Add GNFData instances for :*: and :+:

Author: phadej

src/Data/GADT/DeepSeq.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE CPP         #-}
 {-# LANGUAGE GADTs       #-}
+{-# LANGUAGE TypeOperators       #-}
 #if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds   #-}
 #endif
@@ -19,6 +20,10 @@ import Data.Functor.Product (Product (..))
 import Data.Functor.Sum     (Sum (..))
 import Data.Type.Equality   ((:~:) (..))
 
+#if MIN_VERSION_base(4,6,0)
+import GHC.Generics         ((:+:) (..), (:*:) (..))
+#endif
+
 #if MIN_VERSION_base(4,9,0)
 #if MIN_VERSION_base(4,10,0)
 import  Data.Type.Equality ((:~~:) (..))
@@ -49,6 +54,15 @@ instance (GNFData a, GNFData b) => GNFData (Sum a b) where
     grnf (InL x) = grnf x
     grnf (InR y) = grnf y
 
+#if MIN_VERSION_base(4,6,0)
+instance (GNFData a, GNFData b) => GNFData (a :*: b) where
+    grnf (a :*: b) = grnf a `seq` grnf b
+
+instance (GNFData a, GNFData b) => GNFData (a :+: b) where
+    grnf (L1 x) = grnf x
+    grnf (R1 y) = grnf y
+#endif
+
 -- | @since 1.0.3
 instance GNFData ((:~:) a) where
     grnf Refl = ()