Rust Edition Guide は現在 Rust 2024 のアップデート作業に向けて翻訳作業中です。本ページはある時点での英語版をコピーしていますが、一部のリンクが動作しない場合や、最新情報が更新されていない場合があります。問題が発生した場合は、原文（英語版）をご参照ください。

Rustfmt: Version sorting

Summary

rustfmt utilizes a new sorting algorithm.

Details

The Rust Style Guide includes rules for sorting that rustfmt applies in various contexts, such as on imports.

Previous versions of the Style Guide and Rustfmt generally used an "ASCIIbetical" based approach. In the 2024 Edition this is changed to use a version-sort like algorithm that compares Unicode characters lexicographically and provides better results in ASCII digit comparisons.

For example with a given (unsorted) input:

use std::num::{NonZeroU32, NonZeroU16, NonZeroU8, NonZeroU64};
use std::io::{Write, Read, stdout, self};

In the prior Editions, rustfmt would have produced:

use std::io::{self, stdout, Read, Write};
use std::num::{NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8};

In the 2024 Edition, rustfmt now produces:

use std::io::{self, Read, Write, stdout};
use std::num::{NonZeroU8, NonZeroU16, NonZeroU32, NonZeroU64};

Migration

The change can be applied automatically by running cargo fmt or rustfmt with the 2024 Edition. See the Style edition chapter for more information on migrating and how style editions work.