unchecked_duration_subtraction fix doesn't account for order of operations

Summary

The fix for unchecked_duration_subtraction doesn't correctly account for order of operations in expressions it fixes resulting in regressions in the code.

Reproducer

Given this program

use std::time::{Duration, Instant};

fn main() {
    let x = Duration::from_millis(10);
    let y = Duration::from_millis(50);
    let start = Instant::now();
    let i = 50;

    let result = start + i * x - y;
    let relative = result - start;
    assert_eq!(relative.as_millis(), 450);
}

Running cargo clippy --fix results in:

use std::time::{Duration, Instant};

fn main() {
    let x = Duration::from_millis(10);
    let y = Duration::from_millis(50);
    let start = Instant::now();
    let i = 50;

    let result = start + i * x.checked_sub(y).unwrap();
    let relative = result - start;
    assert_eq!(relative.as_millis(), 450);
}

Here the order of operations have changed from (i * x) - y to i * (x - y).

See full run here:

Version

rustc 1.67.0 (fc594f156 2023-01-24)
binary: rustc
commit-hash: fc594f15669680fa70d255faec3ca3fb507c3405
commit-date: 2023-01-24
host: aarch64-apple-darwin
release: 1.67.0
LLVM version: 15.0.6

Additional Labels

No response

Start by locating the unchecked_duration_subtraction lint and reproduce the issue with the supplied Rust program and cargo clippy --fix. Verify that the fix preserves the original order of operations, keeping (i * x) - y distinct from i * (x - y), and confirm the corrected output no longer changes the program's result.