// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![deny(clippy::all)] #[allow(dead_code)] struct Foo; impl Iterator for Foo { type Item = (); fn next(&mut self) -> Option<()> { let _ = self.len() == 0; unimplemented!() } } impl ExactSizeIterator for Foo {} fn main() {}