anchor.diff:      system = mkOption {
         type = types.str;
         example = "i686-linux";
  -      description = ''
  +      default =
  +        if opt.hostPlatform.isDefined
  +        then
  +          throw ''
  +            Neither ${opt.system} nor any other option in nixpkgs.* is meant
  +            to be read by modules and configurations.
  +            Use pkgs.stdenv.hostPlatform instead.
  +          ''
  +        else
  +          throw ''
  +            Neither ${opt.hostPlatform} nor or the legacy option ${opt.system} has been set.
  +            You can set ${opt.hostPlatform} in hardware-configuration.nix by re-running
  +            a recent version of nixos-generate-config.
  +            The option ${opt.system} is still fully supported for NixOS 22.05 interoperability,
  +            but will be deprecated in the future, so we recommend to set ${opt.hostPlatform}.
  +          '';
  +      defaultText = lib.literalMD ''
  +        Traditionally `builtins.currentSystem`, but unset when invoking NixOS through `lib.nixosSystem`.
  +      '';
  +      description = ''
  +        This option does not need to be specified for NixOS configurations
  +        with a recently generated <literal>hardware-configuration.nix</literal>.
  +
           Specifies the Nix platform type on which NixOS should be built.
           It is better to specify <code>nixpkgs.localSystem</code> instead.
           <programlisting>
  
positive.code:       defaultText = literalExpression
          ''(import "''${nixos}/../lib").lib.systems.examples.aarch64-multiplatform'';
        description = ''
          Specifies the platform on which NixOS should be built. When
          <code>nixpkgs.crossSystem</code> is unset, it also specifies
          the platform <emphasis>for</emphasis> which NixOS should be
  
negative.code:       default = null;
        example = { system = "aarch64-linux"; config = "aarch64-unknown-linux-gnu"; };
        description = ''
          Systems with a recently generated <literal>hardware-configuration.nix</literal>
          may instead specify <emphasis>only</emphasis> <option>nixpkgs.buildPlatform</option>,
          or fall back to removing the <option>nixpkgs.hostPlatform</option> line from the generated config.
  
          Specifies the platform for which NixOS should be
          built. Specify this only if it is different from
          <code>nixpkgs.localSystem</code>, the platform
  