diff --git a/yesod-core/Yesod/Core/Types.hs b/yesod-core/Yesod/Core/Types.hs
index f0a8f93b..c7799b7c 100644
--- a/yesod-core/Yesod/Core/Types.hs
+++ b/yesod-core/Yesod/Core/Types.hs
@@ -73,7 +73,7 @@ newtype SessionBackend = SessionBackend
                     -> IO (SessionMap, SaveSession) -- ^ Return the session data and a function to save the session
     }
 
-data SessionCookie = SessionCookie (Either UTCTime ByteString) ByteString SessionMap
+data SessionCookie = SessionCookie !(Either UTCTime ByteString) !ByteString !SessionMap
     deriving (Show, Read)
 instance Serialize SessionCookie where
     put (SessionCookie a b c) = do
@@ -151,13 +151,13 @@ data Approot master = ApprootRelative -- ^ No application root.
 
 type ResolvedApproot = Text
 
-data AuthResult = Authorized | AuthenticationRequired | Unauthorized Text
+data AuthResult = Authorized | AuthenticationRequired | Unauthorized !Text
     deriving (Eq, Show, Read)
 
 data ScriptLoadPosition master
     = BottomOfBody
     | BottomOfHeadBlocking
-    | BottomOfHeadAsync (BottomOfHeadAsync master)
+    | BottomOfHeadAsync !(BottomOfHeadAsync master)
 
 type BottomOfHeadAsync master
        = [Text] -- ^ urls to load asynchronously
@@ -170,7 +170,7 @@ type Texts = [Text]
 newtype WaiSubsite = WaiSubsite { runWaiSubsite :: W.Application }
 
 -- | Like 'WaiSubsite', but applies parent site's middleware and isAuthorized.
--- 
+--
 -- @since 1.4.34
 newtype WaiSubsiteWithAuth = WaiSubsiteWithAuth { runWaiSubsiteWithAuth :: W.Application }
 
@@ -201,7 +201,7 @@ data YesodRunnerEnv site = YesodRunnerEnv
     , yreSessionBackend :: !(Maybe SessionBackend)
     , yreGen            :: !(IO Int)
     -- ^ Generate a random number
-    , yreGetMaxExpires  :: IO Text
+    , yreGetMaxExpires  :: !(IO Text)
     }
 
 data YesodSubRunnerEnv sub parent parentMonad = YesodSubRunnerEnv
@@ -228,12 +228,12 @@ type instance MonadRoute IO = ()
 type instance MonadRoute (HandlerT site m) = (Route site)
 
 data GHState = GHState
-    { ghsSession :: SessionMap
-    , ghsRBC     :: Maybe RequestBodyContents
-    , ghsIdent   :: Int
-    , ghsCache   :: TypeMap
-    , ghsCacheBy :: KeyedTypeMap
-    , ghsHeaders :: Endo [Header]
+    { ghsSession :: !SessionMap
+    , ghsRBC     :: !(Maybe RequestBodyContents)
+    , ghsIdent   :: !Int
+    , ghsCache   :: !TypeMap
+    , ghsCacheBy :: !KeyedTypeMap
+    , ghsHeaders :: !(Endo [Header])
     }
 
 -- | An extension of the basic WAI 'W.Application' datatype to provide extra
@@ -281,9 +281,9 @@ newtype CssBuilder = CssBuilder { unCssBuilder :: TBuilder.Builder }
 --
 -- > PageContent url -> HtmlUrl url
 data PageContent url = PageContent
-    { pageTitle :: Html
-    , pageHead  :: HtmlUrl url
-    , pageBody  :: HtmlUrl url
+    { pageTitle :: !Html
+    , pageHead  :: !(HtmlUrl url)
+    , pageBody  :: !(HtmlUrl url)
     }
 
 data Content = ContentBuilder !BB.Builder !(Maybe Int) -- ^ The content and optional content length.
@@ -310,11 +310,11 @@ newtype DontFullyEvaluate a = DontFullyEvaluate { unDontFullyEvaluate :: a }
 -- | Responses to indicate some form of an error occurred.
 data ErrorResponse =
       NotFound
-    | InternalError Text
-    | InvalidArgs [Text]
+    | InternalError !Text
+    | InvalidArgs ![Text]
     | NotAuthenticated
-    | PermissionDenied Text
-    | BadMethod H.Method
+    | PermissionDenied !Text
+    | BadMethod !H.Method
     deriving (Show, Eq, Typeable, Generic)
 instance NFData ErrorResponse where
     rnf = genericRnf
@@ -322,9 +322,11 @@ instance NFData ErrorResponse where
 ----- header stuff
 -- | Headers to be added to a 'Result'.
 data Header =
-      AddCookie SetCookie
-    | DeleteCookie ByteString ByteString
-    | Header ByteString ByteString
+      AddCookie !SetCookie
+    | DeleteCookie !ByteString !ByteString
+    -- ^ name and path
+    | Header !ByteString !ByteString
+    -- ^ key and value
     deriving (Eq, Show)
 
 -- FIXME In the next major version bump, let's just add strictness annotations
@@ -335,16 +337,16 @@ instance NFData Header where
     rnf (DeleteCookie x y) = x `seq` y `seq` ()
     rnf (Header x y) = x `seq` y `seq` ()
 
-data Location url = Local url | Remote Text
+data Location url = Local !url | Remote !Text
     deriving (Show, Eq)
 
 -- | A diff list that does not directly enforce uniqueness.
 -- When creating a widget Yesod will use nub to make it unique.
 newtype UniqueList x = UniqueList ([x] -> [x])
 
-data Script url = Script { scriptLocation :: Location url, scriptAttributes :: [(Text, Text)] }
+data Script url = Script { scriptLocation :: !(Location url), scriptAttributes :: ![(Text, Text)] }
     deriving (Show, Eq)
-data Stylesheet url = Stylesheet { styleLocation :: Location url, styleAttributes :: [(Text, Text)] }
+data Stylesheet url = Stylesheet { styleLocation :: !(Location url), styleAttributes :: ![(Text, Text)] }
     deriving (Show, Eq)
 newtype Title = Title { unTitle :: Html }
 
@@ -380,13 +382,13 @@ instance Monoid (GWData a) where
 instance Semigroup (GWData a)
 
 data HandlerContents =
-      HCContent H.Status !TypedContent
-    | HCError ErrorResponse
-    | HCSendFile ContentType FilePath (Maybe FilePart)
-    | HCRedirect H.Status Text
-    | HCCreated Text
-    | HCWai W.Response
-    | HCWaiApp W.Application
+      HCContent !H.Status !TypedContent
+    | HCError !ErrorResponse
+    | HCSendFile !ContentType !FilePath !(Maybe FilePart)
+    | HCRedirect !H.Status !Text
+    | HCCreated !Text
+    | HCWai !W.Response
+    | HCWaiApp !W.Application
     deriving Typeable
 
 instance Show HandlerContents where