Auto merge of rust-lang#133026 - workingjubilee:rollup-q8ig6ah, r=workingjubilee

Rollup of 7 pull requests

Successful merges:

 - rust-lang#131304 (float types: move copysign, abs, signum to libcore)
 - rust-lang#132907 (Change intrinsic declarations to new style)
 - rust-lang#132971 (Handle infer vars in anon consts on stable)
 - rust-lang#133003 (Make `CloneToUninit` dyn-compatible)
 - rust-lang#133004 (btree: simplify the backdoor between set and map)
 - rust-lang#133008 (update outdated comment about test-float-parse)
 - rust-lang#133012 (Add test cases for rust-lang#125918)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

Diff for: alloc/src/boxed.rs

@@ -1735,7 +1735,7 @@ 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()
         }
     }

Diff for: alloc/src/collections/btree/map.rs

@@ -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();

Diff for: alloc/src/collections/btree/mod.rs

@@ -12,11 +12,3 @@ mod search;
 pub mod set;
 mod set_val;
 mod split;
-
-trait Recover<Q: ?Sized> {
-    type Key;
-
-    fn get(&self, key: &Q) -> Option<&Self::Key>;
-    fn take(&mut self, key: &Q) -> Option<Self::Key>;
-    fn replace(&mut self, key: Self::Key) -> Option<Self::Key>;
-}

Diff for: alloc/src/collections/btree/set.rs

@@ -7,7 +7,6 @@ use core::iter::{FusedIterator, Peekable};
 use core::mem::ManuallyDrop;
 use core::ops::{BitAnd, BitOr, BitXor, Bound, RangeBounds, Sub};
 
-use super::Recover;
 use super::map::{BTreeMap, Keys};
 use super::merge_iter::MergeIterInner;
 use super::set_val::SetValZST;
@@ -635,7 +634,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
         T: Borrow<Q> + Ord,
         Q: Ord,
     {
-        Recover::get(&self.map, value)
+        self.map.get_key_value(value).map(|(k, _)| k)
     }
 
     /// Returns `true` if `self` has no elements in common with `other`.
@@ -926,7 +925,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     where
         T: Ord,
     {
-        Recover::replace(&mut self.map, value)
+        self.map.replace(value)
     }
 
     /// If the set contains an element equal to the value, removes it from the
@@ -978,7 +977,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
         T: Borrow<Q> + Ord,
         Q: Ord,
     {
-        Recover::take(&mut self.map, value)
+        self.map.remove_entry(value).map(|(k, _)| k)
     }
 
     /// Retains only the elements specified by the predicate.

Diff for: alloc/src/collections/btree/set_val.rs

@@ -3,14 +3,14 @@
 /// * `BTreeMap<T, ()>` (possible user-defined map)
 /// * `BTreeMap<T, SetValZST>` (internal set representation)
 #[derive(Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Clone, Default)]
-pub struct SetValZST;
+pub(super) struct SetValZST;
 
 /// A trait to differentiate between `BTreeMap` and `BTreeSet` values.
 /// Returns `true` only for type `SetValZST`, `false` for all other types (blanket implementation).
 /// `TypeId` requires a `'static` lifetime, use of this trait avoids that restriction.
 ///
 /// [`TypeId`]: std::any::TypeId
-pub trait IsSetVal {
+pub(super) trait IsSetVal {
     fn is_set_val() -> bool;
 }
 

Diff for: alloc/src/rc.rs

@@ -1876,7 +1876,7 @@ impl<T: ?Sized + CloneToUninit, A: Allocator + Clone> Rc<T, A> {
             // Initialize with clone of this.
             let initialized_clone = unsafe {
                 // Clone. If the clone panics, `in_progress` will be dropped and clean up.
-                this_data_ref.clone_to_uninit(in_progress.data_ptr());
+                this_data_ref.clone_to_uninit(in_progress.data_ptr().cast());
                 // Cast type of pointer, now that it is initialized.
                 in_progress.into_rc()
             };

Diff for: alloc/src/sync.rs

@@ -2272,7 +2272,7 @@ impl<T: ?Sized + CloneToUninit, A: Allocator + Clone> Arc<T, A> {
 
             let initialized_clone = unsafe {
                 // Clone. If the clone panics, `in_progress` will be dropped and clean up.
-                this_data_ref.clone_to_uninit(in_progress.data_ptr());
+                this_data_ref.clone_to_uninit(in_progress.data_ptr().cast());
                 // Cast type of pointer, now that it is initialized.
                 in_progress.into_arc()
             };

Diff for: core/src/clone.rs

@@ -232,20 +232,20 @@ pub struct AssertParamIsCopy<T: Copy + ?Sized> {
 pub unsafe trait CloneToUninit {
     /// Performs copy-assignment from `self` to `dst`.
     ///
-    /// This is analogous to `std::ptr::write(dst, self.clone())`,
+    /// This is analogous to `std::ptr::write(dst.cast(), self.clone())`,
     /// except that `self` may be a dynamically-sized type ([`!Sized`](Sized)).
     ///
     /// Before this function is called, `dst` may point to uninitialized memory.
     /// After this function is called, `dst` will point to initialized memory; it will be
-    /// sound to create a `&Self` reference from the pointer.
+    /// sound to create a `&Self` reference from the pointer with the [pointer metadata]
+    /// from `self`.
     ///
     /// # Safety
     ///
     /// Behavior is undefined if any of the following conditions are violated:
     ///
-    /// * `dst` must be [valid] for writes.
-    /// * `dst` must be properly aligned.
-    /// * `dst` must have the same [pointer metadata] (slice length or `dyn` vtable) as `self`.
+    /// * `dst` must be [valid] for writes for `std::mem::size_of_val(self)` bytes.
+    /// * `dst` must be properly aligned to `std::mem::align_of_val(self)`.
     ///
     /// [valid]: crate::ptr#safety
     /// [pointer metadata]: crate::ptr::metadata()
@@ -266,23 +266,24 @@ pub unsafe trait CloneToUninit {
     /// that might have already been created. (For example, if a `[Foo]` of length 3 is being
     /// cloned, and the second of the three calls to `Foo::clone()` unwinds, then the first `Foo`
     /// cloned should be dropped.)
-    unsafe fn clone_to_uninit(&self, dst: *mut Self);
+    unsafe fn clone_to_uninit(&self, dst: *mut u8);
 }
 
 #[unstable(feature = "clone_to_uninit", issue = "126799")]
 unsafe impl<T: Clone> CloneToUninit for T {
     #[inline]
-    unsafe fn clone_to_uninit(&self, dst: *mut Self) {
+    unsafe fn clone_to_uninit(&self, dst: *mut u8) {
         // SAFETY: we're calling a specialization with the same contract
-        unsafe { <T as self::uninit::CopySpec>::clone_one(self, dst) }
+        unsafe { <T as self::uninit::CopySpec>::clone_one(self, dst.cast::<T>()) }
     }
 }
 
 #[unstable(feature = "clone_to_uninit", issue = "126799")]
 unsafe impl<T: Clone> CloneToUninit for [T] {
     #[inline]
     #[cfg_attr(debug_assertions, track_caller)]
-    unsafe fn clone_to_uninit(&self, dst: *mut Self) {
+    unsafe fn clone_to_uninit(&self, dst: *mut u8) {
+        let dst: *mut [T] = dst.with_metadata_of(self);
         // SAFETY: we're calling a specialization with the same contract
         unsafe { <T as self::uninit::CopySpec>::clone_slice(self, dst) }
     }
@@ -292,21 +293,21 @@ unsafe impl<T: Clone> CloneToUninit for [T] {
 unsafe impl CloneToUninit for str {
     #[inline]
     #[cfg_attr(debug_assertions, track_caller)]
-    unsafe fn clone_to_uninit(&self, dst: *mut Self) {
+    unsafe fn clone_to_uninit(&self, dst: *mut u8) {
         // SAFETY: str is just a [u8] with UTF-8 invariant
-        unsafe { self.as_bytes().clone_to_uninit(dst as *mut [u8]) }
+        unsafe { self.as_bytes().clone_to_uninit(dst) }
     }
 }
 
 #[unstable(feature = "clone_to_uninit", issue = "126799")]
 unsafe impl CloneToUninit for crate::ffi::CStr {
     #[cfg_attr(debug_assertions, track_caller)]
-    unsafe fn clone_to_uninit(&self, dst: *mut Self) {
+    unsafe fn clone_to_uninit(&self, dst: *mut u8) {
         // SAFETY: For now, CStr is just a #[repr(trasnsparent)] [c_char] with some invariants.
         // And we can cast [c_char] to [u8] on all supported platforms (see: to_bytes_with_nul).
-        // The pointer metadata properly preserves the length (NUL included).
+        // The pointer metadata properly preserves the length (so NUL is also copied).
         // See: `cstr_metadata_is_length_with_nul` in tests.
-        unsafe { self.to_bytes_with_nul().clone_to_uninit(dst as *mut [u8]) }
+        unsafe { self.to_bytes_with_nul().clone_to_uninit(dst) }
     }
 }
 

Diff for: core/src/fmt/float.rs

@@ -13,7 +13,7 @@ macro_rules! impl_general_format {
     ($($t:ident)*) => {
         $(impl GeneralFormat for $t {
             fn already_rounded_value_should_use_exponential(&self) -> bool {
-                let abs = $t::abs_private(*self);
+                let abs = $t::abs(*self);
                 (abs != 0.0 && abs < 1e-4) || abs >= 1e+16
             }
         })*