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-rw-r--r--users/glittershark/xanthous/src/Xanthous/Data.hs5
1 files changed, 4 insertions, 1 deletions
diff --git a/users/glittershark/xanthous/src/Xanthous/Data.hs b/users/glittershark/xanthous/src/Xanthous/Data.hs
index 3cb74bdca9..67173cc896 100644
--- a/users/glittershark/xanthous/src/Xanthous/Data.hs
+++ b/users/glittershark/xanthous/src/Xanthous/Data.hs
@@ -387,8 +387,11 @@ data Neighbors a = Neighbors
   , _bottomRight :: a
   }
   deriving stock (Show, Eq, Ord, Functor, Foldable, Traversable, Generic)
-  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving anyclass (NFData, CoArbitrary, Function, MonoFoldable)
   deriving Arbitrary via GenericArbitrary (Neighbors a)
+
+type instance Element (Neighbors a) = a
+
 makeFieldsNoPrefix ''Neighbors
 
 instance Applicative Neighbors where