// Copyright 2012 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. extern crate collections; use std::collections::HashSet; struct Foo { n: HashSet, } impl Foo { pub fn foo(&mut self, mut fun: F) where F: FnMut(&isize) { for f in self.n.iter() { fun(f); } } } fn bar(f: &mut Foo) { f.foo( |a| { //~ ERROR closure requires unique access to `f` f.n.insert(*a); }) } fn main() { let mut f = Foo { n: HashSet::new() }; bar(&mut f); }