anchor.diff:  library polymorphic.grind;
   
  +import "dart:io";
  +
   import "package:grinder/grinder.dart";
  +import "package:yaml/yaml.dart";
   
   void main(List<String> args) {
     task("clean", defaultClean);
  
positive.code:     "bin/polymorphic.dart",
      "-o",
      "build/out/PolymorphicBot.dart",
      "-m"
    ];
    
    return runProcessAsync(context, "dart2js", arguments: args).then((_) {
  
negative.code: 
  package(GrinderContext context) {
    ensureOutDirectory();
    var pubspec = loadYaml(new File("pubspec.yaml").readAsStringSync());
    var version = pubspec["version"];
    
    var args = [
      "--enable-experimental-mirrors",
  