Merge pull request #20761 from rust-lang/rustc-pull

Rustc pull update

31 files changed, 287 insertions, 163 deletions

diff --git a/library/core/src/any.rs b/library/core/src/any.rs
index 76ea2d18a82..3ab95438c3f 100644
--- a/library/core/src/any.rs
+++ b/library/core/src/any.rs
@@ -774,7 +774,7 @@ impl TypeId {
     /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_stable(feature = "const_type_id", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "const_type_id", since = "1.91.0")]
     pub const fn of<T: ?Sized + 'static>() -> TypeId {
         const { intrinsics::type_id::<T>() }
     }
diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index d713e575b58..0dc10758a85 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -49,7 +49,7 @@ pub use iter::IntoIter;
 /// ```
 #[inline]
 #[must_use = "cloning is often expensive and is not expected to have side effects"]
-#[stable(feature = "array_repeat", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "array_repeat", since = "1.91.0")]
 pub fn repeat<T: Clone, const N: usize>(val: T) -> [T; N] {
     from_trusted_iterator(repeat_n(val, N))
 }
@@ -627,7 +627,7 @@ impl<T, const N: usize> [T; N] {
     /// assert_eq!(strings.len(), 3);
     /// ```
     #[stable(feature = "array_methods", since = "1.77.0")]
-    #[rustc_const_stable(feature = "const_array_each_ref", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "const_array_each_ref", since = "1.91.0")]
     pub const fn each_ref(&self) -> [&T; N] {
         let mut buf = [null::<T>(); N];
 
@@ -658,7 +658,7 @@ impl<T, const N: usize> [T; N] {
     /// assert_eq!(floats, [0.0, 2.7, -1.0]);
     /// ```
     #[stable(feature = "array_methods", since = "1.77.0")]
-    #[rustc_const_stable(feature = "const_array_each_ref", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "const_array_each_ref", since = "1.91.0")]
     pub const fn each_mut(&mut self) -> [&mut T; N] {
         let mut buf = [null_mut::<T>(); N];
 
diff --git a/library/core/src/cell.rs b/library/core/src/cell.rs
index 7d4a66640b1..6aadb7a86cd 100644
--- a/library/core/src/cell.rs
+++ b/library/core/src/cell.rs
@@ -705,8 +705,8 @@ impl<T, const N: usize> Cell<[T; N]> {
     /// let cell_array: &Cell<[i32; 3]> = Cell::from_mut(&mut array);
     /// let array_cell: &[Cell<i32>; 3] = cell_array.as_array_of_cells();
     /// ```
-    #[stable(feature = "as_array_of_cells", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "as_array_of_cells", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "as_array_of_cells", since = "1.91.0")]
+    #[rustc_const_stable(feature = "as_array_of_cells", since = "1.91.0")]
     pub const fn as_array_of_cells(&self) -> &[Cell<T>; N] {
         // SAFETY: `Cell<T>` has the same memory layout as `T`.
         unsafe { &*(self as *const Cell<[T; N]> as *const [Cell<T>; N]) }
diff --git a/library/core/src/error.rs b/library/core/src/error.rs
index 92b3c83d1bf..9ca91ee009e 100644
--- a/library/core/src/error.rs
+++ b/library/core/src/error.rs
@@ -16,13 +16,19 @@ use crate::fmt::{self, Debug, Display, Formatter};
 /// assert_eq!(err.to_string(), "invalid digit found in string");
 /// ```
 ///
+/// # Error source
+///
 /// Errors may provide cause information. [`Error::source()`] is generally
 /// used when errors cross "abstraction boundaries". If one module must report
 /// an error that is caused by an error from a lower-level module, it can allow
-/// accessing that error via [`Error::source()`]. This makes it possible for the
+/// accessing that error via `Error::source()`. This makes it possible for the
 /// high-level module to provide its own errors while also revealing some of the
 /// implementation for debugging.
 ///
+/// In error types that wrap an underlying error, the underlying error
+/// should be either returned by the outer error's `Error::source()`, or rendered
+/// by the outer error's `Display` implementation, but not both.
+///
 /// # Example
 ///
 /// Implementing the `Error` trait only requires that `Debug` and `Display` are implemented too.
diff --git a/library/core/src/ffi/c_str.rs b/library/core/src/ffi/c_str.rs
index d0b53e3a237..09d9b160700 100644
--- a/library/core/src/ffi/c_str.rs
+++ b/library/core/src/ffi/c_str.rs
@@ -179,9 +179,7 @@ impl fmt::Debug for CStr {
 impl Default for &CStr {
     #[inline]
     fn default() -> Self {
-        const SLICE: &[c_char] = &[0];
-        // SAFETY: `SLICE` is indeed pointing to a valid nul-terminated string.
-        unsafe { CStr::from_ptr(SLICE.as_ptr()) }
+        c""
     }
 }
 
diff --git a/library/core/src/ffi/mod.rs b/library/core/src/ffi/mod.rs
index 0bc98e2ea86..1356ca217c9 100644
--- a/library/core/src/ffi/mod.rs
+++ b/library/core/src/ffi/mod.rs
@@ -56,7 +56,7 @@ pub use self::primitives::{c_ptrdiff_t, c_size_t, c_ssize_t};
 //     be UB.
 #[doc = include_str!("c_void.md")]
 #[lang = "c_void"]
-#[cfg_attr(not(doc), repr(u8))] // An implementation detail we don't want to show up in rustdoc
+#[repr(u8)]
 #[stable(feature = "core_c_void", since = "1.30.0")]
 pub enum c_void {
     #[unstable(
diff --git a/library/core/src/ffi/va_list.rs b/library/core/src/ffi/va_list.rs
index 0d4ccb5aeb2..46ccf330d1c 100644
--- a/library/core/src/ffi/va_list.rs
+++ b/library/core/src/ffi/va_list.rs
@@ -25,7 +25,7 @@ crate::cfg_select! {
         ///
         /// [AArch64 Procedure Call Standard]:
         /// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0055b/IHI0055B_aapcs64.pdf
-        #[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
+        #[repr(C)]
         #[derive(Debug)]
         #[lang = "va_list"]
         pub struct VaListImpl<'f> {
@@ -39,7 +39,7 @@ crate::cfg_select! {
     }
     all(target_arch = "powerpc", not(target_os = "uefi"), not(windows)) => {
         /// PowerPC ABI implementation of a `va_list`.
-        #[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
+        #[repr(C)]
         #[derive(Debug)]
         #[lang = "va_list"]
         pub struct VaListImpl<'f> {
@@ -53,7 +53,7 @@ crate::cfg_select! {
     }
     target_arch = "s390x" => {
         /// s390x ABI implementation of a `va_list`.
-        #[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
+        #[repr(C)]
         #[derive(Debug)]
         #[lang = "va_list"]
         pub struct VaListImpl<'f> {
@@ -66,7 +66,7 @@ crate::cfg_select! {
     }
     all(target_arch = "x86_64", not(target_os = "uefi"), not(windows)) => {
         /// x86_64 ABI implementation of a `va_list`.
-        #[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
+        #[repr(C)]
         #[derive(Debug)]
         #[lang = "va_list"]
         pub struct VaListImpl<'f> {
diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index b6de8925308..fcd2e52101f 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -386,8 +386,8 @@ impl FormattingOptions {
     /// used. The alternate forms are:
     /// - [`Debug`] : pretty-print the [`Debug`] formatting (adds linebreaks and indentation)
     /// - [`LowerHex`] as well as [`UpperHex`] - precedes the argument with a `0x`
-    /// - [`Octal`] - precedes the argument with a `0b`
-    /// - [`Binary`] - precedes the argument with a `0o`
+    /// - [`Octal`] - precedes the argument with a `0o`
+    /// - [`Binary`] - precedes the argument with a `0b`
     #[unstable(feature = "formatting_options", issue = "118117")]
     pub const fn alternate(&mut self, alternate: bool) -> &mut Self {
         if alternate {
diff --git a/library/core/src/intrinsics/mod.rs b/library/core/src/intrinsics/mod.rs
index eaf2738d8b7..cef700be9ea 100644
--- a/library/core/src/intrinsics/mod.rs
+++ b/library/core/src/intrinsics/mod.rs
@@ -1312,28 +1312,28 @@ pub fn log2f128(x: f128) -> f128;
 /// [`f16::mul_add`](../../std/primitive.f16.html#method.mul_add)
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmaf16(a: f16, b: f16, c: f16) -> f16;
+pub const fn fmaf16(a: f16, b: f16, c: f16) -> f16;
 /// Returns `a * b + c` for `f32` values.
 ///
 /// The stabilized version of this intrinsic is
 /// [`f32::mul_add`](../../std/primitive.f32.html#method.mul_add)
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmaf32(a: f32, b: f32, c: f32) -> f32;
+pub const fn fmaf32(a: f32, b: f32, c: f32) -> f32;
 /// Returns `a * b + c` for `f64` values.
 ///
 /// The stabilized version of this intrinsic is
 /// [`f64::mul_add`](../../std/primitive.f64.html#method.mul_add)
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmaf64(a: f64, b: f64, c: f64) -> f64;
+pub const fn fmaf64(a: f64, b: f64, c: f64) -> f64;
 /// Returns `a * b + c` for `f128` values.
 ///
 /// The stabilized version of this intrinsic is
 /// [`f128::mul_add`](../../std/primitive.f128.html#method.mul_add)
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmaf128(a: f128, b: f128, c: f128) -> f128;
+pub const fn fmaf128(a: f128, b: f128, c: f128) -> f128;
 
 /// Returns `a * b + c` for `f16` values, non-deterministically executing
 /// either a fused multiply-add or two operations with rounding of the
@@ -1347,7 +1347,7 @@ pub fn fmaf128(a: f128, b: f128, c: f128) -> f128;
 /// example.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmuladdf16(a: f16, b: f16, c: f16) -> f16;
+pub const fn fmuladdf16(a: f16, b: f16, c: f16) -> f16;
 /// Returns `a * b + c` for `f32` values, non-deterministically executing
 /// either a fused multiply-add or two operations with rounding of the
 /// intermediate result.
@@ -1360,7 +1360,7 @@ pub fn fmuladdf16(a: f16, b: f16, c: f16) -> f16;
 /// example.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmuladdf32(a: f32, b: f32, c: f32) -> f32;
+pub const fn fmuladdf32(a: f32, b: f32, c: f32) -> f32;
 /// Returns `a * b + c` for `f64` values, non-deterministically executing
 /// either a fused multiply-add or two operations with rounding of the
 /// intermediate result.
@@ -1373,7 +1373,7 @@ pub fn fmuladdf32(a: f32, b: f32, c: f32) -> f32;
 /// example.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmuladdf64(a: f64, b: f64, c: f64) -> f64;
+pub const fn fmuladdf64(a: f64, b: f64, c: f64) -> f64;
 /// Returns `a * b + c` for `f128` values, non-deterministically executing
 /// either a fused multiply-add or two operations with rounding of the
 /// intermediate result.
@@ -1386,7 +1386,7 @@ pub fn fmuladdf64(a: f64, b: f64, c: f64) -> f64;
 /// example.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub fn fmuladdf128(a: f128, b: f128, c: f128) -> f128;
+pub const fn fmuladdf128(a: f128, b: f128, c: f128) -> f128;
 
 /// Returns the largest integer less than or equal to an `f16`.
 ///
diff --git a/library/core/src/iter/adapters/chain.rs b/library/core/src/iter/adapters/chain.rs
index 3ebdf7b4727..0ece54554d4 100644
--- a/library/core/src/iter/adapters/chain.rs
+++ b/library/core/src/iter/adapters/chain.rs
@@ -60,7 +60,7 @@ impl<A, B> Chain<A, B> {
 /// assert_eq!(iter.next(), Some(6));
 /// assert_eq!(iter.next(), None);
 /// ```
-#[stable(feature = "iter_chain", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "iter_chain", since = "1.91.0")]
 pub fn chain<A, B>(a: A, b: B) -> Chain<A::IntoIter, B::IntoIter>
 where
     A: IntoIterator,
diff --git a/library/core/src/iter/adapters/mod.rs b/library/core/src/iter/adapters/mod.rs
index 6c6de0a4e5c..1ff5093922b 100644
--- a/library/core/src/iter/adapters/mod.rs
+++ b/library/core/src/iter/adapters/mod.rs
@@ -32,7 +32,7 @@ mod zip;
 pub use self::array_chunks::ArrayChunks;
 #[unstable(feature = "std_internals", issue = "none")]
 pub use self::by_ref_sized::ByRefSized;
-#[stable(feature = "iter_chain", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "iter_chain", since = "1.91.0")]
 pub use self::chain::chain;
 #[stable(feature = "iter_cloned", since = "1.1.0")]
 pub use self::cloned::Cloned;
diff --git a/library/core/src/iter/mod.rs b/library/core/src/iter/mod.rs
index bc07324f520..c7e1c4ef767 100644
--- a/library/core/src/iter/mod.rs
+++ b/library/core/src/iter/mod.rs
@@ -404,7 +404,7 @@ pub use self::adapters::StepBy;
 pub use self::adapters::TrustedRandomAccess;
 #[unstable(feature = "trusted_random_access", issue = "none")]
 pub use self::adapters::TrustedRandomAccessNoCoerce;
-#[stable(feature = "iter_chain", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "iter_chain", since = "1.91.0")]
 pub use self::adapters::chain;
 pub(crate) use self::adapters::try_process;
 #[stable(feature = "iter_zip", since = "1.59.0")]
diff --git a/library/core/src/iter/traits/accum.rs b/library/core/src/iter/traits/accum.rs
index 3b805139ded..375b5ef5285 100644
--- a/library/core/src/iter/traits/accum.rs
+++ b/library/core/src/iter/traits/accum.rs
@@ -148,7 +148,7 @@ macro_rules! saturating_integer_sum_product {
         saturating_integer_sum_product!(@impls Saturating(0), Saturating(1),
                 "The short-circuiting behavior of this implementation is unspecified. If you care about \
                 short-circuiting, use [`Iterator::fold`] directly.",
-                #[stable(feature = "saturating_iter_arith", since = "CURRENT_RUSTC_VERSION")],
+                #[stable(feature = "saturating_iter_arith", since = "1.91.0")],
                 $(Saturating<$a>)*);
     );
 }
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 5d52bfb1b12..54adf97f100 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -51,7 +51,7 @@
     test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
 )]
 #![doc(rust_logo)]
-#![doc(cfg_hide(
+#![doc(auto_cfg(hide(
     no_fp_fmt_parse,
     target_pointer_width = "16",
     target_pointer_width = "32",
@@ -71,7 +71,7 @@
     target_has_atomic_load_store = "32",
     target_has_atomic_load_store = "64",
     target_has_atomic_load_store = "ptr",
-))]
+)))]
 #![no_core]
 #![rustc_coherence_is_core]
 #![rustc_preserve_ub_checks]
@@ -149,7 +149,6 @@
 #![feature(deprecated_suggestion)]
 #![feature(derive_const)]
 #![feature(doc_cfg)]
-#![feature(doc_cfg_hide)]
 #![feature(doc_notable_trait)]
 #![feature(extern_types)]
 #![feature(f16)]
diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs
index 1c100312a9a..4b767d8d622 100644
--- a/library/core/src/marker.rs
+++ b/library/core/src/marker.rs
@@ -1341,11 +1341,3 @@ pub macro CoercePointee($item:item) {
 pub trait CoercePointeeValidated {
     /* compiler built-in */
 }
-
-/// Allows value to be reborrowed as exclusive, creating a copy of the value
-/// that disables the source for reads and writes for the lifetime of the copy.
-#[lang = "reborrow"]
-#[unstable(feature = "reborrow", issue = "145612")]
-pub trait Reborrow {
-    // Empty.
-}
diff --git a/library/core/src/net/ip_addr.rs b/library/core/src/net/ip_addr.rs
index 9779fb8fe4d..a1bfd774710 100644
--- a/library/core/src/net/ip_addr.rs
+++ b/library/core/src/net/ip_addr.rs
@@ -631,8 +631,8 @@ impl Ipv4Addr {
     /// let addr = Ipv4Addr::from_octets([13u8, 12u8, 11u8, 10u8]);
     /// assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);
     /// ```
-    #[stable(feature = "ip_from", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "ip_from", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "ip_from", since = "1.91.0")]
+    #[rustc_const_stable(feature = "ip_from", since = "1.91.0")]
     #[must_use]
     #[inline]
     pub const fn from_octets(octets: [u8; 4]) -> Ipv4Addr {
@@ -1478,8 +1478,8 @@ impl Ipv6Addr {
     ///     addr
     /// );
     /// ```
-    #[stable(feature = "ip_from", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "ip_from", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "ip_from", since = "1.91.0")]
+    #[rustc_const_stable(feature = "ip_from", since = "1.91.0")]
     #[must_use]
     #[inline]
     pub const fn from_segments(segments: [u16; 8]) -> Ipv6Addr {
@@ -2043,8 +2043,8 @@ impl Ipv6Addr {
     ///     addr
     /// );
     /// ```
-    #[stable(feature = "ip_from", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "ip_from", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "ip_from", since = "1.91.0")]
+    #[rustc_const_stable(feature = "ip_from", since = "1.91.0")]
     #[must_use]
     #[inline]
     pub const fn from_octets(octets: [u8; 16]) -> Ipv6Addr {
diff --git a/library/core/src/num/f128.rs b/library/core/src/num/f128.rs
index 3b03cde0372..4fe4735e304 100644
--- a/library/core/src/num/f128.rs
+++ b/library/core/src/num/f128.rs
@@ -33,12 +33,12 @@ pub mod consts {
 
     /// The golden ratio (φ)
     #[unstable(feature = "f128", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const PHI: f128 = 1.61803398874989484820458683436563811772030917980576286213545_f128;
 
     /// The Euler-Mascheroni constant (γ)
     #[unstable(feature = "f128", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const EGAMMA: f128 = 0.577215664901532860606512090082402431042159335939923598805767_f128;
 
     /// π/2
@@ -67,14 +67,14 @@ pub mod consts {
 
     /// 1/sqrt(π)
     #[unstable(feature = "f128", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_PI: f128 =
         0.564189583547756286948079451560772585844050629328998856844086_f128;
 
     /// 1/sqrt(2π)
     #[doc(alias = "FRAC_1_SQRT_TAU")]
     #[unstable(feature = "f128", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_2PI: f128 =
         0.398942280401432677939946059934381868475858631164934657665926_f128;
 
@@ -98,12 +98,12 @@ pub mod consts {
 
     /// sqrt(3)
     #[unstable(feature = "f128", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const SQRT_3: f128 = 1.73205080756887729352744634150587236694280525381038062805581_f128;
 
     /// 1/sqrt(3)
     #[unstable(feature = "f128", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_3: f128 =
         0.577350269189625764509148780501957455647601751270126876018602_f128;
 
@@ -1659,7 +1659,8 @@ impl f128 {
     #[doc(alias = "fmaf128", alias = "fusedMultiplyAdd")]
     #[unstable(feature = "f128", issue = "116909")]
     #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn mul_add(self, a: f128, b: f128) -> f128 {
+    #[rustc_const_unstable(feature = "const_mul_add", issue = "146724")]
+    pub const fn mul_add(self, a: f128, b: f128) -> f128 {
         intrinsics::fmaf128(self, a, b)
     }
 
diff --git a/library/core/src/num/f16.rs b/library/core/src/num/f16.rs
index a027d63005b..0bea6bc8801 100644
--- a/library/core/src/num/f16.rs
+++ b/library/core/src/num/f16.rs
@@ -35,12 +35,12 @@ pub mod consts {
 
     /// The golden ratio (φ)
     #[unstable(feature = "f16", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const PHI: f16 = 1.618033988749894848204586834365638118_f16;
 
     /// The Euler-Mascheroni constant (γ)
     #[unstable(feature = "f16", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const EGAMMA: f16 = 0.577215664901532860606512090082402431_f16;
 
     /// π/2
@@ -69,13 +69,13 @@ pub mod consts {
 
     /// 1/sqrt(π)
     #[unstable(feature = "f16", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_PI: f16 = 0.564189583547756286948079451560772586_f16;
 
     /// 1/sqrt(2π)
     #[doc(alias = "FRAC_1_SQRT_TAU")]
     #[unstable(feature = "f16", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_2PI: f16 = 0.398942280401432677939946059934381868_f16;
 
     /// 2/π
@@ -96,12 +96,12 @@ pub mod consts {
 
     /// sqrt(3)
     #[unstable(feature = "f16", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const SQRT_3: f16 = 1.732050807568877293527446341505872367_f16;
 
     /// 1/sqrt(3)
     #[unstable(feature = "f16", issue = "116909")]
-    // Also, #[unstable(feature = "more_float_constants", issue = "103883")]
+    // Also, #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_3: f16 = 0.577350269189625764509148780501957456_f16;
 
     /// Euler's number (e)
@@ -1634,7 +1634,8 @@ impl f16 {
     #[unstable(feature = "f16", issue = "116909")]
     #[doc(alias = "fmaf16", alias = "fusedMultiplyAdd")]
     #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn mul_add(self, a: f16, b: f16) -> f16 {
+    #[rustc_const_unstable(feature = "const_mul_add", issue = "146724")]
+    pub const fn mul_add(self, a: f16, b: f16) -> f16 {
         intrinsics::fmaf16(self, a, b)
     }
 
diff --git a/library/core/src/num/f32.rs b/library/core/src/num/f32.rs
index bfc091c54b2..e380cc698f5 100644
--- a/library/core/src/num/f32.rs
+++ b/library/core/src/num/f32.rs
@@ -291,11 +291,11 @@ pub mod consts {
     pub const TAU: f32 = 6.28318530717958647692528676655900577_f32;
 
     /// The golden ratio (φ)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const PHI: f32 = 1.618033988749894848204586834365638118_f32;
 
     /// The Euler-Mascheroni constant (γ)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const EGAMMA: f32 = 0.577215664901532860606512090082402431_f32;
 
     /// π/2
@@ -323,12 +323,12 @@ pub mod consts {
     pub const FRAC_1_PI: f32 = 0.318309886183790671537767526745028724_f32;
 
     /// 1/sqrt(π)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_PI: f32 = 0.564189583547756286948079451560772586_f32;
 
     /// 1/sqrt(2π)
     #[doc(alias = "FRAC_1_SQRT_TAU")]
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_2PI: f32 = 0.398942280401432677939946059934381868_f32;
 
     /// 2/π
@@ -348,11 +348,11 @@ pub mod consts {
     pub const FRAC_1_SQRT_2: f32 = 0.707106781186547524400844362104849039_f32;
 
     /// sqrt(3)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const SQRT_3: f32 = 1.732050807568877293527446341505872367_f32;
 
     /// 1/sqrt(3)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_3: f32 = 0.577350269189625764509148780501957456_f32;
 
     /// Euler's number (e)
@@ -1798,7 +1798,8 @@ pub mod math {
     #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
     #[must_use = "method returns a new number and does not mutate the original value"]
     #[unstable(feature = "core_float_math", issue = "137578")]
-    pub fn mul_add(x: f32, y: f32, z: f32) -> f32 {
+    #[rustc_const_unstable(feature = "const_mul_add", issue = "146724")]
+    pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 {
         intrinsics::fmaf32(x, y, z)
     }
 
diff --git a/library/core/src/num/f64.rs b/library/core/src/num/f64.rs
index 21cd77d8014..ff7449fd996 100644
--- a/library/core/src/num/f64.rs
+++ b/library/core/src/num/f64.rs
@@ -291,11 +291,11 @@ pub mod consts {
     pub const TAU: f64 = 6.28318530717958647692528676655900577_f64;
 
     /// The golden ratio (φ)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const PHI: f64 = 1.618033988749894848204586834365638118_f64;
 
     /// The Euler-Mascheroni constant (γ)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const EGAMMA: f64 = 0.577215664901532860606512090082402431_f64;
 
     /// π/2
@@ -323,12 +323,12 @@ pub mod consts {
     pub const FRAC_1_PI: f64 = 0.318309886183790671537767526745028724_f64;
 
     /// 1/sqrt(π)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_PI: f64 = 0.564189583547756286948079451560772586_f64;
 
     /// 1/sqrt(2π)
     #[doc(alias = "FRAC_1_SQRT_TAU")]
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_2PI: f64 = 0.398942280401432677939946059934381868_f64;
 
     /// 2/π
@@ -348,11 +348,11 @@ pub mod consts {
     pub const FRAC_1_SQRT_2: f64 = 0.707106781186547524400844362104849039_f64;
 
     /// sqrt(3)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const SQRT_3: f64 = 1.732050807568877293527446341505872367_f64;
 
     /// 1/sqrt(3)
-    #[unstable(feature = "more_float_constants", issue = "103883")]
+    #[unstable(feature = "more_float_constants", issue = "146939")]
     pub const FRAC_1_SQRT_3: f64 = 0.577350269189625764509148780501957456_f64;
 
     /// Euler's number (e)
@@ -1796,7 +1796,8 @@ pub mod math {
     #[doc(alias = "fma", alias = "fusedMultiplyAdd")]
     #[unstable(feature = "core_float_math", issue = "137578")]
     #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn mul_add(x: f64, a: f64, b: f64) -> f64 {
+    #[rustc_const_unstable(feature = "const_mul_add", issue = "146724")]
+    pub const fn mul_add(x: f64, a: f64, b: f64) -> f64 {
         intrinsics::fmaf64(x, a, b)
     }
 
diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index 0d80c40fb23..c3460a64090 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -519,8 +519,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -609,8 +609,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_unsigned(3);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -659,8 +659,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub(3);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -749,8 +749,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub_unsigned(3);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -799,8 +799,8 @@ macro_rules! int_impl {
         /// ``` should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -906,8 +906,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -973,8 +973,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1139,8 +1139,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem(-1);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1205,8 +1205,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem_euclid(-1);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1286,8 +1286,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_neg();")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1342,8 +1342,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 0x1", stringify!($SelfT), ".strict_shl(129);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1517,8 +1517,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(128);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1693,8 +1693,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_abs();")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1762,8 +1762,8 @@ macro_rules! int_impl {
         /// ```should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index 1b7c28bb95a..d9184e3c9c2 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -548,6 +548,18 @@ macro_rules! nonzero_integer {
         #[doc = concat!("assert_eq!(align_of::<", stringify!($Ty), ">(), align_of::<Option<", stringify!($Ty), ">>());")]
         /// ```
         ///
+        /// # Compile-time creation
+        ///
+        /// Since both [`Option::unwrap()`] and [`Option::expect()`] are `const`, it is possible to
+        /// define a new
+        #[doc = concat!("`", stringify!($Ty), "`")]
+        /// at compile time via:
+        /// ```
+        #[doc = concat!("use std::num::", stringify!($Ty), ";")]
+        ///
+        #[doc = concat!("const TEN: ", stringify!($Ty), " = ", stringify!($Ty) , r#"::new(10).expect("ten is non-zero");"#)]
+        /// ```
+        ///
         /// [null pointer optimization]: crate::option#representation
         #[$stability]
         pub type $Ty = NonZero<$Int>;
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index d68c7be9865..752498bfbd8 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -667,8 +667,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -762,8 +762,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_signed(3);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -821,8 +821,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 0", stringify!($SelfT), ".strict_sub(1);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -946,8 +946,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX).strict_sub_signed(-1);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1002,8 +1002,8 @@ macro_rules! uint_impl {
             "::MAX), Some(0));"
         )]
         /// ```
-        #[stable(feature = "unsigned_signed_diff", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "unsigned_signed_diff", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "unsigned_signed_diff", since = "1.91.0")]
+        #[rustc_const_stable(feature = "unsigned_signed_diff", since = "1.91.0")]
         #[inline]
         pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> {
             let res = self.wrapping_sub(rhs) as $SignedT;
@@ -1055,8 +1055,8 @@ macro_rules! uint_impl {
         /// ``` should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1151,8 +1151,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline(always)]
@@ -1205,8 +1205,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline(always)]
@@ -1353,8 +1353,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline(always)]
@@ -1409,8 +1409,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline(always)]
@@ -1694,8 +1694,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1750,8 +1750,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shl(129);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -1922,8 +1922,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(129);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -2104,8 +2104,8 @@ macro_rules! uint_impl {
         /// ```should_panic
         #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
         /// ```
-        #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
-        #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
+        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
@@ -2682,7 +2682,7 @@ macro_rules! uint_impl {
         ///
         /// assert_eq!((sum1, sum0), (9, 6));
         /// ```
-        #[stable(feature = "unsigned_bigint_helpers", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
         #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
@@ -2774,7 +2774,7 @@ macro_rules! uint_impl {
         ///
         #[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")]
         /// ```
-        #[stable(feature = "unsigned_bigint_helpers", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
         #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
@@ -2991,7 +2991,7 @@ macro_rules! uint_impl {
         ///     789_u16.wrapping_mul(456).wrapping_add(123),
         /// );
         /// ```
-        #[stable(feature = "unsigned_bigint_helpers", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
         #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
@@ -3057,7 +3057,7 @@ macro_rules! uint_impl {
         ///     u32::to_le_bytes(0xcffc982d)
         /// );
         /// ```
-        #[stable(feature = "unsigned_bigint_helpers", since = "CURRENT_RUSTC_VERSION")]
+        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
         #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
diff --git a/library/core/src/ops/mod.rs b/library/core/src/ops/mod.rs
index 87dd873fdb5..ab1ad407ee2 100644
--- a/library/core/src/ops/mod.rs
+++ b/library/core/src/ops/mod.rs
@@ -149,6 +149,7 @@ mod function;
 mod index;
 mod index_range;
 mod range;
+mod reborrow;
 mod try_trait;
 mod unsize;
 
@@ -189,6 +190,8 @@ pub use self::range::{Bound, RangeBounds, RangeInclusive, RangeToInclusive};
 pub use self::range::{OneSidedRange, OneSidedRangeBound};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::range::{Range, RangeFrom, RangeFull, RangeTo};
+#[unstable(feature = "reborrow", issue = "145612")]
+pub use self::reborrow::{CoerceShared, Reborrow};
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
 pub use self::try_trait::Residual;
 #[unstable(feature = "try_trait_v2_yeet", issue = "96374")]
diff --git a/library/core/src/ops/reborrow.rs b/library/core/src/ops/reborrow.rs
new file mode 100644
index 00000000000..f83f4233a4d
--- /dev/null
+++ b/library/core/src/ops/reborrow.rs
@@ -0,0 +1,16 @@
+/// Allows value to be reborrowed as exclusive, creating a copy of the value
+/// that disables the source for reads and writes for the lifetime of the copy.
+#[lang = "reborrow"]
+#[unstable(feature = "reborrow", issue = "145612")]
+pub trait Reborrow {
+    // Empty.
+}
+
+/// Allows reborrowable value to be reborrowed as shared, creating a copy
+/// that disables the source for writes for the lifetime of the copy.
+#[lang = "coerce_shared"]
+#[unstable(feature = "reborrow", issue = "145612")]
+pub trait CoerceShared: Reborrow {
+    /// The type of this value when reborrowed as shared.
+    type Target: Copy;
+}
diff --git a/library/core/src/os/darwin/objc.rs b/library/core/src/os/darwin/objc.rs
index 928cb54e82c..df3aab867e8 100644
--- a/library/core/src/os/darwin/objc.rs
+++ b/library/core/src/os/darwin/objc.rs
@@ -6,7 +6,7 @@
 use crate::fmt;
 
 /// Equivalent to Objective-C’s `struct objc_class` type.
-#[cfg_attr(not(doc), repr(u8))] // An implementation detail we don't want to show up in rustdoc
+#[repr(u8)]
 pub enum objc_class {
     #[unstable(
         feature = "objc_class_variant",
@@ -31,7 +31,7 @@ impl fmt::Debug for objc_class {
 }
 
 /// Equivalent to Objective-C’s `struct objc_selector` type.
-#[cfg_attr(not(doc), repr(u8))] // An implementation detail we don't want to show up in rustdoc
+#[repr(u8)]
 pub enum objc_selector {
     #[unstable(
         feature = "objc_selector_variant",
diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs
index 625024373ef..b29d2676542 100644
--- a/library/core/src/ptr/mod.rs
+++ b/library/core/src/ptr/mod.rs
@@ -975,7 +975,7 @@ pub const fn dangling_mut<T>() -> *mut T {
 #[must_use]
 #[inline(always)]
 #[stable(feature = "exposed_provenance", since = "1.84.0")]
-#[rustc_const_stable(feature = "const_exposed_provenance", since = "CURRENT_RUSTC_VERSION")]
+#[rustc_const_stable(feature = "const_exposed_provenance", since = "1.91.0")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[allow(fuzzy_provenance_casts)] // this *is* the explicit provenance API one should use instead
 pub const fn with_exposed_provenance<T>(addr: usize) -> *const T {
@@ -1016,7 +1016,7 @@ pub const fn with_exposed_provenance<T>(addr: usize) -> *const T {
 #[must_use]
 #[inline(always)]
 #[stable(feature = "exposed_provenance", since = "1.84.0")]
-#[rustc_const_stable(feature = "const_exposed_provenance", since = "CURRENT_RUSTC_VERSION")]
+#[rustc_const_stable(feature = "const_exposed_provenance", since = "1.91.0")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[allow(fuzzy_provenance_casts)] // this *is* the explicit provenance API one should use instead
 pub const fn with_exposed_provenance_mut<T>(addr: usize) -> *mut T {
diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs
index 2e473d348b0..3a5efa7d835 100644
--- a/library/core/src/str/mod.rs
+++ b/library/core/src/str/mod.rs
@@ -404,8 +404,8 @@ impl str {
     /// assert_eq!(closest, 10);
     /// assert_eq!(&s[..closest], "❤️🧡");
     /// ```
-    #[stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "round_char_boundary", since = "1.91.0")]
+    #[rustc_const_stable(feature = "round_char_boundary", since = "1.91.0")]
     #[inline]
     pub const fn floor_char_boundary(&self, index: usize) -> usize {
         if index >= self.len() {
@@ -447,8 +447,8 @@ impl str {
     /// assert_eq!(closest, 14);
     /// assert_eq!(&s[..closest], "❤️🧡💛");
     /// ```
-    #[stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "round_char_boundary", since = "1.91.0")]
+    #[rustc_const_stable(feature = "round_char_boundary", since = "1.91.0")]
     #[inline]
     pub const fn ceil_char_boundary(&self, index: usize) -> usize {
         if index >= self.len() {
diff --git a/library/core/src/sync/atomic.rs b/library/core/src/sync/atomic.rs
index 1b4a54b1b7a..30a42d4eb5e 100644
--- a/library/core/src/sync/atomic.rs
+++ b/library/core/src/sync/atomic.rs
@@ -2208,7 +2208,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[cfg(target_has_atomic = "ptr")]
-    #[stable(feature = "strict_provenance_atomic_ptr", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "strict_provenance_atomic_ptr", since = "1.91.0")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub fn fetch_ptr_add(&self, val: usize, order: Ordering) -> *mut T {
         self.fetch_byte_add(val.wrapping_mul(size_of::<T>()), order)
@@ -2252,7 +2252,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[cfg(target_has_atomic = "ptr")]
-    #[stable(feature = "strict_provenance_atomic_ptr", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "strict_provenance_atomic_ptr", since = "1.91.0")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub fn fetch_ptr_sub(&self, val: usize, order: Ordering) -> *mut T {
         self.fetch_byte_sub(val.wrapping_mul(size_of::<T>()), order)
@@ -2286,7 +2286,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[cfg(target_has_atomic = "ptr")]
-    #[stable(feature = "strict_provenance_atomic_ptr", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "strict_provenance_atomic_ptr", since = "1.91.0")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub fn fetch_byte_add(&self, val: usize, order: Ordering) -> *mut T {
         // SAFETY: data races are prevented by atomic intrinsics.
@@ -2321,7 +2321,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[cfg(target_has_atomic = "ptr")]
-    #[stable(feature = "strict_provenance_atomic_ptr", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "strict_provenance_atomic_ptr", since = "1.91.0")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub fn fetch_byte_sub(&self, val: usize, order: Ordering) -> *mut T {
         // SAFETY: data races are prevented by atomic intrinsics.
@@ -2371,7 +2371,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[cfg(target_has_atomic = "ptr")]
-    #[stable(feature = "strict_provenance_atomic_ptr", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "strict_provenance_atomic_ptr", since = "1.91.0")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub fn fetch_or(&self, val: usize, order: Ordering) -> *mut T {
         // SAFETY: data races are prevented by atomic intrinsics.
@@ -2420,7 +2420,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[cfg(target_has_atomic = "ptr")]
-    #[stable(feature = "strict_provenance_atomic_ptr", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "strict_provenance_atomic_ptr", since = "1.91.0")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub fn fetch_and(&self, val: usize, order: Ordering) -> *mut T {
         // SAFETY: data races are prevented by atomic intrinsics.
@@ -2467,7 +2467,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[cfg(target_has_atomic = "ptr")]
-    #[stable(feature = "strict_provenance_atomic_ptr", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "strict_provenance_atomic_ptr", since = "1.91.0")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub fn fetch_xor(&self, val: usize, order: Ordering) -> *mut T {
         // SAFETY: data races are prevented by atomic intrinsics.
diff --git a/library/core/src/sync/exclusive.rs b/library/core/src/sync/exclusive.rs
index cf086bf4f50..f181c5514f2 100644
--- a/library/core/src/sync/exclusive.rs
+++ b/library/core/src/sync/exclusive.rs
@@ -1,28 +1,32 @@
 //! Defines [`Exclusive`].
 
+use core::cmp::Ordering;
 use core::fmt;
 use core::future::Future;
-use core::marker::Tuple;
+use core::hash::{Hash, Hasher};
+use core::marker::{StructuralPartialEq, Tuple};
 use core::ops::{Coroutine, CoroutineState};
 use core::pin::Pin;
 use core::task::{Context, Poll};
 
-/// `Exclusive` provides only _mutable_ access, also referred to as _exclusive_
-/// access to the underlying value. It provides no _immutable_, or _shared_
-/// access to the underlying value.
+/// `Exclusive` provides _mutable_ access, also referred to as _exclusive_
+/// access to the underlying value. However, it only permits _immutable_, or _shared_
+/// access to the underlying value when that value is [`Sync`].
 ///
 /// While this may seem not very useful, it allows `Exclusive` to _unconditionally_
-/// implement [`Sync`]. Indeed, the safety requirements of `Sync` state that for `Exclusive`
+/// implement `Sync`. Indeed, the safety requirements of `Sync` state that for `Exclusive`
 /// to be `Sync`, it must be sound to _share_ across threads, that is, it must be sound
-/// for `&Exclusive` to cross thread boundaries. By design, a `&Exclusive` has no API
-/// whatsoever, making it useless, thus harmless, thus memory safe.
+/// for `&Exclusive` to cross thread boundaries. By design, a `&Exclusive<T>` for non-`Sync` T
+/// has no API whatsoever, making it useless, thus harmless, thus memory safe.
 ///
 /// Certain constructs like [`Future`]s can only be used with _exclusive_ access,
 /// and are often `Send` but not `Sync`, so `Exclusive` can be used as hint to the
 /// Rust compiler that something is `Sync` in practice.
 ///
 /// ## Examples
-/// Using a non-`Sync` future prevents the wrapping struct from being `Sync`
+///
+/// Using a non-`Sync` future prevents the wrapping struct from being `Sync`:
+///
 /// ```compile_fail
 /// use core::cell::Cell;
 ///
@@ -43,7 +47,8 @@ use core::task::{Context, Poll};
 /// ```
 ///
 /// `Exclusive` ensures the struct is `Sync` without stripping the future of its
-/// functionality.
+/// functionality:
+///
 /// ```
 /// #![feature(exclusive_wrapper)]
 /// use core::cell::Cell;
@@ -66,6 +71,7 @@ use core::task::{Context, Poll};
 /// ```
 ///
 /// ## Parallels with a mutex
+///
 /// In some sense, `Exclusive` can be thought of as a _compile-time_ version of
 /// a mutex, as the borrow-checker guarantees that only one `&mut` can exist
 /// for any value. This is a parallel with the fact that
@@ -75,7 +81,7 @@ use core::task::{Context, Poll};
 #[doc(alias = "SyncWrapper")]
 #[doc(alias = "SyncCell")]
 #[doc(alias = "Unique")]
-// `Exclusive` can't have `PartialOrd`, `Clone`, etc. impls as they would
+// `Exclusive` can't have derived `PartialOrd`, `Clone`, etc. impls as they would
 // use `&` access to the inner value, violating the `Sync` impl's safety
 // requirements.
 #[derive(Default)]
@@ -196,6 +202,17 @@ where
 }
 
 #[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<F, Args> Fn<Args> for Exclusive<F>
+where
+    F: Sync + Fn<Args>,
+    Args: Tuple,
+{
+    extern "rust-call" fn call(&self, args: Args) -> Self::Output {
+        self.as_ref().call(args)
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
 impl<T> Future for Exclusive<T>
 where
     T: Future + ?Sized,
@@ -221,3 +238,80 @@ where
         G::resume(self.get_pin_mut(), arg)
     }
 }
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> AsRef<T> for Exclusive<T>
+where
+    T: Sync + ?Sized,
+{
+    #[inline]
+    fn as_ref(&self) -> &T {
+        &self.inner
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> Clone for Exclusive<T>
+where
+    T: Sync + Clone,
+{
+    #[inline]
+    fn clone(&self) -> Self {
+        Self { inner: self.inner.clone() }
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> Copy for Exclusive<T> where T: Sync + Copy {}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T, U> PartialEq<Exclusive<U>> for Exclusive<T>
+where
+    T: Sync + PartialEq<U> + ?Sized,
+    U: Sync + ?Sized,
+{
+    #[inline]
+    fn eq(&self, other: &Exclusive<U>) -> bool {
+        self.inner == other.inner
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> StructuralPartialEq for Exclusive<T> where T: Sync + StructuralPartialEq + ?Sized {}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> Eq for Exclusive<T> where T: Sync + Eq + ?Sized {}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> Hash for Exclusive<T>
+where
+    T: Sync + Hash + ?Sized,
+{
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        Hash::hash(&self.inner, state)
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T, U> PartialOrd<Exclusive<U>> for Exclusive<T>
+where
+    T: Sync + PartialOrd<U> + ?Sized,
+    U: Sync + ?Sized,
+{
+    #[inline]
+    fn partial_cmp(&self, other: &Exclusive<U>) -> Option<Ordering> {
+        self.inner.partial_cmp(&other.inner)
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> Ord for Exclusive<T>
+where
+    T: Sync + Ord + ?Sized,
+{
+    #[inline]
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.inner.cmp(&other.inner)
+    }
+}
diff --git a/library/core/src/time.rs b/library/core/src/time.rs
index d205bc376f1..f721fcd6156 100644
--- a/library/core/src/time.rs
+++ b/library/core/src/time.rs
@@ -416,8 +416,8 @@ impl Duration {
     /// assert_eq!(6 * 60 * 60, duration.as_secs());
     /// assert_eq!(0, duration.subsec_nanos());
     /// ```
-    #[stable(feature = "duration_constructors_lite", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "duration_constructors_lite", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "duration_constructors_lite", since = "1.91.0")]
+    #[rustc_const_stable(feature = "duration_constructors_lite", since = "1.91.0")]
     #[must_use]
     #[inline]
     pub const fn from_hours(hours: u64) -> Duration {
@@ -444,8 +444,8 @@ impl Duration {
     /// assert_eq!(10 * 60, duration.as_secs());
     /// assert_eq!(0, duration.subsec_nanos());
     /// ```
-    #[stable(feature = "duration_constructors_lite", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "duration_constructors_lite", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "duration_constructors_lite", since = "1.91.0")]
+    #[rustc_const_stable(feature = "duration_constructors_lite", since = "1.91.0")]
     #[must_use]
     #[inline]
     pub const fn from_mins(mins: u64) -> Duration {