1 files changed, 15 insertions, 19 deletions

diff --git a/src/Data/Array/Nested/Internal.hs b/src/Data/Array/Nested/Internal.hs
index 19e6545..ab5f015 100644
--- a/src/Data/Array/Nested/Internal.hs
+++ b/src/Data/Array/Nested/Internal.hs
@@ -43,7 +43,7 @@ import Control.Monad.ST
 import qualified Data.Array.RankedS as S
 import Data.Bifunctor (first)
 import Data.Coerce (coerce, Coercible)
-import Data.Foldable (toList)
+import Data.Foldable as Foldable (toList)
 import Data.Functor.Const
 import Data.Kind
 import Data.List.NonEmpty (NonEmpty(..))
@@ -241,23 +241,19 @@ instance KnownNat n => IsList (ListR n i) where
       go SZ [] = ZR
       go (SS n) (i : is) = i ::: go n is
       go _ _ = error "IsList(ListR): Mismatched list length"
-  toList = go
-    where
-      go :: ListR n' i -> [i]
-      go ZR = []
-      go (i ::: is) = i : go is
+  toList = Foldable.toList
 
 -- | Untyped: length is checked at runtime.
 instance KnownNat n => IsList (IxR n i) where
   type Item (IxR n i) = i
   fromList = IxR . IsList.fromList
-  toList (IxR idx) = IsList.toList idx
+  toList = Foldable.toList
 
 -- | Untyped: length is checked at runtime.
 instance KnownNat n => IsList (ShR n i) where
   type Item (ShR n i) = i
   fromList = ShR . IsList.fromList
-  toList (ShR idx) = IsList.toList idx
+  toList = Foldable.toList
 
 
 type role ListS nominal representational
@@ -293,6 +289,10 @@ showListS f l = showString "[" . go "" l . showString "]"
     go _ ZS = id
     go prefix (x ::$ xs) = showString prefix . f x . go "," xs
 
+listSToList :: ListS sh (Const i) -> [i]
+listSToList ZS = []
+listSToList (Const i ::$ is) = i : listSToList is
+
 
 -- | An index into a shape-typed array.
 --
@@ -356,6 +356,10 @@ instance Show (ShS sh) where
 lengthShS :: ShS sh -> Int
 lengthShS (ShS l) = getSum (foldListS (\_ -> Sum 1) l)
 
+shSToList :: ShS sh -> [Int]
+shSToList ZSS = []
+shSToList (sn :$$ sh) = fromSNat' sn : shSToList sh
+
 
 -- | Untyped: length is checked at runtime.
 instance KnownShS sh => IsList (ListS sh (Const i)) where
@@ -368,17 +372,13 @@ instance KnownShS sh => IsList (ListS sh (Const i)) where
       go _ _ = error $ "IsList(ListS): Mismatched list length (type says "
                          ++ show (lengthShS (knownShS @sh)) ++ ", list has length "
                          ++ show (length topl) ++ ")"
-  toList = go
-    where
-      go :: ListS sh' (Const i) -> [i]
-      go ZS = []
-      go (Const i ::$ is) = i : go is
+  toList = listSToList
 
 -- | Very untyped: only length is checked (at runtime), index bounds are __not checked__.
 instance KnownShS sh => IsList (IxS sh i) where
   type Item (IxS sh i) = i
   fromList = IxS . IsList.fromList
-  toList (IxS idx) = IsList.toList idx
+  toList = Foldable.toList
 
 -- | Untyped: length and values are checked at runtime.
 instance KnownShS sh => IsList (ShS sh) where
@@ -394,11 +394,7 @@ instance KnownShS sh => IsList (ShS sh) where
       go _ _ = error $ "IsList(ShS): Mismatched list length (type says "
                          ++ show (lengthShS (knownShS @sh)) ++ ", list has length "
                          ++ show (length topl) ++ ")"
-  toList = go
-    where
-      go :: ShS sh' -> [Int]
-      go ZSS = []
-      go (sn :$$ sh) = fromSNat' sn : go sh
+  toList = shSToList
 
 
 -- | Wrapper type used as a tag to attach instances on. The instances on arrays