Introduce CompletionTarget to take the place of the Node being completed.

pkg/analyzer/lib/src/generated/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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.ast;
 
 import 'dart:collection';
@@ skipping 33 matching lines @@
    * @param strings the strings that are implicitly concatenated
    */
   AdjacentStrings(List<StringLiteral> strings) {
     _strings = new NodeList<StringLiteral>(this, strings);
   }
 
   @override
   Token get beginToken => _strings.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()..addAll(_strings);
+
+  @override
   Token get endToken => _strings.endToken;
 
   /**
    * Return the strings that are implicitly concatenated.
    *
    * @return the strings that are implicitly concatenated
    */
   NodeList<StringLiteral> get strings => _strings;
 
   @override
@@ skipping 105 matching lines @@
    * @return the comment and annotations associated with this node in the order in which they
    *         appeared in the original source
    */
   List<AstNode> get sortedCommentAndAnnotations {
     return <AstNode>[]
         ..add(_comment)
         ..addAll(_metadata)
         ..sort(AstNode.LEXICAL_ORDER);
   }
 
+  ChildEntities get _childEntities {
+    ChildEntities result = new ChildEntities();
+    if (_commentIsBeforeAnnotations()) {
+      result
+          ..add(_comment)
+          ..addAll(_metadata);
+    } else {
+      result.addAll(sortedCommentAndAnnotations);
+    }
+    return result;
+  }
+
   @override
   void visitChildren(AstVisitor visitor) {
     if (_commentIsBeforeAnnotations()) {
       safelyVisitChild(_comment, visitor);
       _metadata.accept(visitor);
     } else {
       for (AstNode child in sortedCommentAndAnnotations) {
         child.accept(visitor);
       }
     }
@@ skipping 99 matching lines @@
    *
    * @param arguments the arguments to the constructor being invoked
    */
   void set arguments(ArgumentList arguments) {
     _arguments = becomeParentOf(arguments);
   }
 
   @override
   Token get beginToken => atSign;
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(atSign)
+      ..add(_name)
+      ..add(period)
+      ..add(_constructorName)
+      ..add(_arguments);
+
   /**
    * Return the name of the constructor being invoked, or `null` if this annotation is not the
    * invocation of a named constructor.
    *
    * @return the name of the constructor being invoked
    */
   SimpleIdentifier get constructorName => _constructorName;
 
   /**
    * Set the name of the constructor being invoked to the given name.
@@ skipping 132 matching lines @@
    * intermixed.
    *
    * @return the expressions producing the values of the arguments
    */
   NodeList<Expression> get arguments => _arguments;
 
   @override
   Token get beginToken => leftParenthesis;
 
   /**
+   * TODO(paulberry): Add commas.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(leftParenthesis)
+      ..addAll(_arguments)
+      ..add(rightParenthesis);
+
+  /**
    * Set the parameter elements corresponding to each of the arguments in this list to the given
    * array of parameters. The array of parameters must be the same length as the number of
    * arguments, but can contain `null` entries if a given argument does not correspond to a
    * formal parameter.
    *
    * @param parameters the parameter elements corresponding to the arguments
    */
   void set
       correspondingPropagatedParameters(List<ParameterElement> parameters) {
     if (parameters.length != _arguments.length) {
@@ skipping 118 matching lines @@
    */
   AsExpression(Expression expression, this.asOperator, TypeName type) {
     _expression = becomeParentOf(expression);
     _type = becomeParentOf(type);
   }
 
   @override
   Token get beginToken => _expression.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_expression)
+      ..add(asOperator)
+      ..add(_type);
+
+  @override
   Token get endToken => _type.endToken;
 
   /**
    * Return the expression used to compute the value being cast.
    *
    * @return the expression used to compute the value being cast
    */
   Expression get expression => _expression;
 
   /**
@@ skipping 79 matching lines @@
    */
   AssertStatement(this.keyword, this.leftParenthesis, Expression condition,
       this.rightParenthesis, this.semicolon) {
     _condition = becomeParentOf(condition);
   }
 
   @override
   Token get beginToken => keyword;
 
   /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(leftParenthesis)
+      ..add(_condition)
+      ..add(rightParenthesis)
+      ..add(semicolon);
+
+  /**
    * Return the condition that is being asserted to be `true`.
    *
    * @return the condition that is being asserted to be `true`
    */
   Expression get condition => _condition;
 
   /**
    * Set the condition that is being asserted to be `true` to the given expression.
    *
    * @param the condition that is being asserted to be `true`
@@ skipping 93 matching lines @@
    */
   MethodElement get bestElement {
     MethodElement element = propagatedElement;
     if (element == null) {
       element = staticElement;
     }
     return element;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_leftHandSide)
+      ..add(operator)
+      ..add(_rightHandSide);
+
+  @override
   Token get endToken => _rightHandSide.endToken;
 
   /**
    * Set the expression used to compute the left hand side to the given expression.
    *
    * @return the expression used to compute the left hand side
    */
   Expression get leftHandSide => _leftHandSide;
 
   /**
@@ skipping 2136 matching lines @@
   Map<String, Object> _propertyMap;
 
   /**
    * Return the first token included in this node's source range.
    *
    * @return the first token included in this node's source range
    */
   Token get beginToken;
 
   /**
+   * Iterate through all the entities (either AST nodes or tokens) which make
+   * up the contents of this node, including doc comments but excluding other
+   * comments.
+   */
+  Iterable get childEntities;
+
+  /**
    * Return the offset of the character immediately following the last character of this node's
    * source range. This is equivalent to `node.getOffset() + node.getLength()`. For a
    * compilation unit this will be equal to the length of the unit's source. For synthetic nodes
    * this will be equivalent to the node's offset (because the length is zero (0) by definition).
    *
    * @return the offset of the character just past the node's source range
    */
   int get end => offset + length;
 
   /**
@@ skipping 430 matching lines @@
 
   @override
   Token get beginToken {
     if (awaitKeyword != null) {
       return awaitKeyword;
     }
     return _expression.beginToken;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(awaitKeyword)
+      ..add(_expression);
+
+  @override
   Token get endToken => _expression.endToken;
 
   /**
    * Return the expression whose value is being waited on.
    *
    * @return the expression whose value is being waited on
    */
   Expression get expression => _expression;
 
   /**
@@ skipping 81 matching lines @@
    */
   MethodElement get bestElement {
     MethodElement element = propagatedElement;
     if (element == null) {
       element = staticElement;
     }
     return element;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_leftOperand)
+      ..add(operator)
+      ..add(_rightOperand);
+
+  @override
   Token get endToken => _rightOperand.endToken;
 
   /**
    * Return the expression used to compute the left operand.
    *
    * @return the expression used to compute the left operand
    */
   Expression get leftOperand => _leftOperand;
 
   /**
@@ skipping 108 matching lines @@
    * @param rightBracket the right curly bracket
    */
   Block(this.leftBracket, List<Statement> statements, this.rightBracket) {
     _statements = new NodeList<Statement>(this, statements);
   }
 
   @override
   Token get beginToken => leftBracket;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(leftBracket)
+      ..addAll(_statements)
+      ..add(rightBracket);
+
+  @override
   Token get endToken => rightBracket;
 
   /**
    * Return the statements contained in the block.
    *
    * @return the statements contained in the block
    */
   NodeList<Statement> get statements => _statements;
 
   @override
@@ skipping 55 matching lines @@
   /**
    * Set the block representing the body of the function to the given block.
    *
    * @param block the block representing the body of the function
    */
   void set block(Block block) {
     _block = becomeParentOf(block);
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(star)
+      ..add(_block);
+
+  @override
   Token get endToken => _block.endToken;
 
   @override
   bool get isAsynchronous {
     if (keyword == null) {
       return false;
     }
     String keywordValue = keyword.lexeme;
     return keywordValue == Parser.ASYNC;
   }
@@ skipping 36 matching lines @@
    * Initialize a newly created boolean literal.
    *
    * @param literal the token representing the literal
    * @param value the value of the literal
    */
   BooleanLiteral(this.literal, this.value);
 
   @override
   Token get beginToken => literal;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(literal);
+
   @override
   Token get endToken => literal;
 
   @override
   bool get isSynthetic => literal.isSynthetic;
 
   @override
   accept(AstVisitor visitor) => visitor.visitBooleanLiteral(this);
 
   @override
@@ skipping 96 matching lines @@
    * @param label the label associated with the statement
    * @param semicolon the semicolon terminating the statement
    */
   BreakStatement(this.keyword, SimpleIdentifier label, this.semicolon) {
     _label = becomeParentOf(label);
   }
 
   @override
   Token get beginToken => keyword;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(_label)
+      ..add(semicolon);
+
   @override
   Token get endToken => semicolon;
 
   /**
    * Return the label associated with the statement, or `null` if there is no label.
    *
    * @return the label associated with the statement
    */
   SimpleIdentifier get label => _label;
 
@@ skipping 59 matching lines @@
   Token get beginToken => _target.beginToken;
 
   /**
    * Return the cascade sections sharing the common target.
    *
    * @return the cascade sections sharing the common target
    */
   NodeList<Expression> get cascadeSections => _cascadeSections;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_target)
+      ..addAll(_cascadeSections);
+
+  @override
   Token get endToken => _cascadeSections.endToken;
 
   @override
   int get precedence => 2;
 
   /**
    * Return the target of the cascade sections.
    *
    * @return the target of the cascade sections
    */
@@ skipping 119 matching lines @@
   /**
    * Set the body of the catch block to the given block.
    *
    * @param block the body of the catch block
    */
   void set body(Block block) {
     _body = becomeParentOf(block);
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(onKeyword)
+      ..add(_exceptionType)
+      ..add(catchKeyword)
+      ..add(leftParenthesis)
+      ..add(_exceptionParameter)
+      ..add(comma)
+      ..add(_stackTraceParameter)
+      ..add(rightParenthesis)
+      ..add(_body);
+
+  @override
   Token get endToken => _body.endToken;
 
   /**
    * Return the parameter whose value will be the exception that was thrown.
    *
    * @return the parameter whose value will be the exception that was thrown
    */
   SimpleIdentifier get exceptionParameter => _exceptionParameter;
 
   /**
@@ skipping 47 matching lines @@
   @override
   void visitChildren(AstVisitor visitor) {
     safelyVisitChild(_exceptionType, visitor);
     safelyVisitChild(_exceptionParameter, visitor);
     safelyVisitChild(_stackTraceParameter, visitor);
     safelyVisitChild(_body, visitor);
   }
 }
 
 /**
+ * Helper class to allow iteration of child entities of an AST node.
+ */
+class ChildEntities extends Object with IterableMixin implements Iterable {
+  List _entities = [];
+
+  @override
+  Iterator get iterator => _entities.iterator;
+
+  /**
+   * Add an AST node or token as the next child entity, if it is not null.
+   */
+  void add(entity) {
+    if (entity != null) {
+      assert(entity is Token || entity is AstNode);
+      _entities.add(entity);
+    }
+  }
+
+  /**
+   * Add the given items as the next child entities, if [items] is not null.
+   */
+  void addAll(Iterable items) {
+    if (items != null) {
+      _entities.addAll(items);
+    }
+  }
+}
+
+/**
  * Instances of the class `ClassDeclaration` represent the declaration of a class.
  *
  * <pre>
  * classDeclaration ::=
  *     'abstract'? 'class' [SimpleIdentifier] [TypeParameterList]?
  *     ([ExtendsClause] [WithClause]?)?
  *     [ImplementsClause]?
  *     '{' [ClassMember]* '}'
  * </pre>
  */
@@ skipping 79 matching lines @@
       : super(comment, metadata) {
     _name = becomeParentOf(name);
     _typeParameters = becomeParentOf(typeParameters);
     _extendsClause = becomeParentOf(extendsClause);
     _withClause = becomeParentOf(withClause);
     _implementsClause = becomeParentOf(implementsClause);
     _members = new NodeList<ClassMember>(this, members);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(abstractKeyword)
+      ..add(classKeyword)
+      ..add(_name)
+      ..add(_typeParameters)
+      ..add(_extendsClause)
+      ..add(_withClause)
+      ..add(_implementsClause)
+      ..add(_nativeClause)
+      ..add(leftBracket)
+      ..addAll(members)
+      ..add(rightBracket);
+
+  @override
   ClassElement get element =>
       _name != null ? (_name.staticElement as ClassElement) : null;
 
   @override
   Token get endToken => rightBracket;
 
   /**
    * Return the extends clause for this class, or `null` if the class does not extend any
    * other class.
    *
@@ skipping 280 matching lines @@
       ImplementsClause implementsClause, Token semicolon)
       : super(comment, metadata, keyword, semicolon) {
     _name = becomeParentOf(name);
     _typeParameters = becomeParentOf(typeParameters);
     _superclass = becomeParentOf(superclass);
     _withClause = becomeParentOf(withClause);
     _implementsClause = becomeParentOf(implementsClause);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(keyword)
+      ..add(_name)
+      ..add(_typeParameters)
+      ..add(equals)
+      ..add(abstractKeyword)
+      ..add(_superclass)
+      ..add(_withClause)
+      ..add(_implementsClause)
+      ..add(semicolon);
+
+  @override
   ClassElement get element =>
       _name != null ? (_name.staticElement as ClassElement) : null;
 
   /**
    * Return the implements clause for this class, or `null` if there is no implements clause.
    *
    * @return the implements clause for this class
    */
   ImplementsClause get implementsClause => _implementsClause;
 
@@ skipping 165 matching lines @@
    * @param references the references embedded within the documentation comment
    */
   Comment(this.tokens, this._type, List<CommentReference> references) {
     _references = new NodeList<CommentReference>(this, references);
   }
 
   @override
   Token get beginToken => tokens[0];
 
   @override
+  Iterable get childEntities => new ChildEntities()..addAll(tokens);
+
+  @override
   Token get endToken => tokens[tokens.length - 1];
 
   /**
    * Return `true` if this is a block comment.
    *
    * @return `true` if this is a block comment
    */
   bool get isBlock => _type == CommentType.BLOCK;
 
   /**
@@ skipping 91 matching lines @@
    * @param identifier the identifier being referenced
    */
   CommentReference(this.newKeyword, Identifier identifier) {
     _identifier = becomeParentOf(identifier);
   }
 
   @override
   Token get beginToken => _identifier.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(newKeyword)
+      ..add(_identifier);
+
+  @override
   Token get endToken => _identifier.endToken;
 
   /**
    * Return the identifier being referenced.
    *
    * @return the identifier being referenced
    */
   Identifier get identifier => _identifier;
 
   /**
@@ skipping 121 matching lines @@
    * @param endToken the last token in the token stream
    */
   CompilationUnit(this.beginToken, ScriptTag scriptTag,
       List<Directive> directives, List<CompilationUnitMember> declarations,
       this.endToken) {
     _scriptTag = becomeParentOf(scriptTag);
     _directives = new NodeList<Directive>(this, directives);
     _declarations = new NodeList<CompilationUnitMember>(this, declarations);
   }
 
+  @override
+  Iterable get childEntities {
+    ChildEntities result = new ChildEntities()..add(_scriptTag);
+    if (_directivesAreBeforeDeclarations()) {
+      result
+          ..addAll(_directives)
+          ..addAll(_declarations);
+    } else {
+      result.addAll(sortedDirectivesAndDeclarations);
+    }
+    return result;
+  }
+
   /**
    * Return the declarations contained in this compilation unit.
    *
    * @return the declarations contained in this compilation unit
    */
   NodeList<CompilationUnitMember> get declarations => _declarations;
 
   /**
    * Return the directives contained in this compilation unit.
    *
@@ skipping 149 matching lines @@
       Expression thenExpression, this.colon, Expression elseExpression) {
     _condition = becomeParentOf(condition);
     _thenExpression = becomeParentOf(thenExpression);
     _elseExpression = becomeParentOf(elseExpression);
   }
 
   @override
   Token get beginToken => _condition.beginToken;
 
   /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_condition)
+      ..add(question)
+      ..add(_thenExpression)
+      ..add(colon)
+      ..add(_elseExpression);
+
+  /**
    * Return the condition used to determine which of the expressions is executed next.
    *
    * @return the condition used to determine which expression is executed next
    */
   Expression get condition => _condition;
 
   /**
    * Set the condition used to determine which of the expressions is executed next to the given
    * expression.
    *
@@ skipping 559 matching lines @@
   /**
    * Set the body of the constructor to the given function body.
    *
    * @param functionBody the body of the constructor
    */
   void set body(FunctionBody functionBody) {
     _body = becomeParentOf(functionBody);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(externalKeyword)
+      ..add(constKeyword)
+      ..add(factoryKeyword)
+      ..add(_returnType)
+      ..add(period)
+      ..add(_name)
+      ..add(_parameters)
+      ..add(separator)
+      ..addAll(initializers)
+      ..add(_redirectedConstructor)
+      ..add(_body);
+
+  @override
   Token get endToken {
     if (_body != null) {
       return _body.endToken;
     } else if (!_initializers.isEmpty) {
       return _initializers.endToken;
     }
     return _parameters.endToken;
   }
 
   @override
@@ skipping 152 matching lines @@
 
   @override
   Token get beginToken {
     if (keyword != null) {
       return keyword;
     }
     return _fieldName.beginToken;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(period)
+      ..add(_fieldName)
+      ..add(equals)
+      ..add(_expression);
+
+  @override
   Token get endToken => _expression.endToken;
 
   /**
    * Return the expression computing the value to which the field will be initialized.
    *
    * @return the expression computing the value to which the field will be initialized
    */
   Expression get expression => _expression;
 
   /**
@@ skipping 87 matching lines @@
    */
   ConstructorName(TypeName type, this.period, SimpleIdentifier name) {
     _type = becomeParentOf(type);
     _name = becomeParentOf(name);
   }
 
   @override
   Token get beginToken => _type.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_type)
+      ..add(period)
+      ..add(_name);
+
+  @override
   Token get endToken {
     if (_name != null) {
       return _name.endToken;
     }
     return _type.endToken;
   }
 
   /**
    * Return the name of the constructor, or `null` if the specified constructor is the unnamed
    * constructor.
@@ skipping 78 matching lines @@
    * @param label the label associated with the statement
    * @param semicolon the semicolon terminating the statement
    */
   ContinueStatement(this.keyword, SimpleIdentifier label, this.semicolon) {
     _label = becomeParentOf(label);
   }
 
   @override
   Token get beginToken => keyword;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(_label)
+      ..add(semicolon);
+
   @override
   Token get endToken => semicolon;
 
   /**
    * Return the label associated with the statement, or `null` if there is no label.
    *
    * @return the label associated with the statement
    */
   SimpleIdentifier get label => _label;
 
@@ skipping 74 matching lines @@
    * @param type the name of the declared type of the parameter
    * @param identifier the name of the parameter being declared
    */
   DeclaredIdentifier(Comment comment, List<Annotation> metadata, this.keyword,
       TypeName type, SimpleIdentifier identifier)
       : super(comment, metadata) {
     _type = becomeParentOf(type);
     _identifier = becomeParentOf(identifier);
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(keyword)
+      ..add(_type)
+      ..add(_identifier);
+
   @override
   LocalVariableElement get element {
     if (_identifier == null) {
       return null;
     }
     return _identifier.staticElement as LocalVariableElement;
   }
 
   @override
   Token get endToken => _identifier.endToken;
@@ skipping 117 matching lines @@
   DefaultFormalParameter(NormalFormalParameter parameter, this.kind,
       this.separator, Expression defaultValue) {
     _parameter = becomeParentOf(parameter);
     _defaultValue = becomeParentOf(defaultValue);
   }
 
   @override
   Token get beginToken => _parameter.beginToken;
 
   /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_parameter)
+      ..add(separator)
+      ..add(_defaultValue);
+
+  /**
    * Return the expression computing the default value for the parameter, or `null` if there
    * is no default value.
    *
    * @return the expression computing the default value for the parameter
    */
   Expression get defaultValue => _defaultValue;
 
   /**
    * Set the expression computing the default value for the parameter to the given expression.
    *
@@ skipping 184 matching lines @@
 
   /**
    * Set the body of the loop to the given statement.
    *
    * @param statement the body of the loop
    */
   void set body(Statement statement) {
     _body = becomeParentOf(statement);
   }
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(doKeyword)
+      ..add(_body)
+      ..add(whileKeyword)
+      ..add(leftParenthesis)
+      ..add(_condition)
+      ..add(rightParenthesis)
+      ..add(semicolon);
+
   /**
    * Return the condition that determines when the loop will terminate.
    *
    * @return the condition that determines when the loop will terminate
    */
   Expression get condition => _condition;
 
   /**
    * Set the condition that determines when the loop will terminate to the given expression.
    *
@@ skipping 43 matching lines @@
    * Initialize a newly created floating point literal.
    *
    * @param literal the token representing the literal
    * @param value the value of the literal
    */
   DoubleLiteral(this.literal, this.value);
 
   @override
   Token get beginToken => literal;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(literal);
+
   @override
   Token get endToken => literal;
 
   @override
   accept(AstVisitor visitor) => visitor.visitDoubleLiteral(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     // There are no children to visit.
   }
@@ skipping 177 matching lines @@
   /**
    * Initialize a newly created function body.
    *
    * @param semicolon the token representing the semicolon that marks the end of the function body
    */
   EmptyFunctionBody(this.semicolon);
 
   @override
   Token get beginToken => semicolon;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(semicolon);
+
   @override
   Token get endToken => semicolon;
 
   @override
   accept(AstVisitor visitor) => visitor.visitEmptyFunctionBody(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     // Empty function bodies have no children.
   }
@@ skipping 16 matching lines @@
   /**
    * Initialize a newly created empty statement.
    *
    * @param semicolon the semicolon terminating the statement
    */
   EmptyStatement(this.semicolon);
 
   @override
   Token get beginToken => semicolon;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(semicolon);
+
   @override
   Token get endToken => semicolon;
 
   @override
   accept(AstVisitor visitor) => visitor.visitEmptyStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     // There are no children to visit.
   }
@@ skipping 15 matching lines @@
    * @param comment the documentation comment associated with this declaration
    * @param metadata the annotations associated with this declaration
    * @param name the name of the constant
    */
   EnumConstantDeclaration(Comment comment, List<Annotation> metadata,
       SimpleIdentifier name)
       : super(comment, metadata) {
     _name = becomeParentOf(name);
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => super._childEntities..add(_name);
+
   @override
   FieldElement get element =>
       _name == null ? null : (_name.staticElement as FieldElement);
 
   @override
   Token get endToken => _name.endToken;
 
   @override
   Token get firstTokenAfterCommentAndMetadata => _name.beginToken;
 
@@ skipping 70 matching lines @@
    */
   EnumDeclaration(Comment comment, List<Annotation> metadata, this.keyword,
       SimpleIdentifier name, this.leftBracket,
       List<EnumConstantDeclaration> constants, this.rightBracket)
       : super(comment, metadata) {
     _name = becomeParentOf(name);
     _constants = new NodeList<EnumConstantDeclaration>(this, constants);
   }
 
   /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(keyword)
+      ..add(_name)
+      ..add(leftBracket)
+      ..addAll(_constants)
+      ..add(rightBracket);
+
+  /**
    * Return the enumeration constants being declared.
    *
    * @return the enumeration constants being declared
    */
   NodeList<EnumConstantDeclaration> get constants => _constants;
 
   @override
   ClassElement get element =>
       _name != null ? (_name.staticElement as ClassElement) : null;
 
@@ skipping 57 matching lines @@
    * @param keyword the token representing the 'export' keyword
    * @param libraryUri the URI of the library being exported
    * @param combinators the combinators used to control which names are exported
    * @param semicolon the semicolon terminating the directive
    */
   ExportDirective(Comment comment, List<Annotation> metadata, Token keyword,
       StringLiteral libraryUri, List<Combinator> combinators, Token semicolon)
       : super(comment, metadata, keyword, libraryUri, combinators, semicolon);
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(_uri)
+      ..addAll(combinators)
+      ..add(semicolon);
+
+  @override
   ExportElement get element => super.element as ExportElement;
 
   @override
   LibraryElement get uriElement {
     if (element != null) {
       return element.exportedLibrary;
     }
     return null;
   }
 
@@ skipping 205 matching lines @@
    */
   ExpressionFunctionBody(this.keyword, this.functionDefinition,
       Expression expression, this.semicolon) {
     _expression = becomeParentOf(expression);
   }
 
   @override
   Token get beginToken => functionDefinition;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(functionDefinition)
+      ..add(_expression)
+      ..add(semicolon);
+
+  @override
   Token get endToken {
     if (semicolon != null) {
       return semicolon;
     }
     return _expression.endToken;
   }
 
   /**
    * Return the expression representing the body of the function.
    *
@@ skipping 52 matching lines @@
    * @param semicolon the semicolon terminating the statement
    */
   ExpressionStatement(Expression expression, this.semicolon) {
     _expression = becomeParentOf(expression);
   }
 
   @override
   Token get beginToken => _expression.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_expression)
+      ..add(semicolon);
+
+  @override
   Token get endToken {
     if (semicolon != null) {
       return semicolon;
     }
     return _expression.endToken;
   }
 
   /**
    * Return the expression that comprises the statement.
    *
@@ skipping 49 matching lines @@
    * @param superclass the name of the class that is being extended
    */
   ExtendsClause(this.keyword, TypeName superclass) {
     _superclass = becomeParentOf(superclass);
   }
 
   @override
   Token get beginToken => keyword;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(_superclass);
+
+  @override
   Token get endToken => _superclass.endToken;
 
   /**
    * Return the name of the class that is being extended.
    *
    * @return the name of the class that is being extended
    */
   TypeName get superclass => _superclass;
 
   /**
@@ skipping 48 matching lines @@
    * @param fieldList the fields being declared
    * @param semicolon the semicolon terminating the declaration
    */
   FieldDeclaration(Comment comment, List<Annotation> metadata,
       this.staticKeyword, VariableDeclarationList fieldList, this.semicolon)
       : super(comment, metadata) {
     _fieldList = becomeParentOf(fieldList);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(staticKeyword)
+      ..add(_fieldList)
+      ..add(semicolon);
+
+  @override
   Element get element => null;
 
   @override
   Token get endToken => semicolon;
 
   /**
    * Return the fields being declared.
    *
    * @return the fields being declared
    */
@@ skipping 95 matching lines @@
   Token get beginToken {
     if (keyword != null) {
       return keyword;
     } else if (_type != null) {
       return _type.beginToken;
     }
     return thisToken;
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(keyword)
+      ..add(_type)
+      ..add(thisToken)
+      ..add(period)
+      ..add(identifier)
+      ..add(_parameters);
+
+  @override
   Token get endToken => identifier.endToken;
 
   @override
   bool get isConst =>
       (keyword is KeywordToken) && (keyword as KeywordToken).keyword == Keyword.CONST;
 
   @override
   bool get isFinal =>
       (keyword is KeywordToken) && (keyword as KeywordToken).keyword == Keyword.FINAL;
 
@@ skipping 151 matching lines @@
   /**
    * Set the body of the loop to the given block.
    *
    * @param body the body of the loop
    */
   void set body(Statement body) {
     _body = becomeParentOf(body);
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(awaitKeyword)
+      ..add(forKeyword)
+      ..add(leftParenthesis)
+      ..add(_loopVariable)
+      ..add(_identifier)
+      ..add(inKeyword)
+      ..add(_iterable)
+      ..add(rightParenthesis)
+      ..add(_body);
+
+  @override
   Token get endToken => _body.endToken;
 
   /**
    * Return the loop variable, or `null` if the loop variable is declared in the 'for'.
    *
    * @return the loop variable
    */
   SimpleIdentifier get identifier => _identifier;
 
   /**
@@ skipping 182 matching lines @@
    */
   FormalParameterList(this.leftParenthesis, List<FormalParameter> parameters,
       this.leftDelimiter, this.rightDelimiter, this.rightParenthesis) {
     _parameters = new NodeList<FormalParameter>(this, parameters);
   }
 
   @override
   Token get beginToken => leftParenthesis;
 
   @override
+  Iterable get childEntities {
+    // TODO(paulberry): include commas.
+    ChildEntities result = new ChildEntities()..add(leftParenthesis);
+    bool leftDelimiterNeeded = leftDelimiter != null;
+    for (FormalParameter parameter in _parameters) {
+      if (leftDelimiterNeeded && leftDelimiter.offset < parameter.offset) {
+        result.add(leftDelimiter);
+        leftDelimiterNeeded = false;
+      }
+      result.add(parameter);
+    }
+    return result
+        ..add(rightDelimiter)
+        ..add(rightParenthesis);
+  }
+
+  @override
   Token get endToken => rightParenthesis;
 
   /**
    * Return an array containing the elements representing the parameters in this list. The array
    * will contain `null`s if the parameters in this list have not been resolved.
    *
    * @return the elements representing the parameters in this list
    */
   List<ParameterElement> get parameterElements {
     int count = _parameters.length;
@@ skipping 128 matching lines @@
 
   /**
    * Set the body of the loop to the given statement.
    *
    * @param body the body of the loop
    */
   void set body(Statement body) {
     _body = becomeParentOf(body);
   }
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(forKeyword)
+      ..add(leftParenthesis)
+      ..add(_variableList)
+      ..add(_initialization)
+      ..add(leftSeparator)
+      ..add(_condition)
+      ..add(rightSeparator)
+      ..addAll(_updaters)
+      ..add(rightParenthesis)
+      ..add(_body);
+
   /**
    * Return the condition used to determine when to terminate the loop, or `null` if there is
    * no condition.
    *
    * @return the condition used to determine when to terminate the loop
    */
   Expression get condition => _condition;
 
   /**
    * Set the condition used to determine when to terminate the loop to the given expression.
@@ skipping 162 matching lines @@
   FunctionDeclaration(Comment comment, List<Annotation> metadata,
       this.externalKeyword, TypeName returnType, this.propertyKeyword,
       SimpleIdentifier name, FunctionExpression functionExpression)
       : super(comment, metadata) {
     _returnType = becomeParentOf(returnType);
     _name = becomeParentOf(name);
     _functionExpression = becomeParentOf(functionExpression);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(externalKeyword)
+      ..add(_returnType)
+      ..add(propertyKeyword)
+      ..add(_name)
+      ..add(_functionExpression);
+
+  @override
   ExecutableElement get element =>
       _name != null ? (_name.staticElement as ExecutableElement) : null;
 
   @override
   Token get endToken => _functionExpression.endToken;
 
   @override
   Token get firstTokenAfterCommentAndMetadata {
     if (externalKeyword != null) {
       return externalKeyword;
@@ skipping 101 matching lines @@
    * @param functionDeclaration the the function declaration being wrapped
    */
   FunctionDeclarationStatement(FunctionDeclaration functionDeclaration) {
     _functionDeclaration = becomeParentOf(functionDeclaration);
   }
 
   @override
   Token get beginToken => _functionDeclaration.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()..add(_functionDeclaration);
+
+  @override
   Token get endToken => _functionDeclaration.endToken;
 
   /**
    * Return the function declaration being wrapped.
    *
    * @return the function declaration being wrapped
    */
   FunctionDeclaration get functionDeclaration => _functionDeclaration;
 
   /**
@@ skipping 72 matching lines @@
   /**
    * Set the body of the function to the given function body.
    *
    * @param functionBody the body of the function
    */
   void set body(FunctionBody functionBody) {
     _body = becomeParentOf(functionBody);
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_parameters)
+      ..add(_body);
+
+  @override
   Token get endToken {
     if (_body != null) {
       return _body.endToken;
     } else if (_parameters != null) {
       return _parameters.endToken;
     }
     // This should never be reached because external functions must be named,
     // hence either the body or the name should be non-null.
     throw new IllegalStateException("Non-external functions must have a body");
   }
@@ skipping 101 matching lines @@
    * @return the best element available for this function
    */
   ExecutableElement get bestElement {
     ExecutableElement element = propagatedElement;
     if (element == null) {
       element = staticElement;
     }
     return element;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_function)
+      ..add(_argumentList);
+
   @override
   Token get endToken => _argumentList.endToken;
 
   /**
    * Return the expression producing the function being invoked.
    *
    * @return the expression producing the function being invoked
    */
   Expression get function => _function;
 
@@ skipping 69 matching lines @@
       TypeName returnType, SimpleIdentifier name, TypeParameterList typeParameters,
       FormalParameterList parameters, Token semicolon)
       : super(comment, metadata, keyword, semicolon) {
     _returnType = becomeParentOf(returnType);
     _name = becomeParentOf(name);
     _typeParameters = becomeParentOf(typeParameters);
     _parameters = becomeParentOf(parameters);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(keyword)
+      ..add(_returnType)
+      ..add(_name)
+      ..add(_typeParameters)
+      ..add(_parameters)
+      ..add(semicolon);
+
+  @override
   FunctionTypeAliasElement get element =>
       _name != null ? (_name.staticElement as FunctionTypeAliasElement) : null;
 
   /**
    * Return the name of the function type being declared.
    *
    * @return the name of the function type being declared
    */
   SimpleIdentifier get name => _name;
 
@@ skipping 108 matching lines @@
   }
 
   @override
   Token get beginToken {
     if (_returnType != null) {
       return _returnType.beginToken;
     }
     return identifier.beginToken;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(_returnType)
+      ..add(identifier)
+      ..add(parameters);
+
   @override
   Token get endToken => _parameters.endToken;
 
   @override
   bool get isConst => false;
 
   @override
   bool get isFinal => false;
 
   /**
@@ skipping 492 matching lines @@
    *
    * @param keyword the comma introducing the combinator
    * @param hiddenNames the list of names from the library that are hidden by this combinator
    */
   HideCombinator(Token keyword, List<SimpleIdentifier> hiddenNames)
       : super(keyword) {
     _hiddenNames = new NodeList<SimpleIdentifier>(this, hiddenNames);
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..addAll(_hiddenNames);
+
+  @override
   Token get endToken => _hiddenNames.endToken;
 
   /**
    * Return the list of names from the library that are hidden by this combinator.
    *
    * @return the list of names from the library that are hidden by this combinator
    */
   NodeList<SimpleIdentifier> get hiddenNames => _hiddenNames;
 
   @override
@@ skipping 127 matching lines @@
       this.rightParenthesis, Statement thenStatement, this.elseKeyword,
       Statement elseStatement) {
     _condition = becomeParentOf(condition);
     _thenStatement = becomeParentOf(thenStatement);
     _elseStatement = becomeParentOf(elseStatement);
   }
 
   @override
   Token get beginToken => ifKeyword;
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(ifKeyword)
+      ..add(leftParenthesis)
+      ..add(_condition)
+      ..add(rightParenthesis)
+      ..add(_thenStatement)
+      ..add(elseKeyword)
+      ..add(_elseStatement);
+
   /**
    * Return the condition used to determine which of the statements is executed next.
    *
    * @return the condition used to determine which statement is executed next
    */
   Expression get condition => _condition;
 
   /**
    * Set the condition used to determine which of the statements is executed next to the given
    * expression.
@@ skipping 84 matching lines @@
    * @param keyword the token representing the 'implements' keyword
    * @param interfaces the interfaces that are being implemented
    */
   ImplementsClause(this.keyword, List<TypeName> interfaces) {
     _interfaces = new NodeList<TypeName>(this, interfaces);
   }
 
   @override
   Token get beginToken => keyword;
 
+  /**
+   * TODO(paulberry): add commas.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..addAll(interfaces);
+
   @override
   Token get endToken => _interfaces.endToken;
 
   /**
    * Return the list of the interfaces that are being implemented.
    *
    * @return the list of the interfaces that are being implemented
    */
   NodeList<TypeName> get interfaces => _interfaces;
 
@@ skipping 140 matching lines @@
    * @param semicolon the semicolon terminating the directive
    */
   ImportDirective(Comment comment, List<Annotation> metadata, Token keyword,
       StringLiteral libraryUri, this.deferredToken, this.asToken,
       SimpleIdentifier prefix, List<Combinator> combinators, Token semicolon)
       : super(comment, metadata, keyword, libraryUri, combinators, semicolon) {
     _prefix = becomeParentOf(prefix);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(_uri)
+      ..add(deferredToken)
+      ..add(asToken)
+      ..add(_prefix)
+      ..addAll(combinators)
+      ..add(semicolon);
+
+  @override
   ImportElement get element => super.element as ImportElement;
 
   /**
    * Return the prefix to be used with the imported names, or `null` if the imported names are
    * not prefixed.
    *
    * @return the prefix to be used with the imported names
    */
   SimpleIdentifier get prefix => _prefix;
 
@@ skipping 1217 matching lines @@
    * @return the best element available for this operator
    */
   MethodElement get bestElement {
     MethodElement element = propagatedElement;
     if (element == null) {
       element = staticElement;
     }
     return element;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_target)
+      ..add(period)
+      ..add(leftBracket)
+      ..add(_index)
+      ..add(rightBracket);
+
   @override
   Token get endToken => rightBracket;
 
   /**
    * Return the expression used to compute the index.
    *
    * @return the expression used to compute the index
    */
   Expression get index => _index;
 
@@ skipping 218 matching lines @@
    *
    * @param argumentList the list of arguments to the constructor
    */
   void set argumentList(ArgumentList argumentList) {
     _argumentList = becomeParentOf(argumentList);
   }
 
   @override
   Token get beginToken => keyword;
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(_constructorName)
+      ..add(_argumentList);
+
   /**
    * Return the name of the constructor to be invoked.
    *
    * @return the name of the constructor to be invoked
    */
   ConstructorName get constructorName => _constructorName;
 
   /**
    * Set the name of the constructor to be invoked to the given name.
    *
@@ skipping 58 matching lines @@
    * Initialize a newly created integer literal.
    *
    * @param literal the token representing the literal
    * @param value the value of the literal
    */
   IntegerLiteral(this.literal, this.value);
 
   @override
   Token get beginToken => literal;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(literal);
+
   @override
   Token get endToken => literal;
 
   @override
   accept(AstVisitor visitor) => visitor.visitIntegerLiteral(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     // There are no children to visit.
   }
@@ skipping 48 matching lines @@
    */
   InterpolationExpression(this.leftBracket, Expression expression,
       this.rightBracket) {
     _expression = becomeParentOf(expression);
   }
 
   @override
   Token get beginToken => leftBracket;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(leftBracket)
+      ..add(_expression)
+      ..add(rightBracket);
+
+  @override
   Token get endToken {
     if (rightBracket != null) {
       return rightBracket;
     }
     return _expression.endToken;
   }
 
   /**
    * Return the expression to be evaluated for the value to be converted into a string.
    *
@@ skipping 47 matching lines @@
    * @param value the value of the literal
    */
   InterpolationString(this.contents, String value) {
     _value = value;
   }
 
   @override
   Token get beginToken => contents;
 
   /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(contents);
+
+  /**
    * Return the offset of the after-last contents character.
    */
   int get contentsEnd {
     int end = contents.end;
     String lexeme = contents.lexeme;
     if (StringUtilities.endsWith3(lexeme, 0x22, 0x22, 0x22) ||
         StringUtilities.endsWith3(lexeme, 0x27, 0x27, 0x27)) {
       end -= 3;
     } else {
       end -= 1;
@@ skipping 86 matching lines @@
   IsExpression(Expression expression, this.isOperator, this.notOperator,
       TypeName type) {
     _expression = becomeParentOf(expression);
     _type = becomeParentOf(type);
   }
 
   @override
   Token get beginToken => _expression.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_expression)
+      ..add(isOperator)
+      ..add(notOperator)
+      ..add(_type);
+
+  @override
   Token get endToken => _type.endToken;
 
   /**
    * Return the expression used to compute the value whose type is being tested.
    *
    * @return the expression used to compute the value whose type is being tested
    */
   Expression get expression => _expression;
 
   /**
@@ skipping 60 matching lines @@
    * @param label the label being applied
    * @param colon the colon that separates the label from whatever follows
    */
   Label(SimpleIdentifier label, this.colon) {
     _label = becomeParentOf(label);
   }
 
   @override
   Token get beginToken => _label.beginToken;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_label)
+      ..add(colon);
+
   @override
   Token get endToken => colon;
 
   /**
    * Return the label being associated with the statement.
    *
    * @return the label being associated with the statement
    */
   SimpleIdentifier get label => _label;
 
@@ skipping 47 matching lines @@
   }
 
   @override
   Token get beginToken {
     if (!_labels.isEmpty) {
       return _labels.beginToken;
     }
     return _statement.beginToken;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..addAll(_labels)
+      ..add(_statement);
+
   @override
   Token get endToken => _statement.endToken;
 
   /**
    * Return the labels being associated with the statement.
    *
    * @return the labels being associated with the statement
    */
   NodeList<Label> get labels => _labels;
 
@@ skipping 59 matching lines @@
    * @param name the name of the library being defined
    * @param semicolon the semicolon terminating the directive
    */
   LibraryDirective(Comment comment, List<Annotation> metadata,
       this.libraryToken, LibraryIdentifier name, this.semicolon)
       : super(comment, metadata) {
     _name = becomeParentOf(name);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(libraryToken)
+      ..add(_name)
+      ..add(semicolon);
+
+  @override
   Token get endToken => semicolon;
 
   @override
   Token get firstTokenAfterCommentAndMetadata => libraryToken;
 
   @override
   Token get keyword => libraryToken;
 
   /**
    * Return the name of the library being defined.
@@ skipping 44 matching lines @@
     _components = new NodeList<SimpleIdentifier>(this, components);
   }
 
   @override
   Token get beginToken => _components.beginToken;
 
   @override
   Element get bestElement => staticElement;
 
   /**
+   * TODO(paulberry): add "." tokens.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..addAll(_components);
+
+  /**
    * Return the components of the identifier.
    *
    * @return the components of the identifier
    */
   NodeList<SimpleIdentifier> get components => _components;
 
   @override
   Token get endToken => _components.endToken;
 
   @override
@@ skipping 75 matching lines @@
       return constKeyword;
     }
     TypeArgumentList typeArguments = this.typeArguments;
     if (typeArguments != null) {
       return typeArguments.beginToken;
     }
     return leftBracket;
   }
 
   /**
+   * TODO(paulberry): add commas.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(leftBracket)
+      ..addAll(_elements)
+      ..add(rightBracket);
+
+  /**
    * Return the expressions used to compute the elements of the list.
    *
    * @return the expressions used to compute the elements of the list
    */
   NodeList<Expression> get elements => _elements;
 
   @override
   Token get endToken => rightBracket;
 
   @override
@@ skipping 71 matching lines @@
     if (constKeyword != null) {
       return constKeyword;
     }
     TypeArgumentList typeArguments = this.typeArguments;
     if (typeArguments != null) {
       return typeArguments.beginToken;
     }
     return leftBracket;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   * TODO(paulberry): add commas.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(leftBracket)
+      ..addAll(entries)
+      ..add(rightBracket);
+
   @override
   Token get endToken => rightBracket;
 
   /**
    * Return the entries in the map.
    *
    * @return the entries in the map
    */
   NodeList<MapLiteralEntry> get entries => _entries;
 
@@ skipping 40 matching lines @@
    * @param value the expression computing the value that will be associated with the key
    */
   MapLiteralEntry(Expression key, this.separator, Expression value) {
     _key = becomeParentOf(key);
     _value = becomeParentOf(value);
   }
 
   @override
   Token get beginToken => _key.beginToken;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_key)
+      ..add(separator)
+      ..add(_value);
+
   @override
   Token get endToken => _value.endToken;
 
   /**
    * Return the expression computing the key with which the value will be associated.
    *
    * @return the expression computing the key with which the value will be associated
    */
   Expression get key => _key;
 
@@ skipping 129 matching lines @@
 
   /**
    * Set the body of the method to the given function body.
    *
    * @param functionBody the body of the method
    */
   void set body(FunctionBody functionBody) {
     _body = becomeParentOf(functionBody);
   }
 
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(externalKeyword)
+      ..add(modifierKeyword)
+      ..add(_returnType)
+      ..add(propertyKeyword)
+      ..add(operatorKeyword)
+      ..add(_name)
+      ..add(_parameters)
+      ..add(_body);
+
   /**
    * Return the element associated with this method, or `null` if the AST structure has not
    * been resolved. The element can either be a [MethodElement], if this represents the
    * declaration of a normal method, or a [PropertyAccessorElement] if this represents the
    * declaration of either a getter or a setter.
    *
    * @return the element associated with this method
    */
   @override
   ExecutableElement get element =>
@@ skipping 190 matching lines @@
   Token get beginToken {
     if (_target != null) {
       return _target.beginToken;
     } else if (period != null) {
       return period;
     }
     return _methodName.beginToken;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_target)
+      ..add(period)
+      ..add(_methodName)
+      ..add(_argumentList);
+
+  @override
   Token get endToken => _argumentList.endToken;
 
   /**
    * Return `true` if this expression is cascaded. If it is, then the target of this
    * expression is not stored locally but is stored in the nearest ancestor that is a
    * [CascadeExpression].
    *
    * @return `true` if this expression is cascaded
    */
   bool get isCascaded =>
@@ skipping 98 matching lines @@
    * @param expression the expression with which the name is associated
    */
   NamedExpression(Label name, Expression expression) {
     _name = becomeParentOf(name);
     _expression = becomeParentOf(expression);
   }
 
   @override
   Token get beginToken => _name.beginToken;
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_name)
+      ..add(_expression);
+
   /**
    * Return the element representing the parameter being named by this expression, or `null`
    * if the AST structure has not been resolved or if there is no parameter with the same name as
    * this expression.
    *
    * @return the element representing the parameter being named by this expression
    */
   ParameterElement get element {
     Element element = _name.label.staticElement;
     if (element is ParameterElement) {
@@ skipping 135 matching lines @@
    * @param keyword the token representing the 'native' keyword
    * @param name the name of the native object that implements the class.
    */
   NativeClause(this.keyword, StringLiteral name) {
     _name = becomeParentOf(name);
   }
 
   @override
   Token get beginToken => keyword;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(_name);
+
   @override
   Token get endToken => _name.endToken;
 
   /**
    * Return the name of the native object that implements the class.
    *
    * @return the name of the native object that implements the class
    */
   StringLiteral get name => _name;
 
@@ skipping 49 matching lines @@
    * @param semicolon the token representing the semicolon that marks the end of the function body
    */
   NativeFunctionBody(this.nativeToken, StringLiteral stringLiteral,
       this.semicolon) {
     _stringLiteral = becomeParentOf(stringLiteral);
   }
 
   @override
   Token get beginToken => nativeToken;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(nativeToken)
+      ..add(_stringLiteral)
+      ..add(semicolon);
+
   @override
   Token get endToken => semicolon;
 
   /**
    * Return the string literal representing the string after the 'native' token.
    *
    * @return the string literal representing the string after the 'native' token
    */
   StringLiteral get stringLiteral => _stringLiteral;
 
@@ skipping 1518 matching lines @@
    * @return the comment and annotations associated with this parameter in the order in which they
    *         appeared in the original source
    */
   List<AstNode> get sortedCommentAndAnnotations {
     return <AstNode>[]
         ..add(_comment)
         ..addAll(_metadata)
         ..sort(AstNode.LEXICAL_ORDER);
   }
 
+  ChildEntities get _childEntities {
+    ChildEntities result = new ChildEntities();
+    if (_commentIsBeforeAnnotations()) {
+      result
+          ..add(_comment)
+          ..addAll(_metadata);
+    } else {
+      result.addAll(sortedCommentAndAnnotations);
+    }
+    return result;
+  }
+
   @override
   void visitChildren(AstVisitor visitor) {
     //
     // Note that subclasses are responsible for visiting the identifier because
     // they often need to visit other nodes before visiting the identifier.
     //
     if (_commentIsBeforeAnnotations()) {
       safelyVisitChild(_comment, visitor);
       _metadata.accept(visitor);
     } else {
@@ skipping 34 matching lines @@
   /**
    * Initialize a newly created null literal.
    *
    * @param token the token representing the literal
    */
   NullLiteral(this.literal);
 
   @override
   Token get beginToken => literal;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(literal);
+
   @override
   Token get endToken => literal;
 
   @override
   accept(AstVisitor visitor) => visitor.visitNullLiteral(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     // There are no children to visit.
   }
@@ skipping 32 matching lines @@
    */
   ParenthesizedExpression(this.leftParenthesis, Expression expression,
       this.rightParenthesis) {
     _expression = becomeParentOf(expression);
   }
 
   @override
   Token get beginToken => leftParenthesis;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(leftParenthesis)
+      ..add(_expression)
+      ..add(rightParenthesis);
+
+  @override
   Token get endToken => rightParenthesis;
 
   /**
    * Return the expression within the parentheses.
    *
    * @return the expression within the parentheses
    */
   Expression get expression => _expression;
 
   /**
@@ skipping 42 matching lines @@
    * @param comment the documentation comment associated with this directive
    * @param metadata the annotations associated with the directive
    * @param partToken the token representing the 'part' token
    * @param partUri the URI of the part being included
    * @param semicolon the semicolon terminating the directive
    */
   PartDirective(Comment comment, List<Annotation> metadata, this.partToken,
       StringLiteral partUri, this.semicolon)
       : super(comment, metadata, partUri);
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(partToken)
+      ..add(_uri)
+      ..add(semicolon);
+
   @override
   Token get endToken => semicolon;
 
   @override
   Token get firstTokenAfterCommentAndMetadata => partToken;
 
   @override
   Token get keyword => partToken;
 
   @override
@@ skipping 42 matching lines @@
    * @param libraryName the name of the library that the containing compilation unit is part of
    * @param semicolon the semicolon terminating the directive
    */
   PartOfDirective(Comment comment, List<Annotation> metadata, this.partToken,
       this.ofToken, LibraryIdentifier libraryName, this.semicolon)
       : super(comment, metadata) {
     _libraryName = becomeParentOf(libraryName);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(partToken)
+      ..add(ofToken)
+      ..add(_libraryName)
+      ..add(semicolon);
+
+  @override
   Token get endToken => semicolon;
 
   @override
   Token get firstTokenAfterCommentAndMetadata => partToken;
 
   @override
   Token get keyword => partToken;
 
   /**
    * Return the name of the library that the containing compilation unit is part of.
@@ skipping 76 matching lines @@
    * @return the best element available for this operator
    */
   MethodElement get bestElement {
     MethodElement element = propagatedElement;
     if (element == null) {
       element = staticElement;
     }
     return element;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_operand)
+      ..add(operator);
+
   @override
   Token get endToken => operator;
 
   /**
    * Return the expression computing the operand for the operator.
    *
    * @return the expression computing the operand for the operator
    */
   Expression get operand => _operand;
 
@@ skipping 104 matching lines @@
 
   @override
   Element get bestElement {
     if (_identifier == null) {
       return null;
     }
     return _identifier.bestElement;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_prefix)
+      ..add(period)
+      ..add(_identifier);
+
+  @override
   Token get endToken => _identifier.endToken;
 
   /**
    * Return the identifier being prefixed.
    *
    * @return the identifier being prefixed
    */
   SimpleIdentifier get identifier => _identifier;
 
   /**
@@ skipping 132 matching lines @@
    */
   MethodElement get bestElement {
     MethodElement element = propagatedElement;
     if (element == null) {
       element = staticElement;
     }
     return element;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(operator)
+      ..add(_operand);
+
+  @override
   Token get endToken => _operand.endToken;
 
   /**
    * Return the expression computing the operand for the operator.
    *
    * @return the expression computing the operand for the operator
    */
   Expression get operand => _operand;
 
   /**
@@ skipping 102 matching lines @@
 
   @override
   Token get beginToken {
     if (_target != null) {
       return _target.beginToken;
     }
     return operator;
   }
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_target)
+      ..add(operator)
+      ..add(_propertyName);
+
+  @override
   Token get endToken => _propertyName.endToken;
 
   @override
   bool get isAssignable => true;
 
   /**
    * Return `true` if this expression is cascaded. If it is, then the target of this
    * expression is not stored locally but is stored in the nearest ancestor that is a
    * [CascadeExpression].
    *
@@ skipping 786 matching lines @@
    *
    * @param argumentList the list of arguments to the constructor
    */
   void set argumentList(ArgumentList argumentList) {
     _argumentList = becomeParentOf(argumentList);
   }
 
   @override
   Token get beginToken => keyword;
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(period)
+      ..add(_constructorName)
+      ..add(_argumentList);
+
   /**
    * Return the name of the constructor that is being invoked, or `null` if the unnamed
    * constructor is being invoked.
    *
    * @return the name of the constructor that is being invoked
    */
   SimpleIdentifier get constructorName => _constructorName;
 
   /**
    * Set the name of the constructor that is being invoked to the given identifier.
@@ skipping 35 matching lines @@
   /**
    * Initialize a newly created rethrow expression.
    *
    * @param keyword the token representing the 'rethrow' keyword
    */
   RethrowExpression(this.keyword);
 
   @override
   Token get beginToken => keyword;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(keyword);
+
   @override
   Token get endToken => keyword;
 
   @override
   int get precedence => 0;
 
   @override
   accept(AstVisitor visitor) => visitor.visitRethrowExpression(this);
 
   @override
@@ skipping 35 matching lines @@
    * @param semicolon the semicolon terminating the statement
    */
   ReturnStatement(this.keyword, Expression expression, this.semicolon) {
     _expression = becomeParentOf(expression);
   }
 
   @override
   Token get beginToken => keyword;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(_expression)
+      ..add(semicolon);
+
+  @override
   Token get endToken => semicolon;
 
   /**
    * Return the expression computing the value to be returned, or `null` if no explicit value
    * was provided.
    *
    * @return the expression computing the value to be returned
    */
   Expression get expression => _expression;
 
@@ skipping 218 matching lines @@
   /**
    * Initialize a newly created script tag.
    *
    * @param scriptTag the token representing this script tag
    */
   ScriptTag(this.scriptTag);
 
   @override
   Token get beginToken => scriptTag;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(scriptTag);
+
   @override
   Token get endToken => scriptTag;
 
   @override
   accept(AstVisitor visitor) => visitor.visitScriptTag(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     // There are no children to visit.
   }
@@ skipping 18 matching lines @@
    * Initialize a newly created import show combinator.
    *
    * @param keyword the comma introducing the combinator
    * @param shownNames the list of names from the library that are made visible by this combinator
    */
   ShowCombinator(Token keyword, List<SimpleIdentifier> shownNames)
       : super(keyword) {
     _shownNames = new NodeList<SimpleIdentifier>(this, shownNames);
   }
 
+  /**
+   * TODO(paulberry): add commas.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..addAll(_shownNames);
+
   @override
   Token get endToken => _shownNames.endToken;
 
   /**
    * Return the list of names from the library that are made visible by this combinator.
    *
    * @return the list of names from the library that are made visible by this combinator
    */
   NodeList<SimpleIdentifier> get shownNames => _shownNames;
 
@@ skipping 380 matching lines @@
     if (!metadata.isEmpty) {
       return metadata.beginToken;
     } else if (keyword != null) {
       return keyword;
     } else if (_type != null) {
       return _type.beginToken;
     }
     return identifier.beginToken;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(keyword)
+      ..add(_type)
+      ..add(identifier);
+
   @override
   Token get endToken => identifier.endToken;
 
   @override
   bool get isConst =>
       (keyword is KeywordToken) && (keyword as KeywordToken).keyword == Keyword.CONST;
 
   @override
   bool get isFinal =>
       (keyword is KeywordToken) && (keyword as KeywordToken).keyword == Keyword.FINAL;
@@ skipping 75 matching lines @@
   Token get beginToken => token;
 
   @override
   Element get bestElement {
     if (_propagatedElement == null) {
       return _staticElement;
     }
     return _propagatedElement;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(token);
+
   @override
   Token get endToken => token;
 
   /**
    * Returns `true` if this identifier is the "name" part of a prefixed identifier or a method
    * invocation.
    *
    * @return `true` if this identifier is the "name" part of a prefixed identifier or a method
    *         invocation
    */
@@ skipping 318 matching lines @@
    * @param value the value of the literal
    */
   SimpleStringLiteral(this.literal, String value) {
     _value = StringUtilities.intern(value);
   }
 
   @override
   Token get beginToken => literal;
 
   @override
+  Iterable get childEntities => new ChildEntities()..add(literal);
+
+  @override
   int get contentsEnd {
     return contentsOffset + value.length;
   }
 
   @override
   int get contentsOffset {
     int contentsOffset = 0;
     if (isRaw) {
       contentsOffset += 1;
     }
@@ skipping 162 matching lines @@
    * @param elements the elements that will be composed to produce the resulting string
    */
   StringInterpolation(List<InterpolationElement> elements) {
     _elements = new NodeList<InterpolationElement>(this, elements);
   }
 
   @override
   Token get beginToken => _elements.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()..addAll(_elements);
+
+  @override
   int get contentsEnd {
     InterpolationString element = _elements.last;
     return element.contentsEnd;
   }
 
   @override
   int get contentsOffset {
     InterpolationString element = _elements.first;
     return element.contentsOffset;
   }
@@ skipping 30 matching lines @@
   }
 
   @override
   accept(AstVisitor visitor) => visitor.visitStringInterpolation(this);
 
   @override
   void appendStringValue(StringBuffer buffer) {
     throw new IllegalArgumentException();
   }
 
-
   @override
   void visitChildren(AstVisitor visitor) {
     _elements.accept(visitor);
   }
 }
 
 /**
  * Instances of the class `StringLiteral` represent a string literal expression.
  *
  * <pre>
@@ skipping 91 matching lines @@
    *
    * @param argumentList the list of arguments to the constructor
    */
   void set argumentList(ArgumentList argumentList) {
     _argumentList = becomeParentOf(argumentList);
   }
 
   @override
   Token get beginToken => keyword;
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(period)
+      ..add(_constructorName)
+      ..add(_argumentList);
+
   /**
    * Return the name of the constructor that is being invoked, or `null` if the unnamed
    * constructor is being invoked.
    *
    * @return the name of the constructor that is being invoked
    */
   SimpleIdentifier get constructorName => _constructorName;
 
   /**
    * Set the name of the constructor that is being invoked to the given identifier.
@@ skipping 34 matching lines @@
   /**
    * Initialize a newly created super expression.
    *
    * @param keyword the token representing the keyword
    */
   SuperExpression(this.keyword);
 
   @override
   Token get beginToken => keyword;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(keyword);
+
   @override
   Token get endToken => keyword;
 
   @override
   int get precedence => 16;
 
   @override
   accept(AstVisitor visitor) => visitor.visitSuperExpression(this);
 
   @override
@@ skipping 24 matching lines @@
    * @param expression the expression controlling whether the statements will be executed
    * @param colon the colon separating the keyword or the expression from the statements
    * @param statements the statements that will be executed if this switch member is selected
    */
   SwitchCase(List<Label> labels, Token keyword, Expression expression,
       Token colon, List<Statement> statements)
       : super(labels, keyword, colon, statements) {
     _expression = becomeParentOf(expression);
   }
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..addAll(labels)
+      ..add(keyword)
+      ..add(_expression)
+      ..add(colon)
+      ..addAll(statements);
+
   /**
    * Return the expression controlling whether the statements will be executed.
    *
    * @return the expression controlling whether the statements will be executed
    */
   Expression get expression => _expression;
 
   /**
    * Set the expression controlling whether the statements will be executed to the given expression.
    *
@@ skipping 28 matching lines @@
    *
    * @param labels the labels associated with the switch member
    * @param keyword the token representing the 'case' or 'default' keyword
    * @param colon the colon separating the keyword or the expression from the statements
    * @param statements the statements that will be executed if this switch member is selected
    */
   SwitchDefault(List<Label> labels, Token keyword, Token colon,
       List<Statement> statements)
       : super(labels, keyword, colon, statements);
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..addAll(labels)
+      ..add(keyword)
+      ..add(colon)
+      ..addAll(statements);
+
   @override
   accept(AstVisitor visitor) => visitor.visitSwitchDefault(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     labels.accept(visitor);
     statements.accept(visitor);
   }
 }
 
@@ skipping 132 matching lines @@
       this.rightParenthesis, this.leftBracket, List<SwitchMember> members,
       this.rightBracket) {
     _expression = becomeParentOf(expression);
     _members = new NodeList<SwitchMember>(this, members);
   }
 
   @override
   Token get beginToken => keyword;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(leftParenthesis)
+      ..add(_expression)
+      ..add(rightParenthesis)
+      ..add(leftBracket)
+      ..addAll(_members)
+      ..add(rightBracket);
+
+  @override
   Token get endToken => rightBracket;
 
   /**
    * Return the expression used to determine which of the switch members will be selected.
    *
    * @return the expression used to determine which of the switch members will be selected
    */
   Expression get expression => _expression;
 
   /**
@@ skipping 46 matching lines @@
    * Initialize a newly created symbol literal.
    *
    * @param poundSign the token introducing the literal
    * @param components the components of the literal
    */
   SymbolLiteral(this.poundSign, this.components);
 
   @override
   Token get beginToken => poundSign;
 
+  /**
+   * TODO(paulberry): untested.
+   * TODO(paulberry): add "." tokens.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(poundSign)
+      ..addAll(components);
+
   @override
   Token get endToken => components[components.length - 1];
 
   @override
   accept(AstVisitor visitor) => visitor.visitSymbolLiteral(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     // There are no children to visit.
   }
@@ skipping 16 matching lines @@
   /**
    * Initialize a newly created this expression.
    *
    * @param keyword the token representing the keyword
    */
   ThisExpression(this.keyword);
 
   @override
   Token get beginToken => keyword;
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()..add(keyword);
+
   @override
   Token get endToken => keyword;
 
   @override
   int get precedence => 16;
 
   @override
   accept(AstVisitor visitor) => visitor.visitThisExpression(this);
 
   @override
@@ skipping 28 matching lines @@
    * @param expression the expression computing the exception to be thrown
    */
   ThrowExpression(this.keyword, Expression expression) {
     _expression = becomeParentOf(expression);
   }
 
   @override
   Token get beginToken => keyword;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(_expression);
+
+  @override
   Token get endToken {
     if (_expression != null) {
       return _expression.endToken;
     }
     return keyword;
   }
 
   /**
    * Return the expression computing the exception to be thrown.
    *
@@ skipping 51 matching lines @@
    * @param variableList the top-level variables being declared
    * @param semicolon the semicolon terminating the declaration
    */
   TopLevelVariableDeclaration(Comment comment, List<Annotation> metadata,
       VariableDeclarationList variableList, this.semicolon)
       : super(comment, metadata) {
     _variableList = becomeParentOf(variableList);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(_variableList)
+      ..add(semicolon);
+
+  @override
   Element get element => null;
 
   @override
   Token get endToken => semicolon;
 
   @override
   Token get firstTokenAfterCommentAndMetadata => _variableList.beginToken;
 
   /**
    * Return the top-level variables being declared.
@@ skipping 1229 matching lines @@
   }
 
   /**
    * Return the catch clauses contained in the try statement.
    *
    * @return the catch clauses contained in the try statement
    */
   NodeList<CatchClause> get catchClauses => _catchClauses;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(tryKeyword)
+      ..add(_body)
+      ..addAll(_catchClauses)
+      ..add(finallyKeyword)
+      ..add(_finallyBlock);
+
+  @override
   Token get endToken {
     if (_finallyBlock != null) {
       return _finallyBlock.endToken;
     } else if (finallyKeyword != null) {
       return finallyKeyword;
     } else if (!_catchClauses.isEmpty) {
       return _catchClauses.endToken;
     }
     return _body.endToken;
   }
@@ skipping 107 matching lines @@
   /**
    * Return the type arguments associated with the type.
    *
    * @return the type arguments associated with the type
    */
   NodeList<TypeName> get arguments => _arguments;
 
   @override
   Token get beginToken => leftBracket;
 
+  /**
+   * TODO(paulberry): Add commas.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(leftBracket)
+      ..addAll(_arguments)
+      ..add(rightBracket);
+
   @override
   Token get endToken => rightBracket;
 
   @override
   accept(AstVisitor visitor) => visitor.visitTypeArgumentList(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _arguments.accept(visitor);
   }
@@ skipping 42 matching lines @@
 
   /**
    * Set the type argument associated with this literal to the given arguments.
    *
    * @param typeArguments the type argument associated with this literal
    */
   void set typeArguments(TypeArgumentList typeArguments) {
     _typeArguments = becomeParentOf(typeArguments);
   }
 
+  ChildEntities get _childEntities => new ChildEntities()
+      ..add(constKeyword)
+      ..add(_typeArguments);
+
   @override
   void visitChildren(AstVisitor visitor) {
     safelyVisitChild(_typeArguments, visitor);
   }
 }
 
 /**
  * Instances of the class `TypeName` represent the name of a type, which can optionally
  * include type arguments.
  *
@@ skipping 27 matching lines @@
    */
   TypeName(Identifier name, TypeArgumentList typeArguments) {
     _name = becomeParentOf(name);
     _typeArguments = becomeParentOf(typeArguments);
   }
 
   @override
   Token get beginToken => _name.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_name)
+      ..add(_typeArguments);
+
+  @override
   Token get endToken {
     if (_typeArguments != null) {
       return _typeArguments.endToken;
     }
     return _name.endToken;
   }
 
   /**
    * Return `true` if this type is a deferred type.
    *
@@ skipping 109 matching lines @@
   /**
    * Set the name of the upper bound for legal arguments to the given type name.
    *
    * @param typeName the name of the upper bound for legal arguments
    */
   void set bound(TypeName typeName) {
     _bound = becomeParentOf(typeName);
   }
 
   @override
+  Iterable get childEntities => super._childEntities
+      ..add(_name)
+      ..add(keyword)
+      ..add(_bound);
+
+  @override
   TypeParameterElement get element =>
       _name != null ? (_name.staticElement as TypeParameterElement) : null;
 
   @override
   Token get endToken {
     if (_bound == null) {
       return _name.endToken;
     }
     return _bound.endToken;
   }
@@ skipping 61 matching lines @@
    */
   TypeParameterList(this.leftBracket, List<TypeParameter> typeParameters,
       this.rightBracket) {
     _typeParameters = new NodeList<TypeParameter>(this, typeParameters);
   }
 
   @override
   Token get beginToken => leftBracket;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(leftBracket)
+      ..addAll(_typeParameters)
+      ..add(rightBracket);
+
+  @override
   Token get endToken => rightBracket;
 
   /**
    * Return the type parameters for the type.
    *
    * @return the type parameters for the type
    */
   NodeList<TypeParameter> get typeParameters => _typeParameters;
 
   @override
@@ skipping 520 matching lines @@
    * @param equals the equal sign separating the variable name from the initial value
    * @param initializer the expression used to compute the initial value for the variable
    */
   VariableDeclaration(Comment comment, List<Annotation> metadata,
       SimpleIdentifier name, this.equals, Expression initializer)
       : super(comment, metadata) {
     _name = becomeParentOf(name);
     _initializer = becomeParentOf(initializer);
   }
 
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(_name)
+      ..add(equals)
+      ..add(_initializer);
+
   /**
    * This overridden implementation of getDocumentationComment() looks in the grandparent node for
    * dartdoc comments if no documentation is specifically available on the node.
    */
   @override
   Comment get documentationComment {
     Comment comment = super.documentationComment;
     if (comment == null) {
       if (parent != null && parent.parent != null) {
         AstNode node = parent.parent;
@@ skipping 127 matching lines @@
    * @param type the type of the variables being declared
    * @param variables a list containing the individual variables being declared
    */
   VariableDeclarationList(Comment comment, List<Annotation> metadata,
       this.keyword, TypeName type, List<VariableDeclaration> variables)
       : super(comment, metadata) {
     _type = becomeParentOf(type);
     _variables = new NodeList<VariableDeclaration>(this, variables);
   }
 
+  /**
+   * TODO(paulberry): include commas.
+   */
+  @override
+  Iterable get childEntities => super._childEntities
+      ..add(keyword)
+      ..add(_type)
+      ..addAll(_variables);
+
   @override
   Token get endToken => _variables.endToken;
 
   @override
   Token get firstTokenAfterCommentAndMetadata {
     if (keyword != null) {
       return keyword;
     } else if (_type != null) {
       return _type.beginToken;
     }
@@ skipping 80 matching lines @@
    */
   VariableDeclarationStatement(VariableDeclarationList variableList,
       this.semicolon) {
     _variableList = becomeParentOf(variableList);
   }
 
   @override
   Token get beginToken => _variableList.beginToken;
 
   @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(_variableList)
+      ..add(semicolon);
+
+  @override
   Token get endToken => semicolon;
 
   /**
    * Return the variables being declared.
    *
    * @return the variables being declared
    */
   VariableDeclarationList get variables => _variableList;
 
   /**
@@ skipping 75 matching lines @@
 
   /**
    * Set the body of the loop to the given statement.
    *
    * @param statement the body of the loop
    */
   void set body(Statement statement) {
     _body = becomeParentOf(statement);
   }
 
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(keyword)
+      ..add(leftParenthesis)
+      ..add(_condition)
+      ..add(rightParenthesis)
+      ..add(_body);
+
   /**
    * Return the expression used to determine whether to execute the body of the loop.
    *
    * @return the expression used to determine whether to execute the body of the loop
    */
   Expression get condition => _condition;
 
   /**
    * Set the expression used to determine whether to execute the body of the loop to the given
    * expression.
@@ skipping 42 matching lines @@
    * @param withKeyword the token representing the 'with' keyword
    * @param mixinTypes the names of the mixins that were specified
    */
   WithClause(this.withKeyword, List<TypeName> mixinTypes) {
     _mixinTypes = new NodeList<TypeName>(this, mixinTypes);
   }
 
   @override
   Token get beginToken => withKeyword;
 
+  /**
+   * TODO(paulberry): add commas.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(withKeyword)
+      ..addAll(_mixinTypes);
+
   @override
   Token get endToken => _mixinTypes.endToken;
 
   /**
    * Set the token representing the 'with' keyword to the given token.
    *
    * @param withKeyword the token representing the 'with' keyword
    */
   @deprecated
   void set mixinKeyword(Token withKeyword) {
@@ skipping 54 matching lines @@
   }
 
   @override
   Token get beginToken {
     if (yieldKeyword != null) {
       return yieldKeyword;
     }
     return _expression.beginToken;
   }
 
+  /**
+   * TODO(paulberry): untested.
+   */
+  @override
+  Iterable get childEntities => new ChildEntities()
+      ..add(yieldKeyword)
+      ..add(star)
+      ..add(_expression)
+      ..add(semicolon);
+
   @override
   Token get endToken {
     if (semicolon != null) {
       return semicolon;
     }
     return _expression.endToken;
   }
 
   /**
    * Return the expression whose value will be yielded.
@@ skipping 12 matching lines @@
   }
 
   @override
   accept(AstVisitor visitor) => visitor.visitYieldStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     safelyVisitChild(_expression, visitor);
   }
 }