Incorrect 'before the previous value is read' rustc warning on +=

Code

fn sum_options(items: Vec<Option<u32>>) {
    let mut total = 0;
    for item in items {
        match item {
            Some(val) => total += val,
            None => total += 1,
        }
    }

    // println!("{}", total);
}

Current output

warning: value assigned to `total` is never read
 --> src/main.rs:5:26
  |
5 |             Some(val) => total += val,
  |                          ^^^^^^^^^^^^ this value is reassigned later and never used
6 |             None => total += 1,
  |                     ---------- `total` is overwritten here before the previous value is read
  |
  = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default

Desired output

warning: value assigned to `total` is never read
 --> src/main.rs:5:26
  |
5 |             Some(val) => total += val,
  |                          ^^^^^^^^^^^^ this value is reassigned later and never used
6 |             None => total += 1,
  |                     ---------- this value is reassigned later and never used
  |
  = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default

Rationale and extra context

"total is overwritten here before the previous value is read" makes no sense here: since I'm using +=, it's always read, although the variable is never used after the loop.

I'm not sure what the best error phrasing is here, but unless I'm missing something obvious the current wording is wrong.

Rust Version

$ rustc --version --verbose
rustc 1.96.0 (ac68faa20 2026-05-25)
binary: rustc
commit-hash: ac68faa20c58cbccd01ee7208bf3b6e93a7d7f96
commit-date: 2026-05-25
host: x86_64-unknown-linux-gnu
release: 1.96.0
LLVM version: 22.1.2