self: super:

let
 claySrc = super.pkgs.fetchFromGitHub {
    owner = "sebastiaanvisser";
    repo = "clay";
    rev = "cc7729b1b42a79e261091ff7835f7fc2a7ae3cee";
    sha256 = "1vd67976lvi5l4qq18zy6j44apynkl44ps04p8vwfx4gzr895dyp";
  };
in {
  haskell = super.haskell // {
    packages = super.haskell.packages // {
      ghc865 = super.haskell.packages.ghc865.override (old: {
        overrides = with super.pkgs.haskell.lib; self: super: {
          clay = self.callCabal2nix "clay" claySrc {};
          wai-middleware-metrics = dontCheck super.wai-middleware-metrics;
        };
      });
      ghcjs = super.haskell.packages.ghcjs.override (old: {
        overrides = with super.haskell.lib; self: super: {
          QuickCheck = dontCheck super.QuickCheck;
          base-compat-batteries = dontCheck super.http-types;
          clay = dontCheck (self.callCabal2nix "clay" claySrc {});
          comonad = dontCheck super.comonad;
          http-types = dontCheck super.http-types;
          network-uri= dontCheck super.network-uri;
          scientific = dontCheck super.scientific; # takes forever
          servant = dontCheck super.servant;
          tasty-quickcheck = dontCheck super.tasty-quickcheck;
          time-compat = dontCheck super.time-compat;
        };
      });
    };
  };
}