identity_op: span could point at the redundant expression instead of the rest of it?

Description

fn main() {
    let _ =  (1 + 2) * 1 - 1;
}

warning:

warning: this operation has no effect
 --> src/main.rs:2:14
  |
2 |     let _ =  (1 + 2) * 1 - 1;
  |              ^^^^^^^^^^^ help: consider reducing it to: `(1 + 2)`
  |
  = note: `#[warn(clippy::identity_op)]` on by default
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#identity_op

it's a bit weird that clippy says "this operation has no effect" and then underlines everything BUT the operation that has no effect... 😅

would it make sense to underline the * 1 instead?

Perhaps this newer fancier diff-like diagnostic format could be used here?

-    let _ =  (1 + 2) * 1 - 1;
                      ~~~  // this part ^ would be red
+   let _ =  (1 + 2)      - 1;

Version

clippy 0.1.65 (3f83906 2022-09-24)

Additional Labels

No response

Start at the identity_op lint entry point and reproduce the diagnostic with the Rust example in this issue. Adjust the reported span so it highlights the redundant * 1 operation rather than the surrounding expression, then verify that the warning and suggested reduction use the intended range.