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Advanced 18 min readModule: Module 3: The Ownership Model & Move Semantics

The 3 Ownership Rules & Move Semantics

Master Rust's core breakthrough: Ownership rules, move semantics on heap data, and automatic Drop.

What You Will Learn in This Lesson

  • The 3 laws of Rust Ownership
  • How ownership transfers (Move semantics) prevent double-free bugs
  • Automatic memory deallocation when owners go out of scope (Drop trait)

Introduction & Core Concept

Ownership is Rust's most unique feature. It enables Rust to make memory safety guarantees without needing a garbage collector.
WHY DOES THIS MATTER IN THE REAL WORLD?

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

Ownership Move Semantics

rust
rust
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fn main() {
    let s1 = String::from("KWAS Academy");
    let s2 = s1; // Ownership MOVED to s2. s1 is no longer valid!
 
    println!("s2: {}", s2);
    // println!("s1: {}", s1); // Compile Error: value borrowed here after move!
}

Line-by-Line Technical Breakdown

1Stack-only types (like integers and floats) implement the Copy trait and are copied rather than moved.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[RUST]
RUST SOURCE EDITOR
Interactive Live Code

Industry Best Practices & Professional Standards

  • Embrace move semantics; use .clone() only when an explicit deep heap copy is truly required.

Lesson Summary & Core Takeaways

  • Ownership rules eliminate use-after-free and double-free bugs at compile time.