HLS >= 2.6 never prints any diagnostics for a bigger project

[carbolymer]

Your environment

Which OS do you use?

ArchLinux

Which version of GHC do you use and how did you install it?

9.8.2 from GHCUp

How is your project built (alternative: link to the project)?

cabal, see repro steps

Which LSP client (editor/plugin) do you use?

Neovim + haskell-tools.nvim

Which version of HLS do you use and how did you install it?

2.7.0.0 from https://aur.archlinux.org/packages/haskell-language-server-static

Have you configured HLS in any way (especially: a hie.yaml file)?

Using default configuration and this hie.yaml: https://github.com/input-output-hk/fusion-flamingo/blob/mgalazyn/hls-2.7-test/hie.yaml

Steps to reproduce

1. You need to have blst, sodium and secp256k1 installed on your system to successfully compile cardano-node: https://github.com/input-output-hk/cardano-node-wiki/wiki/install#installing-dependencies

2. Clone sample repository with the submodules:

   git clone --depth 1 --branch mgalazyn/hls-2.7-test --recurse-submodules -j8 [email protected]:input-output-hk/fusion-flamingo.git

3. Enable direnv configuration. Build the project.

   cd fusion-flamingo
   direnv allow
   cabal build all

4. Open your editor in the cardano-node working directory, and open the file cardano-testnet/src/Parsers/Run.hs. I'm using neovim:

   cd cardano-node
   nvim cardano-testnet/src/Parsers/Run.hs

Expected behaviour

Diagnostics are eventually shown.

Actual behaviour

Diagnostics are never shown, HLS is stuck on 100% CPU usage.

The issue occurs on HLS >= 2.6. HLS 2.5 + GHC 9.6.3 is working fine.

Debug information

0-haskell-language-server.log

[michaelpj]

Seems similar to #4046

[carbolymer]

@michaelpj Thanks for linking that issue. I think this one's a duplicate then. I've applied this patch #4046 (comment) and my HLS works again. I'll close this issue in favour of #4046.