Zed and ReScript Language Server Woes

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Not exactly where I should report this as I’m not 100% it’s an issue with the LSP or the editor integration or what. I’m running ReScript 12.0.1 and version 1.70.0 of the language server. When I open a file in Zed, the diagnostics that show are correct. When I change the file, the indicators showing the diagnostic issues don’t change or disappear.

Here’s before and after a save showing the LSP RPC log. You can see stale diagnostics in the first photo and saving it autoformats the code but still seems to show stale diagnostics in the LSP RPC. (You can tell it’s stale in the second pic because the squiggly is misaligned.)

CleanShot 2025-12-16 at 19.59.25@2x
CleanShot 2025-12-16 at 19.59.25@2x3248×2120 800 KB

CleanShot 2025-12-16 at 20.00.08@2x
CleanShot 2025-12-16 at 20.00.08@2x3248×2120 790 KB

I think this means the LSP is misbehaving, but I’m suspicious no one has reported an issue regarding this in three weeks. Anyone with more knowledge know better?

Also, hi @jderochervlk. :wave:

Edit: I’ve just confirmed that it works fine in VSCode, so leaning towards this being a Zed integration issue.

2 Likes
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Do you have autosave there as well?

Oh and do you have any configuration in zed?

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I ended up opening an issue on the rescript-zed project and we’ve at least got a workaround now.