Classes: Fix issue with default constructor crash

test/mjsunit/harmony/classes.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --harmony
 
 (function TestBasics() {
   var C = class C {}
   assertEquals(typeof C, 'function');
   assertEquals(C.__proto__, Function.prototype);
   assertEquals(Object.prototype, Object.getPrototypeOf(C.prototype));
   assertEquals(Function.prototype, Object.getPrototypeOf(C));
   assertEquals('C', C.name);
 
   class D {}
   assertEquals(typeof D, 'function');
   assertEquals(D.__proto__, Function.prototype);
   assertEquals(Object.prototype, Object.getPrototypeOf(D.prototype));
   assertEquals(Function.prototype, Object.getPrototypeOf(D));
   assertEquals('D', D.name);
 
+  class D2 { constructor() {} }
+  assertEquals('D2', D2.name);
+
+  class D3 {}
+  class D4 {}
+  assertEquals('D3', D3.name);
+  assertEquals('D4', D4.name);
+
+  // TODO(arv): The logic for the name of anonymous functions in ES6 requires
+  // the below to be 'E';
   var E = class {}
-  assertEquals('', E.name);
+  assertEquals('', E.name);  // Should be 'E'.
+
+  var F = class { constructor() {} };
+  assertEquals('', F.name);  // Should be 'F'.
 })();
 
 
 (function TestBasicsExtends() {
   class C extends null {}
   assertEquals(typeof C, 'function');
   assertEquals(C.__proto__, Function.prototype);
   assertEquals(null, Object.getPrototypeOf(C.prototype));
 
   class D extends C {}
@@ skipping 548 matching lines @@
     static get 5() { return super[5]; }
   }
 
   assertEquals(1, new C()[1]());
   assertEquals(2, new C()[2]);
   assertEquals(4, C[4]());
   assertEquals(5, C[5]);
 })();
 
 
+(function TestDefaultConstructorNoCrash() {
+  // Regression test for https://code.google.com/p/v8/issues/detail?id=3661
+  class C {}
+  assertEquals(undefined, C());
+  assertEquals(undefined, C(1));
+  assertTrue(new C() instanceof C);
+  assertTrue(new C(1) instanceof C);
+})();
+
+
+(function TestDefaultConstructor() {
+  var calls = 0;
+  class Base {
+    constructor() {
+      calls++;
+    }
+  }
+  class Derived extends Base {}
+  var object = new Derived;
+  assertEquals(1, calls);
+
+  calls = 0;
+  Derived();
+  assertEquals(1, calls);
+})();
+
+
 /* TODO(arv): Implement
 (function TestNameBindingInConstructor() {
   class C {
     constructor() {
       assertThrows(function() {
         C = 42;
       }, ReferenceError);
     }
   }
   new C();
 })();
 */