Re-apply "What if you closurize identical?" but this time don't be magic: it requires the compiler …

tests/language/identical_closure_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.
 
 var myIdentical = identical;
 
 class Point {
   num x, y;
   Point(this.x, this.y);
 }
 
 main() {
-  // Smi.
+  // int.
   Expect.isTrue(myIdentical(42, 42));
   Expect.isFalse(myIdentical(42, 41));
 
-  // Double.
+  // double.
   Expect.isTrue(myIdentical(42.0, 42.0));
   Expect.isFalse(myIdentical(42.0, 41.0));
 
   // Mint (2^45).
   Expect.isTrue(myIdentical(35184372088832,35184372088832));
   Expect.isFalse(myIdentical(35184372088832,35184372088831));
 
-  // Bigint (2^76).
-  Expect.isTrue(myIdentical(75557863725914323419136,
-                            75557863725914323419136));
-  Expect.isFalse(myIdentical(75557863725914323419136,
-                             75557863725914323419137));
-
   // Different types.
-  Expect.isFalse(myIdentical(42, 42.0));
   Expect.isFalse(myIdentical("hello", 41));
 
   // Points.
   var p = new Point(1,1);
   var q = new Point(1,1);
   Expect.isFalse(myIdentical(p, q));
 
   // Strings.
   var a = "hello";
   var b = "hello";
   // Identical strings are coalesced into single instances.
   Expect.isTrue(myIdentical(a, b));
 
-  // Null and NaN handling.
+  // Null handling.
   Expect.isFalse(myIdentical(42, null));
   Expect.isTrue(myIdentical(null, null));
-  Expect.isTrue(myIdentical(double.NAN, double.NAN));
-}
+}