//#![feature(nll)]

use std::marker::PhantomData;

struct Handler<'a> {
    _marker: PhantomData<&'a u32>,
}

impl<'a> Handler<'a> {
    pub fn on_change<T>(&self, data: &'a mut T)
    where T: 'a,
    {
        println!("{:?}", data as *mut _)
    }
}

fn main() {
    //let mut foo = 1; // this line should be valid
    let handler = Handler { _marker: PhantomData };
    {
        let mut foo = 1; // this line should be illegal
        handler.on_change(&mut foo);
    }
}