anchor.diff:  
       Cache.releaseLockEarly();
   
  -    // Do some early error checks for hot mode.
  -    bool hotMode = argResults['hot'];
  +    // Enable hot mode by default if ``--no-hot` was not passed and we are in
  +    // debug mode.
  +    final bool hotMode = shouldUseHotMode();
   
       if (hotMode) {
  -      if (getBuildMode() != BuildMode.debug) {
  -        printError('Hot mode only works with debug builds.');
  -        return 1;
  -      }
         if (!deviceForCommand.supportsHotMode) {
  -        printError('Hot mode is not supported by this device.');
  +        printError('Hot mode is not supported by this device. '
  +                   'Run with --no-hot.');
           return 1;
         }
       }
  
positive.code: 
      // Option to enable hot reloading.
      argParser.addFlag('hot',
                        negatable: false,
                        defaultsTo: false,
                        help: 'Run with support for hot reloading.');
  
      // Option to write the pid to a file.
  
negative.code:   String get usagePath {
      Device device = deviceForCommand;
  
      String command = shouldUseHotMode() ? 'hotrun' : name;
  
      if (device == null)
        return command;
  