When supressing possibly-uninitialized errors, prefer showing the textually earlier error

[CAD97]

I tried this code:

pub fn transliterate(mut origin: String) -> String {
    let counter: usize = origin.chars().count();
    let mut j: usize = 0;
    let mut i: usize = 0;
    let origin_vec: Vec<char> = origin.chars().collect();
    let mut origin_mutated: Vec<char>;
    if j <= counter {
        while j <= counter {
            match origin_vec[j] {
                'А' => {
                    origin_mutated[i] = 'A';
                    i += 1;
                    j += 1;
                }
                // snip
                'Я' => {
                    origin_mutated[i] = 'Y';
                    i += 1;
                    j += 1;
                    origin_mutated[i] = 'a';
                    i += 1;
                }
                _ => {
                    j += 1;
                }
            }
        }
    } else if j > counter {
        origin_mutated[i] = '\n';
    } else {
        origin = origin_mutated.into_iter().collect();
    }
    //origin = origin_mutated.into_iter().collect();
    (origin)
}

I expected to see this happen: the possibly-uninitialized error would report the textually first usage of origin_mutated

error[E0381]: borrow of possibly-uninitialized variable: `origin_mutated`
  --> src/lib.rs:11:21
   |
11 |                     origin_mutated[i] = 'A';
   |                     ^^^^^^^^^^^^^^ use of possibly-uninitialized `origin_mutated`

Instead, this happened: the possibly-uninitialized error reports the textually last usage of origin_mutated

error[E0381]: borrow of possibly-uninitialized variable: `origin_mutated`
   --> src/lib.rs:188:21
    |
188 |                     origin_mutated[i] = 'Y';
    |                     ^^^^^^^^^^^^^^ use of possibly-uninitialized `origin_mutated`

Originally reported by L0uisc on irlo.

@rustbot modify labels: +A-diagnostics, +D-papercut

[estebank]

Current output:

error[[E0381]](https://doc.rust-lang.org/nightly/error_codes/E0381.html): used binding `origin_mutated` isn't initialized
   --> src/lib.rs:202:18
    |
6   |     let mut origin_mutated: Vec<char>;
    |         ------------------ binding declared here but left uninitialized
...
202 |         origin = origin_mutated.into_iter().collect();
    |                  ^^^^^^^^^^^^^^ `origin_mutated` used here but it isn't initialized
    |
help: consider assigning a value
    |
6   |     let mut origin_mutated: Vec<char> = vec![];
    |                                       ++++++++

[CAD97]

This is definitely an improvement, but I still think it's important the textually first usage gets blamed. The original user was confused because they assumed that the other usages which weren't warned about were a) not cause for an error and b) initializing the binding.