Rust macro for hashmap

macro.rs

use std::collections::HashMap;

#[macro_export]
macro_rules! map (
    {$($key:expr => $value:expr), + } => {
        {
            let mut m = HashMap::new();
            $(
                m.insert($key, $value);
             )+
            m
        }
    };
);

pub fn abc() {
  let numbers = map!{ 1 => "one", 2 => "two" };
}