diff --git a/.travis.yml b/.travis.yml
index f76d1b6..0e441c3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,5 +15,5 @@ matrix:
     - NIXPKGS=https://github.com/NixOS/nixpkgs-channels/archive/nixos-19.03.tar.gz
 
 script:
-  # - nix run nixpkgs.haskellPackages.hlint -c hlint src
+  - nix run nixpkgs.haskellPackages.hlint -c hlint src
   - nix build -I nixpkgs=$NIXPKGS -f ./release.nix xmonad-masser
diff --git a/src/XMonad/Config/MasseR.hs b/src/XMonad/Config/MasseR.hs
index 43e906a..e8c1342 100644
--- a/src/XMonad/Config/MasseR.hs
+++ b/src/XMonad/Config/MasseR.hs
@@ -184,7 +184,7 @@ myKeys extraConfig conf =
                         , ("M-n", scratchSubmaps conf)
                         , ("M-s", searchSubmaps conf)
                         , ("M-p", addName "Retrieve password" $ passPrompt def)
-                        , ("M-S-e", addName "Open with app" xdg_open)
+                        , ("M-S-e", addName "Open with app" xdgOpen)
                         , ("M-e", addName "Run app" $ runOrRaisePrompt def)] ^++^
     subKeys "Windows" [ ("M-j", addName "Go down" $ windowGo D False)
                       , ("M-k", addName "Go up" $ windowGo U False)
diff --git a/src/XMonad/CustomPrompt.hs b/src/XMonad/CustomPrompt.hs
index f3859b6..b801183 100644
--- a/src/XMonad/CustomPrompt.hs
+++ b/src/XMonad/CustomPrompt.hs
@@ -1,4 +1,4 @@
-module XMonad.CustomPrompt (xdg_open, browser) where
+module XMonad.CustomPrompt (xdgOpen, browser) where
 
 import qualified XMonad.Prompt.AppLauncher as AL
 import XMonad.Prompt
@@ -7,8 +7,8 @@ import XMonad (X)
 launchApp ::  AL.Application -> X ()
 launchApp = AL.launchApp def
 
-xdg_open :: X ()
-xdg_open = launchApp "xdg-open"
+xdgOpen :: X ()
+xdgOpen = launchApp "xdg-open"
 
 browser :: X ()
 browser = launchApp "qutebrowser"
diff --git a/src/XMonad/Password.hs b/src/XMonad/Password.hs
index f009161..7de907a 100644
--- a/src/XMonad/Password.hs
+++ b/src/XMonad/Password.hs
@@ -10,7 +10,7 @@ import           XMonad.Core
 import           XMonad.Prompt
 import           XMonad.Util.Run       (runProcessWithInput)
 
-data Pass = Pass { passLabel :: String }
+newtype Pass = Pass { passLabel :: String }
 
 -- Rosetta code levenshtein
 levenshtein :: String -> String -> Int
@@ -37,7 +37,7 @@ mkPassPrompt label f conf = do
   -- I'm just sorting here, but could use some kind of fuzzy matching instead, but it requires a bit more effort
   passwords <- sort <$> liftIO getPasswords
   -- Other change, use infixof instead of prefixof
-  mkXPrompt (Pass label) conf (\input -> pure (sortBy (compare `on` (levenshtein input)) . filter (consumes input) $ passwords)) f
+  mkXPrompt (Pass label) conf (\input -> pure (sortBy (compare `on` levenshtein input) . filter (consumes input) $ passwords)) f
   where
     consumes [] _ = True -- everything consumed
     consumes (_:_) [] = False -- all not consumed
diff --git a/src/XMonad/TopicUtils.hs b/src/XMonad/TopicUtils.hs
index 26c9624..63e536e 100644
--- a/src/XMonad/TopicUtils.hs
+++ b/src/XMonad/TopicUtils.hs
@@ -1,7 +1,8 @@
+{-# LANGUAGE TupleSections #-}
 module XMonad.TopicUtils where
 
 import Data.Maybe (fromMaybe, listToMaybe, mapMaybe)
-import Data.List (isPrefixOf, sort, nub)
+import Data.List (isPrefixOf, nub, sortOn)
 import XMonad.Actions.TopicSpace
 import XMonad
 import qualified Data.Map as M
@@ -11,6 +12,7 @@ import qualified XMonad.StackSet as W
 import XMonad.Util.Dmenu (dmenu)
 import XMonad.Actions.DynamicWorkspaces
 import XMonad.Util.NamedWindows (getName)
+import Data.Ord
 
 
 realTopicDir :: M.Map String FilePath -> X String
@@ -58,7 +60,7 @@ gridselectCurrentWindows :: GSConfig Window -> X (Maybe Window)
 gridselectCurrentWindows gsconf = windowMap >>= gridselect gsconf
     where
         getName' = fmap show . getName
-        kvPair w = flip (,) w `fmap` getName' w
+        kvPair w = (, w) <$> getName' w
         windowMap = do
             ws <- gets (nub . W.integrate' . W.stack . W.workspace . W.current . windowset)
             mapM kvPair ws
@@ -78,11 +80,11 @@ currentTopicAction' tg = do
 copyTopic :: X ()
 copyTopic = do
   currentTopic <- realTopic
-  lastN <- gets (listToMaybe . reverse . sort . mapMaybe (subset currentTopic . W.tag) . W.workspaces . windowset)
-  addWorkspace (currentTopic ++ ":" ++ (show $ maybe 2 (+1) lastN))
+  lastN <- gets (listToMaybe . sortOn Down . mapMaybe (subset currentTopic . W.tag) . W.workspaces . windowset)
+  addWorkspace (currentTopic ++ ":" ++ show (maybe 2 (+1) lastN))
   where
     subset :: String -> String -> Maybe Int
-    subset topic other = if topic `isPrefixOf` other then (readM $ tail' $ snd $ break (== ':') other) else Nothing
+    subset topic other = if topic `isPrefixOf` other then readM $ tail' $ dropWhile (/= ':') other else Nothing
     readM a = case reads a of
                [(x,_)] -> Just x
                _ -> Nothing