The changes overall look reasonable. However,

• I suspect there are some vestiges of the old logic still lingering in the code that was ported over from the old parser. And seems like this could result in incorrect / missing errors (e.g. in the {{$guid $guid}} case). The comments around these functional aspects seem like the most important ones to address first.

• We are also missing tests for some of the new error messages and for some negative cases such as the {{$guid $guid}} case above. It would be great to include some tests for these missing cases.

• Other than that, most of the comments are around code hygiene, some improvements for the error messages we report and some improvement for tests. I am ok with fixing these up in follow up PRs (so long as we fix up the error messages during the preview releases of the new parser integration).

The changes look good, and the test coverage is much improved now.

However, I found a couple of bugs and few more cases that need tests. I am fine with merging the PR so long as the corresponding comments are addressed. Please take a look.

Looks like you may have missed some of the comments because GitHub collapses them by default in the discussion view. Let's sync up tomorrow.

👍🏾 Looks great. Thanks for adding test coverage for all the cases!