Validation of `@mustCallSuper` overrides.

pkg/analyzer/lib/src/dart/element/element.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.src.dart.element.element;
 
 import 'dart:collection';
 import 'dart:math' show min;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 1583 matching lines @@
    * deprecated.
    */
   static String _DEPRECATED_VARIABLE_NAME = "deprecated";
 
   /**
    * 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 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";
@@ skipping 46 matching lines @@
       if (element is ConstructorElement) {
         return element.enclosingElement.name == _DEPRECATED_CLASS_NAME;
       } else if (element is PropertyAccessorElement) {
         return element.name == _DEPRECATED_VARIABLE_NAME;
       }
     }
     return false;
   }
 
   @override
+  bool get isMustCallSuper =>
+      element is PropertyAccessorElement &&
+      element.name == _MUST_CALL_SUPER_VARIABLE_NAME &&
+      element.library?.name == _META_LIB_NAME;
+
+  @override
   bool get isOverride =>
       element is PropertyAccessorElement &&
       element.name == _OVERRIDE_VARIABLE_NAME &&
       element.library?.isDartCore == true;
 
   @override
   bool get isProtected =>
       element is PropertyAccessorElement &&
       element.name == _PROTECTED_VARIABLE_NAME &&
       element.library?.name == _META_LIB_NAME;
@@ skipping 3218 matching lines @@
 
   @override
   void visitElement(Element element) {
     int offset = element.nameOffset;
     if (offset != -1) {
       map[offset] = element;
     }
     super.visitElement(element);
   }
 }