1 files changed, 54 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Proxy/set/trap-is-undefined-target-is-proxy.js b/js/src/tests/test262/built-ins/Proxy/set/trap-is-undefined-target-is-proxy.js
new file mode 100644
index 0000000000..ac2f7a8497
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Proxy/set/trap-is-undefined-target-is-proxy.js
@@ -0,0 +1,54 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-proxy-object-internal-methods-and-internal-slots-set-p-v-receiver
+description: >
+  If "set" trap is null or undefined, [[Set]] call is properly
+  forwarded to [[ProxyTarget]] (which is also a Proxy object).
+info: |
+  [[Set]] ( P, V, Receiver )
+
+  [...]
+  5. Let target be O.[[ProxyTarget]].
+  6. Let trap be ? GetMethod(handler, "set").
+  7. If trap is undefined, then
+    a. Return ? target.[[Set]](P, V, Receiver).
+features: [Proxy, Reflect]
+---*/
+
+var func = function() {};
+var funcTarget = new Proxy(func, {});
+var funcProxy = new Proxy(funcTarget, {
+  set: undefined,
+});
+
+assert(Reflect.set(funcProxy, "prototype", null));
+assert.sameValue(func.prototype, null);
+
+assert(!Reflect.set(funcProxy, "length", 2));
+assert.throws(TypeError, function() {
+  "use strict";
+  funcProxy.name = "foo";
+});
+
+
+var trapCalls = 0;
+var target = new Proxy({}, {
+  set: function(_target, key) {
+    trapCalls++;
+    return key === "foo";
+  },
+});
+
+var proxy = new Proxy(target, {
+  set: undefined,
+});
+
+assert(Reflect.set(Object.create(proxy), "foo", 1));
+assert.sameValue(trapCalls, 1);
+
+assert(!Reflect.set(proxy, "bar", 2));
+assert.sameValue(trapCalls, 2);
+
+reportCompare(0, 0);