Issue 26034#3. Fix for indexing references to synthetic fields.

pkg/analyzer/lib/src/summary/idl.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.
 
 /**
  * This file is an "idl" style description of the summary format.  It
  * contains abstract classes which declare the interface for reading data from
  * summaries.  It is parsed and transformed into code that implements the
  * summary format.
  *
@@ skipping 276 matching lines @@
    * Not a synthetic element.
    */
   notSynthetic,
 
   /**
    * The unnamed synthetic constructor a class element.
    */
   constructor,
 
   /**
+   * The synthetic field element.
+   */
+  field,
+
+  /**
    * The synthetic getter of a property introducing element.
    */
   getter,
 
   /**
    * The synthetic setter of a property introducing element.
    */
   setter,
 
   /**
@@ skipping 2112 matching lines @@
    */
   @Id(11)
   int get visibleLength;
 
   /**
    * If a local variable, the beginning of the visible range; zero otherwise.
    */
   @Id(12)
   int get visibleOffset;
 }