Nix snippets not used

eachNewer.nix

  eachNewer = lib.filterAttrs (name: updatedPackage:
    let
      verNixpkgs = pkgs0.${name}.version;
      verOverride = updatedPackage.version;
    in if lib.versionOlder verNixpkgs verOverride then
      true
    else
      lib.warn ''
        package `${name}` has an overlay but the version in Nixpkgs is newer
        (${verNixpkgs} >= ${verOverride})
        the derivation in question will be selected from Nixpkgs, without the overlay
      '' false);

pathStem.nix

  pathStem = path:
    lib.findFirst (name: name != null) null
    (builtins.match "(.+)\\..*|(.+)" (baseNameOf path));