Merge pull request torvalds#799 from ojeda/rust-1.62.0

Rust 1.62.0

.github/workflows/ci.yaml

@@ -7,7 +7,7 @@ on:
 jobs:
   ci:
     runs-on: ubuntu-20.04
-    container: ghcr.io/rust-for-linux/ci:Rust-1.61.0
+    container: ghcr.io/rust-for-linux/ci:Rust-1.62.0
     timeout-minutes: 20
 
     strategy:

Documentation/process/changes.rst

@@ -31,7 +31,7 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
 GNU C                  5.1              gcc --version
 Clang/LLVM (optional)  11.0.0           clang --version
-Rust (optional)        1.61.0           rustc --version
+Rust (optional)        1.62.0           rustc --version
 bindgen (optional)     0.56.0           bindgen --version
 GNU make               3.81             make --version
 binutils               2.23             ld -v

rust/alloc/alloc.rs

@@ -328,16 +328,12 @@ unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
 #[cfg_attr(not(test), lang = "box_free")]
 #[inline]
 #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-#[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
 // This signature has to be the same as `Box`, otherwise an ICE will happen.
 // When an additional parameter to `Box` is added (like `A: Allocator`), this has to be added here as
 // well.
 // For example if `Box` is changed to  `struct Box<T: ?Sized, A: Allocator>(Unique<T>, A)`,
 // this function has to be changed to `fn box_free<T: ?Sized, A: Allocator>(Unique<T>, A)` as well.
-pub(crate) const unsafe fn box_free<
-    T: ?Sized,
-    A: ~const Allocator + ~const Drop + ~const Destruct,
->(
+pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Destruct>(
     ptr: Unique<T>,
     alloc: A,
 ) {
@@ -393,7 +389,7 @@ pub const fn handle_alloc_error(layout: Layout) -> ! {
 #[cfg(all(not(no_global_oom_handling), test))]
 pub use std::alloc::handle_alloc_error;
 
-#[cfg(all(not(no_global_oom_handling), not(any(target_os = "hermit", test))))]
+#[cfg(all(not(no_global_oom_handling), not(test)))]
 #[doc(hidden)]
 #[allow(unused_attributes)]
 #[unstable(feature = "alloc_internals", issue = "none")]

rust/alloc/borrow.rs

@@ -294,8 +294,7 @@ impl<B: ?Sized + ToOwned> Cow<'_, B> {
     ///
     /// # Examples
     ///
-    /// Calling `into_owned` on a `Cow::Borrowed` clones the underlying data
-    /// and becomes a `Cow::Owned`:
+    /// Calling `into_owned` on a `Cow::Borrowed` returns a clone of the borrowed data:
     ///
     /// ```
     /// use std::borrow::Cow;
@@ -309,7 +308,8 @@ impl<B: ?Sized + ToOwned> Cow<'_, B> {
     /// );
     /// ```
     ///
-    /// Calling `into_owned` on a `Cow::Owned` is a no-op:
+    /// Calling `into_owned` on a `Cow::Owned` returns the owned data. The data is moved out of the
+    /// `Cow` without being cloned.
     ///
     /// ```
     /// use std::borrow::Cow;
@@ -333,7 +333,6 @@ impl<B: ?Sized + ToOwned> Cow<'_, B> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_deref", issue = "88955")]
-#[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
 impl<B: ?Sized + ToOwned> const Deref for Cow<'_, B>
 where
     B::Owned: ~const Borrow<B>,

rust/alloc/boxed.rs

@@ -165,6 +165,11 @@ use crate::str::from_boxed_utf8_unchecked;
 #[cfg(not(no_global_oom_handling))]
 use crate::vec::Vec;
 
+#[unstable(feature = "thin_box", issue = "92791")]
+pub use thin::ThinBox;
+
+mod thin;
+
 /// A pointer type for heap allocation.
 ///
 /// See the [module-level documentation](../../std/boxed/index.html) for more.
@@ -351,10 +356,9 @@ impl<T, A: Allocator> Box<T, A> {
     #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[must_use]
     #[inline]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn new_in(x: T, alloc: A) -> Self
     where
-        A: ~const Allocator + ~const Drop + ~const Destruct,
+        A: ~const Allocator + ~const Destruct,
     {
         let mut boxed = Self::new_uninit_in(alloc);
         unsafe {
@@ -381,11 +385,10 @@ impl<T, A: Allocator> Box<T, A> {
     #[unstable(feature = "allocator_api", issue = "32838")]
     #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>
     where
-        T: ~const Drop + ~const Destruct,
-        A: ~const Allocator + ~const Drop + ~const Destruct,
+        T: ~const Destruct,
+        A: ~const Allocator + ~const Destruct,
     {
         let mut boxed = Self::try_new_uninit_in(alloc)?;
         unsafe {
@@ -419,10 +422,9 @@ impl<T, A: Allocator> Box<T, A> {
     #[cfg(not(no_global_oom_handling))]
     #[must_use]
     // #[unstable(feature = "new_uninit", issue = "63291")]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
     where
-        A: ~const Allocator + ~const Drop + ~const Destruct,
+        A: ~const Allocator + ~const Destruct,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
@@ -458,10 +460,9 @@ impl<T, A: Allocator> Box<T, A> {
     #[unstable(feature = "allocator_api", issue = "32838")]
     // #[unstable(feature = "new_uninit", issue = "63291")]
     #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
     where
-        A: ~const Allocator + ~const Drop + ~const Destruct,
+        A: ~const Allocator + ~const Destruct,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         let ptr = alloc.allocate(layout)?.cast();
@@ -493,10 +494,9 @@ impl<T, A: Allocator> Box<T, A> {
     #[cfg(not(no_global_oom_handling))]
     // #[unstable(feature = "new_uninit", issue = "63291")]
     #[must_use]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
     where
-        A: ~const Allocator + ~const Drop + ~const Destruct,
+        A: ~const Allocator + ~const Destruct,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
@@ -532,10 +532,9 @@ impl<T, A: Allocator> Box<T, A> {
     #[unstable(feature = "allocator_api", issue = "32838")]
     // #[unstable(feature = "new_uninit", issue = "63291")]
     #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
     where
-        A: ~const Allocator + ~const Drop + ~const Destruct,
+        A: ~const Allocator + ~const Destruct,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         let ptr = alloc.allocate_zeroed(layout)?.cast();
@@ -549,10 +548,9 @@ impl<T, A: Allocator> Box<T, A> {
     #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[must_use]
     #[inline(always)]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn pin_in(x: T, alloc: A) -> Pin<Self>
     where
-        A: 'static + ~const Allocator + ~const Drop + ~const Destruct,
+        A: 'static + ~const Allocator + ~const Destruct,
     {
         Self::into_pin(Self::new_in(x, alloc))
     }
@@ -581,10 +579,9 @@ impl<T, A: Allocator> Box<T, A> {
     #[unstable(feature = "box_into_inner", issue = "80437")]
     #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    #[cfg_attr(not(bootstrap), allow(drop_bounds))] // FIXME remove `~const Drop` and this attr when bumping
     pub const fn into_inner(boxed: Self) -> T
     where
-        Self: ~const Drop + ~const Destruct,
+        Self: ~const Destruct,
     {
         *boxed
     }
@@ -1197,17 +1194,25 @@ impl<T: Default> Default for Box<T> {
 
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> Default for Box<[T]> {
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl<T> const Default for Box<[T]> {
     fn default() -> Self {
-        Box::<[T; 0]>::new([])
+        let ptr: Unique<[T]> = Unique::<[T; 0]>::dangling();
+        Box(ptr, Global)
     }
 }
 
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "default_box_extra", since = "1.17.0")]
-impl Default for Box<str> {
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl const Default for Box<str> {
     fn default() -> Self {
-        unsafe { from_boxed_utf8_unchecked(Default::default()) }
+        // SAFETY: This is the same as `Unique::cast<U>` but with an unsized `U = str`.
+        let ptr: Unique<str> = unsafe {
+            let bytes: Unique<[u8]> = Unique::<[u8; 0]>::dangling();
+            Unique::new_unchecked(bytes.as_ptr() as *mut str)
+        };
+        Box(ptr, Global)
     }
 }
 
@@ -1366,6 +1371,12 @@ impl<T: ?Sized + Hasher, A: Allocator> Hasher for Box<T, A> {
     fn write_isize(&mut self, i: isize) {
         (**self).write_isize(i)
     }
+    fn write_length_prefix(&mut self, len: usize) {
+        (**self).write_length_prefix(len)
+    }
+    fn write_str(&mut self, s: &str) {
+        (**self).write_str(s)
+    }
 }
 
 #[cfg(not(no_global_oom_handling))]