Merge from rustc

Author: The Miri Cronjob Bot

Cargo.lock

@@ -8,7 +8,7 @@ repository = "https://github.com/rust-lang/rust.git"
 description = "The Rust core allocation and collections library"
 autotests = false
 autobenches = false
-edition = "2021"
+edition = "2024"
 
 [lib]
 test = false

alloc/Cargo.toml

@@ -239,7 +239,7 @@ pub struct Box<
 /// This is the surface syntax for `box <expr>` expressions.
 #[rustc_intrinsic]
 #[unstable(feature = "liballoc_internals", issue = "none")]
-pub fn box_new<T>(_x: T) -> Box<T>;
+pub fn box_new<T>(x: T) -> Box<T>;
 
 impl<T> Box<T> {
     /// Allocates memory on the heap and then places `x` into it.

alloc/src/boxed.rs

@@ -361,6 +361,74 @@ impl<T: Ord, A: Allocator> DerefMut for PeekMut<'_, T, A> {
 }
 
 impl<'a, T: Ord, A: Allocator> PeekMut<'a, T, A> {
+    /// Sifts the current element to its new position.
+    ///
+    /// Afterwards refers to the new element. Returns if the element changed.
+    ///
+    /// ## Examples
+    ///
+    /// The condition can be used to upper bound all elements in the heap. When only few elements
+    /// are affected, the heap's sort ensures this is faster than a reconstruction from the raw
+    /// element list and requires no additional allocation.
+    ///
+    /// ```
+    /// #![feature(binary_heap_peek_mut_refresh)]
+    /// use std::collections::BinaryHeap;
+    ///
+    /// let mut heap: BinaryHeap<u32> = (0..128).collect();
+    /// let mut peek = heap.peek_mut().unwrap();
+    ///
+    /// loop {
+    ///     *peek = 99;
+    ///
+    ///     if !peek.refresh() {
+    ///         break;
+    ///     }
+    /// }
+    ///
+    /// // Post condition, this is now an upper bound.
+    /// assert!(*peek < 100);
+    /// ```
+    ///
+    /// When the element remains the maximum after modification, the peek remains unchanged:
+    ///
+    /// ```
+    /// #![feature(binary_heap_peek_mut_refresh)]
+    /// use std::collections::BinaryHeap;
+    ///
+    /// let mut heap: BinaryHeap<u32> = [1, 2, 3].into();
+    /// let mut peek = heap.peek_mut().unwrap();
+    ///
+    /// assert_eq!(*peek, 3);
+    /// *peek = 42;
+    ///
+    /// // When we refresh, the peek is updated to the new maximum.
+    /// assert!(!peek.refresh(), "42 is even larger than 3");
+    /// assert_eq!(*peek, 42);
+    /// ```
+    #[unstable(feature = "binary_heap_peek_mut_refresh", issue = "138355")]
+    #[must_use = "is equivalent to dropping and getting a new PeekMut except for return information"]
+    pub fn refresh(&mut self) -> bool {
+        // The length of the underlying heap is unchanged by sifting down. The value stored for leak
+        // amplification thus remains accurate. We erase the leak amplification firstly because the
+        // operation is then equivalent to constructing a new PeekMut and secondly this avoids any
+        // future complication where original_len being non-empty would be interpreted as the heap
+        // having been leak amplified instead of checking the heap itself.
+        if let Some(original_len) = self.original_len.take() {
+            // SAFETY: This is how many elements were in the Vec at the time of
+            // the BinaryHeap::peek_mut call.
+            unsafe { self.heap.data.set_len(original_len.get()) };
+
+            // The length of the heap did not change by sifting, upholding our own invariants.
+
+            // SAFETY: PeekMut is only instantiated for non-empty heaps.
+            (unsafe { self.heap.sift_down(0) }) != 0
+        } else {
+            // The element was not modified.
+            false
+        }
+    }
+
     /// Removes the peeked value from the heap and returns it.
     #[stable(feature = "binary_heap_peek_mut_pop", since = "1.18.0")]
     pub fn pop(mut this: PeekMut<'a, T, A>) -> T {
@@ -672,6 +740,8 @@ impl<T: Ord, A: Allocator> BinaryHeap<T, A> {
     /// # Safety
     ///
     /// The caller must guarantee that `pos < self.len()`.
+    ///
+    /// Returns the new position of the element.
     unsafe fn sift_up(&mut self, start: usize, pos: usize) -> usize {
         // Take out the value at `pos` and create a hole.
         // SAFETY: The caller guarantees that pos < self.len()
@@ -698,10 +768,12 @@ impl<T: Ord, A: Allocator> BinaryHeap<T, A> {
     /// Take an element at `pos` and move it down the heap,
     /// while its children are larger.
     ///
+    /// Returns the new position of the element.
+    ///
     /// # Safety
     ///
     /// The caller must guarantee that `pos < end <= self.len()`.
-    unsafe fn sift_down_range(&mut self, pos: usize, end: usize) {
+    unsafe fn sift_down_range(&mut self, pos: usize, end: usize) -> usize {
         // SAFETY: The caller guarantees that pos < end <= self.len().
         let mut hole = unsafe { Hole::new(&mut self.data, pos) };
         let mut child = 2 * hole.pos() + 1;
@@ -721,7 +793,7 @@ impl<T: Ord, A: Allocator> BinaryHeap<T, A> {
             // SAFETY: child is now either the old child or the old child+1
             //  We already proven that both are < self.len() and != hole.pos()
             if hole.element() >= unsafe { hole.get(child) } {
-                return;
+                return hole.pos();
             }
 
             // SAFETY: same as above.
@@ -736,16 +808,18 @@ impl<T: Ord, A: Allocator> BinaryHeap<T, A> {
             //  child == 2 * hole.pos() + 1 != hole.pos().
             unsafe { hole.move_to(child) };
         }
+
+        hole.pos()
     }
 
     /// # Safety
     ///
     /// The caller must guarantee that `pos < self.len()`.
-    unsafe fn sift_down(&mut self, pos: usize) {
+    unsafe fn sift_down(&mut self, pos: usize) -> usize {
         let len = self.len();
         // SAFETY: pos < len is guaranteed by the caller and
         //  obviously len = self.len() <= self.len().
-        unsafe { self.sift_down_range(pos, len) };
+        unsafe { self.sift_down_range(pos, len) }
     }
 
     /// Take an element at `pos` and move it all the way down the heap,

alloc/src/collections/binary_heap/mod.rs

@@ -9,7 +9,7 @@ autobenches = false
 # If you update this, be sure to update it in a bunch of other places too!
 # As of 2024, it was src/tools/opt-dist, the core-no-fp-fmt-parse test and
 # the version of the prelude imported in core/lib.rs.
-edition = "2021"
+edition = "2024"
 
 [lib]
 test = false

core/Cargo.toml

@@ -133,7 +133,10 @@ mod c_char_definition {
 
 mod c_long_definition {
     cfg_if! {
-        if #[cfg(all(target_pointer_width = "64", not(windows)))] {
+        if #[cfg(any(
+            all(target_pointer_width = "64", not(windows)),
+            // wasm32 Linux ABI uses 64-bit long
+            all(target_arch = "wasm32", target_os = "linux")))] {
             pub(super) type c_long = i64;
             pub(super) type c_ulong = u64;
         } else {

core/src/ffi/primitives.rs

@@ -306,15 +306,15 @@ impl<'f> Drop for VaListImpl<'f> {
 /// `va_copy`.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-unsafe fn va_end(_ap: &mut VaListImpl<'_>);
+unsafe fn va_end(ap: &mut VaListImpl<'_>);
 
 /// Copies the current location of arglist `src` to the arglist `dst`.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-unsafe fn va_copy<'f>(_dest: *mut VaListImpl<'f>, _src: &VaListImpl<'f>);
+unsafe fn va_copy<'f>(dest: *mut VaListImpl<'f>, src: &VaListImpl<'f>);
 
 /// Loads an argument of type `T` from the `va_list` `ap` and increment the
 /// argument `ap` points to.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-unsafe fn va_arg<T: sealed_trait::VaArgSafe>(_ap: &mut VaListImpl<'_>) -> T;
+unsafe fn va_arg<T: sealed_trait::VaArgSafe>(ap: &mut VaListImpl<'_>) -> T;

core/src/ffi/va_list.rs

@@ -29,7 +29,7 @@ fn float_to_decimal_common_exact<T>(
     fmt: &mut Formatter<'_>,
     num: &T,
     sign: flt2dec::Sign,
-    precision: usize,
+    precision: u16,
 ) -> Result
 where
     T: flt2dec::DecodableFloat,
@@ -40,7 +40,7 @@ where
         flt2dec::strategy::grisu::format_exact,
         *num,
         sign,
-        precision,
+        precision.into(),
         &mut buf,
         &mut parts,
     );
@@ -55,7 +55,7 @@ fn float_to_decimal_common_shortest<T>(
     fmt: &mut Formatter<'_>,
     num: &T,
     sign: flt2dec::Sign,
-    precision: usize,
+    precision: u16,
 ) -> Result
 where
     T: flt2dec::DecodableFloat,
@@ -68,7 +68,7 @@ where
         flt2dec::strategy::grisu::format_shortest,
         *num,
         sign,
-        precision,
+        precision.into(),
         &mut buf,
         &mut parts,
     );
@@ -101,7 +101,7 @@ fn float_to_exponential_common_exact<T>(
     fmt: &mut Formatter<'_>,
     num: &T,
     sign: flt2dec::Sign,
-    precision: usize,
+    precision: u16,
     upper: bool,
 ) -> Result
 where
@@ -113,7 +113,7 @@ where
         flt2dec::strategy::grisu::format_exact,
         *num,
         sign,
-        precision,
+        precision.into(),
         upper,
         &mut buf,
         &mut parts,