From 833fed7a72a34ffca6583356e4a6b3d4a5db25f2 Mon Sep 17 00:00:00 2001
From: Caio Lima <caiolima@igalia.com>
Date: Wed, 18 Mar 2026 12:29:29 -0300
Subject: [PATCH 1/2] Adding case for super access of a module namespace TDZ
 binding

---
 .../internals/super-access-to-tdz-binding.js  | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 test/language/module-code/namespace/internals/super-access-to-tdz-binding.js

diff --git a/test/language/module-code/namespace/internals/super-access-to-tdz-binding.js b/test/language/module-code/namespace/internals/super-access-to-tdz-binding.js
new file mode 100644
index 00000000000..5e1876eba3d
--- /dev/null
+++ b/test/language/module-code/namespace/internals/super-access-to-tdz-binding.js
@@ -0,0 +1,46 @@
+// Copyright (C) 2026 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-module-namespace-exotic-objects-getownproperty-p
+description: >
+    super.foo = V throws ReferenceError when Receiver is a module namespace
+    with an uninitialized binding
+info: |
+    OrdinarySetWithOwnDescriptor ( _O_, _P_, _V_, _Receiver_, _ownDesc_ )
+      ...
+      1. If IsDataDescriptor(_ownDesc_) is *true*, then
+        1. If _ownDesc_.[[Writable]] is *false*, return *false*.
+        1. If _Receiver_ is not an Object, return *false*.
+        1. Let _existingDescriptor_ be ? _Receiver_.[[GetOwnProperty]](_P_).
+        ...
+
+    [[GetOwnProperty]] ( _P_ )
+      ...
+      1. Let _value_ be ? _O_.[[Get]](_P_, _O_).
+      ...
+
+    [[Get]] ( _P_, _Receiver_ )
+      ...
+      1. Let _targetEnvRec_ be _targetEnv_'s EnvironmentRecord.
+      1. Return ? _targetEnvRec_.GetBindingValue(_binding_.[[BindingName]], *true*).
+
+    NOTE: If the binding is uninitialized, GetBindingValue throws a *ReferenceError*.
+flags: [module]
+features: [let]
+---*/
+
+import * as ns from './super-access-to-tdz-binding.js';
+
+class A { constructor() { return ns; } };
+class B extends A {
+  constructor() {
+    super();
+    super.foo = 14;
+  }
+};
+
+assert.throws(ReferenceError, function() {
+  new B();
+});
+
+export let foo = 42;

From f84d536e49b265136c3b493931116cf2d555f1a1 Mon Sep 17 00:00:00 2001
From: Caio Lima <caiolima@igalia.com>
Date: Thu, 19 Mar 2026 17:43:34 -0300
Subject: [PATCH 2/2] Adding test case when there's a setter on A.prototype

---
 .../super-set-to-tdz-binding-with-accessor.js | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 test/language/module-code/namespace/internals/super-set-to-tdz-binding-with-accessor.js

diff --git a/test/language/module-code/namespace/internals/super-set-to-tdz-binding-with-accessor.js b/test/language/module-code/namespace/internals/super-set-to-tdz-binding-with-accessor.js
new file mode 100644
index 00000000000..7c546b36afd
--- /dev/null
+++ b/test/language/module-code/namespace/internals/super-set-to-tdz-binding-with-accessor.js
@@ -0,0 +1,43 @@
+// Copyright (C) 2026 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-ordinarysetwithowndescriptor
+description: >
+    super.foo = V calls the accessor on super class instead of throwing
+    ReferenceError for TDZ binding
+info: |
+    OrdinarySetWithOwnDescriptor ( _O_, _P_, _V_, _Receiver_, _ownDesc_ )
+      ...
+      1. Assert: IsAccessorDescriptor(_ownDesc_) is *true*.
+      1. Let _setter_ be _ownDesc_.[[Set]].
+      1. If _setter_ is *undefined*, return *false*.
+      1. Perform ? Call(_setter_, _Receiver_, « _V_ »).
+      1. Return *true*.
+
+    NOTE: When the super class has an accessor property, the setter is called
+    directly and the Receiver's [[GetOwnProperty]] is never invoked, so the
+    module namespace TDZ binding is not accessed.
+flags: [module]
+features: [let]
+---*/
+
+import * as ns from './super-set-to-tdz-binding-with-accessor.js';
+
+var setterValue;
+
+class A {
+  constructor() { return ns; }
+  set foo(v) { setterValue = v; }
+};
+class B extends A {
+  constructor() {
+    super();
+    super.foo = 14;
+  }
+};
+
+new B();
+
+assert.sameValue(setterValue, 14, "setter on A.prototype should be called with the assigned value");
+
+export let foo = 42;