Relax constraints on Semigroup and Monoid instances

Author: sjakobi

Data/HashMap/Internal.hs

@@ -311,7 +311,7 @@ instance Bifoldable HashMap where
 --
 -- >>> fromList [(1,'a'),(2,'b')] <> fromList [(2,'c'),(3,'d')]
 -- fromList [(1,'a'),(2,'b'),(3,'d')]
-instance Hashable k => Semigroup (HashMap k v) where
+instance Eq k => Semigroup (HashMap k v) where
   (<>) = union
   {-# INLINE (<>) #-}
   stimes = stimesIdempotentMonoid
@@ -327,7 +327,7 @@ instance Hashable k => Semigroup (HashMap k v) where
 --
 -- >>> mappend (fromList [(1,'a'),(2,'b')]) (fromList [(2,'c'),(3,'d')])
 -- fromList [(1,'a'),(2,'b'),(3,'d')]
-instance Hashable k => Monoid (HashMap k v) where
+instance Eq k => Monoid (HashMap k v) where
   mempty = empty
   {-# INLINE mempty #-}
   mappend = (<>)

Data/HashSet/Internal.hs

@@ -187,7 +187,7 @@ instance Foldable.Foldable HashSet where
 --
 -- >>> fromList [1,2] <> fromList [2,3]
 -- fromList [1,2,3]
-instance Hashable a => Semigroup (HashSet a) where
+instance Eq a => Semigroup (HashSet a) where
     (<>) = union
     {-# INLINE (<>) #-}
     stimes = stimesIdempotentMonoid
@@ -206,7 +206,7 @@ instance Hashable a => Semigroup (HashSet a) where
 --
 -- >>> mappend (fromList [1,2]) (fromList [2,3])
 -- fromList [1,2,3]
-instance Hashable a => Monoid (HashSet a) where
+instance Eq a => Monoid (HashSet a) where
     mempty = empty
     {-# INLINE mempty #-}
     mappend = (<>)