Support accessing the parameter element when there is no name

pkg/analyzer/lib/src/generated/declaration_resolver.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.
 
 library analyzer.src.generated.declaration_resolver;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/exception/exception.dart';
+import 'package:analyzer/src/dart/ast/ast.dart';
 import 'package:analyzer/src/dart/element/builder.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 
 /**
  * A visitor that resolves declarations in an AST structure to already built
  * elements.
  *
  * The resulting AST must have everything resolved that would have been resolved
@@ skipping 93 matching lines @@
 
   @override
   Object visitDeclaredIdentifier(DeclaredIdentifier node) {
     // Declared identifiers can only occur inside executable elements.
     _walker.elementBuilder.visitDeclaredIdentifier(node);
     return null;
   }
 
   @override
   Object visitDefaultFormalParameter(DefaultFormalParameter node) {
+    NormalFormalParameter normalParameter = node.parameter;
     ParameterElement element =
-        _match(node.parameter.identifier, _walker.getParameter());
+        _match(normalParameter.identifier, _walker.getParameter());
+    if (normalParameter is SimpleFormalParameterImpl) {
+      normalParameter.element = node.identifier.staticElement;
+    }
     Expression defaultValue = node.defaultValue;
     if (defaultValue != null) {
       _walk(
           new ElementWalker.forExecutable(element.initializer, _enclosingUnit),
           () {
         defaultValue.accept(this);
       });
     }
     _walk(new ElementWalker.forParameter(element), () {
-      node.parameter.accept(this);
+      normalParameter.accept(this);
     });
     _resolveMetadata(node, node.metadata, element);
     return null;
   }
 
   @override
   Object visitEnumDeclaration(EnumDeclaration node) {
     ClassElement element = _match(node.name, _walker.getEnum());
     _walk(new ElementWalker.forClass(element), () {
       for (EnumConstantDeclaration constant in node.constants) {
@@ skipping 211 matching lines @@
   Object visitPartOfDirective(PartOfDirective node) {
     node.element = _enclosingUnit.library;
     return super.visitPartOfDirective(node);
   }
 
   @override
   Object visitSimpleFormalParameter(SimpleFormalParameter node) {
     if (node.parent is! DefaultFormalParameter) {
       ParameterElement element =
           _match(node.identifier, _walker.getParameter());
+      (node as SimpleFormalParameterImpl).element =
+          node.identifier.staticElement;
       _walk(new ElementWalker.forParameter(element), () {
         super.visitSimpleFormalParameter(node);
       });
       _resolveMetadata(node, node.metadata, element);
       return null;
     } else {
       return super.visitSimpleFormalParameter(node);
     }
   }
 
@@ skipping 355 matching lines @@
 class _ElementMismatchException extends AnalysisException {
   /**
    * Creates an exception to refer to the given [compilationUnit], [element],
    * and [cause].
    */
   _ElementMismatchException(
       CompilationUnitElement compilationUnit, Element element,
       [CaughtException cause = null])
       : super('Element mismatch in $compilationUnit at $element', cause);
 }