diff --git a/numhask-array.cabal b/numhask-array.cabal
--- a/numhask-array.cabal
+++ b/numhask-array.cabal
@@ -1,5 +1,5 @@
 name: numhask-array
-version: 0.3
+version: 0.3.0.1
 synopsis:
   n-dimensional arrays
 description:
diff --git a/src/NumHask/Array.hs b/src/NumHask/Array.hs
--- a/src/NumHask/Array.hs
+++ b/src/NumHask/Array.hs
@@ -54,8 +54,8 @@
     Array { _getContainer :: c t}
     deriving (Functor, Foldable)
 
-instance NFData (Array c ds t) where
-  rnf a = seq a ()
+instance NFData (Array c (ds :: [Nat]) t) where
+  rnf (Array c) = seq c ()
 
 {-
 -- | instance of array where some of the dimensions are known at compile time