[ANN] haskell-language-server-1.5.0 release


Time for another hls release:

  • @pepeiborra has done an epic work to improve performance, redefining some of the core pieces of HLS
    • You can take an overall look to improvements in these slides
    • Performance would be noticeable in large projects without too much template haskell usage
  • We have fourmolu support for ghc-9.0.1 thanks to @georgefst
  • We have got improvements over import suggestions thanks to @yoshitsugu and @alexnaspo
  • Completions also has been improved in general thanks to @pepeiborra
  • There have been lot of documentation updates by several contributors, thanks also to all of you
  • In this release we still don’t have full support for all plugins and ghc-9.0.1
    • Missing plugins for ghc-9.0.1 are: hls-class-plugin, hls-tactics-plugin (wingman), hls-brittany-plugin and hls-stylish-haskell-plugin

Deprecation notice for 1.5.0

  • As we noted in the previous release we have dropped support for ghc versions 8.6.4, 8.10.2, 8.10.3, 8.10.4 in this release
  • We will drop support for ghc versions 8.10.5 and 8.8.3 after this release
  • The advise is upgrade ghc to the last minor version: 8.6.5, 8.8.4 or 8.10.7
  • You can read more about ghc deprecation policy and schedule here

I’m so thrilled to be using HLS now – and happy to see progress toward performance improvements.

If I may ask a silly question: I installed HLS from within VS Code. (I actually don’t remember the exact details. I just installed VS Code and then clicked some button saying I wanted to program in Haskell. Everything was basically automatic, which was positively lovely.) How do I upgrade?


It should download the new version automatically the next time you open vscode after the github release. But you have to ensure there is no haskell-language-server-wrapper in $PATH (f.e. installed with ghcup)

There has been detected a bug in the new release involving hs-boot files.
The bug has been observed in ghc but other projects using those files could be affected: HLS 1.5 appears to not handle hs-boot files correctly · Issue #2365 · haskell/haskell-language-server · GitHub
We are working on fix it, sorry for the inconveniences

Even more loveliness. You have a happy customer here. Thanks for making this easy.