Support accessing the parameter element when there is no name

pkg/analyzer/lib/src/dart/ast/ast.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.ast;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/syntactic_entity.dart';
@@ skipping 5813 matching lines @@
   }
 
   @override
   Iterable<SyntacticEntity> get childEntities => new ChildEntities()
     ..addAll(metadata)
     ..add(typedefKeyword)
     ..add(name)
     ..add(_typeParameters)
     ..add(equals)
     ..add(_functionType);
+
   @override
-  Element get element => null;
+  Element get element => name.staticElement;
 
   @override
   GenericFunctionType get functionType => _functionType;
 
   @override
   void set functionType(GenericFunctionType functionType) {
     _functionType = _becomeParentOf(functionType as AstNodeImpl);
   }
 
   @override
   TypeParameterList get typeParameters => _typeParameters;
 
   @override
   void set typeParameters(TypeParameterList typeParameters) {
     _typeParameters = _becomeParentOf(typeParameters as AstNodeImpl);
   }
 
   @override
   dynamic/*=E*/ accept/*<E>*/(AstVisitor/*<E>*/ visitor) {
     return visitor.visitGenericTypeAlias(this);
   }
 
-  // TODO: implement element
   @override
   void visitChildren(AstVisitor visitor) {
     super.visitChildren(visitor);
     name?.accept(visitor);
     _typeParameters?.accept(visitor);
     _functionType?.accept(visitor);
   }
 }
 
 /**
@@ skipping 3363 matching lines @@
    * `null` if no keyword was used.
    */
   Token keyword;
 
   /**
    * The name of the declared type of the parameter, or `null` if the parameter
    * does not have a declared type.
    */
   TypeAnnotation _type;
 
+  @override
+  ParameterElement element;
+
   /**
    * Initialize a newly created formal parameter. Either or both of the
    * [comment] and [metadata] can be `null` if the parameter does not have the
    * corresponding attribute. The [keyword] can be `null` if a type was
    * specified. The [type] must be `null` if the keyword is 'var'.
    */
   SimpleFormalParameterImpl(
       CommentImpl comment,
       List<Annotation> metadata,
       Token covariantKeyword,
@@ skipping 17 matching lines @@
       return _type.beginToken;
     }
     return identifier.beginToken;
   }
 
   @override
   Iterable<SyntacticEntity> get childEntities =>
       super._childEntities..add(keyword)..add(_type)..add(identifier);
 
   @override
-  Token get endToken => identifier.endToken;
+  Token get endToken => identifier?.endToken ?? type?.endToken;
 
   @override
   bool get isConst => keyword?.keyword == Keyword.CONST;
 
   @override
   bool get isFinal => keyword?.keyword == Keyword.FINAL;
 
   @override
   TypeAnnotation get type => _type;
 
@@ skipping 2191 matching lines @@
 
   @override
   dynamic/*=E*/ accept/*<E>*/(AstVisitor/*<E>*/ visitor) =>
       visitor.visitYieldStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _expression?.accept(visitor);
   }
 }