Implement RFC 458: improve Send

src/libcore/marker.rs

@@ -32,9 +32,19 @@ use clone::Clone;
            reason = "will be overhauled with new lifetime rules; see RFC 458")]
 #[lang="send"]
 #[rustc_on_unimplemented = "`{Self}` cannot be sent between threads safely"]
+#[cfg(stage0)] // SNAP ac134f7 remove after stage0
 pub unsafe trait Send: 'static {
     // empty.
 }
+/// Types able to be transferred across thread boundaries.
+#[unstable(feature = "core",
+           reason = "will be overhauled with new lifetime rules; see RFC 458")]
+#[lang="send"]
+#[rustc_on_unimplemented = "`{Self}` cannot be sent between threads safely"]
+#[cfg(not(stage0))]
+pub unsafe trait Send {
+    // empty.
+}
 
 /// Types with a constant size known at compile-time.
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -424,3 +434,11 @@ pub struct NoCopy;
 #[lang="managed_bound"]
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Managed;
+
+#[cfg(not(stage0))] // SNAP ac134f7 remove this attribute after the next snapshot
+mod impls {
+    use super::{Send, Sync, Sized};
+
+    unsafe impl<'a, T: Sync + ?Sized> Send for &'a T {}
+    unsafe impl<'a, T: Send + ?Sized> Send for &'a mut T {}
+}

src/librustc/middle/traits/select.rs

@@ -20,7 +20,7 @@ use self::EvaluationResult::*;
 use super::{DerivedObligationCause};
 use super::{project};
 use super::project::Normalized;
-use super::{PredicateObligation, Obligation, TraitObligation, ObligationCause};
+use super::{PredicateObligation, TraitObligation, ObligationCause};
 use super::{ObligationCauseCode, BuiltinDerivedObligation};
 use super::{SelectionError, Unimplemented, Overflow, OutputTypeParameterMismatch};
 use super::{Selection};
@@ -34,7 +34,7 @@ use super::{util};
 use middle::fast_reject;
 use middle::mem_categorization::Typer;
 use middle::subst::{Subst, Substs, TypeSpace, VecPerParamSpace};
-use middle::ty::{self, AsPredicate, RegionEscape, ToPolyTraitRef, Ty};
+use middle::ty::{self, RegionEscape, ToPolyTraitRef, Ty};
 use middle::infer;
 use middle::infer::{InferCtxt, TypeFreshener};
 use middle::ty_fold::TypeFoldable;
@@ -1459,22 +1459,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
                     ty::BoundSync |
                     ty::BoundSend => {
-                        // Note: technically, a region pointer is only
-                        // sendable if it has lifetime
-                        // `'static`. However, we don't take regions
-                        // into account when doing trait matching:
-                        // instead, when we decide that `T : Send`, we
-                        // will register a separate constraint with
-                        // the region inferencer that `T : 'static`
-                        // holds as well (because the trait `Send`
-                        // requires it). This will ensure that there
-                        // is no borrowed data in `T` (or else report
-                        // an inference error). The reason we do it
-                        // this way is that we do not yet *know* what
-                        // lifetime the borrowed reference has, since
-                        // we haven't finished running inference -- in
-                        // other words, there's a kind of
-                        // chicken-and-egg problem.
                         Ok(If(vec![referent_ty]))
                     }
                 }
@@ -1817,21 +1801,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 }
             })
         }).collect::<Result<_, _>>();
-        let mut obligations = match obligations {
+        let obligations = match obligations {
             Ok(o) => o,
             Err(ErrorReported) => Vec::new()
         };
 
-        // as a special case, `Send` requires `'static`
-        if bound == ty::BoundSend {
-            obligations.push(Obligation {
-                cause: obligation.cause.clone(),
-                recursion_depth: obligation.recursion_depth+1,
-                predicate: ty::Binder(ty::OutlivesPredicate(obligation.self_ty(),
-                                                            ty::ReStatic)).as_predicate(),
-            });
-        }
-
         let obligations = VecPerParamSpace::new(obligations, Vec::new(), Vec::new());
 
         debug!("vtable_builtin_data: obligations={}",

src/librustc/util/ppaux.rs

@@ -697,9 +697,8 @@ impl<'tcx> UserString<'tcx> for ty::TyTrait<'tcx> {
         }
 
         // Region, if not obviously implied by builtin bounds.
-        if bounds.region_bound != ty::ReStatic ||
-            !bounds.builtin_bounds.contains(&ty::BoundSend)
-        { // Region bound is implied by builtin bounds:
+        if bounds.region_bound != ty::ReStatic {
+            // Region bound is implied by builtin bounds:
             components.push(bounds.region_bound.user_string(tcx));
         }
 

src/libstd/old_io/net/pipe.rs

@@ -287,7 +287,7 @@ mod tests {
 
     pub fn smalltest<F,G>(server: F, client: G)
         where F : FnOnce(UnixStream), F : Send,
-              G : FnOnce(UnixStream), G : Send
+              G : FnOnce(UnixStream), G : Send + 'static
     {
         let path1 = next_test_unix();
         let path2 = path1.clone();

src/libstd/process.rs

@@ -458,7 +458,7 @@ impl Child {
     /// the parent waits for the child to exit.
     pub fn wait_with_output(mut self) -> io::Result<Output> {
         drop(self.stdin.take());
-        fn read<T: Read + Send>(stream: Option<T>) -> Receiver<io::Result<Vec<u8>>> {
+        fn read<T: Read + Send + 'static>(stream: Option<T>) -> Receiver<io::Result<Vec<u8>>> {
             let (tx, rx) = channel();
             match stream {
                 Some(stream) => {

src/libstd/rt/at_exit_imp.rs

@@ -20,7 +20,7 @@ use mem;
 use thunk::Thunk;
 use sys_common::mutex::{Mutex, MUTEX_INIT};
 
-type Queue = Vec<Thunk>;
+type Queue = Vec<Thunk<'static>>;
 
 // NB these are specifically not types from `std::sync` as they currently rely
 // on poisoning and this module needs to operate at a lower level than requiring
@@ -65,7 +65,7 @@ pub fn cleanup() {
     }
 }
 
-pub fn push(f: Thunk) {
+pub fn push(f: Thunk<'static>) {
     unsafe {
         LOCK.lock();
         init();

src/libstd/rt/mod.rs

@@ -148,7 +148,7 @@ fn lang_start(main: *const u8, argc: int, argv: *const *const u8) -> int {
 ///
 /// It is forbidden for procedures to register more `at_exit` handlers when they
 /// are running, and doing so will lead to a process abort.
-pub fn at_exit<F:FnOnce()+Send>(f: F) {
+pub fn at_exit<F:FnOnce()+Send+'static>(f: F) {
     at_exit_imp::push(Thunk::new(f));
 }
 

src/libstd/rt/unwind.rs

@@ -74,7 +74,7 @@ use rt::libunwind as uw;
 
 struct Exception {
     uwe: uw::_Unwind_Exception,
-    cause: Option<Box<Any + Send>>,
+    cause: Option<Box<Any + Send + 'static>>,
 }
 
 pub type Callback = fn(msg: &(Any + Send), file: &'static str, line: uint);
@@ -161,7 +161,7 @@ pub fn panicking() -> bool {
 #[inline(never)]
 #[no_mangle]
 #[allow(private_no_mangle_fns)]
-fn rust_panic(cause: Box<Any + Send>) -> ! {
+fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
     rtdebug!("begin_unwind()");
 
     unsafe {

src/libstd/sync/future.rs

@@ -46,7 +46,7 @@ pub struct Future<A> {
 }
 
 enum FutureState<A> {
-    Pending(Thunk<(),A>),
+    Pending(Thunk<'static,(),A>),
     Evaluating,
     Forced(A)
 }
@@ -103,7 +103,7 @@ impl<A> Future<A> {
     }
 
     pub fn from_fn<F>(f: F) -> Future<A>
-        where F : FnOnce() -> A, F : Send
+        where F : FnOnce() -> A, F : Send + 'static
     {
         /*!
          * Create a future from a function.
@@ -117,7 +117,7 @@ impl<A> Future<A> {
     }
 }
 
-impl<A:Send> Future<A> {
+impl<A:Send+'static> Future<A> {
     pub fn from_receiver(rx: Receiver<A>) -> Future<A> {
         /*!
          * Create a future from a port
@@ -132,7 +132,7 @@ impl<A:Send> Future<A> {
     }
 
     pub fn spawn<F>(blk: F) -> Future<A>
-        where F : FnOnce() -> A, F : Send
+        where F : FnOnce() -> A, F : Send + 'static
     {
         /*!
          * Create a future from a unique closure.

src/libstd/sync/mpsc/mod.rs

@@ -345,7 +345,7 @@ pub struct Receiver<T> {
 
 // The receiver port can be sent from place to place, so long as it
 // is not used to receive non-sendable things.
-unsafe impl<T:Send> Send for Receiver<T> { }
+unsafe impl<T: Send + 'static> Send 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
@@ -364,7 +364,7 @@ pub struct Sender<T> {
 
 // The send port can be sent from place to place, so long as it
 // is not used to send non-sendable things.
-unsafe impl<T:Send> Send for Sender<T> { }
+unsafe impl<T: Send + 'static> Send for Sender<T> { }
 
 /// The sending-half of Rust's synchronous channel type. This half can only be
 /// owned by one task, but it can be cloned to send to other tasks.
@@ -373,7 +373,7 @@ pub struct SyncSender<T> {
     inner: Arc<UnsafeCell<sync::Packet<T>>>,
 }
 
-unsafe impl<T:Send> Send for SyncSender<T> {}
+unsafe impl<T: Send + 'static> Send for SyncSender<T> {}
 
 impl<T> !Sync for SyncSender<T> {}
 
@@ -485,7 +485,7 @@ impl<T> UnsafeFlavor<T> for Receiver<T> {
 /// println!("{:?}", rx.recv().unwrap());
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-pub fn channel<T: Send>() -> (Sender<T>, Receiver<T>) {
+pub fn channel<T: Send + 'static>() -> (Sender<T>, Receiver<T>) {
     let a = Arc::new(UnsafeCell::new(oneshot::Packet::new()));
     (Sender::new(Flavor::Oneshot(a.clone())), Receiver::new(Flavor::Oneshot(a)))
 }
@@ -525,7 +525,7 @@ pub fn channel<T: Send>() -> (Sender<T>, Receiver<T>) {
 /// assert_eq!(rx.recv().unwrap(), 2);
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-pub fn sync_channel<T: Send>(bound: uint) -> (SyncSender<T>, Receiver<T>) {
+pub fn sync_channel<T: Send + 'static>(bound: uint) -> (SyncSender<T>, Receiver<T>) {
     let a = Arc::new(UnsafeCell::new(sync::Packet::new(bound)));
     (SyncSender::new(a.clone()), Receiver::new(Flavor::Sync(a)))
 }
@@ -534,7 +534,7 @@ pub fn sync_channel<T: Send>(bound: uint) -> (SyncSender<T>, Receiver<T>) {
 // Sender
 ////////////////////////////////////////////////////////////////////////////////
 
-impl<T: Send> Sender<T> {
+impl<T: Send + 'static> Sender<T> {
     fn new(inner: Flavor<T>) -> Sender<T> {
         Sender {
             inner: UnsafeCell::new(inner),
@@ -616,7 +616,7 @@ impl<T: Send> Sender<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Clone for Sender<T> {
+impl<T: Send + 'static> Clone for Sender<T> {
     fn clone(&self) -> Sender<T> {
         let (packet, sleeper, guard) = match *unsafe { self.inner() } {
             Flavor::Oneshot(ref p) => {
@@ -662,7 +662,7 @@ impl<T: Send> Clone for Sender<T> {
 
 #[unsafe_destructor]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Drop for Sender<T> {
+impl<T: Send + 'static> Drop for Sender<T> {
     fn drop(&mut self) {
         match *unsafe { self.inner_mut() } {
             Flavor::Oneshot(ref mut p) => unsafe { (*p.get()).drop_chan(); },
@@ -677,7 +677,7 @@ impl<T: Send> Drop for Sender<T> {
 // SyncSender
 ////////////////////////////////////////////////////////////////////////////////
 
-impl<T: Send> SyncSender<T> {
+impl<T: Send + 'static> SyncSender<T> {
     fn new(inner: Arc<UnsafeCell<sync::Packet<T>>>) -> SyncSender<T> {
         SyncSender { inner: inner }
     }
@@ -717,7 +717,7 @@ impl<T: Send> SyncSender<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Clone for SyncSender<T> {
+impl<T: Send + 'static> Clone for SyncSender<T> {
     fn clone(&self) -> SyncSender<T> {
         unsafe { (*self.inner.get()).clone_chan(); }
         return SyncSender::new(self.inner.clone());
@@ -726,7 +726,7 @@ impl<T: Send> Clone for SyncSender<T> {
 
 #[unsafe_destructor]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Drop for SyncSender<T> {
+impl<T: Send + 'static> Drop for SyncSender<T> {
     fn drop(&mut self) {
         unsafe { (*self.inner.get()).drop_chan(); }
     }
@@ -736,7 +736,7 @@ impl<T: Send> Drop for SyncSender<T> {
 // Receiver
 ////////////////////////////////////////////////////////////////////////////////
 
-impl<T: Send> Receiver<T> {
+impl<T: Send + 'static> Receiver<T> {
     fn new(inner: Flavor<T>) -> Receiver<T> {
         Receiver { inner: UnsafeCell::new(inner) }
     }
@@ -855,7 +855,7 @@ impl<T: Send> Receiver<T> {
     }
 }
 
-impl<T: Send> select::Packet for Receiver<T> {
+impl<T: Send + 'static> select::Packet for Receiver<T> {
     fn can_recv(&self) -> bool {
         loop {
             let new_port = match *unsafe { self.inner() } {
@@ -942,15 +942,15 @@ impl<T: Send> select::Packet for Receiver<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: Send> Iterator for Iter<'a, T> {
+impl<'a, T: Send + 'static> Iterator for Iter<'a, T> {
     type Item = T;
 
     fn next(&mut self) -> Option<T> { self.rx.recv().ok() }
 }
 
 #[unsafe_destructor]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Drop for Receiver<T> {
+impl<T: Send + 'static> Drop for Receiver<T> {
     fn drop(&mut self) {
         match *unsafe { self.inner_mut() } {
             Flavor::Oneshot(ref mut p) => unsafe { (*p.get()).drop_port(); },

src/libstd/sync/mpsc/mpsc_queue.rs

@@ -78,7 +78,7 @@ pub struct Queue<T> {
 }
 
 unsafe impl<T:Send> Send for Queue<T> { }
-unsafe impl<T:Send> Sync for Queue<T> { }
+unsafe impl<T: Send + 'static> Sync for Queue<T> { }
 
 impl<T> Node<T> {
     unsafe fn new(v: Option<T>) -> *mut Node<T> {
@@ -89,7 +89,7 @@ impl<T> Node<T> {
     }
 }
 
-impl<T: Send> Queue<T> {
+impl<T: Send + 'static> Queue<T> {
     /// Creates a new queue that is safe to share among multiple producers and
     /// one consumer.
     pub fn new() -> Queue<T> {
@@ -140,7 +140,7 @@ impl<T: Send> Queue<T> {
 
 #[unsafe_destructor]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Drop for Queue<T> {
+impl<T: Send + 'static> Drop for Queue<T> {
     fn drop(&mut self) {
         unsafe {
             let mut cur = *self.tail.get();

src/libstd/sync/mpsc/oneshot.rs

@@ -88,7 +88,7 @@ enum MyUpgrade<T> {
     GoUp(Receiver<T>),
 }
 
-impl<T: Send> Packet<T> {
+impl<T: Send + 'static> Packet<T> {
     pub fn new() -> Packet<T> {
         Packet {
             data: None,
@@ -368,7 +368,7 @@ impl<T: Send> Packet<T> {
 }
 
 #[unsafe_destructor]
-impl<T: Send> Drop for Packet<T> {
+impl<T: Send + 'static> Drop for Packet<T> {
     fn drop(&mut self) {
         assert_eq!(self.state.load(Ordering::SeqCst), DISCONNECTED);
     }