What's the output of :CocInfo

    3 vim version: NVIM v0.8.1
    4 node version: v18.12.1
    5 coc.nvim version: 0.0.82-b7375d5f 2023-01-30 05:09:03 +0800
    6 coc.nvim directory: /home/bombela/.config/nvim/plugged/coc.nvim
    7 term: xterm-256color
    8 platform: linux

What's the output of :CocCommand rust-analyzer.serverVersion

[coc.nvim] rust-analyzer 0.4.1442-standalone

What's your coc-rust-analyzer version? You can get it from :CocList extensions

coc-rust-analyzer 0.72.1

In my coc-config I also have:

    3   "rust-analyzer.updates.checkOnStartup": "false",
    4   "rust-analyzer.rustfmt.enableRangeFormatting": true,
    5   "rust-analyzer.updates.channel": "nightly",

And :echo CocHasProvider('formatRange') returns v:true.

(by the way, "rust-analyzer.rustfmt.enableRangeFormatting": true enables the feature but "rust-analyzer": { "rustfmt.enableRangeFormatting": true } does not. Took me 45minutes to realize that).

Then I do :set formatexpr=CocAction('formatSelected'). Now I expect gq on a visual selection to format similar to RustFmt. Instead it formats the same as the default vim behavior. :CoInfo reports nothing of interest besides Request action: formatSelected [].

As a baseline, I can compare with rustfmt nightly and :'<,'>RustFmtRange.

Just to make sure things are happening at all, I can :set formatexpr=CocAction('wontwork'), and in this case it silently doesn't format anything. And :CoInfo reports Request error: wontwork [] Error: Action "wontwork" not exist.

I can also :set formatexpr=CocAction('format'), which does indeed format the whole file like RustFmt, confirming again that something is really executed.

So it appears that CocAction('formatSelected') with coc-rust-analyzer somehow falls-back to the default neovim formatting. I am not sure how to debug the issue further.