anchor.diff:    ghc703Prefs =
       self : self.haskellPlatformArgs_2011_2_0_1 self // {
         haskellPlatform = self.haskellPlatform_2011_2_0_1;
  -      repaExamples = null;      # don't pick this version of 'repa-examples' during nix-env -u
         cabalInstall_0_14_0 = self.cabalInstall_0_14_0.override { Cabal = self.Cabal_1_14_0; zlib = self.zlib_0_5_3_3; };
         monadPar = self.monadPar_0_1_0_3;
         jailbreakCabal = self.jailbreakCabal.override { Cabal = self.Cabal_1_14_0; };
  
positive.code:   ghc701Prefs =
      self : self.haskellPlatformArgs_2011_2_0_0 self // {
        haskellPlatform = self.haskellPlatform_2011_2_0_0;
        repaExamples = null;      # don't pick this version of 'repa-examples' during nix-env -u
        cabalInstall_0_14_0 = self.cabalInstall_0_14_0.override { Cabal = self.Cabal_1_14_0; zlib = self.zlib_0_5_3_3; };
        monadPar = self.monadPar_0_1_0_3;
        jailbreakCabal = self.jailbreakCabal.override { Cabal = self.Cabal_1_14_0; };
  
negative.code:       mtl1 = self.mtl_1_1_0_2;
        extensibleExceptions = self.extensibleExceptions_0_1_1_0;
        text = self.text_0_11_0_6;
        cabalInstall_0_14_0 = self.cabalInstall_0_14_0.override { Cabal = self.Cabal_1_14_0; zlib = self.zlib_0_5_3_3; };
        deepseq = self.deepseq_1_1_0_2;
        monadPar = self.monadPar_0_1_0_3;
  