From f4166487ff37e6fce9e5558f4aea5d8b034bcdc8 Mon Sep 17 00:00:00 2001
From: Carl Sverre <82591+carlsverre@users.noreply.github.com>
Date: Thu, 23 Jan 2025 08:51:21 -0800
Subject: [PATCH 1/2] Add memory layout documentation to generic NonZero<T>

---
 library/core/src/num/nonzero.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index dbce64420ac45..bf7ba3222d0e2 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -90,6 +90,26 @@ impl_zeroable_primitive!(
 ///
 /// assert_eq!(size_of::<Option<NonZero<u32>>>(), size_of::<u32>());
 /// ```
+///
+/// # Layout
+///
+/// `NonZero<T>` is guaranteed to have the same layout and bit validity as `T`
+/// with the exception that the all-zero bit pattern is not a valid instance.
+/// `Option<NonZero<T>>` is guaranteed to be compatible with `T`, including in
+/// FFI.
+///
+/// Thanks to the [null pointer optimization], `NonZero<T>` and
+/// `Option<NonZero<T>>` are guaranteed to have the same size and alignment:
+///
+/// ```
+/// # use std::mem::{size_of, align_of};
+/// use std::num::NonZero;
+///
+/// assert_eq!(size_of::<NonZero<u32>>(), size_of::<Option<NonZero<u32>>>());
+/// assert_eq!(align_of::<NonZero<u32>>(), align_of::<Option<NonZero<u32>>>());
+/// ```
+///
+/// [null pointer optimization]: crate::option#representation
 #[stable(feature = "generic_nonzero", since = "1.79.0")]
 #[repr(transparent)]
 #[rustc_nonnull_optimization_guaranteed]

From 4a8de9ac41d6010ef3f4e930894be3628ccc3fc6 Mon Sep 17 00:00:00 2001
From: Carl Sverre <82591+carlsverre@users.noreply.github.com>
Date: Fri, 24 Jan 2025 09:15:19 -0800
Subject: [PATCH 2/2] Update library/core/src/num/nonzero.rs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Tweak language

Co-authored-by: Jonas Böttiger <jonasboettiger@icloud.com>
---
 library/core/src/num/nonzero.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index bf7ba3222d0e2..8089d6164090d 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -94,7 +94,7 @@ impl_zeroable_primitive!(
 /// # Layout
 ///
 /// `NonZero<T>` is guaranteed to have the same layout and bit validity as `T`
-/// with the exception that the all-zero bit pattern is not a valid instance.
+/// with the exception that the all-zero bit pattern is invalid.
 /// `Option<NonZero<T>>` is guaranteed to be compatible with `T`, including in
 /// FFI.
 ///