Support accessing the parameter element when there is no name

pkg/analyzer/lib/src/dart/ast/utilities.dart

 // Copyright (c) 2014, 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.src.dart.ast.utilities;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
@@ skipping 6410 matching lines @@
   @override
   bool visitShowCombinator(ShowCombinator node) {
     ShowCombinator toNode = this._toNode as ShowCombinator;
     return _and(_isEqualTokens(node.keyword, toNode.keyword),
         _isEqualNodeLists(node.shownNames, toNode.shownNames));
   }
 
   @override
   bool visitSimpleFormalParameter(SimpleFormalParameter node) {
     SimpleFormalParameter toNode = this._toNode as SimpleFormalParameter;
-    return _and(
+    if (_and(
         _isEqualNodes(node.documentationComment, toNode.documentationComment),
         _isEqualNodeLists(node.metadata, toNode.metadata),
         _isEqualTokens(node.keyword, toNode.keyword),
         _isEqualNodes(node.type, toNode.type),
-        _isEqualNodes(node.identifier, toNode.identifier));
+        _isEqualNodes(node.identifier, toNode.identifier))) {
+      (toNode as SimpleFormalParameterImpl).element = node.element;
+      return true;
+    }
+    return false;
   }
 
   @override
   bool visitSimpleIdentifier(SimpleIdentifier node) {
     SimpleIdentifier toNode = this._toNode as SimpleIdentifier;
     if (_isEqualTokens(node.token, toNode.token)) {
       toNode.staticElement = node.staticElement;
       toNode.staticType = node.staticType;
       toNode.propagatedElement = node.propagatedElement;
       toNode.propagatedType = node.propagatedType;
@@ skipping 2924 matching lines @@
     if (node.star != null) {
       sink.write("yield* ");
     } else {
       sink.write("yield ");
     }
     safelyVisitNode(node.expression);
     sink.write(";");
     return null;
   }
 }