private elements: tests for private method semantics usage

[jbhoosreddy]

Tracking issue: #1343

Summary of changes:

1. Reading a private method separately from calling it
   • All instances of the class share the same function identity for the private method
2. The .name property of the private method is "#foo"
3. It's OK at parse-time to reference a static private method from an instance method, or vice versa, and you can make use of this at runtime with creative application of Function.prototype.call.

[jbhoosreddy]

@mkubilayk for initial review

[rwaldron]

This renders inside the class body:

var C = class {
  *m() { return 42; } #m() {};
  method() {
    return this.#m;
  }

  const c1 = new C();
  const c2 = new C();

}

[rwaldron]

Please use the "default" templates, as "productions" will render tests that will contain a bunch of unnecessary and irrelevant code.

[rwaldron]

As requested in the previous review comment, please use the "default" template. This will produce a test that looks like this:

var C = class {
  static m() { return 42; } #foo() {};
  method() {
    return this.#foo;
  }
}

var c = new C();

assert.sameValue(C.m(), 42);
assert.sameValue(Object.hasOwnProperty.call(c, "m"), false);
assert.sameValue(Object.hasOwnProperty.call(C.prototype, "m"), false);

verifyProperty(C, "m", {
  enumerable: false,
  configurable: true,
  writable: true,
});

assert.sameValue(c.method().name, '#foo');

When it really only needs to produce a test that looks like this:

var C = class {
  #foo() {};
  method() {
    return this.#foo;
  }
}

var c = new C();

assert.sameValue(c.method().name, '#foo');

[leobalter]

The tests need a bit more work. It also needs some other fixings as pointed by @rwaldron

[leobalter]

The description should tell what's being verified in this test, I can't read this and tell anything.

[leobalter]

This text doesn't match the test contents

[leobalter]

This needs adding the matching reference from the spec that allows this in the desc/info above. Otherwise it's hard to tell the goal of this test. The top comment on this PR clarified it a bit for me.

This needs adding a group of tests that assert other behaviors:

• when the function is called with other values, like this.#foo.call(this), this.#foo.call({}), this.#foo.call(null), C.#bar.call(C), including other values as the instance variable name (instead of this), undefined, etc etc
• other possible private methods.
• fields with function values, perhaps?

[leobalter]

this can (and should) also be verified for other methods types including assessor methods

[leobalter]

this is also not testing the name property

[leobalter]

I believe we already have tests to assert the method relationship with the class prototype? In this case, it should be good to assert which object has their own property and the shared relationship.

[jbhoosreddy]

thanks for the review. making revisions now.

[jbhoosreddy]

I'm temporarily closing this.. need some time to look at it.