std: Second pass stabilization for `comm`

This commit is a second pass stabilization for the `std::comm` module,
performing the following actions:

* The entire `std::comm` module was moved under `std::sync::mpsc`. This movement
  reflects that channels are just yet another synchronization primitive, and
  they don't necessarily deserve a special place outside of the other
  concurrency primitives that the standard library offers.
* The `send` and `recv` methods have all been removed.
* The `send_opt` and `recv_opt` methods have been renamed to `send` and `recv`.
  This means that all send/receive operations return a `Result` now indicating
  whether the operation was successful or not.
* The error type of `send` is now a `SendError` to implement a custom error
  message and allow for `unwrap()`. The error type contains an `into_inner`
  method to extract the value.
* The error type of `recv` is now `RecvError` for the same reasons as `send`.
* The `TryRecvError` and `TrySendError` types have had public reexports removed
  of their variants and the variant names have been tweaked with enum
  namespacing rules.
* The `Messages` iterator is renamed to `Iter`

This functionality is now all `#[stable]`:

* `Sender`
* `SyncSender`
* `Receiver`
* `std::sync::mpsc`
* `channel`
* `sync_channel`
* `Iter`
* `Sender::send`
* `Sender::clone`
* `SyncSender::send`
* `SyncSender::try_send`
* `SyncSender::clone`
* `Receiver::recv`
* `Receiver::try_recv`
* `Receiver::iter`
* `SendError`
* `RecvError`
* `TrySendError::{mod, Full, Disconnected}`
* `TryRecvError::{mod, Empty, Disconnected}`
* `SendError::into_inner`
* `TrySendError::into_inner`

This is a breaking change due to the modification of where this module is
located, as well as the changing of the semantics of `send` and `recv`. Most
programs just need to rename imports of `std::comm` to `std::sync::mpsc` and
add calls to `unwrap` after a send or a receive operation.

[breaking-change]

1 files changed, 9 insertions, 9 deletions

diff --git a/src/libstd/sync/future.rs b/src/libstd/sync/future.rs
index a0e7236b8d2..e3620617d57 100644
--- a/src/libstd/sync/future.rs
+++ b/src/libstd/sync/future.rs
@@ -28,7 +28,7 @@ use core::prelude::*;
 use core::mem::replace;
 
 use self::FutureState::*;
-use comm::{Receiver, channel};
+use sync::mpsc::{Receiver, channel};
 use thunk::{Thunk};
 use thread::Thread;
 
@@ -122,8 +122,8 @@ impl<A:Send> Future<A> {
          * waiting for the result to be received on the port.
          */
 
-        Future::from_fn(move|:| {
-            rx.recv()
+        Future::from_fn(move |:| {
+            rx.recv().unwrap()
         })
     }
 
@@ -141,7 +141,7 @@ impl<A:Send> Future<A> {
 
         Thread::spawn(move |:| {
             // Don't panic if the other end has hung up
-            let _ = tx.send_opt(blk());
+            let _ = tx.send(blk());
         }).detach();
 
         Future::from_receiver(rx)
@@ -151,7 +151,7 @@ impl<A:Send> Future<A> {
 #[cfg(test)]
 mod test {
     use prelude::v1::*;
-    use comm::channel;
+    use sync::mpsc::channel;
     use sync::Future;
     use thread::Thread;
 
@@ -164,7 +164,7 @@ mod test {
     #[test]
     fn test_from_receiver() {
         let (tx, rx) = channel();
-        tx.send("whale".to_string());
+        tx.send("whale".to_string()).unwrap();
         let mut f = Future::from_receiver(rx);
         assert_eq!(f.get(), "whale");
     }
@@ -184,7 +184,7 @@ mod test {
     #[test]
     fn test_interface_unwrap() {
         let f = Future::from_value("fail".to_string());
-        assert_eq!(f.unwrap(), "fail");
+        assert_eq!(f.into_inner(), "fail");
     }
 
     #[test]
@@ -213,8 +213,8 @@ mod test {
         let f = Future::spawn(move|| { expected });
         let _t = Thread::spawn(move|| {
             let mut f = f;
-            tx.send(f.get());
+            tx.send(f.get()).unwrap();
         });
-        assert_eq!(rx.recv(), expected);
+        assert_eq!(rx.recv().unwrap(), expected);
     }
 }