Better signature for errorHandler

Yesod/Dispatch.hs

@@ -251,14 +251,14 @@ toWaiApp' y segments env = do
     onRequest y rr
     let h =
           case eurl of
-            Left _ -> errorHandler y NotFound
+            Left _ -> errorHandler NotFound
             Right url -> do
                 -- FIXME auth <- isAuthorized y url
                 case handleSite site render url method of
-                    Nothing -> errorHandler y $ BadMethod method
+                    Nothing -> errorHandler $ BadMethod method
                     Just h' -> h'
     let eurl' = either (const Nothing) Just eurl
-    let eh er = runHandler (errorHandler y er) render eurl' id y id
+    let eh er = runHandler (errorHandler er) render eurl' id y id
     let ya = runHandler h render eurl' id y id
     (s, hs, ct, c, sessionFinal) <- unYesodApp ya eh rr types
     let sessionVal = encodeSession key' exp' host sessionFinal

Yesod/Yesod.hs

@@ -69,11 +69,8 @@ class Yesod a where
     clientSessionDuration = const 120
 
     -- | Output error response pages.
-    errorHandler :: Yesod y
+    errorHandler :: ErrorResponse -> GHandler sub a ChooseRep
-                 => a
+    errorHandler = defaultErrorHandler
-                 -> ErrorResponse
-                 -> Handler y ChooseRep
-    errorHandler _ = defaultErrorHandler
 
     -- | Applies some form of layout to the contents of a page.
     defaultLayout :: PageContent (Routes a) -> GHandler sub a Content
@@ -167,9 +164,7 @@ applyLayout' :: Yesod master
 applyLayout' s = fmap chooseRep . applyLayout s mempty
 
 -- | The default error handler for 'errorHandler'.
-defaultErrorHandler :: Yesod y
+defaultErrorHandler :: Yesod y => ErrorResponse -> GHandler sub y ChooseRep
-                    => ErrorResponse
-                    -> Handler y ChooseRep
 defaultErrorHandler NotFound = do
     r <- waiRequest
     applyLayout' "Not Found" $ [$hamlet|