Private field not recognized inside an enclosing class

[joelhecht]

Bug report

Hello,
It seems that there's a regression when handling with private fileds introduced in version 5.16.0.
I did not encounter this problem with version 5.15.1.

Version (complete output of terser -V or specific git commit)
terser 5.16.0

Complete CLI command or minify() options used
npx terser my-class.js

terser input

Content of my-class.js file:

class My_class {
    #private_field = 123;

    fn() {
        const c = new (class b {})(); // <-- removing this line removes the parse error
        return this.#private_field;
    }
}

terser output or error

Parse error at my-class.js:6,14
                return this.#private_field;
                            ^
ERROR: Private field must be used in an enclosing class
    at js_error (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:554:11)
    at croak (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:1278:9)
    at subscripts (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:3235:17)
    at expr_atom (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:2556:20)
    at maybe_unary (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:3374:19)
    at expr_ops (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:3425:24)
    at maybe_conditional (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:3430:20)
    at maybe_assign (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:3507:20)
    at expression (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:3532:24)
    at statement (C:\dev.local\ui-test\packages\atomics\node_modules\terser\dist\bundle.min.js:1491:29)

Expected result
(obtained with terser 5.15.1)

class My_class{#private_field=123;fn(){const c=new class b{};return this.#private_field}}

[fabiosantoscode]

Thanks for reporting this!

[iz-iznogood]

Hello,

we are experiencing the same error when using terser plugin in webpack
Any chance of a workaround?
I cannot locate the problematic file, the project is very large

Thanks