Eliminate orphan rules and instances in the array package

[ghc-base.git] / Data / Foldable.hs

diff --git a/Data/Foldable.hs b/Data/Foldable.hs
index f2baddf..9d5502c 100644 (file)
--- a/Data/Foldable.hs
+++ b/Data/Foldable.hs
@@ -72,6 +72,12 @@ import Control.Arrow (ArrowZero(..)) -- work around nhc98 typechecker problem
 import GHC.Exts (build)
 #endif
 
+#if defined(__GLASGOW_HASKELL__)
+import GHC.Arr
+#elif defined(__HUGS__)
+import Hugs.Array
+#endif
+
 -- | Data structures that can be folded.
 --
 -- Minimal complete definition: 'foldMap' or 'foldr'.
@@ -147,6 +153,11 @@ instance Foldable [] where
         foldr1 = Prelude.foldr1
         foldl1 = Prelude.foldl1
 
+#ifndef __NHC__
+instance Ix i => Foldable (Array i) where
+    foldr f z = Prelude.foldr f z . elems
+#endif
+
 -- | Fold over the elements of a structure,
 -- associating to the right, but strictly.
 foldr' :: Foldable t => (a -> b -> b) -> b -> t a -> b