decoratorVersion: '2023-11' — _get/_get_prototype_of helpers undefined when lowering static super field references

[Lookwe69]

Description

When using @swc/core with decoratorVersion: '2023-11' to lower TC39 standard (stage 3) decorators, static field initializers that reference super (e.g. static override styles = [...super.styles, extra]) produce code that calls _get() and _get_prototype_of() helpers — but those helpers are not inlined into the output and not imported from @swc/helpers. This causes a ReferenceError at runtime.

This issue was previously reported as #11780 and that issue is now closed, but the bug is still present in @swc/core@1.15.26.

Reproduction

import { LitElement, css } from 'lit';
import { customElement } from 'lit/decorators.js';

const myStyles = css`div { color: red }`;

@customElement('test-derived')
class TestDerived extends LitElement {
  static override styles = [...super.styles, myStyles];
}

Transform config:

swc.transformSync(code, {
  filename: 'test.ts',
  jsc: {
    parser: { syntax: 'typescript', decorators: true, decoratorsBeforeExport: true },
    transform: { decoratorVersion: '2023-11' },
    target: 'es2022',
  },
});

Actual output (relevant excerpt)

function _identity(x) { return x; }

// _get and _get_prototype_of are NEVER defined or imported

let _dec, _initClass, _LitElement, _fieldValue;
_dec = customElement('test-derived'), _LitElement = LitElement;
let _TestDerived, _TestDerived_member;
new class extends _identity {
    constructor(){
        super(_TestDerived), _initClass(), _TestDerived_member = _TestDerived;
    }
    static [class TestDerived extends _LitElement {
        static {
            ({ c: [_TestDerived, _initClass] } = _apply_decs_2311(this, [_dec], [], 0, void 0, _LitElement));
        }
        static {
            _fieldValue = function() {
                return [
                    ..._get(_get_prototype_of(_TestDerived), "styles", this),
                    //  ^^^^ ReferenceError: _get is not defined
                    myStyles
                ];
            };
        }
    }];
    styles = _fieldValue.call(this);
}();

Expected output

The _get and _get_prototype_of helpers should either be:

• Inlined alongside the other helpers (_identity, _apply_decs_2311, etc.), or
• Imported from @swc/helpers

Runtime symptom

When this pattern appears in a class that also has other static fields (e.g. Lit's static shadowRootOptions = { mode: 'open' }), the ReferenceError thrown during class initialization prevents all static fields from being set. In Lit components, this surfaces as:

Uncaught TypeError: Failed to execute 'attachShadow' on 'Element':
Failed to read the 'mode' property from 'ShadowRootInit': Required member is undefined.

Environment

• @swc/core: 1.15.26
• Node: 24.x
• Related closed issue: [decorators 2023-11] static field with super reference incorrectly moved to wrapper class instance field #11780