rust: alloc: remove our fork of the `alloc` crate

It is not used anymore as `VecExt` now provides the functionality we
depend on.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-5-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

8 files changed, 0 insertions, 4985 deletions

diff --git a/rust/alloc/vec/drain.rs b/rust/alloc/vec/drain.rs
deleted file mode 100644
index 78177a9e2ad0..000000000000
--- a/rust/alloc/vec/drain.rs
+++ /dev/null
@@ -1,255 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0 OR MIT
-
-use crate::alloc::{Allocator, Global};
-use core::fmt;
-use core::iter::{FusedIterator, TrustedLen};
-use core::mem::{self, ManuallyDrop, SizedTypeProperties};
-use core::ptr::{self, NonNull};
-use core::slice::{self};
-
-use super::Vec;
-
-/// A draining iterator for `Vec<T>`.
-///
-/// This `struct` is created by [`Vec::drain`].
-/// See its documentation for more.
-///
-/// # Example
-///
-/// ```
-/// let mut v = vec![0, 1, 2];
-/// let iter: std::vec::Drain<'_, _> = v.drain(..);
-/// ```
-#[stable(feature = "drain", since = "1.6.0")]
-pub struct Drain<
-    'a,
-    T: 'a,
-    #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + 'a = Global,
-> {
-    /// Index of tail to preserve
-    pub(super) tail_start: usize,
-    /// Length of tail
-    pub(super) tail_len: usize,
-    /// Current remaining range to remove
-    pub(super) iter: slice::Iter<'a, T>,
-    pub(super) vec: NonNull<Vec<T, A>>,
-}
-
-#[stable(feature = "collection_debug", since = "1.17.0")]
-impl<T: fmt::Debug, A: Allocator> fmt::Debug for Drain<'_, T, A> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_tuple("Drain").field(&self.iter.as_slice()).finish()
-    }
-}
-
-impl<'a, T, A: Allocator> Drain<'a, T, A> {
-    /// Returns the remaining items of this iterator as a slice.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let mut vec = vec!['a', 'b', 'c'];
-    /// let mut drain = vec.drain(..);
-    /// assert_eq!(drain.as_slice(), &['a', 'b', 'c']);
-    /// let _ = drain.next().unwrap();
-    /// assert_eq!(drain.as_slice(), &['b', 'c']);
-    /// ```
-    #[must_use]
-    #[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
-    pub fn as_slice(&self) -> &[T] {
-        self.iter.as_slice()
-    }
-
-    /// Returns a reference to the underlying allocator.
-    #[unstable(feature = "allocator_api", issue = "32838")]
-    #[must_use]
-    #[inline]
-    pub fn allocator(&self) -> &A {
-        unsafe { self.vec.as_ref().allocator() }
-    }
-
-    /// Keep unyielded elements in the source `Vec`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(drain_keep_rest)]
-    ///
-    /// let mut vec = vec!['a', 'b', 'c'];
-    /// let mut drain = vec.drain(..);
-    ///
-    /// assert_eq!(drain.next().unwrap(), 'a');
-    ///
-    /// // This call keeps 'b' and 'c' in the vec.
-    /// drain.keep_rest();
-    ///
-    /// // If we wouldn't call `keep_rest()`,
-    /// // `vec` would be empty.
-    /// assert_eq!(vec, ['b', 'c']);
-    /// ```
-    #[unstable(feature = "drain_keep_rest", issue = "101122")]
-    pub fn keep_rest(self) {
-        // At this moment layout looks like this:
-        //
-        // [head] [yielded by next] [unyielded] [yielded by next_back] [tail]
-        //        ^-- start         \_________/-- unyielded_len        \____/-- self.tail_len
-        //                          ^-- unyielded_ptr                  ^-- tail
-        //
-        // Normally `Drop` impl would drop [unyielded] and then move [tail] to the `start`.
-        // Here we want to
-        // 1. Move [unyielded] to `start`
-        // 2. Move [tail] to a new start at `start + len(unyielded)`
-        // 3. Update length of the original vec to `len(head) + len(unyielded) + len(tail)`
-        //    a. In case of ZST, this is the only thing we want to do
-        // 4. Do *not* drop self, as everything is put in a consistent state already, there is nothing to do
-        let mut this = ManuallyDrop::new(self);
-
-        unsafe {
-            let source_vec = this.vec.as_mut();
-
-            let start = source_vec.len();
-            let tail = this.tail_start;
-
-            let unyielded_len = this.iter.len();
-            let unyielded_ptr = this.iter.as_slice().as_ptr();
-
-            // ZSTs have no identity, so we don't need to move them around.
-            if !T::IS_ZST {
-                let start_ptr = source_vec.as_mut_ptr().add(start);
-
-                // memmove back unyielded elements
-                if unyielded_ptr != start_ptr {
-                    let src = unyielded_ptr;
-                    let dst = start_ptr;
-
-                    ptr::copy(src, dst, unyielded_len);
-                }
-
-                // memmove back untouched tail
-                if tail != (start + unyielded_len) {
-                    let src = source_vec.as_ptr().add(tail);
-                    let dst = start_ptr.add(unyielded_len);
-                    ptr::copy(src, dst, this.tail_len);
-                }
-            }
-
-            source_vec.set_len(start + unyielded_len + this.tail_len);
-        }
-    }
-}
-
-#[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
-impl<'a, T, A: Allocator> AsRef<[T]> for Drain<'a, T, A> {
-    fn as_ref(&self) -> &[T] {
-        self.as_slice()
-    }
-}
-
-#[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<T: Sync, A: Sync + Allocator> Sync for Drain<'_, T, A> {}
-#[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<T: Send, A: Send + Allocator> Send for Drain<'_, T, A> {}
-
-#[stable(feature = "drain", since = "1.6.0")]
-impl<T, A: Allocator> Iterator for Drain<'_, T, A> {
-    type Item = T;
-
-    #[inline]
-    fn next(&mut self) -> Option<T> {
-        self.iter.next().map(|elt| unsafe { ptr::read(elt as *const _) })
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
-    }
-}
-
-#[stable(feature = "drain", since = "1.6.0")]
-impl<T, A: Allocator> DoubleEndedIterator for Drain<'_, T, A> {
-    #[inline]
-    fn next_back(&mut self) -> Option<T> {
-        self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) })
-    }
-}
-
-#[stable(feature = "drain", since = "1.6.0")]
-impl<T, A: Allocator> Drop for Drain<'_, T, A> {
-    fn drop(&mut self) {
-        /// Moves back the un-`Drain`ed elements to restore the original `Vec`.
-        struct DropGuard<'r, 'a, T, A: Allocator>(&'r mut Drain<'a, T, A>);
-
-        impl<'r, 'a, T, A: Allocator> Drop for DropGuard<'r, 'a, T, A> {
-            fn drop(&mut self) {
-                if self.0.tail_len > 0 {
-                    unsafe {
-                        let source_vec = self.0.vec.as_mut();
-                        // memmove back untouched tail, update to new length
-                        let start = source_vec.len();
-                        let tail = self.0.tail_start;
-                        if tail != start {
-                            let src = source_vec.as_ptr().add(tail);
-                            let dst = source_vec.as_mut_ptr().add(start);
-                            ptr::copy(src, dst, self.0.tail_len);
-                        }
-                        source_vec.set_len(start + self.0.tail_len);
-                    }
-                }
-            }
-        }
-
-        let iter = mem::take(&mut self.iter);
-        let drop_len = iter.len();
-
-        let mut vec = self.vec;
-
-        if T::IS_ZST {
-            // ZSTs have no identity, so we don't need to move them around, we only need to drop the correct amount.
-            // this can be achieved by manipulating the Vec length instead of moving values out from `iter`.
-            unsafe {
-                let vec = vec.as_mut();
-                let old_len = vec.len();
-                vec.set_len(old_len + drop_len + self.tail_len);
-                vec.truncate(old_len + self.tail_len);
-            }
-
-            return;
-        }
-
-        // ensure elements are moved back into their appropriate places, even when drop_in_place panics
-        let _guard = DropGuard(self);
-
-        if drop_len == 0 {
-            return;
-        }
-
-        // as_slice() must only be called when iter.len() is > 0 because
-        // it also gets touched by vec::Splice which may turn it into a dangling pointer
-        // which would make it and the vec pointer point to different allocations which would
-        // lead to invalid pointer arithmetic below.
-        let drop_ptr = iter.as_slice().as_ptr();
-
-        unsafe {
-            // drop_ptr comes from a slice::Iter which only gives us a &[T] but for drop_in_place
-            // a pointer with mutable provenance is necessary. Therefore we must reconstruct
-            // it from the original vec but also avoid creating a &mut to the front since that could
-            // invalidate raw pointers to it which some unsafe code might rely on.
-            let vec_ptr = vec.as_mut().as_mut_ptr();
-            let drop_offset = drop_ptr.sub_ptr(vec_ptr);
-            let to_drop = ptr::slice_from_raw_parts_mut(vec_ptr.add(drop_offset), drop_len);
-            ptr::drop_in_place(to_drop);
-        }
-    }
-}
-
-#[stable(feature = "drain", since = "1.6.0")]
-impl<T, A: Allocator> ExactSizeIterator for Drain<'_, T, A> {
-    fn is_empty(&self) -> bool {
-        self.iter.is_empty()
-    }
-}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<T, A: Allocator> TrustedLen for Drain<'_, T, A> {}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<T, A: Allocator> FusedIterator for Drain<'_, T, A> {}
diff --git a/rust/alloc/vec/extract_if.rs b/rust/alloc/vec/extract_if.rs
deleted file mode 100644
index f314a51d4d3d..000000000000
--- a/rust/alloc/vec/extract_if.rs
+++ /dev/null
@@ -1,115 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0 OR MIT
-
-use crate::alloc::{Allocator, Global};
-use core::ptr;
-use core::slice;
-
-use super::Vec;
-
-/// An iterator which uses a closure to determine if an element should be removed.
-///
-/// This struct is created by [`Vec::extract_if`].
-/// See its documentation for more.
-///
-/// # Example
-///
-/// ```
-/// #![feature(extract_if)]
-///
-/// let mut v = vec![0, 1, 2];
-/// let iter: std::vec::ExtractIf<'_, _, _> = v.extract_if(|x| *x % 2 == 0);
-/// ```
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
-#[derive(Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-pub struct ExtractIf<
-    'a,
-    T,
-    F,
-    #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
-> where
-    F: FnMut(&mut T) -> bool,
-{
-    pub(super) vec: &'a mut Vec<T, A>,
-    /// The index of the item that will be inspected by the next call to `next`.
-    pub(super) idx: usize,
-    /// The number of items that have been drained (removed) thus far.
-    pub(super) del: usize,
-    /// The original length of `vec` prior to draining.
-    pub(super) old_len: usize,
-    /// The filter test predicate.
-    pub(super) pred: F,
-}
-
-impl<T, F, A: Allocator> ExtractIf<'_, T, F, A>
-where
-    F: FnMut(&mut T) -> bool,
-{
-    /// Returns a reference to the underlying allocator.
-    #[unstable(feature = "allocator_api", issue = "32838")]
-    #[inline]
-    pub fn allocator(&self) -> &A {
-        self.vec.allocator()
-    }
-}
-
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
-impl<T, F, A: Allocator> Iterator for ExtractIf<'_, T, F, A>
-where
-    F: FnMut(&mut T) -> bool,
-{
-    type Item = T;
-
-    fn next(&mut self) -> Option<T> {
-        unsafe {
-            while self.idx < self.old_len {
-                let i = self.idx;
-                let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len);
-                let drained = (self.pred)(&mut v[i]);
-                // Update the index *after* the predicate is called. If the index
-                // is updated prior and the predicate panics, the element at this
-                // index would be leaked.
-                self.idx += 1;
-                if drained {
-                    self.del += 1;
-                    return Some(ptr::read(&v[i]));
-                } else if self.del > 0 {
-                    let del = self.del;
-                    let src: *const T = &v[i];
-                    let dst: *mut T = &mut v[i - del];
-                    ptr::copy_nonoverlapping(src, dst, 1);
-                }
-            }
-            None
-        }
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        (0, Some(self.old_len - self.idx))
-    }
-}
-
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
-impl<T, F, A: Allocator> Drop for ExtractIf<'_, T, F, A>
-where
-    F: FnMut(&mut T) -> bool,
-{
-    fn drop(&mut self) {
-        unsafe {
-            if self.idx < self.old_len && self.del > 0 {
-                // This is a pretty messed up state, and there isn't really an
-                // obviously right thing to do. We don't want to keep trying
-                // to execute `pred`, so we just backshift all the unprocessed
-                // elements and tell the vec that they still exist. The backshift
-                // is required to prevent a double-drop of the last successfully
-                // drained item prior to a panic in the predicate.
-                let ptr = self.vec.as_mut_ptr();
-                let src = ptr.add(self.idx);
-                let dst = src.sub(self.del);
-                let tail_len = self.old_len - self.idx;
-                src.copy_to(dst, tail_len);
-            }
-            self.vec.set_len(self.old_len - self.del);
-        }
-    }
-}
diff --git a/rust/alloc/vec/into_iter.rs b/rust/alloc/vec/into_iter.rs
deleted file mode 100644
index 0f11744c44b3..000000000000
--- a/rust/alloc/vec/into_iter.rs
+++ /dev/null
@@ -1,484 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0 OR MIT
-
-#[cfg(not(no_global_oom_handling))]
-use super::AsVecIntoIter;
-use crate::alloc::{Allocator, Global};
-#[cfg(not(no_global_oom_handling))]
-use crate::collections::VecDeque;
-use crate::raw_vec::RawVec;
-use core::array;
-use core::fmt;
-use core::iter::{
-    FusedIterator, InPlaceIterable, SourceIter, TrustedFused, TrustedLen,
-    TrustedRandomAccessNoCoerce,
-};
-use core::marker::PhantomData;
-use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
-use core::num::NonZeroUsize;
-#[cfg(not(no_global_oom_handling))]
-use core::ops::Deref;
-use core::ptr::{self, NonNull};
-use core::slice::{self};
-
-macro non_null {
-    (mut $place:expr, $t:ident) => {{
-        #![allow(unused_unsafe)] // we're sometimes used within an unsafe block
-        unsafe { &mut *(ptr::addr_of_mut!($place) as *mut NonNull<$t>) }
-    }},
-    ($place:expr, $t:ident) => {{
-        #![allow(unused_unsafe)] // we're sometimes used within an unsafe block
-        unsafe { *(ptr::addr_of!($place) as *const NonNull<$t>) }
-    }},
-}
-
-/// An iterator that moves out of a vector.
-///
-/// This `struct` is created by the `into_iter` method on [`Vec`](super::Vec)
-/// (provided by the [`IntoIterator`] trait).
-///
-/// # Example
-///
-/// ```
-/// let v = vec![0, 1, 2];
-/// let iter: std::vec::IntoIter<_> = v.into_iter();
-/// ```
-#[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_insignificant_dtor]
-pub struct IntoIter<
-    T,
-    #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
-> {
-    pub(super) buf: NonNull<T>,
-    pub(super) phantom: PhantomData<T>,
-    pub(super) cap: usize,
-    // the drop impl reconstructs a RawVec from buf, cap and alloc
-    // to avoid dropping the allocator twice we need to wrap it into ManuallyDrop
-    pub(super) alloc: ManuallyDrop<A>,
-    pub(super) ptr: NonNull<T>,
-    /// If T is a ZST, this is actually ptr+len. This encoding is picked so that
-    /// ptr == end is a quick test for the Iterator being empty, that works
-    /// for both ZST and non-ZST.
-    /// For non-ZSTs the pointer is treated as `NonNull<T>`
-    pub(super) end: *const T,
-}
-
-#[stable(feature = "vec_intoiter_debug", since = "1.13.0")]
-impl<T: fmt::Debug, A: Allocator> fmt::Debug for IntoIter<T, A> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_tuple("IntoIter").field(&self.as_slice()).finish()
-    }
-}
-
-impl<T, A: Allocator> IntoIter<T, A> {
-    /// Returns the remaining items of this iterator as a slice.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let vec = vec!['a', 'b', 'c'];
-    /// let mut into_iter = vec.into_iter();
-    /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
-    /// let _ = into_iter.next().unwrap();
-    /// assert_eq!(into_iter.as_slice(), &['b', 'c']);
-    /// ```
-    #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
-    pub fn as_slice(&self) -> &[T] {
-        unsafe { slice::from_raw_parts(self.ptr.as_ptr(), self.len()) }
-    }
-
-    /// Returns the remaining items of this iterator as a mutable slice.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let vec = vec!['a', 'b', 'c'];
-    /// let mut into_iter = vec.into_iter();
-    /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
-    /// into_iter.as_mut_slice()[2] = 'z';
-    /// assert_eq!(into_iter.next().unwrap(), 'a');
-    /// assert_eq!(into_iter.next().unwrap(), 'b');
-    /// assert_eq!(into_iter.next().unwrap(), 'z');
-    /// ```
-    #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
-    pub fn as_mut_slice(&mut self) -> &mut [T] {
-        unsafe { &mut *self.as_raw_mut_slice() }
-    }
-
-    /// Returns a reference to the underlying allocator.
-    #[unstable(feature = "allocator_api", issue = "32838")]
-    #[inline]
-    pub fn allocator(&self) -> &A {
-        &self.alloc
-    }
-
-    fn as_raw_mut_slice(&mut self) -> *mut [T] {
-        ptr::slice_from_raw_parts_mut(self.ptr.as_ptr(), self.len())
-    }
-
-    /// Drops remaining elements and relinquishes the backing allocation.
-    /// This method guarantees it won't panic before relinquishing
-    /// the backing allocation.
-    ///
-    /// This is roughly equivalent to the following, but more efficient
-    ///
-    /// ```
-    /// # let mut into_iter = Vec::<u8>::with_capacity(10).into_iter();
-    /// let mut into_iter = std::mem::replace(&mut into_iter, Vec::new().into_iter());
-    /// (&mut into_iter).for_each(drop);
-    /// std::mem::forget(into_iter);
-    /// ```
-    ///
-    /// This method is used by in-place iteration, refer to the vec::in_place_collect
-    /// documentation for an overview.
-    #[cfg(not(no_global_oom_handling))]
-    pub(super) fn forget_allocation_drop_remaining(&mut self) {
-        let remaining = self.as_raw_mut_slice();
-
-        // overwrite the individual fields instead of creating a new
-        // struct and then overwriting &mut self.
-        // this creates less assembly
-        self.cap = 0;
-        self.buf = unsafe { NonNull::new_unchecked(RawVec::NEW.ptr()) };
-        self.ptr = self.buf;
-        self.end = self.buf.as_ptr();
-
-        // Dropping the remaining elements can panic, so this needs to be
-        // done only after updating the other fields.
-        unsafe {
-            ptr::drop_in_place(remaining);
-        }
-    }
-
-    /// Forgets to Drop the remaining elements while still allowing the backing allocation to be freed.
-    pub(crate) fn forget_remaining_elements(&mut self) {
-        // For the ZST case, it is crucial that we mutate `end` here, not `ptr`.
-        // `ptr` must stay aligned, while `end` may be unaligned.
-        self.end = self.ptr.as_ptr();
-    }
-
-    #[cfg(not(no_global_oom_handling))]
-    #[inline]
-    pub(crate) fn into_vecdeque(self) -> VecDeque<T, A> {
-        // Keep our `Drop` impl from dropping the elements and the allocator
-        let mut this = ManuallyDrop::new(self);
-
-        // SAFETY: This allocation originally came from a `Vec`, so it passes
-        // all those checks. We have `this.buf` ≤ `this.ptr` ≤ `this.end`,
-        // so the `sub_ptr`s below cannot wrap, and will produce a well-formed
-        // range. `end` ≤ `buf + cap`, so the range will be in-bounds.
-        // Taking `alloc` is ok because nothing else is going to look at it,
-        // since our `Drop` impl isn't going to run so there's no more code.
-        unsafe {
-            let buf = this.buf.as_ptr();
-            let initialized = if T::IS_ZST {
-                // All the pointers are the same for ZSTs, so it's fine to
-                // say that they're all at the beginning of the "allocation".
-                0..this.len()
-            } else {
-                this.ptr.sub_ptr(this.buf)..this.end.sub_ptr(buf)
-            };
-            let cap = this.cap;
-            let alloc = ManuallyDrop::take(&mut this.alloc);
-            VecDeque::from_contiguous_raw_parts_in(buf, initialized, cap, alloc)
-        }
-    }
-}
-
-#[stable(feature = "vec_intoiter_as_ref", since = "1.46.0")]
-impl<T, A: Allocator> AsRef<[T]> for IntoIter<T, A> {
-    fn as_ref(&self) -> &[T] {
-        self.as_slice()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<T: Send, A: Allocator + Send> Send for IntoIter<T, A> {}
-#[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<T: Sync, A: Allocator + Sync> Sync for IntoIter<T, A> {}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A: Allocator> Iterator for IntoIter<T, A> {
-    type Item = T;
-
-    #[inline]
-    fn next(&mut self) -> Option<T> {
-        if T::IS_ZST {
-            if self.ptr.as_ptr() == self.end as *mut _ {
-                None
-            } else {
-                // `ptr` has to stay where it is to remain aligned, so we reduce the length by 1 by
-                // reducing the `end`.
-                self.end = self.end.wrapping_byte_sub(1);
-
-                // Make up a value of this ZST.
-                Some(unsafe { mem::zeroed() })
-            }
-        } else {
-            if self.ptr == non_null!(self.end, T) {
-                None
-            } else {
-                let old = self.ptr;
-                self.ptr = unsafe { old.add(1) };
-
-                Some(unsafe { ptr::read(old.as_ptr()) })
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let exact = if T::IS_ZST {
-            self.end.addr().wrapping_sub(self.ptr.as_ptr().addr())
-        } else {
-            unsafe { non_null!(self.end, T).sub_ptr(self.ptr) }
-        };
-        (exact, Some(exact))
-    }
-
-    #[inline]
-    fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
-        let step_size = self.len().min(n);
-        let to_drop = ptr::slice_from_raw_parts_mut(self.ptr.as_ptr(), step_size);
-        if T::IS_ZST {
-            // See `next` for why we sub `end` here.
-            self.end = self.end.wrapping_byte_sub(step_size);
-        } else {
-            // SAFETY: the min() above ensures that step_size is in bounds
-            self.ptr = unsafe { self.ptr.add(step_size) };
-        }
-        // SAFETY: the min() above ensures that step_size is in bounds
-        unsafe {
-            ptr::drop_in_place(to_drop);
-        }
-        NonZeroUsize::new(n - step_size).map_or(Ok(()), Err)
-    }
-
-    #[inline]
-    fn count(self) -> usize {
-        self.len()
-    }
-
-    #[inline]
-    fn next_chunk<const N: usize>(&mut self) -> Result<[T; N], core::array::IntoIter<T, N>> {
-        let mut raw_ary = MaybeUninit::uninit_array();
-
-        let len = self.len();
-
-        if T::IS_ZST {
-            if len < N {
-                self.forget_remaining_elements();
-                // Safety: ZSTs can be conjured ex nihilo, only the amount has to be correct
-                return Err(unsafe { array::IntoIter::new_unchecked(raw_ary, 0..len) });
-            }
-
-            self.end = self.end.wrapping_byte_sub(N);
-            // Safety: ditto
-            return Ok(unsafe { raw_ary.transpose().assume_init() });
-        }
-
-        if len < N {
-            // Safety: `len` indicates that this many elements are available and we just checked that
-            // it fits into the array.
-            unsafe {
-                ptr::copy_nonoverlapping(self.ptr.as_ptr(), raw_ary.as_mut_ptr() as *mut T, len);
-                self.forget_remaining_elements();
-                return Err(array::IntoIter::new_unchecked(raw_ary, 0..len));
-            }
-        }
-
-        // Safety: `len` is larger than the array size. Copy a fixed amount here to fully initialize
-        // the array.
-        return unsafe {
-            ptr::copy_nonoverlapping(self.ptr.as_ptr(), raw_ary.as_mut_ptr() as *mut T, N);
-            self.ptr = self.ptr.add(N);
-            Ok(raw_ary.transpose().assume_init())
-        };
-    }
-
-    unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> Self::Item
-    where
-        Self: TrustedRandomAccessNoCoerce,
-    {
-        // SAFETY: the caller must guarantee that `i` is in bounds of the
-        // `Vec<T>`, so `i` cannot overflow an `isize`, and the `self.ptr.add(i)`
-        // is guaranteed to pointer to an element of the `Vec<T>` and
-        // thus guaranteed to be valid to dereference.
-        //
-        // Also note the implementation of `Self: TrustedRandomAccess` requires
-        // that `T: Copy` so reading elements from the buffer doesn't invalidate
-        // them for `Drop`.
-        unsafe { if T::IS_ZST { mem::zeroed() } else { self.ptr.add(i).read() } }
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> {
-    #[inline]
-    fn next_back(&mut self) -> Option<T> {
-        if T::IS_ZST {
-            if self.end as *mut _ == self.ptr.as_ptr() {
-                None
-            } else {
-                // See above for why 'ptr.offset' isn't used
-                self.end = self.end.wrapping_byte_sub(1);
-
-                // Make up a value of this ZST.
-                Some(unsafe { mem::zeroed() })
-            }
-        } else {
-            if non_null!(self.end, T) == self.ptr {
-                None
-            } else {
-                let new_end = unsafe { non_null!(self.end, T).sub(1) };
-                *non_null!(mut self.end, T) = new_end;
-
-                Some(unsafe { ptr::read(new_end.as_ptr()) })
-            }
-        }
-    }
-
-    #[inline]
-    fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
-        let step_size = self.len().min(n);
-        if T::IS_ZST {
-            // SAFETY: same as for advance_by()
-            self.end = self.end.wrapping_byte_sub(step_size);
-        } else {
-            // SAFETY: same as for advance_by()
-            self.end = unsafe { self.end.sub(step_size) };
-        }
-        let to_drop = ptr::slice_from_raw_parts_mut(self.end as *mut T, step_size);
-        // SAFETY: same as for advance_by()
-        unsafe {
-            ptr::drop_in_place(to_drop);
-        }
-        NonZeroUsize::new(n - step_size).map_or(Ok(()), Err)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A: Allocator> ExactSizeIterator for IntoIter<T, A> {
-    fn is_empty(&self) -> bool {
-        if T::IS_ZST {
-            self.ptr.as_ptr() == self.end as *mut _
-        } else {
-            self.ptr == non_null!(self.end, T)
-        }
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<T, A: Allocator> FusedIterator for IntoIter<T, A> {}
-
-#[doc(hidden)]
-#[unstable(issue = "none", feature = "trusted_fused")]
-unsafe impl<T, A: Allocator> TrustedFused for IntoIter<T, A> {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<T, A: Allocator> TrustedLen for IntoIter<T, A> {}
-
-#[stable(feature = "default_iters", since = "1.70.0")]
-impl<T, A> Default for IntoIter<T, A>
-where
-    A: Allocator + Default,
-{
-    /// Creates an empty `vec::IntoIter`.
-    ///
-    /// ```
-    /// # use std::vec;
-    /// let iter: vec::IntoIter<u8> = Default::default();
-    /// assert_eq!(iter.len(), 0);
-    /// assert_eq!(iter.as_slice(), &[]);
-    /// ```
-    fn default() -> Self {
-        super::Vec::new_in(Default::default()).into_iter()
-    }
-}
-
-#[doc(hidden)]
-#[unstable(issue = "none", feature = "std_internals")]
-#[rustc_unsafe_specialization_marker]
-pub trait NonDrop {}
-
-// T: Copy as approximation for !Drop since get_unchecked does not advance self.ptr
-// and thus we can't implement drop-handling
-#[unstable(issue = "none", feature = "std_internals")]
-impl<T: Copy> NonDrop for T {}
-
-#[doc(hidden)]
-#[unstable(issue = "none", feature = "std_internals")]
-// TrustedRandomAccess (without NoCoerce) must not be implemented because
-// subtypes/supertypes of `T` might not be `NonDrop`
-unsafe impl<T, A: Allocator> TrustedRandomAccessNoCoerce for IntoIter<T, A>
-where
-    T: NonDrop,
-{
-    const MAY_HAVE_SIDE_EFFECT: bool = false;
-}
-
-#[cfg(not(no_global_oom_handling))]
-#[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
-impl<T: Clone, A: Allocator + Clone> Clone for IntoIter<T, A> {
-    #[cfg(not(test))]
-    fn clone(&self) -> Self {
-        self.as_slice().to_vec_in(self.alloc.deref().clone()).into_iter()
-    }
-    #[cfg(test)]
-    fn clone(&self) -> Self {
-        crate::slice::to_vec(self.as_slice(), self.alloc.deref().clone()).into_iter()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
-    fn drop(&mut self) {
-        struct DropGuard<'a, T, A: Allocator>(&'a mut IntoIter<T, A>);
-
-        impl<T, A: Allocator> Drop for DropGuard<'_, T, A> {
-            fn drop(&mut self) {
-                unsafe {
-                    // `IntoIter::alloc` is not used anymore after this and will be dropped by RawVec
-                    let alloc = ManuallyDrop::take(&mut self.0.alloc);
-                    // RawVec handles deallocation
-                    let _ = RawVec::from_raw_parts_in(self.0.buf.as_ptr(), self.0.cap, alloc);
-                }
-            }
-        }
-
-        let guard = DropGuard(self);
-        // destroy the remaining elements
-        unsafe {
-            ptr::drop_in_place(guard.0.as_raw_mut_slice());
-        }
-        // now `guard` will be dropped and do the rest
-    }
-}
-
-// In addition to the SAFETY invariants of the following three unsafe traits
-// also refer to the vec::in_place_collect module documentation to get an overview
-#[unstable(issue = "none", feature = "inplace_iteration")]
-#[doc(hidden)]
-unsafe impl<T, A: Allocator> InPlaceIterable for IntoIter<T, A> {
-    const EXPAND_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
-    const MERGE_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
-}
-
-#[unstable(issue = "none", feature = "inplace_iteration")]
-#[doc(hidden)]
-unsafe impl<T, A: Allocator> SourceIter for IntoIter<T, A> {
-    type Source = Self;
-
-    #[inline]
-    unsafe fn as_inner(&mut self) -> &mut Self::Source {
-        self
-    }
-}
-
-#[cfg(not(no_global_oom_handling))]
-unsafe impl<T> AsVecIntoIter for IntoIter<T> {
-    type Item = T;
-
-    fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item> {
-        self
-    }
-}
diff --git a/rust/alloc/vec/is_zero.rs b/rust/alloc/vec/is_zero.rs
deleted file mode 100644
index d928dcf90e80..000000000000
--- a/rust/alloc/vec/is_zero.rs
+++ /dev/null
@@ -1,204 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0 OR MIT
-
-use core::num::{Saturating, Wrapping};
-
-use crate::boxed::Box;
-
-#[rustc_specialization_trait]
-pub(super) unsafe trait IsZero {
-    /// Whether this value's representation is all zeros,
-    /// or can be represented with all zeroes.
-    fn is_zero(&self) -> bool;
-}
-
-macro_rules! impl_is_zero {
-    ($t:ty, $is_zero:expr) => {
-        unsafe impl IsZero for $t {
-            #[inline]
-            fn is_zero(&self) -> bool {
-                $is_zero(*self)
-            }
-        }
-    };
-}
-
-impl_is_zero!(i8, |x| x == 0); // It is needed to impl for arrays and tuples of i8.
-impl_is_zero!(i16, |x| x == 0);
-impl_is_zero!(i32, |x| x == 0);
-impl_is_zero!(i64, |x| x == 0);
-impl_is_zero!(i128, |x| x == 0);
-impl_is_zero!(isize, |x| x == 0);
-
-impl_is_zero!(u8, |x| x == 0); // It is needed to impl for arrays and tuples of u8.
-impl_is_zero!(u16, |x| x == 0);
-impl_is_zero!(u32, |x| x == 0);
-impl_is_zero!(u64, |x| x == 0);
-impl_is_zero!(u128, |x| x == 0);
-impl_is_zero!(usize, |x| x == 0);
-
-impl_is_zero!(bool, |x| x == false);
-impl_is_zero!(char, |x| x == '\0');
-
-impl_is_zero!(f32, |x: f32| x.to_bits() == 0);
-impl_is_zero!(f64, |x: f64| x.to_bits() == 0);
-
-unsafe impl<T> IsZero for *const T {
-    #[inline]
-    fn is_zero(&self) -> bool {
-        (*self).is_null()
-    }
-}
-
-unsafe impl<T> IsZero for *mut T {