tautschnig
diff --git a/‎Cargo.lock
+14-15 b/‎Cargo.lock
+14-15
diff --git a/‎alloc/Cargo.toml
+1-1 b/‎alloc/Cargo.toml
+1-1
diff --git a/‎alloc/src/alloc.rs
+8-5 b/‎alloc/src/alloc.rs
+8-5
diff --git a/‎alloc/src/boxed.rs
+10-1 b/‎alloc/src/boxed.rs
+10-1
diff --git a/‎alloc/src/boxed/convert.rs
+45 b/‎alloc/src/boxed/convert.rs
+45
diff --git a/‎alloc/src/collections/btree/map.rs
+48-38 b/‎alloc/src/collections/btree/map.rs
+48-38
@@ -10,7 +10,7 @@ edition = "2021"
 
 [dependencies]
 core = { path = "../core" }
-compiler_builtins = { version = "0.1.136", features = ['rustc-dep-of-std'] }
+compiler_builtins = { version = "=0.1.138", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
 rand = { version = "0.8.5", default-features = false, features = ["alloc"] }
 
@@ -61,7 +61,7 @@ pub use std::alloc::Global;
 /// of the allocator registered with the `#[global_allocator]` attribute
 /// if there is one, or the `std` crate’s default.
 ///
-/// This function is expected to be deprecated in favor of the `alloc` method
+/// This function is expected to be deprecated in favor of the `allocate` method
 /// of the [`Global`] type when it and the [`Allocator`] trait become stable.
 ///
 /// # Safety
@@ -106,7 +106,7 @@ pub unsafe fn alloc(layout: Layout) -> *mut u8 {
 /// of the allocator registered with the `#[global_allocator]` attribute
 /// if there is one, or the `std` crate’s default.
 ///
-/// This function is expected to be deprecated in favor of the `dealloc` method
+/// This function is expected to be deprecated in favor of the `deallocate` method
 /// of the [`Global`] type when it and the [`Allocator`] trait become stable.
 ///
 /// # Safety
@@ -125,7 +125,7 @@ pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
 /// of the allocator registered with the `#[global_allocator]` attribute
 /// if there is one, or the `std` crate’s default.
 ///
-/// This function is expected to be deprecated in favor of the `realloc` method
+/// This function is expected to be deprecated in favor of the `grow` and `shrink` methods
 /// of the [`Global`] type when it and the [`Allocator`] trait become stable.
 ///
 /// # Safety
@@ -145,7 +145,7 @@ pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8
 /// of the allocator registered with the `#[global_allocator]` attribute
 /// if there is one, or the `std` crate’s default.
 ///
-/// This function is expected to be deprecated in favor of the `alloc_zeroed` method
+/// This function is expected to be deprecated in favor of the `allocate_zeroed` method
 /// of the [`Global`] type when it and the [`Allocator`] trait become stable.
 ///
 /// # Safety
@@ -155,11 +155,14 @@ pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8
 /// # Examples
 ///
 /// ```
-/// use std::alloc::{alloc_zeroed, dealloc, Layout};
+/// use std::alloc::{alloc_zeroed, dealloc, handle_alloc_error, Layout};
 ///
 /// unsafe {
 ///     let layout = Layout::new::<u16>();
 ///     let ptr = alloc_zeroed(layout);
+///     if ptr.is_null() {
+///         handle_alloc_error(layout);
+///     }
 ///
 ///     assert_eq!(*(ptr as *mut u16), 0);
 ///
 
@@ -191,6 +191,8 @@ use core::error::{self, Error};
 use core::fmt;
 use core::future::Future;
 use core::hash::{Hash, Hasher};
+#[cfg(not(bootstrap))]
+use core::marker::PointerLike;
 use core::marker::{Tuple, Unsize};
 use core::mem::{self, SizedTypeProperties};
 use core::ops::{
@@ -225,6 +227,7 @@ pub use thin::ThinBox;
 #[fundamental]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_insignificant_dtor]
+#[cfg_attr(not(bootstrap), doc(search_unbox))]
 // The declaration of the `Box` struct must be kept in sync with the
 // compiler or ICEs will happen.
 pub struct Box<
@@ -1499,6 +1502,7 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     /// [`as_ptr`]: Self::as_ptr
     #[unstable(feature = "box_as_ptr", issue = "129090")]
     #[rustc_never_returns_null_ptr]
+    #[cfg_attr(not(bootstrap), rustc_as_ptr)]
     #[inline]
     pub fn as_mut_ptr(b: &mut Self) -> *mut T {
         // This is a primitive deref, not going through `DerefMut`, and therefore not materializing
@@ -1547,6 +1551,7 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     /// [`as_ptr`]: Self::as_ptr
     #[unstable(feature = "box_as_ptr", issue = "129090")]
     #[rustc_never_returns_null_ptr]
+    #[cfg_attr(not(bootstrap), rustc_as_ptr)]
     #[inline]
     pub fn as_ptr(b: &Self) -> *const T {
         // This is a primitive deref, not going through `DerefMut`, and therefore not materializing
@@ -1734,7 +1739,7 @@ impl<T: Clone, A: Allocator + Clone> Clone for Box<T, A> {
         // Pre-allocate memory to allow writing the cloned value directly.
         let mut boxed = Self::new_uninit_in(self.1.clone());
         unsafe {
-            (**self).clone_to_uninit(boxed.as_mut_ptr());
+            (**self).clone_to_uninit(boxed.as_mut_ptr().cast());
             boxed.assume_init()
         }
     }
@@ -2128,3 +2133,7 @@ impl<E: Error> Error for Box<E> {
         Error::provide(&**self, request);
     }
 }
+
+#[cfg(not(bootstrap))]
+#[unstable(feature = "pointer_like_trait", issue = "none")]
+impl<T> PointerLike for Box<T> {}
@@ -109,6 +109,29 @@ impl<T: Clone> From<&[T]> for Box<[T]> {
     }
 }
 
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_mut_slice", since = "CURRENT_RUSTC_VERSION")]
+impl<T: Clone> From<&mut [T]> for Box<[T]> {
+    /// Converts a `&mut [T]` into a `Box<[T]>`
+    ///
+    /// This conversion allocates on the heap
+    /// and performs a copy of `slice` and its contents.
+    ///
+    /// # Examples
+    /// ```rust
+    /// // create a &mut [u8] which will be used to create a Box<[u8]>
+    /// let mut array = [104, 101, 108, 108, 111];
+    /// let slice: &mut [u8] = &mut array;
+    /// let boxed_slice: Box<[u8]> = Box::from(slice);
+    ///
+    /// println!("{boxed_slice:?}");
+    /// ```
+    #[inline]
+    fn from(slice: &mut [T]) -> Box<[T]> {
+        Self::from(&*slice)
+    }
+}
+
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "box_from_cow", since = "1.45.0")]
 impl<T: Clone> From<Cow<'_, [T]>> for Box<[T]> {
@@ -147,6 +170,28 @@ impl From<&str> for Box<str> {
     }
 }
 
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_mut_slice", since = "CURRENT_RUSTC_VERSION")]
+impl From<&mut str> for Box<str> {
+    /// Converts a `&mut str` into a `Box<str>`
+    ///
+    /// This conversion allocates on the heap
+    /// and performs a copy of `s`.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// let mut original = String::from("hello");
+    /// let original: &mut str = &mut original;
+    /// let boxed: Box<str> = Box::from(original);
+    /// println!("{boxed}");
+    /// ```
+    #[inline]
+    fn from(s: &mut str) -> Box<str> {
+        Self::from(&*s)
+    }
+}
+
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "box_from_cow", since = "1.45.0")]
 impl From<Cow<'_, str>> for Box<str> {
 
@@ -289,40 +289,12 @@ impl<K: Clone, V: Clone, A: Allocator + Clone> Clone for BTreeMap<K, V, A> {
     }
 }
 
-impl<K, Q: ?Sized, A: Allocator + Clone> super::Recover<Q> for BTreeMap<K, SetValZST, A>
-where
-    K: Borrow<Q> + Ord,
-    Q: Ord,
-{
-    type Key = K;
-
-    fn get(&self, key: &Q) -> Option<&K> {
-        let root_node = self.root.as_ref()?.reborrow();
-        match root_node.search_tree(key) {
-            Found(handle) => Some(handle.into_kv().0),
-            GoDown(_) => None,
-        }
-    }
-
-    fn take(&mut self, key: &Q) -> Option<K> {
-        let (map, dormant_map) = DormantMutRef::new(self);
-        let root_node = map.root.as_mut()?.borrow_mut();
-        match root_node.search_tree(key) {
-            Found(handle) => Some(
-                OccupiedEntry {
-                    handle,
-                    dormant_map,
-                    alloc: (*map.alloc).clone(),
-                    _marker: PhantomData,
-                }
-                .remove_kv()
-                .0,
-            ),
-            GoDown(_) => None,
-        }
-    }
-
-    fn replace(&mut self, key: K) -> Option<K> {
+/// Internal functionality for `BTreeSet`.
+impl<K, A: Allocator + Clone> BTreeMap<K, SetValZST, A> {
+    pub(super) fn replace(&mut self, key: K) -> Option<K>
+    where
+        K: Ord,
+    {
         let (map, dormant_map) = DormantMutRef::new(self);
         let root_node =
             map.root.get_or_insert_with(|| Root::new((*map.alloc).clone())).borrow_mut();
@@ -705,20 +677,58 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
         }
     }
 
-    /// Returns the key-value pair corresponding to the supplied key.
+    /// Returns the key-value pair corresponding to the supplied key. This is
+    /// potentially useful:
+    /// - for key types where non-identical keys can be considered equal;
+    /// - for getting the `&K` stored key value from a borrowed `&Q` lookup key; or
+    /// - for getting a reference to a key with the same lifetime as the collection.
     ///
     /// The supplied key may be any borrowed form of the map's key type, but the ordering
     /// on the borrowed form *must* match the ordering on the key type.
     ///
     /// # Examples
     ///
     /// ```
+    /// use std::cmp::Ordering;
     /// use std::collections::BTreeMap;
     ///
+    /// #[derive(Clone, Copy, Debug)]
+    /// struct S {
+    ///     id: u32,
+    /// #   #[allow(unused)] // prevents a "field `name` is never read" error
+    ///     name: &'static str, // ignored by equality and ordering operations
+    /// }
+    ///
+    /// impl PartialEq for S {
+    ///     fn eq(&self, other: &S) -> bool {
+    ///         self.id == other.id
+    ///     }
+    /// }
+    ///
+    /// impl Eq for S {}
+    ///
+    /// impl PartialOrd for S {
+    ///     fn partial_cmp(&self, other: &S) -> Option<Ordering> {
+    ///         self.id.partial_cmp(&other.id)
+    ///     }
+    /// }
+    ///
+    /// impl Ord for S {
+    ///     fn cmp(&self, other: &S) -> Ordering {
+    ///         self.id.cmp(&other.id)
+    ///     }
+    /// }
+    ///
+    /// let j_a = S { id: 1, name: "Jessica" };
+    /// let j_b = S { id: 1, name: "Jess" };
+    /// let p = S { id: 2, name: "Paul" };
+    /// assert_eq!(j_a, j_b);
+    ///
     /// let mut map = BTreeMap::new();
-    /// map.insert(1, "a");
-    /// assert_eq!(map.get_key_value(&1), Some((&1, &"a")));
-    /// assert_eq!(map.get_key_value(&2), None);
+    /// map.insert(j_a, "Paris");
+    /// assert_eq!(map.get_key_value(&j_a), Some((&j_a, &"Paris")));
+    /// assert_eq!(map.get_key_value(&j_b), Some((&j_a, &"Paris"))); // the notable case
+    /// assert_eq!(map.get_key_value(&p), None);
     /// ```
     #[stable(feature = "map_get_key_value", since = "1.40.0")]
     pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)>