1 files changed, 20 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/proxy/testDirectProxySet9.js b/js/src/jit-test/tests/proxy/testDirectProxySet9.js
new file mode 100644
index 0000000000..7a08b3c0cd
--- /dev/null
+++ b/js/src/jit-test/tests/proxy/testDirectProxySet9.js
@@ -0,0 +1,20 @@
+// Assigning to a proxy with no set handler calls the defineProperty handler
+// when an existing own data property already exists on the target.
+
+var t = {x: 1};
+var p = new Proxy(t, {
+    defineProperty(t, id, desc) {
+        hits++;
+
+        // ES6 draft rev 28 (2014 Oct 14) 9.1.9 step 5.e.i.
+        // Since the property already exists, the system only changes
+        // the value. desc is otherwise empty.
+        assertEq(Object.getOwnPropertyNames(desc).join(","), "value");
+        assertEq(desc.value, 42);
+        return true;
+    }
+});
+var hits = 0;
+p.x = 42;
+assertEq(hits, 1);
+assertEq(t.x, 1);