deref-coercions.md

% Deref coercions

There is a new edition of the book and this is an old link.

Implementing the Deref trait allows us to customize the behavior of the dereference operator *. By implementing Deref in such a way that a smart pointer can be treated like a regular reference, we can write code that operates on references and use that code with smart pointers too.

use std::ops::Deref;

# struct MyBox<T>(T);
impl<T> Deref for MyBox<T> {
    type Target = T;

    fn deref(&self) -> &T {
        &self.0
    }
}

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Here are the relevant sections in the new and old books:

• in the current edition: Ch 15.02 — Treating Smart Pointers like Regular References with the Deref Trait
• In the first edition: Ch 3.33 — Deref coercions