Do tuples implement `Copy`?

Question

In the Rust Book, Chapter 18, they give an example of a tuple in pattern matching.

fn print_coordinates(&(x, y): &(i32, i32)) {
    println!("Current location: ({}, {})", x, y);
}

fn main() {
    let point = (3, 5);
    print_coordinates(&point);   // point passed as reference
}

Out of curiosity, I tried without passing as a reference like this.

fn print_coordinates((x, y): (i32, i32)) {
    println!("Current location: ({}, {})", x, y);
}

fn main() {
    let point = (3, 5);
    print_coordinates(point);   // point passed as value
    print_coordinates(point);   // point is still valid here
}

It compiles and prints out the coordinates 2 times.

Can tuples be passed into functions just like other primitive data types (numbers, booleans, etc.)?

Answer 1

Yes; according to the docs, this is true for tuples of arity 12 or less:

If every type inside a tuple implements one of the following traits, then a tuple itself also implements it.

• Clone
• Copy
• PartialEq
• Eq
• PartialOrd
• Ord
• Debug
• Default
• Hash

Due to a temporary restriction in Rust's type system, these traits are only implemented on tuples of arity 12 or less. In the future, this may change.