1 files changed, 39 insertions, 0 deletions
diff --git a/js/src/jsapi-tests/testForceLexicalInitialization.cpp b/js/src/jsapi-tests/testForceLexicalInitialization.cpp
new file mode 100644
index 0000000000..be0468897d
--- /dev/null
+++ b/js/src/jsapi-tests/testForceLexicalInitialization.cpp
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ */
+/* 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/. */
+
+#include "jsfriendapi.h"
+#include "jsapi-tests/tests.h"
+#include "vm/EnvironmentObject.h"
+
+BEGIN_TEST(testForceLexicalInitialization) {
+  // Attach an uninitialized lexical to a scope and ensure that it's
+  // set to undefined
+  JS::Rooted<js::GlobalObject*> g(cx, cx->global());
+  JS::Rooted<js::GlobalLexicalEnvironmentObject*> env(
+      cx, js::GlobalLexicalEnvironmentObject::create(cx, g));
+
+  JS::RootedValue uninitialized(cx, JS::MagicValue(JS_UNINITIALIZED_LEXICAL));
+  JS::Rooted<js::PropertyName*> name(cx,
+                                     Atomize(cx, "foopi", 4)->asPropertyName());
+  JS::RootedId id(cx, NameToId(name));
+  unsigned attrs = JSPROP_ENUMERATE | JSPROP_PERMANENT;
+
+  CHECK(NativeDefineDataProperty(cx, env, id, uninitialized, attrs));
+
+  // Verify that "foopi" is uninitialized
+  const JS::Value v = env->getSlot(env->lookup(cx, id)->slot());
+  CHECK(v.isMagic(JS_UNINITIALIZED_LEXICAL));
+
+  ForceLexicalInitialization(cx, env);
+
+  // Verify that "foopi" has been initialized to undefined
+  const JS::Value v2 = env->getSlot(env->lookup(cx, id)->slot());
+  CHECK(v2.isUndefined());
+
+  return true;
+}
+END_TEST(testForceLexicalInitialization)