Fix some -Wcompat issues (MFP)

src/UI/Butcher/Monadic/Flag.hs

@@ -93,7 +93,7 @@ instance Semigroup (Flag p) where
 
 instance Monoid (Flag p) where
   mempty = Flag Nothing Nothing Visible
-  mappend = appendFlag
+  mappend = (<>)
 
 -- | Create a 'Flag' with just a help text.
 flagHelp :: PP.Doc -> Flag p

src/UI/Butcher/Monadic/Param.hs

@@ -57,8 +57,8 @@ data Param p = Param
 
 appendParam :: Param p -> Param p -> Param p
 appendParam (Param a1 b1 c1) (Param a2 b2 c2) = Param (a1 `f` a2)
-                                                      (b1 `mappend` b2)
+                                                      (b1 <> b2)
-                                                      (c1 `mappend` c2)
+                                                      (c1 <> c2)
  where
   f Nothing x = x
   f x       _ = x
@@ -68,7 +68,7 @@ instance Semigroup (Param p) where
 
 instance Monoid (Param p) where
   mempty = Param Nothing Nothing Nothing
-  mappend = appendParam
+  mappend = (<>)
 
 -- | Create a 'Param' with just a help text.
 paramHelpStr :: String -> Param p

srcinc/prelude.inc

@@ -337,8 +337,9 @@ import Debug.Trace                        ( trace
 import Foreign.ForeignPtr                 ( ForeignPtr
                                           )
 
-import Data.Monoid                        ( mconcat
+import Data.Monoid                        ( Monoid
-                                          , Monoid (..)
+                                          , mempty
+                                          , mconcat
                                           )
 
 import Data.Bifunctor                     ( bimap )