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// Copyright 2016 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 <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.
// ignore-tidy-linelength
#![feature(conservative_impl_trait)]
use std::cell::Cell;
use std::rc::Rc;
// Fast path, main can see the concrete type returned.
fn before() -> impl Fn(i32) {
let p = Rc::new(Cell::new(0));
move |x| p.set(x)
}
fn send<T: Send>(_: T) {}
fn main() {
send(before());
//~^ ERROR the trait bound `std::rc::Rc<std::cell::Cell<i32>>: std::marker::Send` is not satisfied
//~| NOTE the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::cell::Cell<i32>>`
//~| NOTE `std::rc::Rc<std::cell::Cell<i32>>` cannot be sent between threads safely
//~| NOTE required because it appears within the type `[closure
//~| NOTE required because it appears within the type `impl std::ops::Fn<(i32,)>`
//~| NOTE required by `send`
send(after());
//~^ ERROR the trait bound `std::rc::Rc<std::cell::Cell<i32>>: std::marker::Send` is not satisfied
//~| NOTE the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::cell::Cell<i32>>`
//~| NOTE `std::rc::Rc<std::cell::Cell<i32>>` cannot be sent between threads safely
//~| NOTE required because it appears within the type `[closure
//~| NOTE required because it appears within the type `impl std::ops::Fn<(i32,)>`
//~| NOTE required by `send`
}
// Deferred path, main has to wait until typeck finishes,
// to check if the return type of after is Send.
fn after() -> impl Fn(i32) {
let p = Rc::new(Cell::new(0));
move |x| p.set(x)
}
// Cycles should work as the deferred obligations are
// independently resolved and only require the concrete
// return type, which can't depend on the obligation.
fn cycle1() -> impl Clone {
send(cycle2().clone());
//~^ ERROR the trait bound `std::rc::Rc<std::string::String>: std::marker::Send` is not satisfied
//~| NOTE the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::string::String>`
//~| NOTE `std::rc::Rc<std::string::String>` cannot be sent between threads safely
//~| NOTE required because it appears within the type `impl std::clone::Clone`
//~| NOTE required by `send`
Rc::new(Cell::new(5))
}
fn cycle2() -> impl Clone {
send(cycle1().clone());
//~^ ERROR the trait bound `std::rc::Rc<std::cell::Cell<i32>>: std::marker::Send` is not satisfied
//~| NOTE the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::cell::Cell<i32>>`
//~| NOTE `std::rc::Rc<std::cell::Cell<i32>>` cannot be sent between threads safely
//~| NOTE required because it appears within the type `impl std::clone::Clone`
//~| NOTE required by `send`
Rc::new(String::from("foo"))
}
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