Use "Configuring Rustfmt" with rust-analyzer on VS Code

[mirumirumi]

Hi!
I use rust-analyzer to fomat the code when saving (editor.formatOnSave).
I want to customize the format to this format, so I figured I could apply the config here (https://rust-lang.github.io/rustfmt).

So I have tried the following settings in settings.json with various patterns, but it does not work fine.

{
    "[rust]": {
        "editor.formatOnSave": true,
    },
      "rust-analyzer.rustfmt.extraArgs": [
        "blank_lines_upper_bound = 999",
        "imports_layout = \"HorizontalVertical\"",
        "imports_granularity = \"Crate\"",
        "overflow_delimited_expr = true",
        "group_imports = \"StdExternalCrate\"",
        "struct_lit_single_line = false",
    ],
}

And the trouble is, it seems that it only knows that I am trying to define an entry rust-analyzer.rustfmt.extraArgs, so the contents of the config are not reflected, and the code formatting function itself stops working.

What should I do?

[lnicola]

Can you use a rustfmt.toml? The right syntax for rust-analyzer.rustfmt.extraArgs is probably ["--config", "blank_lines_upper_bound=999,overflow_delimited_expr=true"].

[mirumirumi]

Thanks for the response!

After much experimentation based on the advice I received, I found that I should not put spaces in the middle or escape ".
The following code is it works :)

    "rust-analyzer.rustfmt.extraArgs": [
        "--config", "blank_lines_upper_bound=999,imports_layout=HorizontalVertical,imports_granularity=Crate,overflow_delimited_expr=true,group_imports=StdExternalCrate,struct_lit_single_line=false",
    ],

[lnicola]

I'd still suggest using a rustfmt.toml file instead.

[nulliver]

I know this is old but I also wanted to pass extra arguments to rustfmt and I wanted to use the rustfmt.toml file. I had some troubles making it work but what worked in the end was this:

I saved the rustfmt config file in ~/.config/rustfmt/rustfmt.toml

tab_spaces = 2

In Zed's settings, I added this:

"lsp": {
    "rust-analyzer": {
      "initialization_options": {
        "rustfmt": {
          "extraArgs": ["--config-path", "/Users/<your_user>/.config/rustfmt"]
        }
      }
    }
  }

Notice that in the configuration I had to use the absolute path to the rustfmt.toml file, I couldn't make it work with $HOME or ~ in the path to refer to my home directory.

[lnicola]

@nulliver according to https://rust-lang.github.io/rustfmt/ and https://docs.rs/dirs/latest/dirs/fn.config_dir.html, if you put it under ~/Library/Application Support, you won't have to pass the path in the command line.

[nulliver]

@lnicola I tried that first and it didn't work but now that I got it working with the extraArgs configuration, I removed that configuration and moved the rustftm.toml file to ~/Library/Application Support/rustfmt/ and this time it worked! I guess I was doing something wrong the first time.

Thank you.