stabilize const_int_pow

Also stabilize constctlz for const ctlz_nonzero.

The public methods stabilized const by this commit are:

  * `{i*,u*}::checked_pow`
  * `{i*,u*}::saturating_pow`
  * `{i*,u*}::wrapping_pow`
  * `{i*,u*}::overflowing_pow`
  * `{i*,u*}::pow`
  * `u*::next_power_of_two`
  * `u*::checked_next_power_of_two`
  * `u*::wrapping_next_power_of_two` (the method itself is still unstable)

Author: tspiteri

library/core/src/intrinsics.rs

@@ -1486,7 +1486,7 @@ extern "rust-intrinsic" {
     /// let num_leading = unsafe { ctlz_nonzero(x) };
     /// assert_eq!(num_leading, 3);
     /// ```
-    #[rustc_const_unstable(feature = "constctlz", issue = "none")]
+    #[rustc_const_stable(feature = "constctlz", since = "1.49.0")]
     pub fn ctlz_nonzero<T: Copy>(x: T) -> T;
 
     /// Returns the number of trailing unset bits (zeroes) in an integer type `T`.

library/core/src/lib.rs

@@ -78,8 +78,6 @@
 #![feature(const_overflowing_int_methods)]
 #![feature(const_int_unchecked_arith)]
 #![feature(const_mut_refs)]
-#![feature(const_int_pow)]
-#![feature(constctlz)]
 #![feature(const_cttz)]
 #![feature(const_panic)]
 #![feature(const_pin)]

library/core/src/num/int_macros.rs

@@ -791,7 +791,7 @@ $EndFeature, "
 ```"),
 
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -974,7 +974,7 @@ assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT
 $EndFeature, "
 ```"),
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -1340,7 +1340,7 @@ assert_eq!(3i8.wrapping_pow(6), -39);",
 $EndFeature, "
 ```"),
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -1707,7 +1707,7 @@ assert_eq!(3i8.overflowing_pow(5), (-13, true));",
 $EndFeature, "
 ```"),
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -1757,7 +1757,7 @@ assert_eq!(x.pow(5), 32);",
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]

library/core/src/num/uint_macros.rs

@@ -749,7 +749,7 @@ Basic usage:
 assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);", $EndFeature, "
 ```"),
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -865,7 +865,7 @@ assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT
 $EndFeature, "
 ```"),
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -1159,7 +1159,7 @@ Basic usage:
 assert_eq!(3u8.wrapping_pow(6), 217);", $EndFeature, "
 ```"),
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -1484,7 +1484,7 @@ Basic usage:
 assert_eq!(3u8.overflowing_pow(6), (217, true));", $EndFeature, "
 ```"),
             #[stable(feature = "no_panic_pow", since = "1.34.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
             #[inline]
@@ -1532,7 +1532,7 @@ Basic usage:
 ", $Feature, "assert_eq!(2", stringify!($SelfT), ".pow(5), 32);", $EndFeature, "
 ```"),
         #[stable(feature = "rust1", since = "1.0.0")]
-        #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+        #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
         #[must_use = "this returns the result of the operation, \
                           without modifying the original"]
         #[inline]
@@ -1648,7 +1648,7 @@ assert!(!10", stringify!($SelfT), ".is_power_of_two());", $EndFeature, "
         // overflow cases it instead ends up returning the maximum value
         // of the type, and can return 0 for 0.
         #[inline]
-        #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+        #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
         const fn one_less_than_next_power_of_two(self) -> Self {
             if self <= 1 { return 0; }
 
@@ -1677,7 +1677,7 @@ Basic usage:
 assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             #[inline]
             #[rustc_inherit_overflow_checks]
             pub const fn next_power_of_two(self) -> Self {
@@ -1703,7 +1703,7 @@ $EndFeature, "
 ```"),
             #[inline]
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             pub const fn checked_next_power_of_two(self) -> Option<Self> {
                 self.one_less_than_next_power_of_two().checked_add(1)
             }
@@ -1728,7 +1728,7 @@ $EndFeature, "
 ```"),
             #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
                        reason = "needs decision on wrapping behaviour")]
-            #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
+            #[rustc_const_stable(feature = "const_int_pow", since = "1.49.0")]
             pub const fn wrapping_next_power_of_two(self) -> Self {
                 self.one_less_than_next_power_of_two().wrapping_add(1)
             }

src/test/ui/consts/const-int-pow-rpass.rs

@@ -1,6 +1,5 @@
 // run-pass
 
-#![feature(const_int_pow)]
 #![feature(wrapping_next_power_of_two)]
 
 const IS_POWER_OF_TWO_A: bool = 0u32.is_power_of_two();