// Copyright 2013 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::rc::Rc; use std::cell::RefCell; trait Foo { fn set(&mut self, v: Rc>); } struct B { v: Option>> } impl Foo for B { fn set(&mut self, v: Rc>) { self.v = Some(v); } } struct A { v: ~Foo, } fn main() { let a = A {v: ~B{v: None} as ~Foo}; //~^ ERROR cannot pack type `~B`, which does not fulfill `Send` let v = Rc::new(RefCell::new(a)); let w = v.clone(); let b = v.borrow(); let mut b = b.borrow_mut(); b.get().v.set(w.clone()); }