src/Data/Finitary.hs

@@ -205,6 +205,8 @@ class (Eq a, KnownNat (Cardinality a)) => Finitary (a :: Type) where
 
   type Cardinality a = GCardinality (Rep a)
 
+  {-# MINIMAL fromFinite, toFinite #-}
+
   -- | Converts an index into its corresponding inhabitant.
   fromFinite :: Finite (Cardinality a) -> a
   default fromFinite :: (Generic a, GFinitary (Rep a), Cardinality a ~ GCardinality (Rep a)) => Finite (Cardinality a) -> a