Merge pull request #498 from AltF02/rust-1.55

rust: port `liballoc` to release `1.55.0`

Author: ojeda

rust/alloc/borrow.rs

@@ -179,6 +179,7 @@ where
 /// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Cow")]
 pub enum Cow<'a, B: ?Sized + 'a>
 where
     B: ToOwned,

rust/alloc/boxed.rs

@@ -189,8 +189,6 @@ impl<T> Box<T> {
     /// ```
     #[cfg(not(no_global_oom_handling))]
     #[inline(always)]
-    #[doc(alias = "alloc")]
-    #[doc(alias = "malloc")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new(x: T) -> Self {
         box x
@@ -241,7 +239,6 @@ impl<T> Box<T> {
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
     #[inline]
-    #[doc(alias = "calloc")]
     #[unstable(feature = "new_uninit", issue = "63291")]
     pub fn new_zeroed() -> Box<mem::MaybeUninit<T>> {
         Self::new_zeroed_in(Global)

rust/alloc/collections/mod.rs

@@ -85,6 +85,7 @@ pub enum TryReserveError {
 
 #[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
 impl From<LayoutError> for TryReserveError {
+    /// Always evaluates to [`TryReserveError::CapacityOverflow`].
     #[inline]
     fn from(_: LayoutError) -> Self {
         TryReserveError::CapacityOverflow

rust/alloc/lib.rs

@@ -58,6 +58,10 @@
 //! [`Rc`]: rc
 //! [`RefCell`]: core::cell
 
+// To run liballoc tests without x.py without ending up with two copies of liballoc, Miri needs to be
+// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
+// rustc itself never sets the feature, so this line has no affect there.
+#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
 #![allow(unused_attributes)]
 #![stable(feature = "alloc", since = "1.36.0")]
 #![doc(
@@ -111,7 +115,6 @@
 #![feature(iter_zip)]
 #![feature(lang_items)]
 #![feature(layout_for_ptr)]
-#![feature(maybe_uninit_ref)]
 #![feature(negative_impls)]
 #![feature(never_type)]
 #![feature(nll)]
@@ -139,8 +142,7 @@
 #![feature(maybe_uninit_extra, maybe_uninit_slice, maybe_uninit_uninit_array)]
 #![feature(alloc_layout_extra)]
 #![feature(trusted_random_access)]
-#![cfg_attr(bootstrap, feature(try_trait))]
-#![cfg_attr(not(bootstrap), feature(try_trait_v2))]
+#![feature(try_trait_v2)]
 #![feature(min_type_alias_impl_trait)]
 #![feature(associated_type_bounds)]
 #![feature(slice_group_by)]

rust/alloc/macros.rs

@@ -37,8 +37,6 @@
 ///
 /// [`Vec`]: crate::vec::Vec
 #[cfg(not(test))]
-#[doc(alias = "alloc")]
-#[doc(alias = "malloc")]
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow_internal_unstable(box_syntax, liballoc_internals)]

rust/alloc/slice.rs

@@ -1133,7 +1133,7 @@ where
 }
 
 /// This merge sort borrows some (but not all) ideas from TimSort, which is described in detail
-/// [here](http://svn.python.org/projects/python/trunk/Objects/listsort.txt).
+/// [here](https://github.com/python/cpython/blob/main/Objects/listsort.txt).
 ///
 /// The algorithm identifies strictly descending and non-descending subsequences, which are called
 /// natural runs. There is a stack of pending runs yet to be merged. Each newly found run is pushed

rust/alloc/str.rs

@@ -399,7 +399,7 @@ impl str {
         return s;
 
         fn map_uppercase_sigma(from: &str, i: usize, to: &mut String) {
-            // See http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992
+            // See https://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992
             // for the definition of `Final_Sigma`.
             debug_assert!('Σ'.len_utf8() == 2);
             let is_word_final = case_ignoreable_then_cased(from[..i].chars().rev())

rust/alloc/string.rs

@@ -421,8 +421,6 @@ impl String {
     /// ```
     #[cfg(not(no_global_oom_handling))]
     #[inline]
-    #[doc(alias = "alloc")]
-    #[doc(alias = "malloc")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn with_capacity(capacity: usize) -> String {
         String { vec: Vec::with_capacity(capacity) }
@@ -1453,7 +1451,7 @@ impl String {
 
         unsafe {
             ptr::copy(self.vec.as_ptr().add(idx), self.vec.as_mut_ptr().add(idx + amt), len - idx);
-            ptr::copy(bytes.as_ptr(), self.vec.as_mut_ptr().add(idx), amt);
+            ptr::copy_nonoverlapping(bytes.as_ptr(), self.vec.as_mut_ptr().add(idx), amt);
             self.vec.set_len(len + amt);
         }
     }
@@ -1536,7 +1534,6 @@ impl String {
     /// assert_eq!(fancy_f.len(), 4);
     /// assert_eq!(fancy_f.chars().count(), 3);
     /// ```
-    #[doc(alias = "length")]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn len(&self) -> usize {
@@ -2771,33 +2768,31 @@ impl<'a> Drain<'a> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(string_drain_as_str)]
     /// let mut s = String::from("abc");
     /// let mut drain = s.drain(..);
     /// assert_eq!(drain.as_str(), "abc");
     /// let _ = drain.next().unwrap();
     /// assert_eq!(drain.as_str(), "bc");
     /// ```
-    #[unstable(feature = "string_drain_as_str", issue = "76905")] // Note: uncomment AsRef impls below when stabilizing.
+    #[stable(feature = "string_drain_as_str", since = "1.55.0")]
     pub fn as_str(&self) -> &str {
         self.iter.as_str()
     }
 }
 
-// Uncomment when stabilizing `string_drain_as_str`.
-// #[unstable(feature = "string_drain_as_str", issue = "76905")]
-// impl<'a> AsRef<str> for Drain<'a> {
-//     fn as_ref(&self) -> &str {
-//         self.as_str()
-//     }
-// }
-//
-// #[unstable(feature = "string_drain_as_str", issue = "76905")]
-// impl<'a> AsRef<[u8]> for Drain<'a> {
-//     fn as_ref(&self) -> &[u8] {
-//         self.as_str().as_bytes()
-//     }
-// }
+#[stable(feature = "string_drain_as_str", since = "1.55.0")]
+impl<'a> AsRef<str> for Drain<'a> {
+    fn as_ref(&self) -> &str {
+        self.as_str()
+    }
+}
+
+#[stable(feature = "string_drain_as_str", since = "1.55.0")]
+impl<'a> AsRef<[u8]> for Drain<'a> {
+    fn as_ref(&self) -> &[u8] {
+        self.as_str().as_bytes()
+    }
+}
 
 #[stable(feature = "drain", since = "1.6.0")]
 impl Iterator for Drain<'_> {

rust/alloc/sync.rs

@@ -496,6 +496,14 @@ impl<T> Arc<T> {
         unsafe { Pin::new_unchecked(Arc::new(data)) }
     }
 
+    /// Constructs a new `Pin<Arc<T>>`, return an error if allocation fails.
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[inline]
+    pub fn try_pin(data: T) -> Result<Pin<Arc<T>>, AllocError> {
+        unsafe { Ok(Pin::new_unchecked(Arc::try_new(data)?)) }
+    }
+
     /// Constructs a new `Arc<T>`, returning an error if allocation fails.
     ///
     /// # Examples
@@ -2333,6 +2341,20 @@ impl<T: ?Sized + Hash> Hash for Arc<T> {
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "from_for_ptrs", since = "1.6.0")]
 impl<T> From<T> for Arc<T> {
+    /// Converts a `T` into an `Arc<T>`
+    ///
+    /// The conversion moves the value into a
+    /// newly allocated `Arc`. It is equivalent to
+    /// calling `Arc::new(t)`.
+    ///
+    /// # Example
+    /// ```rust
+    /// # use std::sync::Arc;
+    /// let x = 5;
+    /// let arc = Arc::new(5);
+    ///
+    /// assert_eq!(Arc::from(x), arc);
+    /// ```
     fn from(t: T) -> Self {
         Arc::new(t)
     }

rust/alloc/vec/into_iter.rs

@@ -165,6 +165,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
         self.len()
     }
 
+    #[doc(hidden)]
     unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> Self::Item
     where
         Self: TrustedRandomAccess,

rust/alloc/vec/mod.rs

@@ -460,7 +460,6 @@ impl<T> Vec<T> {
     /// ```
     #[cfg(not(no_global_oom_handling))]
     #[inline]
-    #[doc(alias = "malloc")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn with_capacity(capacity: usize) -> Self {
         Self::with_capacity_in(capacity, Global)
@@ -890,7 +889,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// assert!(vec.capacity() >= 11);
     /// ```
     #[cfg(not(no_global_oom_handling))]
-    #[doc(alias = "realloc")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn reserve(&mut self, additional: usize) {
         self.buf.reserve(self.len, additional);
@@ -917,7 +915,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// assert!(vec.capacity() >= 11);
     /// ```
     #[cfg(not(no_global_oom_handling))]
-    #[doc(alias = "realloc")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn reserve_exact(&mut self, additional: usize) {
         self.buf.reserve_exact(self.len, additional);
@@ -955,7 +952,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// }
     /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
     /// ```
-    #[doc(alias = "realloc")]
     #[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
     pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
         self.buf.try_reserve(self.len, additional)
@@ -997,7 +993,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// }
     /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
     /// ```
-    #[doc(alias = "realloc")]
     #[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
     pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
         self.buf.try_reserve_exact(self.len, additional)
@@ -1018,7 +1013,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// assert!(vec.capacity() >= 3);
     /// ```
     #[cfg(not(no_global_oom_handling))]
-    #[doc(alias = "realloc")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn shrink_to_fit(&mut self) {
         // The capacity is never less than the length, and there's nothing to do when
@@ -1076,7 +1070,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// assert!(vec.capacity() >= 3);
     /// ```
     #[cfg(not(no_global_oom_handling))]
-    #[doc(alias = "realloc")]
     #[unstable(feature = "shrink_to", reason = "new API", issue = "56431")]
     pub fn shrink_to(&mut self, min_capacity: usize) {
         if self.capacity() > min_capacity {
@@ -2007,7 +2000,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// let a = vec![1, 2, 3];
     /// assert_eq!(a.len(), 3);
     /// ```
-    #[doc(alias = "length")]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn len(&self) -> usize {
@@ -2686,6 +2678,18 @@ impl<T: Clone, A: Allocator + Clone> Clone for Vec<T, A> {
     }
 }
 
+/// The hash of a vector is the same as that of the corresponding slice,
+/// as required by the `core::borrow::Borrow` implementation.
+///
+/// ```
+/// #![feature(build_hasher_simple_hash_one)]
+/// use std::hash::BuildHasher;
+///
+/// let b = std::collections::hash_map::RandomState::new();
+/// let v: Vec<u8> = vec![0xa8, 0x3c, 0x09];
+/// let s: &[u8] = &[0xa8, 0x3c, 0x09];
+/// assert_eq!(b.hash_one(v), b.hash_one(s));
+/// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Hash, A: Allocator> Hash for Vec<T, A> {
     #[inline]
@@ -2830,6 +2834,8 @@ impl<T, A: Allocator> Vec<T, A> {
             }
             unsafe {
                 ptr::write(self.as_mut_ptr().add(len), element);
+                // Since next() executes user code which can panic we have to bump the length
+                // after each step.
                 // NB can't overflow since we would have had to alloc the address space
                 self.set_len(len + 1);
             }

rust/alloc/vec/spec_extend.rs

@@ -60,6 +60,8 @@ where
                 iterator.for_each(move |element| {
                     ptr::write(ptr, element);
                     ptr = ptr.offset(1);
+                    // Since the loop executes user code which can panic we have to bump the pointer
+                    // after each step.
                     // NB can't overflow since we would have had to alloc the address space
                     local_len.increment_len(1);
                 });