diff --git a/Data/Repa/Chain/Base.hs b/Data/Repa/Chain/Base.hs
--- a/Data/Repa/Chain/Base.hs
+++ b/Data/Repa/Chain/Base.hs
@@ -48,9 +48,7 @@
 
 
 -- | Resume a chain computation from a previous state.
-resumeChain  
-        :: Monad m 
-        => s -> Chain m s a -> Chain m s a
+resumeChain :: s -> Chain m s a -> Chain m s a
 resumeChain s' (Chain sz _s step)
  = Chain sz s' step
 {-# INLINE_STREAM resumeChain #-}
diff --git a/Data/Repa/Vector/Generic.hs b/Data/Repa/Vector/Generic.hs
--- a/Data/Repa/Vector/Generic.hs
+++ b/Data/Repa/Vector/Generic.hs
@@ -271,7 +271,6 @@
 -------------------------------------------------------------------------------
 -- | Merge two pre-sorted key-value streams.
 merge   :: ( Ord k
-           , GV.Vector v k
            , GV.Vector v (k, a)
            , GV.Vector v (k, b)
            , GV.Vector v (k, c))
@@ -294,7 +293,6 @@
 --   return `Just`.
 mergeMaybe 
         :: ( Ord k
-           , GV.Vector v k
            , GV.Vector v (k, a)
            , GV.Vector v (k, b)
            , GV.Vector v (k, c))
diff --git a/repa-stream.cabal b/repa-stream.cabal
--- a/repa-stream.cabal
+++ b/repa-stream.cabal
@@ -1,5 +1,5 @@
 Name:           repa-stream
-Version:        4.2.2.1
+Version:        4.2.3.1
 License:        BSD3
 License-file:   LICENSE
 Author:         The Repa Development Team
@@ -19,11 +19,11 @@
 
 Library
   build-Depends: 
-        base            == 4.8.*,
+        base            == 4.9.*,
         vector          == 0.10.*,
         primitive       == 0.6.*,
         mtl             == 2.2.*,
-        repa-scalar     == 4.2.2.*
+        repa-scalar     == 4.2.3.*
 
   exposed-modules:
         Data.Repa.Chain