Simple rust wordle solver

Cargo.toml

[package]
name = "wobli"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]

main.rs

use std::fs::File;
use std::io::{prelude::*, BufReader};

const NULL_CHAR: char = '\0';

static LETTERS: &[char] = &['m', 'o'];
static POS_LETTERS: &[char] = &[NULL_CHAR, NULL_CHAR, 'm', NULL_CHAR, NULL_CHAR];
static NOT_POS: &[&[char]] = &[&[], &['o'], &[], &[], &[]];


fn main() {
    let file = File::open("/usr/share/dict/words").unwrap();
    let reader = BufReader::new(file);

    let mut counter: u64 = 0;

    'outer: for line in reader.lines() {
        let line = line.unwrap();
        if line.len() != 5 {
            continue;
        }

        for ch in LETTERS {
            if line.contains(*ch) {
                continue
            } else {
                continue 'outer;
            }
        }

        for (pch, ch) in POS_LETTERS.iter().zip(line.chars()) {
            if *pch == NULL_CHAR {
                continue
            }

            if *pch != ch {
                continue 'outer;
            }
        }

        for (list_ch, ch) in NOT_POS.iter().zip(line.chars()) {
            for not_ch in *list_ch {
                if ch == *not_ch {
                    continue 'outer;
                }
            }
        }

        counter+=1;

        println!("{}", line);

    }
    println!("{}", counter);
}