diff --git a/yesod-core/Yesod/Core/Handler.hs b/yesod-core/Yesod/Core/Handler.hs
index a0230e18..d5c654f5 100644
--- a/yesod-core/Yesod/Core/Handler.hs
+++ b/yesod-core/Yesod/Core/Handler.hs
@@ -568,7 +568,7 @@ getMessages = do
   where
     enlist = pairup . S.split W8._nul
     pairup [] = []
-    pairup [x] = []
+    pairup [_] = []
     pairup (s:v:xs) = (decode s, preEscapedToHtml (decode v)) : pairup xs
     decode = decodeUtf8With lenientDecode
 
diff --git a/yesod-core/Yesod/Core/Internal/Session.hs b/yesod-core/Yesod/Core/Internal/Session.hs
index f8bc5f4d..247babd2 100644
--- a/yesod-core/Yesod/Core/Internal/Session.hs
+++ b/yesod-core/Yesod/Core/Internal/Session.hs
@@ -11,11 +11,9 @@ import qualified Web.ClientSession as CS
 import Data.Serialize
 import Data.Time
 import Data.ByteString (ByteString)
-import Control.Concurrent (forkIO, killThread, threadDelay)
-import Control.Monad (forever, guard)
+import Control.Monad (guard)
 import Yesod.Core.Types
 import Yesod.Core.Internal.Util
-import qualified Data.IORef as I
 import Control.AutoUpdate
 
 encodeClientSession :: CS.Key