diff --git a/src/Mulkup/Flags.hs b/src/Mulkup/Flags.hs
index c5aa758..fd95b83 100644
--- a/src/Mulkup/Flags.hs
+++ b/src/Mulkup/Flags.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
 
 module Mulkup.Flags (Flags (..), flagParser) where