Stabilize const unchecked conversion from u32 to char

Author: dtolnay

core/src/char/methods.rs

@@ -223,7 +223,10 @@ impl char {
     /// assert_eq!('❤', c);
     /// ```
     #[stable(feature = "assoc_char_funcs", since = "1.52.0")]
-    #[rustc_const_unstable(feature = "const_char_from_u32_unchecked", issue = "89259")]
+    #[rustc_const_stable(
+        feature = "const_char_from_u32_unchecked",
+        since = "CURRENT_RUSTC_VERSION"
+    )]
     #[must_use]
     #[inline]
     pub const unsafe fn from_u32_unchecked(i: u32) -> char {

core/src/char/mod.rs

@@ -123,7 +123,7 @@ pub const fn from_u32(i: u32) -> Option<char> {
 /// Converts a `u32` to a `char`, ignoring validity. Use [`char::from_u32_unchecked`].
 /// instead.
 #[stable(feature = "char_from_unchecked", since = "1.5.0")]
-#[rustc_const_unstable(feature = "const_char_from_u32_unchecked", issue = "89259")]
+#[rustc_const_stable(feature = "const_char_from_u32_unchecked", since = "CURRENT_RUSTC_VERSION")]
 #[must_use]
 #[inline]
 pub const unsafe fn from_u32_unchecked(i: u32) -> char {

core/src/lib.rs

@@ -122,7 +122,6 @@
 #![feature(const_bigint_helper_methods)]
 #![feature(const_black_box)]
 #![feature(const_cell_into_inner)]
-#![feature(const_char_from_u32_unchecked)]
 #![feature(const_eval_select)]
 #![feature(const_exact_div)]
 #![feature(const_float_bits_conv)]