_: pkgs:

let
  simpleCabalBuilder = self: name:
      self.callCabal2nix name pkgs.sources.${name} {};
  buildCabal = self: name: subdir:
    if isNull subdir then
      self.callCabal2nix name pkgs.sources.${name} {}
    else
      self.callCabal2nix name (pkgs.sources.${name} + "/${subdir}") {};
in rec
{
  pinnedDeps = builtins.attrNames
    (builtins.removeAttrs pkgs.sources ["__functor"]);
  overridePinnedDeps = builder: pkgs.lib.genAttrs pinnedDeps builder;

  # Modifies a derivation with our source and version, keeping old build
  # rules. This will fail if build steps have changed, or if no build
  # rules are available upstream..
  overrideSource = depName: pkgs.${depName}.overrideAttrs (old: old // rec {
    name = "${depName}-${version}";
    version = pkgs.sources.${depName}.version or pkgs.sources.${depName}.rev;
    src = pkgs.sources.${depName};
  });

  haskell = pkgs.haskell // {
    packages = pkgs.haskell.packages // {
      ghc865 = pkgs.haskell.packages.ghc865.override (old: {
        overrides = with pkgs.pkgs.haskell.lib; self: super:
          overridePinnedDeps (simpleCabalBuilder self) // {
          acid-state = dontCheck super.acid-state; # mac: "too many open files"
          ghcjs-base = null; # otherwise ghc tries to build this via overridePinnedDeps
          servant-auth = buildCabal self "servant-auth" "servant-auth";
          servant-server = doJailbreak super.servant-server;
          temporary = dontCheck super.temporary;
          wai-middleware-metrics = dontCheck super.wai-middleware-metrics;
        };
      });
      ghcjs86 = pkgs.haskell.packages.ghcjs86.override (old: {
        overrides = with pkgs.haskell.lib; self: super:
          overridePinnedDeps (simpleCabalBuilder self) // {
          Glob = dontCheck super.Glob;
          QuickCheck = dontCheck super.QuickCheck;
          aeson = dontCheck super.aeson;
          base-compat-batteries = dontCheck super.base-compat-batteries;
          clay = dontCheck super.clay;
          comonad = dontCheck super.comonad;
          ghcjs-base = dontCheck (simpleCabalBuilder self "ghcjs-base");
          jsaddle-warp = dontCheck (self.callCabal2nix "jsaddle-warp" "${pkgs.sources.jsaddle}/jsaddle-warp" {});
          http-types = dontCheck super.http-types;
          network-uri= dontCheck super.network-uri;
          scientific = dontCheck super.scientific; # takes forever
          servant = dontCheck super.servant;
          servant-auth = buildCabal self "servant-auth" "servant-auth";
          tasty-quickcheck = dontCheck super.tasty-quickcheck;
          temporary = dontCheck super.temporary;
          time-compat = dontCheck super.time-compat;
          vector = dontCheck super.vector;
        };
      });
    };
  };
}