diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 97f40010b..a024f19a8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,6 +1,6 @@
 default:
   image:
-    name: fpco/stack-build:lts-13.21
+    name: fpco/stack-build:lts-15.0
   cache:
     paths:
       - node_modules
diff --git a/.hlint.yaml b/.hlint.yaml
index 6b2cec643..7f5b23d47 100644
--- a/.hlint.yaml
+++ b/.hlint.yaml
@@ -5,6 +5,7 @@
   - ignore: { name: "Parse error" }
   - ignore: { name: "Reduce duplication" }
   - ignore: { name: "Redundant lambda" }
+  - ignore: { name: "Redundant multi-way if" }
   - ignore: { name: "Use ||" }
   - ignore: { name: "Use &&" }
   - ignore: { name: "Use ++" }
diff --git a/ghci.sh b/ghci.sh
index 750d384b8..441f9f649 100755
--- a/ghci.sh
+++ b/ghci.sh
@@ -20,4 +20,4 @@ if [[ -d .stack-work-ghci ]]; then
     trap move-back EXIT
 fi
 
-stack ghci --flag uniworx:dev --flag uniworx:library-only --ghci-options -fobject-code ${@:-uniworx:lib}
+stack ghci --flag uniworx:dev --flag uniworx:library-only --ghci-options ${@:-uniworx:lib}
diff --git a/package.yaml b/package.yaml
index 32a5bd8df..1d643c348 100644
--- a/package.yaml
+++ b/package.yaml
@@ -120,7 +120,6 @@ dependencies:
   - lens-aeson
   - systemd
   - streaming-commons
-  - hourglass
   - unix
   - stm-delay
   - cassava
@@ -201,6 +200,8 @@ ghc-options:
   - -Wall
   - -Wmissing-home-modules
   - -Wredundant-constraints
+  - -Widentities
+  - -Wincomplete-uni-patterns
   - -fno-warn-type-defaults
   - -fno-warn-unrecognised-pragmas
   - -fno-warn-partial-type-signatures
diff --git a/src/Application.hs b/src/Application.hs
index 83a229d82..ec6220a6f 100644
--- a/src/Application.hs
+++ b/src/Application.hs
@@ -86,8 +86,6 @@ import Control.Monad.Trans.Cont (runContT, callCC)
 
 import qualified Data.Set as Set
 
-import Data.Semigroup (Min(..))
-
 import Handler.Utils.Routes (classifyHandler)
 
 -- Import all relevant handler modules here.
@@ -511,6 +509,8 @@ shutdownApp app = do
     destroyAllResources $ appConnPool app
   release . fst $ appLogger app
 
+  liftIO $ threadDelay 2e4
+
 
 ---------------------------------------------
 -- Functions for use in development with GHCi
diff --git a/src/Auth/Dummy.hs b/src/Auth/Dummy.hs
index 90f3e3cee..898349bf0 100644
--- a/src/Auth/Dummy.hs
+++ b/src/Auth/Dummy.hs
@@ -8,7 +8,6 @@ import Database.Persist.Sql (SqlBackendCanRead)
 
 import Utils.Form
 
-import Data.CaseInsensitive (CI)
 import qualified Data.CaseInsensitive as CI
 
 
@@ -22,7 +21,6 @@ dummyForm :: ( RenderMessage (HandlerSite m) FormMessage
              , RenderMessage (HandlerSite m) DummyMessage
              , YesodPersist (HandlerSite m)
              , SqlBackendCanRead (YesodPersistBackend (HandlerSite m))
-             , Button (HandlerSite m) ButtonSubmit
              , MonadHandler m
              ) => AForm m (CI Text)
 dummyForm = wFormToAForm $ do
diff --git a/src/Auth/LDAP.hs b/src/Auth/LDAP.hs
index 9db9fa7fb..feaa31c44 100644
--- a/src/Auth/LDAP.hs
+++ b/src/Auth/LDAP.hs
@@ -14,14 +14,12 @@ module Auth.LDAP
 import Import.NoFoundation
 import Network.Connection
 
-import Data.CaseInsensitive (CI)
 import qualified Data.CaseInsensitive as CI
 
 import qualified Control.Monad.Catch as Exc
 
 import Utils.Form
 
-import Ldap.Client (Ldap)
 import qualified Ldap.Client as Ldap
 
 import qualified Data.Text.Encoding as Text
diff --git a/src/Auth/PWHash.hs b/src/Auth/PWHash.hs
index 3fd716694..2812b67eb 100644
--- a/src/Auth/PWHash.hs
+++ b/src/Auth/PWHash.hs
@@ -8,7 +8,6 @@ import Database.Persist.Sql (SqlBackendCanRead)
 
 import Utils.Form
 
-import Data.CaseInsensitive (CI)
 import qualified Data.CaseInsensitive as CI
 
 import Yesod.Auth.Util.PasswordStore (verifyPasswordWith)
diff --git a/src/Cron.hs b/src/Cron.hs
index 36a063321..4cfc505ac 100644
--- a/src/Cron.hs
+++ b/src/Cron.hs
@@ -296,20 +296,21 @@ nextCronMatch tz mPrev prec now c@Cron{..} = onlyOnceWithinPrec $ case notAfter
                <*> genMatch 60 True True cdMinute cronMinute
                <*> genMatch 60 True True cdSecond cronSecond
 
-        let toGregorian' = over _1 fromIntegral . over _2 fromIntegral . over _3 fromIntegral . toGregorian
+        let toGregorian' :: Day -> (Natural, Natural, Natural)
+            toGregorian' = over _1 fromIntegral . over _2 fromIntegral . over _3 fromIntegral . toGregorian
         (mCronYear, mCronMonth, mCronDayOfMonth) <- if
             | Just (year, month, dayOfMonth) <- mCronGregorianDate
               -> return (year, month, dayOfMonth)
-            | Just (weekYear, week, dayOfWeek) <- mCronWeekDate
-              -> return . toGregorian' $ fromWeekDate (fromIntegral weekYear) (fromIntegral week) (fromIntegral dayOfWeek)
+            | Just (weekYear, week, dow) <- mCronWeekDate
+              -> return . toGregorian' $ fromWeekDate (fromIntegral weekYear) (fromIntegral week) (fromIntegral dow)
             | Just (year, dayOfYear) <- mCronOrdinalDate
               -> maybeToList . fmap toGregorian' $ fromOrdinalDateValid (fromIntegral year) (fromIntegral dayOfYear)
-            | Just (weekYear, month, weekOfMonth, dayOfWeek) <- mCronWeekOfMonthDate
+            | Just (weekYear, month, weekOfMonth, dow) <- mCronWeekOfMonthDate
               -> do
                    year <- genMatch 400 False True cdYear cronYear
                    day <- genMatch 31 True False cdDayOfMonth cronDayOfMonth
                    jDay <- maybeToList $ fromGregorianValid (fromIntegral year) (fromIntegral month) (fromIntegral day)
-                   guard $ consistentCronDate (toCronDate localRef{ localDay = jDay }) { cdWeekYear = weekYear, cdMonth = month, cdWeekOfMonth = weekOfMonth, cdDayOfWeek = dayOfWeek }
+                   guard $ consistentCronDate (toCronDate localRef{ localDay = jDay }) { cdWeekYear = weekYear, cdMonth = month, cdWeekOfMonth = weekOfMonth, cdDayOfWeek = dow }
                    return (year, month, day)
             | otherwise
               -> fmap toGregorian' [localDay localRef, succ $ localDay localRef]
@@ -329,8 +330,8 @@ nextCronMatch tz mPrev prec now c@Cron{..} = onlyOnceWithinPrec $ case notAfter
               -> return . over _1 fromIntegral . over _2 fromIntegral . over _3 fromIntegral $ toWeekDate julDay
 
         mCronWeekOfMonth <- if
-            | Just (weekYear, month, weekOfMonth, dayOfWeek) <- mCronWeekOfMonthDate
-              -> weekOfMonth <$ guard (weekYear == mCronWeekYear && month == mCronMonth && dayOfWeek == mCronDayOfWeek)
+            | Just (weekYear, month, weekOfMonth, dow) <- mCronWeekOfMonthDate
+              -> weekOfMonth <$ guard (weekYear == mCronWeekYear && month == mCronMonth && dow == mCronDayOfWeek)
             | otherwise
               -> genMatch 5 True False cdWeekOfMonth cronWeekOfMonth
 
diff --git a/src/Cron/Types.hs b/src/Cron/Types.hs
index 576796038..00eec5047 100644
--- a/src/Cron/Types.hs
+++ b/src/Cron/Types.hs
@@ -15,7 +15,6 @@ import Data.Time
 
 import Numeric.Natural
 
-import Data.HashMap.Strict (HashMap)
 import qualified Data.Set as Set
   
 
diff --git a/src/Crypto/Hash/Instances.hs b/src/Crypto/Hash/Instances.hs
index 3c07f0882..ae803ae92 100644
--- a/src/Crypto/Hash/Instances.hs
+++ b/src/Crypto/Hash/Instances.hs
@@ -11,15 +11,12 @@ import Database.Persist
 import Database.Persist.Sql
 
 import Data.ByteArray (convert)
-import Data.ByteArray.Encoding
-
-import qualified Data.ByteString.Char8 as CBS
 
 import Web.PathPieces
 import Web.HttpApiData
 import Data.Aeson as Aeson
 
-import Text.Read as Read
+import Control.Monad.Fail
 
 
 instance HashAlgorithm hash => PersistField (Digest hash) where
@@ -31,12 +28,6 @@ instance HashAlgorithm hash => PersistField (Digest hash) where
 instance HashAlgorithm hash => PersistFieldSql (Digest hash) where
   sqlType _ = SqlBlob 
 
-instance HashAlgorithm hash => Read (Digest hash) where
-  readPrec = do
-    str <- replicateM (2 * hashDigestSize (error "Value of type hash forced" :: hash)) Read.get
-    bs <- either fail return . convertFromBase Base16 $ CBS.pack str
-    maybe (fail "Could not convert digestFromByteString") return $ digestFromByteString (bs :: ByteString)
-
 instance HashAlgorithm hash => PathPiece (Digest hash) where
   toPathPiece = showToPathPiece
   fromPathPiece = readFromPathPiece
diff --git a/src/CryptoID.hs b/src/CryptoID.hs
index efcc099ca..c7b8618cc 100644
--- a/src/CryptoID.hs
+++ b/src/CryptoID.hs
@@ -21,10 +21,9 @@ import System.FilePath.Cryptographic.ImplicitNamespace
 
 import qualified Data.Text as Text
 
-import           Data.CaseInsensitive   (CI)
 import qualified Data.CaseInsensitive as CI
 
-import Data.Aeson (ToJSON(..), ToJSONKey(..), ToJSONKeyFunction(..), FromJSON(..), FromJSONKey(..), FromJSONKeyFunction(..), Value(..), withText)
+import Data.Aeson (withText)
 import Data.Aeson.Encoding (text)
 
 import Text.Blaze (ToMarkup(..))
diff --git a/src/CryptoID/TH.hs b/src/CryptoID/TH.hs
index 85f73dc03..0e1065a27 100644
--- a/src/CryptoID/TH.hs
+++ b/src/CryptoID/TH.hs
@@ -9,7 +9,6 @@ import Data.UUID.Types (UUID)
 import Data.Binary.SerializationLength
 
 import Data.CaseInsensitive (CI)
-import System.FilePath (FilePath)
 
 import Data.Binary (Binary)
 import qualified Data.Binary as Binary
diff --git a/src/Data/Aeson/Types/Instances.hs b/src/Data/Aeson/Types/Instances.hs
index 4e87d05a9..10d4c106e 100644
--- a/src/Data/Aeson/Types/Instances.hs
+++ b/src/Data/Aeson/Types/Instances.hs
@@ -16,6 +16,8 @@ import Data.Vector.Instances ()
 
 import Model.Types.TH.JSON (derivePersistFieldJSON)
 
+import Control.Monad.Fail
+
 
 instance MonadThrow Parser where
   throwM = fail . show
diff --git a/src/Data/Bool/Instances.hs b/src/Data/Bool/Instances.hs
index d5eb7a2e0..6ea955599 100644
--- a/src/Data/Bool/Instances.hs
+++ b/src/Data/Bool/Instances.hs
@@ -12,6 +12,8 @@ import Data.CaseInsensitive.Instances ()
 
 import qualified Data.Text as Text
 
+import Control.Monad.Fail
+
 
 instance Csv.ToField Bool where
   toField True = "t"
diff --git a/src/Data/CaseInsensitive/Instances.hs b/src/Data/CaseInsensitive/Instances.hs
index f218308f5..77f626338 100644
--- a/src/Data/CaseInsensitive/Instances.hs
+++ b/src/Data/CaseInsensitive/Instances.hs
@@ -16,12 +16,11 @@ import Database.Persist.Sql
 import Text.Blaze (ToMarkup(..))
 import Text.Shakespeare.Text (ToText(..))
 
-import Data.Text (Text)
 import qualified Data.Text.Encoding as Text
 
 import Language.Haskell.TH.Syntax (Lift(..))
 
-import Data.Aeson (ToJSON(..), FromJSON(..), ToJSONKey(..), FromJSONKey(..), ToJSONKeyFunction(..))
+import Data.Aeson (ToJSONKey(..), FromJSONKey(..), ToJSONKeyFunction(..))
 
 import qualified Database.Esqueleto as E
 
diff --git a/src/Data/Encoding/Instances.hs b/src/Data/Encoding/Instances.hs
index ee73551fb..d9bf3748d 100644
--- a/src/Data/Encoding/Instances.hs
+++ b/src/Data/Encoding/Instances.hs
@@ -6,13 +6,14 @@ module Data.Encoding.Instances
 
 import ClassyPrelude
 import Utils.PathPiece
-import Data.String (IsString(..))
 import Text.Read
 
 import Web.PathPieces
 
 import Data.Encoding
 
+import Control.Monad.Fail
+
 
 instance PathPiece DynEncoding where
   toPathPiece = showToPathPiece
diff --git a/src/Data/HashMap/Strict/Instances.hs b/src/Data/HashMap/Strict/Instances.hs
index 7d56f03a8..daa36c68a 100644
--- a/src/Data/HashMap/Strict/Instances.hs
+++ b/src/Data/HashMap/Strict/Instances.hs
@@ -7,7 +7,6 @@ module Data.HashMap.Strict.Instances
 import ClassyPrelude
 
 import Data.Binary (Binary(..))
-import Data.HashMap.Strict (HashMap)
 import qualified Data.HashMap.Strict as HashMap
 
 
diff --git a/src/Data/HashSet/Instances.hs b/src/Data/HashSet/Instances.hs
index 3fc16cd43..320ac8940 100644
--- a/src/Data/HashSet/Instances.hs
+++ b/src/Data/HashSet/Instances.hs
@@ -6,7 +6,6 @@ module Data.HashSet.Instances
 
 import ClassyPrelude
 
-import Data.HashSet (HashSet)
 import qualified Data.HashSet as HashSet
 
 import Data.Binary (Binary(..))
diff --git a/src/Data/NonNull/Instances.hs b/src/Data/NonNull/Instances.hs
index 55981d6ff..8c7c3dca8 100644
--- a/src/Data/NonNull/Instances.hs
+++ b/src/Data/NonNull/Instances.hs
@@ -11,6 +11,8 @@ import Data.Aeson
 import Data.Binary (Binary)
 import qualified Data.Binary as Binary
 
+import Control.Monad.Fail
+
 
 instance ToJSON a => ToJSON (NonNull a) where
   toJSON = toJSON . toNullable
diff --git a/src/Data/Set/Instances.hs b/src/Data/Set/Instances.hs
index 9dc1c48cd..5fe431d92 100644
--- a/src/Data/Set/Instances.hs
+++ b/src/Data/Set/Instances.hs
@@ -6,7 +6,6 @@ module Data.Set.Instances
 
 import ClassyPrelude
 
-import Data.Set (Set)
 import qualified Data.Set as Set
 
 
diff --git a/src/Data/Time/Calendar/Instances.hs b/src/Data/Time/Calendar/Instances.hs
index 395f455f8..d5dd127ed 100644
--- a/src/Data/Time/Calendar/Instances.hs
+++ b/src/Data/Time/Calendar/Instances.hs
@@ -7,12 +7,16 @@ module Data.Time.Calendar.Instances
 
 import ClassyPrelude
 import Data.Binary (Binary)
-import qualified Data.Binary as Binary
+
+import Data.Time.Calendar
+
+import Data.Universe
 
 
 deriving newtype instance Hashable Day
+deriving newtype instance Binary Day
 
-instance Binary Day where
-  get = ModifiedJulianDay <$> Binary.get
-  put = Binary.put . toModifiedJulianDay
-
+deriving instance Ord DayOfWeek
+instance Universe DayOfWeek where
+  universe = [Monday .. Sunday]
+instance Finite DayOfWeek
diff --git a/src/Data/Universe/Instances/Reverse/JSON.hs b/src/Data/Universe/Instances/Reverse/JSON.hs
index 7c8dbb3ed..8aed56f14 100644
--- a/src/Data/Universe/Instances/Reverse/JSON.hs
+++ b/src/Data/Universe/Instances/Reverse/JSON.hs
@@ -15,6 +15,8 @@ import Data.HashMap.Strict ((!))
 
 import Data.Universe
 
+import Control.Monad.Fail
+
 
 instance (Eq a, Hashable a, Finite a, ToJSON b, ToJSONKey a) => ToJSON (a -> b) where
   toJSON f = toJSON $ HashMap.fromList [(k, f k) | k <- universeF]
diff --git a/src/Data/Universe/TH.hs b/src/Data/Universe/TH.hs
index 1dd097e9f..192182320 100644
--- a/src/Data/Universe/TH.hs
+++ b/src/Data/Universe/TH.hs
@@ -17,12 +17,21 @@ import Control.Monad (unless)
 import Data.List (elemIndex)
 
 
+-- | Get type var bind name
+--
+-- Stolen from https://hackage.haskell.org/package/template-haskell-util-0.1.1.0
+getTVBName :: TyVarBndr -> Name
+getTVBName (PlainTV  name  ) = name
+getTVBName (KindedTV name _) = name
+  
+
+
 finiteEnum :: Name -> DecsQ
 -- ^ Declare generic `Enum`- and `Bounded`-Instances given `Finite`- and `Eq`-Instances
 finiteEnum tName = do
   DatatypeInfo{..} <- reifyDatatype tName
 
-  let datatype = foldl appT (conT datatypeName) $ map pure datatypeVars
+  let datatype = foldl appT (conT datatypeName) $ map (varT . getTVBName) datatypeVars
       tUniverse = [e|universeF :: [$(datatype)]|]
   
   [d|
@@ -48,14 +57,14 @@ deriveFinite tName = fmap concat . sequence $
   [ deriveUniverse' [e|concat|] [e|universeF|] tName
   , do
       DatatypeInfo{..} <- reifyDatatype tName
-      [d|instance Finite $(foldl appT (conT datatypeName) $ map pure datatypeVars)|]
+      [d|instance Finite $(foldl appT (conT datatypeName) $ map (varT . getTVBName) datatypeVars)|]
   ]
 
 deriveUniverse' :: ExpQ -> ExpQ -> Name -> DecsQ
 deriveUniverse' interleaveExp universeExp tName = do
   DatatypeInfo{..} <- reifyDatatype tName
 
-  let datatype = foldl appT (conT datatypeName) $ map pure datatypeVars
+  let datatype = foldl appT (conT datatypeName) $ map (varT . getTVBName) datatypeVars
       consUniverse ConstructorInfo{..} = do
         unless (null constructorVars) $
           fail "Constructors with variables no supported"
diff --git a/src/Data/Vector/Instances.hs b/src/Data/Vector/Instances.hs
index 953130328..ecb64bd69 100644
--- a/src/Data/Vector/Instances.hs
+++ b/src/Data/Vector/Instances.hs
@@ -6,7 +6,6 @@ module Data.Vector.Instances
 
 import ClassyPrelude
 
-import Data.Vector (Vector)
 import qualified Data.Vector as Vector
 
 import Data.Binary (Binary)
diff --git a/src/Database/Persist/Class/Instances.hs b/src/Database/Persist/Class/Instances.hs
index 193ea1f16..a44e6071b 100644
--- a/src/Database/Persist/Class/Instances.hs
+++ b/src/Database/Persist/Class/Instances.hs
@@ -8,7 +8,6 @@ module Database.Persist.Class.Instances
 import ClassyPrelude
 
 import Database.Persist.Class
-import Database.Persist.Types (HaskellName, DBName, PersistValue)
 import Database.Persist.Types.Instances ()
 import Database.Persist.Sql
 
@@ -19,6 +18,8 @@ import qualified Data.Map as Map
 
 import Data.Aeson (ToJSONKey, FromJSONKey)
 
+import Control.Monad.Fail
+
 
 instance PersistEntity record => Hashable (Key record) where
   hashWithSalt s = hashWithSalt s . toPersistValue
diff --git a/src/Foundation.hs b/src/Foundation.hs
index d79b5a45e..5c39d6b86 100644
--- a/src/Foundation.hs
+++ b/src/Foundation.hs
@@ -2,7 +2,7 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# LANGUAGE OverloadedLabels #-}
-{-# OPTIONS_GHC -fno-warn-orphans #-} -- MonadCrypto
+{-# OPTIONS_GHC -fno-warn-orphans -fno-warn-incomplete-uni-patterns #-} -- MonadCrypto
 
 module Foundation
   ( module Foundation
@@ -29,43 +29,36 @@ import qualified Yesod.Core.Unsafe as Unsafe
 import qualified Data.CaseInsensitive as CI
 
 import Data.ByteArray (convert)
-import Crypto.Hash (Digest, SHAKE256, SHAKE128)
+import Crypto.Hash (SHAKE256, SHAKE128)
 import Crypto.Hash.Conduit (sinkHash)
 import qualified Data.UUID as UUID
 import qualified Data.Binary as Binary
 
 import qualified Data.ByteString.Base64.URL as Base64 (encode)
 
-import Data.ByteString (ByteString)
 import qualified Data.ByteString.Lazy as Lazy.ByteString
 import qualified Data.ByteString as ByteString
 
 import qualified Data.Text as Text
 import qualified Data.Text.Encoding as Text
 
-import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Map (Map, (!?))
+import Data.Map ((!?))
 import qualified Data.Map as Map
 import qualified Data.HashSet as HashSet
 import qualified Data.List.NonEmpty as NonEmpty
 
-import Data.List (nubBy, (!!), findIndex, inits)
+import Data.List ((!!), findIndex, inits)
 import qualified Data.List as List
 
 import Web.Cookie
 
-import Data.Monoid (Any(..))
-
 import Data.Conduit.List (sourceList)
 
 import qualified Database.Esqueleto as E
 import qualified Database.Esqueleto.Utils as E
 
 import Control.Monad.Except (MonadError(..), ExceptT)
-import Control.Monad.Trans.Maybe (MaybeT(..))
-import Control.Monad.Trans.Reader (runReader, mapReaderT)
-import Control.Monad.Trans.Writer (WriterT(..), runWriterT)
 import Control.Monad.Trans.State (execStateT)
 import Control.Monad.Writer.Class (MonadWriter(..))
 import Control.Monad.Memo.Class (MonadMemo(..), for4)
@@ -82,7 +75,6 @@ import Utils.Form
 import Utils.Sheet
 import Utils.SystemMessage
 
-import Text.Shakespeare.Text (st)
 import Text.Cassius (cassiusFile)
 
 import Yesod.Form.I18n.German
@@ -1121,12 +1113,12 @@ tagAccessPredicate AuthCapacity = APDB $ \_ route _ -> case route of
   CTutorialR tid ssh csh tutn _ -> maybeT (unauthorizedI MsgTutorialNoCapacity) $ do
     cid <- $cachedHereBinary (tid, ssh, csh) . MaybeT . getKeyBy $ TermSchoolCourseShort tid ssh csh
     Entity tutId Tutorial{..} <- $cachedHereBinary (cid, tutn) . MaybeT . getBy $ UniqueTutorial cid tutn
-    registered <- $cachedHereBinary tutId . lift $ fromIntegral <$> count [ TutorialParticipantTutorial ==. tutId ]
+    registered <- $cachedHereBinary tutId . lift $ count [ TutorialParticipantTutorial ==. tutId ]
     guard $ NTop tutorialCapacity > NTop (Just registered)
     return Authorized
   CourseR tid ssh csh _ -> maybeT (unauthorizedI MsgCourseNoCapacity) $ do
     Entity cid Course{..} <- $cachedHereBinary (tid, ssh, csh) . MaybeT . getBy $ TermSchoolCourseShort tid ssh csh
-    registered <- $cachedHereBinary cid . lift $ fromIntegral <$> count [ CourseParticipantCourse ==. cid ]
+    registered <- $cachedHereBinary cid . lift $ count [ CourseParticipantCourse ==. cid ]
     guard $ NTop courseCapacity > NTop (Just registered)
     return Authorized
   r -> $unsupportedAuthPredicate AuthCapacity r
@@ -1298,7 +1290,7 @@ routeAuthTags = fmap (PredDNF . Set.mapMonotonic impureNonNull) . ofoldM partiti
       | otherwise
         = Left $ InvalidAuthTag t
 
-evalAuthTags :: forall m. (MonadAP m, MonadLogger m) => AuthTagActive -> AuthDNF -> Maybe (AuthId UniWorX) -> Route UniWorX -> Bool -> WriterT (Set AuthTag) m AuthResult
+evalAuthTags :: forall m. MonadAP m => AuthTagActive -> AuthDNF -> Maybe (AuthId UniWorX) -> Route UniWorX -> Bool -> WriterT (Set AuthTag) m AuthResult
 -- ^ `tell`s disabled predicates, identified as pivots
 evalAuthTags AuthTagActive{..} (map (Set.toList . toNullable) . Set.toList . dnfTerms -> authDNF') mAuthId route isWrite
   = do
diff --git a/src/Foundation/I18n.hs b/src/Foundation/I18n.hs
index aa7933300..b1ab71296 100644
--- a/src/Foundation/I18n.hs
+++ b/src/Foundation/I18n.hs
@@ -32,8 +32,6 @@ import qualified Data.Text as Text
 
 import Utils.Form
 
-import Text.Shakespeare.Text (st)
-
 import GHC.Exts (IsList(..))
 
 
diff --git a/src/Foundation/Type.hs b/src/Foundation/Type.hs
index 5b63b9080..f6292c4f9 100644
--- a/src/Foundation/Type.hs
+++ b/src/Foundation/Type.hs
@@ -13,8 +13,6 @@ import Jobs.Types
 
 import Yesod.Core.Types (Logger)
 
-import Data.Set (Set)
-
 import qualified Crypto.Saltine.Core.SecretBox as SecretBox
 import qualified Jose.Jwk as Jose
 
diff --git a/src/Handler/Admin/StudyFeatures.hs b/src/Handler/Admin/StudyFeatures.hs
index 6fe21e14d..f07bdc979 100644
--- a/src/Handler/Admin/StudyFeatures.hs
+++ b/src/Handler/Admin/StudyFeatures.hs
@@ -250,7 +250,7 @@ postAdminFeaturesR = do
                   -> DBRow r 
                   -> DBCell (MForm (HandlerFor UniWorX)) (FormResult (DBFormResult i a (DBRow r)))
     textInputCell lensRes lensDefault lensIndex = formCell id (return . view lensIndex)
-      (\row _mkUnique -> (\(res,fieldView) -> (set lensRes . assertM (not . Text.null) <$> res, fvInput fieldView))
+      (\row _mkUnique -> bimap (fmap $ set lensRes . assertM (not . Text.null)) fvInput
         <$> mopt (textField & cfStrip) "" (Just $ row ^. lensDefault)
       )
   
@@ -261,7 +261,7 @@ postAdminFeaturesR = do
                  -> DBRow r 
                  -> DBCell (MForm (HandlerFor UniWorX)) (FormResult (DBFormResult i a (DBRow r))) 
     checkboxCell lensRes lensDefault lensIndex = formCell id (return . view lensIndex)
-      ( \row _mkUnique -> (\(res, fieldView) -> (set lensRes <$> res, fvInput fieldView))
+      ( \row _mkUnique -> bimap (fmap $ set lensRes) fvInput
         <$> mpopt checkBoxField "" (Just $ row ^. lensDefault)
       )
 
@@ -283,7 +283,7 @@ postAdminFeaturesR = do
                 -> DBRow r
                 -> DBCell (MForm (HandlerFor UniWorX)) (FormResult (DBFormResult i a (DBRow r)))
     parentsCell lensRes lensDefault lensIndex = formCell id (return . view lensIndex)
-      ( \row mkUnique -> (\(res, fieldView) -> (set lensRes . Set.fromList <$> res, fvInput fieldView))
+      ( \row mkUnique -> bimap (fmap $ set lensRes . Set.fromList) fvInput
         <$> massInputList
               (intField & isoField (from _StudyTermsId))
               (const "")
@@ -302,7 +302,7 @@ postAdminFeaturesR = do
                -> DBRow r
                -> DBCell (MForm (HandlerFor UniWorX)) (FormResult (DBFormResult i a (DBRow r)))
     degreeCell lensRes lensDefault lensIndex = formCell id (return . view lensIndex)
-      ( \row _mkUnique -> (\(res, fieldView) -> (set lensRes <$> res, fvInput fieldView))
+      ( \row _mkUnique -> bimap (fmap $ set lensRes) fvInput
         <$> mopt degreeField "" (Just $ row ^. lensDefault)
       )
   
@@ -313,7 +313,7 @@ postAdminFeaturesR = do
                   -> DBRow r
                   -> DBCell (MForm (HandlerFor UniWorX)) (FormResult (DBFormResult i a (DBRow r)))
     fieldTypeCell lensRes lensDefault lensIndex = formCell id (return . view lensIndex)
-      ( \row _mkUnique -> (\(res, fieldView) -> (set lensRes <$> res, fvInput fieldView))
+      ( \row _mkUnique -> bimap (fmap $ set lensRes) fvInput
         <$> mopt (selectField optionsFinite) "" (Just $ row ^. lensDefault)
       )
 
diff --git a/src/Handler/Admin/Test.hs b/src/Handler/Admin/Test.hs
index b08f07dff..d2eedd9b6 100644
--- a/src/Handler/Admin/Test.hs
+++ b/src/Handler/Admin/Test.hs
@@ -7,16 +7,12 @@ import Import
 import Handler.Utils
 import Jobs
 
-import Control.Monad.Trans.Writer (mapWriterT)
-
 import Data.Char (isDigit)
 import qualified Data.Text as Text
 
 import qualified Data.Set as Set
 import qualified Data.Map as Map
 
-import Database.Persist.Sql (fromSqlKey)
-
 
 -- BEGIN - Buttons needed only here
 data ButtonCreate = CreateMath | CreateInf  -- Dummy for Example
@@ -158,7 +154,7 @@ postAdminTestR = do
     mkAddForm 0 0 nudge submitBtn = Just $ \csrf -> do
       (addRes, addView) <- mpreq textField ("" & addName (nudge "text")) Nothing -- Any old field; for demonstration
       let addRes' = fromMaybe 0 . readMay . Text.filter isDigit <$> addRes -- Do something semi-interesting on the result of the @textField@ to demonstrate that further processing can be done
-          addRes'' = addRes' <&> \dat prev -> FormSuccess (Map.singleton (maybe 0 succ . fmap fst $ Map.lookupMax prev) dat) -- Construct the callback to determine new cell positions and data within @FormResult@ as required, nested @FormResult@ allows aborting the add depending on previous data
+          addRes'' = addRes' <&> \dat prev -> FormSuccess (Map.singleton (maybe 0 (succ . fst) $ Map.lookupMax prev) dat) -- Construct the callback to determine new cell positions and data within @FormResult@ as required, nested @FormResult@ allows aborting the add depending on previous data
       return (addRes'', toWidget csrf >> fvInput addView >> fvInput submitBtn)
     mkAddForm _pos _dim _ _ = error "Dimension and Position is always 0 for our 1-dimensional form"
 
diff --git a/src/Handler/Corrections.hs b/src/Handler/Corrections.hs
index 9fb3215e8..40abe8d14 100644
--- a/src/Handler/Corrections.hs
+++ b/src/Handler/Corrections.hs
@@ -11,18 +11,13 @@ import Handler.Utils.SheetType
 import Handler.Utils.Delete
 -- import Handler.Utils.Zip
 
-import Data.List as List (nub, foldl, foldr)
-import Data.Set (Set)
+import Data.List as List (foldl, foldr)
 import qualified Data.Set as Set
-import Data.Map.Strict (Map, (!))
+import Data.Map.Strict ((!))
 import qualified Data.Map.Strict as Map
 
 import qualified Data.Text as Text
 import qualified Data.CaseInsensitive as CI
-import Data.CaseInsensitive (CI)
-
-import Data.Semigroup (Sum(..))
-import Data.Monoid (All(..))
 
 -- import Data.Time
 -- import Data.Function ((&))
@@ -49,14 +44,8 @@ import Database.Persist.Sql (updateWhereCount)
 
 import Data.List (genericLength)
 
-import Control.Monad.Trans.Writer (WriterT(..), runWriter, execWriterT)
-import Control.Monad.Trans.Reader (mapReaderT)
-
-import Control.Monad.Trans.State (State, runState)
 import qualified Control.Monad.State.Class as State
 
-import Data.Foldable (foldrM)
-
 import qualified Data.Conduit.List as C
 
 
diff --git a/src/Handler/Course/Application/Files.hs b/src/Handler/Course/Application/Files.hs
index b6d3b77a5..124ec688f 100644
--- a/src/Handler/Course/Application/Files.hs
+++ b/src/Handler/Course/Application/Files.hs
@@ -8,8 +8,6 @@ module Handler.Course.Application.Files
 import Import
 import Handler.Utils
 
-import System.FilePath (addExtension, (</>))
-
 import qualified Data.Conduit.List as C
 
 import qualified Database.Esqueleto as E
diff --git a/src/Handler/Course/Application/List.hs b/src/Handler/Course/Application/List.hs
index b4e5b7f51..a59370ac0 100644
--- a/src/Handler/Course/Application/List.hs
+++ b/src/Handler/Course/Application/List.hs
@@ -18,7 +18,6 @@ import qualified Data.Csv as Csv
 import qualified Data.Text as Text
 import qualified Data.Text.Lens as Text
 
-import Data.CaseInsensitive (CI)
 import qualified Data.CaseInsensitive as CI
 
 import qualified Data.Map as Map
diff --git a/src/Handler/Course/Edit.hs b/src/Handler/Course/Edit.hs
index 9c4805798..8707c568b 100644
--- a/src/Handler/Course/Edit.hs
+++ b/src/Handler/Course/Edit.hs
@@ -10,14 +10,12 @@ import Handler.Utils
 import Handler.Utils.Invitations
 
 import qualified Data.CaseInsensitive as CI
-import Data.Function ((&))
 
 import Data.Maybe (fromJust)
 import qualified Data.Set as Set
 import Data.Map ((!))
 import qualified Data.Map as Map
 
-import Control.Monad.Trans.Writer (execWriterT)
 import qualified Control.Monad.State.Class as State
 
 import qualified Database.Esqueleto as E
diff --git a/src/Handler/Course/LecturerInvite.hs b/src/Handler/Course/LecturerInvite.hs
index 9d52eeede..0e410a597 100644
--- a/src/Handler/Course/LecturerInvite.hs
+++ b/src/Handler/Course/LecturerInvite.hs
@@ -12,7 +12,6 @@ import Utils.Form
 import Handler.Utils.Invitations
 
 import qualified Data.CaseInsensitive as CI
-import Data.Function ((&))
 
 import Data.Aeson hiding (Result(..))
 
@@ -74,6 +73,7 @@ lecturerInvitationConfig = InvitationConfig{..}
       Just lType -> aforced (selectField optionsFinite) lFs lType
       where
         toJunction jLecturerType = (JunctionLecturer{..}, ())
+        lFs :: FieldSettings UniWorX
         lFs = fslI MsgLecturerType & setTooltip MsgCourseLecturerRightsIdentical
     invitationInsertHook _ _ _ _ _ = id
     invitationSuccessMsg (Entity _ Course{..}) (Entity _ Lecturer{..}) = do
diff --git a/src/Handler/Course/List.hs b/src/Handler/Course/List.hs
index 10192bdd5..cc499243b 100644
--- a/src/Handler/Course/List.hs
+++ b/src/Handler/Course/List.hs
@@ -14,8 +14,6 @@ import Utils.Form
 -- import Utils.DB
 import Handler.Utils hiding (colSchoolShort)
 
-import Data.Function ((&))
-
 import qualified Data.Set as Set
 import qualified Data.Map as Map
 
diff --git a/src/Handler/Course/News/Show.hs b/src/Handler/Course/News/Show.hs
index 9fb4f81b1..5a9298468 100644
--- a/src/Handler/Course/News/Show.hs
+++ b/src/Handler/Course/News/Show.hs
@@ -5,6 +5,8 @@ module Handler.Course.News.Show
 import Import
 import Handler.Utils
 
+{-# ANN module ("HLint: ignore Too strict maybe"::String) #-}
+
 
 getCNShowR :: TermId -> SchoolId -> CourseShorthand -> CryptoUUIDCourseNews -> Handler Html
 getCNShowR tid ssh csh cID = do
diff --git a/src/Handler/Course/ParticipantInvite.hs b/src/Handler/Course/ParticipantInvite.hs
index 99558d12f..cfdba213a 100644
--- a/src/Handler/Course/ParticipantInvite.hs
+++ b/src/Handler/Course/ParticipantInvite.hs
@@ -16,7 +16,6 @@ import Handler.Utils
 import Handler.Utils.Invitations
 
 import qualified Data.CaseInsensitive as CI
-import Data.Function ((&))
 
 import qualified Data.Set as Set
 
@@ -26,7 +25,6 @@ import Data.Aeson hiding (Result(..))
 
 import Text.Hamlet (ihamlet)
 
-import Control.Monad.Trans.Writer (WriterT, execWriterT)
 import Control.Monad.Except (MonadError(..))
 
 import Generics.Deriving.Monoid (memptydefault, mappenddefault)
diff --git a/src/Handler/Course/Register.hs b/src/Handler/Course/Register.hs
index 2657455e3..fe3eea1a9 100644
--- a/src/Handler/Course/Register.hs
+++ b/src/Handler/Course/Register.hs
@@ -10,8 +10,6 @@ import Import
 
 import Handler.Utils
 
-import Data.Function ((&))
-
 import qualified Data.Text as Text
 
 import qualified Data.Conduit.List as C
diff --git a/src/Handler/Course/Show.hs b/src/Handler/Course/Show.hs
index 278df79e8..e07eec99f 100644
--- a/src/Handler/Course/Show.hs
+++ b/src/Handler/Course/Show.hs
@@ -18,8 +18,6 @@ import qualified Database.Esqueleto as E
 
 import Handler.Course.Register
 
-import System.FilePath (addExtension, pathSeparator)
-
 import qualified Data.Conduit.List as C
 
 
diff --git a/src/Handler/Course/User.hs b/src/Handler/Course/User.hs
index 9b9806169..aef35f333 100644
--- a/src/Handler/Course/User.hs
+++ b/src/Handler/Course/User.hs
@@ -8,8 +8,6 @@ import Utils.Form
 import Handler.Utils
 import Database.Esqueleto.Utils.TH
 
-import Data.Function ((&))
-
 import qualified Database.Esqueleto as E
 
 import Text.Blaze.Html.Renderer.Text (renderHtml)
diff --git a/src/Handler/Course/Users.hs b/src/Handler/Course/Users.hs
index 3ba3d9801..a3a0ee89b 100644
--- a/src/Handler/Course/Users.hs
+++ b/src/Handler/Course/Users.hs
@@ -16,8 +16,6 @@ import Database.Esqueleto.Utils.TH
 
 import Handler.Course.Register (deregisterParticipant)
 
-import Data.Function ((&))
-
 import qualified Data.Set as Set
 import qualified Data.Map as Map
 import qualified Data.Text as Text
diff --git a/src/Handler/CryptoIDDispatch.hs b/src/Handler/CryptoIDDispatch.hs
index 9270fffe2..66c152c9f 100644
--- a/src/Handler/CryptoIDDispatch.hs
+++ b/src/Handler/CryptoIDDispatch.hs
@@ -7,11 +7,10 @@ import Import
 
 import qualified Data.Text as Text
 
-import Yesod.Core.Types (HandlerContents(..), ErrorResponse(..))
+import Yesod.Core.Types (HandlerContents(..))
 
 import qualified Control.Monad.Catch as E (Handler(..))
 
-import           Data.CaseInsensitive   (CI)
 import qualified Data.CaseInsensitive as CI
 
 
diff --git a/src/Handler/Exam/AddUser.hs b/src/Handler/Exam/AddUser.hs
index 9ebbc150a..feee5ddc1 100644
--- a/src/Handler/Exam/AddUser.hs
+++ b/src/Handler/Exam/AddUser.hs
@@ -13,7 +13,6 @@ import qualified Data.Set as Set
 
 import Data.Semigroup (Option(..))
   
-import Control.Monad.Trans.Writer (WriterT, execWriterT)
 import Control.Monad.Error.Class (MonadError(..))
 
 import Jobs.Queue
diff --git a/src/Handler/Exam/New.hs b/src/Handler/Exam/New.hs
index 3614dd0e0..ee30db715 100644
--- a/src/Handler/Exam/New.hs
+++ b/src/Handler/Exam/New.hs
@@ -71,8 +71,8 @@ postCExamNewR tid ssh csh = do
 
         let (invites, adds) = partitionEithers $ Set.toList efCorrectors
         insertMany_ [ ExamCorrector{..}
-                    | examCorrectorUser <- adds
-                    , let examCorrectorExam = examid
+                    | let examCorrectorExam = examid
+                    , examCorrectorUser <- adds
                     ]
         sinkInvitationsF examCorrectorInvitationConfig $ map (, examid, (InvDBDataExamCorrector, InvTokenDataExamCorrector)) invites
       return insertRes
diff --git a/src/Handler/Health.hs b/src/Handler/Health.hs
index 7cb8aa83b..72a04eee4 100644
--- a/src/Handler/Health.hs
+++ b/src/Handler/Health.hs
@@ -7,8 +7,6 @@ import qualified Data.Text.Lazy.Builder as Builder
 
 import qualified Data.UUID as UUID
 
-import Data.Semigroup (Min(..), Max(..))
-
 import qualified Data.Set as Set
 
 import Control.Concurrent.STM.Delay
diff --git a/src/Handler/Material.hs b/src/Handler/Material.hs
index 91a2f9939..bf387f85c 100644
--- a/src/Handler/Material.hs
+++ b/src/Handler/Material.hs
@@ -2,8 +2,6 @@ module Handler.Material where
 
 import Import
 
-import Data.Monoid (Any(..))
-import Data.Set (Set)
 import qualified Data.Set as Set
 -- import Data.Map (Map)
 import qualified Data.Map as Map
@@ -18,10 +16,6 @@ import Utils.Form
 import Handler.Utils
 import Handler.Utils.Delete
 
-import Control.Monad.Writer (MonadWriter(..), execWriterT)
-
-import System.FilePath (addExtension)
-
 
 data MaterialForm = MaterialForm
       { mfName         :: MaterialName
diff --git a/src/Handler/Participants.hs b/src/Handler/Participants.hs
index 146564ce1..d710903b7 100644
--- a/src/Handler/Participants.hs
+++ b/src/Handler/Participants.hs
@@ -1,4 +1,4 @@
-{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
+{-# OPTIONS_GHC -fno-warn-redundant-constraints -fno-warn-incomplete-uni-patterns #-}
 module Handler.Participants
   ( getParticipantsListR
   , getParticipantsR
diff --git a/src/Handler/Profile.hs b/src/Handler/Profile.hs
index b34ce9cb2..b2988b775 100644
--- a/src/Handler/Profile.hs
+++ b/src/Handler/Profile.hs
@@ -16,7 +16,6 @@ import Handler.Utils.Tokens
 
 -- import Colonnade hiding (fromMaybe, singleton)
 -- import Yesod.Colonnade
-import Data.Monoid (Any(..))
 import Data.Map ((!))
 import qualified Data.Map as Map
 import qualified Data.Set as Set
diff --git a/src/Handler/Sheet.hs b/src/Handler/Sheet.hs
index c54f701ef..dcc7329fd 100644
--- a/src/Handler/Sheet.hs
+++ b/src/Handler/Sheet.hs
@@ -30,31 +30,18 @@ import qualified Database.Esqueleto as E
 import qualified Database.Esqueleto.Utils as E
 -- import qualified Database.Esqueleto.Internal.Sql as E
 
-import Control.Monad.Writer (MonadWriter(..), execWriterT)
--- import Control.Monad.Trans.RWS.Lazy (RWST, local)
-
--- import qualified Text.Email.Validate as Email
-
--- import qualified Data.List as List
-
 import Control.Monad.Trans.Except (runExceptT, mapExceptT, throwE)
 
-import Data.Set (Set)
 import qualified Data.Set as Set
 import qualified Data.Map as Map
 
-import Data.Map (Map, (!))
+import Data.Map ((!))
 
-import Data.Monoid (Any(..))
-
-import Control.Monad.Random.Class (MonadRandom(..))
 import Utils.Sql
 
 import Data.Aeson hiding (Result(..))
 import Text.Hamlet (ihamlet)
 
-import System.FilePath (addExtension)
-
 import Data.Time.Clock.System (systemEpochDay)
 
 
diff --git a/src/Handler/Submission.hs b/src/Handler/Submission.hs
index 2551f6164..a89be407d 100644
--- a/src/Handler/Submission.hs
+++ b/src/Handler/Submission.hs
@@ -1,4 +1,4 @@
-{-# OPTIONS_GHC -fno-warn-orphans #-}
+{-# OPTIONS_GHC -fno-warn-orphans -fno-warn-incomplete-uni-patterns #-}
 
 module Handler.Submission where
 
@@ -17,7 +17,6 @@ import Handler.Utils.Invitations
 -- import Control.Monad.State.Class
 -- import Control.Monad.Trans.State.Strict (StateT)
 
-import Data.Monoid (Any(..))
 import Data.Maybe (fromJust)
 -- import qualified Data.Maybe
 import qualified Data.Text.Encoding as Text
@@ -30,7 +29,7 @@ import qualified Data.Conduit.List as Conduit
 
 -- import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Map (Map, (!), (!?))
+import Data.Map ((!), (!?))
 import qualified Data.Map as Map
 -- import Data.Bifunctor
 
@@ -42,8 +41,6 @@ import Text.Hamlet (ihamlet)
 -- import qualified Yesod.Colonnade as Yesod
 -- import qualified Text.Blaze.Html5.Attributes as HA
 
-import System.FilePath (addExtension)
-
 -- DEPRECATED: We always show all edits!
 -- numberOfSubmissionEditDates :: Int64
 -- numberOfSubmissionEditDates = 3 -- for debugging only, should be 1 in production.
diff --git a/src/Handler/Tutorial/Users.hs b/src/Handler/Tutorial/Users.hs
index 532c38fd6..90a0cb1d2 100644
--- a/src/Handler/Tutorial/Users.hs
+++ b/src/Handler/Tutorial/Users.hs
@@ -11,7 +11,6 @@ import Handler.Utils.Tutorial
 import Database.Persist.Sql (deleteWhereCount)
 
 import qualified Data.CaseInsensitive as CI
-import Data.Function ((&))
 
 import qualified Data.Set as Set
 import qualified Data.Map as Map
diff --git a/src/Handler/Utils.hs b/src/Handler/Utils.hs
index 07ba75a72..8ba6f99ce 100644
--- a/src/Handler/Utils.hs
+++ b/src/Handler/Utils.hs
@@ -25,8 +25,6 @@ import Handler.Utils.Widgets    as Handler.Utils
 import Handler.Utils.Database   as Handler.Utils
 import Handler.Utils.Occurrences as Handler.Utils
 
-import System.FilePath.Posix (takeFileName)
-
 import Control.Monad.Logger
 
 
diff --git a/src/Handler/Utils/Allocation.hs b/src/Handler/Utils/Allocation.hs
index 92ced534b..39246dafe 100644
--- a/src/Handler/Utils/Allocation.hs
+++ b/src/Handler/Utils/Allocation.hs
@@ -27,7 +27,6 @@ import System.Random (mkStdGen)
 import Utils.Allocation
 
 import qualified Data.Conduit.List as C
-import Data.Conduit.Lift (evalStateC)
 
 import Data.Generics.Product.Param
 
@@ -176,12 +175,14 @@ doAllocation allocId regs = do
     mField <- (courseApplicationField . entityVal =<<) . listToMaybe <$> selectList [CourseApplicationCourse ==. cid, CourseApplicationUser ==. uid, CourseApplicationAllocation ==. Just allocId] []
     void . insertUnique $ CourseParticipant cid uid now mField (Just allocId)
 
-ppMatchingLog :: ( MonoFoldable mono
+ppMatchingLog :: forall mono.
+                 ( MonoFoldable mono
                  , Element mono ~ MatchingLog UserId CourseId Natural
                  )
               => mono -> Text
 ppMatchingLog = unlines . map (tshow . pretty) . otoList
   where
+    pretty :: MatchingLog UserId CourseId Natural -> MatchingLog Int64 Int64 Natural
     pretty = over (param @1) fromSqlKey
            . over (param @2) fromSqlKey
 
diff --git a/src/Handler/Utils/Communication.hs b/src/Handler/Utils/Communication.hs
index e648530ad..197f795d5 100644
--- a/src/Handler/Utils/Communication.hs
+++ b/src/Handler/Utils/Communication.hs
@@ -11,7 +11,6 @@ import Import
 import Handler.Utils
 
 import Jobs.Queue
-import Control.Monad.Trans.Reader (mapReaderT)
 
 import qualified Database.Esqueleto as E
 import qualified Data.CaseInsensitive as CI
diff --git a/src/Handler/Utils/Csv.hs b/src/Handler/Utils/Csv.hs
index 13ea6546c..81705aa53 100644
--- a/src/Handler/Utils/Csv.hs
+++ b/src/Handler/Utils/Csv.hs
@@ -20,7 +20,6 @@ import Import hiding (Header, mapM_)
 import Data.Csv
 import Data.Csv.Conduit
 
-import Data.Function ((&))
 import Control.Monad (mapM_)
 
 -- import qualified Data.Csv.Util as Csv
@@ -75,6 +74,7 @@ decodeCsv' fromCsv' = do
       $logInfoS "decodeCsv" [st|Guessed Csv.DecodeOptions from buffer of size #{tshow (LBS.length testBuffer)}/#{tshow testBufferSize}: #{tshow decodeOptions}|]
 
       fromCsv' decodeOptions
+    testBufferSize :: Num a => a
     testBufferSize = 4096
     accumTestBuffer acc
       | LBS.length acc >= testBufferSize = return acc
diff --git a/src/Handler/Utils/DateTime.hs b/src/Handler/Utils/DateTime.hs
index 6ff98943e..64afdc7ef 100644
--- a/src/Handler/Utils/DateTime.hs
+++ b/src/Handler/Utils/DateTime.hs
@@ -24,7 +24,6 @@ import Data.Time hiding (formatTime, localTimeToUTC, utcToLocalTime, utcToZonedT
 -- import Data.Time.Clock (addUTCTime,nominalDay)
 import qualified Data.Time.Format as Time
 
-import Data.Set (Set)
 import qualified Data.Set as Set
 
 import Data.Time.Clock.System (systemEpochDay)
diff --git a/src/Handler/Utils/Delete.hs b/src/Handler/Utils/Delete.hs
index 6f758786f..a97c830ab 100644
--- a/src/Handler/Utils/Delete.hs
+++ b/src/Handler/Utils/Delete.hs
@@ -27,10 +27,11 @@ import Data.Char (isAlphaNum)
 
 import qualified Database.Esqueleto as E
 import qualified Database.Esqueleto.Internal.Sql as E (SqlSelect)
-import qualified Database.Esqueleto.Internal.Language as E (From)
 
 import Jobs.Queue
 
+{-# ANN deleteR ("HLint: ignore Use const" :: String) #-}
+
 
 data DeleteRoute record = forall tables infoExpr info. (E.SqlSelect infoExpr info, E.From tables) => DeleteRoute
   { drRecords :: Set (Key record) -- ^ Records to be deleted
diff --git a/src/Handler/Utils/Exam.hs b/src/Handler/Utils/Exam.hs
index 129d11b7e..cac40a135 100644
--- a/src/Handler/Utils/Exam.hs
+++ b/src/Handler/Utils/Exam.hs
@@ -1,4 +1,4 @@
-{-# OPTIONS_GHC -fno-warn-deprecations #-}
+{-# OPTIONS_GHC -fno-warn-deprecations -fno-warn-incomplete-uni-patterns #-}
 
 module Handler.Utils.Exam
   ( fetchExamAux
@@ -24,7 +24,6 @@ import qualified Data.Conduit.List as C
 import qualified Data.Map as Map
 import qualified Data.Set as Set
 
-import Data.Fixed (Fixed(..))
 import qualified Data.Foldable as F
 
 import qualified Data.CaseInsensitive as CI
diff --git a/src/Handler/Utils/Form.hs b/src/Handler/Utils/Form.hs
index dd9cadba6..f3b38f2d3 100644
--- a/src/Handler/Utils/Form.hs
+++ b/src/Handler/Utils/Form.hs
@@ -14,6 +14,8 @@ import Handler.Utils.Pandoc
 
 import Handler.Utils.DateTime
 
+import Handler.Utils.Widgets
+
 import Import
 import Data.Char (chr, ord)
 import qualified Data.Char as Char
@@ -31,19 +33,15 @@ import qualified Data.Conduit.List as C
 import qualified Database.Esqueleto as E
 import qualified Database.Esqueleto.Utils as E
 
-import Data.Set (Set)
 import qualified Data.Set as Set
 
-import Data.Map (Map, (!))
+import Data.Map ((!))
 import qualified Data.Map as Map
 
-import Control.Monad.Trans.Writer (execWriterT, WriterT)
 import Control.Monad.Trans.Except (throwE, runExceptT)
 import Control.Monad.Writer.Class
 import Control.Monad.Error.Class (MonadError(..))
 
-import Data.Either (partitionEithers)
-
 import Data.Aeson (eitherDecodeStrict')
 import Data.Aeson.Text (encodeToLazyText)
 
@@ -51,7 +49,6 @@ import qualified Text.Email.Validate as Email
 
 import Yesod.Core.Types (FileInfo(..))
 
-import System.FilePath (isExtensionOf)
 import Data.Text.Lens (unpacked)
 
 import Data.Char (isDigit)
@@ -548,6 +545,7 @@ uploadModeForm prev = multiActionA actions (fslI MsgSheetUploadMode) (classifyUp
           return (addRes', formWidget')
         miCell _ initFile _ nudge csrf =
           sFileForm nudge (Just initFile) csrf
+        miDelete :: MassInputDelete ListLength
         miDelete = miDeleteList
         miAllowAdd _ _ _ = True
         miAddEmpty _ _ _ = Set.empty
@@ -815,7 +813,8 @@ multiFileField permittedFiles' = Field{..}
                 | Right sentVals' <- sentVals = fuiId' `elem` sentVals'
                 | otherwise = True
           return FileUploadInfo{..}
-        autoUnzipInfo = [whamlet| _{MsgAutoUnzipInfo} |]
+        autoUnzipInfo :: Widget
+        autoUnzipInfo = i18n MsgAutoUnzipInfo
       fileInfos' <- mapM toFUI <=< handlerToWidget . runDB . E.select . E.from $ \file -> do
           E.where_ $ file E.^. FileId `E.in_` E.valList (setToList pVals)
           E.orderBy [E.asc $ file E.^. FileTitle]
diff --git a/src/Handler/Utils/Form/MassInput.hs b/src/Handler/Utils/Form/MassInput.hs
index a0ba3dfb4..ef53aeb4d 100644
--- a/src/Handler/Utils/Form/MassInput.hs
+++ b/src/Handler/Utils/Form/MassInput.hs
@@ -1,8 +1,8 @@
-{-# OPTIONS_GHC -fno-warn-orphans #-} -- tupleBoxCoord
+{-# OPTIONS_GHC -fno-warn-orphans -fno-warn-incomplete-record-updates #-} -- tupleBoxCoord
 {-# LANGUAGE GeneralizedNewtypeDeriving, UndecidableInstances #-}
 
 module Handler.Utils.Form.MassInput
-  ( MassInput(..), MassInputLayout
+  ( MassInput(..), MassInputLayout, MassInputDelete
   , defaultMiLayout, listMiLayout
   , massInput
   , module Handler.Utils.Form.MassInput.Liveliness
@@ -34,6 +34,8 @@ import Control.Monad.Reader.Class (MonadReader(local))
 
 import Text.Hamlet (hamletFile)
 
+import Algebra.Lattice.Ordered (Ordered(..))
+
 
 $(mapM tupleBoxCoord [2..4])
 
@@ -44,11 +46,8 @@ newtype ListLength = ListLength { unListLength :: Natural }
 
 makeWrapped ''ListLength
 
-instance JoinSemiLattice ListLength where
-  (\/) = max
-instance MeetSemiLattice ListLength where
-  (/\) = min
-instance Lattice ListLength
+deriving via Ordered ListLength instance Lattice ListLength
+
 instance BoundedJoinSemiLattice ListLength where
   bottom = 0
 
@@ -85,16 +84,13 @@ newtype EnumLiveliness enum = EnumLiveliness { unEnumLiveliness :: IntSet }
 
 makeWrapped ''EnumLiveliness
 
-instance JoinSemiLattice (EnumLiveliness enum) where
+instance Lattice (EnumLiveliness enum) where
   (EnumLiveliness a) \/ (EnumLiveliness b) = EnumLiveliness $ a `IntSet.union` b
-instance MeetSemiLattice (EnumLiveliness enum) where
   (EnumLiveliness a) /\ (EnumLiveliness b) = EnumLiveliness $ a `IntSet.intersection` b
-instance Lattice (EnumLiveliness enum)
 instance BoundedJoinSemiLattice (EnumLiveliness enum) where
   bottom = EnumLiveliness IntSet.empty
 instance (Enum enum, Bounded enum) => BoundedMeetSemiLattice (EnumLiveliness enum) where
   top = EnumLiveliness . IntSet.fromList $ map (fromEnum :: enum -> Int) [minBound..maxBound]
-instance (Enum enum, Bounded enum) => BoundedLattice (EnumLiveliness enum)
 
 
 newtype EnumPosition enum = EnumPosition { unEnumPosition :: enum }
@@ -111,7 +107,9 @@ instance (Enum enum, Bounded enum, PathPiece enum, ToJSON enum, FromJSON enum, T
   type BoxCoord (EnumLiveliness enum) = EnumPosition enum
   liveCoords = iso fromSet toSet
     where
+      toSet :: EnumLiveliness enum -> Set (EnumPosition enum)
       toSet = Set.fromList . map toEnum . IntSet.toList . unEnumLiveliness
+      fromSet :: Set (EnumPosition enum) -> EnumLiveliness enum
       fromSet = EnumLiveliness . IntSet.fromList . map fromEnum . Set.toList
 
 
@@ -120,12 +118,9 @@ newtype MapLiveliness l1 l2 = MapLiveliness { unMapLiveliness :: Map (BoxCoord l
 
 makeWrapped ''MapLiveliness
 
-deriving instance (Ord (BoxCoord l1), JoinSemiLattice l2) => JoinSemiLattice (MapLiveliness l1 l2)
-deriving instance (Ord (BoxCoord l1), MeetSemiLattice l2) => MeetSemiLattice (MapLiveliness l1 l2)
 deriving instance (Ord (BoxCoord l1), Lattice l2) => Lattice (MapLiveliness l1 l2)
 deriving instance (Ord (BoxCoord l1), BoundedJoinSemiLattice l2) => BoundedJoinSemiLattice (MapLiveliness l1 l2)
 deriving instance (Ord (BoxCoord l1), Finite (BoxCoord l1), BoundedMeetSemiLattice l2) => BoundedMeetSemiLattice (MapLiveliness l1 l2)
-deriving instance (Ord (BoxCoord l1), Finite (BoxCoord l1), BoundedLattice l2) => BoundedLattice (MapLiveliness l1 l2)
 deriving instance (Eq (BoxCoord l1), Eq l2) => Eq (MapLiveliness l1 l2)
 deriving instance (Ord (BoxCoord l1), Ord l2) => Ord (MapLiveliness l1 l2)
 deriving instance (Ord (BoxCoord l1), Read (BoxCoord l1), Read l2) => Read (MapLiveliness l1 l2)
@@ -138,8 +133,10 @@ instance (Liveliness l1, Liveliness l2) => Liveliness (MapLiveliness l1 l2) wher
     (\ts -> let ks = Set.mapMonotonic fst ts in fmap MapLiveliness . sequence $ Map.fromSet (\k -> preview liveCoords . Set.mapMonotonic snd $ Set.filter ((== k) . fst) ts) ks)
 
 
+type MassInputDelete liveliness = forall m a. Applicative m => Map (BoxCoord liveliness) a -> (BoxCoord liveliness) -> m (Map (BoxCoord liveliness) (BoxCoord liveliness))
 
-miDeleteList :: Applicative m => Map ListPosition a -> ListPosition -> m (Map ListPosition ListPosition)
+
+miDeleteList :: MassInputDelete ListLength
 miDeleteList dat pos
     -- Close gap left by deleted position with values from further down the list; try prohibiting certain deletions by utilising `guard`
   | Just l <- preview liveCoords $ Map.keysSet dat :: Maybe ListLength
@@ -289,6 +286,7 @@ massInput MassInput{ miIdent = toPathPiece -> miIdent, ..} FieldSettings{..} fvR
   let
     shapeName :: MassInputFieldName (BoxCoord liveliness)
     shapeName = MassInputShape{..}
+    shapeField :: Field handler (Map (BoxCoord liveliness) cellData)
     shapeField = secretJsonField
   sentShape <- runMaybeT $ do
     ts <- fromMaybe [] . Map.lookup (toPathPiece shapeName) <$> MaybeT askParams
@@ -536,6 +534,7 @@ massInputAccum miAdd' miCell' miButtonAction miLayout miIdent fSettings fRequire
            -> (Markup -> MForm handler (FormResult (), Widget))
     miCell _pos dat _mPrev _nudge csrf' = return (FormSuccess (), toWidget csrf' <> miCell' dat)
 
+    miDelete :: MassInputDelete ListLength
     miDelete = miDeleteList
 
     miAllowAdd _ _ _ = True
@@ -613,6 +612,7 @@ massInputAccumEdit miAdd' miCell' miButtonAction miLayout miIdent fSettings fReq
            -> (Markup -> MForm handler (FormResult cellData, Widget))
     miCell _pos dat _mPrev nudge = miCell' nudge dat
 
+    miDelete :: MassInputDelete ListLength
     miDelete = miDeleteList
 
     miAllowAdd _ _ _ = True
diff --git a/src/Handler/Utils/Form/MassInput/Liveliness.hs b/src/Handler/Utils/Form/MassInput/Liveliness.hs
index 9891350d8..14709ec9b 100644
--- a/src/Handler/Utils/Form/MassInput/Liveliness.hs
+++ b/src/Handler/Utils/Form/MassInput/Liveliness.hs
@@ -26,11 +26,12 @@ class (ToJSON x, FromJSON x, ToJSONKey x, FromJSONKey x, PathPiece x, Eq x, Ord
   boxDimensions :: [BoxDimension x]
   boxOrigin :: x
 
-boxDimension :: IsBoxCoord x => Natural -> BoxDimension x
+boxDimension :: forall x. IsBoxCoord x => Natural -> BoxDimension x
 boxDimension n
   | n < genericLength dims = genericIndex dims n
   | otherwise = error "boxDimension: insufficient dimensions"
   where
+    dims :: [BoxDimension x]
     dims = boxDimensions
 
 -- zeroDimension :: IsBoxCoord x => Natural -> x -> x
diff --git a/src/Handler/Utils/Form/MassInput/TH.hs b/src/Handler/Utils/Form/MassInput/TH.hs
index 01d0e8e56..dac5203b0 100644
--- a/src/Handler/Utils/Form/MassInput/TH.hs
+++ b/src/Handler/Utils/Form/MassInput/TH.hs
@@ -11,8 +11,6 @@ import Language.Haskell.TH
 
 import Control.Lens
 
-import Data.List ((!!))
-
 import Control.Monad (replicateM)
 
 
diff --git a/src/Handler/Utils/I18n.hs b/src/Handler/Utils/I18n.hs
index 03ae640e6..0394aa578 100644
--- a/src/Handler/Utils/I18n.hs
+++ b/src/Handler/Utils/I18n.hs
@@ -20,7 +20,6 @@ import qualified Data.Map as Map
 import qualified Data.Text as Text
 
 import System.Directory (listDirectory)
-import System.FilePath.Posix (takeBaseName)
 
 
 -- | Add language dependent template files
diff --git a/src/Handler/Utils/Invitations.hs b/src/Handler/Utils/Invitations.hs
index 983ea7b3c..2da19bd90 100644
--- a/src/Handler/Utils/Invitations.hs
+++ b/src/Handler/Utils/Invitations.hs
@@ -25,9 +25,6 @@ import Handler.Utils.Tokens
 
 import Text.Hamlet
 
-import Control.Monad.Trans.Writer (WriterT) 
-import Control.Monad.Trans.Reader (mapReaderT, withReaderT)
-
 import qualified Data.Conduit.List as C
 import qualified Data.List.NonEmpty as NonEmpty
 import qualified Data.HashSet as HashSet
@@ -36,7 +33,6 @@ import qualified Data.Set as Set
 import Data.Aeson (fromJSON)
 import qualified Data.Aeson as JSON
 
-import Data.Proxy (Proxy(..))
 import Data.Typeable
 
 import Database.Persist.Sql (SqlBackendCanWrite)
diff --git a/src/Handler/Utils/Mail.hs b/src/Handler/Utils/Mail.hs
index d40782758..f564ae3d4 100644
--- a/src/Handler/Utils/Mail.hs
+++ b/src/Handler/Utils/Mail.hs
@@ -15,10 +15,6 @@ import qualified Data.ByteString.Lazy as LBS
 
 import qualified Data.Conduit.List as C
 
-import System.FilePath (takeBaseName)
-
-import Control.Monad.Trans.State (StateT)
-
 import qualified Text.Pandoc as P
 
 import qualified Text.Hamlet as Hamlet (Translate)
@@ -79,8 +75,8 @@ addFileDB fId = runMaybeT $ do
   lift . addPart $ do
     _partType .= decodeUtf8 (mimeLookup fileName)
     _partEncoding .= Base64
-    _partFilename .= Just fileName
-    _partContent .= LBS.fromStrict fileContent
+    _partDisposition .= AttachmentDisposition fileName
+    _partContent .= PartContent (LBS.fromStrict fileContent)
     setMailObjectIdCrypto fId :: StateT Part (HandlerFor UniWorX) MailObjectId
 
 
diff --git a/src/Handler/Utils/Rating.hs b/src/Handler/Utils/Rating.hs
index 4bea35d2b..d96ae3784 100644
--- a/src/Handler/Utils/Rating.hs
+++ b/src/Handler/Utils/Rating.hs
@@ -20,11 +20,9 @@ import Text.PrettyPrint.Leijen.Text hiding ((<$>))
 
 import qualified Data.Text as Text
 import qualified Data.Text.Encoding as Text
-import Data.Text.Encoding.Error (UnicodeException(..))
 
 import qualified Data.Text.Lazy.Encoding as Lazy.Text
 
-import Data.CaseInsensitive (CI)
 import qualified Data.CaseInsensitive as CI
 
 import qualified Data.ByteString.Lazy as Lazy (ByteString)
@@ -138,8 +136,10 @@ parseRating File{ fileContent = Just input, .. } = do
     (headerLines', commentLines) = break (commentSep `Text.isInfixOf`) $ Text.lines inputText
     (reverse -> ratingLines, reverse -> _headerLines) = break (sep' `Text.isInfixOf`) $ reverse headerLines'
     ratingLines' = filter (rating `Text.isInfixOf`) ratingLines
+    commentSep :: Text
     commentSep = "Beginn der Kommentare"
     sep' = Text.pack $ replicate 40 '='
+    rating :: Text
     rating = "Bewertung:"
   comment' <- case commentLines of
     (_:commentLines') -> return . Text.strip $ Text.unlines commentLines'
diff --git a/src/Handler/Utils/SchoolLdap.hs b/src/Handler/Utils/SchoolLdap.hs
index b9b825aff..782d533c9 100644
--- a/src/Handler/Utils/SchoolLdap.hs
+++ b/src/Handler/Utils/SchoolLdap.hs
@@ -7,7 +7,6 @@ import Import.NoFoundation hiding (try, (<|>), choice)
 import Text.Parsec
 import Text.Parsec.Text
 
-import Data.CaseInsensitive (CI)
 import qualified Data.CaseInsensitive as CI
 
 import qualified Data.Set as Set
diff --git a/src/Handler/Utils/SheetType.hs b/src/Handler/Utils/SheetType.hs
index 494729793..5f269fa55 100644
--- a/src/Handler/Utils/SheetType.hs
+++ b/src/Handler/Utils/SheetType.hs
@@ -4,7 +4,6 @@ module Handler.Utils.SheetType
   ) where
 
 import Import
-import Data.Monoid (Sum(..))
 
 addBonusToPoints :: SheetTypeSummary -> SheetTypeSummary
 addBonusToPoints sts =
diff --git a/src/Handler/Utils/Submission.hs b/src/Handler/Utils/Submission.hs
index 23d9aed0b..ee7e7fc56 100644
--- a/src/Handler/Utils/Submission.hs
+++ b/src/Handler/Utils/Submission.hs
@@ -13,24 +13,20 @@ module Handler.Utils.Submission
 
 import Import hiding (joinPath)
 import Jobs.Queue
-import Yesod.Core.Types (HandlerContents(..), ErrorResponse(..))
+import Yesod.Core.Types (HandlerContents(..))
 
-import Control.Monad.State as State (StateT)
 import Control.Monad.State.Class as State
-import Control.Monad.Writer (MonadWriter(..), execWriterT, execWriter)
 import Control.Monad.RWS.Lazy (MonadRWS, RWST, execRWST)
 import qualified Control.Monad.Random as Rand
 
 import Data.Maybe ()
 
-import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Map (Map, (!), (!?))
+import Data.Map ((!), (!?))
 import qualified Data.Map as Map
 
 import qualified Data.Text as Text
 
-import Data.Monoid (Monoid, Any(..), Sum(..))
 import Generics.Deriving.Monoid (memptydefault, mappenddefault)
 
 import Handler.Utils
diff --git a/src/Handler/Utils/Submission/TH.hs b/src/Handler/Utils/Submission/TH.hs
index 0b24a4da1..14504b6cf 100644
--- a/src/Handler/Utils/Submission/TH.hs
+++ b/src/Handler/Utils/Submission/TH.hs
@@ -10,7 +10,6 @@ import Language.Haskell.TH.Syntax (qAddDependentFile, Lift(..))
 
 import System.FilePath.Glob
 
-import Data.Text (Text)
 import qualified Data.Text as Text
 import qualified Data.Text.IO as Text
 
diff --git a/src/Handler/Utils/Table/Cells.hs b/src/Handler/Utils/Table/Cells.hs
index 5a53a8070..eae560b6a 100644
--- a/src/Handler/Utils/Table/Cells.hs
+++ b/src/Handler/Utils/Table/Cells.hs
@@ -2,12 +2,7 @@ module Handler.Utils.Table.Cells where
 
 import Import hiding (link)
 
-import Data.CaseInsensitive (CI)
--- import qualified Data.CaseInsensitive as CI
-
-import Data.Monoid (Any(..))
 import Control.Monad.Writer.Class (MonadWriter(..))
-import Control.Monad.Trans.Writer (WriterT)
 
 import Text.Blaze (ToMarkup(..))
 
diff --git a/src/Handler/Utils/Table/Pagination.hs b/src/Handler/Utils/Table/Pagination.hs
index 53184935c..e3689add8 100644
--- a/src/Handler/Utils/Table/Pagination.hs
+++ b/src/Handler/Utils/Table/Pagination.hs
@@ -61,21 +61,18 @@ import qualified Yesod.Form.Functions as Yesod
 import qualified Database.Esqueleto as E
 import qualified Database.Esqueleto.Utils as E
 import qualified Database.Esqueleto.Internal.Sql as E (SqlSelect,unsafeSqlValue)
-import qualified Database.Esqueleto.Internal.Language as E (From)
 
 import qualified Network.Wai as Wai
 
 import Control.Monad.RWS (RWST(..), execRWS)
-import Control.Monad.Writer (WriterT(..))
-import Control.Monad.Reader (ReaderT(..), mapReaderT)
-import Control.Monad.State (StateT(..), evalStateT)
+import Control.Monad.State (evalStateT)
 import Control.Monad.Trans.Maybe
 import Control.Monad.State.Class (modify)
 import qualified Control.Monad.State.Class as State
 
 import Data.Foldable (Foldable(foldMap))
 
-import Data.Map (Map, (!))
+import Data.Map ((!))
 import qualified Data.Map as Map
 
 import qualified Data.Set as Set
@@ -90,20 +87,14 @@ import Colonnade.Encode hiding (row)
 
 import Text.Hamlet (hamletFile)
 
-import Data.Ratio ((%))
-
 import Data.List (elemIndex)
 
 import Data.Maybe (fromJust)
 
-import Data.Aeson (Options(..), SumEncoding(..), defaultOptions)
 import Data.Aeson.Text
-import Data.Aeson.TH (deriveJSON)
 
 import qualified Data.Text as Text
 
-import Data.Proxy (Proxy(..))
-
 import qualified Data.Binary as B
 import qualified Data.ByteArray as BA (convert)
 import Crypto.MAC.HMAC (hmac, HMAC)
@@ -140,7 +131,8 @@ instance PathPiece x => PathPiece (WithIdent x) where
     | not . null $ toPathPiece ident = toPathPiece ident <> "-" <> toPathPiece x
     | otherwise = toPathPiece x
   fromPathPiece txt = do
-    let sep = "-"
+    let sep :: Text
+        sep = "-"
     (ident, (Text.stripSuffix sep -> Just rest)) <- return $ Text.breakOn sep txt
     WithIdent <$> pure ident <*> fromPathPiece rest
 
@@ -188,7 +180,8 @@ deriveJSON defaultOptions
 instance PathPiece SortingSetting where
   toPathPiece SortingSetting{..} = toPathPiece sortKey <> "-" <> toPathPiece sortDir
   fromPathPiece str = do
-    let sep = "-"
+    let sep :: Text
+        sep = "-"
     let (Text.dropEnd (Text.length sep) -> key, dir) = Text.breakOnEnd sep str
     SortingSetting <$> fromPathPiece key <*> fromPathPiece dir
 
@@ -829,8 +822,9 @@ dbTable PSValidator{..} dbtable@DBTable{ dbtIdent = dbtIdent'@(toPathPiece -> db
     dbsAttrs'
       | not $ null dbtIdent = ("id", dbtIdent) : dbsAttrs
       | otherwise           = dbsAttrs
+    multiTextField :: forall m'. Applicative m' => Field m' [Text]
     multiTextField = Field
-      { fieldParse = \ts _ -> return . Right $ Just ts
+      { fieldParse = \ts _ -> pure . Right $ Just ts
       , fieldView = error "multiTextField: should not be rendered"
       , fieldEnctype = UrlEncoded
       }
@@ -939,6 +933,7 @@ dbTable PSValidator{..} dbtable@DBTable{ dbtIdent = dbtIdent'@(toPathPiece -> db
       , formSubmit = FormSubmit
       , formAnchor = Just $ wIdent "csv-import"
       }
+    csvImportExplanation :: Widget
     csvImportExplanation = modal [whamlet|_{MsgCsvImportExplanationLabel}|] $ Right $(i18nWidgetFile "table/csv-import-explanation")
     csvColExplanations = case dbtCsvEncode of
       Just (DBTCsvEncode{} :: DBTCsvEncode r' k' csv) -> assertM' (not . null) . Map.toList . csvColumnsExplanations $ Proxy @csv
@@ -1246,6 +1241,7 @@ pagesizeOptions psLim = impureNonNull . Set.toAscList . Set.fromList $ psLim : P
     opts :: [Int64]
     opts = filter (> 0) $ opts' <> map (`div` 2) opts'
 
+    opts' :: [Int64]
     opts' = [ 10^n | n <- [1..3]]
 
 pagesizeField :: PagesizeLimit -> Field Handler PagesizeLimit
diff --git a/src/Handler/Utils/Table/Pagination/Types.hs b/src/Handler/Utils/Table/Pagination/Types.hs
index 64da8980a..141e0b0b9 100644
--- a/src/Handler/Utils/Table/Pagination/Types.hs
+++ b/src/Handler/Utils/Table/Pagination/Types.hs
@@ -14,10 +14,6 @@ import Import hiding (singleton)
 import Colonnade
 import Colonnade.Encode
 
-import Data.CaseInsensitive (CI)
-
-import Data.Aeson (FromJSON, ToJSON, FromJSONKey, ToJSONKey)
-
 {-# ANN module ("HLint: ignore Use newtype instead of data" :: String) #-}
 
 newtype FilterKey = FilterKey { _unFilterKey :: CI Text }
diff --git a/src/Handler/Utils/TermCandidates.hs b/src/Handler/Utils/TermCandidates.hs
index 729fd0eaa..7d49f451f 100644
--- a/src/Handler/Utils/TermCandidates.hs
+++ b/src/Handler/Utils/TermCandidates.hs
@@ -17,10 +17,8 @@ import Import
 -- import qualified Data.UUID.Cryptographic as UUID
 -- import Control.Monad.Trans.Writer (mapWriterT)
 -- import Database.Persist.Sql (fromSqlKey)
-import Data.Set (Set)
 import qualified Data.Set as Set
 import qualified Data.List as List
-import Data.Map (Map)
 import qualified Data.Map as Map
 
 
diff --git a/src/Handler/Utils/Tokens.hs b/src/Handler/Utils/Tokens.hs
index 54a0b4da5..e7d831cba 100644
--- a/src/Handler/Utils/Tokens.hs
+++ b/src/Handler/Utils/Tokens.hs
@@ -5,8 +5,6 @@ module Handler.Utils.Tokens
 
 import Import
 
-import Control.Monad.Trans.Maybe (runMaybeT)
-
 
 maybeBearerToken :: (MonadHandler m, HandlerSite m ~ UniWorX, MonadCatch m) => m (Maybe (BearerToken UniWorX))
 maybeBearerToken = runMaybeT $ catchIfMaybeT cPred requireBearerToken
diff --git a/src/Handler/Utils/Users.hs b/src/Handler/Utils/Users.hs
index df7125023..dc23e8739 100644
--- a/src/Handler/Utils/Users.hs
+++ b/src/Handler/Utils/Users.hs
@@ -9,7 +9,7 @@ module Handler.Utils.Users
 import Import
 import Auth.LDAP (campusUserMatr')
 
-import Crypto.Hash (Digest, SHA3_256, hashlazy)
+import Crypto.Hash (hashlazy)
 
 import Data.ByteArray (constEq)
 
diff --git a/src/Handler/Utils/Widgets.hs b/src/Handler/Utils/Widgets.hs
index be3e0424d..b9e5b5f95 100644
--- a/src/Handler/Utils/Widgets.hs
+++ b/src/Handler/Utils/Widgets.hs
@@ -109,6 +109,7 @@ i18n = toWidget . (SomeMessage :: msg -> SomeMessage (HandlerSite m))
 examOccurrenceMappingDescriptionWidget :: ExamOccurrenceRule -> Set ExamOccurrenceMappingDescription -> Widget
 examOccurrenceMappingDescriptionWidget rule descriptions = $(widgetFile "widgets/exam-occurrence-mapping-description")
   where
+    titleCase :: [CI Char] -> String
     titleCase = over _head Char.toUpper . map CI.foldedCase
     doPrefix
       | ExamRoomMatriculation <- rule
diff --git a/src/Handler/Utils/Zip.hs b/src/Handler/Utils/Zip.hs
index 3948253f9..9ee8fbf96 100644
--- a/src/Handler/Utils/Zip.hs
+++ b/src/Handler/Utils/Zip.hs
@@ -20,7 +20,6 @@ import Codec.Archive.Zip.Conduit.Zip
 -- import qualified Data.ByteString.Lazy as Lazy (ByteString)
 import qualified Data.ByteString.Lazy as Lazy.ByteString
 
-import Data.ByteString (ByteString)
 import qualified Data.ByteString as ByteString
 
 import System.FilePath
diff --git a/src/Import/NoModel.hs b/src/Import/NoModel.hs
index 618a783b6..d01136a6d 100644
--- a/src/Import/NoModel.hs
+++ b/src/Import/NoModel.hs
@@ -1,6 +1,7 @@
 module Import.NoModel
   ( module Import
   , MForm
+  , WeekDay
   ) where
 
 import ClassyPrelude.Yesod    as Import
@@ -16,7 +17,6 @@ import ClassyPrelude.Yesod    as Import
          , HasHttpManager(..)
          , embed
          , try, embed, catches, handle, catch, bracket, bracketOnError, bracket_, catchJust, finally, handleJust, mask, mask_, onException, tryJust, uninterruptibleMask, uninterruptibleMask_
-         , fail
          , htmlField
          )
 
@@ -30,7 +30,6 @@ import Mail                   as Import
 import Yesod.Auth             as Import
 import Yesod.Core.Types       as Import (loggerSet)
 import Yesod.Default.Config2  as Import
-import Yesod.Core.Json        as Import (provideJson)
 import Yesod.Core.Types.Instances as Import
 
 import Utils                  as Import
@@ -53,15 +52,13 @@ import UnliftIO.Pool          as Import (Pool)
 import Network.HaskellNet.SMTP as Import (SMTPConnection)
 
 import Data.Data              as Import (Data)
-import Data.Typeable          as Import (Typeable)
-import GHC.Generics           as Import (Generic)
 import GHC.Exts               as Import (IsList)
 import Data.Ix                as Import (Ix)
 
 import Data.Hashable          as Import
 import Data.List.NonEmpty     as Import (NonEmpty(..), nonEmpty)
 import Data.Text.Encoding.Error as Import(UnicodeException(..))
-import Data.Semigroup         as Import (Semigroup, Min(..), Max(..))
+import Data.Semigroup         as Import (Min(..), Max(..))
 import Data.Monoid            as Import (Last(..), First(..), Any(..), All(..), Sum(..), Endo(..), Alt(..))
 import Data.Binary            as Import (Binary)
 
@@ -82,8 +79,8 @@ import Control.Monad.Random.Class as Import (MonadRandom(..))
 import Control.Monad.Morph as Import
 import Control.Monad.Trans.Resource as Import (ReleaseKey)
 import Control.Monad.Trans.Reader as Import
-  ( reader, Reader, runReader, mapReader, withReader
-  , ReaderT(..), mapReaderT, withReaderT
+  ( reader, runReader, mapReader, withReader
+  , mapReaderT, withReaderT
   )
 import Control.Monad.Trans.State as Import
   ( state, State, runState, mapState, withState
@@ -103,17 +100,15 @@ import Jose.Jwt as Import (Jwt)
 import Data.Time.Calendar as Import
 import Data.Time.Clock as Import
 import Data.Time.LocalTime as Import hiding (utcToLocalTime, utcToZonedTime, localTimeToUTC)
-import Time.Types as Import (WeekDay(..))
 
 import Network.Mime as Import
 
 import Data.Aeson.TH as Import
-import Data.Aeson.Types as Import (FromJSON(..), ToJSON(..), FromJSONKey(..), ToJSONKey(..), toJSONKeyText, FromJSONKeyFunction(..), ToJSONKeyFunction(..), Value)
+import Data.Aeson.Types as Import (FromJSONKey(..), ToJSONKey(..), toJSONKeyText, FromJSONKeyFunction(..), ToJSONKeyFunction(..))
 
 import Data.Constraint as Import (Dict(..))
-import Data.Void as Import (Void)
 
-import Algebra.Lattice as Import hiding (meet, join)
+import Algebra.Lattice as Import
 
 import Data.Proxy as Import (Proxy(..))
 
@@ -133,7 +128,6 @@ import Data.Time.Clock.Instances as Import ()
 import Data.Time.LocalTime.Instances as Import ()
 import Data.Time.Calendar.Instances as Import ()
 import Data.Time.Format.Instances as Import ()
-import Time.Types.Instances as Import ()
 import Network.Mail.Mime.Instances as Import ()
 import Yesod.Core.Instances as Import ()
 import Data.Aeson.Types.Instances as Import ()
@@ -177,3 +171,5 @@ import Data.Encoding.UTF8 as Import (UTF8(UTF8))
 import Control.Monad.Trans.RWS (RWST)
 
 type MForm m = RWST (Maybe (Env, FileEnv), HandlerSite m, [Lang]) Enctype Ints m
+
+type WeekDay = DayOfWeek
diff --git a/src/Jobs.hs b/src/Jobs.hs
index 423e0c20c..600294731 100644
--- a/src/Jobs.hs
+++ b/src/Jobs.hs
@@ -7,7 +7,6 @@ module Jobs
 
 import Import
 import Jobs.Types as Types hiding (JobCtl(JobCtlQueue))
-import Jobs.Types (JobCtl(JobCtlQueue))
 import Jobs.Queue
 import Jobs.Crontab
 
@@ -18,17 +17,13 @@ import qualified Data.Text.Lazy as LT
 import Data.Aeson (fromJSON)
 import qualified Data.Aeson as Aeson
 import qualified Data.Aeson.Types as Aeson
-import Database.Persist.Sql (fromSqlKey)
-
-import Data.Semigroup (Max(..))
 
 import Utils.Sql
 
-import Control.Monad.Random (evalRand, mkStdGen, getRandomR, uniformMay)
+import Control.Monad.Random (evalRand, mkStdGen, uniformMay)
 
 import Cron
 import qualified Data.HashMap.Strict as HashMap
-import Data.HashMap.Strict (HashMap)
 import qualified Data.Set as Set
 
 import qualified Data.List.NonEmpty as NonEmpty
@@ -36,16 +31,9 @@ import qualified Data.List.NonEmpty as NonEmpty
 import qualified Data.Map.Strict as Map
 import Data.Map.Strict ((!))
 
-import Data.Foldable (foldrM)
-
-import Control.Monad.Trans.Reader (mapReaderT)
-import Control.Monad.Trans.Writer (execWriterT)
 import Control.Monad.Trans.RWS.Lazy (RWST, mapRWST, evalRWST)
 import qualified Control.Monad.State.Class as State
 import Control.Monad.Writer.Class (MonadWriter(..))
-import Control.Monad.Reader.Class (MonadReader(..))
-import Control.Monad.Trans.Resource (runResourceT)
-import Control.Monad.Trans.Maybe (MaybeT(..))
 import Control.Monad.Trans.Cont (ContT(..), callCC)
 import Control.Monad.Random.Lazy (evalRandTIO, mapRandT)
 import Control.Monad.Logger
diff --git a/src/Jobs/Crontab.hs b/src/Jobs/Crontab.hs
index 9c5d81203..b631b052e 100644
--- a/src/Jobs/Crontab.hs
+++ b/src/Jobs/Crontab.hs
@@ -1,3 +1,5 @@
+{-# OPTIONS_GHC -fno-warn-incomplete-record-updates #-}
+
 module Jobs.Crontab
   ( determineCrontab
   ) where
@@ -9,7 +11,6 @@ import Jobs.Types
 
 import qualified Data.Set as Set
 import qualified Data.Map as Map
-import Data.Semigroup (Max(..))
 
 import Data.Time.Zones
 import Data.Time.Clock.POSIX
@@ -17,7 +18,6 @@ import Data.Time.Clock.POSIX
 import Handler.Utils.DateTime
 import Handler.Utils.Allocation (allocationDone)
 
-import Control.Monad.Trans.Writer (WriterT, execWriterT)
 import Control.Monad.Writer.Class (MonadWriter(..))
 
 import qualified Data.Conduit.List as C
diff --git a/src/Jobs/Handler/DistributeCorrections.hs b/src/Jobs/Handler/DistributeCorrections.hs
index 192c4dea3..af61ddfb7 100644
--- a/src/Jobs/Handler/DistributeCorrections.hs
+++ b/src/Jobs/Handler/DistributeCorrections.hs
@@ -6,8 +6,6 @@ import Import
 
 import Jobs.Queue
 
-import Control.Monad.Trans.Reader (mapReaderT)
-
 import Handler.Utils.Submission
 
 import qualified Data.Set as Set
diff --git a/src/Jobs/Handler/QueueNotification.hs b/src/Jobs/Handler/QueueNotification.hs
index c38575bbc..394516dac 100644
--- a/src/Jobs/Handler/QueueNotification.hs
+++ b/src/Jobs/Handler/QueueNotification.hs
@@ -4,8 +4,6 @@ module Jobs.Handler.QueueNotification
 
 import Import
 
-import Data.List (nub)
-
 import Jobs.Types
 
 import qualified Database.Esqueleto as E
diff --git a/src/Jobs/Handler/SendCourseCommunication.hs b/src/Jobs/Handler/SendCourseCommunication.hs
index 1cb5ea554..2030d0c29 100644
--- a/src/Jobs/Handler/SendCourseCommunication.hs
+++ b/src/Jobs/Handler/SendCourseCommunication.hs
@@ -12,6 +12,9 @@ import qualified Data.CaseInsensitive as CI
 import Handler.Utils.Csv (partIsAttachmentCsv)
 
 
+{-# ANN module ("HLint: ignore Too strict maybe"::String) #-}
+
+
 dispatchJobSendCourseCommunication :: Either UserEmail UserId
                                    -> Set Address
                                    -> CourseId
diff --git a/src/Jobs/Handler/SynchroniseLdap.hs b/src/Jobs/Handler/SynchroniseLdap.hs
index 3769f76a4..1c82569ed 100644
--- a/src/Jobs/Handler/SynchroniseLdap.hs
+++ b/src/Jobs/Handler/SynchroniseLdap.hs
@@ -51,6 +51,7 @@ dispatchJobSynchroniseLdapUser jUser = do
     Nothing ->
       throwM SynchroniseLdapNoLdap
   where
+    handleExc :: MaybeT DB a -> MaybeT DB a
     handleExc
       = catchMPlus (Proxy @CampusUserException)
       . catchMPlus (Proxy @CampusUserConversionException)
diff --git a/src/Jobs/HealthReport.hs b/src/Jobs/HealthReport.hs
index 60eb2aa7f..97fc6e229 100644
--- a/src/Jobs/HealthReport.hs
+++ b/src/Jobs/HealthReport.hs
@@ -10,7 +10,6 @@ import Data.List (genericLength)
 import qualified Data.Map.Strict as Map
 
 import qualified Data.Aeson as Aeson
-import Data.Proxy (Proxy(..))
 
 import qualified Data.ByteArray as ByteArray
 
@@ -124,7 +123,9 @@ dispatchHealthCheckWidgetMemcached :: Handler HealthReport
 dispatchHealthCheckWidgetMemcached = fmap HealthWidgetMemcached . yesodTimeout (^. _appHealthCheckActiveWidgetMemcachedTimeout) (Just False) $ do
   memcachedConn <- getsYesod appWidgetMemcached
   for memcachedConn $ \_memcachedConn' -> do
-    let ext = "bin"
+    let ext :: Text
+        ext = "bin"
+        mimeType :: Text
         mimeType = "application/octet-stream"
     content <- pack . take 256 <$> liftIO getRandoms
     staticLink <- addStaticContent ext mimeType content
diff --git a/src/Jobs/Queue.hs b/src/Jobs/Queue.hs
index c85ba0d9d..38158efe0 100644
--- a/src/Jobs/Queue.hs
+++ b/src/Jobs/Queue.hs
@@ -14,9 +14,7 @@ import Import hiding ((<>))
 import Utils.Sql
 import Jobs.Types
 
-import Control.Monad.Trans.Writer (WriterT, runWriterT)
 import Control.Monad.Writer.Class (MonadWriter(..))
-import Control.Monad.Trans.Reader (ReaderT, mapReaderT)
 
 import qualified Data.Map.Strict as Map
 import qualified Data.Set as Set
diff --git a/src/Jobs/Types.hs b/src/Jobs/Types.hs
index a22298065..54bb430cc 100644
--- a/src/Jobs/Types.hs
+++ b/src/Jobs/Types.hs
@@ -1,3 +1,4 @@
+{-# OPTIONS_GHC -fno-warn-incomplete-uni-patterns #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 
 module Jobs.Types
@@ -19,13 +20,9 @@ module Jobs.Types
 import Import.NoFoundation hiding (Unique, state)
 
 import qualified Data.Aeson as Aeson
-import Data.Aeson (defaultOptions, Options(..), SumEncoding(..))
-import Data.Aeson.TH (deriveJSON)
 
 import qualified Data.HashMap.Strict as HashMap
 
-import Data.List.NonEmpty (NonEmpty)
-
 import Data.Unique
 
 import qualified Data.Map.Strict as Map
diff --git a/src/Ldap/Client/Pool.hs b/src/Ldap/Client/Pool.hs
index 4668f4b23..9a33e9e0f 100644
--- a/src/Ldap/Client/Pool.hs
+++ b/src/Ldap/Client/Pool.hs
@@ -35,8 +35,6 @@ data LdapExecutor = LdapExecutor
   , ldapAsync :: Async ()
   }
 
-instance Exception LdapError
-
 data LdapPoolError = LdapPoolTimeout | LdapError LdapError
   deriving (Eq, Show, Generic, Typeable)
 
@@ -93,7 +91,10 @@ createLdapPool host port stripes timeoutConn (round . (* 1e6) -> timeoutAct) lim
                 $logErrorS "LdapExecutor" "Could not return result"
               either throwM (const $ return ()) res
                 `catches`
-                [ Handler (\(Ldap.ResponseError _) -> return ())
+                [ Handler $ \case
+                    Ldap.ResponseError   _ -> return ()
+                    Ldap.DisconnectError _ -> return ()
+                    other                  -> throwM other
                 ]
               go Nothing ldap
 
diff --git a/src/Mail.hs b/src/Mail.hs
index 81457b574..c472a75f2 100644
--- a/src/Mail.hs
+++ b/src/Mail.hs
@@ -33,7 +33,7 @@ module Mail
   , setMailSmtpData
   , _addressName, _addressEmail
   , _mailFrom, _mailTo, _mailCc, _mailBcc, _mailHeaders, _mailHeader, _mailParts
-  , _partType, _partEncoding, _partFilename, _partHeaders, _partContent
+  , _partType, _partEncoding, _partDisposition, _partFilename, _partHeaders, _partContent
   ) where
 
 import ClassyPrelude.Yesod hiding (snoc, (.=), getMessageRender, derivePersistFieldJSON)
@@ -49,18 +49,15 @@ import Data.Monoid (Last(..))
 import Control.Monad.Trans.RWS (RWST(..))
 import Control.Monad.Trans.State (StateT(..), execStateT, mapStateT)
 import Control.Monad.Trans.Writer (execWriter, Writer)
-import Control.Monad.RWS.Class (MonadWriter(..), MonadReader(..), MonadState(..), modify)
+import Control.Monad.RWS.Class (MonadWriter(..), MonadState(..), modify)
 import Control.Monad.Fail
 import Control.Monad.Base
 import Control.Monad.Catch
 
-import GHC.Generics (Generic)
 import Generics.Deriving.Monoid (memptydefault, mappenddefault)
 
-import Data.Sequence (Seq)
 import qualified Data.Sequence as Seq
 
-import Data.Set (Set)
 import qualified Data.Set as Set
 
 import qualified Data.Text as Text
@@ -88,7 +85,7 @@ import qualified Data.Binary as Binary
 
 import "network-bsd" Network.BSD (getHostName)
 
-import Data.Time.Zones (TZ, utcTZ, utcToLocalTimeTZ, timeZoneForUTCTime)
+import Data.Time.Zones (utcTZ, utcToLocalTimeTZ, timeZoneForUTCTime)
 import Data.Time.LocalTime (ZonedTime(..), TimeZone(..))
 import Data.Time.Format (rfc822DateFormat)
 
@@ -100,7 +97,6 @@ import qualified Text.Shakespeare as Shakespeare (RenderUrl)
 
 import qualified Data.Aeson as Aeson
 import qualified Data.Aeson.Encode.Pretty as Aeson
-import Data.Aeson (Options(..))
 import Data.Aeson.TH
 import Utils.PathPiece (splitCamel)
 import Utils.DateTime
@@ -125,6 +121,14 @@ makeLenses_ ''Address
 makeLenses_ ''Mail
 makeLenses_ ''Part
 
+_partFilename :: Traversal' Part Text
+_partFilename = _partDisposition . dispositionFilename
+  where
+    dispositionFilename :: Traversal' Disposition Text
+    dispositionFilename f (AttachmentDisposition t) = AttachmentDisposition <$> f t
+    dispositionFilename f (InlineDisposition     t) = InlineDisposition     <$> f t
+    dispositionFilename _  DefaultDisposition       = pure DefaultDisposition
+
 _mailHeader :: CI ByteString -> Traversal' Mail Text
 _mailHeader hdrName = _mailHeaders . traverse . filtered (views _1 $ (== hdrName) . CI.mk) . _2
 
@@ -328,7 +332,7 @@ instance YesodMail site => ToMailPart site LT.Text where
   toMailPart text = do
     _partType .= decodeUtf8 typePlain
     _partEncoding .= QuotedPrintableText
-    _partContent .= encodeUtf8 text
+    _partContent .= PartContent (encodeUtf8 text)
 
 instance YesodMail site => ToMailPart site Text where
   toMailPart = toMailPart . LT.fromStrict
@@ -340,7 +344,7 @@ instance YesodMail site => ToMailPart site Html where
   toMailPart html = do
     _partType .= decodeUtf8 typeHtml
     _partEncoding .= QuotedPrintableText
-    _partContent .= renderMarkup html
+    _partContent .= PartContent (renderMarkup html)
 
 instance (ToMailPart site a, RenderMessage site msg) => ToMailPart site (Hamlet.Translate msg -> a) where
   type MailPartReturn site (Hamlet.Translate msg -> a) = MailPartReturn site a
@@ -364,7 +368,7 @@ instance YesodMail site => ToMailPart site Aeson.Value where
   toMailPart val = do
     _partType .= decodeUtf8 typeJson
     _partEncoding .= QuotedPrintableText
-    _partContent .= Aeson.encodePretty val
+    _partContent .= PartContent (Aeson.encodePretty val)
 
 
 addAlternatives :: (MonadMail m)
@@ -400,9 +404,9 @@ initialPart :: Part
 initialPart = Part
   { partType = decodeUtf8 defaultMimeType
   , partEncoding = Base64
-  , partFilename = Nothing
+  , partDisposition = DefaultDisposition
   , partHeaders = []
-  , partContent = mempty
+  , partContent = PartContent mempty
   }
 
 modifyPart :: (MonadMail m, HandlerSite m ~ site, YesodMail site)
@@ -413,7 +417,7 @@ modifyPart = toMailPart
 partIsAttachment :: (Textual t, MonadMail m, HandlerSite m ~ site, YesodMail site)
                  => t
                  -> StateT Part m ()
-partIsAttachment (repack -> fName) = modifyPart $ _partFilename .= Just fName
+partIsAttachment (repack -> fName) = modifyPart $ _partDisposition .= AttachmentDisposition fName
 
 
 class MonadHandler m => MonadHeader m where
diff --git a/src/Model.hs b/src/Model.hs
index 3821126b6..48c5aa8db 100644
--- a/src/Model.hs
+++ b/src/Model.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving, UndecidableInstances #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving, UndecidableInstances, DeriveAnyClass #-}
 
 module Model
   ( module Model
@@ -14,13 +14,9 @@ import Database.Persist.TH.Directory
 import Model.Types hiding (_maxPoints, _passingPoints)
 import Cron.Types
 
-import Data.Aeson (Value)
-
-import Data.CaseInsensitive (CI, original)
+import Data.CaseInsensitive (original)
 import Data.CaseInsensitive.Instances ()
 
-import Utils.Message (MessageStatus)
-
 import Settings.Cluster (ClusterSettingsKey)
 
 import Text.Blaze (ToMarkup(..))
diff --git a/src/Model/Migration.hs b/src/Model/Migration.hs
index eda1a905a..4fd3bbd83 100644
--- a/src/Model/Migration.hs
+++ b/src/Model/Migration.hs
@@ -1,21 +1,17 @@
-{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE UndecidableInstances, GeneralizedNewtypeDeriving #-}
 
 module Model.Migration
   ( migrateAll
   , requiresMigration
   ) where
 
-import Utils (lastMaybe)
-
 import Import.NoModel
 import Model
 import Audit.Types
 import Model.Migration.Version
 import qualified Model.Migration.Types as Legacy
-import Data.Map (Map)
 import qualified Data.Map as Map
 
-import Data.Set ()
 import qualified Data.Set as Set
 
 import qualified Data.Text as Text
@@ -26,25 +22,15 @@ import Database.Persist.Sql
 import Database.Persist.Sql.Raw.QQ
 import Database.Persist.Postgresql
 
-import Control.Monad.Trans.Maybe (MaybeT(..))
-
 import Text.Read (readMaybe)
-import Data.CaseInsensitive (CI)
 
-import Text.Shakespeare.Text (st)
-
-import Control.Monad.Trans.Reader (mapReaderT)
 import Control.Monad.Except (MonadError(..))
-import Utils (exceptT, allM, whenIsJust, guardM)
 import Utils.Lens (_NoUpload)
-import Utils.DB (getKeyBy)
 
 import qualified Net.IP as IP
 import qualified Net.IPv4 as IPv4
 import qualified Net.IPv6 as IPv6
 
-import Data.Aeson (toJSON)
-
 import qualified Data.Char as Char
 import qualified Data.CaseInsensitive as CI
 
diff --git a/src/Model/Migration/Types.hs b/src/Model/Migration/Types.hs
index 58e6b7b25..69226bf76 100644
--- a/src/Model/Migration/Types.hs
+++ b/src/Model/Migration/Types.hs
@@ -2,7 +2,7 @@ module Model.Migration.Types where
 
 import ClassyPrelude.Yesod
 import Data.Aeson
-import Data.Aeson.TH (deriveJSON, defaultOptions)
+import Data.Aeson.TH (deriveJSON)
 
 import Utils.PathPiece
 
diff --git a/src/Model/Rating.hs b/src/Model/Rating.hs
index 0e2fcf8cb..62f593d49 100644
--- a/src/Model/Rating.hs
+++ b/src/Model/Rating.hs
@@ -4,8 +4,6 @@ import ClassyPrelude.Yesod
 import Model
 -- import Data.Text (Text)
 import Data.Text.Encoding.Error (UnicodeException(..))
-import GHC.Generics (Generic)
-import Data.Typeable (Typeable)
 
 
 data Rating = Rating
diff --git a/src/Model/Tokens.hs b/src/Model/Tokens.hs
index 5a2d6335e..613e5ce0d 100644
--- a/src/Model/Tokens.hs
+++ b/src/Model/Tokens.hs
@@ -1,3 +1,4 @@
+{-# OPTIONS_GHC -fno-warn-incomplete-uni-patterns #-}
 {-# LANGUAGE UndecidableInstances #-}
 
 module Model.Tokens
@@ -23,14 +24,12 @@ import qualified Jose.Jwt as Jose
 import Jose.Jwt.Instances ()
 import Data.Aeson.Types.Instances ()
 
-import Data.HashSet (HashSet)
-
 import qualified Data.HashMap.Strict as HashMap
 import Data.HashMap.Strict.Instances ()
 import Data.HashSet.Instances ()
 import Data.Time.Clock.Instances ()
 
-import Data.Aeson.Types (Parser, (.:?), (.:), (.!=), (.=))
+import Data.Aeson.Types (Parser, (.:?), (.!=))
 import qualified Data.Aeson as JSON
 import qualified Data.Aeson.Types as JSON
 
diff --git a/src/Model/Types/Allocation.hs b/src/Model/Types/Allocation.hs
index 7eca27b58..6fe299312 100644
--- a/src/Model/Types/Allocation.hs
+++ b/src/Model/Types/Allocation.hs
@@ -14,7 +14,7 @@ import qualified Data.Vector as Vector
 
 import qualified Data.Map.Strict as Map
   
-import Crypto.Hash (Digest, SHAKE128)
+import Crypto.Hash (SHAKE128)
 
 {-# ANN module ("HLint: ignore Use newtype instead of data"::String) #-}
 
diff --git a/src/Model/Types/DateTime.hs b/src/Model/Types/DateTime.hs
index cff7a0793..db1a8f9d7 100644
--- a/src/Model/Types/DateTime.hs
+++ b/src/Model/Types/DateTime.hs
@@ -1,3 +1,4 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
 {-|
 Module: Model.Types.DateTime
 Description: Time related types
@@ -20,9 +21,6 @@ import Web.HttpApiData
 
 import Data.Aeson.Types as Aeson
 
-import Time.Types (WeekDay(..))
-import Data.Time.LocalTime (LocalTime, TimeOfDay)
-
 
 ----
 --  Terms, Seaons, anything loosely related to time
@@ -42,6 +40,7 @@ seasonFromChar c
   | c ~= 'W'  = Right Winter
   | otherwise = Left $ "Invalid season character: ‘" <> tshow c <> "’"
   where
+    (~=) :: Char -> Char -> Bool
     (~=) = (==) `on` CI.mk
 
 data TermIdentifier = TermIdentifier
@@ -64,6 +63,7 @@ shortened :: Iso' Integer Integer
 -- ^ Year numbers shortened to two digits
 shortened = iso shorten expand
   where
+    century :: Integer
     century = ($currentYear `div` 100) * 100
     expand year
       | 0 <= year
@@ -189,3 +189,5 @@ deriveJSON defaultOptions
   } ''Occurrences
 derivePersistFieldJSON ''Occurrences
 
+
+nullaryPathPiece ''DayOfWeek camelToPathPiece
diff --git a/src/Model/Types/Exam.hs b/src/Model/Types/Exam.hs
index 8c05bb3cd..265686c14 100644
--- a/src/Model/Types/Exam.hs
+++ b/src/Model/Types/Exam.hs
@@ -231,6 +231,7 @@ instance Finite ExamGrade
 numberGrade :: Prism' Rational ExamGrade
 numberGrade = prism toNumberGrade fromNumberGrade
   where
+    toNumberGrade :: ExamGrade -> Rational
     toNumberGrade = \case
       Grade50 -> 5.0
       Grade40 -> 4.0
@@ -243,6 +244,7 @@ numberGrade = prism toNumberGrade fromNumberGrade
       Grade17 -> 1.7
       Grade13 -> 1.3
       Grade10 -> 1.0
+    fromNumberGrade :: Rational -> Either Rational ExamGrade
     fromNumberGrade = \case
       5.0 -> Right Grade50
       4.0 -> Right Grade40
@@ -271,7 +273,8 @@ instance Csv.FromField ExamGrade where
     [ parse =<< Csv.parseField x
     , parse . Text.replace "," "." =<< Csv.parseField x -- Ugh.
     ]
-    where parse = maybe (fail "Could not decode PathPiece") return . fromPathPiece
+    where parse :: Text -> Csv.Parser ExamGrade
+          parse = maybe (fail "Could not decode PathPiece") return . fromPathPiece
 
 instance PersistField ExamGrade where
   toPersistValue = PersistRational . review numberGrade
diff --git a/src/Model/Types/Mail.hs b/src/Model/Types/Mail.hs
index de71b226b..228427ac1 100644
--- a/src/Model/Types/Mail.hs
+++ b/src/Model/Types/Mail.hs
@@ -54,15 +54,9 @@ instance Finite NotificationTrigger
 
 instance Hashable NotificationTrigger
 
-deriveJSON defaultOptions
-  { constructorTagModifier = intercalate "-" . map toLower . drop 1 . splitCamel
-  } ''NotificationTrigger
-
-instance ToJSONKey NotificationTrigger where
-  toJSONKey = toJSONKeyText $ \v -> let Aeson.String t = toJSON v in t
-
-instance FromJSONKey NotificationTrigger where
-  fromJSONKey = FromJSONKeyTextParser $ parseJSON . Aeson.String
+nullaryPathPiece ''NotificationTrigger $ camelToPathPiece' 1
+pathPieceJSON ''NotificationTrigger
+pathPieceJSONKey ''NotificationTrigger
 
 
 newtype NotificationSettings = NotificationSettings { notificationAllowed :: NotificationTrigger -> Bool }
diff --git a/src/Model/Types/Misc.hs b/src/Model/Types/Misc.hs
index 7cddd01b0..ea7167d48 100644
--- a/src/Model/Types/Misc.hs
+++ b/src/Model/Types/Misc.hs
@@ -177,7 +177,7 @@ instance YesodMail site => ToMailPart site (CsvRendered, CsvOptions) where
   toMailPart (CsvRendered{..}, encOpts) = do
     _partType .= decodeUtf8 typeCsv'
     _partEncoding .= QuotedPrintableText
-    _partContent .= recode' (Csv.encodeByNameWith (encOpts ^. _csvFormat . _CsvEncodeOptions) csvRenderedHeader csvRenderedData)
+    _partContent .= PartContent (recode' $ Csv.encodeByNameWith (encOpts ^. _csvFormat . _CsvEncodeOptions) csvRenderedHeader csvRenderedData)
     where
       recode' :: LBS.ByteString -> LBS.ByteString
       recode'
@@ -218,14 +218,16 @@ deriveJSON defaultOptions
   } ''Sex
 nullaryPathPiece ''Sex $ camelToPathPiece' 1
 
-iso5218 :: Integral n => Prism' n Sex
+iso5218 :: forall n. Integral n => Prism' n Sex
 iso5218 = prism' sexToWord sexFromWord
   where
+    sexToWord :: Sex -> n
     sexToWord = \case
       SexNotKnown      -> 0
       SexMale          -> 1
       SexFemale        -> 2
       SexNotApplicable -> 9
+    sexFromWord :: n -> Maybe Sex
     sexFromWord = \case
       0 -> Just SexNotKnown
       1 -> Just SexMale
diff --git a/src/Model/Types/Security.hs b/src/Model/Types/Security.hs
index 682cbc789..3b5142bce 100644
--- a/src/Model/Types/Security.hs
+++ b/src/Model/Types/Security.hs
@@ -11,8 +11,6 @@ module Model.Types.Security
 
 import Import.NoModel
 
-import Data.Set (Set)
-
 import qualified Data.Text as Text
 
 import qualified Data.HashMap.Strict as HashMap
@@ -89,17 +87,9 @@ instance Universe AuthTag
 instance Finite AuthTag
 instance Hashable AuthTag
 
-deriveJSON defaultOptions
-  { constructorTagModifier = camelToPathPiece' 1
-  } ''AuthTag
-
-nullaryPathPiece ''AuthTag (camelToPathPiece' 1)
-
-instance ToJSONKey AuthTag where
-  toJSONKey = toJSONKeyText $ \v -> let Aeson.String t = toJSON v in t
-
-instance FromJSONKey AuthTag where
-  fromJSONKey = FromJSONKeyTextParser $ parseJSON . Aeson.String
+nullaryPathPiece ''AuthTag $ camelToPathPiece' 1
+pathPieceJSON ''AuthTag
+pathPieceJSONKey ''AuthTag
 
 instance Binary AuthTag
 
@@ -175,6 +165,7 @@ instance PathPiece UserGroupName where
     | "metrics" `ciEq` t -> UserGroupMetrics
     | otherwise          -> UserGroupCustom $ CI.mk t
     where
+      ciEq :: Text -> Text -> Bool
       ciEq = (==) `on` CI.mk
 
 pathPieceJSON ''UserGroupName
diff --git a/src/Model/Types/Sheet.hs b/src/Model/Types/Sheet.hs
index d545c5bbb..26e4bb291 100644
--- a/src/Model/Types/Sheet.hs
+++ b/src/Model/Types/Sheet.hs
@@ -13,15 +13,11 @@ import Utils.Lens.TH
 
 import Generics.Deriving.Monoid (memptydefault, mappenddefault)
 
-import Data.Set (Set)
 import qualified Data.Set as Set
 import qualified Data.Map as Map
-import Data.Aeson.TH (deriveJSON, defaultOptions, Options(..), SumEncoding(..))
 
 import Text.Blaze (Markup)
 
-import Yesod.Core.Dispatch (PathPiece(..))
-
 import Data.Maybe (fromJust)
 
 
diff --git a/src/Model/Types/Submission.hs b/src/Model/Types/Submission.hs
index 1c5e4655d..b8ace9549 100644
--- a/src/Model/Types/Submission.hs
+++ b/src/Model/Types/Submission.hs
@@ -11,7 +11,6 @@ module Model.Types.Submission
 
 import Import.NoModel
 
-import Data.Aeson.Types (ToJSON(..), FromJSON(..))
 import qualified Data.Aeson.Types as Aeson
 
 import Database.Persist.Sql
@@ -142,6 +141,7 @@ pseudonymWords = folding
   where
     distance = damerauLevenshtein `on` CI.foldedCase
     -- | Arbitrary cutoff point, for reference: ispell cuts off at 1
+    distanceCutoff :: Int
     distanceCutoff = 2
 
 pseudonymFragments :: Fold Text [PseudonymWord]
diff --git a/src/Model/Types/TH/Wordlist.hs b/src/Model/Types/TH/Wordlist.hs
index de3d159d8..7ef389c0e 100644
--- a/src/Model/Types/TH/Wordlist.hs
+++ b/src/Model/Types/TH/Wordlist.hs
@@ -7,7 +7,6 @@ import ClassyPrelude hiding (lift)
 import Language.Haskell.TH
 import Language.Haskell.TH.Syntax (qAddDependentFile, Lift(..))
 
-import Data.Text (Text)
 import qualified Data.Text as Text
 import qualified Data.Text.IO as Text
 
diff --git a/src/Network/Mail/Mime/Instances.hs b/src/Network/Mail/Mime/Instances.hs
index 83cc59c14..201442aee 100644
--- a/src/Network/Mail/Mime/Instances.hs
+++ b/src/Network/Mail/Mime/Instances.hs
@@ -6,7 +6,6 @@ module Network.Mail.Mime.Instances
 
 import ClassyPrelude
 import Network.Mail.Mime
-import Data.Hashable (Hashable)
 
 import Data.Aeson
 import Data.Aeson.TH
diff --git a/src/Network/Mime/TH.hs b/src/Network/Mime/TH.hs
index 486eda779..e90033904 100644
--- a/src/Network/Mime/TH.hs
+++ b/src/Network/Mime/TH.hs
@@ -9,7 +9,6 @@ import Language.Haskell.TH.Syntax (qAddDependentFile, Lift(..))
 import qualified Data.Set as Set
 import qualified Data.Map as Map
 
-import Data.Text (Text)
 import qualified Data.Text as Text
 import qualified Data.Text.IO as Text
 import qualified Data.Text.Encoding as Text
diff --git a/src/Settings.hs b/src/Settings.hs
index 76dea50e7..a611d19b9 100644
--- a/src/Settings.hs
+++ b/src/Settings.hs
@@ -13,7 +13,6 @@ module Settings
   ) where
 
 import           Import.NoModel
-import Data.UUID (UUID)
 import qualified Control.Exception           as Exception
 import           Data.Aeson                  (fromJSON, withObject
                                              ,(.!=), (.:?), withScientific
@@ -23,12 +22,10 @@ import           Data.FileEmbed              (embedFile)
 import           Data.Yaml                   (decodeEither')
 import           Database.Persist.Postgresql (PostgresConf)
 import           Network.Wai.Handler.Warp    (HostPreference)
-import           Yesod.Default.Config2       (applyEnvValue, configSettingsYml)
 #ifdef DEVELOPMENT
 import           Yesod.Default.Util          (WidgetFileSettings, widgetFileReload)
 import           Language.Haskell.TH.Syntax  (Exp, Q, location, Loc(..))
 
-import Text.Shakespeare.Text (st)
 import Text.Blaze.Html (preEscapedToHtml)
 #else
 import           Yesod.Default.Util          (WidgetFileSettings, widgetFileNoReload, widgetFileReload)
@@ -36,8 +33,6 @@ import           Language.Haskell.TH.Syntax  (Exp, Q)
 #endif
 import qualified Yesod.Auth.Util.PasswordStore as PWStore
 
-import Data.Time (NominalDiffTime, nominalDay)
-
 import Data.Scientific (Scientific, toBoundedInteger)
 import Data.Word (Word16)
 
@@ -47,22 +42,16 @@ import qualified Data.Text.Encoding as Text
 import qualified Ldap.Client as Ldap
 
 import qualified Network.HaskellNet.Auth as HaskellNet (UserName, Password, AuthType(..))
-import qualified Network.Socket as HaskellNet (PortNumber, HostName)
-import qualified Network
+import qualified Network.Socket as HaskellNet
 
-import Network.Mail.Mime (Address)
 import Network.Mail.Mime.Instances ()
 
-import Mail (VerpMode)
-
 import qualified Database.Memcached.Binary.Types as Memcached
 
 import Model
 import Settings.Cluster
 import Settings.Mime
 
-import Control.Monad.Trans.Maybe (MaybeT(..))
-
 import qualified System.FilePath as FilePath
 
 import Jose.Jwt (JwtEncoding(..))
@@ -230,13 +219,6 @@ data WidgetMemcachedConf = WidgetMemcachedConf
 instance FromJSON Memcached.Auth where
   parseJSON = Aeson.withText "Auth" $ \(Text.breakOn "@" -> (encodeUtf8 -> user, encodeUtf8 -> pw)) -> return $ Memcached.Plain user pw
 
-instance FromJSON Network.PortID where
-  parseJSON v = Network.UnixSocket <$> pSocket v <|> Network.PortNumber <$> pNumber v <|> Network.Service <$> pService v
-    where
-      pSocket = Aeson.withText "UnixSocket" $ fmap unpack . assertM' ("/" `Text.isPrefixOf`)
-      pNumber = Aeson.withScientific "PortNumber" $ maybe (fail "PortNumber ") (return . (fromIntegral :: Word16 -> Network.PortNumber)) . toBoundedInteger
-      pService = Aeson.withText "Service" $ return . unpack
-
 instance FromJSON WidgetMemcachedConf where
   parseJSON = withObject "WidgetMemcachedConf" $ \o -> do
     connectHost <- o .:? "host" .!= ""
@@ -382,13 +364,11 @@ instance FromJSON AppSettings where
         appLdapConf               <- assertM nonEmptyHost <$> o .:? "ldap"
         appSmtpConf               <- assertM (not . null . smtpHost) <$> o .:? "smtp"
         let validWidgetMemcachedConf WidgetMemcachedConf{ widgetMemcachedConnectInfo = Memcached.ConnectInfo{..}, ..} = and
-              [ not (null connectHost) || isUnixSocket connectPort
+              [ not $ null connectHost
               , not $ null widgetMemcachedBaseUrl
               , numConnection > 0
               , connectionIdleTime >= 0
               ]
-            isUnixSocket (Network.UnixSocket _) = True
-            isUnixSocket _ = False
         appWidgetMemcachedConf    <- assertM validWidgetMemcachedConf <$> o .:? "widget-memcached"
         appRoot                   <- o .:? "approot"
         appHost                   <- fromString <$> o .: "host"
diff --git a/src/Settings/Cluster.hs b/src/Settings/Cluster.hs
index 037c9d967..6b4d0e836 100644
--- a/src/Settings/Cluster.hs
+++ b/src/Settings/Cluster.hs
@@ -6,19 +6,12 @@ module Settings.Cluster
   ) where
 
 import ClassyPrelude.Yesod
-import Database.Persist.Sql
 import Web.HttpApiData
 
 import Utils
 import Control.Lens
 import Data.Universe
 
-import Data.Aeson ( FromJSON(..), ToJSON(..)
-                  , Options(..), defaultOptions
-                  , FromJSONKey(..), ToJSONKey(..), FromJSONKeyFunction(..)
-                  )
-import Data.Aeson.TH (deriveJSON)
-import Data.Aeson.Types (toJSONKeyText)
 import qualified Data.Aeson as Aeson
 
 import qualified Web.ClientSession as ClientSession
@@ -39,6 +32,10 @@ import qualified Jose.Jwt as Jose
 import Data.UUID (UUID)
 import Control.Monad.Random.Class (MonadRandom(..))
 
+import Control.Monad.Fail
+
+import Model.Types.TH.PathPiece
+
 
 data ClusterSettingsKey
   = ClusterCryptoIDKey
@@ -51,27 +48,10 @@ data ClusterSettingsKey
 instance Universe ClusterSettingsKey
 instance Finite ClusterSettingsKey
 
-nullaryPathPiece ''ClusterSettingsKey (camelToPathPiece' 1)
-
-deriveJSON
-  defaultOptions
-    { constructorTagModifier = camelToPathPiece' 1
-    }
-  ''ClusterSettingsKey
-
-instance ToJSONKey ClusterSettingsKey where
-  toJSONKey = toJSONKeyText $ \v -> let String t = toJSON v in t
-
-instance FromJSONKey ClusterSettingsKey where
-  fromJSONKey = FromJSONKeyTextParser $ parseJSON . String
-
-instance PersistField ClusterSettingsKey where
-  toPersistValue = PersistText . toPathPiece
-  fromPersistValue (PersistText t) = maybe (Left $ "Could not parse " <> t) Right $ fromPathPiece t
-  fromPersistValue _other = Left "Expecting PersistText"
-
-instance PersistFieldSql ClusterSettingsKey where
-  sqlType _ = SqlString
+nullaryPathPiece ''ClusterSettingsKey $ camelToPathPiece' 1
+pathPieceJSON ''ClusterSettingsKey
+pathPieceJSONKey ''ClusterSettingsKey
+derivePersistFieldPathPiece ''ClusterSettingsKey
 
 instance ToHttpApiData ClusterSettingsKey where
   toUrlPiece = toPathPiece
diff --git a/src/Settings/StaticFiles/Generator.hs b/src/Settings/StaticFiles/Generator.hs
index 2e2d0ae45..47c04090c 100644
--- a/src/Settings/StaticFiles/Generator.hs
+++ b/src/Settings/StaticFiles/Generator.hs
@@ -25,6 +25,8 @@ import qualified Data.Foldable as Fold
 
 import Settings.Mime
 
+import Control.Monad.Fail
+
 
 staticGenerator :: FilePath -> Generator
 staticGenerator staticDir = do
diff --git a/src/Settings/WellKnownFiles/TH.hs b/src/Settings/WellKnownFiles/TH.hs
index 890184588..e88a25755 100644
--- a/src/Settings/WellKnownFiles/TH.hs
+++ b/src/Settings/WellKnownFiles/TH.hs
@@ -26,17 +26,18 @@ import qualified Data.Set as Set
 
 import Data.List.NonEmpty (NonEmpty(..))
 
-import Data.HashMap.Strict (HashMap)
 import qualified Data.HashMap.Strict as HashMap
 
 import qualified Data.HashSet as HashSet
 
-import System.FilePath ((</>), splitDirectories, makeRelative)
+import System.FilePath (splitDirectories, makeRelative)
 
 import Settings.Mime
 
 import Text.Blaze.Html (preEscapedToHtml)
 
+import Control.Monad.Fail
+
 nWellKnownFileName :: Name
 nWellKnownFileName = mkName "WellKnownFileName"
 
diff --git a/src/Text/Blaze/Instances.hs b/src/Text/Blaze/Instances.hs
index 3ff06308b..19c479aa9 100644
--- a/src/Text/Blaze/Instances.hs
+++ b/src/Text/Blaze/Instances.hs
@@ -10,7 +10,6 @@ import qualified Text.Blaze.Renderer.Text as Text
 
 import Text.Read (Read(..))
 
-import Data.Hashable (Hashable(..))
 import Data.Aeson (ToJSON(..), FromJSON(..))
 import qualified Data.Aeson as Aeson
 
diff --git a/src/Time/Types/Instances.hs b/src/Time/Types/Instances.hs
deleted file mode 100644
index fa61bca45..000000000
--- a/src/Time/Types/Instances.hs
+++ /dev/null
@@ -1,25 +0,0 @@
-{-# OPTIONS_GHC -fno-warn-orphans #-}
-
-module Time.Types.Instances
-  (
-  ) where
-
--- import ClassyPrelude
-
-import Time.Types
-
-import Data.Universe
-
-import Utils.PathPiece
-
-import Data.Aeson.TH
-
-
-instance Universe WeekDay
-instance Finite WeekDay
-
-nullaryPathPiece ''WeekDay camelToPathPiece
-
-deriveJSON defaultOptions
-  { constructorTagModifier = camelToPathPiece
-  } ''WeekDay
diff --git a/src/Utils.hs b/src/Utils.hs
index c1a05222d..56809e75d 100644
--- a/src/Utils.hs
+++ b/src/Utils.hs
@@ -35,9 +35,7 @@ import Text.Blaze (Markup, ToMarkup)
 import Data.Char (isDigit, isSpace, isAscii)
 import Data.Text (dropWhileEnd, takeWhileEnd, justifyRight)
 
-import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Map (Map)
 import qualified Data.Map as Map
 import qualified Data.List as List
 
@@ -204,7 +202,7 @@ textPercent' trailZero precision part whole
 
 
 -- | Convert number of bytes to human readable format
-textBytes :: Integral a => a -> Text
+textBytes :: forall a. Integral a => a -> Text
 textBytes x
   | v < kb    = rshow  v     <>  "B"
   | v < mb    = rshow (v/kb) <> "KB"
@@ -212,6 +210,7 @@ textBytes x
   | otherwise = rshow (v/gb) <> "GB"
  where
   v  = fromIntegral x
+  kb :: Double
   kb = 1024
   mb = 1024 * kb
   gb = 1024 * mb
diff --git a/src/Utils/Allocation.hs b/src/Utils/Allocation.hs
index d5e80c6b4..ffdd3684d 100644
--- a/src/Utils/Allocation.hs
+++ b/src/Utils/Allocation.hs
@@ -14,7 +14,6 @@ import Data.Array.ST (STArray)
 import qualified Data.Array.MArray as MArr
 
 import System.Random (RandomGen)
-import Control.Monad.Random.Class (getRandom)
 import Control.Monad.Trans.Random.Strict (evalRandT, RandT)
 import Control.Monad.Trans.State.Strict (StateT, modify', get, gets, evalStateT)
 import Control.Monad.Writer (tell)
@@ -45,7 +44,6 @@ computeMatching :: forall randomGen student course cloneCount cloneIndex capacit
                    , Ord student, Ord course
                    , NFData student
                    , Ord studentRatingCourse
-                   , Ord courseRatingStudent
                    , Ord courseRatingStudent'
                    , Integral cloneCount, Integral capacity, Num cloneIndex
                    )
@@ -63,7 +61,6 @@ computeMatchingLog :: forall randomGen student course cloneCount cloneIndex capa
                       , Ord student, Ord course
                       , NFData student
                       , Ord studentRatingCourse
-                      , Ord courseRatingStudent
                       , Ord courseRatingStudent'
                       , Integral cloneCount, Integral capacity, Num cloneIndex
                       )
diff --git a/src/Utils/DB.hs b/src/Utils/DB.hs
index decb7e4d6..fffdc8c51 100644
--- a/src/Utils/DB.hs
+++ b/src/Utils/DB.hs
@@ -3,9 +3,7 @@ module Utils.DB where
 import ClassyPrelude.Yesod
 
 import qualified Data.List as List
-import Data.Map (Map)
 import qualified Data.Map as Map
-import Data.Set (Set)
 import qualified Data.Set as Set
 import qualified Database.Esqueleto as E
 -- import Database.Persist -- currently not needed here
diff --git a/src/Utils/DateTime.hs b/src/Utils/DateTime.hs
index 3120f49f5..29861dfc8 100644
--- a/src/Utils/DateTime.hs
+++ b/src/Utils/DateTime.hs
@@ -15,7 +15,7 @@ module Utils.DateTime
 import ClassyPrelude.Yesod hiding (lift)
 import System.Locale.Read
 
-import Data.Time (TimeLocale(..), NominalDiffTime, nominalDay)
+import Data.Time (NominalDiffTime, nominalDay)
 import Data.Time.Zones (TZ)
 import Data.Time.Zones.TH (includeSystemTZ)
 
@@ -26,14 +26,9 @@ import Language.Haskell.TH.Syntax (Lift(..))
 import Instances.TH.Lift ()
 
 import Data.Data (Data)
-import Data.Typeable (Typeable)
 import Data.Universe
 
-import Database.Persist.Sql (PersistField, PersistFieldSql)
-
-import Data.Aeson.Types (toJSONKeyText)
-import Data.Aeson
-import Data.Aeson.TH
+import Database.Persist.Sql (PersistFieldSql)
 
 import Utils.PathPiece
 
@@ -41,6 +36,8 @@ import Data.Time.Format.Instances ()
 
 import Algebra.Lattice
 import Algebra.Lattice.Ordered
+
+import Control.Monad.Fail
   
 
 -- $(timeLocaleMap _) :: [Lang] -> TimeLocale
@@ -89,36 +86,25 @@ instance Universe SelDateTimeFormat
 instance Finite SelDateTimeFormat
 instance Hashable SelDateTimeFormat
 
-deriveJSON defaultOptions
-  { constructorTagModifier = camelToPathPiece' 2
-  } ''SelDateTimeFormat
-
-instance ToJSONKey SelDateTimeFormat where
-  toJSONKey = toJSONKeyText $ \v -> let String txt = toJSON v in txt
-instance FromJSONKey SelDateTimeFormat where
-  fromJSONKey = FromJSONKeyTextParser $ parseJSON . String
+nullaryPathPiece ''SelDateTimeFormat $ camelToPathPiece' 2
+pathPieceJSON ''SelDateTimeFormat
+pathPieceJSONKey ''SelDateTimeFormat
 
 instance {-# OVERLAPPING #-} Default (SelDateTimeFormat -> DateTimeFormat) where
   def SelFormatDateTime = "%c"
   def SelFormatDate     = "%F"
   def SelFormatTime     = "%T"
 
-instance JoinSemiLattice SelDateTimeFormat where
+instance Lattice SelDateTimeFormat where
   a \/ b = getOrdered $ ((\/) `on` Ordered) a b
-
-instance MeetSemiLattice SelDateTimeFormat where
   a /\ b = getOrdered $ ((/\) `on` Ordered) a b
 
-instance Lattice SelDateTimeFormat
-
 instance BoundedJoinSemiLattice SelDateTimeFormat where
   bottom = SelFormatTime
   
 instance BoundedMeetSemiLattice SelDateTimeFormat where
   top = SelFormatDateTime
 
-instance BoundedLattice SelDateTimeFormat
-
 
 ---------------------
 -- NominalDiffTime --
diff --git a/src/Utils/Form.hs b/src/Utils/Form.hs
index 4fa7681b5..1c37049fa 100644
--- a/src/Utils/Form.hs
+++ b/src/Utils/Form.hs
@@ -24,7 +24,6 @@ import Data.Map.Lazy ((!))
 import qualified Data.Map.Lazy as Map
 import qualified Data.Set as Set
 
-import Control.Monad.Trans.Maybe (MaybeT(..))
 import Control.Monad.Reader.Class (MonadReader(..))
 import Control.Monad.Writer.Class (MonadWriter(..), censor)
 import Control.Monad.State.Class (MonadState(..))
@@ -482,7 +481,7 @@ reorderField optList = Field{..}
           return (i, val)
       return $ if
         | Map.keysSet selOptions == Set.fromList [1..olNum]
-          -> Right . Just $ map (selOptions !) [1..fromIntegral olNum]
+          -> Right . Just $ map (selOptions !) [1..olNum]
         | otherwise
           -> Left "Not a valid permutation"
     fieldView theId name attrs val isReq = do
diff --git a/src/Utils/Lang.hs b/src/Utils/Lang.hs
index 3280c62fc..d99c909b3 100644
--- a/src/Utils/Lang.hs
+++ b/src/Utils/Lang.hs
@@ -11,7 +11,7 @@ import qualified Data.List as List
 
 import qualified Data.CaseInsensitive as CI
 
-import Yesod.Core.Types (HandlerData(handlerRequest), YesodRequest(reqLangs))
+import Yesod.Core.Types (HandlerData(handlerRequest))
 import qualified Network.Wai.Parse as NWP
 
 import Control.Monad.Trans.Maybe (MaybeT(..))
diff --git a/src/Utils/Lens.hs b/src/Utils/Lens.hs
index 1e5042171..af91720e8 100644
--- a/src/Utils/Lens.hs
+++ b/src/Utils/Lens.hs
@@ -21,7 +21,7 @@ import Data.Map.Lens as Utils.Lens
 
 import Data.Generics.Product.Types as Utils.Lens
 
-import Yesod.Core.Types (HandlerContents(..), ErrorResponse(..))
+import Yesod.Core.Types (HandlerContents(..))
 
 import qualified Database.Esqueleto as E (Value(..),InnerJoin(..))
 
diff --git a/src/Utils/Occurrences.hs b/src/Utils/Occurrences.hs
index 28ebdab8d..6b4051d89 100644
--- a/src/Utils/Occurrences.hs
+++ b/src/Utils/Occurrences.hs
@@ -10,7 +10,7 @@ import Model.Types
 import Utils
 import Utils.Lens
 
-import Control.Monad.Trans.Reader (runReader, Reader)
+import Control.Monad.Trans.Reader (runReader)
 
 import Control.Monad.Trans.Except (ExceptT, throwE, runExceptT)
 
diff --git a/src/Utils/PathPiece.hs b/src/Utils/PathPiece.hs
index f3b8e0e7b..1ce2b0a94 100644
--- a/src/Utils/PathPiece.hs
+++ b/src/Utils/PathPiece.hs
@@ -26,6 +26,8 @@ import Data.List (foldl)
 
 import Data.Aeson.Types
 import qualified Data.Aeson.Types as Aeson
+
+import Control.Monad.Fail
   
 
 finiteFromPathPiece :: (PathPiece a, Finite a) => Text -> Maybe a
diff --git a/src/Utils/SystemMessage.hs b/src/Utils/SystemMessage.hs
index e5cff0496..8de3add92 100644
--- a/src/Utils/SystemMessage.hs
+++ b/src/Utils/SystemMessage.hs
@@ -5,8 +5,6 @@ import Import.NoFoundation
 import qualified Data.List.NonEmpty as NonEmpty
 import Data.List (findIndex)
 
-import Control.Monad.Trans.Maybe (MaybeT(..))
-
 
 getSystemMessage :: MonadHandler m
                  => NonEmpty Lang -- ^ `appLanguages`
diff --git a/src/Utils/TH.hs b/src/Utils/TH.hs
index be7d53957..9855daeb6 100644
--- a/src/Utils/TH.hs
+++ b/src/Utils/TH.hs
@@ -13,6 +13,8 @@ import Language.Haskell.TH.Datatype
 
 import Data.List ((!!), foldl)
 
+import Control.Monad.Fail
+
 ------------
 -- Tuples --
 ------------
diff --git a/src/Utils/Tokens.hs b/src/Utils/Tokens.hs
index 549ea81e6..5ae042c82 100644
--- a/src/Utils/Tokens.hs
+++ b/src/Utils/Tokens.hs
@@ -8,9 +8,6 @@ module Utils.Tokens
 
 import Import.NoModel
 
-import Yesod.Auth (AuthId)
-
-import Utils (NTop(..), hoistMaybe, SessionKey(..))
 import Utils.Lens
 
 import Model
@@ -28,9 +25,6 @@ import qualified Data.Aeson.Internal as JSON (iparse, formatError)
 
 import qualified Data.HashMap.Strict as HashMap
 
-import Control.Monad.Random (MonadRandom(..))
-import Control.Monad.Trans.Maybe (MaybeT(..))
-
 import Settings
 
 import CryptoID
diff --git a/src/Yesod/Core/Instances.hs b/src/Yesod/Core/Instances.hs
index 10c369666..e145d6575 100644
--- a/src/Yesod/Core/Instances.hs
+++ b/src/Yesod/Core/Instances.hs
@@ -12,20 +12,18 @@ import Control.Lens
 
 import Data.ByteString.Builder (toLazyByteString)
 
-import System.FilePath ((</>))
-
 import Data.Aeson
 import Data.Aeson.Types
 
 import Control.Monad.Fix
-import Control.Monad.Fail (MonadFail)
-import qualified Control.Monad.Fail as MonadFail
 import Control.Monad.Except (MonadError(..))
 import Data.Functor.Extend
 
 import Data.Binary (Binary)
 import qualified Data.Binary as Binary
 
+import Control.Monad.Fail
+
 
 routeFromPathPiece :: ParseRoute site => Text -> Maybe (Route site)
 routeFromPathPiece
@@ -77,8 +75,6 @@ instance Monad FormResult where
   FormMissing        >>= _ = FormMissing
   (FormFailure errs) >>= _ = FormFailure errs
 
-  fail = MonadFail.fail
-
 instance MonadFail FormResult where
   fail _ = FormMissing
 
diff --git a/src/Yesod/Core/Types/Instances.hs b/src/Yesod/Core/Types/Instances.hs
index faac3b4a3..042255544 100644
--- a/src/Yesod/Core/Types/Instances.hs
+++ b/src/Yesod/Core/Types/Instances.hs
@@ -22,7 +22,7 @@ import Utils
 import Language.Haskell.TH
 
 import Control.Monad.Reader (MonadReader(..))
-import Control.Monad.Trans.Reader (ReaderT, mapReaderT, runReaderT)
+import Control.Monad.Trans.Reader (mapReaderT)
 import Control.Monad.Base (MonadBase)
 import Control.Monad.Trans.Control (MonadBaseControl)
 import Control.Monad.Catch (MonadMask, MonadCatch)
diff --git a/stack.yaml b/stack.yaml
index d52b84385..20c318374 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -12,15 +12,24 @@ packages:
 
 extra-deps:
   - git: git@gitlab2.rz.ifi.lmu.de:uni2work/encoding.git
-    commit: 67bb87ceff53f0178c988dd4e15eeb2daee92b84
+    commit: 22fc3bb14841d8d50997aa47f1be3852e666f787
   - git: git@gitlab2.rz.ifi.lmu.de:uni2work/memcached-binary.git
-    commit: b5461747e7be226d3b67daebc3c9aefe8a4490ad
+    commit: b7071df50bad3a251a544b984e4bf98fa09b8fae
   - git: git@gitlab2.rz.ifi.lmu.de:uni2work/conduit-resumablesink.git
     commit: cbea6159c2975d42f948525e03e12fc390da53c5
+  - git: git://github.com/jtdaugherty/HaskellNet.git
+    commit: 5aa1f3b009253b02c4822005ac59ee208a10a347
+  - git: git@gitlab2.rz.ifi.lmu.de:uni2work/HaskellNet-SSL.git
+    commit: 40393c938111ac78232dc2c7eec5edb4a22d03e8
+  - git: git@gitlab2.rz.ifi.lmu.de:uni2work/ldap-client.git
+    commit: 01afaf599ba6f8a9d804c269e91d3190b249d3f0
 
-  - zip-stream-0.2.0.1
+  - colonnade-1.2.0.2
+  - hsass-0.8.0
+  - hlibsass-0.1.8.1
+  - tz-0.1.3.3
 
-  - ldap-client-0.3.0
+  # - zip-stream-0.2.0.1
 
   - uuid-crypto-1.4.0.0
   - filepath-crypto-0.1.0.0
@@ -34,55 +43,54 @@ extra-deps:
 
   - pkcs7-1.0.0.1
 
-  - systemd-1.2.0
+  - systemd-2.2.0
 
-  - directory-1.3.4.0
+  # - directory-1.3.4.0
 
-  - HaXml-1.25.5
+  # - HaXml-1.25.5
 
-  - persistent-2.10.4
-  - persistent-postgresql-2.10.1
-  - persistent-template-2.7.3
-  - esqueleto-3.2.3
+  # - persistent-2.10.4
+  # - persistent-postgresql-2.10.1
+  # - persistent-template-2.7.3
+  # - esqueleto-3.2.3
 
-  - HaskellNet-SSL-0.3.4.1
   - sandi-0.5
   - storable-endian-0.2.6
-  - universe-1.2
-  - universe-base-1.1.1
-  - universe-reverse-instances-1.1
-  - unliftio-pool-0.2.1.0
-  - universe-instances-extended-1.1.1
-  - universe-some-1.2
-  - some-1.0.0.3
+  # - universe-1.2
+  # - universe-base-1.1.1
+  # - universe-reverse-instances-1.1
+  # - unliftio-pool-0.2.1.0
+  # - universe-instances-extended-1.1.1
+  # - universe-some-1.2
+  # - some-1.0.0.3
 
-  - network-bsd-2.8.1.0
+  # - network-bsd-2.8.1.0
 
-  - persistent-qq-2.9.1
+  # - persistent-qq-2.9.1
 
-  - process-1.6.5.1
+  # - process-1.6.5.1
 
-  - generic-lens-1.2.0.0
+  # - generic-lens-1.2.0.0
 
-  - prometheus-metrics-ghc-1.0.0
+  - prometheus-metrics-ghc-1.0.1
   - wai-middleware-prometheus-1.0.0
 
-  - extended-reals-0.2.3.0
+  # - extended-reals-0.2.3.0
 
   - pandoc-2.9.2
   - doclayout-0.3
-  - emojis-0.1
-  - hslua-module-system-0.2.1
-  - ipynb-0.1
-  - jira-wiki-markup-1.0.0
-  - HsYAML-0.2.1.0
-  - cmark-gfm-0.2.1
   - doctemplates-0.8.1
-  - haddock-library-1.8.0
-  - pandoc-types-1.20
-  - skylighting-0.8.3.2
-  - skylighting-core-0.8.3.2
-  - texmath-0.12.0.1
+  # - emojis-0.1
+  # - hslua-module-system-0.2.1
+  # - ipynb-0.1
+  # - jira-wiki-markup-1.0.0
+  # - HsYAML-0.2.1.0
+  # - cmark-gfm-0.2.1
+  # - haddock-library-1.8.0
+  # - pandoc-types-1.20
+  # - skylighting-0.8.3.2
+  # - skylighting-core-0.8.3.2
+  # - texmath-0.12.0.1
 
-resolver: lts-13.21
+resolver: lts-15.0
 allow-newer: true
diff --git a/stack.yaml.lock b/stack.yaml.lock
index b96e82ebb..ecf90088b 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -6,32 +6,32 @@
 packages:
 - completed:
     cabal-file:
-      size: 4141
-      sha256: 88537113b855381b8d70da2442ae644dc979ad6b32aaaec2ebf55306764c8f1a
+      size: 4229
+      sha256: 0dcfe3c4a67be4e96e1ae2e3c4b8744bc11e094853005a32f6074ab776caa3a9
     name: encoding
     version: 0.8.2
     git: git@gitlab2.rz.ifi.lmu.de:uni2work/encoding.git
     pantry-tree:
-      size: 5668
-      sha256: 57160d758802aba6a0d2cc88c53f2f0bb60df7d5e6822938351618b7eca0beab
-    commit: 67bb87ceff53f0178c988dd4e15eeb2daee92b84
+      size: 5723
+      sha256: fec12328951021bb4d9326ae0b35f0c459e65f28442366efd4366cd1e18abe19
+    commit: 22fc3bb14841d8d50997aa47f1be3852e666f787
   original:
     git: git@gitlab2.rz.ifi.lmu.de:uni2work/encoding.git
-    commit: 67bb87ceff53f0178c988dd4e15eeb2daee92b84
+    commit: 22fc3bb14841d8d50997aa47f1be3852e666f787
 - completed:
     cabal-file:
-      size: 2384
-      sha256: 7b25a0ef819e8a01b485d6d0865baa3445faa826ffb3876c94109dd2469ffbd3
+      size: 2399
+      sha256: 20cdf97602abb8fd7356c1a64c69fa857e34ab4cfe7834460d2ad783f7e4e4e3
     name: memcached-binary
     version: 0.2.0
     git: git@gitlab2.rz.ifi.lmu.de:uni2work/memcached-binary.git
     pantry-tree:
-      size: 1170
-      sha256: c466f91129410bae1f53e25aec4026f6984ce2dff0ada4516e2548048aba549a
-    commit: b5461747e7be226d3b67daebc3c9aefe8a4490ad
+      size: 1277
+      sha256: 0da0539b7b9a56d03a116dcd666bc1bbbef085659910420849484d1418aa0857
+    commit: b7071df50bad3a251a544b984e4bf98fa09b8fae
   original:
     git: git@gitlab2.rz.ifi.lmu.de:uni2work/memcached-binary.git
-    commit: b5461747e7be226d3b67daebc3c9aefe8a4490ad
+    commit: b7071df50bad3a251a544b984e4bf98fa09b8fae
 - completed:
     cabal-file:
       size: 1423
@@ -47,19 +47,75 @@ packages:
     git: git@gitlab2.rz.ifi.lmu.de:uni2work/conduit-resumablesink.git
     commit: cbea6159c2975d42f948525e03e12fc390da53c5
 - completed:
-    hackage: zip-stream-0.2.0.1@sha256:78cd3244efbfba99184d17f5923980282f7d1b8f6d71c6e8af14e516e4239691,1742
+    cabal-file:
+      size: 2069
+      sha256: 9192ac19ea5da3cd4b8c86a4266592aff7b9256311aa5f42ae6de94ccacf1366
+    name: HaskellNet
+    version: 0.5.1
+    git: git://github.com/jtdaugherty/HaskellNet.git
     pantry-tree:
-      size: 559
-      sha256: 85960a435d280e933f697163c2ec6861261214d56f4c326d1ab920f37cb4f8c1
+      size: 4011
+      sha256: 921b437ef18ccb04f889301c407263d6b5b72c5864803a000b1e61328988ce70
+    commit: 5aa1f3b009253b02c4822005ac59ee208a10a347
   original:
-    hackage: zip-stream-0.2.0.1
+    git: git://github.com/jtdaugherty/HaskellNet.git
+    commit: 5aa1f3b009253b02c4822005ac59ee208a10a347
 - completed:
-    hackage: ldap-client-0.3.0@sha256:e62aa1cbe7fc27fc2f197c9cf3601c2fd46e189f8cd84bd25f8323537d31067f,2220
+    cabal-file:
+      size: 1934
+      sha256: 9fbe7c3681e963eea213ab38be17966bb690788c1c55a67257916b677d7d2ec2
+    name: HaskellNet-SSL
+    version: 0.3.4.1
+    git: git@gitlab2.rz.ifi.lmu.de:uni2work/HaskellNet-SSL.git
     pantry-tree:
-      size: 1717
-      sha256: 4a682a32028e18a60397d347666fe796e85ef3ba2365c1b5d03cfdd694f0711b
+      size: 841
+      sha256: 95dcec22fdb8af986e59f0f60aa76d4a48f34a546dca799bd571e1d183f773e0
+    commit: 40393c938111ac78232dc2c7eec5edb4a22d03e8
   original:
-    hackage: ldap-client-0.3.0
+    git: git@gitlab2.rz.ifi.lmu.de:uni2work/HaskellNet-SSL.git
+    commit: 40393c938111ac78232dc2c7eec5edb4a22d03e8
+- completed:
+    cabal-file:
+      size: 2208
+      sha256: 48f6e03d8f812bd24e2601497ffe9c8a78907fa2266ba05abeefdfe99221617d
+    name: ldap-client
+    version: 0.4.0
+    git: git@gitlab2.rz.ifi.lmu.de:uni2work/ldap-client.git
+    pantry-tree:
+      size: 6176
+      sha256: 3fa8f102427b437b2baaec15cf884e88b47a1621b1c3fd4d8919f0263fde8656
+    commit: 01afaf599ba6f8a9d804c269e91d3190b249d3f0
+  original:
+    git: git@gitlab2.rz.ifi.lmu.de:uni2work/ldap-client.git
+    commit: 01afaf599ba6f8a9d804c269e91d3190b249d3f0
+- completed:
+    hackage: colonnade-1.2.0.2@sha256:c95c2ecff5cfa28c736d8fa662d28b71129f67457068e3f4467b296a621607ab,2099
+    pantry-tree:
+      size: 327
+      sha256: 98ccdd327916e0ff0ea2fa93ff9a96f5d492ae88258b330e991e6dcc4d332496
+  original:
+    hackage: colonnade-1.2.0.2
+- completed:
+    hackage: hsass-0.8.0@sha256:82d55fb2a10342accbc4fe80d263163f40a138d8636e275aa31ffa81b14abf01,2792
+    pantry-tree:
+      size: 1448
+      sha256: dc39ed0207b8b22d2713054421dbd5452baa9704df75bedf17f04f97a29f3d9a
+  original:
+    hackage: hsass-0.8.0
+- completed:
+    hackage: hlibsass-0.1.8.1@sha256:7005d0f3fee66e776300117f6bf31583bf310f58df6d7f552c8811bd406abfc8,2564
+    pantry-tree:
+      size: 8441
+      sha256: c3c1fe56c35eed093772b9900d7038287b829d67960c6f96a82c9dc46b203db0
+  original:
+    hackage: hlibsass-0.1.8.1
+- completed:
+    hackage: tz-0.1.3.3@sha256:b9de0c1b10825460ff14a237209a8bf7747f47979601d35621276556bf63d2ca,5086
+    pantry-tree:
+      size: 1180
+      sha256: ae6af45f3dba5a478ea9cc77c718f955fcc5c96f2dc0f4ede34c4a15a3e85ac1
+  original:
+    hackage: tz-0.1.3.3
 - completed:
     hackage: uuid-crypto-1.4.0.0@sha256:9e2f271e61467d9ea03e78cddad75a97075d8f5108c36a28d59c65abb3efd290,1325
     pantry-tree:
@@ -68,17 +124,17 @@ packages:
   original:
     hackage: uuid-crypto-1.4.0.0
 - completed:
-    hackage: filepath-crypto-0.1.0.0@sha256:d5d33a2c9d044d025bbbfd4e5fab61f77228604b3cb7ea46e9164f8c8bcc9fb4,1593
+    hackage: filepath-crypto-0.1.0.0@sha256:e02bc15858cf06edf9788a38b5b58d45e82c7f5589785a178a903d792af04125,1593
     pantry-tree:
       size: 623
-      sha256: 3663e7b1ba2d80c51967a97fb67047bb3d3b5acdaa2b82f4036c4117b3238a49
+      sha256: bce236365ebdc6e5c46f740876a6fb5ad688e8ee3b305933822ab027e5b5fd86
   original:
     hackage: filepath-crypto-0.1.0.0
 - completed:
-    hackage: cryptoids-0.5.1.0@sha256:986f0f0e966a83505013f225a4b7805f03c656822704d2a516bf68caf2a9ee04,1570
+    hackage: cryptoids-0.5.1.0@sha256:729cd89059c6b6a50e07b2e279f6d95ee9432caeedc7e2f38f71e59c422957bc,1570
     pantry-tree:
       size: 513
-      sha256: 4348c28a66cd53602df6c04961f2b980756273f17a1dcefa8c61b6857f7564be
+      sha256: 563e8d2b616ec3e0e7984d6b069095b6c3959065c0bb047fc8dd5809711a3e6b
   original:
     hackage: cryptoids-0.5.1.0
 - completed:
@@ -117,61 +173,12 @@ packages:
   original:
     hackage: pkcs7-1.0.0.1
 - completed:
-    hackage: systemd-1.2.0@sha256:94995d4f1268aa0049d1793b21adb1522b6041e270cea4095c43eb589cc7ce53,1389
+    hackage: systemd-2.2.0@sha256:a41399ad921e3c90bb04219a66821631c17c94326961f9b6c71542abb042375f,1477
     pantry-tree:
-      size: 386
-      sha256: 16d20860c99050194570c4760337a9d9c156580dbe0ae707f4039f6da1474a93
+      size: 520
+      sha256: 188d4e07a62653b24091dc25c0222deb7a95037630d17a13327d269391050b7d
   original:
-    hackage: systemd-1.2.0
-- completed:
-    hackage: directory-1.3.4.0@sha256:500019f04494324d1df16cf83eefeb3f809b2b20b32a32ccd755ee0439c18bfd,2829
-    pantry-tree:
-      size: 3365
-      sha256: 00c09e0c014d29ebfb921b64c1459e61a0ad6f10e70128d795246a47c06394b0
-  original:
-    hackage: directory-1.3.4.0
-- completed:
-    hackage: HaXml-1.25.5@sha256:4f8534cda290b3d0a76b4ca5c4b9aa20902dcf029ddd50998d07c5dd608ad6f6,4420
-    pantry-tree:
-      size: 4076
-      sha256: 9682020b148433c41f5efee327b66708875015df8d4b3d48f875ac21f8222e1b
-  original:
-    hackage: HaXml-1.25.5
-- completed:
-    hackage: persistent-2.10.4@sha256:16c4c0823dd5e16bac4d607895ab0f4febd0626c020e5755ed1a52bf04068148,4738
-    pantry-tree:
-      size: 2094
-      sha256: b40d1783b539ddbbceaa827bf286d0b3bfcf76ca19e604c9d510b2a64008714e
-  original:
-    hackage: persistent-2.10.4
-- completed:
-    hackage: persistent-postgresql-2.10.1@sha256:ea53a0f1f4223b4884b5e19511325367879560d2432a02a976aa4da57c5fb760,2871
-    pantry-tree:
-      size: 740
-      sha256: 3cdbc757b1cebb65542fb919369be238b3f120adc45f023084a8b64c214d9675
-  original:
-    hackage: persistent-postgresql-2.10.1
-- completed:
-    hackage: persistent-template-2.7.3@sha256:ac3e5e8c48e968b927bbf4e97162c52e7e417d69b05efeb1c581d7c682e043d2,2703
-    pantry-tree:
-      size: 560
-      sha256: fdfb2a721eb9c9831d7381d36bc52de0808a008ed3d553b6490080f337249684
-  original:
-    hackage: persistent-template-2.7.3
-- completed:
-    hackage: esqueleto-3.2.3@sha256:5e1e0a8600e2744127ef4bb5956fa84ae6bc1fc337c7b8726fabb7ca53e2d9b3,5466
-    pantry-tree:
-      size: 1461
-      sha256: f6215274a43addd339f8bc89f1ca0e8fdfb08180b13d779ae8f7e360acc4c473
-  original:
-    hackage: esqueleto-3.2.3
-- completed:
-    hackage: HaskellNet-SSL-0.3.4.1@sha256:3ca14dd69460a380cf69aed40654fb10c4c03e344632b6a9986568c87feda157,1843
-    pantry-tree:
-      size: 577
-      sha256: 33fbfd0d8bbaa689f0169d442861dafcdcd4fe795a4b42aa0bedbfa41aa65b23
-  original:
-    hackage: HaskellNet-SSL-0.3.4.1
+    hackage: systemd-2.2.0
 - completed:
     hackage: sandi-0.5@sha256:b278d072ca717706ea38f9bd646e023f7f2576a778fb43565b434f93638849aa,3010
     pantry-tree:
@@ -187,89 +194,12 @@ packages:
   original:
     hackage: storable-endian-0.2.6
 - completed:
-    hackage: universe-1.2@sha256:23e7486709c06f6b0e048a505f0bd8b82a9c5d0937c8a13ca215ff20adde0a77,1448
-    pantry-tree:
-      size: 292
-      sha256: 15f7f0675229769705c128a397c06c41eb86909ff34ddb4c4c0f7d77becbe71b
-  original:
-    hackage: universe-1.2
-- completed:
-    hackage: universe-base-1.1.1@sha256:732e72a3597f834a01710c055d540cbc4174a8465015c1cdaaa542e9aeeadbd0,2476
-    pantry-tree:
-      size: 465
-      sha256: 165dbd1fa5eb81244b1ae2f9f527ebf4cc6d430911649347b33a92b97b377267
-  original:
-    hackage: universe-base-1.1.1
-- completed:
-    hackage: universe-reverse-instances-1.1@sha256:9d46e98a81556a54c5be3346bc6e087cbd0036255eeb34cb28b3e59ab48646d3,1283
-    pantry-tree:
-      size: 549
-      sha256: 042fe63484542fa40a6071fad7c2930a85c569dce32280d5bc4b17e243b7cda4
-  original:
-    hackage: universe-reverse-instances-1.1
-- completed:
-    hackage: unliftio-pool-0.2.1.0@sha256:4de658feb1b10051c5af024c20cd7baa369c777716c54a7b3e2888a73286aecf,922
-    pantry-tree:
-      size: 217
-      sha256: ddec03547e1feda7e861b49b2d1f2e188d41dc7bd04ae3d831f57d0813eb09a5
-  original:
-    hackage: unliftio-pool-0.2.1.0
-- completed:
-    hackage: universe-instances-extended-1.1.1@sha256:6dfe9a7bbeb890a556c7f05ce3447ecd9e268e25a165ee233ad82ce76f91f327,1589
-    pantry-tree:
-      size: 251
-      sha256: 35972f6a95c04c018a0a634cc07f3c10c625e25e99e2f2b8090cebcf5f0292bd
-  original:
-    hackage: universe-instances-extended-1.1.1
-- completed:
-    hackage: universe-some-1.2@sha256:e232f660c1cc130c8492e7267868ef6b08d47c54949cdf5c54b8500e6a280e78,2106
-    pantry-tree:
-      size: 299
-      sha256: 921349682b8aa7c0ea294cd63d9f8521691cc6247b2520e0ab107c81a4aa1df5
-  original:
-    hackage: universe-some-1.2
-- completed:
-    hackage: some-1.0.0.3@sha256:d4e7f7ef114b1ae01915fcff15a9b46a078d459e30791276a565f5c015128347,2020
-    pantry-tree:
-      size: 708
-      sha256: c2627940f4cf87189dc0cb967a048cabf3292a935efa292d5c1674af56e75a88
-  original:
-    hackage: some-1.0.0.3
-- completed:
-    hackage: network-bsd-2.8.1.0@sha256:47cb03786ff5371876582babc72cbd88efbcb96053f5bfbefbc024fa80380bb3,3742
-    pantry-tree:
-      size: 264
-      sha256: 90120543a56cc76ccd841dcbb73e4725115af9ca428120cde906c1b3ca2e7c88
-  original:
-    hackage: network-bsd-2.8.1.0
-- completed:
-    hackage: persistent-qq-2.9.1@sha256:1da17d907298ad5bc0798b0f759b59cb1bd4a4530681e0be54ad5366d7c5b1d5,1271
-    pantry-tree:
-      size: 333
-      sha256: e75333f07a956842811d48f267f596111b8aebd9ee5b50b9afe64c5efcb17c71
-  original:
-    hackage: persistent-qq-2.9.1
-- completed:
-    hackage: process-1.6.5.1@sha256:77a9afeb676357f67fe5cf1ad79aca0745fb6f7fb96b786d510af08f622643f6,2468
-    pantry-tree:
-      size: 1211
-      sha256: 19d944da6aa37944332e0726372288319852e5f72aa57dbc3516dc15e760a502
-  original:
-    hackage: process-1.6.5.1
-- completed:
-    hackage: generic-lens-1.2.0.0@sha256:b19e7970c93743a46bc3702331512a96d163de4356472f2d51a2945887aefe8c,6524
-    pantry-tree:
-      size: 4315
-      sha256: 9ed161eadfda5b1eb36cfcf077146f7b66db1da69f1041fc720aea287ec021b0
-  original:
-    hackage: generic-lens-1.2.0.0
-- completed:
-    hackage: prometheus-metrics-ghc-1.0.0@sha256:0f4ecbefa810bd847e66c498ab3387bf21e426525a7c9a94841973c582719ba3,1231
+    hackage: prometheus-metrics-ghc-1.0.1@sha256:d12cd520cbedff91bd193e0192056474723e953e69cdf817fb79494d110df390,1231
     pantry-tree:
       size: 293
-      sha256: 8a6d6ef3235ab980e867f64b712b5d38f1a84c3ac4920f5b4c3b3e63bcdf6ec9
+      sha256: b412f2835ee5791a7f4f634c416227b70bae50511666d9f68683e5e21b5c2821
   original:
-    hackage: prometheus-metrics-ghc-1.0.0
+    hackage: prometheus-metrics-ghc-1.0.1
 - completed:
     hackage: wai-middleware-prometheus-1.0.0@sha256:1625792914fb2139f005685be8ce519111451cfb854816e430fbf54af46238b4,1314
     pantry-tree:
@@ -277,13 +207,6 @@ packages:
       sha256: 6d64803c639ed4c7204ea6fab0536b97d3ee16cdecb9b4a883cd8e56d3c61402
   original:
     hackage: wai-middleware-prometheus-1.0.0
-- completed:
-    hackage: extended-reals-0.2.3.0@sha256:78a498d703fffcecfba8e66cfb3e64c4307b2c126a442f6d28cfdd997829f1bf,1563
-    pantry-tree:
-      size: 398
-      sha256: 29629bb0ac41c49671b7f792e540165ee091eb24ffd0eaff229a2f40cc03f3af
-  original:
-    hackage: extended-reals-0.2.3.0
 - completed:
     hackage: pandoc-2.9.2@sha256:fa04b214c79328a4519093a5e82fe961a21179539165b98773a6f8bfb66bc662,36181
     pantry-tree:
@@ -298,48 +221,6 @@ packages:
       sha256: ed2fc2dd826fbba67cb8018979be437b215735fab90dcc49ad30b296f7005eed
   original:
     hackage: doclayout-0.3
-- completed:
-    hackage: emojis-0.1@sha256:3cd86b552ad71c118a7822128c97054b6cf22bc4ff5b8f7e3eb0b356202aeecd,1907
-    pantry-tree:
-      size: 426
-      sha256: 0af0e5f0ba2af10a2eda8b96b41ff77d2229d90682c1220723a13b9582c4a41b
-  original:
-    hackage: emojis-0.1
-- completed:
-    hackage: hslua-module-system-0.2.1@sha256:7c498e51df885be5fd9abe9b762372ff4f125002824d8e11a7d5832154a7a1c3,2216
-    pantry-tree:
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-      sha256: 19a1e580174d2e02da4942887b2330804e8ceeed1ff4fd178a1bec4663e474ea
-  original:
-    hackage: hslua-module-system-0.2.1
-- completed:
-    hackage: ipynb-0.1@sha256:5b5240a9793781da557f82891d49cea63d71c8c5d3500fa3eac9fd702046b520,1926
-    pantry-tree:
-      size: 812
-      sha256: df171745ba4d6625eb71167a37237776cd10929994b05578b040592e2d5d5579
-  original:
-    hackage: ipynb-0.1
-- completed:
-    hackage: jira-wiki-markup-1.0.0@sha256:24484791e650c80c452348e2523decc9a410aa965f79c0734c1e257f93b25cd1,3576
-    pantry-tree:
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-      sha256: 60c39181a59a497be6c754e1cbf03461d9c4950bd4c523ca1efe1bd11e6f6b4f
-  original:
-    hackage: jira-wiki-markup-1.0.0
-- completed:
-    hackage: HsYAML-0.2.1.0@sha256:e4677daeba57f7a1e9a709a1f3022fe937336c91513e893166bd1f023f530d68,5311
-    pantry-tree:
-      size: 1340
-      sha256: 21f61bf9cad31674126b106071dd9b852e408796aeffc90eec1792f784107eff
-  original:
-    hackage: HsYAML-0.2.1.0
-- completed:
-    hackage: cmark-gfm-0.2.1@sha256:f49c10f6f1f8f41cb5d47e69ad6593dc45d2b28a083bbe22926d9f5bebf479b5,5191
-    pantry-tree:
-      size: 4555
-      sha256: 309d25e57e2c6d43834accc1f3a0f79150b9646f412957488d100e9cf7c37100
-  original:
-    hackage: cmark-gfm-0.2.1
 - completed:
     hackage: doctemplates-0.8.1@sha256:be34c3210d9ebbba1c10100e30d8c3ba3b6c34653ec2ed15f09e5d05055aa37d,3111
     pantry-tree:
@@ -347,44 +228,9 @@ packages:
       sha256: 9d4d8e7a85166ffd951b02f87be540607b55084c04730932346072329adf4913
   original:
     hackage: doctemplates-0.8.1
-- completed:
-    hackage: haddock-library-1.8.0@sha256:293544a80c3d817a021fec69c430e808914a9d86db0c6bd6e96a386607a66627,3850
-    pantry-tree:
-      size: 3397
-      sha256: 2fb23fd09565829807a0368011cd57ea13e9a79fa4c65a47810aaf9a528427c2
-  original:
-    hackage: haddock-library-1.8.0
-- completed:
-    hackage: pandoc-types-1.20@sha256:8393b1a73b8a6a1f3feaeb3a6592c176461082c3e4d897f1b316b1a58dd84c39,3999
-    pantry-tree:
-      size: 855
-      sha256: cdaa66d381a21406434e7a733c9b9291a3bc44b623e7a9f97ef335283770f3fa
-  original:
-    hackage: pandoc-types-1.20
-- completed:
-    hackage: skylighting-0.8.3.2@sha256:8b8573cd8820129a4c00675f52606f0f4c04c65d2e631e9e0e3d793cefdb534c,9730
-    pantry-tree:
-      size: 10380
-      sha256: cfe063d17444f6e12a8884cab7b2ec76afba9925be04155af605931793eac1f3
-  original:
-    hackage: skylighting-0.8.3.2
-- completed:
-    hackage: skylighting-core-0.8.3.2@sha256:1f7cb6c8bb9299a83c50ae1f4b00d3808e27e4401807c530c8c3df956ad26d23,8058
-    pantry-tree:
-      size: 13279
-      sha256: 1cc0d70bd3f066bf8382206721a1e3854b78fbd067ece3d76ddbfc1c4e73fd2b
-  original:
-    hackage: skylighting-core-0.8.3.2
-- completed:
-    hackage: texmath-0.12.0.1@sha256:f68e0d01b34f53552deb506ba0b53b5cbba1bc5d87cc0d3de1bb5662d00ca5db,6569
-    pantry-tree:
-      size: 274222
-      sha256: 7bcd4a5c93f645b84fc93285e4868d7a418c66408f115710a73ad5370df9edc2
-  original:
-    hackage: texmath-0.12.0.1
 snapshots:
 - completed:
-    size: 498180
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/13/21.yaml
-    sha256: eff2de19a6d4691ccbf6edc1fba858f1918683047dce0f09adede874bbd2a8f3
-  original: lts-13.21
+    size: 488576
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/15/0.yaml
+    sha256: e4b6a87b47ec1cf63a7f1a0884a3b276fce2b0d174a10e8753c4f618e7983568
+  original: lts-15.0
diff --git a/templates/course-participants.hamlet b/templates/course-participants.hamlet
index ff5847746..53460bdda 100644
--- a/templates/course-participants.hamlet
+++ b/templates/course-participants.hamlet
@@ -4,4 +4,4 @@ $#
 $# participantTable : widget table
 
 ^{participantTable}
-_{MsgCourseMembersCountOf (fromIntegral numParticipants) (courseCapacity course)}.
+_{MsgCourseMembersCountOf numParticipants (courseCapacity course)}.
diff --git a/test/Database.hs b/test/Database.hs
index c9a362047..976bf95b1 100755
--- a/test/Database.hs
+++ b/test/Database.hs
@@ -14,15 +14,10 @@ import Control.Monad.Logger
 
 import System.Console.GetOpt
 import System.Exit (exitWith, ExitCode(..))
-import System.IO (hPutStrLn, stderr)
-
-import System.FilePath ((</>))
+import System.IO (hPutStrLn)
 
 import qualified Data.ByteString as BS
 
-import Utils.Lens (review, view)
-import Control.Monad.Random.Class (MonadRandom(..))
-
 import qualified Data.Set as Set
 
 import Database.Persist.Sql.Raw.QQ
diff --git a/test/Handler/ProfileSpec.hs b/test/Handler/ProfileSpec.hs
index da8609703..280db8528 100644
--- a/test/Handler/ProfileSpec.hs
+++ b/test/Handler/ProfileSpec.hs
@@ -18,7 +18,7 @@ spec = withApp $ do
 
       assertHeader "Location" $ encodeUtf8 loginText
   
-      either (fail . unpack) (\_ -> return ()) =<< followRedirect
+      either (throwM . userError . unpack) (\_ -> return ()) =<< followRedirect
       statusIs 200
 
     it "asserts access to my-account for authenticated users" $ do
diff --git a/test/Handler/Utils/SubmissionSpec.hs b/test/Handler/Utils/SubmissionSpec.hs
index 3e05115dc..ff2c1c22b 100644
--- a/test/Handler/Utils/SubmissionSpec.hs
+++ b/test/Handler/Utils/SubmissionSpec.hs
@@ -1,3 +1,5 @@
+{-# OPTIONS_GHC -fno-warn-incomplete-uni-patterns #-}
+
 module Handler.Utils.SubmissionSpec where
 
 import qualified Yesod
diff --git a/test/Model/TypesSpec.hs b/test/Model/TypesSpec.hs
index 3feef17be..2ac485593 100644
--- a/test/Model/TypesSpec.hs
+++ b/test/Model/TypesSpec.hs
@@ -5,7 +5,6 @@ module Model.TypesSpec where
 import TestImport
 import Settings
 
-import Control.Lens (review, preview)
 import Data.Aeson (Value)
 import qualified Data.Aeson as Aeson
 import qualified Data.Aeson.Types as Aeson
@@ -23,8 +22,6 @@ import Text.Blaze.Renderer.Text
 
 import qualified Data.Set as Set
 
-import Time.Types (WeekDay(..))
-
 import qualified Net.IP as IP
 
 import Web.PathPieces
@@ -211,9 +208,6 @@ instance Arbitrary Html where
   arbitrary = (preEscapedToHtml :: String -> Html) . getPrintableString <$> arbitrary
   shrink = map preEscapedToHtml . shrink . renderMarkup
 
-instance Arbitrary WeekDay where
-  arbitrary = oneof $ map pure [minBound..maxBound]
-
 instance Arbitrary OccurrenceSchedule where
   arbitrary = genericArbitrary
   shrink = genericShrink
diff --git a/test/ModelSpec.hs b/test/ModelSpec.hs
index 654156578..67196ba0a 100644
--- a/test/ModelSpec.hs
+++ b/test/ModelSpec.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE UndecidableInstances #-}
+{-# OPTIONS_GHC -fno-warn-incomplete-uni-patterns #-}
 
 module ModelSpec where
 
diff --git a/test/TestImport.hs b/test/TestImport.hs
index 3c9b42427..123e67a24 100644
--- a/test/TestImport.hs
+++ b/test/TestImport.hs
@@ -37,7 +37,7 @@ import Test.QuickCheck.Classes.Binary as X
 import Test.QuickCheck.Classes.Csv as X
 import Data.Proxy as X
 import Data.UUID as X (UUID)
-import System.IO as X (hPrint, hPutStrLn, stderr)
+import System.IO as X (hPrint, hPutStrLn)
 import Jobs (handleJobs)
 import Numeric.Natural as X