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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:20:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:20:29 +0000
commit631cd5845e8de329d0e227aaa707d7ea228b8f8f (patch)
treea1b87c8f8cad01cf18f7c5f57a08f102771ed303 /library/std/src/sync
parentAdding debian version 1.69.0+dfsg1-1. (diff)
downloadrustc-631cd5845e8de329d0e227aaa707d7ea228b8f8f.tar.xz
rustc-631cd5845e8de329d0e227aaa707d7ea228b8f8f.zip
Merging upstream version 1.70.0+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/std/src/sync')
-rw-r--r--library/std/src/sync/lazy_lock.rs24
-rw-r--r--library/std/src/sync/mod.rs9
-rw-r--r--library/std/src/sync/mpmc/array.rs107
-rw-r--r--library/std/src/sync/mpmc/list.rs12
-rw-r--r--library/std/src/sync/mpmc/mod.rs4
-rw-r--r--library/std/src/sync/mpsc/sync_tests.rs13
-rw-r--r--library/std/src/sync/mutex.rs24
-rw-r--r--library/std/src/sync/once_lock.rs59
-rw-r--r--library/std/src/sync/remutex.rs2
9 files changed, 168 insertions, 86 deletions
diff --git a/library/std/src/sync/lazy_lock.rs b/library/std/src/sync/lazy_lock.rs
index 7e85d6a06..8e9ea293c 100644
--- a/library/std/src/sync/lazy_lock.rs
+++ b/library/std/src/sync/lazy_lock.rs
@@ -26,7 +26,7 @@ union Data<T, F> {
/// # Examples
///
/// ```
-/// #![feature(once_cell)]
+/// #![feature(lazy_cell)]
///
/// use std::collections::HashMap;
///
@@ -54,7 +54,7 @@ union Data<T, F> {
/// // Some("Hoyten")
/// }
/// ```
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
pub struct LazyLock<T, F = fn() -> T> {
once: Once,
data: UnsafeCell<Data<T, F>>,
@@ -64,7 +64,7 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> {
/// Creates a new lazy value with the given initializing
/// function.
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[unstable(feature = "lazy_cell", issue = "109736")]
pub const fn new(f: F) -> LazyLock<T, F> {
LazyLock { once: Once::new(), data: UnsafeCell::new(Data { f: ManuallyDrop::new(f) }) }
}
@@ -76,7 +76,7 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> {
/// # Examples
///
/// ```
- /// #![feature(once_cell)]
+ /// #![feature(lazy_cell)]
///
/// use std::sync::LazyLock;
///
@@ -86,7 +86,7 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> {
/// assert_eq!(&*lazy, &92);
/// ```
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[unstable(feature = "lazy_cell", issue = "109736")]
pub fn force(this: &LazyLock<T, F>) -> &T {
this.once.call_once(|| {
// SAFETY: `call_once` only runs this closure once, ever.
@@ -122,7 +122,7 @@ impl<T, F> LazyLock<T, F> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
impl<T, F> Drop for LazyLock<T, F> {
fn drop(&mut self) {
match self.once.state() {
@@ -135,7 +135,7 @@ impl<T, F> Drop for LazyLock<T, F> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
impl<T, F: FnOnce() -> T> Deref for LazyLock<T, F> {
type Target = T;
@@ -145,7 +145,7 @@ impl<T, F: FnOnce() -> T> Deref for LazyLock<T, F> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
impl<T: Default> Default for LazyLock<T> {
/// Creates a new lazy value using `Default` as the initializing function.
#[inline]
@@ -154,7 +154,7 @@ impl<T: Default> Default for LazyLock<T> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
impl<T: fmt::Debug, F> fmt::Debug for LazyLock<T, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self.get() {
@@ -166,13 +166,13 @@ impl<T: fmt::Debug, F> fmt::Debug for LazyLock<T, F> {
// We never create a `&F` from a `&LazyLock<T, F>` so it is fine
// to not impl `Sync` for `F`
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
unsafe impl<T: Sync + Send, F: Send> Sync for LazyLock<T, F> {}
// auto-derived `Send` impl is OK.
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
impl<T: RefUnwindSafe + UnwindSafe, F: UnwindSafe> RefUnwindSafe for LazyLock<T, F> {}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
impl<T: UnwindSafe, F: UnwindSafe> UnwindSafe for LazyLock<T, F> {}
#[cfg(test)]
diff --git a/library/std/src/sync/mod.rs b/library/std/src/sync/mod.rs
index 4edc95617..f6a7c0a9f 100644
--- a/library/std/src/sync/mod.rs
+++ b/library/std/src/sync/mod.rs
@@ -133,7 +133,9 @@
//! - [`Mutex`]: Mutual Exclusion mechanism, which ensures that at
//! most one thread at a time is able to access some data.
//!
-//! - [`Once`]: Used for thread-safe, one-time initialization of a
+//! - [`Once`]: Used for a thread-safe, one-time global initialization routine
+//!
+//! - [`OnceLock`]: Used for thread-safe, one-time initialization of a
//! global variable.
//!
//! - [`RwLock`]: Provides a mutual exclusion mechanism which allows
@@ -147,6 +149,7 @@
//! [`mpsc`]: crate::sync::mpsc
//! [`Mutex`]: crate::sync::Mutex
//! [`Once`]: crate::sync::Once
+//! [`OnceLock`]: crate::sync::OnceLock
//! [`RwLock`]: crate::sync::RwLock
#![stable(feature = "rust1", since = "1.0.0")]
@@ -172,9 +175,9 @@ pub use self::poison::{LockResult, PoisonError, TryLockError, TryLockResult};
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::rwlock::{RwLock, RwLockReadGuard, RwLockWriteGuard};
-#[unstable(feature = "once_cell", issue = "74465")]
+#[unstable(feature = "lazy_cell", issue = "109736")]
pub use self::lazy_lock::LazyLock;
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
pub use self::once_lock::OnceLock;
pub(crate) use self::remutex::{ReentrantMutex, ReentrantMutexGuard};
diff --git a/library/std/src/sync/mpmc/array.rs b/library/std/src/sync/mpmc/array.rs
index c6bb09b04..492e21d9b 100644
--- a/library/std/src/sync/mpmc/array.rs
+++ b/library/std/src/sync/mpmc/array.rs
@@ -25,7 +25,8 @@ struct Slot<T> {
/// The current stamp.
stamp: AtomicUsize,
- /// The message in this slot.
+ /// The message in this slot. Either read out in `read` or dropped through
+ /// `discard_all_messages`.
msg: UnsafeCell<MaybeUninit<T>>,
}
@@ -439,14 +440,13 @@ impl<T> Channel<T> {
Some(self.cap)
}
- /// Disconnects the channel and wakes up all blocked senders and receivers.
+ /// Disconnects senders and wakes up all blocked receivers.
///
/// Returns `true` if this call disconnected the channel.
- pub(crate) fn disconnect(&self) -> bool {
+ pub(crate) fn disconnect_senders(&self) -> bool {
let tail = self.tail.fetch_or(self.mark_bit, Ordering::SeqCst);
if tail & self.mark_bit == 0 {
- self.senders.disconnect();
self.receivers.disconnect();
true
} else {
@@ -454,6 +454,85 @@ impl<T> Channel<T> {
}
}
+ /// Disconnects receivers and wakes up all blocked senders.
+ ///
+ /// Returns `true` if this call disconnected the channel.
+ ///
+ /// # Safety
+ /// May only be called once upon dropping the last receiver. The
+ /// destruction of all other receivers must have been observed with acquire
+ /// ordering or stronger.
+ pub(crate) unsafe fn disconnect_receivers(&self) -> bool {
+ let tail = self.tail.fetch_or(self.mark_bit, Ordering::SeqCst);
+ let disconnected = if tail & self.mark_bit == 0 {
+ self.senders.disconnect();
+ true
+ } else {
+ false
+ };
+
+ self.discard_all_messages(tail);
+ disconnected
+ }
+
+ /// Discards all messages.
+ ///
+ /// `tail` should be the current (and therefore last) value of `tail`.
+ ///
+ /// # Panicking
+ /// If a destructor panics, the remaining messages are leaked, matching the
+ /// behaviour of the unbounded channel.
+ ///
+ /// # Safety
+ /// This method must only be called when dropping the last receiver. The
+ /// destruction of all other receivers must have been observed with acquire
+ /// ordering or stronger.
+ unsafe fn discard_all_messages(&self, tail: usize) {
+ debug_assert!(self.is_disconnected());
+
+ // Only receivers modify `head`, so since we are the last one,
+ // this value will not change and will not be observed (since
+ // no new messages can be sent after disconnection).
+ let mut head = self.head.load(Ordering::Relaxed);
+ let tail = tail & !self.mark_bit;
+
+ let backoff = Backoff::new();
+ loop {
+ // Deconstruct the head.
+ let index = head & (self.mark_bit - 1);
+ let lap = head & !(self.one_lap - 1);
+
+ // Inspect the corresponding slot.
+ debug_assert!(index < self.buffer.len());
+ let slot = unsafe { self.buffer.get_unchecked(index) };
+ let stamp = slot.stamp.load(Ordering::Acquire);
+
+ // If the stamp is ahead of the head by 1, we may drop the message.
+ if head + 1 == stamp {
+ head = if index + 1 < self.cap {
+ // Same lap, incremented index.
+ // Set to `{ lap: lap, mark: 0, index: index + 1 }`.
+ head + 1
+ } else {
+ // One lap forward, index wraps around to zero.
+ // Set to `{ lap: lap.wrapping_add(1), mark: 0, index: 0 }`.
+ lap.wrapping_add(self.one_lap)
+ };
+
+ unsafe {
+ (*slot.msg.get()).assume_init_drop();
+ }
+ // If the tail equals the head, that means the channel is empty.
+ } else if tail == head {
+ return;
+ // Otherwise, a sender is about to write into the slot, so we need
+ // to wait for it to update the stamp.
+ } else {
+ backoff.spin_heavy();
+ }
+ }
+ }
+
/// Returns `true` if the channel is disconnected.
pub(crate) fn is_disconnected(&self) -> bool {
self.tail.load(Ordering::SeqCst) & self.mark_bit != 0
@@ -483,23 +562,3 @@ impl<T> Channel<T> {
head.wrapping_add(self.one_lap) == tail & !self.mark_bit
}
}
-
-impl<T> Drop for Channel<T> {
- fn drop(&mut self) {
- // Get the index of the head.
- let hix = self.head.load(Ordering::Relaxed) & (self.mark_bit - 1);
-
- // Loop over all slots that hold a message and drop them.
- for i in 0..self.len() {
- // Compute the index of the next slot holding a message.
- let index = if hix + i < self.cap { hix + i } else { hix + i - self.cap };
-
- unsafe {
- debug_assert!(index < self.buffer.len());
- let slot = self.buffer.get_unchecked_mut(index);
- let msg = &mut *slot.msg.get();
- msg.as_mut_ptr().drop_in_place();
- }
- }
- }
-}
diff --git a/library/std/src/sync/mpmc/list.rs b/library/std/src/sync/mpmc/list.rs
index ec6c0726a..406a331a3 100644
--- a/library/std/src/sync/mpmc/list.rs
+++ b/library/std/src/sync/mpmc/list.rs
@@ -549,6 +549,18 @@ impl<T> Channel<T> {
let mut head = self.head.index.load(Ordering::Acquire);
let mut block = self.head.block.load(Ordering::Acquire);
+ // If we're going to be dropping messages we need to synchronize with initialization
+ if head >> SHIFT != tail >> SHIFT {
+ // The block can be null here only if a sender is in the process of initializing the
+ // channel while another sender managed to send a message by inserting it into the
+ // semi-initialized channel and advanced the tail.
+ // In that case, just wait until it gets initialized.
+ while block.is_null() {
+ backoff.spin_heavy();
+ block = self.head.block.load(Ordering::Acquire);
+ }
+ }
+
unsafe {
// Drop all messages between head and tail and deallocate the heap-allocated blocks.
while head >> SHIFT != tail >> SHIFT {
diff --git a/library/std/src/sync/mpmc/mod.rs b/library/std/src/sync/mpmc/mod.rs
index 7a602cecd..2068dda39 100644
--- a/library/std/src/sync/mpmc/mod.rs
+++ b/library/std/src/sync/mpmc/mod.rs
@@ -227,7 +227,7 @@ impl<T> Drop for Sender<T> {
fn drop(&mut self) {
unsafe {
match &self.flavor {
- SenderFlavor::Array(chan) => chan.release(|c| c.disconnect()),
+ SenderFlavor::Array(chan) => chan.release(|c| c.disconnect_senders()),
SenderFlavor::List(chan) => chan.release(|c| c.disconnect_senders()),
SenderFlavor::Zero(chan) => chan.release(|c| c.disconnect()),
}
@@ -403,7 +403,7 @@ impl<T> Drop for Receiver<T> {
fn drop(&mut self) {
unsafe {
match &self.flavor {
- ReceiverFlavor::Array(chan) => chan.release(|c| c.disconnect()),
+ ReceiverFlavor::Array(chan) => chan.release(|c| c.disconnect_receivers()),
ReceiverFlavor::List(chan) => chan.release(|c| c.disconnect_receivers()),
ReceiverFlavor::Zero(chan) => chan.release(|c| c.disconnect()),
}
diff --git a/library/std/src/sync/mpsc/sync_tests.rs b/library/std/src/sync/mpsc/sync_tests.rs
index 9d2f92ffc..632709fd9 100644
--- a/library/std/src/sync/mpsc/sync_tests.rs
+++ b/library/std/src/sync/mpsc/sync_tests.rs
@@ -1,5 +1,6 @@
use super::*;
use crate::env;
+use crate::rc::Rc;
use crate::sync::mpmc::SendTimeoutError;
use crate::thread;
use crate::time::Duration;
@@ -656,3 +657,15 @@ fn issue_15761() {
repro()
}
}
+
+#[test]
+fn drop_unreceived() {
+ let (tx, rx) = sync_channel::<Rc<()>>(1);
+ let msg = Rc::new(());
+ let weak = Rc::downgrade(&msg);
+ assert!(tx.send(msg).is_ok());
+ drop(rx);
+ // Messages should be dropped immediately when the last receiver is destroyed.
+ assert!(weak.upgrade().is_none());
+ drop(tx);
+}
diff --git a/library/std/src/sync/mutex.rs b/library/std/src/sync/mutex.rs
index 065045f44..b8fec6902 100644
--- a/library/std/src/sync/mutex.rs
+++ b/library/std/src/sync/mutex.rs
@@ -107,8 +107,8 @@ use crate::sys::locks as sys;
/// *guard += 1;
/// ```
///
-/// It is sometimes necessary to manually drop the mutex guard to unlock it
-/// sooner than the end of the enclosing scope.
+/// To unlock a mutex guard sooner than the end of the enclosing scope,
+/// either create an inner scope or drop the guard manually.
///
/// ```
/// use std::sync::{Arc, Mutex};
@@ -125,11 +125,18 @@ use crate::sys::locks as sys;
/// let res_mutex_clone = Arc::clone(&res_mutex);
///
/// threads.push(thread::spawn(move || {
-/// let mut data = data_mutex_clone.lock().unwrap();
-/// // This is the result of some important and long-ish work.
-/// let result = data.iter().fold(0, |acc, x| acc + x * 2);
-/// data.push(result);
-/// drop(data);
+/// // Here we use a block to limit the lifetime of the lock guard.
+/// let result = {
+/// let mut data = data_mutex_clone.lock().unwrap();
+/// // This is the result of some important and long-ish work.
+/// let result = data.iter().fold(0, |acc, x| acc + x * 2);
+/// data.push(result);
+/// result
+/// // The mutex guard gets dropped here, together with any other values
+/// // created in the critical section.
+/// };
+/// // The guard created here is a temporary dropped at the end of the statement, i.e.
+/// // the lock would not remain being held even if the thread did some additional work.
/// *res_mutex_clone.lock().unwrap() += result;
/// }));
/// });
@@ -146,6 +153,8 @@ use crate::sys::locks as sys;
/// // It's even more important here than in the threads because we `.join` the
/// // threads after that. If we had not dropped the mutex guard, a thread could
/// // be waiting forever for it, causing a deadlock.
+/// // As in the threads, a block could have been used instead of calling the
+/// // `drop` function.
/// drop(data);
/// // Here the mutex guard is not assigned to a variable and so, even if the
/// // scope does not end after this line, the mutex is still released: there is
@@ -160,6 +169,7 @@ use crate::sys::locks as sys;
///
/// assert_eq!(*res_mutex.lock().unwrap(), 800);
/// ```
+///
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "Mutex")]
pub struct Mutex<T: ?Sized> {
diff --git a/library/std/src/sync/once_lock.rs b/library/std/src/sync/once_lock.rs
index ed339ca5d..ab25a5bcc 100644
--- a/library/std/src/sync/once_lock.rs
+++ b/library/std/src/sync/once_lock.rs
@@ -14,8 +14,6 @@ use crate::sync::Once;
/// # Examples
///
/// ```
-/// #![feature(once_cell)]
-///
/// use std::sync::OnceLock;
///
/// static CELL: OnceLock<String> = OnceLock::new();
@@ -32,7 +30,7 @@ use crate::sync::Once;
/// assert!(value.is_some());
/// assert_eq!(value.unwrap().as_str(), "Hello, World!");
/// ```
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
pub struct OnceLock<T> {
once: Once,
// Whether or not the value is initialized is tracked by `once.is_completed()`.
@@ -40,8 +38,6 @@ pub struct OnceLock<T> {
/// `PhantomData` to make sure dropck understands we're dropping T in our Drop impl.
///
/// ```compile_fail,E0597
- /// #![feature(once_cell)]
- ///
/// use std::sync::OnceLock;
///
/// struct A<'a>(&'a str);
@@ -63,7 +59,8 @@ impl<T> OnceLock<T> {
/// Creates a new empty cell.
#[inline]
#[must_use]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[stable(feature = "once_cell", since = "1.70.0")]
+ #[rustc_const_stable(feature = "once_cell", since = "1.70.0")]
pub const fn new() -> OnceLock<T> {
OnceLock {
once: Once::new(),
@@ -77,7 +74,7 @@ impl<T> OnceLock<T> {
/// Returns `None` if the cell is empty, or being initialized. This
/// method never blocks.
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[stable(feature = "once_cell", since = "1.70.0")]
pub fn get(&self) -> Option<&T> {
if self.is_initialized() {
// Safe b/c checked is_initialized
@@ -91,7 +88,7 @@ impl<T> OnceLock<T> {
///
/// Returns `None` if the cell is empty. This method never blocks.
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[stable(feature = "once_cell", since = "1.70.0")]
pub fn get_mut(&mut self) -> Option<&mut T> {
if self.is_initialized() {
// Safe b/c checked is_initialized and we have a unique access
@@ -111,8 +108,6 @@ impl<T> OnceLock<T> {
/// # Examples
///
/// ```
- /// #![feature(once_cell)]
- ///
/// use std::sync::OnceLock;
///
/// static CELL: OnceLock<i32> = OnceLock::new();
@@ -129,7 +124,7 @@ impl<T> OnceLock<T> {
/// }
/// ```
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[stable(feature = "once_cell", since = "1.70.0")]
pub fn set(&self, value: T) -> Result<(), T> {
let mut value = Some(value);
self.get_or_init(|| value.take().unwrap());
@@ -158,8 +153,6 @@ impl<T> OnceLock<T> {
/// # Examples
///
/// ```
- /// #![feature(once_cell)]
- ///
/// use std::sync::OnceLock;
///
/// let cell = OnceLock::new();
@@ -169,7 +162,7 @@ impl<T> OnceLock<T> {
/// assert_eq!(value, &92);
/// ```
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[stable(feature = "once_cell", since = "1.70.0")]
pub fn get_or_init<F>(&self, f: F) -> &T
where
F: FnOnce() -> T,
@@ -195,7 +188,7 @@ impl<T> OnceLock<T> {
/// # Examples
///
/// ```
- /// #![feature(once_cell)]
+ /// #![feature(once_cell_try)]
///
/// use std::sync::OnceLock;
///
@@ -209,7 +202,7 @@ impl<T> OnceLock<T> {
/// assert_eq!(cell.get(), Some(&92))
/// ```
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[unstable(feature = "once_cell_try", issue = "109737")]
pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>
where
F: FnOnce() -> Result<T, E>,
@@ -236,8 +229,6 @@ impl<T> OnceLock<T> {
/// # Examples
///
/// ```
- /// #![feature(once_cell)]
- ///
/// use std::sync::OnceLock;
///
/// let cell: OnceLock<String> = OnceLock::new();
@@ -248,7 +239,7 @@ impl<T> OnceLock<T> {
/// assert_eq!(cell.into_inner(), Some("hello".to_string()));
/// ```
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[stable(feature = "once_cell", since = "1.70.0")]
pub fn into_inner(mut self) -> Option<T> {
self.take()
}
@@ -262,8 +253,6 @@ impl<T> OnceLock<T> {
/// # Examples
///
/// ```
- /// #![feature(once_cell)]
- ///
/// use std::sync::OnceLock;
///
/// let mut cell: OnceLock<String> = OnceLock::new();
@@ -275,7 +264,7 @@ impl<T> OnceLock<T> {
/// assert_eq!(cell.get(), None);
/// ```
#[inline]
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[stable(feature = "once_cell", since = "1.70.0")]
pub fn take(&mut self) -> Option<T> {
if self.is_initialized() {
self.once = Once::new();
@@ -344,17 +333,17 @@ impl<T> OnceLock<T> {
// scoped thread B, which fills the cell, which is
// then destroyed by A. That is, destructor observes
// a sent value.
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
unsafe impl<T: Sync + Send> Sync for OnceLock<T> {}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
unsafe impl<T: Send> Send for OnceLock<T> {}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceLock<T> {}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
impl<T: UnwindSafe> UnwindSafe for OnceLock<T> {}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
impl<T> const Default for OnceLock<T> {
/// Creates a new empty cell.
@@ -362,8 +351,6 @@ impl<T> const Default for OnceLock<T> {
/// # Example
///
/// ```
- /// #![feature(once_cell)]
- ///
/// use std::sync::OnceLock;
///
/// fn main() {
@@ -376,7 +363,7 @@ impl<T> const Default for OnceLock<T> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
impl<T: fmt::Debug> fmt::Debug for OnceLock<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self.get() {
@@ -386,7 +373,7 @@ impl<T: fmt::Debug> fmt::Debug for OnceLock<T> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
impl<T: Clone> Clone for OnceLock<T> {
#[inline]
fn clone(&self) -> OnceLock<T> {
@@ -401,15 +388,13 @@ impl<T: Clone> Clone for OnceLock<T> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
impl<T> From<T> for OnceLock<T> {
/// Create a new cell with its contents set to `value`.
///
/// # Example
///
/// ```
- /// #![feature(once_cell)]
- ///
/// use std::sync::OnceLock;
///
/// # fn main() -> Result<(), i32> {
@@ -430,7 +415,7 @@ impl<T> From<T> for OnceLock<T> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
impl<T: PartialEq> PartialEq for OnceLock<T> {
#[inline]
fn eq(&self, other: &OnceLock<T>) -> bool {
@@ -438,10 +423,10 @@ impl<T: PartialEq> PartialEq for OnceLock<T> {
}
}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
impl<T: Eq> Eq for OnceLock<T> {}
-#[unstable(feature = "once_cell", issue = "74465")]
+#[stable(feature = "once_cell", since = "1.70.0")]
unsafe impl<#[may_dangle] T> Drop for OnceLock<T> {
#[inline]
fn drop(&mut self) {
diff --git a/library/std/src/sync/remutex.rs b/library/std/src/sync/remutex.rs
index 4c054da64..519ec2c32 100644
--- a/library/std/src/sync/remutex.rs
+++ b/library/std/src/sync/remutex.rs
@@ -35,7 +35,7 @@ use crate::sys::locks as sys;
/// `owner` can be checked by other threads that want to see if they already
/// hold the lock, so needs to be atomic. If it compares equal, we're on the
/// same thread that holds the mutex and memory access can use relaxed ordering
-/// since we're not dealing with multiple threads. If it compares unequal,
+/// since we're not dealing with multiple threads. If it's not equal,
/// synchronization is left to the mutex, making relaxed memory ordering for
/// the `owner` field fine in all cases.
pub struct ReentrantMutex<T> {