Incorrect "unused variable" warning

Code

pub struct Test {
    records: [TestRecord; 5],
}

#[derive(Clone,Copy)]
struct TestRecord {
    flag: bool,
}

impl TestRecord {
    pub fn new() -> TestRecord {
        TestRecord { flag: false }
    }
}

impl Test {
    pub fn new() -> Test {
        let records = [TestRecord::new(); 5];
        Test { records }
    }
}

fn main() {
    let mut e = Test::new();
    for mut r in e. records {
        r. flag = true;
        print!( "+" );
    }
    println!("");

    // The following equivalent gives no warning.
    e. records. iter_mut(). for_each( |r| { r. flag = true; print!( "*" ); } );
    println!("");
}

Current output

Compiling playground v0.0.1 (/playground)
warning: unused variable: `r`
  --> src/main.rs:26:9
   |
26 |     for mut r in e. records {
   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_r`
   |
   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default

warning: `playground` (bin "playground") generated 1 warning (run `cargo fix --bin "playground" -p playground` to apply 1 suggestion)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.70s
     Running `target/debug/playground`

Desired output

Compiling playground v0.0.1 (/playground)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.75s

Rationale and extra context

No response

Other cases

Rust Version

rustc 1.93.1 (01f6ddf75 2026-02-11)
binary: rustc
commit-hash: 01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf
commit-date: 2026-02-11
host: x86_64-apple-darwin
release: 1.93.1
LLVM version: 21.1.8

Anything else?

No response