Rustacean

 Rust (programming language) - Wikipedia

Copilot:

Yes, Qiskit has indeed adopted Rust as part of its development. While Qiskit’s primary language is Python, certain computationally intensive internals were re-implemented in Rust for performance reasons. Rust provides a balance between speed and safety, giving Qiskit developers the best of both worlds1. Additionally, Rust is also used in other areas related to quantum computing, such as the rustworkx library, which leverages Rust’s inherent performance and safety2. 😊

Simple, and powerful:

Variables are immutable by default, and adding the mut keyword allows the variable to be mutated.^[39] The following example uses //, which denotes the start of a comment.^[40]

fn main() {
    let mut foo = 10; // This code would not compile without adding "mut".
    println!("The value of foo is {foo}");
    foo = 20;
    println!("The value of foo is {foo}");
}