What is the Deref trait

The Deref trait allows custom smart pointer types to be treated like regular references by defining how to access the inner data. Implementing Deref enables dereferencing coercion, letting you call methods on the inner value directly without manual dereferencing.

use std::ops::Deref;

struct MyBox<T>(T);

impl<T> Deref for MyBox<T> {
    type Target = T;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

fn main() {
    let x = MyBox(5);
    println!("{}", *x); // Works because of Deref
}

The Deref trait lets you treat a custom wrapper type exactly like the data it holds. It acts like a universal adapter, allowing you to access the inner value without writing extra code to unwrap it every time. Think of it as a key that automatically unlocks a box so you can use the item inside as if it were sitting on the table.