new classes: special construct stub for derived classs and TDZ for `this`.

test/mjsunit/harmony/classes-experimental.js

Index: test/mjsunit/harmony/classes-experimental.js
diff --git a/test/mjsunit/harmony/classes-experimental.js b/test/mjsunit/harmony/classes-experimental.js
index 73944b182c607d82801e224c44d9e4c8bb288cf6..1a0f872e79e22eba318ba6a73d5c1605d01b80a7 100644
--- a/test/mjsunit/harmony/classes-experimental.js
+++ b/test/mjsunit/harmony/classes-experimental.js
@@ -7,29 +7,34 @@
 'use strict';
 
 class Base {
-  constructor() {
+  constructor(a, b) {
     let o = new Object();
-    o.prp = 1;
+    o.prp = a + b;
     return o;
   }
 }
 
 class Subclass extends Base {
-  constructor() {
+  constructor(a, b) {
+    var exn;
     try {
       this.prp1 = 3;
     } catch (e) {
-      // TODO(dslomov): actually test the exception once TDZ is implemented.
+      exn = e;
     }
-    super();
-    assertSame(1, this.prp);
+    assertTrue(exn instanceof ReferenceError);
+    super(a, b);
+    assertSame(a + b, this.prp);
     assertSame(undefined, this.prp1);
     assertFalse(this.hasOwnProperty("prp1"));
     return this;

[arv (Not doing code reviews), 2015/01/24 16:19:09]

Can you add a few more test cases?

1. A constructor without `return this`.
2. A constructor with a second call to `super()` which should throw.

[Dmitry Lomov (no reviews), 2015/01/26 23:34:04]

This is not implemented yet - coming next
Done, actually required code changes.

   }
 }
 
-let s = new Subclass();
+let b = new Base(1, 2);
+assertSame(3, b.prp);
+
+let s = new Subclass(2, -1);
 assertSame(1, s.prp);
 assertSame(undefined, s.prp1);
 assertFalse(s.hasOwnProperty("prp1"));