Haskell Syntax highlight break when write a type signature with "=>" sign

[foxmean]

Summary

Around 95% up when I write a type signature with "=>" sign, the syntax highlight is break. Everything is recover when I quite and reopen the helix as show below.

Reproduction Steps

I tried this:

1. Open the helix editor and write some Haskell script
2. Everything worked just fine except when I wrote a type signature that included "=>" sign (mostly). I usually not happen when I haven't included "=>".
3. When I save and restart helix, everything fixed. But it is annoying.

I expected this to happen:
The syntax highlighter maybe break due to incomplete writing since it haven't happened if I wrote the function definition before type signature as show below

Instead, this happened:
When I wrote a type signature before the function definition

Helix log

A copy of ~/.cache/helix/helix.log here (with RUST_BACKTRAACE=1 hx -vv when reproducing bug. I have no idea how to summary these lines but I have selected only line that I reproduced the bug here.

Platform

MacOS Sonoma 14.6.1; on MacBook Air M1, 2020

Terminal Emulator

iTerm2, Build 3.5.0 (without terminal multiplex); and Alacritty Version 0.13.2 (1) with Zellij 0.40.1. Both terminal was installed via homebrew cask. Zellij was installed via nixpkgs (nix-darwin)

Installation Method

nixpkgs through nix-darwin flake

Helix Version

helix 24.7 (079f544)

[kirawi]

We disable highlighting on a buffer if highlighting takes longer than half a second to compute. It sounds to me like => has some buggy behavior here. We could see if a newer commit for the grammar has resolved this issue.

[foxmean]

Sorry for the last archived video. I can reproduce some of the bug related to just "->" too like.

BTW, I think the bug is from HLS itself due to I can reproduce it in Zed editor.
I use GHC 9.10.1 with HLS 2.9.0.1 from GHCup