Shared via Rust Playground

playground.rs

use std::io;
use std::io::prelude::*;
use std::io::BufReader;
use std::fs::File;

fn get_line_vec(filename: &str) -> Result<&mut Vec<String>, io::Error> {
	let mut vec: Vec<String> = Vec::new();
	let mut f = try!(File::open(filename));
	BufReader::new(f).lines()
	    .map(|line| vec.push(line.unwrap()));
	Ok(&mut vec)
}

fn main(){
    match get_line_vec("yay.txt") {
        Ok(vec) => {
            let a = vec.pop().unwrap();
            println!("{}", a);
        },
        Err(e) => {
            println!("Error: {}", e.to_string())
        }
    }
}

SUCESS.rs

use std::io;
use std::io::prelude::*;
use std::io::BufReader;
use std::fs::File;

fn main(){
    match get_line_vec("yay.txt") {
        Ok(vec) => {
            let mut mut_vec = vec;
            let a = mut_vec.pop().unwrap();
            println!("{}", a);
        },
        Err(e) => {
            println!("Error: {}", e.to_string())
        }
    }
}

fn get_line_vec(filename: &str) -> Result<Vec<String>, io::Error> {
	let f = try!(File::open(filename));
	let vec: Vec<String> = BufReader::new(f).lines()
	    .map(|line| line.unwrap())
	    .collect();
	Ok(vec)
}

:11:10: 11:13 error: vec does not live long enough
:11 Ok(&mut vec)
^~~
:6:72: 12:2 note: reference must be valid for the anonymous lifetime #1 defined on the block at 6:71...
: 6 fn get_line_vec(filename: &str) -> Result<&mut Vec, io::Error> {
: 7 let mut vec: Vec = Vec::new();
: 8 let mut f = try!(File::open(filename));
: 9 BufReader::new(f).lines()
:10 .map(|line| vec.push(line.unwrap()));
:11 Ok(&mut vec)
...
:7:40: 12:2 note: ...but borrowed value is only valid for the block suffix following statement 0 at 7:39
: 7 let mut vec: Vec = Vec::new();
: 8 let mut f = try!(File::open(filename));
: 9 BufReader::new(f).lines()
:10 .map(|line| vec.push(line.unwrap()));
:11 Ok(&mut vec)
:12 }
error: aborting due to previous error
playpen: application terminated with error code 101