1 files changed, 30 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/statements/class/poisoned-underscore-proto.js b/js/src/tests/test262/language/statements/class/poisoned-underscore-proto.js
new file mode 100644
index 0000000000..5f71e08af1
--- /dev/null
+++ b/js/src/tests/test262/language/statements/class/poisoned-underscore-proto.js
@@ -0,0 +1,30 @@
+// Copyright (C) 2019 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: prod-ClassDeclaration
+description: >
+  ClassDeclaration should directly set [[Prototype]] internal slot.
+info: |
+  ClassDefinitionEvaluation
+
+  [...]
+  7. Let proto be ObjectCreate(protoParent).
+
+  ObjectCreate ( proto [ , internalSlotsList ] )
+
+  [...]
+  4. Set obj.[[Prototype]] to proto.
+features: [class]
+---*/
+
+Object.defineProperty(Object.prototype, '__proto__', {
+  set: function() {
+    throw new Test262Error('should not be called');
+  },
+});
+
+class A extends Array {}
+
+assert.sameValue(new A(1).length, 1);
+
+reportCompare(0, 0);