RLS support thread

[jasonwilliams]

Sublime Text Version

3144

Rust Enhanced Version

2.2.0

hey @ehuss thanks for your work on the new error message layout, really enjoying using it today.
I was wondering what your thoughts were on auto complete for package names when typing in use std::etc::etc.

Is it something that could utilise language server? Or should we pass in a list of possible names to autocomplete.
Its something i attempted before but never got anything working, i think at this point you know more about the sublime internals than me.

[ehuss]

I think the long term solution is to use RLS. However, I have had very little luck getting it to run properly. Currently it is just crashing for me. I just learned that RLS is not often updated on nightly, so I think I need to install it from GitHub. Generally my experience with RLS has been very frustrating.

There are a few other Sublime plugins that provide completion:

• RustAutoComplete uses Racer and seems to work, though the project seems to be dead.
• Anaconda Rust also works using Racer. This also provides linting, documentation, goto definition, formatting, etc. However, I've had a lot of problems getting this to work properly. I personally use Anaconda for Python work, though.

It would be fairly easy to hard-code the completions for std, but I don't think that would be worthwhile. I've mostly been waiting for the dust to settle with RLS to give it a shot, but each time I try, it doesn't work properly. I'll toy around with RLS some more. There was some recent work the past few days that I want to try out.

I'm also wondering what the best long-term solution is for RLS integration. The LSP plugin seems decent and is getting active development, however I don't know if it will have a complete Rust experience. For example, I don't know how it will handle formatting Rust's error messages which can be quite complex. I'm wondering if a custom RLS client would be useful, perhaps leveraging the LSP plugin just for the JSON communication. RLS also has some custom messages, and some messages like workspace/DidChangeConfiguration may need some Rust-specific smarts. I think it would be a fun project, so I'd be happy to work on it, I'm just uncertain if it is really needed or if anyone would prefer a Rust-specific implementation.

[urschrei]

RustAutoComplete is currently better than RLS, but the lack of std:: completions was down to a bug in Racer (racer-rust/racer#799), so whenever that gets merged, released and incorporated into RLS, things should improve.

[jasonwilliams]

Interesting, maybe we should give RLS another shot. I haven't been up to date on its progress to be honest, but i can always toy around with it.

I have no idea how it would be integrated, is it something our plugin can set up on its own without needing a second LSP plugin for sublime?

[dten]

Confused why we need a rust specific version of LSP? That goes against the whole idea of LSP. 1 server per language, 1 plugin per editor. Done.
If you want to improve something go help on the LSP plugin or the RLS

[jasonwilliams]

@dten could you explain a bit more about the split? And is it possible for Rust Enhanced to take advantage of any work done in the LSP Plugin?
Is it not possible to have our plugin use the same language server? (im still trying to get my head around the setup here)

Obviously we don't want to reinvent the wheel, but would like to make use of any features that come out.

[dten]

So I assume you've read https://langserver.org/ etc and get the idea of the n + m implementations rather than n*m

So VS Code obviously started this off and it provides a library for interacting with LSP services. The Rust plugin for VS Code uses the library but adds functionality to easily install RLS
Annoyingly Microsoft made a typescript plugin for Sublime that uses the protocol but did not make it easily re-usable.

the LSP Sublime plugin is one of a few plugins that have tried to implement LSP in a proper language agnostic way as it should be done. Obviously though there is a little extra setup of install rls and add the settings to LSP's settings. LSP comes with some default settings but currently it's a little awkward for RLS because you often want to use a nightly version etc which means calling a different RLS. In theory that side of things should just come with LSP and it won't be an issue.
That just leaves installing RLS which, isn't very hard but we could offer a command for.

In theory (i think) we can depends on RLS so it gets installed with Rust Enhanced, I might be way off on that though.

We're currently doing some of the work RLS should be doing because it's not ready yet, in theory it should be better at providing live errors than running cargo check. No harm having both at the moment though

[jasonwilliams]

@dten there's been some questions about RLS here:
https://www.reddit.com/r/rust/comments/7cmsjl/rust_enhanced_the_official_rust_package_for/
https://users.rust-lang.org/t/rust-enhanced-the-official-rust-package-for-sublime-text-3/13846/2

I've tried to divert people here, but feel free to answer any Q's

[jasonwilliams]

@dten ok so plan 1 is to bring down RLS and have a rust nightly chain switched on?
Then what do we do about Sublime LSP? Are we feeding into that or talking to RLS directly, I’m not sure how sublime lsp and rust enhanced co-exist.

perhaps leveraging the LSP plugin just for the JSON communication

Is that possible?

.

[urschrei]

RLS is on the way (I believe) to being available in Stable, so it's probably best to wait for that rather than dealing with workarounds and Nightly requirements etc. We could make a command available to install it via Rustup, or note that it's required.
One of the other things that's missing is RustEnhanced syntax support in the default LSP Rust config – although it's just a simple PR to add it here.

[jasonwilliams]

I should be able to fix that, @urschrei you on irc at all?

[urschrei]

@Jayflux Yep, same nick on #rust

[jasonwilliams]

I've had a chat with @urschrei today.
We now have instructions on how to set up RLS which im hoping to PR
I've made a note that this is experimental right now, but its for those who are hoping to do any development on it.

https://github.com/rust-lang/rust-enhanced#rls

@urschrei will be adding PRs to LSP to make the process a bit smoother

@nrc @alexheretic @jonasbb it would be awesome if Sublime Text 3 was added to RLS's testing setup