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

utils/template/parser.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 
 class TagStack {
   List<ASTNode> _stack;
 
   TagStack(var elem) : _stack = [] {
     _stack.add(elem);
   }
 
@@ skipping 134 matching lines @@
     var message;
     try {
       message = 'expected $expected, but found $tok';
     } catch (e) {
       message = 'parsing error expected $expected';
     }
     _error(message, tok.span);
   }
 
   void _error(String message, [SourceSpan location=null]) {
-    if (location === null) {
+    if (location == null) {
       location = _peekToken.span;
     }
 
     if (printHandler == null) {
       world.fatal(message, location);    // syntax errors are fatal for now
     } else {
       // TODO(terry):  Need common World view for css and template parser.
       //               For now this is how we return errors from CSS - ugh.
       printHandler(message);
     }
   }
 
   void _warning(String message, [SourceSpan location=null]) {
-    if (location === null) {
+    if (location == null) {
       location = _peekToken.span;
     }
 
     if (printHandler == null) {
       world.warning(message, location);
     } else {
       // TODO(terry):  Need common World view for css and template parser.
       //               For now this is how we return errors from CSS - ugh.
       printHandler(message);
     }
@@ skipping 531 matching lines @@
     }
 
     if (stringValue.length > 0) {
       nodes.add(new TemplateText(stringValue.toString(), _makeSpan(start)));
     }
 
     return nodes;
   }
 
 }