anchor.diff:      // There are no children to visit
     }
   
  -  /**
  -   * Return annotations for the given [unlinkedConsts] in the [unit].
  -   */
  +  /// Return annotations for the given [unlinkedConsts] in the [unit].
     List<ElementAnnotation> _buildAnnotations(
         CompilationUnitElementImpl unit, List<UnlinkedExpr> unlinkedConsts) {
       int length = unlinkedConsts.length;
  
positive.code:   }
  }
  
  /**
   * Mixin representing an element which can have type parameters.
   */
  abstract class TypeParameterizedElementMixin
      implements TypeParameterizedElement, ElementImpl {
    /**
     * A cached list containing the type parameters declared by this element
     * directly, or `null` if the elements have not been created yet. This does
     * not include type parameters that are declared by any enclosing elements.
     */
    List<TypeParameterElement> _typeParameterElements;
  
    /**
     * A cached list containing the type parameter types declared by this element
     * directly, or `null` if the list has not been computed yet.
     */
    List<TypeParameterType> _typeParameterTypes;
  
    /**
     * Get the type parameter context enclosing this one, if any.
     */
    TypeParameterizedElementMixin get enclosingTypeParameterContext;
  
    @override
  
negative.code:   T accept<T>(ElementVisitor<T> visitor) => null;
  }
  
  /// A concrete implementation of an [ElementAnnotation].
  class ElementAnnotationImpl implements ElementAnnotation {
    /// The name of the top-level variable used to mark that a function always
    /// throws, for dead code purposes.
    static String _ALWAYS_THROWS_VARIABLE_NAME = "alwaysThrows";
  
    /// The name of the top-level variable used to mark a method parameter as
    /// covariant.
    static String _COVARIANT_VARIABLE_NAME = "checked";
  
    /// The name of the class used to mark an element as being deprecated.
    static String _DEPRECATED_CLASS_NAME = "Deprecated";
  
    /// The name of the top-level variable used to mark an element as being
    /// deprecated.
    static String _DEPRECATED_VARIABLE_NAME = "deprecated";
  
    /// The name of the top-level variable used to mark a method as being a
    /// factory.
    static String _FACTORY_VARIABLE_NAME = "factory";
  
    /// The name of the top-level variable used to mark a class and its subclasses
    /// as being immutable.
    static String _IMMUTABLE_VARIABLE_NAME = "immutable";
  
    /// The name of the top-level variable used to mark a function as running
    /// a single test.
    static String _IS_TEST_VARIABLE_NAME = "isTest";
  
    /// The name of the top-level variable used to mark a function as running
    /// a test group.
    static String _IS_TEST_GROUP_VARIABLE_NAME = "isTestGroup";
  
    /// The name of the class used to JS annotate an element.
    static String _JS_CLASS_NAME = "JS";
  
    /// The name of `js` library, used to define JS annotations.
    static String _JS_LIB_NAME = "js";
  
    /// The name of `meta` library, used to define analysis annotations.
    static String _META_LIB_NAME = "meta";
  
    /// The name of the top-level variable used to mark a method as requiring
    /// overriders to call super.
    static String _MUST_CALL_SUPER_VARIABLE_NAME = "mustCallSuper";
  
    /// The name of `angular.meta` library, used to define angular analysis
    /// annotations.
    static String _NG_META_LIB_NAME = "angular.meta";
  
    /// The name of the top-level variable used to mark a method as being expected
    /// to override an inherited method.
    static String _OVERRIDE_VARIABLE_NAME = "override";
  
    /// The name of the top-level variable used to mark a method as being
    /// protected.
    static String _PROTECTED_VARIABLE_NAME = "protected";
  
    /// The name of the top-level variable used to mark a class as implementing a
    /// proxy object.
    static String PROXY_VARIABLE_NAME = "proxy";
  
    /// The name of the class used to mark a parameter as being required.
    static String _REQUIRED_CLASS_NAME = "Required";
  
    /// The name of the top-level variable used to mark a parameter as being
    /// required.
    static String _REQUIRED_VARIABLE_NAME = "required";
  
    /// The name of the top-level variable used to mark a class as being sealed.
    static String _SEALED_VARIABLE_NAME = "sealed";
  
    /// The name of the top-level variable used to mark a method as being
  