ghc 7.8.4 Foldable compat

Author: shekeru

Data/HashMap/Base.hs

@@ -201,11 +201,12 @@ instance Foldable.Foldable (HashMap k) where
     {-# INLINE foldr #-}
     foldl' = Data.HashMap.Base.foldl'
     {-# INLINE foldl' #-}
+#if MIN_VERSION_base(4,8,0)
     null = Data.HashMap.Base.null
     {-# INLINE null #-}
     length = Data.HashMap.Base.size
     {-# INLINE length #-}
-
+#endif
 
 #if __GLASGOW_HASKELL__ >= 711
 instance (Eq k, Hashable k) => Semigroup (HashMap k v) where

Data/HashSet/Base.hs

@@ -142,12 +142,14 @@ instance Foldable.Foldable HashSet where
     {-# INLINE foldr #-}
     foldl' = Data.HashSet.Base.foldl'
     {-# INLINE foldl' #-}
+#if MIN_VERSION_base(4,8,0)
     toList = Data.HashSet.Base.toList
     {-# INLINE toList #-}
     null = Data.HashSet.Base.null
     {-# INLINE null #-}
     length = Data.HashSet.Base.size
     {-# INLINE length #-}
+#endif
 
 #if __GLASGOW_HASKELL__ >= 711
 instance (Hashable a, Eq a) => Semigroup (HashSet a) where