Merge subtree update for toolchain nightly-2025-07-21

.github/workflows/flux.yml

@@ -9,7 +9,7 @@ on:
 
 env:
   FIXPOINT_VERSION: "556104ba5508891c357b0bdf819ce706e93d9349"
-  FLUX_VERSION: "f6bdf90c54ad6eed51b25c125f251cac01cfe170"
+  FLUX_VERSION: "ebafb8d0ca32d8c0fcd2a0cfef6b1b4bd4dc4a6f"
 
 jobs:
   check-flux-on-core:

library/alloc/src/boxed/thin.rs

@@ -5,7 +5,7 @@
 use core::error::Error;
 use core::fmt::{self, Debug, Display, Formatter};
 #[cfg(not(no_global_oom_handling))]
-use core::intrinsics::const_allocate;
+use core::intrinsics::{const_allocate, const_make_global};
 use core::marker::PhantomData;
 #[cfg(not(no_global_oom_handling))]
 use core::marker::Unsize;
@@ -340,9 +340,10 @@ impl<H> WithHeader<H> {
                     alloc.add(metadata_offset).cast();
                 // SAFETY: `*metadata_ptr` is within the allocation.
                 metadata_ptr.write(ptr::metadata::<Dyn>(ptr::dangling::<T>() as *const Dyn));
-
+                // SAFETY: valid heap allocation
+                const_make_global(alloc);
                 // SAFETY: we have just written the metadata.
-                &*(metadata_ptr)
+                &*metadata_ptr
             }
         };
 

library/alloc/src/fmt.rs

@@ -348,13 +348,13 @@
 //! format := '{' [ argument ] [ ':' format_spec ] [ ws ] * '}'
 //! argument := integer | identifier
 //!
-//! format_spec := [[fill]align][sign]['#']['0'][width]['.' precision]type
+//! format_spec := [[fill]align][sign]['#']['0'][width]['.' precision][type]
 //! fill := character
 //! align := '<' | '^' | '>'
 //! sign := '+' | '-'
 //! width := count
 //! precision := count | '*'
-//! type := '' | '?' | 'x?' | 'X?' | identifier
+//! type := '?' | 'x?' | 'X?' | identifier
 //! count := parameter | integer
 //! parameter := argument '$'
 //! ```

library/alloc/src/lib.rs

@@ -156,6 +156,7 @@
 #![feature(try_trait_v2)]
 #![feature(try_with_capacity)]
 #![feature(tuple_trait)]
+#![feature(ub_checks)]
 #![feature(unicode_internals)]
 #![feature(unsize)]
 #![feature(unwrap_infallible)]

library/alloc/src/string.rs

@@ -2611,7 +2611,7 @@ impl_eq! { Cow<'a, str>, &'b str }
 impl_eq! { Cow<'a, str>, String }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_default", issue = "67792")]
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
 impl const Default for String {
     /// Creates an empty `String`.
     #[inline]

library/alloc/src/vec/mod.rs

@@ -64,7 +64,7 @@ use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
 use core::ops::{self, Index, IndexMut, Range, RangeBounds};
 use core::ptr::{self, NonNull};
 use core::slice::{self, SliceIndex};
-use core::{fmt, intrinsics};
+use core::{fmt, intrinsics, ub_checks};
 
 #[stable(feature = "extract_if", since = "1.87.0")]
 pub use self::extract_if::ExtractIf;
@@ -1058,6 +1058,11 @@ impl<T, A: Allocator> Vec<T, A> {
     #[inline]
     #[unstable(feature = "allocator_api", issue = "32838")]
     pub unsafe fn from_raw_parts_in(ptr: *mut T, length: usize, capacity: usize, alloc: A) -> Self {
+        ub_checks::assert_unsafe_precondition!(
+            check_library_ub,
+            "Vec::from_raw_parts_in requires that length <= capacity",
+            (length: usize = length, capacity: usize = capacity) => length <= capacity
+        );
         unsafe { Vec { buf: RawVec::from_raw_parts_in(ptr, capacity, alloc), len: length } }
     }
 
@@ -1174,6 +1179,11 @@ impl<T, A: Allocator> Vec<T, A> {
     #[unstable(feature = "allocator_api", reason = "new API", issue = "32838")]
     // #[unstable(feature = "box_vec_non_null", issue = "130364")]
     pub unsafe fn from_parts_in(ptr: NonNull<T>, length: usize, capacity: usize, alloc: A) -> Self {
+        ub_checks::assert_unsafe_precondition!(
+            check_library_ub,
+            "Vec::from_parts_in requires that length <= capacity",
+            (length: usize = length, capacity: usize = capacity) => length <= capacity
+        );
         unsafe { Vec { buf: RawVec::from_nonnull_in(ptr, capacity, alloc), len: length } }
     }
 
@@ -1950,7 +1960,11 @@ impl<T, A: Allocator> Vec<T, A> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub unsafe fn set_len(&mut self, new_len: usize) {
-        debug_assert!(new_len <= self.capacity());
+        ub_checks::assert_unsafe_precondition!(
+            check_library_ub,
+            "Vec::set_len requires that new_len <= capacity()",
+            (new_len: usize = new_len, capacity: usize = self.capacity()) => new_len <= capacity
+        );
 
         self.len = new_len;
     }
@@ -3695,7 +3709,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// This is optimal if:
     ///
     /// * The tail (elements in the vector after `range`) is empty,
-    /// * or `replace_with` yields fewer or equal elements than `range`’s length
+    /// * or `replace_with` yields fewer or equal elements than `range`'s length
     /// * or the lower bound of its `size_hint()` is exact.
     ///
     /// Otherwise, a temporary vector is allocated and the tail is moved twice.
@@ -3895,7 +3909,7 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for Vec<T, A> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_default", issue = "67792")]
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
 impl<T> const Default for Vec<T> {
     /// Creates an empty `Vec<T>`.
     ///

library/core/src/any.rs

@@ -783,7 +783,7 @@ impl TypeId {
 
         // This is a provenance-stripping memcpy.
         for (i, chunk) in self.data.iter().copied().enumerate() {
-            let chunk = chunk.expose_provenance().to_ne_bytes();
+            let chunk = chunk.addr().to_ne_bytes();
             let start = i * chunk.len();
             bytes[start..(start + chunk.len())].copy_from_slice(&chunk);
         }

library/core/src/array/mod.rs

@@ -374,9 +374,10 @@ impl<'a, T, const N: usize> IntoIterator for &'a mut [T; N] {
 }
 
 #[stable(feature = "index_trait_on_arrays", since = "1.50.0")]
-impl<T, I, const N: usize> Index<I> for [T; N]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T, I, const N: usize> const Index<I> for [T; N]
 where
-    [T]: Index<I>,
+    [T]: ~const Index<I>,
 {
     type Output = <[T] as Index<I>>::Output;
 
@@ -387,9 +388,10 @@ where
 }
 
 #[stable(feature = "index_trait_on_arrays", since = "1.50.0")]
-impl<T, I, const N: usize> IndexMut<I> for [T; N]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T, I, const N: usize> const IndexMut<I> for [T; N]
 where
-    [T]: IndexMut<I>,
+    [T]: ~const IndexMut<I>,
 {
     #[inline]
     fn index_mut(&mut self, index: I) -> &mut Self::Output {

library/core/src/async_iter/async_iter.rs

@@ -28,15 +28,15 @@ pub trait AsyncIterator {
     /// async iterator state:
     ///
     /// - `Poll::Pending` means that this async iterator's next value is not ready
-    /// yet. Implementations will ensure that the current task will be notified
-    /// when the next value may be ready.
+    ///   yet. Implementations will ensure that the current task will be notified
+    ///   when the next value may be ready.
     ///
     /// - `Poll::Ready(Some(val))` means that the async iterator has successfully
-    /// produced a value, `val`, and may produce further values on subsequent
-    /// `poll_next` calls.
+    ///   produced a value, `val`, and may produce further values on subsequent
+    ///   `poll_next` calls.
     ///
     /// - `Poll::Ready(None)` means that the async iterator has terminated, and
-    /// `poll_next` should not be invoked again.
+    ///   `poll_next` should not be invoked again.
     ///
     /// # Panics
     ///

library/core/src/cell.rs

@@ -333,7 +333,7 @@ impl<T: Copy> Clone for Cell<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_default", issue = "67792")]
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
 impl<T: ~const Default> const Default for Cell<T> {
     /// Creates a `Cell<T>`, with the `Default` value for T.
     #[inline]
@@ -1324,7 +1324,7 @@ impl<T: Clone> Clone for RefCell<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_default", issue = "67792")]
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
 impl<T: ~const Default> const Default for RefCell<T> {
     /// Creates a `RefCell<T>`, with the `Default` value for T.
     #[inline]
@@ -2332,7 +2332,7 @@ impl<T: ?Sized> UnsafeCell<T> {
 }
 
 #[stable(feature = "unsafe_cell_default", since = "1.10.0")]
-#[rustc_const_unstable(feature = "const_default", issue = "67792")]
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
 impl<T: ~const Default> const Default for UnsafeCell<T> {
     /// Creates an `UnsafeCell`, with the `Default` value for T.
     fn default() -> UnsafeCell<T> {
@@ -2437,7 +2437,7 @@ impl<T: ?Sized> SyncUnsafeCell<T> {
 }
 
 #[unstable(feature = "sync_unsafe_cell", issue = "95439")]
-#[rustc_const_unstable(feature = "const_default", issue = "67792")]
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
 impl<T: ~const Default> const Default for SyncUnsafeCell<T> {
     /// Creates an `SyncUnsafeCell`, with the `Default` value for T.
     fn default() -> SyncUnsafeCell<T> {

library/core/src/cmp.rs

@@ -381,7 +381,8 @@ pub struct AssertParamIsEq<T: Eq + PointeeSized> {
 ///
 /// assert_eq!(2.cmp(&1), Ordering::Greater);
 /// ```
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+#[derive(Clone, Copy, Eq, PartialOrd, Ord, Debug, Hash)]
+#[derive_const(PartialEq)]
 #[stable(feature = "rust1", since = "1.0.0")]
 // This is a lang item only so that `BinOp::Cmp` in MIR can return it.
 // It has no special behavior, but does require that the three variants
@@ -1481,13 +1482,14 @@ pub trait PartialOrd<Rhs: PointeeSized = Self>: PartialEq<Rhs> + PointeeSized {
     }
 }
 
-fn default_chaining_impl<T: PointeeSized, U: PointeeSized>(
+fn default_chaining_impl<T, U>(
     lhs: &T,
     rhs: &U,
     p: impl FnOnce(Ordering) -> bool,
 ) -> ControlFlow<bool>
 where
-    T: PartialOrd<U>,
+    T: PartialOrd<U> + PointeeSized,
+    U: PointeeSized,
 {
     // It's important that this only call `partial_cmp` once, not call `eq` then
     // one of the relational operators.  We don't want to `bcmp`-then-`memcp` a

library/core/src/cmp/bytewise.rs

@@ -17,11 +17,15 @@ use crate::num::NonZero;
 /// - Neither `Self` nor `Rhs` have provenance, so integer comparisons are correct.
 /// - `<Self as PartialEq<Rhs>>::{eq,ne}` are equivalent to comparing the bytes.
 #[rustc_specialization_trait]
-pub(crate) unsafe trait BytewiseEq<Rhs = Self>: PartialEq<Rhs> + Sized {}
+#[const_trait]
+pub(crate) unsafe trait BytewiseEq<Rhs = Self>:
+    ~const PartialEq<Rhs> + Sized
+{
+}
 
 macro_rules! is_bytewise_comparable {
     ($($t:ty),+ $(,)?) => {$(
-        unsafe impl BytewiseEq for $t {}
+        unsafe impl const BytewiseEq for $t {}
     )+};
 }
 

library/core/src/default.rs

@@ -104,7 +104,7 @@ use crate::ascii::Char as AsciiChar;
 #[rustc_diagnostic_item = "Default"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[const_trait]
-#[rustc_const_unstable(feature = "const_default", issue = "67792")]
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
 pub trait Default: Sized {
     /// Returns the "default value" for a type.
     ///
@@ -151,7 +151,7 @@ pub macro Default($item:item) {
 macro_rules! default_impl {
     ($t:ty, $v:expr, $doc:tt) => {
         #[stable(feature = "rust1", since = "1.0.0")]
-        #[rustc_const_unstable(feature = "const_default", issue = "67792")]
+        #[rustc_const_unstable(feature = "const_default", issue = "143894")]
         impl const Default for $t {
             #[inline(always)]
             #[doc = $doc]

library/core/src/ffi/c_str.rs

@@ -142,16 +142,20 @@ pub enum FromBytesWithNulError {
 }
 
 #[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")]
-impl Error for FromBytesWithNulError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
+impl fmt::Display for FromBytesWithNulError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            Self::InteriorNul { .. } => "data provided contains an interior nul byte",
-            Self::NotNulTerminated => "data provided is not nul terminated",
+            Self::InteriorNul { position } => {
+                write!(f, "data provided contains an interior nul byte at byte position {position}")
+            }
+            Self::NotNulTerminated => write!(f, "data provided is not nul terminated"),
         }
     }
 }
 
+#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")]
+impl Error for FromBytesWithNulError {}
+
 /// An error indicating that no nul byte was present.
 ///
 /// A slice used to create a [`CStr`] must contain a nul byte somewhere
@@ -188,18 +192,6 @@ impl Default for &CStr {
     }
 }
 
-#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")]
-impl fmt::Display for FromBytesWithNulError {
-    #[allow(deprecated, deprecated_in_future)]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(self.description())?;
-        if let Self::InteriorNul { position } = self {
-            write!(f, " at byte pos {position}")?;
-        }
-        Ok(())
-    }
-}
-
 #[unstable(feature = "ub_checks", issue = "none")]
 impl Invariant for &CStr {
     /**

library/core/src/fmt/mod.rs

@@ -854,7 +854,6 @@ impl Display for Arguments<'_> {
 /// }";
 /// assert_eq!(format!("The origin is: {origin:#?}"), expected);
 /// ```
-
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(
     on(

library/core/src/fmt/num.rs

@@ -358,7 +358,7 @@ macro_rules! impl_Display {
                 }
                 #[cfg(feature = "optimize_for_size")]
                 {
-                    offset = _inner_slow_integer_to_str(self.unsigned_abs().$conv_fn(), &mut buf.buf);
+                    offset = ${concat(_inner_slow_integer_to_str, $gen_name)}(self.unsigned_abs().$conv_fn(), &mut buf.buf);
                 }
                 // Only difference between signed and unsigned are these 4 lines.
                 if self < 0 {
@@ -401,7 +401,7 @@ macro_rules! impl_Display {
                 }
                 #[cfg(feature = "optimize_for_size")]
                 {
-                    offset = _inner_slow_integer_to_str(self.$conv_fn(), &mut buf.buf);
+                    offset = ${concat(_inner_slow_integer_to_str, $gen_name)}(self.$conv_fn(), &mut buf.buf);
                 }
                 // SAFETY: Starting from `offset`, all elements of the slice have been set.
                 unsafe { slice_buffer_to_str(&buf.buf, offset) }
@@ -412,7 +412,7 @@ macro_rules! impl_Display {
         )*
 
         #[cfg(feature = "optimize_for_size")]
-        fn _inner_slow_integer_to_str(mut n: $u, buf: &mut [MaybeUninit::<u8>]) -> usize {
+        fn ${concat(_inner_slow_integer_to_str, $gen_name)}(mut n: $u, buf: &mut [MaybeUninit::<u8>]) -> usize {
             let mut curr = buf.len();
 
             // SAFETY: To show that it's OK to copy into `buf_ptr`, notice that at the beginning
@@ -437,7 +437,7 @@ macro_rules! impl_Display {
             const MAX_DEC_N: usize = $u::MAX.ilog(10) as usize + 1;
             let mut buf = [MaybeUninit::<u8>::uninit(); MAX_DEC_N];
 
-            let offset = _inner_slow_integer_to_str(n, &mut buf);
+            let offset = ${concat(_inner_slow_integer_to_str, $gen_name)}(n, &mut buf);
             // SAFETY: Starting from `offset`, all elements of the slice have been set.
             let buf_slice = unsafe { slice_buffer_to_str(&buf, offset) };
             f.pad_integral(is_nonnegative, "", buf_slice)