add Arrow=>GArrowProd instance

[ghc-base.git] / GHC / HetMet / Arrow.hs

diff --git a/GHC/HetMet/Arrow.hs b/GHC/HetMet/Arrow.hs
index 08b75b3..b79943a 100644 (file)
--- a/GHC/HetMet/Arrow.hs
+++ b/GHC/HetMet/Arrow.hs
@@ -55,6 +55,10 @@ instance ArrowApply a => GArrowApply a (,) () a where
   ga_applyl    = ga_swap >>> app
   ga_applyr    = app
 
+instance Arrow a => GArrowProd a (,) () (,) () where
+  ga_prod_drop  = arr (\x -> ())
+  ga_prod_copy  = arr (\x -> (x,x))
+
 -- The uninhabited type
 data Void