lsp inlay hints

[MangoIV]

Feature description

It would be super cool if you could support the new lsp inlay hints for code lenses, they look much better than what we have now. I also wonder if there's a possibility to make code lenses look a tad nicer, e.g. not include control sequences and excessive amounts of white space (especially in imports).

This will start working with neovim version 0.10!

Thanks for considering!

[MangoIV]

Ah I think this is something to be supported by the hls? What kinda thing are the virtual text then? Why are they not supported by neovim proper? Hmmmm

As always I’m kinda confused

[mrcjkb]

Hey 😄

inlay hints and code lenses are different LSP requests.
It's on the hls roadmap, but I have no idea when it will be done haskell/haskell-language-server#2938.

Activity seems to have picked up recently though.

[MangoIV]

haskell/haskell-language-server#4131

There’s a GSOC student working on this!

[mrcjkb]

What kinda thing are the virtual text then?

The virtual text you're seeing are code lenses. It's another LSP specification, which I believe has existed for longer than inlay hints.
That would explain why hls implemented a lot of things as code lenses, for which inlay hints would be a better fit today.

The main difference is that code lenses come with an action (e.g., you can evaluate doctest snippets, or add imports or type signatures).

[MangoIV]

Do you know what’s up with the control sequences and the spaces on code lenses? Is that something that hls does wrong? Or is this something that happens because all of these guys are written for vscode?

[mrcjkb]

I'm not sure. VSCode does display code lenses differently than neovim, because neovim as a tui doesn't support different font sizes.
They are a lot smaller in vscode, so I guess that could be the reason.

[MangoIV]

do you just get these as strings?

[mrcjkb]

haskell-tools doesn't do much, besides enable and auto refresh code lenses by default.
The feature itself is implemented in neovim.

[MangoIV]

interesting, why is it that the standard lsp client doesn’t display these then? Also do you know where I’d have to go with these issues? I e what may cause the visual noise displayed in some of the code lenses?

[mrcjkb]

why is it that the standard lsp client doesn’t display these then?

I think that's just a decision by the maintainer. It could add quite a bit of noise and be too controversial to be enabled by default in neovim core.
@mfussenegger, maybe you can answer this better than I can? 😄

I e what may cause the visual noise displayed in some of the code lenses?

I'm not sure there's a good solution to this, because it would involve overriding vim.lsp.codelens.on_codelens.
I do this in my personal config, to add a prefix to the title, but I never really noticed any noise - Do you have a concrete example/screen shot?).
That would be too hacky for haskelll-tools though.

[MangoIV]

this is an example. It has weird amount of spaces, no?

[MangoIV]

There’s also the case where it renders “line breaks” in inferred type signatures.

[MangoIV]