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 000000000..c19e15c17
--- /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: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ */
+/* 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::RootedGlobalObject g(cx, cx->global());
+    JS::Rooted<js::LexicalEnvironmentObject*> env(
+        cx, js::LexicalEnvironmentObject::createGlobal(cx, g));
+
+    JS::RootedValue uninitialized(cx, JS::MagicValue(JS_UNINITIALIZED_LEXICAL));
+    js::RootedPropertyName name(cx, Atomize(cx, "foopi", 4)->asPropertyName());
+    JS::RootedId id(cx, NameToId(name));
+    unsigned attrs = JSPROP_ENUMERATE | JSPROP_PERMANENT;
+
+    CHECK(NativeDefineProperty(cx, env, id, uninitialized, nullptr, nullptr, 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)