Failed optimization: missing range/enumerate bijection suppresses length fact propagation

[SUPERCILEX]

pub fn score_round_opt(candidates: &[bool]) {
    u32::try_from(candidates.len()).unwrap();

    for (i, _) in candidates.iter().enumerate() {
        u32::try_from(i).unwrap();
        std::hint::black_box(42);
    }
}

pub fn score_round_fail(candidates: &[bool]) {
    u32::try_from(candidates.len()).unwrap();

    for i in 0..candidates.len() {
        u32::try_from(i).unwrap();
        std::hint::black_box(42);
    }
}

https://rust.godbolt.org/z/8a6jd8acG

The unwrap in the loop fails to get optimized out when using 0..candidates.len() even though this is equivalent to enumerate.

[LingMan]

Optimizes as expected since Rust 1.73.

[nikic]

Closing this per previous comment. I expect that the root cause here is the same as #92174, so adding a test for that one should be sufficient.

Oops, I misread this (enumerate was working, manual iteration wasn't). Keeping this open with E-needs-test.