My rustfmt Settings

May 2025

First Off...

rustfmt is a tool to format Rust files.

There's a ton of info on that page about the tool. None of it is about configuration. You gotta go to the Configuring Rustfmt page to get those details.

Everything, Or Not

You can make a global config file for rustfmt by dropping a file in your home directory at:

~/.rustfmt.toml

Using different options for a specific project is done by putting a .rustfmt.toml file in the directory that hold your Cargo.toml file.

It probably makes sense to do that if you do any collaboration with other folks. That way everyone's working with the same settings.

Make It Look Like This

This is what I've set up in my rust formatter file:

file: ~/.rustfmt.toml

fn_params_layout = "Vertical"
max_width = 56
newline_style = "Unix"
tab_spaces = 2

More To Come

There's some other cool stuff working its way into the formatter. These are currently unstable. Once they move into the stable branch I'll be playing around with these:

brace_style = "PreferSameLine"
empty_item_single_line = false
enum_discrim_align_threshold = 20
force_multiline_blocks = true

There's also specific style guides. Probably makes sense to look at those for collaborative efforts. Takes the conflicts from differing opinions out of the mix.

-a

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Endnotes

You can also name the config files without that dot:

rustfmt.toml

Instead of with it:

config

.rustfmt.toml