Auto merge of #29206 - apasel422:issue-28936, r=alexcrichton

Closes #28936.

Author: bors

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

@@ -0,0 +1,36 @@
+// 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() {}