rust/tests/run-pass/ice-2774.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.

use std::collections::HashSet;

// See https://github.com/rust-lang/rust-clippy/issues/2774

#[derive(Eq, PartialEq, Debug, Hash)]
pub struct Bar {
    foo: Foo,
}

#[derive(Eq, PartialEq, Debug, Hash)]
pub struct Foo {}

#[allow(clippy::implicit_hasher)]
// This should not cause a 'cannot relate bound region' ICE
pub fn add_barfoos_to_foos<'a>(bars: &HashSet<&'a Bar>) {
    let mut foos = HashSet::new();
    foos.extend(bars.iter().map(|b| &b.foo));
}

#[allow(clippy::implicit_hasher)]
// Also this should not cause a 'cannot relate bound region' ICE
pub fn add_barfoos_to_foos2(bars: &HashSet<&Bar>) {
    let mut foos = HashSet::new();
    foos.extend(bars.iter().map(|b| &b.foo));
}

fn main() {}