anchor.diff:        case AnalysisSeverity.none:
           return writtenError.severity;
       }
  -    return null;
     }
   
     String get type => writtenError.type;
  
positive.code:   AnalysisServer(
      this.sdkPath,
      this.directories, {
      @required FileSystem fileSystem,
      @required ProcessManager processManager,
      @required Logger logger,
      @required Platform platform,
      @required Terminal terminal,
      String protocolTrafficLog,
    }) : _fileSystem = fileSystem,
         _processManager = processManager,
         _logger = logger,
  
negative.code:       'method': method,
        'params': params,
      });
      _process?.stdin.writeln(message);
      _logger.printTrace('==> $message');
    }
  
  