Formatting float ranges may result in invalid code

[ur-fault]

Formatting float ranges with lower bound specified without decimal part leads to invalid Rust code.

Summary

I tried to format this code:

fn main() {
    let x = 0.5;

    match x {
        1. .. => println!("{x} >= 1"),
        _ => println!("{x} < 1"),
    }
}

Expected behavior

Nothing to happen, since the code is already formatted correctly.

Actual behavior

rustfmt formatted 1. .. as 1....

Configuration

Just default options.

Reproduction Steps

Just format the code.

Meta

rustfmt --version:

rustfmt 1.9.0-nightly (7af3402cda 2026-04-16)