Clarify test262 coverage

[rwalle]

swc_ecma_parser documentation page says:

Passes almost all tests from tc39/test262

Can we get the coverage of test262? I think the information is very important to potential users -- they want to know what "almost all" refers to and if this is ready for serious projects. It would be better to write out known limitations.

I actually tracked down the test in crates/swc_ecma_parser/tests/test262.rs. Looks like this file needs some maintenance -- if I comment out the first item 431ecef8c85d4d24.js in IGNORED_PASS_TESTS the test still passes, but not 3dabeca76119d501.js in the "annex B" area. The test directly skips anything that is in "ignored". I wonder if the test should be written in such a way that it expects these things to fail instead of ignoring them all together? This way, if a file can be parsed, it must be removed from the list

[kdy1]

All specs are implemented, excluding Annex B, which is an extension rather than a standard. The documentation should be updated. Can you send a PR?

[rwalle]

Sure, I'll try something in the next few days

[rwalle]

@kdy1 Looks like the documentation needs a bit more work -- my understanding is that swc_ecma_parser also support JSX. Could you confirm

• JSX is fully tested
• most TypeScript tests pass with exceptions here

Also, could you address the question above -- it seems that many of the items in IGNORED_PASS_TESTS are outdated and come from 4 or 7 years ago (git blame). I would do this separately, but do you think this should use some clean up and stricter logic to avoid false negatives?