use std::collections::HashMap;
use std::hash::Hash;

fn source<K, V>(_key: K) -> V {
    unimplemented!()
}

fn get_foo(vec: Vec<&str>) -> HashMap<String, usize> {
    vec.into_iter().map(|k| (k.to_owned(), source(k))).collect()
}

fn get_bar<K, V>(vec: Vec<&K>) -> HashMap<K, V>
where
    K: Eq + Hash + Clone,
{
    vec.into_iter().map(|k| (k.clone(), source(k))).collect()
}

fn main() {
    let num: Vec<String> = ["1","2","3"].iter().map(|&s| s.to_owned()).collect();
    let vec: Vec<&str> = num.iter().map(|s| s.as_str()).collect();
    let map: HashMap<String, usize> = get_bar(vec);
}