Inline type inference

[jestarray]

Is there a way to get the type inference to be displayed inlined like vscode? Or is this not supported?

[jestarray]

Someone said this could be implemented with "conceal text".

[theHamsta]

The inlay hints are requested by a custom request (rust-analyzer/inlayHints) https://github.com/rust-analyzer/rust-analyzer/blob/17dda0972a68dd88a766c223390317dc2cb3ea00/editors/code/src/inlay_hints.ts#L135-L148

I think conceal can only hide text. I think we need to wait until virtual text gets extended in Neovim to be displayed not only in at the end of line but also in the middle. I think this was planned when merging the virtual text commit.

[akhilman]

Is it possible to have at least an annotation at the end of the line like CoC has?

Also can someone point to the neovim issues about virtual text?

[martskins]

@akhilman I think that would be fairly simple to implement. It's very specific to rust-analyzer, but we handle extensions already so I suppose we could add this one as well.

[martskins]

@akhilman see #1108 😄

If you could check out my branch, build from source and verify that it works as you'd expect that'd be great. I'll merge after I giving it a more in-depth try but I think it should be enough.

[ibraheemdev]

Was support added in #1106? I can't get it to work with the following config:

let g:LanguageClient_serverCommands = {
     \ 'rust': {
     \   'name': 'rust-analyzer',
     \   'command': ['rust-analyzer'],
     \   'initializationOptions' : {
     \       'inlayHints': {
     \           'enable': v:true,
     \           'chainingHints': v:true
     \       }
     \   },
     \ },
     \}

[martskins]

@ibraheemdev it works for me with that exact configuration. Which version of rust-analyzer and language-client-neovim are you using?

[ibraheemdev]

@martskins I built rust-analyzer from master and languageclient-neovim from next:

Plug 'autozimu/LanguageClient-neovim', {
   \ 'branch': 'next',
   \ 'do': 'bash install.sh',
   \ }

rust-analyzer.inlayHints are working for me with coc.nvim.

[martskins]

I see the same behaviour if I compile rust-analyzer from master. Latest release worked for me though, so maybe worth asking in rust-analyzer if something changed in master regarding chaining hints or if maybe you need to do something else to get those when compiling yourself.

[Logarithmus]

@akhilman @ibraheemdev @martskins not sure it's still relevant, but I also had troubles with getting chainingHints working. Sadly, there's no much information on the Internet about LanguageClient-neovim. Everyone on this planet seems to succumb either to VSCode or to coc.nvim. I refuse to use coc.nvim because I don't want to pollute my computer with JavaScript/node_modules/webdev crap just to get Rust autocompletion working.

Finally, it works. As you can see, I use next branch of LanguageClient-neovim: This is my ~/.config/nvim/settings.json:

{
    "rust-analyzer": {
        "checkOnSave": {
            "extraArgs": ["--target-dir", "/home/artur/.cache/rust-analyzer"]
        },
        "rustfmt": {
            "overrideCommand": ["rustfmt"]
        },
        "diagnostics": {
            "enable": true
        },
        "inlayHints": {
            "enable": true,
            "chainingHints": true,
            "typeHints": true,
            "parameterHints": true
        }
    }
}

And this is the part of ~/.config/nvim/init.vim which is reponsible for LanguageClient-neovim:

call plug#begin()
    Plug 'autozimu/LanguageClient-neovim', {
        \ 'branch': 'next',
        \ 'do': 'sh install.sh',
        \ }
    let g:LanguageClient_serverCommands = {
        \ 'rust': ['rust-analyzer'],
        \ 'c': ['clangd'],
        \ 'cpp': ['clangd'],
        \}
    let g:LanguageClient_settingsPath = expand('~/.config/nvim/settings.json')
    let g:LanguageClient_loggingFile = expand('~/.config/nvim/LanguageClient.log')
    let g:LanguageClient_loggingLevel = 'DEBUG'

P. S. Sorry if my comment offends JavaScript/webdev fans

[Logarithmus]

Are there any plans to implement something like this: https://github.com/fannheyward/coc-rust-analyzer/issues/394#issuecomment-742273063 Looks like a reasonable trade-off until https://github.com/neovim/neovim/pull/9496 is finished.

[martskins]

@Logarithmus that is actually what #1108 implements, unless I misunderstood what you meant. I think the issue you are having though is due to using an incorrect settings.json. Try changing rust-analyzer in the root of your settings.json to initializationOptions, if that doesn't work please open an issue and I can help you solve that.

[Logarithmus]

@Logarithmus that is actually what #1108 implements, unless I misunderstood what you meant. I think the issue you are having though is due to using an incorrect settings.json. Try changing rust-analyzer in the root of your settings.json to initializationOptions, if that doesn't work please open an issue and I can help you solve that.

I meant TypeHints & ParameterHints. Currently LanguageClient-neovim only supports displaying ChainingHints. In comparison, coc-rust-analyzer implements both ChainingHints & TypeHints: https://github.com/fannheyward/coc-rust-analyzer/issues/394#issuecomment-742273063. TypeHints which are located on the same line are joined into single hint and then displayed at the end of line.

[martskins]

Oh I see, I guess it would be a decent addition. I for one find it too distracting, but I guess it's a nice middleground for people that want that.