let list = vec![1, 2, 3]; println!("Before defining closure: {list:?}"); let only_borrows = || println!("From closure: {list:?}"); println!("Before calling closure: {list:?}"); only_borrows(); [unoptimized + debuginfo] target(s) in 0.43s Running `target/debug/closure-example` Before defining closure: [1, 2, 3] Before calling closure: [1, 2, 3] From closure: [1, 2, 3] After calling closure: [1, 2 增加一个元素。闭包现在捕获一 个可变引用： 文件名：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();