fix(es/compat): Fix handling of private members in optional chaining pass

[komyg]

Description:

Fix: #7561

Related issue (if exists):
#7561

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[kdy1]

This is wrong.

class Foo {
  #x;
  test() {
    this === null || this === void 0 ? void 0 : this.y.#x;
  }
}

Please try locally using

{
  "plugins": [
    "@babel/plugin-transform-optional-chaining"
  ]
}

This is how I got the expected output

[komyg]

Hey @kdy1,

On the original issue: #7561, @jridgewell says that this is the expected output:

// …
var _x = new WeakMap();
class Foo {
    test() {
        (_this = this) === null || _this === void 0
          ? void 0
          : _class_private_field_get(_this.y , _x);
    }
    // …
}

Also, isn't your output the same as mine, but without the transformation for the private field?

[komyg]

PS: I thought that the main problem was that we were not transforming the private field.

[kdy1]

No. Expected output of optional-chaining is mine. What you uploaded is output of full transforms.

[komyg]

I'm sorry, @kdy1, I don't think I understand your comment.

Here is the problem that I want to solve with this PR (please note that I haven't been able to actually solve it yet, this is why you only saw a test): whenever we have an optional chaining expression with a private field, the private field is not transformed (we don't replace it with: _class_private_field_get).

This is what I understood from these issues: #7561 and #7559.

Regarding your comment:

No. Expected output of optional-chaining is mine. What you uploaded is output of full transforms.

Do you mean that I've put the test in the wrong place? Since it is inside the optional chaining module, it shouldn't be testing private fields? If so, where would be the most appropriate place to put it?

Or do you mean that I am solving the wrong problem?

[kdy1]

whenever we have an optional chaining expression with a private field, the private field is not transformed

This is wrong. Private fields are transformed by another pass.

[kdy1]

The optional chaining pass should produce

class Foo {
  #x;
  test() {
    this === null || this === void 0 ? void 0 : this.y.#x;
  }
}

and another pass is responsible for the rest.

[komyg]

Ok, there are two problems?

One for the optional chaining and another for tge private field?

[kdy1]

No, private field transforms are working correctly

[komyg]

I've updated the test as you requested. I think it is correct now.

[komyg]

Hey @kdy1, I believe I have solved the problem. Could you review it please?

[kdy1]

Please remove this

[kdy1]

You don't need to add a new function with testing::fixture

[kdy1]

Just add a test file to the correct directory.

[komyg]

I think I've added it to the correct folder, now. Could you check, please?

[kdy1]

Thank you, nice work!

---

swc-bump:

• swc_ecma_transforms_compat

[swc-bot]

Automated review comment generated by auto-rebase script

[kdy1]

I'm reverting this commit with #7812