1 files changed, 2 insertions, 0 deletions
diff --git a/src/Data/Array/Nested/Convert.hs b/src/Data/Array/Nested/Convert.hs
index cea2489..d07bab9 100644
--- a/src/Data/Array/Nested/Convert.hs
+++ b/src/Data/Array/Nested/Convert.hs
@@ -3,6 +3,7 @@
 {-# LANGUAGE PolyKinds #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE TypeAbstractions #-}
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE TypeOperators #-}
@@ -150,6 +151,7 @@ data Castable a b where
             => Castable (Mixed sh a, Mixed sh b) (Mixed sh (a, b))
   CastUnzip :: (Elt a, Elt b)
             => Castable (Mixed sh (a, b)) (Mixed sh a, Mixed sh b)
+deriving instance Show (Castable a b)
 
 instance Category Castable where
   id = CastId