diff --git a/Yesod/Core/Internal/Run.hs b/Yesod/Core/Internal/Run.hs
--- a/Yesod/Core/Internal/Run.hs
+++ b/Yesod/Core/Internal/Run.hs
@@ -46,7 +46,8 @@
 import           Yesod.Core.Internal.Request  (parseWaiRequest,
                                                tooLargeResponse)
 import           Yesod.Routes.Class           (Route, renderRoute)
-import Control.DeepSeq (($!!))
+import Control.DeepSeq (($!!), NFData)
+import Control.Monad (liftM)
 
 returnDeepSessionMap :: Monad m => SessionMap -> m SessionMap
 #if MIN_VERSION_bytestring(0, 10, 0)
diff --git a/yesod-core.cabal b/yesod-core.cabal
--- a/yesod-core.cabal
+++ b/yesod-core.cabal
@@ -1,5 +1,5 @@
 name:            yesod-core
-version:         1.4.0.1
+version:         1.4.0.2
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>