anchor.diff:        ghc-parser        = self.callCabal2nix "ghc-parser" ghc-parser-src {};
         ipython-kernel    = self.callCabal2nix "ipython-kernel" ipython-kernel-src {};
   
  -      here              = nixpkgs.haskell.lib.doJailbreak super.here;
         hlint             = super.hlint.overrideScope (_self: _super: { haskell-src-exts = self.haskell-src-exts; });
         hourglass         = super.hourglass.overrideAttrs (oldAttrs: {
           src = nixpkgs.fetchFromGitHub {
  
positive.code:           sha256 = "1rxai65xk6pcj3jahh62x543r1lgmzd4xjaj538nsb1aww0jyk77";
          };
        });
        http-types        = nixpkgs.haskell.lib.dontCheck super.http-types;
        tls               = nixpkgs.haskell.lib.overrideCabal super.tls (_drv: {
          postPatch = let
            original = ''
              instance Monoid Credentials where
                  mempty = Credentials []
                  mappend (Credentials l1) (Credentials l2) = Credentials (l1 ++ l2)
            '';
            replacement = ''
              instance Semigroup Credentials where
                  (<>) (Credentials l1) (Credentials l2) = Credentials (l1 ++ l2)
  
              instance Monoid Credentials where
                  mempty  = Credentials []
            '';
          in ''
            substituteInPlace ./Network/TLS/Credentials.hs --replace \
              '${original}' '${replacement}'
          '';
        });
        x509              = nixpkgs.haskell.lib.overrideCabal super.x509 (_drv: {
          postPatch = let
            original = ''
              instance Monoid DistinguishedName where
                  mempty  = DistinguishedName []
                  mappend (DistinguishedName l1) (DistinguishedName l2) = DistinguishedName (l1++l2)
            '';
            replacement = ''
              instance Semigroup DistinguishedName where
                  (<>) (DistinguishedName l1) (DistinguishedName l2) = DistinguishedName (l1++l2)
  
              instance Monoid DistinguishedName where
                  mempty  = DistinguishedName []
            '';
          in ''
            substituteInPlace ./Data/X509/DistinguishedName.hs --replace \
              '${original}' '${replacement}'
          '';
        });
        x509-store        = nixpkgs.haskell.lib.overrideCabal super.x509-store (_drv: {
          postPatch = let
            original = ''
              instance Monoid CertificateStore where
                  mempty  = CertificateStore M.empty
                  mappend s1@(CertificateStore _)   s2@(CertificateStore _) = CertificateStores [s1,s2]
                  mappend    (CertificateStores l)  s2@(CertificateStore _) = CertificateStores (l ++ [s2])
                  mappend s1@(CertificateStore _)   (CertificateStores l)   = CertificateStores ([s1] ++ l)
                  mappend    (CertificateStores l1) (CertificateStores l2)  = CertificateStores (l1 ++ l2)
            '';
            replacement = ''
              instance Semigroup CertificateStore where
                  (<>) s1@(CertificateStore _)   s2@(CertificateStore _) = CertificateStores [s1,s2]
                  (<>)    (CertificateStores l)  s2@(CertificateStore _) = CertificateStores (l ++ [s2])
                  (<>) s1@(CertificateStore _)   (CertificateStores l)   = CertificateStores ([s1] ++ l)
                  (<>)    (CertificateStores l1) (CertificateStores l2)  = CertificateStores (l1 ++ l2)
  
              instance Monoid CertificateStore where
                  mempty  = CertificateStore M.empty
            '';
          in ''
            substituteInPlace ./Data/X509/CertificateStore.hs --replace \
              '${original}' '${replacement}'
          '';
        });
        # plot              = self.callCabal2nix "plot" plot {};
  
        # diagrams-cairo    = nixpkgs.haskell.lib.doJailbreak super.diagrams-cairo;
  
negative.code:   nixpkgs = import (nixpkgs_.fetchFromGitHub {
      owner  = "NixOS";
      repo   = "nixpkgs";
      rev    = "07bc1ddacebcc9587e6f4d7e05d27350e6cf23e3";
      sha256 = "1zh9551vb8pl1sscgh3n3hd7l4wb0yf4hryaz7ay5h97ljawg8hq";
    }) {};
    inherit (builtins) any elem filterSource listToAttrs;
    lib = nixpkgs.lib;
  