trpl-zh-cn/listings/ch13-functional-features/listing-13-05/src/main.rs

fn main() {
    let mut list = vec![1, 2, 3];
    println!("Before defining closure: {:?}", list);

    let mut borrows_mutably = || list.push(7);

    borrows_mutably();
    println!("After calling closure: {:?}", list);
}