anchor.diff:    test_nvim_with_vim_nix_using_pathogen = neovim.override {
       configure.pathogen.pluginNames = [ "vim-nix" ];
     };
  +
  +  # regression test for https://github.com/NixOS/nixpkgs/issues/53112
  +  # The user may have specified their own plugins which may not be formatted
  +  # exactly as the generated ones. In particular, they may not have the `pname`
  +  # attribute.
  +  test_vim_with_custom_plugin = vim_configurable.customize {
  +    name = "vim_with_custom_plugin";
  +    vimrcConfig.vam.knownPlugins =
  +      vimPlugins // ({
  +        "vim-trailing-whitespace" = buildVimPluginFrom2Nix {
  +          name = "vim-trailing-whitespace";
  +          src = fetchFromGitHub {
  +            owner = "bronson";
  +            repo = "vim-trailing-whitespace";
  +            rev = "4c596548216b7c19971f8fc94e38ef1a2b55fee6";
  +            sha256 = "0f1cpnp1nxb4i5hgymjn2yn3k1jwkqmlgw1g02sq270lavp2dzs9";
  +          };
  +          dependencies = [];
  +        };
  +      });
  +    vimrcConfig.vam.pluginDictionaries = [ { names = [ "vim-trailing-whitespace" ]; } ];
  +  };
   }
  
positive.code:       (let
          knownPlugins = vam.knownPlugins or vimPlugins;
  
          plugins = findDependenciesRecursively knownPlugins (lib.concatMap vamDictToNames vam.pluginDictionaries);
  
          # Vim almost reads JSON, so eventually JSON support should be added to Nix
          # TODO: proper quoting
  
negative.code:       (let
          knownPlugins = pathogen.knownPlugins or vimPlugins;
  
          plugins = findDependenciesRecursively (map (pluginToDrv knownPlugins) pathogen.pluginNames);
  
          pluginsEnv = buildEnv {
            name = "pathogen-plugin-env";
  