Test that Error.prototype has no [[ErrorData]] slot

test/built-ins/Error/prototype/no-error-data.js

@@ -0,0 +1,34 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-properties-of-the-error-prototype-object
+description: >
+  The Error Prototype object does not have a [[ErrorData]] internal slot.
+info: |
+  Properties of the Error Prototype Object
+
+  The Error prototype object:
+  [...]
+  * is not an Error instance and does not have an [[ErrorData]] internal slot.
+
+  Object.prototype.toString ( )
+
+  [...]
+  8. Else if O has an [[ErrorData]] internal slot, let builtinTag be "Error".
+  [...]
+  15. Let tag be ? Get(O, @@toStringTag).
+  16. If Type(tag) is not String, set tag to builtinTag.
+  17. Return the string-concatenation of "[object ", tag, and "]".
+features: [Symbol.toStringTag]
+---*/
+
+// Although the spec doesn't define Error.prototype[@@toStringTag], set it
+// to non-string anyway because implementations are allowed to define it.
+Object.defineProperty(Error.prototype, Symbol.toStringTag, {
+  value: null,
+});
+
+assert.sameValue(
+  Object.prototype.toString.call(Error.prototype),
+  "[object Object]"
+);