JSTests/test262/test/language/statements/class/elements/privatefieldset-typeerror-1.js

// Copyright (C) 2017 Valerie Young. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
description: TypeError when setting private field before the entry was added to [[PrivateFieldValues]]
esid: sec-putvalue
info: |
  PutValue ( V, W )
    ...
    6. Else if IsPropertyReference(V), then
      ...
      b. If IsPrivateReference(V), then
        i. Let env be the running execution context's PrivateNameEnvironment.
        ii. Let field be ? ResolveBinding(GetReferencedName(V), env).
        iii. Assert: field is a Private Name.
        iv. Perform ? PrivateFieldSet(field, base, W).

  PrivateFieldSet (P, O, value )
    1. Assert: P is a Private Name value.
    2. If O is not an object, throw a TypeError exception.
    3. Let entry be PrivateFieldFind(P, O).
    4. If entry is empty, throw a TypeError exception.

  PrivateFieldFind (P, O)
    1. Assert: P is a Private Name value.
    2. Assert: O is an object with a [[PrivateFieldValues]] internal slot.
    3. For each element entry in O.[[PrivateFieldValues]],
      a. If entry.[[PrivateName]] is P, return entry.
    4. Return empty.

features: [class, class-fields-private, class-fields-public]
---*/

class C {
  y = this.#x = 1;
  #x;
}

assert.throws(TypeError, function() { new C(); })