#![feature(nll)]

use std::result;

#[derive(Debug)]
pub struct Error<'a>(&'a u8);

pub type Result<'a, T> = result::Result<T, Error<'a>>;
pub struct Context;

impl Context {
    pub fn open<'a>(&'a mut self) -> Result<'a, ()> {
        Err(Error(&0))
    }

    pub fn close<'a>(&'a self) -> Result<'a, ()> {
        Err(Error(&0))
    }
}

fn bar(ctx : &mut Context) -> Result<()> {
    match ctx.open() { Err(e) => return Err(e), Ok(x) => x };
    let _ = ctx.close();
    Ok(())
}

fn main() {
    let mut ctx = Context;
    let res = bar(&mut ctx).unwrap_err();
    println!("{:?}",res);
}