“borrowed value does not live long enough” when using as_slice()

Question

I ran into an error:

extern crate rustc_serialize; // 0.3.24

use rustc_serialize::base64::{self, FromBase64, ToBase64};

fn main() {
    let a: [u8; 30] = [         


        

Answer 1

The problem here is that you are not storing the result of from_base64 anywhere and then take a reference to it by calling as_slice. Chaining calls like that causes the result of from_base64 to go out of scope at the end of the line and the reference taken is no longer valid.

extern crate rustc_serialize; // 0.3.24

use rustc_serialize::base64::FromBase64;

fn main() {
    let a: [u8; 30] = [0; 30];
    let b = a.from_base64().unwrap();
    println!("{:?}", b.as_slice());
}