Support ES6's "new function" construct

This resolves #75.

Merged remote-tracking branch 'janek/js_function_new_1'

1 files changed, 79 insertions, 0 deletions

diff --git a/js/src/tests/ecma_6/Generators/construct-newtarget.js b/js/src/tests/ecma_6/Generators/construct-newtarget.js
new file mode 100644
index 000000000..f2087852b
--- /dev/null
+++ b/js/src/tests/ecma_6/Generators/construct-newtarget.js
@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const GeneratorFunction = function*(){}.constructor;
+
+
+// Test subclassing %GeneratorFunction% works correctly.
+class MyGenerator extends GeneratorFunction {}
+
+var fn = new MyGenerator();
+assertEq(fn instanceof MyGenerator, true);
+assertEq(fn instanceof GeneratorFunction, true);
+assertEq(Object.getPrototypeOf(fn), MyGenerator.prototype);
+
+fn = Reflect.construct(MyGenerator, []);
+assertEq(fn instanceof MyGenerator, true);
+assertEq(fn instanceof GeneratorFunction, true);
+assertEq(Object.getPrototypeOf(fn), MyGenerator.prototype);
+
+fn = Reflect.construct(MyGenerator, [], MyGenerator);
+assertEq(fn instanceof MyGenerator, true);
+assertEq(fn instanceof GeneratorFunction, true);
+assertEq(Object.getPrototypeOf(fn), MyGenerator.prototype);
+
+fn = Reflect.construct(MyGenerator, [], GeneratorFunction);
+assertEq(fn instanceof MyGenerator, false);
+assertEq(fn instanceof GeneratorFunction, true);
+assertEq(Object.getPrototypeOf(fn), GeneratorFunction.prototype);
+
+
+// Set a different constructor as NewTarget.
+fn = Reflect.construct(MyGenerator, [], Array);
+assertEq(fn instanceof MyGenerator, false);
+assertEq(fn instanceof GeneratorFunction, false);
+assertEq(Object.getPrototypeOf(fn), Array.prototype);
+
+fn = Reflect.construct(GeneratorFunction, [], Array);
+assertEq(fn instanceof GeneratorFunction, false);
+assertEq(Object.getPrototypeOf(fn), Array.prototype);
+
+
+// The prototype defaults to %GeneratorFunctionPrototype% if null.
+function NewTargetNullPrototype() {}
+NewTargetNullPrototype.prototype = null;
+
+fn = Reflect.construct(GeneratorFunction, [], NewTargetNullPrototype);
+assertEq(fn instanceof GeneratorFunction, true);
+assertEq(Object.getPrototypeOf(fn), GeneratorFunction.prototype);
+
+fn = Reflect.construct(MyGenerator, [], NewTargetNullPrototype);
+assertEq(fn instanceof MyGenerator, false);
+assertEq(fn instanceof GeneratorFunction, true);
+assertEq(Object.getPrototypeOf(fn), GeneratorFunction.prototype);
+
+
+// "prototype" property is retrieved exactly once.
+var trapLog = [], getLog = [];
+var ProxiedConstructor = new Proxy(GeneratorFunction, new Proxy({
+    get(target, propertyKey, receiver) {
+        getLog.push(propertyKey);
+        return Reflect.get(target, propertyKey, receiver);
+    }
+}, {
+    get(target, propertyKey, receiver) {
+        trapLog.push(propertyKey);
+        return Reflect.get(target, propertyKey, receiver);
+    }
+}));
+
+fn = Reflect.construct(GeneratorFunction, [], ProxiedConstructor);
+assertEqArray(trapLog, ["get"]);
+assertEqArray(getLog, ["prototype"]);
+assertEq(fn instanceof GeneratorFunction, true);
+assertEq(Object.getPrototypeOf(fn), GeneratorFunction.prototype);
+
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);