diff --git a/core/src/char/methods.rs b/core/src/char/methods.rs
index 6bedb0d0dc4e5..04698193bba1e 100644
--- a/core/src/char/methods.rs
+++ b/core/src/char/methods.rs
@@ -1282,8 +1282,9 @@ impl char {
     ///
     /// [`to_ascii_uppercase()`]: #method.to_ascii_uppercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_uppercase(&mut self) {
         *self = self.to_ascii_uppercase();
     }
@@ -1308,8 +1309,9 @@ impl char {
     ///
     /// [`to_ascii_lowercase()`]: #method.to_ascii_lowercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_lowercase(&mut self) {
         *self = self.to_ascii_lowercase();
     }
diff --git a/core/src/lib.rs b/core/src/lib.rs
index 08c0d6e34cd02..674bf075551d7 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -125,7 +125,6 @@
 #![feature(const_heap)]
 #![feature(const_index_range_slice_index)]
 #![feature(const_likely)]
-#![feature(const_make_ascii)]
 #![feature(const_nonnull_new)]
 #![feature(const_num_midpoint)]
 #![feature(const_option_ext)]
diff --git a/core/src/num/mod.rs b/core/src/num/mod.rs
index 31e35015d2de1..f55d55171f29f 100644
--- a/core/src/num/mod.rs
+++ b/core/src/num/mod.rs
@@ -624,8 +624,9 @@ impl u8 {
     ///
     /// [`to_ascii_uppercase`]: Self::to_ascii_uppercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_uppercase(&mut self) {
         *self = self.to_ascii_uppercase();
     }
@@ -650,8 +651,9 @@ impl u8 {
     ///
     /// [`to_ascii_lowercase`]: Self::to_ascii_lowercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_lowercase(&mut self) {
         *self = self.to_ascii_lowercase();
     }
diff --git a/core/src/slice/ascii.rs b/core/src/slice/ascii.rs
index 8f8050fdc3aaf..8d8ac6a1d2a1c 100644
--- a/core/src/slice/ascii.rs
+++ b/core/src/slice/ascii.rs
@@ -67,8 +67,9 @@ impl [u8] {
     ///
     /// [`to_ascii_uppercase`]: #method.to_ascii_uppercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_uppercase(&mut self) {
         // FIXME(const-hack): We would like to simply iterate using `for` loops but this isn't currently allowed in constant expressions.
         let mut i = 0;
@@ -89,8 +90,9 @@ impl [u8] {
     ///
     /// [`to_ascii_lowercase`]: #method.to_ascii_lowercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_lowercase(&mut self) {
         // FIXME(const-hack): We would like to simply iterate using `for` loops but this isn't currently allowed in constant expressions.
         let mut i = 0;
diff --git a/core/src/str/mod.rs b/core/src/str/mod.rs
index e93c52f27999e..1d10015d75a26 100644
--- a/core/src/str/mod.rs
+++ b/core/src/str/mod.rs
@@ -2475,8 +2475,9 @@ impl str {
     /// assert_eq!("GRüßE, JüRGEN ❤", s);
     /// ```
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_uppercase(&mut self) {
         // SAFETY: changing ASCII letters only does not invalidate UTF-8.
         let me = unsafe { self.as_bytes_mut() };
@@ -2503,8 +2504,9 @@ impl str {
     /// assert_eq!("grÜße, jÜrgen ❤", s);
     /// ```
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
+    #[rustc_const_stable(feature = "const_make_ascii", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
+    #[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
     pub const fn make_ascii_lowercase(&mut self) {
         // SAFETY: changing ASCII letters only does not invalidate UTF-8.
         let me = unsafe { self.as_bytes_mut() };