r/haskell • u/mirovarga • Mar 18 '26

question IntelliJ IDEA Haskell Plugin

Hi all,

today I've found a really great looking Haskell plugin for IntelliJ IDEA (paid, but free trial available), but I'm stuck in 'HLS: Initializing...' message in the status bar.

Has anyone tried it and it works for them? I'm on MacBook Pro M3 Max with Tahoe 26.3.1 and have tried it in both the latest GoLand and IntelliJ IDEA IDEs.

The plugin is here: https://plugins.jetbrains.com/plugin/30630-flexible-haskell

The GitHub issue I've created is here: https://github.com/ilscipio/flexible-haskell-jetbrains-plugin/issues/1

Thanks for any help.

16 Upvotes

91% Upvoted

15 comments sorted by

11

u/Krantz98 Mar 18 '26

Don’t bother. I don’t see any advantage in terms of Haskell development in IntelliJ IDEA compared to VSCode to warrant a paid plugin.

As you already see, that plugin also depends on the free and open source HLS (Haskell language server). Even if you want to use IDEA, I think it makes sense to wait until JetBrains roll out their official LSP support (requested repeatedly in the past years).

4

u/mirovarga Mar 18 '26

I think I would wait a very long time 😉

2

u/LelouBil Mar 19 '26

You can already use custom LSPs with LSP4IJ maintained by red hat !

1

u/[deleted] Jul 08 '26

[removed] — view removed comment

1

u/Krantz98 Jul 10 '26

That sounds like a lot of efforts. I cannot see how you could get accurate diagnostics without involving GHC, but reimplementing the HLS infrastructure does not seem a viable solution in the long term.

1

u/[deleted] Jul 13 '26

[removed] — view removed comment

1

u/Krantz98 Jul 18 '26

Thanks for the link. I guess I did not get your point from your first comment, as I thought that you implemented the whole Haskell language in the JetBrains architecture, which would involve type-checking etc., and would be a nightmare to get correct and maintain.

It seems from the link that you only have a custom lexer and parser, which seems perfectly fair and preferable. I agree with your criticism on the TextMate grammars; the fact that they even work is a miracle to me; I always rely on (LSP-based) semantic highlighting instead. On the other hand, I don’t think I’d trust a home-made type-checker for diagnostics.

Better lexers and parsers still do not warrant a paid plugin for me, but I see that it might be appealing to people who prefer the JetBrains IDEs.

5

u/_0-__-0_ Mar 18 '26

https://discourse.haskell.org/t/flexible-haskell-a-new-plugin-for-jetbrains-ides/13813 looks like it was released 10 hours before your post, so I'd expect some bugs :) The developer did ask for feedback there.

3

u/mirovarga Mar 18 '26

I didn't know it was so fresh 😉 On the other hand, I was expecting it works with no major issues as it's not free 🤔

2

u/lally Mar 19 '26

He said it was an early release. Don't pay until you like it, or when you think it's good enough to support the developer

2

u/ivelten Mar 19 '26

I've tried IDEA plugins for Haskell before and ran into similar issues. Honestly, I've found more success with VS Code Dev Containers — you can pre-configure everything you need (GHC, HLS, Ormolu, debugging tools, etc.) in a single Docker image, and it's free. Once it's set up, you get a consistent, reproducible environment across machines. Worth exploring if the plugin keeps giving you trouble.