// 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. use std::collections::HashMap; use std::collections::hash_map::Entry::Vacant; pub fn foo() { type F = Box; let mut map: HashMap<(), F> = HashMap::new(); let x: &mut F = match map.entry(()) { Vacant(_) => unimplemented!(), _ => unimplemented!() }; } fn main() {}