2 files changed, 5 insertions, 1 deletions
diff --git a/js/src/builtin/ModuleObject.cpp b/js/src/builtin/ModuleObject.cpp
index f7323e852..28a3329a8 100644
--- a/js/src/builtin/ModuleObject.cpp
+++ b/js/src/builtin/ModuleObject.cpp
@@ -345,6 +345,8 @@ bool
 ModuleNamespaceObject::ProxyHandler::setPrototype(JSContext* cx, HandleObject proxy,
                                                   HandleObject proto, ObjectOpResult& result) const
 {
+    if (!proto)
+        return result.succeed();
     return result.failCantSetProto();
 }
 
diff --git a/js/src/jit-test/tests/modules/import-namespace.js b/js/src/jit-test/tests/modules/import-namespace.js
index 71a1ce7df..27d0193aa 100644
--- a/js/src/jit-test/tests/modules/import-namespace.js
+++ b/js/src/jit-test/tests/modules/import-namespace.js
@@ -39,7 +39,9 @@ assertEq(getModuleEnvironmentValue(b, "x"), 3);
 
 // Test module namespace internal methods as defined in 9.4.6
 assertEq(Object.getPrototypeOf(ns), null);
-assertThrowsInstanceOf(() => Object.setPrototypeOf(ns, null), TypeError);
+assertEq(Reflect.setPrototypeOf(ns, null), true);
+assertEq(Reflect.setPrototypeOf(ns, Object.prototype), false);
+assertThrowsInstanceOf(() => Object.setPrototypeOf(ns, {}), TypeError);
 assertThrowsInstanceOf(function() { ns.foo = 1; }, TypeError);
 assertEq(Object.isExtensible(ns), false);
 Object.preventExtensions(ns);