diff --git a/src/Prelude.hs b/src/Prelude.hs
index 50495eb1b9b0cce92ac16f39862e4da3868e7cef..1b8531350914e964efaf3e6fd026b3c942415e27 100644
--- a/src/Prelude.hs
+++ b/src/Prelude.hs
@@ -23,7 +23,7 @@ module Prelude
     traceShowId,
     traceM,
     traceShowM,
-    undefined
+    undefined,
   )
 where
 
@@ -86,4 +86,4 @@ traceShowM = Trace.traceShowM
 intercalate :: Monoid a => a -> [a] -> a
 intercalate _ [] = mempty
 intercalate _ [x] = x
-intercalate inter (x:xs) = x <> inter <> intercalate inter xs
+intercalate inter (x : xs) = x <> inter <> intercalate inter xs