Auto merge of #87689 - JohnTitor:rollup-ns38b56, r=JohnTitor

Rollup of 13 pull requests

Successful merges:

 - #86183 (Change environment variable getters to error recoverably)
 - #86439 (Remove `Ipv4Addr::is_ietf_protocol_assignment`)
 - #86509 (Move `os_str_bytes` to `sys::unix`)
 - #86593 (Partially stabilize `const_slice_first_last`)
 - #86936 (Add documentation for `Ipv6MulticastScope`)
 - #87282 (Ensure `./x.py dist` adheres to `build.tools`)
 - #87468 (Update rustfmt)
 - #87504 (Update mdbook.)
 - #87608 (Remove unused field `Session.system_library_path`)
 - #87629 (Consistent spelling of "adapter" in the standard library)
 - #87633 (Update compiler_builtins to fix i128 shift/mul on thumbv6m)
 - #87644 (Recommend `swap_remove` in `Vec::remove` docs)
 - #87653 (mark a UB doctest as no_run)

Failed merges:

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

4 files changed, 16 insertions, 10 deletions

diff --git a/library/core/src/alloc/mod.rs b/library/core/src/alloc/mod.rs
index 06a761531b6..1f1033b0437 100644
--- a/library/core/src/alloc/mod.rs
+++ b/library/core/src/alloc/mod.rs
@@ -338,9 +338,9 @@ pub unsafe trait Allocator {
         Ok(new_ptr)
     }
 
-    /// Creates a "by reference" adaptor for this instance of `Allocator`.
+    /// Creates a "by reference" adapter for this instance of `Allocator`.
     ///
-    /// The returned adaptor also implements `Allocator` and will simply borrow this.
+    /// The returned adapter also implements `Allocator` and will simply borrow this.
     #[inline(always)]
     fn by_ref(&self) -> &Self
     where
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index f34adb878c4..537e42f66de 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -694,7 +694,7 @@ pub trait Iterator {
     /// more idiomatic to use a `for` loop, but `for_each` may be more legible
     /// when processing items at the end of longer iterator chains. In some
     /// cases `for_each` may also be faster than a loop, because it will use
-    /// internal iteration on adaptors like `Chain`.
+    /// internal iteration on adapters like `Chain`.
     ///
     /// [`for`]: ../../book/ch03-05-control-flow.html#looping-through-a-collection-with-for
     ///
@@ -1293,7 +1293,7 @@ pub trait Iterator {
         Take::new(self, n)
     }
 
-    /// An iterator adaptor similar to [`fold`] that holds internal state and
+    /// An iterator adapter similar to [`fold`] that holds internal state and
     /// produces a new iterator.
     ///
     /// [`fold`]: Iterator::fold
@@ -1604,7 +1604,7 @@ pub trait Iterator {
 
     /// Borrows an iterator, rather than consuming it.
     ///
-    /// This is useful to allow applying iterator adaptors while still
+    /// This is useful to allow applying iterator adapters while still
     /// retaining ownership of the original iterator.
     ///
     /// # Examples
diff --git a/library/core/src/ptr/non_null.rs b/library/core/src/ptr/non_null.rs
index 032df7f5a80..87c8674af0d 100644
--- a/library/core/src/ptr/non_null.rs
+++ b/library/core/src/ptr/non_null.rs
@@ -173,8 +173,14 @@ impl<T: ?Sized> NonNull<T> {
     ///
     /// let mut x = 0u32;
     /// let ptr = unsafe { NonNull::new_unchecked(&mut x as *mut _) };
+    /// ```
+    ///
+    /// *Incorrect* usage of this function:
+    ///
+    /// ```rust,no_run
+    /// use std::ptr::NonNull;
     ///
-    /// // NEVER DO THAT!!!
+    /// // NEVER DO THAT!!! This is undefined behavior. ⚠️
     /// let ptr = unsafe { NonNull::<u32>::new_unchecked(std::ptr::null_mut()) };
     /// ```
     #[stable(feature = "nonnull", since = "1.25.0")]
diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index 261b9a3feb7..67eecab99d8 100644
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -139,7 +139,7 @@ impl<T> [T] {
     /// assert_eq!(None, w.first());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn first(&self) -> Option<&T> {
         if let [first, ..] = self { Some(first) } else { None }
@@ -177,7 +177,7 @@ impl<T> [T] {
     /// }
     /// ```
     #[stable(feature = "slice_splits", since = "1.5.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn split_first(&self) -> Option<(&T, &[T])> {
         if let [first, tail @ ..] = self { Some((first, tail)) } else { None }
@@ -217,7 +217,7 @@ impl<T> [T] {
     /// }
     /// ```
     #[stable(feature = "slice_splits", since = "1.5.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn split_last(&self) -> Option<(&T, &[T])> {
         if let [init @ .., last] = self { Some((last, init)) } else { None }
@@ -256,7 +256,7 @@ impl<T> [T] {
     /// assert_eq!(None, w.last());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn last(&self) -> Option<&T> {
         if let [.., last] = self { Some(last) } else { None }