Volar 1.6 and 1.7 very slow for large project

[Doeke]

I have a large Vue 3 + Typescript project. Since updating Volar to 1.6.x, the performance of Volar took a nosedive. If I make any edit in .vue files, it takes up to 20 seconds for linting and syntax highlighting to be updated. There is no performance issue when editing .ts files in the same project, so I don't think the typescript server is the limiting factor. If I downgrade Volar to 1.2.x or 1.4.x, the performance is fast again.

It would be difficult for me to make this into a reproduction repo, are there other steps I can take to help debug this issue? Which features or changes in 1.6 could be responsible for such a decrease in performance?

[rdunk]

Having the same issue with both v1.6.5 and v1.7.8, taking ~35 seconds for updates to appear after changes.

[johnsoncodehk]

Related to #3148.

I think this is most likely caused by #2685, but I can't confirm this, I hope someone can provide a repro case, so I can add tests based on it to avoid future regressions.