Auto merge of #50465 - clarcharr:wrapping, r=KodrAus

Add missing Wrapping methods, use doc_comment!

Re-opened version of #49393 . Finishing touches for #32463.

Note that this adds `Shl` and `Shr` implementations for `Wrapping<i128>` and `Wrapping<u128>`, which were previously missed. This is technically insta-stable, but I don't know why this would be a problem.

2 files changed, 488 insertions, 199 deletions

diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 232ecb8fbae..013d0334d41 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -168,8 +168,6 @@ impl<T: fmt::UpperHex> fmt::UpperHex for Wrapping<T> {
     }
 }
 
-mod wrapping;
-
 // All these modules are technically private and only exposed for coretests:
 pub mod flt2dec;
 pub mod dec2flt;
@@ -183,6 +181,8 @@ macro_rules! doc_comment {
     };
 }
 
+mod wrapping;
+
 // `Int` + `SignedInt` implemented for signed integers
 macro_rules! int_impl {
     ($SelfT:ty, $ActualT:ident, $UnsignedT:ty, $BITS:expr, $Min:expr, $Max:expr, $Feature:expr,
@@ -3401,6 +3401,30 @@ $EndFeature, "
             }
         }
 
+        doc_comment! {
+            concat!("Returns the smallest power of two greater than or equal to `n`. If
+the next power of two is greater than the type's maximum value,
+the return value is wrapped to `0`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_next_power_of_two)]
+", $Feature, "
+assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);
+assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);
+assert_eq!(", stringify!($SelfT), "::max_value().wrapping_next_power_of_two(), 0);",
+$EndFeature, "
+```"),
+            #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
+                       reason = "needs decision on wrapping behaviour")]
+            pub fn wrapping_next_power_of_two(self) -> Self {
+                self.one_less_than_next_power_of_two().wrapping_add(1)
+            }
+        }
+
         /// Return the memory representation of this integer as a byte array.
         ///
         /// The target platform’s native endianness is used.
diff --git a/src/libcore/num/wrapping.rs b/src/libcore/num/wrapping.rs
index 826883fdc3f..d7f87d37f5b 100644
--- a/src/libcore/num/wrapping.rs
+++ b/src/libcore/num/wrapping.rs
@@ -112,17 +112,19 @@ macro_rules! sh_impl_all {
         //sh_impl_unsigned! { $t, u16 }
         //sh_impl_unsigned! { $t, u32 }
         //sh_impl_unsigned! { $t, u64 }
+        //sh_impl_unsigned! { $t, u128 }
         sh_impl_unsigned! { $t, usize }
 
         //sh_impl_signed! { $t, i8 }
         //sh_impl_signed! { $t, i16 }
         //sh_impl_signed! { $t, i32 }
         //sh_impl_signed! { $t, i64 }
+        //sh_impl_signed! { $t, i128 }
         //sh_impl_signed! { $t, isize }
     )*)
 }
 
-sh_impl_all! { u8 u16 u32 u64 usize i8 i16 i32 i64 isize }
+sh_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
 
 // FIXME(30524): impl Op<T> for Wrapping<T>, impl OpAssign<T> for Wrapping<T>
 macro_rules! wrapping_impl {
@@ -326,88 +328,111 @@ wrapping_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
 macro_rules! wrapping_int_impl {
     ($($t:ty)*) => ($(
         impl Wrapping<$t> {
-            /// Returns the number of ones in the binary representation of
-            /// `self`.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let n: Wrapping<i8> = Wrapping(-0b1000_0000);
-            ///
-            /// assert_eq!(n.count_ones(), 1);
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn count_ones(self) -> u32 {
-                self.0.count_ones()
+            doc_comment! {
+                concat!("Returns the smallest value that can be represented by this integer type.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert_eq!(<Wrapping<", stringify!($t), ">>::min_value(), ",
+"Wrapping(", stringify!($t), "::min_value()));
+```"),
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                #[inline]
+                pub const fn min_value() -> Self {
+                    Wrapping(<$t>::min_value())
+                }
             }
 
-            /// Returns the number of zeros in the binary representation of
-            /// `self`.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let n: Wrapping<i8> = Wrapping(-0b1000_0000);
-            ///
-            /// assert_eq!(n.count_zeros(), 7);
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn count_zeros(self) -> u32 {
-                self.0.count_zeros()
+            doc_comment! {
+                concat!("Returns the largest value that can be represented by this integer type.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert_eq!(<Wrapping<", stringify!($t), ">>::max_value(), ",
+"Wrapping(", stringify!($t), "::max_value()));
+```"),
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                #[inline]
+                pub const fn max_value() -> Self {
+                    Wrapping(<$t>::max_value())
+                }
             }
 
-            /// Returns the number of leading zeros in the binary representation
-            /// of `self`.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let n: Wrapping<i16> = Wrapping(-1);
-            ///
-            /// assert_eq!(n.leading_zeros(), 0);
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn leading_zeros(self) -> u32 {
-                self.0.leading_zeros()
+            doc_comment! {
+                concat!("Returns the number of ones in the binary representation of `self`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(0b01001100", stringify!($t), ");
+
+assert_eq!(n.count_ones(), 3);
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn count_ones(self) -> u32 {
+                    self.0.count_ones()
+                }
             }
 
-            /// Returns the number of trailing zeros in the binary representation
-            /// of `self`.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let n: Wrapping<i8> = Wrapping(-4);
-            ///
-            /// assert_eq!(n.trailing_zeros(), 2);
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn trailing_zeros(self) -> u32 {
-                self.0.trailing_zeros()
+            doc_comment! {
+                concat!("Returns the number of zeros in the binary representation of `self`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert_eq!(Wrapping(!0", stringify!($t), ").count_zeros(), 0);
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn count_zeros(self) -> u32 {
+                    self.0.count_zeros()
+                }
+            }
+
+            doc_comment! {
+                concat!("Returns the number of trailing zeros in the binary representation
+of `self`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(0b0101000", stringify!($t), ");
+
+assert_eq!(n.trailing_zeros(), 3);
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn trailing_zeros(self) -> u32 {
+                    self.0.trailing_zeros()
+                }
             }
 
             /// Shifts the bits to the left by a specified amount, `n`,
@@ -484,145 +509,178 @@ macro_rules! wrapping_int_impl {
                 Wrapping(self.0.swap_bytes())
             }
 
-            /// Converts an integer from big endian to the target's endianness.
-            ///
-            /// On big endian this is a no-op. On little endian the bytes are
-            /// swapped.
+            /// Reverses the bit pattern of the integer.
             ///
             /// # Examples
             ///
+            /// Please note that this example is shared between integer types.
+            /// Which explains why `i16` is used here.
+            ///
             /// Basic usage:
             ///
             /// ```
-            /// #![feature(wrapping_int_impl)]
+            /// #![feature(reverse_bits)]
             /// use std::num::Wrapping;
             ///
-            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
+            /// let n = Wrapping(0b0000000_01010101i16);
+            /// assert_eq!(n, Wrapping(85));
+            ///
+            /// let m = n.reverse_bits();
             ///
-            /// if cfg!(target_endian = "big") {
-            ///     assert_eq!(Wrapping::<i64>::from_be(n), n);
-            /// } else {
-            ///     assert_eq!(Wrapping::<i64>::from_be(n), n.swap_bytes());
-            /// }
+            /// assert_eq!(m.0 as u16, 0b10101010_00000000);
+            /// assert_eq!(m, Wrapping(-22016));
             /// ```
+            #[unstable(feature = "reverse_bits", issue = "48763")]
+            #[cfg(not(stage0))]
             #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn from_be(x: Self) -> Self {
-                Wrapping(<$t>::from_be(x.0))
+            pub fn reverse_bits(self) -> Self {
+                Wrapping(self.0.reverse_bits())
             }
 
-            /// Converts an integer from little endian to the target's endianness.
-            ///
-            /// On little endian this is a no-op. On big endian the bytes are
-            /// swapped.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
-            ///
-            /// if cfg!(target_endian = "little") {
-            ///     assert_eq!(Wrapping::<i64>::from_le(n), n);
-            /// } else {
-            ///     assert_eq!(Wrapping::<i64>::from_le(n), n.swap_bytes());
-            /// }
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn from_le(x: Self) -> Self {
-                Wrapping(<$t>::from_le(x.0))
+            doc_comment! {
+                concat!("Converts an integer from big endian to the target's endianness.
+
+On big endian this is a no-op. On little endian the bytes are
+swapped.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(0x1A", stringify!($t), ");
+
+if cfg!(target_endian = \"big\") {
+    assert_eq!(<Wrapping<", stringify!($t), ">>::from_be(n), n)
+} else {
+    assert_eq!(<Wrapping<", stringify!($t), ">>::from_be(n), n.swap_bytes())
+}
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn from_be(x: Self) -> Self {
+                    Wrapping(<$t>::from_be(x.0))
+                }
             }
 
-            /// Converts `self` to big endian from the target's endianness.
-            ///
-            /// On big endian this is a no-op. On little endian the bytes are
-            /// swapped.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
-            ///
-            /// if cfg!(target_endian = "big") {
-            ///     assert_eq!(n.to_be(), n);
-            /// } else {
-            ///     assert_eq!(n.to_be(), n.swap_bytes());
-            /// }
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn to_be(self) -> Self {
-                Wrapping(self.0.to_be())
+            doc_comment! {
+                concat!("Converts an integer from little endian to the target's endianness.
+
+On little endian this is a no-op. On big endian the bytes are
+swapped.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(0x1A", stringify!($t), ");
+
+if cfg!(target_endian = \"little\") {
+    assert_eq!(<Wrapping<", stringify!($t), ">>::from_le(n), n)
+} else {
+    assert_eq!(<Wrapping<", stringify!($t), ">>::from_le(n), n.swap_bytes())
+}
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn from_le(x: Self) -> Self {
+                    Wrapping(<$t>::from_le(x.0))
+                }
             }
 
-            /// Converts `self` to little endian from the target's endianness.
-            ///
-            /// On little endian this is a no-op. On big endian the bytes are
-            /// swapped.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
-            ///
-            /// if cfg!(target_endian = "little") {
-            ///     assert_eq!(n.to_le(), n);
-            /// } else {
-            ///     assert_eq!(n.to_le(), n.swap_bytes());
-            /// }
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn to_le(self) -> Self {
-                Wrapping(self.0.to_le())
+            doc_comment! {
+                concat!("Converts `self` to big endian from the target's endianness.
+
+On big endian this is a no-op. On little endian the bytes are
+swapped.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(0x1A", stringify!($t), ");
+
+if cfg!(target_endian = \"big\") {
+    assert_eq!(n.to_be(), n)
+} else {
+    assert_eq!(n.to_be(), n.swap_bytes())
+}
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn to_be(self) -> Self {
+                    Wrapping(self.0.to_be())
+                }
             }
 
-            /// Raises self to the power of `exp`, using exponentiation by
-            /// squaring.
-            ///
-            /// # Examples
-            ///
-            /// Basic usage:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// let x: Wrapping<i32> = Wrapping(2); // or any other integer type
-            ///
-            /// assert_eq!(x.pow(4), Wrapping(16));
-            /// ```
-            ///
-            /// Results that are too large are wrapped:
-            ///
-            /// ```
-            /// #![feature(wrapping_int_impl)]
-            /// use std::num::Wrapping;
-            ///
-            /// // 5 ^ 4 = 625, which is too big for a u8
-            /// let x: Wrapping<u8> = Wrapping(5);
-            ///
-            /// assert_eq!(x.pow(4).0, 113);
-            /// ```
-            #[inline]
-            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
-            pub fn pow(self, exp: u32) -> Self {
-                Wrapping(self.0.wrapping_pow(exp))
+            doc_comment! {
+                concat!("Converts `self` to little endian from the target's endianness.
+
+On little endian this is a no-op. On big endian the bytes are
+swapped.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(0x1A", stringify!($t), ");
+
+if cfg!(target_endian = \"little\") {
+    assert_eq!(n.to_le(), n)
+} else {
+    assert_eq!(n.to_le(), n.swap_bytes())
+}
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn to_le(self) -> Self {
+                    Wrapping(self.0.to_le())
+                }
+            }
+
+        doc_comment! {
+            concat!("Raises self to the power of `exp`, using exponentiation by squaring.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert_eq!(Wrapping(3", stringify!($t), ").pow(4), Wrapping(81));
+```
+
+Results that are too large are wrapped:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert_eq!(Wrapping(3i8).pow(5), Wrapping(-13));
+assert_eq!(Wrapping(3i8).pow(6), Wrapping(-39));
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn pow(self, exp: u32) -> Self {
+                    Wrapping(self.0.wrapping_pow(exp))
+                }
             }
         }
     )*)
@@ -630,6 +688,211 @@ macro_rules! wrapping_int_impl {
 
 wrapping_int_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
 
+macro_rules! wrapping_int_impl_signed {
+    ($($t:ty)*) => ($(
+        impl Wrapping<$t> {
+            doc_comment! {
+                concat!("Returns the number of leading zeros in the binary representation of `self`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(", stringify!($t), "::max_value()) >> 2;
+
+assert_eq!(n.leading_zeros(), 3);
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn leading_zeros(self) -> u32 {
+                    self.0.leading_zeros()
+                }
+            }
+
+            doc_comment! {
+                concat!("Computes the absolute value of `self`, wrapping around at
+the boundary of the type.
+
+The only case where such wrapping can occur is when one takes the absolute value of the negative
+minimal value for the type this is a positive value that is too large to represent in the type. In
+such a case, this function returns `MIN` itself.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert_eq!(Wrapping(100", stringify!($t), ").abs(), Wrapping(100));
+assert_eq!(Wrapping(-100", stringify!($t), ").abs(), Wrapping(100));
+assert_eq!(Wrapping(", stringify!($t), "::min_value()).abs(), Wrapping(", stringify!($t),
+"::min_value()));
+assert_eq!(Wrapping(-128i8).abs().0 as u8, 128u8);
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn abs(self) -> Wrapping<$t> {
+                    Wrapping(self.0.wrapping_abs())
+                }
+            }
+
+            doc_comment! {
+                concat!("Returns a number representing sign of `self`.
+
+ - `0` if the number is zero
+ - `1` if the number is positive
+ - `-1` if the number is negative
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert_eq!(Wrapping(10", stringify!($t), ").signum(), Wrapping(1));
+assert_eq!(Wrapping(0", stringify!($t), ").signum(), Wrapping(0));
+assert_eq!(Wrapping(-10", stringify!($t), ").signum(), Wrapping(-1));
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn signum(self) -> Wrapping<$t> {
+                    Wrapping(self.0.signum())
+                }
+            }
+
+            doc_comment! {
+                concat!("Returns `true` if `self` is positive and `false` if the number is zero or
+negative.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert!(Wrapping(10", stringify!($t), ").is_positive());
+assert!(!Wrapping(-10", stringify!($t), ").is_positive());
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn is_positive(self) -> bool {
+                    self.0.is_positive()
+                }
+            }
+
+            doc_comment! {
+                concat!("Returns `true` if `self` is negative and `false` if the number is zero or
+positive.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert!(Wrapping(-10", stringify!($t), ").is_negative());
+assert!(!Wrapping(10", stringify!($t), ").is_negative());
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn is_negative(self) -> bool {
+                    self.0.is_negative()
+                }
+            }
+        }
+    )*)
+}
+
+wrapping_int_impl_signed! { isize i8 i16 i32 i64 i128 }
+
+macro_rules! wrapping_int_impl_unsigned {
+    ($($t:ty)*) => ($(
+        impl Wrapping<$t> {
+            doc_comment! {
+                concat!("Returns the number of leading zeros in the binary representation of `self`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+let n = Wrapping(", stringify!($t), "::max_value()) >> 2;
+
+assert_eq!(n.leading_zeros(), 2);
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn leading_zeros(self) -> u32 {
+                    self.0.leading_zeros()
+                }
+            }
+
+            doc_comment! {
+                concat!("Returns `true` if and only if `self == 2^k` for some `k`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_int_impl)]
+use std::num::Wrapping;
+
+assert!(Wrapping(16", stringify!($t), ").is_power_of_two());
+assert!(!Wrapping(10", stringify!($t), ").is_power_of_two());
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
+                pub fn is_power_of_two(self) -> bool {
+                    self.0.is_power_of_two()
+                }
+            }
+
+            doc_comment! {
+                concat!("Returns the smallest power of two greater than or equal to `self`.
+
+When return value overflows (i.e. `self > (1 << (N-1))` for type
+`uN`), overflows to `2^N = 0`.
+
+# Examples
+
+Basic usage:
+
+```
+#![feature(wrapping_next_power_of_two)]
+use std::num::Wrapping;
+
+assert_eq!(Wrapping(2", stringify!($t), ").next_power_of_two(), Wrapping(2));
+assert_eq!(Wrapping(3", stringify!($t), ").next_power_of_two(), Wrapping(4));
+assert_eq!(Wrapping(200_u8).next_power_of_two(), Wrapping(0));
+```"),
+                #[inline]
+                #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
+                           reason = "needs decision on wrapping behaviour")]
+                pub fn next_power_of_two(self) -> Self {
+                    Wrapping(self.0.wrapping_next_power_of_two())
+                }
+            }
+        }
+    )*)
+}
+
+wrapping_int_impl_unsigned! { usize u8 u16 u32 u64 u128 }
 
 mod shift_max {
     #![allow(non_upper_case_globals)]
@@ -656,11 +919,13 @@ mod shift_max {
     pub const i16: u32 = (1 << 4) - 1;
     pub const i32: u32 = (1 << 5) - 1;
     pub const i64: u32 = (1 << 6) - 1;
+    pub const i128: u32 = (1 << 7) - 1;
     pub use self::platform::isize;
 
     pub const u8: u32 = i8;
     pub const u16: u32 = i16;
     pub const u32: u32 = i32;
     pub const u64: u32 = i64;
+    pub const u128: u32 = i128;
     pub use self::platform::usize;
 }