Fix for indexing synthetic getter/setter references.

pkg/analyzer/test/src/summary/index_unit_test.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:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
@@ skipping 683 matching lines @@
     assertThat(field)..isWrittenAt('field});', true);
     // m()
     assertThat(setter)..isReferencedAt('field = 2; // nq', false);
     assertThat(getter)..isReferencedAt('field); // nq', false);
     // main()
     assertThat(setter)..isReferencedAt('field = 3; // q', true);
     assertThat(getter)..isReferencedAt('field); // q', true);
     assertThat(field)..isReferencedAt('field: 4', true);
   }
 
+  void test_isReferencedBy_FieldElement_multiple() {
+    _indexTestUnit('''
+class A {
+  var aaa;
+  var bbb;
+  A(this.aaa, this.bbb) {}
+  m() {
+    print(aaa);
+    aaa = 1;
+    print(bbb);
+    bbb = 2;
+  }
+}
+''');
+    // aaa
+    {
+      FieldElement field = findElement('aaa');
+      PropertyAccessorElement getter = field.getter;
+      PropertyAccessorElement setter = field.setter;
+      assertThat(field)..isWrittenAt('aaa, ', true);
+      assertThat(getter)..isReferencedAt('aaa);', false);
+      assertThat(setter)..isReferencedAt('aaa = 1;', false);
+    }
+    // bbb
+    {
+      FieldElement field = findElement('bbb');
+      PropertyAccessorElement getter = field.getter;
+      PropertyAccessorElement setter = field.setter;
+      assertThat(field)..isWrittenAt('bbb) {}', true);
+      assertThat(getter)..isReferencedAt('bbb);', false);
+      assertThat(setter)..isReferencedAt('bbb = 2;', false);
+    }
+  }
+
   void test_isReferencedBy_FunctionElement() {
     _indexTestUnit('''
 foo() {}
 main() {
   print(foo);
   print(foo());
 }
 ''');
     FunctionElement element = findElement('foo');
     assertThat(element)
@@ skipping 422 matching lines @@
   final bool isQualified;
 
   _Relation(this.kind, this.offset, this.length, this.isQualified);
 
   @override
   String toString() {
     return '_Relation{kind: $kind, offset: $offset, length: $length, '
         'isQualified: $isQualified}';
   }
 }