no-unnecessary-polyfills: always triggered on core-js/{actual,full}/<feature>

[andreww2012]

Hello! If the environment doesn't support <feature>, when I import from core-js/actual/<feature> or core-js/full/<feature>, no-unnecessary-polyfills rule is incorrectly triggered, but if I import it from es or stable, it is not.

Example:

// Reported - but the environment doesn't support `Array.prototype.toSpliced`:
import 'core-js/actual/array/to-spliced';
import 'core-js/full/array/to-spliced';

// Not reported as expected:
import 'core-js/es/array/to-spliced';
import 'core-js/stable/array/to-spliced';

Full reproduction: https://stackblitz.com/edit/vitejs-vite-zrgjkh?file=src%2Fmain.js

pnpm test

[fregante]

no-unnecessary-polyfills rule is incorrectly triggered

Why would that be incorrect?

// Reported:
import 'core-js/actual/array/to-spliced';

If you include this in an environment that has Array#toSpliced, then it is unnecessary.

if I import it from es or stable, it is not

This part sounds like the bug.

[andreww2012]

Sorry, I think I meant to say "correctly".

Upd: actually it was implied that the environment doesn't support the feature. Made my initial message more clear. Either way the rule should not report any or report all the 4 imports 🙂