a === b -> identical(a, b)

sdk/lib/mirrors/mirrors.dart

 // Copyright (c) 2012, 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.
 
 // The dart:mirrors library provides reflective access for Dart program.
 //
 // For the purposes of the mirrors library, we adopt a naming
 // convention with respect to getters and setters.  Specifically, for
 // some variable or field...
 //
@@ skipping 136 matching lines @@
    * Is this declaration private?
    *
    * Note that for libraries, this will be [:false:].
    */
   bool get isPrivate;
 
   /**
    * Is this declaration top-level?
    *
    * This is defined to be equivalent to:
-   *    [:mirror.owner !== null && mirror.owner is LibraryMirror:]
+   *    [:mirror.owner != null && mirror.owner is LibraryMirror:]
    */
   bool get isTopLevel;
 
   /**
    * The source location of this Dart language entity.
    */
   SourceLocation get location;
 }
 
 /**
@@ skipping 568 matching lines @@
 
 /**
  * A [MirrorException] is used to indicate errors within the mirrors
  * framework.
  */
 class MirrorException implements Exception {
   const MirrorException(String this._message);
   String toString() => "MirrorException: '$_message'";
   final String _message;
 }