anchor.diff:  import 'package:analysis_server/plugin/protocol/protocol.dart';
   import 'package:analysis_server/src/analysis_server.dart';
   import 'package:analysis_server/src/constants.dart';
  -import 'package:analysis_server/src/context_manager.dart';
   import 'package:analysis_server/src/provisional/completion/completion_core.dart'
       show CompletionRequest, CompletionResult;
   import 'package:analysis_server/src/services/completion/completion_core.dart';
   import 'package:analysis_server/src/services/completion/completion_manager.dart';
  -import 'package:analysis_server/src/services/search/search_engine.dart';
   import 'package:analyzer/src/generated/engine.dart';
   import 'package:analyzer/src/generated/source.dart';
   
  
positive.code: 
    @override
    Response handleRequest(Request request) {
      if (searchEngine == null) {
        return new Response.noIndexGenerated(request);
      }
      return runZoned(() {
  
negative.code:           exception,
            stackTrace);
      });
    }
  
    /**
  