JSTests/test262/test/language/statements/class/subclass/class-definition-null-proto-this.js

// Copyright (C) 2014 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-runtime-semantics-classdefinitionevaluation
description: >
  The `this` value of a null-extending class is automatically initialized
info: |
  The behavior under test was introduced in the "ES2017" revision of the
  specification and conflicts with prior editions.

  Runtime Semantics: ClassDefinitionEvaluation

  [...]
  5. If ClassHeritageopt is not present, then
     [...]
  6. Else,
     [...]
     e. If superclass is null, then
        i. Let protoParent be null.
        ii. Let constructorParent be the intrinsic object %FunctionPrototype%.
  [...]
  15. If ClassHeritageopt is present and protoParent is not null, then set F's
      [[ConstructorKind]] internal slot to "derived".
  [...]

  9.2.2 [[Construct]]

  [...]
  5. If kind is "base", then
     a. Let thisArgument be ? OrdinaryCreateFromConstructor(newTarget,
        "%ObjectPrototype%").
  [...]
---*/

var thisVal, instance;

class C extends null {
  constructor() {
    thisVal = this;
  }
}

instance = new C();

assert.sameValue(instance instanceof C, true);
assert.sameValue(instance, thisVal);