Fix for indexing synthetic elements.

pkg/analysis_server/lib/src/services/index2/index2.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 287 matching lines @@
   /**
    * Return the [element]'s identifier in the [index] or `-1` if the
    * [element] is not referenced in the [index].
    */
   int findElementId(Element element) {
     // Find the id of the element's unit.
     int unitId = getUnitId(element);
     if (unitId == -1) {
       return -1;
     }
-    // Prepare the offset of the element.
-    int offset = element.nameOffset;
-    if (element is LibraryElement || element is CompilationUnitElement) {
-      offset = 0;
-    }
+    // Prepare information about the element.
+    ElementInfo info = PackageIndexAssembler.newElementInfo(unitId, element);
     // Find the first occurrence of an element with the same offset.
-    int elementId = _findFirstOccurrence(index.elementOffsets, offset);
+    int elementId = _findFirstOccurrence(index.elementOffsets, info.offset);
     if (elementId == -1) {
       return -1;
     }
     // Try to find the element id using offset, unit and kind.
-    IndexSyntheticElementKind kind =
-        PackageIndexAssembler.getIndexElementKind(element);
     for (;
         elementId < index.elementOffsets.length &&
-            index.elementOffsets[elementId] == offset;
+            index.elementOffsets[elementId] == info.offset;
         elementId++) {
       if (index.elementUnits[elementId] == unitId &&
-          index.elementKinds[elementId] == kind) {
+          index.elementKinds[elementId] == info.kind) {
         return elementId;
       }
     }
     return -1;
   }
 
   /**
    * Complete with a list of locations where elements of the given [kind] with
    * names satisfying the given [regExp] are defined.
    */
@@ skipping 194 matching lines @@
         i < unitIndex.usedNames.length && unitIndex.usedNames[i] == nameId;
         i++) {
       unitLibraryUri ??= packageRequester.getUnitLibraryUri(unitIndex.unit);
       unitUnitUri ??= packageRequester.getUnitUnitUri(unitIndex.unit);
       locations.add(new Location(context, unitLibraryUri, unitUnitUri,
           unitIndex.usedNameOffsets[i], name.length, true));
     }
     return locations;
   }
 }