Fix for regions reported with multiple targets.

pkg/analysis_server/lib/src/domains/analysis/navigation.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 domains.analysis.navigation;
 
 import 'dart:collection';
 
 import 'package:analysis_server/plugin/analysis/navigation/navigation_core.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analyzer/src/generated/engine.dart'
     show AnalysisContext, AnalysisEngine;
 import 'package:analyzer/src/generated/java_engine.dart' show CaughtException;
-import 'package:analyzer/src/generated/source.dart' show Source;
+import 'package:analyzer/src/generated/source.dart' show Source, SourceRange;
 
 /**
  * Compute all known navigation information for the given part of [source].
  */
 NavigationCollectorImpl computeNavigation(AnalysisServer server,
     AnalysisContext context, Source source, int offset, int length) {
   NavigationCollectorImpl collector = new NavigationCollectorImpl();
   List<NavigationContributor> contributors =
       server.serverPlugin.navigationContributors;
   for (NavigationContributor contributor in contributors) {
     try {
       contributor.computeNavigation(collector, context, source, offset, length);
     } catch (exception, stackTrace) {
       AnalysisEngine.instance.logger.logError(
           'Exception from navigation contributor: ${contributor.runtimeType}',
           new CaughtException(exception, stackTrace));
     }
   }
-  collector.sortRegions();
+  collector.createRegions();
   return collector;
 }
 
 /**
  * A concrete implementation of  [NavigationCollector].
  */
 class NavigationCollectorImpl implements NavigationCollector {
   /**
    * A list of navigation regions.
    */
   final List<protocol.NavigationRegion> regions = <protocol.NavigationRegion>[];
+  final Map<SourceRange, List<int>> regionMap =
+      new HashMap<SourceRange, List<int>>();
 
   /**
    * All the unique targets referenced by [regions].
    */
   final List<protocol.NavigationTarget> targets = <protocol.NavigationTarget>[];
   final Map<Pair<protocol.ElementKind, protocol.Location>, int> targetMap =
       new HashMap<Pair<protocol.ElementKind, protocol.Location>, int>();
 
   /**
    * All the unique files referenced by [targets].
    */
   final List<String> files = <String>[];
   final Map<String, int> fileMap = new HashMap<String, int>();
 
   @override
   void addRegion(int offset, int length, protocol.ElementKind targetKind,
       protocol.Location targetLocation) {
+    SourceRange range = new SourceRange(offset, length);
+    // prepare targets
+    List<int> targets = regionMap[range];
+    if (targets == null) {
+      targets = <int>[];
+      regionMap[range] = targets;
+    }
+    // add new target
     int targetIndex = _addTarget(targetKind, targetLocation);
-    protocol.NavigationRegion region =
-        new protocol.NavigationRegion(offset, length, <int>[targetIndex]);
-    regions.add(region);
+    targets.add(targetIndex);
   }
 
-  void sortRegions() {
+  void createRegions() {
+    regionMap.forEach((range, targets) {
+      protocol.NavigationRegion region =
+          new protocol.NavigationRegion(range.offset, range.length, targets);
+      regions.add(region);
+    });
     regions.sort((a, b) {
       return a.offset - b.offset;
     });
   }
 
   int _addFile(String file) {
     int index = fileMap[file];
     if (index == null) {
       index = files.length;
       files.add(file);
@@ skipping 16 matching lines @@
           location.offset,
           location.length,
           location.startLine,
           location.startColumn);
       targets.add(target);
       targetMap[pair] = index;
     }
     return index;
   }
 }