Proposal for our own HLint rules

HLint.hs

@@ -3,4 +3,10 @@ import "hint" HLint.Builtin.All
 
 ignore "Eta reduce"
 
-error = x `mappend` y `mappend` z  ==> mconcat [x, y, z]
+error   "use mconcat"                            = x `mappend` y `mappend` z   ==> mconcat [x, y, z]
+warning "use concat"                             = x ++ y ++ z   ==> concat [x, y, z]
+warning "use fromMaybe"                          = \case {Nothing -> a; Just b -> b} ==> fromMaybe a
+error   "putEditorDynA works on any MonadEditor" = withEditor $ putEditorDynA a ==> putEditorDynA a
+error   "getEditorDynA works on any MonadEditor" = withEditor $ getEditorDynA a ==> getEditorDynA a
+error   "Why not use <$>?"                       = a          >>= return . b             ==> b <$> a
+error   "Why not use <$>?"                       = return . b =<< a                      ==> b <$> a