+// Copyright 2016 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.
+
+// pretty-expanded FIXME #23616
+
+fn main() {
+ let _ = test(Some(0).into_iter());
+}
+
+trait Parser {
+ type Input: Iterator;
+ type Output;
+ fn parse(self, input: Self::Input) -> Result<(Self::Output, Self::Input), ()>;
+ fn chain<P>(self, p: P) -> Chain<Self, P> where Self: Sized {
+ Chain(self, p)
+ }
+}
+
+struct Token<T>(T::Item) where T: Iterator;
+
+impl<T> Parser for Token<T> where T: Iterator {
+ type Input = T;
+ type Output = T::Item;
+ fn parse(self, _input: Self::Input) -> Result<(Self::Output, Self::Input), ()> {
+ Err(())
+ }
+}
+
+struct Chain<L, R>(L, R);
+
+impl<L, R> Parser for Chain<L, R> where L: Parser, R: Parser<Input = L::Input> {
+ type Input = L::Input;
+ type Output = (L::Output, R::Output);
+ fn parse(self, _input: Self::Input) -> Result<(Self::Output, Self::Input), ()> {
+ Err(())
+ }
+}
+
+fn test<I>(i: I) -> Result<((), I), ()> where I: Iterator<Item = i32> {
+ Chain(Token(0), Token(1))
+ .chain(Chain(Token(0), Token(1)))
+ .chain(Chain(Token(0), Token(1)))
+ .chain(Chain(Token(0), Token(1)))
+ .chain(Chain(Token(0), Token(1)))
+ .chain(Chain(Token(0), Token(1)))
+ .chain(Chain(Token(0), Token(1)))
+ .chain(Chain(Token(0), Token(1)))
+ .chain(Chain(Token(0), Token(1)))
+ .parse(i)
+ .map(|(_, i)| ((), i))
+}