Require <T: Send> for AtomicOption

Fixes #19247.

src/libsync/atomic.rs

@@ -96,7 +96,7 @@
 
 use alloc::boxed::Box;
 use core::mem;
-use core::prelude::{Drop, None, Option, Some};
+use core::prelude::{Send, Drop, None, Option, Some};
 
 pub use core::atomic::{AtomicBool, AtomicInt, AtomicUint, AtomicPtr};
 pub use core::atomic::{Ordering, Relaxed, Release, Acquire, AcqRel, SeqCst};
@@ -114,7 +114,7 @@ pub struct AtomicOption<T> {
     p: AtomicUint,
 }
 
-impl<T> AtomicOption<T> {
+impl<T: Send> AtomicOption<T> {
     /// Create a new `AtomicOption`
     pub fn new(p: Box<T>) -> AtomicOption<T> {
         unsafe { AtomicOption { p: AtomicUint::new(mem::transmute(p)) } }
@@ -170,7 +170,7 @@ impl<T> AtomicOption<T> {
 }
 
 #[unsafe_destructor]
-impl<T> Drop for AtomicOption<T> {
+impl<T: Send> Drop for AtomicOption<T> {
     fn drop(&mut self) {
         let _ = self.take(SeqCst);
     }

src/test/compile-fail/atomicoption-not-send-ref.rs

@@ -0,0 +1,16 @@
+// Copyright 2014 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.
+
+use std::sync::atomic::AtomicOption;
+
+fn main() {
+    let x = 0u;
+    AtomicOption::new(box &x);  //~ ERROR `x` does not live long enough
+}

src/test/compile-fail/atomicoption-not-send.rs

@@ -0,0 +1,16 @@
+// Copyright 2014 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.
+
+use std::kinds::marker;
+use std::sync::atomic::AtomicOption;
+
+fn main() {
+    AtomicOption::new(box marker::NoSend);  //~ ERROR `core::kinds::Send` is not implemented
+}