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

tests/language/function_type_alias_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.
 // VMOptions=--enable_type_checks
 //
 // Dart test for function type alias.
 
 typedef Fun(a, b);
 
 typedef int IntFun(a, b);
@@ skipping 50 matching lines @@
     int compareStrLenReverse(String a, String b, [bool reverse = false]) {
       return reverse ? (a.length - b.length) : (b.length - a.length);
     }
     Expect.isTrue(compareStrLenReverse is Fun);
     Expect.isTrue(compareStrLenReverse is IntFun);
     Expect.isTrue(compareStrLenReverse is !BoolFun);
     Expect.isTrue(compareStrLenReverse is CompareObj);
     Expect.isTrue(compareStrLenReverse is !CompareInt);
     Expect.isTrue(compareStrLenReverse is CompareString);
 
-    int compareObj(Object a, Object b) { return a === b ? 0 : -1; }
+    int compareObj(Object a, Object b) { return identical(a, b) ? 0 : -1; }
     Expect.isTrue(compareObj is Fun);
     Expect.isTrue(compareObj is IntFun);
     Expect.isTrue(compareObj is !BoolFun);
     Expect.isTrue(compareObj is CompareObj);
     Expect.isTrue(compareObj is CompareInt);
     Expect.isTrue(compareObj is !CompareString);
     Expect.equals(-1, test(compareObj, "abcdef", "xyz"));
 
     CompareInt minus = int _(int a, int b) { return a - b; };
     Expect.isTrue(minus is Fun);
@@ skipping 17 matching lines @@
     Function boundsTrue = void _(int arg) { };
     Function boundsFalse = void _(String arg) { };
     Expect.isTrue(boundsTrue is BoundsCheck<num>);
     Expect.isFalse(boundsFalse is BoundsCheck<num>);
   }
 }
 
 main() {
   FunctionTypeAliasTest.testMain();
 }