From 62cdd6ba633a4bcef4ee707d944f2025ebec5435 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Thu, 13 Jan 2011 22:30:23 +0200
Subject: [PATCH] MonadTrans instances for GGHandler and GGWidget

---
 Yesod/Handler.hs | 3 +++
 Yesod/Widget.hs  | 6 +++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Yesod/Handler.hs b/Yesod/Handler.hs
index 85354d50..3847bbda 100644
--- a/Yesod/Handler.hs
+++ b/Yesod/Handler.hs
@@ -213,6 +213,9 @@ newtype GGHandler sub master m a =
         }
     deriving (Functor, Applicative, Monad, MonadIO, MonadPeelIO)
 
+instance MonadTrans (GGHandler s m) where
+    lift = GHandler . lift . lift . lift . lift
+
 type GHandler sub master = GGHandler sub master (Iteratee ByteString IO)
 
 type GHInner s m monad =
diff --git a/Yesod/Widget.hs b/Yesod/Widget.hs
index 62a7cd07..df33ea1b 100644
--- a/Yesod/Widget.hs
+++ b/Yesod/Widget.hs
@@ -52,7 +52,7 @@ import Yesod.Handler
     )
 import Control.Applicative (Applicative)
 import Control.Monad.IO.Class (MonadIO)
-import Control.Monad.Trans.Class (lift)
+import Control.Monad.Trans.Class (MonadTrans (lift))
 import Yesod.Internal
 import Yesod.Content (RepHtml (RepHtml), Content, toContent)
 import Control.Monad (liftM)
@@ -64,6 +64,10 @@ import Control.Monad.IO.Peel (MonadPeelIO)
 -- dependencies along with a 'StateT' to track unique identifiers.
 newtype GGWidget s m monad a = GWidget { unGWidget :: GWInner s m monad a }
     deriving (Functor, Applicative, Monad, MonadIO, MonadPeelIO)
+
+instance MonadTrans (GGWidget s m) where
+    lift = GWidget . lift . lift . lift . lift . lift . lift . lift . lift
+
 type GWidget s m = GGWidget s m (GHandler s m)
 type GWInner sub master monad =
     WriterT (Body (Route master)) (