anchor.diff:  
     /// Returns the members defined by the class/mixin.
     NodeList<ClassMember> get members;
  -
  -  @override
  -  SimpleIdentifier get name;
   
     /// Returns the right curly bracket.
     Token get rightBracket;
  
positive.code:   /// Return the native clause for this class, or `null` if the class does not
    /// have a native clause.
    NativeClause? get nativeClause;
  
    /// Return the with clause for the class, or `null` if the class does not have
    /// a with clause.
    WithClause? get withClause;
  
    /// Return the constructor declared in the class with the given [name], or
    /// `null` if there is no such constructor.
  
negative.code: /// Clients may not extend, implement or mix-in this class.
  abstract class ClassMember implements Declaration {}
  
  /// Shared interface between [ClassDeclaration] and
  /// [ClassAugmentationDeclaration].
  ///
  /// Clients may not extend, implement or mix-in this class.
  @experimental
  abstract class ClassOrAugmentationDeclaration
      implements NamedCompilationUnitMember {
    /// Return the 'abstract' keyword, or `null` if the keyword was absent.
    ///
    /// In valid code only [ClassDeclaration] can specify it.
    Token? get abstractKeyword;
  
    /// Returns the token representing the 'class' keyword.
    Token get classKeyword;
  
    /// Returns the `extends` clause for this class, or `null` if the class
    /// does not extend any other class.
    ///
    /// In valid code only [ClassDeclaration] can specify it.
    ExtendsClause? get extendsClause;
  
    /// Returns the `implements` clause for the class, or `null` if the class
    /// does not implement any interfaces.
    ImplementsClause? get implementsClause;
  
    /// Returns the left curly bracket.
    Token get leftBracket;
  
    /// Returns the members defined by the class.
    NodeList<ClassMember> get members;
  
    /// Returns the right curly bracket.
    Token get rightBracket;
  
    /// Returns the type parameters for the class, or `null` if the class does
    /// not have any type parameters.
    TypeParameterList? get typeParameters;
  
    /// Returns the `with` clause for the class, or `null` if the class does not
    /// have a `with` clause.
    WithClause? get withClause;
  }
  
  /// The declaration of a class or mixin.
  ///
  /// Clients may not extend, implement or mix-in this class.
  // TODO(scheglov) Deprecate and remove.
  abstract class ClassOrMixinDeclaration implements NamedCompilationUnitMember {
    @override
    ClassElement? get declaredElement;
  