO.Class (MonadIO, liftIO) -- FIXME
+import Control.Monad.IO.Class (MonadIO, liftIO)
 
 #if __GLASGOW_HASKELL__ >= 700
 #define WHAMLET whamlet
@@ -57,7 +57,7 @@ import Control.Monad.IO.Class (MonadIO, liftIO) -- FIXME
 #endif
 
 -- | Get a unique identifier.
-newFormIdent :: Monad m => Form msg m Text
+newFormIdent :: Form sub master Text
 newFormIdent = do
     i <- get
     let i' = incrInts i
@@ -67,12 +67,12 @@ newFormIdent = do
     incrInts (IntSingle i) = IntSingle $ i + 1
     incrInts (IntCons i is) = (i + 1) `IntCons` is
 
-formToAForm :: Monad m => Form msg m (FormResult a, xml) -> AForm ([xml] -> [xml]) msg m a
+formToAForm :: Form sub master (FormResult a, FieldView sub master) -> AForm sub master a
 formToAForm form = AForm $ \(master, langs) env ints -> do
     ((a, xml), ints', enc) <- runRWST form (env, master, langs) ints
     return (a, (:) xml, ints', enc)
 
-aFormToForm :: Monad m => AForm xml msg m a -> Form msg m (FormResult a, xml)
+aFormToForm :: AForm sub master a -> Form sub master (FormResult a, [FieldView sub master] -> [FieldView sub master])
 aFormToForm (AForm aform) = do
     ints <- get
     (env, master, langs) <- ask
@@ -81,34 +81,34 @@ aFormToForm (AForm aform) = do
     tell enc
     return (a, xml)
 
-askParams :: Monad m => Form msg m (Maybe Env)
+askParams :: Form sub master (Maybe Env)
 askParams = do
     (x, _, _) <- ask
     return $ liftM fst x
 
-askFiles :: Monad m => Form msg m (Maybe FileEnv)
+askFiles :: Form sub master (Maybe FileEnv)
 askFiles = do
     (x, _, _) <- ask
     return $ liftM snd x
 
-mreq :: (MonadIO m, RenderMessage master msg, RenderMessage master msg2, RenderMessage master FormMessage)
-     => Field xml msg a -> FieldSettings msg2 -> Maybe a
-     -> Form master (GGHandler sub master m) (FormResult a, FieldView xml)
+mreq :: (RenderMessage master msg, RenderMessage master FormMessage)
+     => Field sub master a -> FieldSettings msg -> Maybe a
+     -> Form sub master (FormResult a, FieldView sub master)
 mreq field fs mdef = mhelper field fs mdef (\m l -> FormFailure [renderMessage m l MsgValueRequired]) FormSuccess True
 
-mopt :: (MonadIO m, RenderMessage master msg, RenderMessage master msg2)
-     => Field xml msg a -> FieldSettings msg2 -> Maybe (Maybe a)
-     -> Form master (GGHandler sub master m) (FormResult (Maybe a), FieldView xml)
+mopt :: RenderMessage master msg
+     => Field sub master a -> FieldSettings msg -> Maybe (Maybe a)
+     -> Form sub master (FormResult (Maybe a), FieldView sub master)
 mopt field fs mdef = mhelper field fs (join mdef) (const $ const $ FormSuccess Nothing) (FormSuccess . Just) False
 
-mhelper :: (MonadIO m, RenderMessage master msg, RenderMessage master msg2)
-        => Field xml msg a
-        -> FieldSettings msg2
+mhelper :: RenderMessage master msg
+        => Field sub master a
+        -> FieldSettings msg
         -> Maybe a
         -> (master -> [Text] -> FormResult b) -- ^ on missing
         -> (a -> FormResult b) -- ^ on success
         -> Bool -- ^ is it required?
-        -> Form master (GGHandler sub master m) (FormResult b, FieldView xml)
+        -> Form sub master (FormResult b, FieldView sub master)
 
 mhelper Field {..} FieldSettings {..} mdef onMissing onFound isReq = do
     mp <- askParams
@@ -121,9 +121,9 @@ mhelper Field {..} FieldSettings {..} mdef onMissing onFound isReq = do
             Nothing -> return (FormMissing, maybe (Left "") Right mdef)
             Just p -> do
                 let mvals = map snd $ filter (\(n,_) -> n == name) p
-                emx <- liftIO $ fieldParse mvals
+                emx <- lift $ fieldParse mvals
                 return $ case emx of
-                    Left e -> (FormFailure [renderMessage master langs e], maybe (Left "") Left (listToMaybe mvals))
+                    Left (SomeMessage e) -> (FormFailure [renderMessage master langs e], maybe (Left "") Left (listToMaybe mvals))
                     Right mx ->
                         case mx of
                             Nothing -> (onMissing master langs, Left "")
@@ -140,18 +140,20 @@ mhelper Field {..} FieldSettings {..} mdef onMissing onFound isReq = do
         , fvRequired = isReq
         })
 
-areq :: (MonadIO m, RenderMessage master msg1, RenderMessage master msg2, RenderMessage master FormMessage)
-     => Field xml msg1 a -> FieldSettings msg2 -> Maybe a
-     -> AForm ([FieldView xml] -> [FieldView xml]) master (GGHandler sub master m) a
+areq :: (RenderMessage master msg, RenderMessage master FormMessage)
+     => Field sub master a -> FieldSettings msg -> Maybe a
+     -> AForm sub master a
 areq a b = formToAForm . mreq a b
 
-aopt :: (MonadIO m, RenderMessage master msg1, RenderMessage master msg2)
-     => Field xml msg1 a -> FieldSettings msg2 -> Maybe (Maybe a)
-     -> AForm ([FieldView xml] -> [FieldView xml]) master (GGHandler sub master m) (Maybe a)
+aopt :: RenderMessage master msg
+     => Field sub master a
+     -> FieldSettings msg
+     -> Maybe (Maybe a)
+     -> AForm sub master (Maybe a)
 aopt a b = formToAForm . mopt a b
 
-runFormGeneric :: Monad m => Form master m a -> master -> [Text] -> Maybe (Env, FileEnv) -> m (a, Enctype)
-runFormGeneric form master langs env = evalRWST form (env, master, langs) (IntSingle 1)
+runFormGeneric :: MonadIO m => Form sub master a -> master -> [Text] -> Maybe (Env, FileEnv) -> GGHandler sub master m (a, Enctype)
+runFormGeneric form master langs env = liftIOHandler $ evalRWST form (env, master, langs) (IntSingle 1)
 
 -- | This function is used to both initially render a form and to later extract
 -- results from it. Note that, due to CSRF protection and a few other issues,
@@ -163,7 +165,8 @@ runFormGeneric form master langs env = evalRWST form (env, master, langs) (IntSi
 -- the form submit to a POST page. In such a case, both the GET and POST
 -- handlers should use 'runFormPost'.
 runFormPost :: RenderMessage master FormMessage
-            => (Html -> Form master (GHandler sub master) (FormResult a, xml)) -> GHandler sub master ((FormResult a, xml), Enctype)
+            => (Html -> Form sub master (FormResult a, xml))
+            -> GHandler sub master ((FormResult a, xml), Enctype)
 runFormPost form = do
     req <- getRequest
     let nonceKey = "_nonce"
@@ -185,7 +188,7 @@ runFormPost form = do
                 _ -> res
     return ((res', xml), enctype)
 
-runFormPostNoNonce :: (Html -> Form master (GHandler sub master) (FormResult a, xml)) -> GHandler sub master ((FormResult a, xml), Enctype)
+runFormPostNoNonce :: (Html -> Form sub master (FormResult a, xml)) -> GHandler sub master ((FormResult a, xml), Enctype)
 runFormPostNoNonce form = do
     req <- getRequest
     env <- if requestMethod (reqWaiRequest req) == "GET"
@@ -195,7 +198,7 @@ runFormPostNoNonce form = do
     m <- getYesod
     runFormGeneric (form mempty) m langs env
 
-runFormGet :: Monad m => (Html -> Form master (GGHandler sub master m) a) -> GGHandler sub master m (a, Enctype)
+runFormGet :: (Html -> Form sub master a) -> GHandler sub master (a, Enctype)
 runFormGet form = do
     let key = "_hasdata"
     let fragment = [HTML|<input type=hidden name=#{key}>|]
@@ -208,12 +211,12 @@ runFormGet form = do
     m <- getYesod
     runFormGeneric (form fragment) m langs env
 
-type FormRender master msg m a =
-       AForm ([FieldView (GGWidget master m ())] -> [FieldView (GGWidget master m ())]) msg m a
+type FormRender sub master a =
+       AForm sub master a
     -> Html
-    -> Form msg m (FormResult a, GGWidget master m ())
+    -> Form sub master (FormResult a, GWidget sub master ())
 
-renderTable, renderDivs :: Monad m => FormRender master msg m a
+renderTable, renderDivs :: FormRender sub master a
 renderTable aform fragment = do
     (res, views') <- aFormToForm aform
     let views = views' []
@@ -248,19 +251,24 @@ $forall view <- views
 |]
     return (res, widget)
 
-check :: (a -> Either msg a) -> Field xml msg a -> Field xml msg a
+check :: RenderMessage master msg
+      => (a -> Either msg a) -> Field sub master a -> Field sub master a
 check f = checkM $ return . f
 
 -- | Return the given error message if the predicate is false.
-checkBool :: (a -> Bool) -> msg -> Field xml msg a -> Field xml msg a
+checkBool :: RenderMessage master msg
+          => (a -> Bool) -> msg -> Field sub master a -> Field sub master a
 checkBool b s = check $ \x -> if b x then Right x else Left s
 
-checkM :: (a -> IO (Either msg a)) -> Field xml msg a -> Field xml msg a
+checkM :: RenderMessage master msg
+       => (a -> GGHandler sub master IO (Either msg a))
+       -> Field sub master a
+       -> Field sub master a
 checkM f field = field
     { fieldParse = \ts -> do
         e1 <- fieldParse field ts
         case e1 of
             Left msg -> return $ Left msg
             Right Nothing -> return $ Right Nothing
-            Right (Just a) -> fmap (either Left (Right . Just)) $ f a
+            Right (Just a) -> fmap (either (Left . SomeMessage) (Right . Just)) $ f a
     }
diff --git a/yesod-form/Yesod/Form/Input.hs b/yesod-form/Yesod/Form/Input.hs
index 2eb5b1eb..ba8eeec0 100644
--- a/yesod-form/Yesod/Form/Input.hs
+++ b/yesod-form/Yesod/Form/Input.hs
@@ -12,18 +12,17 @@ import Yesod.Form.Types
 import Yesod.Form.Fields (FormMessage (MsgInputNotFound))
 import Data.Text (Text)
 import Control.Applicative (Applicative (..))
-import Yesod.Handler (GHandler, GGHandler, invalidArgs, runRequestBody, getRequest, getYesod)
+import Yesod.Handler (GHandler, GGHandler, invalidArgs, runRequestBody, getRequest, getYesod, liftIOHandler)
 import Yesod.Request (reqGetParams, languages)
 import Control.Monad (liftM)
 import Yesod.Widget (GWidget)
 import Yesod.Message (RenderMessage (..))
-import Control.Monad.IO.Class (MonadIO, liftIO) -- FIXME
 
 type DText = [Text] -> [Text]
-newtype FormInput master a = FormInput { unFormInput :: master -> [Text] -> Env -> IO (Either DText a) }
-instance Functor (FormInput master) where
+newtype FormInput sub master a = FormInput { unFormInput :: master -> [Text] -> Env -> GGHandler sub master IO (Either DText a) }
+instance Functor (FormInput sub master) where
     fmap a (FormInput f) = FormInput $ \c d e -> fmap (either Left (Right . a)) $ f c d e
-instance Applicative (FormInput master) where
+instance Applicative (FormInput sub master) where
     pure = FormInput . const . const . const . return . Right
     (FormInput f) <*> (FormInput x) = FormInput $ \c d e -> do
         res1 <- f c d e
@@ -34,39 +33,39 @@ instance Applicative (FormInput master) where
             (_, Left b) -> Left b
             (Right a, Right b) -> Right $ a b
 
-ireq :: (RenderMessage master msg, RenderMessage master FormMessage) => Field (GWidget sub master ()) msg a -> Text -> FormInput master a
+ireq :: (RenderMessage master msg, RenderMessage master FormMessage) => Field sub master a -> Text -> FormInput sub master a
 ireq field name = FormInput $ \m l env -> do
       let filteredEnv = map snd $ filter (\y -> fst y == name) env
       emx <- fieldParse field $ filteredEnv
       return $ case emx of
-          Left e -> Left $ (:) $ renderMessage m l e
+          Left (SomeMessage e) -> Left $ (:) $ renderMessage m l e
           Right Nothing -> Left $ (:) $ renderMessage m l $ MsgInputNotFound name
           Right (Just a) -> Right a
 
-iopt :: RenderMessage master msg => Field (GWidget sub master ()) msg a -> Text -> FormInput master (Maybe a)
+iopt :: RenderMessage master msg => Field sub master a -> Text -> FormInput sub master (Maybe a)
 iopt field name = FormInput $ \m l env -> do
       let filteredEnv = map snd $ filter (\y -> fst y == name) env
       emx <- fieldParse field $ filteredEnv
       return $ case emx of
-        Left e -> Left $ (:) $ renderMessage m l e
+        Left (SomeMessage e) -> Left $ (:) $ renderMessage m l e
         Right x -> Right x
 
-runInputGet :: MonadIO monad => FormInput master a -> GGHandler sub master monad a
+runInputGet :: FormInput sub master a -> GHandler sub master a
 runInputGet (FormInput f) = do
     env <- liftM reqGetParams getRequest
     m <- getYesod
     l <- languages
-    emx <- liftIO $ f m l env
+    emx <- liftIOHandler $ f m l env
     case emx of
         Left errs -> invalidArgs $ errs []
         Right x -> return x
 
-runInputPost :: FormInput master a -> GHandler sub master a
+runInputPost :: FormInput sub master a -> GHandler sub master a
 runInputPost (FormInput f) = do
     env <- liftM fst runRequestBody
     m <- getYesod
     l <- languages
-    emx <- liftIO $ f m l env
+    emx <- liftIOHandler $ f m l env
     case emx of
         Left errs -> invalidArgs $ errs []
         Right x -> return x
diff --git a/yesod-form/Yesod/Form/MassInput.hs b/yesod-form/Yesod/Form/MassInput.hs
index 11ccb074..562fc84a 100644
--- a/yesod-form/Yesod/Form/MassInput.hs
+++ b/yesod-form/Yesod/Form/MassInput.hs
@@ -12,9 +12,9 @@ module Yesod.Form.MassInput
 import Yesod.Form.Types
 import Yesod.Form.Functions
 import Yesod.Form.Fields (boolField, FormMessage)
-import Yesod.Widget (GGWidget, whamlet)
+import Yesod.Widget (GWidget, GGWidget, whamlet)
 import Yesod.Message (RenderMessage)
-import Yesod.Handler (newIdent, GGHandler)
+import Yesod.Handler (newIdent, GHandler, GGHandler)
 import Text.Blaze (Html)
 import Control.Monad.Trans.Class (lift)
 import Data.Text (pack, Text)
@@ -50,11 +50,11 @@ up i = do
         IntCons _ is' -> put is' >> newFormIdent >> return ()
     up $ i - 1
 
-inputList :: (MonadIO mo, m ~ GGHandler sub master mo, xml ~ GGWidget master (GGHandler sub master mo) (), RenderMessage master FormMessage)
+inputList :: (m ~ GGHandler sub master IO, xml ~ GWidget sub master (), RenderMessage master FormMessage)
           => Html
-          -> ([[FieldView xml]] -> xml)
-          -> (Maybe a -> AForm ([FieldView xml] -> [FieldView xml]) master m a)
-          -> (Maybe [a] -> AForm ([FieldView xml] -> [FieldView xml]) master m [a])
+          -> ([[FieldView sub master]] -> xml)
+          -> (Maybe a -> AForm sub master a)
+          -> (Maybe [a] -> AForm sub master [a])
 inputList label fixXml single mdef = formToAForm $ do
     theId <- lift newIdent
     down 1
@@ -93,9 +93,9 @@ inputList label fixXml single mdef = formToAForm $ do
         , fvRequired = False
         })
 
-withDelete :: (MonadIO mo, xml ~ GGWidget master m (), m ~ GGHandler sub master mo, Monad mo, RenderMessage master FormMessage)
-           => AForm ([FieldView xml] -> [FieldView xml]) master m a
-           -> Form master m (Either xml (FormResult a, [FieldView xml]))
+withDelete :: (xml ~ GWidget sub master (), RenderMessage master FormMessage)
+           => AForm sub master a
+           -> Form sub master (Either xml (FormResult a, [FieldView sub master]))
 withDelete af = do
     down 1
     deleteName <- newFormIdent
@@ -114,9 +114,9 @@ withDelete af = do
     up 1
     return res
 
-fixme :: (xml ~ GGWidget master (GGHandler sub master mo) ())
-      => [Either xml (FormResult a, [FieldView xml])]
-      -> (FormResult [a], [xml], [[FieldView xml]])
+fixme :: (xml ~ GWidget sub master ())
+      => [Either xml (FormResult a, [FieldView sub master])]
+      -> (FormResult [a], [xml], [[FieldView sub master]])
 fixme eithers =
     (res, xmls, map snd rest)
   where
@@ -124,9 +124,8 @@ fixme eithers =
     res = sequenceA $ map fst rest
 
 massDivs, massTable
-         :: Monad m
-         => [[FieldView (GGWidget master m ())]]
-         -> GGWidget master m ()
+         :: [[FieldView sub master]]
+         -> GWidget sub master ()
 massDivs viewss = [WHAMLET|
 $forall views <- viewss
     <fieldset>
diff --git a/yesod-form/Yesod/Form/Types.hs b/yesod-form/Yesod/Form/Types.hs
index 37dcc062..52063d13 100644
--- a/yesod-form/Yesod/Form/Types.hs
+++ b/yesod-form/Yesod/Form/Types.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE ExistentialQuantification #-}
 module Yesod.Form.Types
     ( -- * Helpers
       Enctype (..)
@@ -11,6 +12,7 @@ module Yesod.Form.Types
     , Form
     , AForm (..)
       -- * Build forms
+    , SomeMessage (..)
     , Field (..)
     , FieldSettings (..)
     , FieldView (..)
@@ -24,7 +26,7 @@ import Text.Blaze (Html, ToHtml (toHtml))
 import Control.Applicative ((<$>), Applicative (..))
 import Control.Monad (liftM)
 import Data.String (IsString (..))
-import Control.Monad.Trans.Class (MonadTrans (..))
+import Yesod.Core (RenderMessage, GGHandler, GWidget)
 
 -- | A form can produce three different results: there was no data available,
 -- the data was invalid, or there was a successful parse.
@@ -70,32 +72,29 @@ instance Show Ints where
 type Env = [(Text, Text)] -- FIXME use a Map
 type FileEnv = [(Text, FileInfo)]
 
-type Form master m a = RWST (Maybe (Env, FileEnv), master, [Text]) Enctype Ints m a
+type Lang = Text
+type Form sub master a = RWST (Maybe (Env, FileEnv), master, [Lang]) Enctype Ints (GGHandler sub master IO) a
 
-newtype AForm xml master m a = AForm
-    { unAForm :: (master, [Text]) -> Maybe (Env, FileEnv) -> Ints -> m (FormResult a, xml, Ints, Enctype)
+newtype AForm sub master a = AForm
+    { unAForm :: (master, [Text]) -> Maybe (Env, FileEnv) -> Ints -> GGHandler sub master IO (FormResult a, [FieldView sub master] -> [FieldView sub master], Ints, Enctype)
     }
-instance Monad m => Functor (AForm xml msg m) where
+instance Functor (AForm sub master) where
     fmap f (AForm a) =
         AForm $ \x y z -> liftM go $ a x y z
       where
         go (w, x, y, z) = (fmap f w, x, y, z)
-instance (Monad m, Monoid xml) => Applicative (AForm xml msg m) where
+instance Applicative (AForm sub master) where
     pure x = AForm $ const $ const $ \ints -> return (FormSuccess x, mempty, ints, mempty)
     (AForm f) <*> (AForm g) = AForm $ \mr env ints -> do
         (a, b, ints', c) <- f mr env ints
         (x, y, ints'', z) <- g mr env ints'
         return (a <*> x, b `mappend` y, ints'', c `mappend` z)
-instance (Monad m, Monoid xml, Monoid a) => Monoid (AForm xml msg m a) where
+instance Monoid a => Monoid (AForm sub master a) where
     mempty = pure mempty
     mappend a b = mappend <$> a <*> b
-instance Monoid xml => MonadTrans (AForm xml msg) where
-    lift mx = AForm $ const $ const $ \ints -> do
-        x <- mx
-        return (pure x, mempty, ints, mempty)
 
 data FieldSettings msg = FieldSettings
-    { fsLabel :: msg
+    { fsLabel :: msg -- FIXME switch to SomeMessage?
     , fsTooltip :: Maybe msg
     , fsId :: Maybe Text
     , fsName :: Maybe Text
@@ -104,21 +103,23 @@ data FieldSettings msg = FieldSettings
 instance (a ~ Text) => IsString (FieldSettings a) where
     fromString s = FieldSettings (fromString s) Nothing Nothing Nothing
 
-data FieldView xml = FieldView
+data FieldView sub master = FieldView
     { fvLabel :: Html
     , fvTooltip :: Maybe Html
     , fvId :: Text
-    , fvInput :: xml
+    , fvInput :: GWidget sub master ()
     , fvErrors :: Maybe Html
     , fvRequired :: Bool
     }
 
-data Field xml msg a = Field
-    { fieldParse :: [Text] -> IO (Either msg (Maybe a)) -- FIXME
+data SomeMessage master = forall msg. RenderMessage master msg => SomeMessage msg
+
+data Field sub master a = Field
+    { fieldParse :: [Text] -> GGHandler sub master IO (Either (SomeMessage master) (Maybe a))
     -- | ID, name, (invalid text OR legimiate result), required?
     , fieldView :: Text
                 -> Text
                 -> Either Text a
                 -> Bool
-                -> xml
+                -> GWidget sub master ()
     }
diff --git a/yesod-form/hello-forms.hs b/yesod-form/hello-forms.hs
index c96bc9e7..45f8c477 100644
--- a/yesod-form/hello-forms.hs
+++ b/yesod-form/hello-forms.hs
@@ -8,6 +8,7 @@ import Data.Text (Text, pack)
 import Network.Wai.Handler.Warp (run)
 import Data.Time (utctDay, getCurrentTime)
 import qualified Data.Text as T
+import Control.Monad.IO.Class (liftIO)
 
 data Fruit = Apple | Banana | Pear
     deriving (Show, Enum, Bounded, Eq)
@@ -77,13 +78,13 @@ getMassR = do
 |]
 
 myValidForm = fixType $ runFormGet $ renderTable $ pure (,,)
-    <*> areq (check (\x -> if T.length x < 3 then Left "Need at least 3 letters" else Right x) textField) "Name" Nothing
-    <*> areq (checkBool (>= 18) "Must be 18 or older" intField) "Age" Nothing
+    <*> areq (check (\x -> if T.length x < 3 then Left ("Need at least 3 letters" :: Text) else Right x) textField) "Name" Nothing
+    <*> areq (checkBool (>= 18) ("Must be 18 or older" :: Text) intField) "Age" Nothing
     <*> areq (checkM inPast dayField) "Anniversary" Nothing
   where
     inPast x = do
-        now <- getCurrentTime
-        return $ if utctDay now < x then Left "Need a date in the past" else Right x
+        now <- liftIO $ getCurrentTime
+        return $ if utctDay now < x then Left ("Need a date in the past" :: Text) else Right x
 
 getValidR = do
     ((res, form), enctype) <- myValidForm