fix(formatter): sort use self::... items by their full path compare_names("self", "self") returned Greater, violating sort reflexivity. Multiple use self::x; statements were therefore ordered only on the leading self segment and never recursed t - #10018

Summary

Fixes a bug in compare_names where "self" compared against itself did not return Ordering::Equal, causing use self::* imports to not be sorted correctly among themselves.

Type of change

Please check one:

• Bug fix (fixes incorrect behavior)
• New feature
• Performance improvement
• Documentation change with concrete technical impact
• Style, wording, formatting, or typo-only change

Why is this change needed?

The compare_names function handled "self" in ordering rules relative to other keywords (super, crate) but was missing an explicit case for ("self", "self"). Without it, the comparison fell through to the catch-all rules, which could produce an incorrect ordering (e.g., Ordering::Greater instead of Ordering::Equal), preventing use self::* imports from being sorted alphabetically.

What was the behavior or documentation before?

Multiple use self::* imports were not sorted correctly by the formatter. For example:

use self::e;
use self::c;
use self::a;
use self::d;
use self::b;

would not be reordered.

What is the behavior or documentation after?

use self::* imports are now sorted alphabetically:

use self::a;
use self::b;
use self::c;
use self::d;
use self::e;

Related issue or discussion (if any)

N/A

Additional context

A new test case (sort_self_use) was added with input and expected output files to cover this scenario.