Unsafe Traits

Define and implement unsafe traits.

Difficulty

Advanced

Code

unsafe trait Dangerous {
    fn dangerous_method(&self);
}

struct MyType {
    value: i32,
}

unsafe impl Dangerous for MyType {
    fn dangerous_method(&self) {
        println!("calling dangerous method on {}", self.value);
    }
}

fn take_dangerous<T: Dangerous>(item: &T) {
    item.dangerous_method();
}

fn main() {
    let x = MyType { value: 42 };
    take_dangerous(&x);
}

Explanation

Unsafe traits have invariants the compiler cannot verify.

Key Concepts

• Read the code carefully and understand the data flow
• Try modifying the example to see how it changes behavior
• Run this code in the Rust Playground

Related Topics

Browse more examples in the unsafe category to build a complete understanding of this topic.