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-rw-r--r--src/libcore/cmp.rs6
-rw-r--r--src/libcore/convert.rs24
-rw-r--r--src/libcore/fmt/mod.rs3
-rw-r--r--src/libcore/hint.rs16
-rw-r--r--src/libcore/iter/adapters/mod.rs4
-rw-r--r--src/libcore/macros.rs8
-rw-r--r--src/libcore/num/f32.rs2
-rw-r--r--src/libcore/num/f64.rs2
-rw-r--r--src/libcore/ops/function.rs8
-rw-r--r--src/libcore/slice/mod.rs3
-rw-r--r--src/libcore/str/mod.rs9
11 files changed, 41 insertions, 44 deletions
diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs
index cb9feb074dd..607427a85d6 100644
--- a/src/libcore/cmp.rs
+++ b/src/libcore/cmp.rs
@@ -1012,8 +1012,10 @@ mod impls {
             impl Ord for $t {
                 #[inline]
                 fn cmp(&self, other: &$t) -> Ordering {
-                    if *self == *other { Equal }
-                    else if *self < *other { Less }
+                    // The order here is important to generate more optimal assembly.
+                    // See <https://github.com/rust-lang/rust/issues/63758> for more info.
+                    if *self < *other { Less }
+                    else if *self == *other { Equal }
                     else { Greater }
                 }
             }
diff --git a/src/libcore/convert.rs b/src/libcore/convert.rs
index 641621f492b..402a7b2c95a 100644
--- a/src/libcore/convert.rs
+++ b/src/libcore/convert.rs
@@ -104,22 +104,17 @@ pub const fn identity<T>(x: T) -> T { x }
 /// If you need to do a costly conversion it is better to implement [`From`] with type
 /// `&T` or write a custom function.
 ///
-/// `AsRef` has the same signature as [`Borrow`], but `Borrow` is different in few aspects:
+/// `AsRef` has the same signature as [`Borrow`], but [`Borrow`] is different in few aspects:
 ///
-/// - Unlike `AsRef`, `Borrow` has a blanket impl for any `T`, and can be used to accept either
+/// - Unlike `AsRef`, [`Borrow`] has a blanket impl for any `T`, and can be used to accept either
 ///   a reference or a value.
-/// - `Borrow` also requires that `Hash`, `Eq` and `Ord` for borrowed value are
+/// - [`Borrow`] also requires that [`Hash`], [`Eq`] and [`Ord`] for borrowed value are
 ///   equivalent to those of the owned value. For this reason, if you want to
-///   borrow only a single field of a struct you can implement `AsRef`, but not `Borrow`.
-///
-/// [`Borrow`]: ../../std/borrow/trait.Borrow.html
+///   borrow only a single field of a struct you can implement `AsRef`, but not [`Borrow`].
 ///
 /// **Note: This trait must not fail**. If the conversion can fail, use a
 /// dedicated method which returns an [`Option<T>`] or a [`Result<T, E>`].
 ///
-/// [`Option<T>`]: ../../std/option/enum.Option.html
-/// [`Result<T, E>`]: ../../std/result/enum.Result.html
-///
 /// # Generic Implementations
 ///
 /// - `AsRef` auto-dereferences if the inner type is a reference or a mutable
@@ -132,9 +127,16 @@ pub const fn identity<T>(x: T) -> T { x }
 /// converted to the specified type `T`.
 ///
 /// For example: By creating a generic function that takes an `AsRef<str>` we express that we
-/// want to accept all references that can be converted to `&str` as an argument.
-/// Since both [`String`] and `&str` implement `AsRef<str>` we can accept both as input argument.
+/// want to accept all references that can be converted to [`&str`] as an argument.
+/// Since both [`String`] and [`&str`] implement `AsRef<str>` we can accept both as input argument.
 ///
+/// [`Option<T>`]: ../../std/option/enum.Option.html
+/// [`Result<T, E>`]: ../../std/result/enum.Result.html
+/// [`Borrow`]: ../../std/borrow/trait.Borrow.html
+/// [`Hash`]: ../../std/hash/trait.Hash.html
+/// [`Eq`]: ../../std/cmp/trait.Eq.html
+/// [`Ord`]: ../../std/cmp/trait.Ord.html
+/// [`&str`]: ../../std/primitive.str.html
 /// [`String`]: ../../std/string/struct.String.html
 ///
 /// ```
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index bd31d25dd03..7e35188bc10 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -518,7 +518,8 @@ impl Display for Arguments<'_> {
     label="`{Self}` cannot be formatted using `{{:?}}` because it doesn't implement `{Debug}`",
 )]
 #[doc(alias = "{:?}")]
-#[lang = "debug_trait"]
+#[cfg_attr(boostrap_stdarch_ignore_this, lang = "debug_trait")]
+#[cfg_attr(not(boostrap_stdarch_ignore_this), rustc_diagnostic_item = "debug_trait")]
 pub trait Debug {
     /// Formats the value using the given formatter.
     ///
diff --git a/src/libcore/hint.rs b/src/libcore/hint.rs
index 3b2b28217f9..6439fa0e0c8 100644
--- a/src/libcore/hint.rs
+++ b/src/libcore/hint.rs
@@ -104,11 +104,19 @@ pub fn spin_loop() {
     }
 }
 
-/// A function that is opaque to the optimizer, to allow benchmarks to
-/// pretend to use outputs to assist in avoiding dead-code
-/// elimination.
+/// An identity function that *__hints__* to the compiler to be maximally pessimistic about what
+/// `black_box` could do.
 ///
-/// This function is a no-op, and does not even read from `dummy`.
+/// [`std::convert::identity`]: https://doc.rust-lang.org/core/convert/fn.identity.html
+///
+/// Unlike [`std::convert::identity`], a Rust compiler is encouraged to assume that `black_box` can
+/// use `x` in any possible valid way that Rust code is allowed to without introducing undefined
+/// behavior in the calling code. This property makes `black_box` useful for writing code in which
+/// certain optimizations are not desired, such as benchmarks.
+///
+/// Note however, that `black_box` is only (and can only be) provided on a "best-effort" basis. The
+/// extent to which it can block optimisations may vary depending upon the platform and code-gen
+/// backend used. Programs cannot rely on `black_box` for *correctness* in any way.
 #[inline]
 #[unstable(feature = "test", issue = "50297")]
 #[allow(unreachable_code)] // this makes #[cfg] a bit easier below.
diff --git a/src/libcore/iter/adapters/mod.rs b/src/libcore/iter/adapters/mod.rs
index a63434abd6c..f50781890ab 100644
--- a/src/libcore/iter/adapters/mod.rs
+++ b/src/libcore/iter/adapters/mod.rs
@@ -1309,7 +1309,7 @@ impl<I> DoubleEndedIterator for Peekable<I> where I: DoubleEndedIterator {
         Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
     {
         match self.peeked.take() {
-            Some(None) => return Try::from_ok(init),
+            Some(None) => Try::from_ok(init),
             Some(Some(v)) => match self.iter.try_rfold(init, &mut f).into_result() {
                 Ok(acc) => f(acc, v),
                 Err(e) => {
@@ -1326,7 +1326,7 @@ impl<I> DoubleEndedIterator for Peekable<I> where I: DoubleEndedIterator {
         where Fold: FnMut(Acc, Self::Item) -> Acc,
     {
         match self.peeked {
-            Some(None) => return init,
+            Some(None) => init,
             Some(Some(v)) => {
                 let acc = self.iter.rfold(init, &mut fold);
                 fold(acc, v)
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index 6c88a766a2f..ffaca029a8a 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -734,7 +734,6 @@ pub(crate) mod builtin {
     #[allow_internal_unstable(fmt_internals)]
     #[rustc_builtin_macro]
     #[macro_export]
-    #[rustc_macro_transparency = "opaque"]
     macro_rules! format_args {
         ($fmt:expr) => ({ /* compiler built-in */ });
         ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ })
@@ -747,7 +746,6 @@ pub(crate) mod builtin {
     #[allow_internal_unstable(fmt_internals)]
     #[rustc_builtin_macro]
     #[macro_export]
-    #[rustc_macro_transparency = "opaque"]
     macro_rules! format_args_nl {
         ($fmt:expr) => ({ /* compiler built-in */ });
         ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ })
@@ -1235,7 +1233,6 @@ pub(crate) mod builtin {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro test($item:item) { /* compiler built-in */ }
 
     /// Attribute macro applied to a function to turn it into a benchmark test.
@@ -1243,7 +1240,6 @@ pub(crate) mod builtin {
                reason = "`bench` is a part of custom test frameworks which are unstable")]
     #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro bench($item:item) { /* compiler built-in */ }
 
     /// An implementation detail of the `#[test]` and `#[bench]` macros.
@@ -1251,26 +1247,22 @@ pub(crate) mod builtin {
                reason = "custom test frameworks are an unstable feature")]
     #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro test_case($item:item) { /* compiler built-in */ }
 
     /// Attribute macro applied to a static to register it as a global allocator.
     #[stable(feature = "global_allocator", since = "1.28.0")]
     #[allow_internal_unstable(rustc_attrs)]
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
     pub macro global_allocator($item:item) { /* compiler built-in */ }
 
     /// Unstable implementation detail of the `rustc` compiler, do not use.
     #[rustc_builtin_macro]
-    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(core_intrinsics, libstd_sys_internals)]
     pub macro RustcDecodable($item:item) { /* compiler built-in */ }
 
     /// Unstable implementation detail of the `rustc` compiler, do not use.
     #[rustc_builtin_macro]
-    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(core_intrinsics)]
     pub macro RustcEncodable($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/num/f32.rs b/src/libcore/num/f32.rs
index 8ff78166a9f..22e7573eca6 100644
--- a/src/libcore/num/f32.rs
+++ b/src/libcore/num/f32.rs
@@ -315,7 +315,7 @@ impl f32 {
     /// use std::f32;
     ///
     /// let x = 2.0_f32;
-    /// let abs_difference = (x.recip() - (1.0/x)).abs();
+    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
     ///
     /// assert!(abs_difference <= f32::EPSILON);
     /// ```
diff --git a/src/libcore/num/f64.rs b/src/libcore/num/f64.rs
index d45c04f45af..bbe1d040780 100644
--- a/src/libcore/num/f64.rs
+++ b/src/libcore/num/f64.rs
@@ -327,7 +327,7 @@ impl f64 {
     ///
     /// ```
     /// let x = 2.0_f64;
-    /// let abs_difference = (x.recip() - (1.0/x)).abs();
+    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
     ///
     /// assert!(abs_difference < 1e-10);
     /// ```
diff --git a/src/libcore/ops/function.rs b/src/libcore/ops/function.rs
index b9552eaa1a0..4a0a2720fe4 100644
--- a/src/libcore/ops/function.rs
+++ b/src/libcore/ops/function.rs
@@ -185,14 +185,6 @@ pub trait FnMut<Args> : FnOnce<Args> {
 ///
 /// # Examples
 ///
-/// ## Calling a by-value closure
-///
-/// ```
-/// let x = 5;
-/// let square_x = move || x * x;
-/// assert_eq!(square_x(), 25);
-/// ```
-///
 /// ## Using a `FnOnce` parameter
 ///
 /// ```
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index bfbbb15c8d4..931768564ca 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -3026,8 +3026,7 @@ macro_rules! len {
         if size == 0 {
             // This _cannot_ use `unchecked_sub` because we depend on wrapping
             // to represent the length of long ZST slice iterators.
-            let diff = ($self.end as usize).wrapping_sub(start as usize);
-            diff
+            ($self.end as usize).wrapping_sub(start as usize)
         } else {
             // We know that `start <= end`, so can do better than `offset_from`,
             // which needs to deal in signed.  By setting appropriate flags here
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index f20cb7bfbc3..5e5b5593fd8 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -2170,6 +2170,7 @@ impl str {
     #[inline(always)]
     #[rustc_const_unstable(feature="const_str_as_bytes")]
     pub const fn as_bytes(&self) -> &[u8] {
+        #[repr(C)]
         union Slices<'a> {
             str: &'a str,
             slice: &'a [u8],
@@ -3557,7 +3558,7 @@ impl str {
     /// A string is a sequence of bytes. `start` in this context means the first
     /// position of that byte string; for a left-to-right language like English or
     /// Russian, this will be left side, and for right-to-left languages like
-    /// like Arabic or Hebrew, this will be the right side.
+    /// Arabic or Hebrew, this will be the right side.
     ///
     /// # Examples
     ///
@@ -3594,7 +3595,7 @@ impl str {
     /// A string is a sequence of bytes. `end` in this context means the last
     /// position of that byte string; for a left-to-right language like English or
     /// Russian, this will be right side, and for right-to-left languages like
-    /// like Arabic or Hebrew, this will be the left side.
+    /// Arabic or Hebrew, this will be the left side.
     ///
     /// # Examples
     ///
@@ -3761,7 +3762,7 @@ impl str {
     /// A string is a sequence of bytes. `start` in this context means the first
     /// position of that byte string; for a left-to-right language like English or
     /// Russian, this will be left side, and for right-to-left languages like
-    /// like Arabic or Hebrew, this will be the right side.
+    /// Arabic or Hebrew, this will be the right side.
     ///
     /// # Examples
     ///
@@ -3800,7 +3801,7 @@ impl str {
     /// A string is a sequence of bytes. `end` in this context means the last
     /// position of that byte string; for a left-to-right language like English or
     /// Russian, this will be right side, and for right-to-left languages like
-    /// like Arabic or Hebrew, this will be the left side.
+    /// Arabic or Hebrew, this will be the left side.
     ///
     /// # Examples
     ///
generated by cgit-pink 1.4.1-3-g733a5 (git 2.37.1) at 2025-11-01 16:53:59 +0000