1 files changed, 31 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/for-of/semantics-10.js b/js/src/jit-test/tests/for-of/semantics-10.js
new file mode 100644
index 0000000000..03f6bc3cfc
--- /dev/null
+++ b/js/src/jit-test/tests/for-of/semantics-10.js
@@ -0,0 +1,31 @@
+// The LHS of a for-loop is not bound to a particular scope until after the .next() method returns.
+
+var obj = {};
+
+// Test 1
+function* g() {
+    obj.x = 0;
+    yield 1;
+}
+var x = 2, n = 0;
+with (obj) {
+    for (x of g())  // g().next() inserts a binding for x on obj
+        n++;
+}
+assertEq(x, 2);
+assertEq(obj.x, 1);
+assertEq(n, 1);
+
+// Test 2
+function* h() {
+    delete obj.x;
+    yield 3;
+}
+n = 0;
+with (obj) {
+    for (x of h())  // h().next() deletes the binding for x on obj
+        n++;
+}
+assertEq(x, 3);
+assertEq("x" in obj, false);
+assertEq(n, 1);