Auto merge of #23963 - alexcrichton:rollup, r=alexcrichton

9 files changed, 58 insertions, 56 deletions

diff --git a/src/libstd/sync/mpsc/mod.rs b/src/libstd/sync/mpsc/mod.rs
index e14f32865fa..c80182ec07d 100644
--- a/src/libstd/sync/mpsc/mod.rs
+++ b/src/libstd/sync/mpsc/mod.rs
@@ -342,7 +342,7 @@ mod spsc_queue;
 /// The receiving-half of Rust's channel type. This half can only be owned by
 /// one task
 #[stable(feature = "rust1", since = "1.0.0")]
-pub struct Receiver<T:Send> {
+pub struct Receiver<T> {
     inner: UnsafeCell<Flavor<T>>,
 }
 
@@ -354,14 +354,14 @@ unsafe impl<T: Send> Send for Receiver<T> { }
 /// whenever `next` is called, waiting for a new message, and `None` will be
 /// returned when the corresponding channel has hung up.
 #[stable(feature = "rust1", since = "1.0.0")]
-pub struct Iter<'a, T:Send+'a> {
+pub struct Iter<'a, T: 'a> {
     rx: &'a Receiver<T>
 }
 
 /// The sending-half of Rust's asynchronous channel type. This half can only be
 /// owned by one task, but it can be cloned to send to other tasks.
 #[stable(feature = "rust1", since = "1.0.0")]
-pub struct Sender<T:Send> {
+pub struct Sender<T> {
     inner: UnsafeCell<Flavor<T>>,
 }
 
@@ -372,7 +372,7 @@ unsafe impl<T: Send> 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.
 #[stable(feature = "rust1", since = "1.0.0")]
-pub struct SyncSender<T: Send> {
+pub struct SyncSender<T> {
     inner: Arc<UnsafeCell<sync::Packet<T>>>,
 }
 
@@ -433,7 +433,7 @@ pub enum TrySendError<T> {
     Disconnected(T),
 }
 
-enum Flavor<T:Send> {
+enum Flavor<T> {
     Oneshot(Arc<UnsafeCell<oneshot::Packet<T>>>),
     Stream(Arc<UnsafeCell<stream::Packet<T>>>),
     Shared(Arc<UnsafeCell<shared::Packet<T>>>),
@@ -441,7 +441,7 @@ enum Flavor<T:Send> {
 }
 
 #[doc(hidden)]
-trait UnsafeFlavor<T:Send> {
+trait UnsafeFlavor<T> {
     fn inner_unsafe<'a>(&'a self) -> &'a UnsafeCell<Flavor<T>>;
     unsafe fn inner_mut<'a>(&'a self) -> &'a mut Flavor<T> {
         &mut *self.inner_unsafe().get()
@@ -450,12 +450,12 @@ trait UnsafeFlavor<T:Send> {
         &*self.inner_unsafe().get()
     }
 }
-impl<T:Send> UnsafeFlavor<T> for Sender<T> {
+impl<T> UnsafeFlavor<T> for Sender<T> {
     fn inner_unsafe<'a>(&'a self) -> &'a UnsafeCell<Flavor<T>> {
         &self.inner
     }
 }
-impl<T:Send> UnsafeFlavor<T> for Receiver<T> {
+impl<T> UnsafeFlavor<T> for Receiver<T> {
     fn inner_unsafe<'a>(&'a self) -> &'a UnsafeCell<Flavor<T>> {
         &self.inner
     }
@@ -488,7 +488,7 @@ impl<T:Send> 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>() -> (Sender<T>, Receiver<T>) {
     let a = Arc::new(UnsafeCell::new(oneshot::Packet::new()));
     (Sender::new(Flavor::Oneshot(a.clone())), Receiver::new(Flavor::Oneshot(a)))
 }
@@ -528,7 +528,7 @@ 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: usize) -> (SyncSender<T>, Receiver<T>) {
+pub fn sync_channel<T>(bound: usize) -> (SyncSender<T>, Receiver<T>) {
     let a = Arc::new(UnsafeCell::new(sync::Packet::new(bound)));
     (SyncSender::new(a.clone()), Receiver::new(Flavor::Sync(a)))
 }
@@ -537,7 +537,7 @@ pub fn sync_channel<T: Send>(bound: usize) -> (SyncSender<T>, Receiver<T>) {
 // Sender
 ////////////////////////////////////////////////////////////////////////////////
 
-impl<T: Send> Sender<T> {
+impl<T> Sender<T> {
     fn new(inner: Flavor<T>) -> Sender<T> {
         Sender {
             inner: UnsafeCell::new(inner),
@@ -619,7 +619,7 @@ impl<T: Send> Sender<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Clone for Sender<T> {
+impl<T> Clone for Sender<T> {
     fn clone(&self) -> Sender<T> {
         let (packet, sleeper, guard) = match *unsafe { self.inner() } {
             Flavor::Oneshot(ref p) => {
@@ -665,7 +665,7 @@ 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> Drop for Sender<T> {
     fn drop(&mut self) {
         match *unsafe { self.inner_mut() } {
             Flavor::Oneshot(ref mut p) => unsafe { (*p.get()).drop_chan(); },
@@ -680,7 +680,7 @@ impl<T: Send> Drop for Sender<T> {
 // SyncSender
 ////////////////////////////////////////////////////////////////////////////////
 
-impl<T: Send> SyncSender<T> {
+impl<T> SyncSender<T> {
     fn new(inner: Arc<UnsafeCell<sync::Packet<T>>>) -> SyncSender<T> {
         SyncSender { inner: inner }
     }
@@ -720,7 +720,7 @@ impl<T: Send> SyncSender<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Clone for SyncSender<T> {
+impl<T> Clone for SyncSender<T> {
     fn clone(&self) -> SyncSender<T> {
         unsafe { (*self.inner.get()).clone_chan(); }
         return SyncSender::new(self.inner.clone());
@@ -729,7 +729,7 @@ 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> Drop for SyncSender<T> {
     fn drop(&mut self) {
         unsafe { (*self.inner.get()).drop_chan(); }
     }
@@ -739,7 +739,7 @@ impl<T: Send> Drop for SyncSender<T> {
 // Receiver
 ////////////////////////////////////////////////////////////////////////////////
 
-impl<T: Send> Receiver<T> {
+impl<T> Receiver<T> {
     fn new(inner: Flavor<T>) -> Receiver<T> {
         Receiver { inner: UnsafeCell::new(inner) }
     }
@@ -858,7 +858,7 @@ impl<T: Send> Receiver<T> {
     }
 }
 
-impl<T: Send> select::Packet for Receiver<T> {
+impl<T> select::Packet for Receiver<T> {
     fn can_recv(&self) -> bool {
         loop {
             let new_port = match *unsafe { self.inner() } {
@@ -945,7 +945,7 @@ 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> Iterator for Iter<'a, T> {
     type Item = T;
 
     fn next(&mut self) -> Option<T> { self.rx.recv().ok() }
@@ -953,7 +953,7 @@ impl<'a, T: Send> Iterator for Iter<'a, T> {
 
 #[unsafe_destructor]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Drop for Receiver<T> {
+impl<T> Drop for Receiver<T> {
     fn drop(&mut self) {
         match *unsafe { self.inner_mut() } {
             Flavor::Oneshot(ref mut p) => unsafe { (*p.get()).drop_port(); },
diff --git a/src/libstd/sync/mpsc/mpsc_queue.rs b/src/libstd/sync/mpsc/mpsc_queue.rs
index 1be8b0dd862..9b6c8f4dd97 100644
--- a/src/libstd/sync/mpsc/mpsc_queue.rs
+++ b/src/libstd/sync/mpsc/mpsc_queue.rs
@@ -72,12 +72,12 @@ struct Node<T> {
 /// The multi-producer single-consumer structure. This is not cloneable, but it
 /// may be safely shared so long as it is guaranteed that there is only one
 /// popper at a time (many pushers are allowed).
-pub struct Queue<T: Send> {
+pub struct Queue<T> {
     head: AtomicPtr<Node<T>>,
     tail: UnsafeCell<*mut Node<T>>,
 }
 
-unsafe impl<T:Send> Send for Queue<T> { }
+unsafe impl<T: Send> Send for Queue<T> { }
 unsafe impl<T: Send> Sync for Queue<T> { }
 
 impl<T> Node<T> {
@@ -89,7 +89,7 @@ impl<T> Node<T> {
     }
 }
 
-impl<T: Send> Queue<T> {
+impl<T> 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> Drop for Queue<T> {
     fn drop(&mut self) {
         unsafe {
             let mut cur = *self.tail.get();
diff --git a/src/libstd/sync/mpsc/oneshot.rs b/src/libstd/sync/mpsc/oneshot.rs
index 13578ce0517..c6e8d87a22e 100644
--- a/src/libstd/sync/mpsc/oneshot.rs
+++ b/src/libstd/sync/mpsc/oneshot.rs
@@ -54,7 +54,7 @@ const DISCONNECTED: usize = 2;   // channel is disconnected OR upgraded
 // moves *from* a pointer, ownership of the token is transferred to
 // whoever changed the state.
 
-pub struct Packet<T:Send> {
+pub struct Packet<T> {
     // Internal state of the chan/port pair (stores the blocked task as well)
     state: AtomicUsize,
     // One-shot data slot location
@@ -64,7 +64,7 @@ pub struct Packet<T:Send> {
     upgrade: MyUpgrade<T>,
 }
 
-pub enum Failure<T:Send> {
+pub enum Failure<T> {
     Empty,
     Disconnected,
     Upgraded(Receiver<T>),
@@ -76,19 +76,19 @@ pub enum UpgradeResult {
     UpWoke(SignalToken),
 }
 
-pub enum SelectionResult<T:Send> {
+pub enum SelectionResult<T> {
     SelCanceled,
     SelUpgraded(SignalToken, Receiver<T>),
     SelSuccess,
 }
 
-enum MyUpgrade<T:Send> {
+enum MyUpgrade<T> {
     NothingSent,
     SendUsed,
     GoUp(Receiver<T>),
 }
 
-impl<T: Send> Packet<T> {
+impl<T> 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> Drop for Packet<T> {
     fn drop(&mut self) {
         assert_eq!(self.state.load(Ordering::SeqCst), DISCONNECTED);
     }
diff --git a/src/libstd/sync/mpsc/shared.rs b/src/libstd/sync/mpsc/shared.rs
index 80cbd076163..5c1610bdc31 100644
--- a/src/libstd/sync/mpsc/shared.rs
+++ b/src/libstd/sync/mpsc/shared.rs
@@ -40,7 +40,7 @@ const MAX_STEALS: isize = 5;
 #[cfg(not(test))]
 const MAX_STEALS: isize = 1 << 20;
 
-pub struct Packet<T: Send> {
+pub struct Packet<T> {
     queue: mpsc::Queue<T>,
     cnt: AtomicIsize, // How many items are on this channel
     steals: isize, // How many times has a port received without blocking?
@@ -64,7 +64,7 @@ pub enum Failure {
     Disconnected,
 }
 
-impl<T: Send> Packet<T> {
+impl<T> Packet<T> {
     // Creation of a packet *must* be followed by a call to postinit_lock
     // and later by inherit_blocker
     pub fn new() -> Packet<T> {
@@ -474,7 +474,7 @@ impl<T: Send> Packet<T> {
 }
 
 #[unsafe_destructor]
-impl<T: Send> Drop for Packet<T> {
+impl<T> Drop for Packet<T> {
     fn drop(&mut self) {
         // Note that this load is not only an assert for correctness about
         // disconnection, but also a proper fence before the read of
diff --git a/src/libstd/sync/mpsc/spsc_queue.rs b/src/libstd/sync/mpsc/spsc_queue.rs
index cd6d1ee05c7..c75ac130808 100644
--- a/src/libstd/sync/mpsc/spsc_queue.rs
+++ b/src/libstd/sync/mpsc/spsc_queue.rs
@@ -57,7 +57,7 @@ struct Node<T> {
 /// but it can be safely shared in an Arc if it is guaranteed that there
 /// is only one popper and one pusher touching the queue at any one point in
 /// time.
-pub struct Queue<T: Send> {
+pub struct Queue<T> {
     // consumer fields
     tail: UnsafeCell<*mut Node<T>>, // where to pop from
     tail_prev: AtomicPtr<Node<T>>, // where to pop from
@@ -78,7 +78,7 @@ unsafe impl<T: Send> Send for Queue<T> { }
 
 unsafe impl<T: Send> Sync for Queue<T> { }
 
-impl<T: Send> Node<T> {
+impl<T> Node<T> {
     fn new() -> *mut Node<T> {
         unsafe {
             boxed::into_raw(box Node {
@@ -89,7 +89,7 @@ impl<T: Send> Node<T> {
     }
 }
 
-impl<T: Send> Queue<T> {
+impl<T> Queue<T> {
     /// Creates a new queue.
     ///
     /// This is unsafe as the type system doesn't enforce a single
@@ -227,7 +227,7 @@ impl<T: Send> Queue<T> {
 }
 
 #[unsafe_destructor]
-impl<T: Send> Drop for Queue<T> {
+impl<T> Drop for Queue<T> {
     fn drop(&mut self) {
         unsafe {
             let mut cur = *self.first.get();
diff --git a/src/libstd/sync/mpsc/stream.rs b/src/libstd/sync/mpsc/stream.rs
index a5a73314a6d..f0363fae84f 100644
--- a/src/libstd/sync/mpsc/stream.rs
+++ b/src/libstd/sync/mpsc/stream.rs
@@ -39,7 +39,7 @@ const MAX_STEALS: isize = 5;
 #[cfg(not(test))]
 const MAX_STEALS: isize = 1 << 20;
 
-pub struct Packet<T:Send> {
+pub struct Packet<T> {
     queue: spsc::Queue<Message<T>>, // internal queue for all message
 
     cnt: AtomicIsize, // How many items are on this channel
@@ -49,7 +49,7 @@ pub struct Packet<T:Send> {
     port_dropped: AtomicBool, // flag if the channel has been destroyed.
 }
 
-pub enum Failure<T:Send> {
+pub enum Failure<T> {
     Empty,
     Disconnected,
     Upgraded(Receiver<T>),
@@ -61,7 +61,7 @@ pub enum UpgradeResult {
     UpWoke(SignalToken),
 }
 
-pub enum SelectionResult<T:Send> {
+pub enum SelectionResult<T> {
     SelSuccess,
     SelCanceled,
     SelUpgraded(SignalToken, Receiver<T>),
@@ -69,12 +69,12 @@ pub enum SelectionResult<T:Send> {
 
 // Any message could contain an "upgrade request" to a new shared port, so the
 // internal queue it's a queue of T, but rather Message<T>
-enum Message<T:Send> {
+enum Message<T> {
     Data(T),
     GoUp(Receiver<T>),
 }
 
-impl<T: Send> Packet<T> {
+impl<T> Packet<T> {
     pub fn new() -> Packet<T> {
         Packet {
             queue: unsafe { spsc::Queue::new(128) },
@@ -472,7 +472,7 @@ impl<T: Send> Packet<T> {
 }
 
 #[unsafe_destructor]
-impl<T: Send> Drop for Packet<T> {
+impl<T> Drop for Packet<T> {
     fn drop(&mut self) {
         // Note that this load is not only an assert for correctness about
         // disconnection, but also a proper fence before the read of
diff --git a/src/libstd/sync/mpsc/sync.rs b/src/libstd/sync/mpsc/sync.rs
index 71236269487..6221ca59b54 100644
--- a/src/libstd/sync/mpsc/sync.rs
+++ b/src/libstd/sync/mpsc/sync.rs
@@ -47,7 +47,7 @@ use sync::mpsc::blocking::{self, WaitToken, SignalToken};
 use sync::mpsc::select::StartResult::{self, Installed, Abort};
 use sync::{Mutex, MutexGuard};
 
-pub struct Packet<T: Send> {
+pub struct Packet<T> {
     /// Only field outside of the mutex. Just done for kicks, but mainly because
     /// the other shared channel already had the code implemented
     channels: AtomicUsize,
@@ -113,10 +113,10 @@ pub enum Failure {
 
 /// Atomically blocks the current thread, placing it into `slot`, unlocking `lock`
 /// in the meantime. This re-locks the mutex upon returning.
-fn wait<'a, 'b, T: Send>(lock: &'a Mutex<State<T>>,
-                         mut guard: MutexGuard<'b, State<T>>,
-                         f: fn(SignalToken) -> Blocker)
-                         -> MutexGuard<'a, State<T>>
+fn wait<'a, 'b, T>(lock: &'a Mutex<State<T>>,
+                   mut guard: MutexGuard<'b, State<T>>,
+                   f: fn(SignalToken) -> Blocker)
+                   -> MutexGuard<'a, State<T>>
 {
     let (wait_token, signal_token) = blocking::tokens();
     match mem::replace(&mut guard.blocker, f(signal_token)) {
@@ -136,7 +136,7 @@ fn wakeup<T>(token: SignalToken, guard: MutexGuard<State<T>>) {
     token.signal();
 }
 
-impl<T: Send> Packet<T> {
+impl<T> Packet<T> {
     pub fn new(cap: usize) -> Packet<T> {
         Packet {
             channels: AtomicUsize::new(1),
@@ -412,7 +412,7 @@ impl<T: Send> Packet<T> {
 }
 
 #[unsafe_destructor]
-impl<T: Send> Drop for Packet<T> {
+impl<T> Drop for Packet<T> {
     fn drop(&mut self) {
         assert_eq!(self.channels.load(Ordering::SeqCst), 0);
         let mut guard = self.lock.lock().unwrap();
diff --git a/src/libstd/sync/mutex.rs b/src/libstd/sync/mutex.rs
index b24cfbb6899..16e7f265412 100644
--- a/src/libstd/sync/mutex.rs
+++ b/src/libstd/sync/mutex.rs
@@ -112,7 +112,7 @@ use fmt;
 /// *guard += 1;
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-pub struct Mutex<T: Send> {
+pub struct Mutex<T> {
     // Note that this static mutex is in a *box*, not inlined into the struct
     // itself. Once a native mutex has been used once, its address can never
     // change (it can't be moved). This mutex type can be safely moved at any
@@ -122,6 +122,8 @@ pub struct Mutex<T: Send> {
     data: UnsafeCell<T>,
 }
 
+// these are the only places where `T: Send` matters; all other
+// functionality works fine on a single thread.
 unsafe impl<T: Send> Send for Mutex<T> { }
 
 unsafe impl<T: Send> Sync for Mutex<T> { }
@@ -181,7 +183,7 @@ pub const MUTEX_INIT: StaticMutex = StaticMutex {
     poison: poison::FLAG_INIT,
 };
 
-impl<T: Send> Mutex<T> {
+impl<T> Mutex<T> {
     /// Creates a new mutex in an unlocked state ready for use.
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new(t: T) -> Mutex<T> {
@@ -244,7 +246,7 @@ impl<T: Send> Mutex<T> {
 
 #[unsafe_destructor]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> Drop for Mutex<T> {
+impl<T> Drop for Mutex<T> {
     fn drop(&mut self) {
         // This is actually safe b/c we know that there is no further usage of
         // this mutex (it's up to the user to arrange for a mutex to get
@@ -254,7 +256,7 @@ impl<T: Send> Drop for Mutex<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: fmt::Debug + Send + 'static> fmt::Debug for Mutex<T> {
+impl<T: fmt::Debug + 'static> fmt::Debug for Mutex<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self.try_lock() {
             Ok(guard) => write!(f, "Mutex {{ data: {:?} }}", *guard),
diff --git a/src/libstd/sync/rwlock.rs b/src/libstd/sync/rwlock.rs
index a79ffaa0860..d70350bc7d6 100644
--- a/src/libstd/sync/rwlock.rs
+++ b/src/libstd/sync/rwlock.rs
@@ -130,7 +130,7 @@ pub struct RwLockWriteGuard<'a, T: 'a> {
 
 impl<'a, T> !marker::Send for RwLockWriteGuard<'a, T> {}
 
-impl<T: Send + Sync> RwLock<T> {
+impl<T> RwLock<T> {
     /// Creates a new instance of an `RwLock<T>` which is unlocked.
     ///
     /// # Examples
@@ -258,7 +258,7 @@ impl<T> Drop for RwLock<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: fmt::Debug + Send + Sync> fmt::Debug for RwLock<T> {
+impl<T: fmt::Debug> fmt::Debug for RwLock<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self.try_read() {
             Ok(guard) => write!(f, "RwLock {{ data: {:?} }}", *guard),