I don't understand what's going on with CI, is this related to PR?

Thanks for the PR. I will get to this in a little bit--I'm looking at switching to a new, mostly compatible sourcemap library which at minimum will cause some merge conflicts here, but I will get it merged.

Thanks again, I extended this in #1481 to avoid computing the whole set of column spans and just using the next mapping as we iterate (IeachMapping ensures order)

Sorry, there seems to be an issue with this PR. (may block publishing)
It seems that some generator sourcemaps may have inaccurate identifier ranges.
For example (aaaa), some generators may generate aaaa) as an item.
I fear this PR will make this worse.
Maybe we can introduce a detection to allow fallback, we use regex to detect all text in the identifier range, if it contains ,),,, then let us fall back to using regex logic. (maybe allow .)
Also I realize there's a possible problem with the new logic treating member expressions as allowing previews, which has the slightest chance of side effects (getters), but that's probably fine since we're using the location in the source code to look for, which means that only compiler-generated member expressions are previewed.

hm, thanks. For now I think I will just go back to the original approach, and modify the regex to allow member access with .