Pervasive Duplication in VSCode Extension

[wenkokke]

Your environment

Which OS do you use?
MacOS Ventura (13.7)

Which version of GHC do you use and how did you install it?
GHC versions from the 9.4, 9.6, and 9.8 series installed via ghcup.

How is your project built (alternative: link to the project)?
Various projects built using Cabal.

Which LSP client (editor/plugin) do you use?
VSCode and VSCodium with haskell.haskell.

Which version of HLS do you use and how did you install it?
HLS version 2.9.0.1 installed via ghcup.

Have you configured HLS in any way (especially: a hie.yaml file)?
Various projects with and without hie.yaml files.
Consistently configured to discover GHC and other tools via the PATH.

Observed behaviour

The VSCode language extension for Haskell pervasively duplicates responses. This manifests in various ways:

• Duplicated Quick Fix suggestions.

  

• Overlapping Instance errors pointing to the same instance twice.
  Incorrect overlapping instances errors #3694

  

• ...

Unfortunately, the issue does not always happen. However, I can attest that it is not exclusively triggered by opening out-of-workspace files—which I don't generally do—or opening multiple workspaces concurrently—which I do often do.

Steps to reproduce

I do not currently have a way to reproduce the behaviour, but can look into this once we hone in on a particular issue.

NOTE: I am opening this issue now, but I'll continue to add evidence as I gather it.

[fendor]

Thank you for opening this issue!

We additionally track this issue in haskell/vscode-haskell#480

[wenkokke]

Thank you for opening this issue!

We additionally track this issue in haskell/vscode-haskell#480

Yes, I believe they're likely related. However, I didn't see my observations of duplicate suggestions and overlapping instance errors reproduced there, so I opened a new issue.

[fendor]

Overlapping Instance errors pointing to the same instance twice.

That's a different issue #3694, I don't think that's part of the duplication issue.