{
  lib,
  haskell,
  haskellPackages,
  runCommand,
}:

let
  localRaw = haskellPackages.callPackage ./generated.nix { };
in
lib.recurseIntoAttrs rec {

  helloFromCabalSdist = haskellPackages.buildFromCabalSdist haskellPackages.hello;

  # A more complicated example with a cabal hook.
  hercules-ci-cnix-store = haskellPackages.buildFromCabalSdist haskellPackages.hercules-ci-cnix-store;

  localFromCabalSdist = haskellPackages.buildFromCabalSdist localRaw;

  # This test makes sure that localHasNoDirectReference can actually fail if
  # it doesn't do anything. If this test fails, either the test setup was broken,
  # or Haskell packaging has changed the way `src` is treated in such a way that
  # either the test or the design of `buildFromCabalSdist` needs to be reconsidered.
  assumptionLocalHasDirectReference =
    runCommand "localHasDirectReference"
      {
        drvPath = builtins.unsafeDiscardOutputDependency localRaw.drvPath;
      }
      ''
        grep ${localRaw.src} $drvPath >/dev/null
        touch $out
      '';

  localHasNoDirectReference =
    runCommand "localHasNoDirectReference"
      {
        drvPath = builtins.unsafeDiscardOutputDependency localFromCabalSdist.drvPath;
      }
      ''
        grep -v ${localRaw.src} $drvPath >/dev/null
        touch $out
      '';
}