1 files changed, 61 insertions, 0 deletions
diff --git a/js/src/tests/non262/Proxy/proxy-proto-lazy-props.js b/js/src/tests/non262/Proxy/proxy-proto-lazy-props.js
new file mode 100644
index 0000000000..c82c0f935b
--- /dev/null
+++ b/js/src/tests/non262/Proxy/proxy-proto-lazy-props.js
@@ -0,0 +1,61 @@
+function makeProxyPrototype(target) {
+    return Object.setPrototypeOf(target, new Proxy({}, new Proxy({
+        getPrototypeOf() {
+            return null;
+        },
+        ownKeys() {
+            return [];
+        },
+        get(t, pk, r) {
+            throw new Error("Unexpected [[Get]]: " + String(pk));
+        }
+    }, {
+        get(t, pk, r) {
+            if (pk in t)
+                return Reflect.get(t, pk, r);
+            throw new Error("Unexpected trap called: " + pk);
+        }
+    })));
+}
+
+function enumerateMappedArgs(x) {
+    var a = makeProxyPrototype(arguments);
+
+    // Delete all lazy properties and ensure no [[Has]] trap is called for them
+    // on the prototype chain.
+    delete a.length;
+    delete a.callee;
+    delete a[Symbol.iterator];
+    delete a[0];
+
+    for (var k in a);
+}
+enumerateMappedArgs(0);
+
+function enumerateUnmappedArgs(x) {
+    "use strict";
+    var a = makeProxyPrototype(arguments);
+
+    delete a.length;
+    // delete a.callee; // .callee is non-configurable
+    delete a[Symbol.iterator];
+    delete a[0];
+
+    for (var k in a);
+}
+enumerateUnmappedArgs(0);
+
+function enumerateFunction() {
+    var f = makeProxyPrototype(function named() {});
+
+    // delete f.prototype; // .prototype is non-configurable
+    delete f.length;
+    delete f.name;
+
+    for (var k in f);
+}
+enumerateFunction();
+
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);