How to Convert Between Struct Types in Rust (From/Into)

Implement the From trait on the source struct to define the conversion logic, then use the .into() method on the source instance to convert it to the target type. This approach leverages Rust's standard conversion traits to handle type casting cleanly without manual field-by-field copying.

struct Point {
    x: i32,
    y: i32,
}

struct Point2D {
    x: i32,
    y: i32,
}

impl From<Point> for Point2D {
    fn from(point: Point) -> Self {
        Point2D { x: point.x, y: point.y }
    }
}

fn main() {
    let p = Point { x: 10, y: 20 };
    let p2d: Point2D = p.into();
}

The From trait tells Rust exactly how to turn one type of data into another, while Into is the automatic shortcut that uses those rules. Think of it like a universal adapter: you define the shape of the plug once (From), and then you can plug any compatible device into any socket (Into) without worrying about the details. You use this whenever you need to swap data formats between your custom structures.