lsp-haskell VS haskell-language-server

Were you using emacs-lsp?

If you're interested in complete setups, my haskell-mode configuration is here, general lsp-mode (I also have an eglot setup, but that's just local for now) is here and Haskell-specific lsp-mode settings (fixing, among other things, stuff like this issue) are here.

It is Emacs with lsp-haskell

I think this is a problem with haskell language server. Also, there seems to be something missing in lsp-haskell indicated by the null errors but most likely it is not related to code actions. It is best to open an issue in https://github.com/emacs-lsp/lsp-haskell .

The advent of language server protocol made possible the creation of HLS (Haskell Language Server), and there are plugins for many editors, such as vscode-haskell, that allow you to have auto-complete, auto-import, and automatic function signatures—also available to your editor of choice. The whole feedback loop of editing, compiling, and running is greatly improved.

HLS 2.3.0.0 is currently broken on Windows.

The Haskell community has been focusing on tooling and IDE support in the last several years. Haskell-Language-Server is a huge improvment, so the experience is probably much better than you remember, but it'll still be a while before it catches up with Rust.

static-ls is a low memory language server for Haskell that serves as an alternative to (hls)[https://github.com/haskell/haskell-language-server] with less functionality by using statically generated information. It is intended for (Highly recommend hls instead if you aren't having these issues):

I think the corresponding HLS PR is https://github.com/haskell/haskell-language-server/pull/3462, so it isn't landed yet but hopefully can be part of a HLS release before too long. (I'm not sure if it will make it in to the very next release because we're due one out to support GHC 9.6.1 pretty soon.)