结构体
结构体中生命周期的注解也类似于函数
// A type `Borrowed` which houses a reference to an // `i32`. The reference to `i32` must outlive `Borrowed`. #[derive(Debug)] struct Borrowed<'a>(&'a i32); // Similarly, both references here must outlive this structure. #[derive(Debug)] struct NamedBorrowed<'a> { x: &'a i32, y: &'a i32, } // An enum which is either an `i32` or a reference to one. #[derive(Debug)] enum Either<'a> { Num(i32), Ref(&'a i32), } fn main() { let x = 18; let y = 15; let single = Borrowed(&x); let double = NamedBorrowed { x: &x, y: &y }; let reference = Either::Ref(&x); let number = Either::Num(y); println!("x is borrowed in {:?}", single); println!("x and y are borrowed in {:?}", double); println!("x is borrowed in {:?}", reference); println!("y is *not* borrowed in {:?}", number); }