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

tests/standalone/io/stream_pipe_test.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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 #import("dart:io");
@@ skipping 99 matching lines @@
         };
 
         socketInput.pipe(fileOutput);
       };
 
       fileInput.pipe(socketOutput);
     }
 
     // Connect to the server.
     _socket = new Socket(TestingServer.HOST, _port);
-    if (_socket !== null) {
+    if (_socket != null) {
       _socket.onConnect = connectHandler;
     } else {
       Expect.fail("socket creation failed");
     }
   }
 
   void initialize() {
     _receivePort.receive((var message, SendPort replyTo) {
       _port = message;
       runTest();
@@ skipping 154 matching lines @@
   srcStream.pipe(dstStream, close: false);
 }
 
 
 main() {
   testFileToFilePipe1();
   testFileToFilePipe2();
   testFileToFilePipe3();
   PipeServerGame echoServerGame = new PipeServerGame.start();
 }