AnalysisDriver.createWorkOrderForResult() should check AnalysisContext.aboutToComputeResult() first.

pkg/analyzer/lib/src/task/driver.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.src.task.driver;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
@@ skipping 147 matching lines @@
    */
   WorkOrder createWorkOrderForResult(
       AnalysisTarget target, ResultDescriptor result) {
     CacheEntry entry = context.getCacheEntry(target);
     CacheState state = entry.getState(result);
     if (state == CacheState.VALID ||
         state == CacheState.ERROR ||
         state == CacheState.IN_PROCESS) {
       return null;
     }
+    if (context.aboutToComputeResult(entry, result)) {
+      return null;
+    }
     TaskDescriptor taskDescriptor = taskManager.findTask(target, result);
     if (taskDescriptor == null) {
       return null;
     }
     try {
       WorkItem workItem =
           new WorkItem(context, target, taskDescriptor, result, 0, null);
       return new WorkOrder(taskManager, workItem);
     } catch (exception, stackTrace) {
       throw new AnalysisException(
@@ skipping 679 matching lines @@
   final TaskManager taskManager;
 
   _WorkOrderDependencyWalker(this.taskManager, WorkItem startingNode)
       : super(startingNode);
 
   @override
   WorkItem getNextInput(WorkItem node, List<WorkItem> skipInputs) {
     return node.gatherInputs(taskManager, skipInputs);
   }
 }