anchor.diff:            vim-rhubarb
             vim-scala
             vim-surround
  +          vim-test-custom
             vimux
  -          custom-vim-test
           ];
         };
       };
  
positive.code:     };
    };
  
    custom-vim-test = buildVimPluginFrom2Nix {
      name = "vim-test-2019-01-31";
      src = fetchFromGitHub {
        owner = "janko-m";
  
negative.code:           vim-airline
            vim-airline-themes
            vim-easy-align
            vim-easymotion
            vim-fugitive
            vim-lsc
            vim-markdown
  