shadow_unrelated incorrectly flags a destructuring assignment

[Kromey]

Summary

Clippy appears to incorrectly flag the second variable in a destructuring assignment as shadowing the first, even when the two variables are different.

I do not see this behavior with a destructuring let binding, even when they do shadow other variables.

Lint Name

shadow_unrelated

Reproducer

I tried this code:

#![warn(clippy::shadow_unrelated)]

fn recompute(a: u32, b: u32) -> (u32, u32) {
    (a * 2, b * 4)
}

fn main() {
    let (mut start, mut end) = (12, 15);
    println!("{start}, {end}");
    (start, end) = recompute(start, end); // Lint flags this line
    println!("{start}, {end}");
}

I saw this happen:

warning: `end` shadows a previous, unrelated binding
  --> src/main.rs:10:13
   |
10 |     (start, end) = recompute(start, end);
   |             ^^^
   |
note: previous binding is here
  --> src/main.rs:10:6
   |
10 |     (start, end) = recompute(start, end);
   |      ^^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#shadow_unrelated

I expected to see this happen:
No warnings should appear

Additional note:
If I change the flagged line to let (start, end) = ... (and remove the now-unnecessary muts), clippy is happy even though both start and end are indeed being shadowed (albeit not unrelated). So the issue seems to be related specifically to this destructuring assignment.

Version

rustc 1.67.0 (fc594f156 2023-01-24)
binary: rustc
commit-hash: fc594f15669680fa70d255faec3ca3fb507c3405
commit-date: 2023-01-24
host: x86_64-unknown-linux-gnu
release: 1.67.0
LLVM version: 15.0.6

Additional Labels

No response

[Rudxain]

I have the same problem with this

const fn gcd(mut a: i128, mut b: i128) -> i128 {
	while b != 0 {
		(a, b) = (b, a % b);
	}
	a
}

I find it weird that something so simple doesn't seem to be covered by tests (I haven't read the tests in this repo, so don't take me seriously)

[matte1]

I hit this as well!

[QTi1]

Here's another example without anything mutable:

#![warn(clippy::shadow_unrelated)]
fn main() {
    let (zero, one);
    (zero, one) = (0, 1); // Lint flags this line
    println!("{zero}, {one}");
}

[GitPinkRabbit]

+1, hope to fix. Considering #13795 is fixed.