#![feature(pin, arbitrary_self_types, optin_builtin_traits)]

use std::marker::Unpin;
use std::mem::PinMut;

struct SelfReferential {
    foo_ptr: *const u8,
    x: u8,
}

impl !Unpin for SelfReferential {}

impl SelfReferential {
    pub fn new(x: u8) -> Self {
        SelfReferential {
            foo_ptr: ::std::ptr::null(),
            x,
        }
    }
    pub fn reference_self(self: PinMut<Self>) {
        let foo_ptr = &self.x as *const _;
        unsafe { PinMut::get_mut(self) }.foo_ptr = foo_ptr;
    }
    pub fn deref_ptr(&self) {
        if self.foo_ptr != ::std::ptr::null() {
            println!("{:?}", unsafe { *self.foo_ptr });
        }
    }
}

fn main() {
    let x = SelfReferential::new(x);
    x.deref_ptr();
    pin!(x);
    x.reference_self();
    x.deref_ptr();
}