Make reference 0 consistent between AST-based and element-based summaries.

pkg/analyzer/test/src/summary/summary_common.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.test.src.summary.summary_common;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
@@ skipping 8241 matching lines @@
   }
 
   test_public_namespace_of_part() {
     addNamedSource('/a.dart', 'part of foo; class C {}');
     serializeLibraryText('library foo; part "a.dart";');
     expect(unlinkedUnits[0].publicNamespace.names, isEmpty);
     expect(unlinkedUnits[1].publicNamespace.names, hasLength(1));
     expect(unlinkedUnits[1].publicNamespace.names[0].name, 'C');
   }
 
+  test_reference_zero() {
+    // Element zero of the references table should be populated in a standard
+    // way.
+    serializeLibraryText('');
+    UnlinkedReference unlinkedReference0 = unlinkedUnits[0].references[0];
+    expect(unlinkedReference0.name, '');
+    expect(unlinkedReference0.prefixReference, 0);
+    LinkedReference linkedReference0 = linked.units[0].references[0];
+    expect(linkedReference0.containingReference, 0);
+    expect(linkedReference0.dependency, 0);
+    expect(linkedReference0.kind, ReferenceKind.unresolved);
+    expect(linkedReference0.localIndex, 0);
+    expect(linkedReference0.name, '');
+    expect(linkedReference0.numTypeParameters, 0);
+    expect(linkedReference0.unit, 0);
+  }
+
   test_setter_documented() {
     String text = '''
 // Extra comment so doc comment offset != 0
 /**
  * Docs
  */
 void set f(value) {}''';
     UnlinkedExecutable executable =
         serializeExecutableText(text, executableName: 'f=');
     expect(executable.documentationComment, isNotNull);
@@ skipping 1106 matching lines @@
 class _PrefixExpectation {
   final ReferenceKind kind;
   final String name;
   final String absoluteUri;
   final String relativeUri;
   final int numTypeParameters;
 
   _PrefixExpectation(this.kind, this.name,
       {this.absoluteUri, this.relativeUri, this.numTypeParameters: 0});
 }