"Rust Analyzer is not found", with correct minimal coc-settings.json

Env:

• macOS 10.15.4
• nvim v0.5.0-503-g9816173fb, also tried 0.4.3 stable from homebrew, same issue.
• coc.nvim release branch
• rust-analyzer compiled myself and located at $HOME/bin
• I have a relatively minimal init.vim

coc-settings.json:

{
    "rust-analyzer.serverPath": "/Users/damien/bin/rust-analyzer"
}

The rust-analyzer plugin does not seem to be reading the settings file correctly. Each time I open a Rust file, I am prompted with:

Rust Analyzer is not found, download from GitHub release?:
1. Yes
2. Cancel
Type number and <Enter> or click with mouse (empty cancels):

If I pick 1, a new binary is downloaded, but the plugin never launches. Autocomplete, gd, etc. all do not work. Tailing the output of a logging wrapper (thanks @burntsushi) aroundrust-analyzer shows it is never called by the plugin.

Am I missing anything? How can I better debug why the plugin doesn’t respect the coc-settings config?

[rsignavong]

It works for me. I’ve cloned the rust-analyzer’s repository and then switch to release branch, then I build it with cd ~/LanguageServers/rust-analyzer && cargo xtask install --server. I see the rust-analyzer binary inside ~/.cargo/bin

Then my :CocConfig is just this.

{
  "coc.preferences.formatOnSaveFiletypes": [
    ...
    "rust",
    ...
  ],
  "diagnostic.errorSign": "✘",
  "diagnostic.infoSign": "i",
  "languageserver": {
    ...
    "rust": {
      "command": "rust-analyzer",
      "filetypes": ["rust"],
      "rootPatterns": ["Cargo.toml"]
    }
  }
}

Then when I open a Rust file, it loads the rust-analyzer. Sometimes, it asks to install the Rust-analyzer, and I answer 1. Yes but I don’t know if it does something different.

[semanser]

I had the same issue. This coc-settings.json works for me:

"languageserver": {
    "rust": {
      "command": "rust-analyzer",
      "filetypes": ["rust"],
      "rootPatterns": ["Cargo.toml"]
    }
  }