rust/tests/run-pass/ice_exacte_size.rs

// 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 <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.

#![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() {}