diff --git a/copilot-libraries.cabal b/copilot-libraries.cabal
--- a/copilot-libraries.cabal
+++ b/copilot-libraries.cabal
@@ -1,6 +1,6 @@
 cabal-version:       >=1.10
 name:                copilot-libraries
-version:             2.2.0
+version:             2.2.1
 synopsis:            Libraries for the Copilot language.
 description:
   Libraries for the Copilot language.
@@ -12,13 +12,13 @@
   <https://github.com/leepike/copilot-discussion>.
   .
   Examples are available at
-  <https://github.com/leepike/Copilot/tree/master/Examples>.
+  <https://github.com/Copilot-Language/Copilot/tree/master/Examples>.
 
 license:             BSD3
 license-file:        LICENSE
 author:              Lee Pike, Robin Morisset, Alwyn Goodloe, Sebastian Niller,
                      Nis Nordby Wegmann
-homepage:            https://github.com/leepike/copilot-libraries
+homepage:            https://github.com/Copilot-Language/copilot-libraries
 maintainer:          leepike@gmail.com
 stability:           Experimental
 category:            Language, Embedded
@@ -26,7 +26,7 @@
 
 source-repository head
     type:       git
-    location:   git://github.com/leepike/copilot-libraries.git
+    location:   git://github.com/Copilot-Language/copilot-libraries.git
 
 library
   default-language: Haskell2010
@@ -37,7 +37,7 @@
     array,
     base >= 4.0 && <= 5.0,
     containers,
-    copilot-language == 2.2.0,
+    copilot-language == 2.2.1,
     parsec >= 2.0,
     mtl >= 2.0
 
diff --git a/src/Copilot/Library/Utils.hs b/src/Copilot/Library/Utils.hs
--- a/src/Copilot/Library/Utils.hs
+++ b/src/Copilot/Library/Utils.hs
@@ -1,4 +1,4 @@
--- | 
+-- |
 -- Module: Utils
 -- Description: Utility bounded-list functions (e.g., folds, scans, etc.)
 -- Copyright: (c) 2011 National Institute of Aerospace / Galois, Inc.
@@ -13,7 +13,7 @@
          -- ** Scans
          nscanl, nscanr, nscanl1, nscanr1,
          -- ** Indexing
-         case', (!!)) 
+         case', (!!))
 where
 
 import Copilot.Language
@@ -83,11 +83,9 @@
                    P.++ "greater by one than the length of predicates list"
   in case'' predicates alternatives
 
-
 -- | Index.  WARNING: Very expensive!  Consider using this only for very short
 -- lists.
-(!!) :: ( Typed a, Integral a )
-        => [ Stream a ] -> Stream a -> Stream a
+(!!) :: (Typed a, Eq b, Num b, Typed b) => [Stream a] -> Stream b -> Stream a
 ls !! n = let indices      = map
                              ( constant . fromIntegral )
                              [ 0 .. P.length ls - 1 ]
@@ -96,10 +94,10 @@
                 ( i : is )
                 ( x : xs ) = mux ( i == n ) x ( select is xs )
                              -- should not happen
-              select _ []  = badUsage ("in (!!) defined in Utils.hs " P.++ 
+              select _ []  = badUsage ("in (!!) defined in Utils.hs " P.++
                                "in copilot-libraries")
           in if null ls then
-               badUsage ("in (!!) defined in Utils.hs " P.++ 
+               badUsage ("in (!!) defined in Utils.hs " P.++
                             "indexing the empty list with !! is not defined")
              else
                select indices ls