diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index b2e22d8715a8b..aa9b632cbed9e 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -2643,15 +2643,13 @@ impl<T, A: Allocator, const N: usize> Vec<[T; N], A> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(slice_flatten)]
-    ///
     /// let mut vec = vec![[1, 2, 3], [4, 5, 6], [7, 8, 9]];
     /// assert_eq!(vec.pop(), Some([7, 8, 9]));
     ///
     /// let mut flattened = vec.into_flattened();
     /// assert_eq!(flattened.pop(), Some(6));
     /// ```
-    #[unstable(feature = "slice_flatten", issue = "95629")]
+    #[stable(feature = "slice_flatten", since = "CURRENT_RUSTC_VERSION")]
     pub fn into_flattened(self) -> Vec<T, A> {
         let (ptr, len, cap, alloc) = self.into_raw_parts_with_alloc();
         let (new_len, new_cap) = if T::IS_ZST {
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 0eae4ca4b8ba3..8451be63c2b9b 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -36,7 +36,6 @@
 #![feature(const_str_from_utf8)]
 #![feature(panic_update_hook)]
 #![feature(pointer_is_aligned_to)]
-#![feature(slice_flatten)]
 #![feature(thin_box)]
 #![feature(strict_provenance)]
 #![feature(drain_keep_rest)]
diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index f82f965e67cf4..503107c74803b 100644
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -4531,8 +4531,6 @@ impl<T, const N: usize> [[T; N]] {
     /// # Examples
     ///
     /// ```
-    /// #![feature(slice_flatten)]
-    ///
     /// assert_eq!([[1, 2, 3], [4, 5, 6]].as_flattened(), &[1, 2, 3, 4, 5, 6]);
     ///
     /// assert_eq!(
@@ -4546,7 +4544,8 @@ impl<T, const N: usize> [[T; N]] {
     /// let empty_slice_of_arrays: &[[u32; 10]] = &[];
     /// assert!(empty_slice_of_arrays.as_flattened().is_empty());
     /// ```
-    #[unstable(feature = "slice_flatten", issue = "95629")]
+    #[stable(feature = "slice_flatten", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_unstable(feature = "const_slice_flatten", issue = "95629")]
     pub const fn as_flattened(&self) -> &[T] {
         let len = if T::IS_ZST {
             self.len().checked_mul(N).expect("slice len overflow")
@@ -4572,8 +4571,6 @@ impl<T, const N: usize> [[T; N]] {
     /// # Examples
     ///
     /// ```
-    /// #![feature(slice_flatten)]
-    ///
     /// fn add_5_to_all(slice: &mut [i32]) {
     ///     for i in slice {
     ///         *i += 5;
@@ -4584,7 +4581,7 @@ impl<T, const N: usize> [[T; N]] {
     /// add_5_to_all(array.as_flattened_mut());
     /// assert_eq!(array, [[6, 7, 8], [9, 10, 11], [12, 13, 14]]);
     /// ```
-    #[unstable(feature = "slice_flatten", issue = "95629")]
+    #[stable(feature = "slice_flatten", since = "CURRENT_RUSTC_VERSION")]
     pub fn as_flattened_mut(&mut self) -> &mut [T] {
         let len = if T::IS_ZST {
             self.len().checked_mul(N).expect("slice len overflow")
diff --git a/library/core/tests/lib.rs b/library/core/tests/lib.rs
index e42cec304ef4f..e0f82c916635e 100644
--- a/library/core/tests/lib.rs
+++ b/library/core/tests/lib.rs
@@ -110,7 +110,6 @@
 #![feature(const_array_from_ref)]
 #![feature(const_slice_from_ref)]
 #![feature(waker_getters)]
-#![feature(slice_flatten)]
 #![feature(error_generic_member_access)]
 #![feature(error_in_core)]
 #![feature(trait_upcasting)]