Block comments converting to highlighted during navigation

[pmcevoy]

I frequently use block comments to disable sections of terraform code using /* to start disabling and */ to complete. As expected, the code will turn "grey" and lose syntax highlights.

However, when I move the cursor so that the opening /* scrolls off the top of the screen, the previously "grey" code suddenly starts highlighting again. If I stop moving and CTRL-L to redraw the problem goes away and the code goes "grey" again - although in some unidentified cases redraw never fixes this - it's a little frustrating as I never am sure what code is live or not.

I'm on Windows, using VIM 9.0, the vim-terraform pack, gruvbox colorscheme

I believe I did not have this issue to such a great extent with Vim 8.0. I recall attempting Vim 8.2 and reverting to 8.0 after a few days and I'm only seeing this issue again since updating to 9.0

(also submitted here https://vi.stackexchange.com/questions/42221/block-comment-syntax-colouring-being-lost-while-moving-but-redraw-will-fix)

[dimbleby]

you probably want something to do with syntax sync.

These days I use treesitter for my syntax highlighting so I'm not especially motivated to dig into this. However I'm open to merge requests, if you come up with something convincing.

[dimbleby]

some years ago I contributed https://github.com/nathanalderson/yang.vim/blob/0edaeb616be8f66caed2c888095446006fd4a6fa/syntax/yang.vim#LL107C1-L107C47 to another syntax to deal with a similar case, perhaps something like that here

but I admit that I forget now how or why that works