From ac96fa44faa786ad5682e6ed7359842d0e6a4b53 Mon Sep 17 00:00:00 2001
From: Kevin Reid <kpreid@switchb.org>
Date: Sun, 12 May 2024 21:31:13 -0700
Subject: [PATCH 1/2] Use inline const instead of unsafe to construct arrays in
 `MaybeUninit` examples.

---
 library/core/src/mem/maybe_uninit.rs | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/library/core/src/mem/maybe_uninit.rs b/library/core/src/mem/maybe_uninit.rs
index 026e21586d403..56af7fa9c89c2 100644
--- a/library/core/src/mem/maybe_uninit.rs
+++ b/library/core/src/mem/maybe_uninit.rs
@@ -120,12 +120,8 @@ use crate::slice;
 /// use std::mem::{self, MaybeUninit};
 ///
 /// let data = {
-///     // Create an uninitialized array of `MaybeUninit`. The `assume_init` is
-///     // safe because the type we are claiming to have initialized here is a
-///     // bunch of `MaybeUninit`s, which do not require initialization.
-///     let mut data: [MaybeUninit<Vec<u32>>; 1000] = unsafe {
-///         MaybeUninit::uninit().assume_init()
-///     };
+///     // Create an uninitialized array of `MaybeUninit`.
+///     let mut data: [MaybeUninit<Vec<u32>>; 1000] = [const { MaybeUninit::uninit() }; 1000];
 ///
 ///     // Dropping a `MaybeUninit` does nothing, so if there is a panic during this loop,
 ///     // we have a memory leak, but there is no memory safety issue.
@@ -147,10 +143,8 @@ use crate::slice;
 /// ```
 /// use std::mem::MaybeUninit;
 ///
-/// // Create an uninitialized array of `MaybeUninit`. The `assume_init` is
-/// // safe because the type we are claiming to have initialized here is a
-/// // bunch of `MaybeUninit`s, which do not require initialization.
-/// let mut data: [MaybeUninit<String>; 1000] = unsafe { MaybeUninit::uninit().assume_init() };
+/// // Create an uninitialized array of `MaybeUninit`.
+/// let mut data: [MaybeUninit<String>; 1000] = [const { MaybeUninit::uninit() }; 1000];
 /// // Count the number of elements we have assigned.
 /// let mut data_len: usize = 0;
 ///

From ec8fa177190f1f0279fade487dfa4cef23dd1101 Mon Sep 17 00:00:00 2001
From: Kevin Reid <kpreid@switchb.org>
Date: Sun, 12 May 2024 21:36:09 -0700
Subject: [PATCH 2/2] Use inline const instead of unsafe to implement
 `MaybeUninit::uninit_array()`.

---
 library/core/src/mem/maybe_uninit.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/library/core/src/mem/maybe_uninit.rs b/library/core/src/mem/maybe_uninit.rs
index 56af7fa9c89c2..4175d4a33294b 100644
--- a/library/core/src/mem/maybe_uninit.rs
+++ b/library/core/src/mem/maybe_uninit.rs
@@ -342,8 +342,7 @@ impl<T> MaybeUninit<T> {
     #[must_use]
     #[inline(always)]
     pub const fn uninit_array<const N: usize>() -> [Self; N] {
-        // SAFETY: An uninitialized `[MaybeUninit<_>; LEN]` is valid.
-        unsafe { MaybeUninit::<[MaybeUninit<T>; N]>::uninit().assume_init() }
+        [const { MaybeUninit::uninit() }; N]
     }
 
     /// Creates a new `MaybeUninit<T>` in an uninitialized state, with the memory being