extern crate rand; // 0.6.4

use std::collections::HashMap;
use rand::Rng;
use std::sync::MutexGuard;




struct A<'a>(MutexGuard<'a, HashMap<i32, String>>, MutexGuard<'a, HashMap<String, Vec<u32>>>);

impl A<'_>{
    fn f(&mut self, i: i32) -> Option<&mut Vec<u32>>{
        if let Some(l) = self.0.get(&i){
            if let Some(e) = self.1.get_mut(l){
                return Some(e);
            }
        }

        None
    }
}



fn main() {
    let mut a = A( unsafe{ std::mem::uninitialized() }, unsafe{ std::mem::uninitialized() } );

    let mut rng = rand::thread_rng();

    let e = a.f(rng.gen());

    let f = a.f(rng.gen());

    println!("Hello, world!");
}