anchor.diff:    static Map<String, TaskInput> buildInputs(AnalysisTarget target) {
       Source source = target;
       Map<String, TaskInput> inputs = <String, TaskInput>{};
  +    inputs[LINE_INFO_INPUT] = LINE_INFO.of(source);
  +    inputs[PARSED_UNIT_INPUT] = PARSED_UNIT.of(source);
       EnginePlugin enginePlugin = AnalysisEngine.instance.enginePlugin;
       // for Source
       for (ResultDescriptor result in enginePlugin.dartErrorsForSource) {
  
positive.code:   static final TaskDescriptor DESCRIPTOR = new TaskDescriptor('DartErrorsTask',
        createTask, buildInputs, <ResultDescriptor>[DART_ERRORS]);
  
    // Prefix for comments ignoring error codes.
    static const String _normalizedIgnorePrefix = '//#ignore:';
  
  
negative.code:     // Sort errors.
      errors.sort((AnalysisError e1, AnalysisError e2) => e1.offset - e2.offset);
  
      CompilationUnit cu = getRequiredInput(PARSED_UNIT_INPUT);
      Token token = cu.beginToken;
      LineInfo lineInfo = getRequiredInput(LINE_INFO_INPUT);
  
      int errorIndex = 0;
  
  