Option variable is not checked correctly

Code

fn main() -> Result<(), Box<dyn Error>> {
    
    let mut array = vec![String::from("jaja"), String::from("haha"), String::from("fafa")];

    let mut data_ptr: Option<&mut String> = None;

    let mut count = 100;
    while count > 0 {
         if data_ptr.is_none(){
            data_ptr = None;
            for item in array.iter_mut(){      
                if item .starts_with("f"){
                    data_ptr = Some(item);
                    break;
                }
            }
         
        }
        // .....
        if data_ptr.is_some(){
            println!("find {:?}", data_ptr);
            data_ptr = None;         
        }

        count -= 1;
    }
    Ok(())
}

Current output

if data_ptr.is_none(){
   |             -------- first borrow used here, in later iteration of loop
17 |             // data_ptr = None;
18 |             for item in array.iter_mut(){
   |                         ^^^^^ `array` was mutably borrowed here in the previous iteration of the loop

Desired output

it is None already, it has been checked by "data_ptr.is_none()". we have to bind it to None again to tell rustc, it is None.

Rationale and extra context

No response

Other cases

// data_ptr = None; 

mask this line, evertything is ok

Rust Version

rustc 1.93.0 (254b59607 2026-01-19)
binary: rustc
commit-hash: 254b59607d4417e9dffbc307138ae5c86280fe4c
commit-date: 2026-01-19
host: x86_64-pc-windows-msvc
release: 1.93.0
LLVM version: 21.1.8

Anything else?

No response

Reproduce the supplied example with rustc 1.93.0 and compare the diagnostic with the reported current and desired output. Investigate the compiler's borrow-checking and diagnostic behavior for the mutable reference stored in Option; done means the issue is either explained with a precise limitation or the reported case receives an appropriate diagnostic change.