rust/src/test/run-pass/issue-28936.rs

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

pub type Session = i32;
pub struct StreamParser<'a, T> {
    _tokens: T,
    _session: &'a mut Session,
}

impl<'a, T> StreamParser<'a, T> {
    pub fn thing(&mut self) -> bool { true }
}

pub fn parse_stream<T: Iterator<Item=i32>, U, F>(
        _session: &mut Session, _tokens: T, _f: F) -> U
    where F: Fn(&mut StreamParser<T>) -> U { panic!(); }

pub fn thing(session: &mut Session) {
    let mut stream = vec![1, 2, 3].into_iter();

    let _b = parse_stream(session,
                          stream.by_ref(),
                          // replacing the above with the following fixes it
                          //&mut stream,
                          |p| p.thing());

}

fn main() {}