Cargo.toml

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

[profile.release]
opt-level = 3
debug = 2

main.rs

use std::{collections::HashMap, rc::Rc, time::Instant};

#[derive(Clone)]
pub enum WithMap {
    List(List<WithMap>),
    Map(Map<WithMap, WithMap>),
}

#[derive(Clone)]
pub enum NoMap {
    List(List<NoMap>),
}

#[derive(Clone)]
pub struct List<T>(pub Rc<Vec<T>>);

#[derive(Clone)]
pub struct Map<K, V>(pub HashMap<K, V>);

fn no_map() {
    let start = Instant::now();
    for _ in 0..2000 {
        let obj = NoMap::List(List(Rc::new(vec![])));
        for _ in 0..100000 {
            let _ = obj.clone();
        }
        let list = List::<NoMap>(Rc::new(vec![]));
        for _ in 0..100000 {
            let _ = list.clone();
        }
    }
    println!("no-map: {}ms", start.elapsed().as_millis());
}

fn with_map() {
    let start = Instant::now();
    for _ in 0..2000 {
        let obj = WithMap::List(List(Rc::new(vec![])));
        for _ in 0..100000 {
            let _ = obj.clone();
        }
        let list = List::<WithMap>(Rc::new(vec![]));
        for _ in 0..100000 {
            let _ = list.clone();
        }
    }
    println!("with-map: {}ms", start.elapsed().as_millis());
}
fn main() {
    no_map();
    with_map();
}