Make identical(a,b) a compile-time constant in dart2js.

lib/compiler/implementation/compiler.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.
 
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
 const bool REPORT_EXCESS_RESOLUTION = false;
@@ skipping 104 matching lines @@
   ClassElement dynamicClass;
   ClassElement boolClass;
   ClassElement numClass;
   ClassElement intClass;
   ClassElement doubleClass;
   ClassElement stringClass;
   ClassElement functionClass;
   ClassElement nullClass;
   ClassElement listClass;
   Element assertMethod;
+  Element identicalFunction;
 
   Element get currentElement => _currentElement;
   withCurrentElement(Element element, f()) {
     Element old = currentElement;
     _currentElement = element;
     try {
       return f();
     } on CompilerCancelledException catch (ex) {
       throw;
     } on StackOverflowException catch (ex) {
@@ skipping 225 matching lines @@
     jsHelperLibrary = scanBuiltinLibrary('_js_helper');
     interceptorsLibrary = scanBuiltinLibrary('_interceptors');
 
     addForeignFunctions(jsHelperLibrary);
     addForeignFunctions(interceptorsLibrary);
 
     libraries['dart:core'] = coreLibrary;
     libraries['dart:coreimpl'] = coreImplLibrary;
 
     assertMethod = jsHelperLibrary.find(const SourceString('assert'));
+    identicalFunction = coreLibrary.find(const SourceString('identical'));

[ahe, 2012/09/18 08:30:17]

This doesn't report an error if it cannot find 'identical'. Same problem for
'assert'. So you forgot to update dart/tests/utils/dummy_compiler_test.dart, and
possibly other tests.

Perhaps we should report errors here.

 
     initializeSpecialClasses();
   }
 
   void importCoreLibrary(LibraryElement library) {
     Uri coreUri = new Uri.fromComponents(scheme: 'dart', path: 'core');
     if (coreLibrary === null) {
       coreLibrary = scanner.loadLibrary(coreUri, null, coreUri);
     }
     scanner.importLibrary(library,
@@ skipping 559 matching lines @@
     final endOffset = end.charOffset + end.slowCharCount;
 
     // [begin] and [end] might be the same for the same empty token. This
     // happens for instance when scanning '$$'.
     assert(endOffset >= beginOffset);
     return f(beginOffset, endOffset);
   }
 
   String toString() => 'SourceSpan($uri, $begin, $end)';
 }