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

tests/language/list_literal3_test.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
 // BSD-style license that can be found in the LICENSE file.
 // Check that arrays from const array literals are immutable.
 
 class ListLiteral3Test {
 
   static const List<String> canonicalJoke = const ["knock", "knock"];
 
   static testMain() {
 
     List<String> joke = const ["knock", "knock"];
     // Elements of canonical lists are canonicalized.
-    Expect.equals(true, joke === canonicalJoke);
-    Expect.equals(true, joke[0] === joke[1]);
-    Expect.equals(true, joke[0] === canonicalJoke[0]);
+    Expect.equals(true, identical(joke, canonicalJoke));
+    Expect.equals(true, identical(joke[0], joke[1]));
+    Expect.equals(true, identical(joke[0], canonicalJoke[0]));
 
     // Lists from literals are immutable.
     bool caughtException = false;
     try {

[Lasse Reichstein Nielsen, 2012/11/12 13:10:41]

use: 
 Expect.throws(()=>joke[0] = "sock", (e) => e is UnspoortedError);

[floitsch, 2012/11/12 22:18:43]

Done.

       joke[0] = "sock";
     } on UnsupportedError catch (e) {
       caughtException = true;
     }
     Expect.equals(true, caughtException);
-    Expect.equals(true, joke[0] === joke[1]);
+    Expect.equals(true, identical(joke[0], joke[1]));
 
     // Make sure lists allocated at runtime are mutable and are
     // not canonicalized.
     List<String> lame_joke = ["knock", "knock"];  // Invokes operator new.
-    Expect.equals(true, joke[1] === lame_joke[1]);
+    Expect.equals(true, identical(joke[1], lame_joke[1]));
     // Operator new creates a mutable list.
-    Expect.equals(false, joke === lame_joke);
+    Expect.equals(false, identical(joke, lame_joke));
     lame_joke[1] = "who";
-    Expect.equals(true, "who" === lame_joke[1]);
+    Expect.equals(true, identical("who", lame_joke[1]));
 
     // Elements of canonical lists are canonicalized.
     List<List<int>> a = const <List<int>>[ const [1, 2], const [1, 2]];
-    Expect.equals(true, a[0] === a[1]);
-    Expect.equals(true, a[0][0] === a[1][0]);
+    Expect.equals(true, identical(a[0], a[1]));

[Lasse Reichstein Nielsen, 2012/11/12 13:10:41]

Expect.identical

[floitsch, 2012/11/12 22:18:43]

Done.

+    Expect.equals(true, identical(a[0][0], a[1][0]));
     try {
       caughtException = false;
       a[0][0] = 42;
     } on UnsupportedError catch (e) {
       caughtException = true;
     }
     Expect.equals(true, caughtException);
 
     List<List<double>> b = const [ const [1.0, 2.0], const [1.0, 2.0]];
-    Expect.equals(true, b[0] === b[1]);
-    Expect.equals(true, b[0][0] === 1.0);
-    Expect.equals(true, b[0][0] === b[1][0]);
+    Expect.equals(true, identical(b[0], b[1]));
+    Expect.equals(true, b[0][0] == 1.0);
+    Expect.equals(true, identical(b[0][0], b[1][0]));
     try {
       caughtException = false;
       b[0][0] = 42.0;
     } on UnsupportedError catch (e) {
       caughtException = true;
     }
     Expect.equals(true, caughtException);
   }
 }
 
 main() {
   ListLiteral3Test.testMain();
 }