diff --git a/bench/bench.hs b/bench/bench.hs
--- a/bench/bench.hs
+++ b/bench/bench.hs
@@ -15,8 +15,6 @@
 import qualified Data.Set as S
 import qualified Data.DList as D
 
-import Control.DeepSeq
-
 import Control.Monad.RWS
 
 testActions :: (Monoid w, Monad m, MonadRWS () w Int m) => (Int -> m ()) -> m ()
@@ -36,9 +34,6 @@
               , ("RWS.Lazy"  , RWSL.runRWS (testActions (tell . cnv)) ())
               , ("RWS.Strict", RWSS.runRWS (testActions (tell . cnv)) ())
               ]
-
-instance NFData a => NFData (D.DList a) where
-    rnf d = rnf $ D.toList d
 
 main :: IO ()
 main = defaultMain $ mkBench "Seq" Seq.singleton
diff --git a/stateWriter.cabal b/stateWriter.cabal
--- a/stateWriter.cabal
+++ b/stateWriter.cabal
@@ -1,18 +1,18 @@
--- Initial stateWriter.cabal generated by cabal init.  For further 
+-- Initial stateWriter.cabal generated by cabal init.  For further
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                stateWriter
-version:             0.2.6
+version:             0.2.7
 synopsis:            A faster variant of the RWS monad transformers.
 description:         This is a version of the RWS monad transformers that should be much faster than what's found in transformers. The writer in the strict version does not leak memory.
 license:             BSD3
 license-file:        LICENSE
 author:              Simon Marechal
 maintainer:          bartavelle@gmail.com
--- copyright:           
+-- copyright:
 category:            Control
 build-type:          Simple
--- extra-source-files:  
+-- extra-source-files:
 cabal-version:       >=1.10
 
 source-repository head
@@ -23,10 +23,10 @@
   exposed-modules:     Control.Monad.Trans.RSS.Lazy, Control.Monad.Trans.RSS.Strict, Control.Monad.RSS.Lazy, Control.Monad.RSS.Strict, Control.Monad.RSS, Control.Monad.Trans.RSS
   ghc-options:         -Wall
   ghc-prof-options:    -caf-all -auto-all
-  -- other-modules:       
+  -- other-modules:
   other-extensions:    FlexibleInstances, MultiParamTypeClasses
   build-depends:       base >=4.6 && < 4.9, transformers >=0.3 && <0.5, mtl >=2.1 && <2.3
-  -- hs-source-dirs:      
+  -- hs-source-dirs:
   default-language:    Haskell2010
 
 test-suite spaceleak
@@ -49,7 +49,7 @@
     hs-source-dirs: bench
     type:           exitcode-stdio-1.0
     ghc-options:    -Wall -rtsopts -O2 -fllvm
-    build-depends:  stateWriter,base,criterion,containers,mtl,transformers,lens,vector,dlist,deepseq
+    build-depends:  stateWriter,base,criterion,containers,mtl,transformers,lens,vector,dlist >= 0.7,deepseq
     main-is:        bench.hs
     default-language:    Haskell2010