Ownership, Borrowing & Lifetimes in Practice

The Borrow Checker Mental Model

Rust replaces garbage collection and manual memory management with a single compile-time invariant:

1. Each value in Rust has an owner.
2. There can only be one owner at a time.
3. When the owner goes out of scope, the value is dropped.

Aliasing XOR Mutability

You may have either:

• Any number of immutable references (&T), OR
• Exactly one mutable reference (&mut T).