anchor.diff:      safelyVisitChildren(fields, visitor);
     }
   
  -  /**
  -   * Return an iterable containing all of the implementations of a getter with
  -   * the given [getterName] that are defined in this class any any superclass of
  -   * this class (but not in interfaces).
  -   *
  -   * The getters that are returned are not filtered in any way. In particular,
  -   * they can include getters that are not visible in some context. Clients must
  -   * perform any necessary filtering.
  -   *
  -   * The getters are returned based on the depth of their defining class; if
  -   * this class contains a definition of the getter it will occur first, if
  -   * Object contains a definition of the getter it will occur last.
  -   */
  +  /// Return an iterable containing all of the implementations of a getter with
  +  /// the given [getterName] that are defined in this class any any superclass
  +  /// of this class (but not in interfaces).
  +  ///
  +  /// The getters that are returned are not filtered in any way. In particular,
  +  /// they can include getters that are not visible in some context. Clients
  +  /// must perform any necessary filtering.
  +  ///
  +  /// The getters are returned based on the depth of their defining class; if
  +  /// this class contains a definition of the getter it will occur first, if
  +  /// Object contains a definition of the getter it will occur last.
     Iterable<PropertyAccessorElement> _implementationsOfGetter(
         String getterName) sync* {
       ClassElement classElement = this;
  
positive.code:   }
  }
  
  /**
   * An abstract constant field of an enum.
   */
  abstract class ConstFieldElementImpl_ofEnum extends ConstFieldElementImpl {
    final EnumElementImpl _enum;
  
  
negative.code:   @override
    String get documentationComment => _docComment;
  
    /// The documentation comment source for this element.
    void set documentationComment(String doc) {
      assert(!isResynthesized);
      _docComment = doc?.replaceAll('\r\n', '\n');
  