Explicitly opt out of `Sync` for `cell` and `mpsc` types

These types were already `!Sync`, but this improves error messages when
they are used in contexts that require `Sync`, aligning them with
conventions used with `Rc`, among others.

6 files changed, 46 insertions, 54 deletions

diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index 255c846244b..144adde12e4 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -242,6 +242,9 @@ impl<T:Copy> Cell<T> {
 unsafe impl<T> Send for Cell<T> where T: Send {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
+impl<T> !Sync for Cell<T> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T:Copy> Clone for Cell<T> {
     #[inline]
     fn clone(&self) -> Cell<T> {
@@ -462,6 +465,9 @@ impl<T: ?Sized> RefCell<T> {
 unsafe impl<T: ?Sized> Send for RefCell<T> where T: Send {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized> !Sync for RefCell<T> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Clone> Clone for RefCell<T> {
     #[inline]
     fn clone(&self) -> RefCell<T> {
diff --git a/src/libstd/sync/mpsc/mod.rs b/src/libstd/sync/mpsc/mod.rs
index fadca390986..dbcc2bc95bc 100644
--- a/src/libstd/sync/mpsc/mod.rs
+++ b/src/libstd/sync/mpsc/mod.rs
@@ -299,6 +299,9 @@ pub struct Receiver<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 unsafe impl<T: Send> Send for Receiver<T> { }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> !Sync for Receiver<T> { }
+
 /// An iterator over messages on a receiver, this iterator will block
 /// whenever `next` is called, waiting for a new message, and `None` will be
 /// returned when the corresponding channel has hung up.
@@ -327,6 +330,9 @@ pub struct Sender<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 unsafe impl<T: Send> Send for Sender<T> { }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> !Sync for Sender<T> { }
+
 /// The sending-half of Rust's synchronous channel type. This half can only be
 /// owned by one thread, but it can be cloned to send to other threads.
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/test/compile-fail/comm-not-freeze-receiver.rs b/src/test/compile-fail/comm-not-freeze-receiver.rs
deleted file mode 100644
index 305acfec401..00000000000
--- a/src/test/compile-fail/comm-not-freeze-receiver.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 <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::mpsc::Receiver;
-
-fn test<T: Sync>() {}
-
-fn main() {
-    test::<Receiver<isize>>();   //~ ERROR: `core::marker::Sync` is not implemented
-}
diff --git a/src/test/compile-fail/comm-not-freeze.rs b/src/test/compile-fail/comm-not-freeze.rs
deleted file mode 100644
index de2c96920c3..00000000000
--- a/src/test/compile-fail/comm-not-freeze.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 <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::mpsc::Sender;
-
-fn test<T: Sync>() {}
-
-fn main() {
-    test::<Sender<isize>>();     //~ ERROR: `core::marker::Sync` is not implemented
-}
diff --git a/src/test/compile-fail/no_share-rc.rs b/src/test/compile-fail/no_share-rc.rs
deleted file mode 100644
index 4bc3442871f..00000000000
--- a/src/test/compile-fail/no_share-rc.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-// 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 <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::rc::Rc;
-use std::cell::RefCell;
-
-fn bar<T: Sync>(_: T) {}
-
-fn main() {
-    let x = Rc::new(RefCell::new(5));
-    bar(x);
-    //~^ ERROR the trait `core::marker::Sync` is not implemented
-}
diff --git a/src/test/compile-fail/not-sync.rs b/src/test/compile-fail/not-sync.rs
new file mode 100644
index 00000000000..a60138c6e1f
--- /dev/null
+++ b/src/test/compile-fail/not-sync.rs
@@ -0,0 +1,34 @@
+// 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.
+
+use std::cell::{Cell, RefCell};
+use std::rc::{Rc, Weak};
+use std::sync::mpsc::{Receiver, Sender, SyncSender};
+
+fn test<T: Sync>() {}
+
+fn main() {
+    test::<Cell<i32>>();
+    //~^ ERROR marker::Sync` is not implemented for the type `core::cell::Cell<i32>`
+    test::<RefCell<i32>>();
+    //~^ ERROR marker::Sync` is not implemented for the type `core::cell::RefCell<i32>`
+
+    test::<Rc<i32>>();
+    //~^ ERROR marker::Sync` is not implemented for the type `alloc::rc::Rc<i32>`
+    test::<Weak<i32>>();
+    //~^ ERROR marker::Sync` is not implemented for the type `alloc::rc::Weak<i32>`
+
+    test::<Receiver<i32>>();
+    //~^ ERROR marker::Sync` is not implemented for the type `std::sync::mpsc::Receiver<i32>`
+    test::<Sender<i32>>();
+    //~^ ERROR marker::Sync` is not implemented for the type `std::sync::mpsc::Sender<i32>`
+    test::<SyncSender<i32>>();
+    //~^ ERROR marker::Sync` is not implemented for the type `std::sync::mpsc::SyncSender<i32>`
+}