Rollup merge of #129592 - saethlin:core-cfg-test, r=tgross35

Remove cfg(test) from library/core

The diff here is very small with the ignore whitespace option.

`core` doesn't/can't have unit tests. All of its tests are just modules under `tests/`, so it has no use for `cfg(test)`, because the entire contents of `library/core/src` are only ever compiled with that cfg off, and the entire contents of `library/core/tests` are only ever compiled with that cfg on.

You can tell this is what's happening because we had `#[cfg(test)]` on a module declaration that has no source file.

I also deleted the extra `mod tests {` layer of nesting; there's no need to mention again in the module path that this is a module of tests. This exposes a name collision between the `u128` module of tests and `core::u128`. Fixed that by using `<u128>::MAX` like is done in the `check!` macro, which is what avoids this name ambiguity for the other types.

5 files changed, 649 insertions, 659 deletions

diff --git a/library/core/src/error.rs b/library/core/src/error.rs
index 6cc91849e1d..cac00b37d1f 100644
--- a/library/core/src/error.rs
+++ b/library/core/src/error.rs
@@ -1,9 +1,6 @@
 #![doc = include_str!("error.md")]
 #![stable(feature = "error_in_core", since = "1.81.0")]
 
-#[cfg(test)]
-mod tests;
-
 use crate::any::TypeId;
 use crate::fmt::{Debug, Display, Formatter, Result};
 
diff --git a/library/core/tests/lib.rs b/library/core/tests/lib.rs
index 073429c7628..c205f028dd3 100644
--- a/library/core/tests/lib.rs
+++ b/library/core/tests/lib.rs
@@ -141,7 +141,6 @@ mod intrinsics;
 mod io;
 mod iter;
 mod lazy;
-#[cfg(test)]
 mod macros;
 mod manually_drop;
 mod mem;
diff --git a/library/core/tests/num/int_macros.rs b/library/core/tests/num/int_macros.rs
index 165d9a29617..7cd3b54e3f3 100644
--- a/library/core/tests/num/int_macros.rs
+++ b/library/core/tests/num/int_macros.rs
@@ -1,427 +1,424 @@
 macro_rules! int_module {
     ($T:ident) => {
-        #[cfg(test)]
-        mod tests {
-            use core::ops::{BitAnd, BitOr, BitXor, Not, Shl, Shr};
-            use core::$T::*;
-
-            use crate::num;
-
-            #[test]
-            fn test_overflows() {
-                assert!(MAX > 0);
-                assert!(MIN <= 0);
-                assert_eq!(MIN + MAX + 1, 0);
-            }
+        use core::ops::{BitAnd, BitOr, BitXor, Not, Shl, Shr};
+        use core::$T::*;
 
-            #[test]
-            fn test_num() {
-                num::test_num(10 as $T, 2 as $T);
-            }
+        use crate::num;
 
-            #[test]
-            fn test_rem_euclid() {
-                assert_eq!((-1 as $T).rem_euclid(MIN), MAX);
-            }
+        #[test]
+        fn test_overflows() {
+            assert!(MAX > 0);
+            assert!(MIN <= 0);
+            assert_eq!(MIN + MAX + 1, 0);
+        }
 
-            #[test]
-            pub fn test_abs() {
-                assert_eq!((1 as $T).abs(), 1 as $T);
-                assert_eq!((0 as $T).abs(), 0 as $T);
-                assert_eq!((-1 as $T).abs(), 1 as $T);
-            }
+        #[test]
+        fn test_num() {
+            num::test_num(10 as $T, 2 as $T);
+        }
 
-            #[test]
-            fn test_signum() {
-                assert_eq!((1 as $T).signum(), 1 as $T);
-                assert_eq!((0 as $T).signum(), 0 as $T);
-                assert_eq!((-0 as $T).signum(), 0 as $T);
-                assert_eq!((-1 as $T).signum(), -1 as $T);
-            }
+        #[test]
+        fn test_rem_euclid() {
+            assert_eq!((-1 as $T).rem_euclid(MIN), MAX);
+        }
 
-            #[test]
-            fn test_is_positive() {
-                assert!((1 as $T).is_positive());
-                assert!(!(0 as $T).is_positive());
-                assert!(!(-0 as $T).is_positive());
-                assert!(!(-1 as $T).is_positive());
-            }
+        #[test]
+        pub fn test_abs() {
+            assert_eq!((1 as $T).abs(), 1 as $T);
+            assert_eq!((0 as $T).abs(), 0 as $T);
+            assert_eq!((-1 as $T).abs(), 1 as $T);
+        }
 
-            #[test]
-            fn test_is_negative() {
-                assert!(!(1 as $T).is_negative());
-                assert!(!(0 as $T).is_negative());
-                assert!(!(-0 as $T).is_negative());
-                assert!((-1 as $T).is_negative());
-            }
+        #[test]
+        fn test_signum() {
+            assert_eq!((1 as $T).signum(), 1 as $T);
+            assert_eq!((0 as $T).signum(), 0 as $T);
+            assert_eq!((-0 as $T).signum(), 0 as $T);
+            assert_eq!((-1 as $T).signum(), -1 as $T);
+        }
 
-            #[test]
-            fn test_bitwise_operators() {
-                assert_eq!(0b1110 as $T, (0b1100 as $T).bitor(0b1010 as $T));
-                assert_eq!(0b1000 as $T, (0b1100 as $T).bitand(0b1010 as $T));
-                assert_eq!(0b0110 as $T, (0b1100 as $T).bitxor(0b1010 as $T));
-                assert_eq!(0b1110 as $T, (0b0111 as $T).shl(1));
-                assert_eq!(0b0111 as $T, (0b1110 as $T).shr(1));
-                assert_eq!(-(0b11 as $T) - (1 as $T), (0b11 as $T).not());
-            }
+        #[test]
+        fn test_is_positive() {
+            assert!((1 as $T).is_positive());
+            assert!(!(0 as $T).is_positive());
+            assert!(!(-0 as $T).is_positive());
+            assert!(!(-1 as $T).is_positive());
+        }
 
-            const A: $T = 0b0101100;
-            const B: $T = 0b0100001;
-            const C: $T = 0b1111001;
+        #[test]
+        fn test_is_negative() {
+            assert!(!(1 as $T).is_negative());
+            assert!(!(0 as $T).is_negative());
+            assert!(!(-0 as $T).is_negative());
+            assert!((-1 as $T).is_negative());
+        }
 
-            const _0: $T = 0;
-            const _1: $T = !0;
+        #[test]
+        fn test_bitwise_operators() {
+            assert_eq!(0b1110 as $T, (0b1100 as $T).bitor(0b1010 as $T));
+            assert_eq!(0b1000 as $T, (0b1100 as $T).bitand(0b1010 as $T));
+            assert_eq!(0b0110 as $T, (0b1100 as $T).bitxor(0b1010 as $T));
+            assert_eq!(0b1110 as $T, (0b0111 as $T).shl(1));
+            assert_eq!(0b0111 as $T, (0b1110 as $T).shr(1));
+            assert_eq!(-(0b11 as $T) - (1 as $T), (0b11 as $T).not());
+        }
 
-            #[test]
-            fn test_count_ones() {
-                assert_eq!(A.count_ones(), 3);
-                assert_eq!(B.count_ones(), 2);
-                assert_eq!(C.count_ones(), 5);
-            }
+        const A: $T = 0b0101100;
+        const B: $T = 0b0100001;
+        const C: $T = 0b1111001;
 
-            #[test]
-            fn test_count_zeros() {
-                assert_eq!(A.count_zeros(), $T::BITS - 3);
-                assert_eq!(B.count_zeros(), $T::BITS - 2);
-                assert_eq!(C.count_zeros(), $T::BITS - 5);
-            }
+        const _0: $T = 0;
+        const _1: $T = !0;
 
-            #[test]
-            fn test_leading_trailing_ones() {
-                let a: $T = 0b0101_1111;
-                assert_eq!(a.trailing_ones(), 5);
-                assert_eq!((!a).leading_ones(), $T::BITS - 7);
+        #[test]
+        fn test_count_ones() {
+            assert_eq!(A.count_ones(), 3);
+            assert_eq!(B.count_ones(), 2);
+            assert_eq!(C.count_ones(), 5);
+        }
 
-                assert_eq!(a.reverse_bits().leading_ones(), 5);
+        #[test]
+        fn test_count_zeros() {
+            assert_eq!(A.count_zeros(), $T::BITS - 3);
+            assert_eq!(B.count_zeros(), $T::BITS - 2);
+            assert_eq!(C.count_zeros(), $T::BITS - 5);
+        }
 
-                assert_eq!(_1.leading_ones(), $T::BITS);
-                assert_eq!(_1.trailing_ones(), $T::BITS);
+        #[test]
+        fn test_leading_trailing_ones() {
+            let a: $T = 0b0101_1111;
+            assert_eq!(a.trailing_ones(), 5);
+            assert_eq!((!a).leading_ones(), $T::BITS - 7);
 
-                assert_eq!((_1 << 1).trailing_ones(), 0);
-                assert_eq!(MAX.leading_ones(), 0);
+            assert_eq!(a.reverse_bits().leading_ones(), 5);
 
-                assert_eq!((_1 << 1).leading_ones(), $T::BITS - 1);
-                assert_eq!(MAX.trailing_ones(), $T::BITS - 1);
+            assert_eq!(_1.leading_ones(), $T::BITS);
+            assert_eq!(_1.trailing_ones(), $T::BITS);
 
-                assert_eq!(_0.leading_ones(), 0);
-                assert_eq!(_0.trailing_ones(), 0);
+            assert_eq!((_1 << 1).trailing_ones(), 0);
+            assert_eq!(MAX.leading_ones(), 0);
 
-                let x: $T = 0b0010_1100;
-                assert_eq!(x.leading_ones(), 0);
-                assert_eq!(x.trailing_ones(), 0);
-            }
+            assert_eq!((_1 << 1).leading_ones(), $T::BITS - 1);
+            assert_eq!(MAX.trailing_ones(), $T::BITS - 1);
 
-            #[test]
-            fn test_rotate() {
-                assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
-                assert_eq!(B.rotate_left(3).rotate_left(2).rotate_right(5), B);
-                assert_eq!(C.rotate_left(6).rotate_right(2).rotate_right(4), C);
-
-                // Rotating these should make no difference
-                //
-                // We test using 124 bits because to ensure that overlong bit shifts do
-                // not cause undefined behaviour. See #10183.
-                assert_eq!(_0.rotate_left(124), _0);
-                assert_eq!(_1.rotate_left(124), _1);
-                assert_eq!(_0.rotate_right(124), _0);
-                assert_eq!(_1.rotate_right(124), _1);
-
-                // Rotating by 0 should have no effect
-                assert_eq!(A.rotate_left(0), A);
-                assert_eq!(B.rotate_left(0), B);
-                assert_eq!(C.rotate_left(0), C);
-                // Rotating by a multiple of word size should also have no effect
-                assert_eq!(A.rotate_left(128), A);
-                assert_eq!(B.rotate_left(128), B);
-                assert_eq!(C.rotate_left(128), C);
-            }
+            assert_eq!(_0.leading_ones(), 0);
+            assert_eq!(_0.trailing_ones(), 0);
 
-            #[test]
-            fn test_swap_bytes() {
-                assert_eq!(A.swap_bytes().swap_bytes(), A);
-                assert_eq!(B.swap_bytes().swap_bytes(), B);
-                assert_eq!(C.swap_bytes().swap_bytes(), C);
+            let x: $T = 0b0010_1100;
+            assert_eq!(x.leading_ones(), 0);
+            assert_eq!(x.trailing_ones(), 0);
+        }
 
-                // Swapping these should make no difference
-                assert_eq!(_0.swap_bytes(), _0);
-                assert_eq!(_1.swap_bytes(), _1);
-            }
+        #[test]
+        fn test_rotate() {
+            assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
+            assert_eq!(B.rotate_left(3).rotate_left(2).rotate_right(5), B);
+            assert_eq!(C.rotate_left(6).rotate_right(2).rotate_right(4), C);
+
+            // Rotating these should make no difference
+            //
+            // We test using 124 bits because to ensure that overlong bit shifts do
+            // not cause undefined behaviour. See #10183.
+            assert_eq!(_0.rotate_left(124), _0);
+            assert_eq!(_1.rotate_left(124), _1);
+            assert_eq!(_0.rotate_right(124), _0);
+            assert_eq!(_1.rotate_right(124), _1);
+
+            // Rotating by 0 should have no effect
+            assert_eq!(A.rotate_left(0), A);
+            assert_eq!(B.rotate_left(0), B);
+            assert_eq!(C.rotate_left(0), C);
+            // Rotating by a multiple of word size should also have no effect
+            assert_eq!(A.rotate_left(128), A);
+            assert_eq!(B.rotate_left(128), B);
+            assert_eq!(C.rotate_left(128), C);
+        }
 
-            #[test]
-            fn test_le() {
-                assert_eq!($T::from_le(A.to_le()), A);
-                assert_eq!($T::from_le(B.to_le()), B);
-                assert_eq!($T::from_le(C.to_le()), C);
-                assert_eq!($T::from_le(_0), _0);
-                assert_eq!($T::from_le(_1), _1);
-                assert_eq!(_0.to_le(), _0);
-                assert_eq!(_1.to_le(), _1);
-            }
+        #[test]
+        fn test_swap_bytes() {
+            assert_eq!(A.swap_bytes().swap_bytes(), A);
+            assert_eq!(B.swap_bytes().swap_bytes(), B);
+            assert_eq!(C.swap_bytes().swap_bytes(), C);
 
-            #[test]
-            fn test_be() {
-                assert_eq!($T::from_be(A.to_be()), A);
-                assert_eq!($T::from_be(B.to_be()), B);
-                assert_eq!($T::from_be(C.to_be()), C);
-                assert_eq!($T::from_be(_0), _0);
-                assert_eq!($T::from_be(_1), _1);
-                assert_eq!(_0.to_be(), _0);
-                assert_eq!(_1.to_be(), _1);
-            }
+            // Swapping these should make no difference
+            assert_eq!(_0.swap_bytes(), _0);
+            assert_eq!(_1.swap_bytes(), _1);
+        }
 
-            #[test]
-            fn test_signed_checked_div() {
-                assert_eq!((10 as $T).checked_div(2), Some(5));
-                assert_eq!((5 as $T).checked_div(0), None);
-                assert_eq!(isize::MIN.checked_div(-1), None);
-            }
+        #[test]
+        fn test_le() {
+            assert_eq!($T::from_le(A.to_le()), A);
+            assert_eq!($T::from_le(B.to_le()), B);
+            assert_eq!($T::from_le(C.to_le()), C);
+            assert_eq!($T::from_le(_0), _0);
+            assert_eq!($T::from_le(_1), _1);
+            assert_eq!(_0.to_le(), _0);
+            assert_eq!(_1.to_le(), _1);
+        }
 
-            #[test]
-            fn test_saturating_abs() {
-                assert_eq!((0 as $T).saturating_abs(), 0);
-                assert_eq!((123 as $T).saturating_abs(), 123);
-                assert_eq!((-123 as $T).saturating_abs(), 123);
-                assert_eq!((MAX - 2).saturating_abs(), MAX - 2);
-                assert_eq!((MAX - 1).saturating_abs(), MAX - 1);
-                assert_eq!(MAX.saturating_abs(), MAX);
-                assert_eq!((MIN + 2).saturating_abs(), MAX - 1);
-                assert_eq!((MIN + 1).saturating_abs(), MAX);
-                assert_eq!(MIN.saturating_abs(), MAX);
-            }
+        #[test]
+        fn test_be() {
+            assert_eq!($T::from_be(A.to_be()), A);
+            assert_eq!($T::from_be(B.to_be()), B);
+            assert_eq!($T::from_be(C.to_be()), C);
+            assert_eq!($T::from_be(_0), _0);
+            assert_eq!($T::from_be(_1), _1);
+            assert_eq!(_0.to_be(), _0);
+            assert_eq!(_1.to_be(), _1);
+        }
 
-            #[test]
-            fn test_saturating_neg() {
-                assert_eq!((0 as $T).saturating_neg(), 0);
-                assert_eq!((123 as $T).saturating_neg(), -123);
-                assert_eq!((-123 as $T).saturating_neg(), 123);
-                assert_eq!((MAX - 2).saturating_neg(), MIN + 3);
-                assert_eq!((MAX - 1).saturating_neg(), MIN + 2);
-                assert_eq!(MAX.saturating_neg(), MIN + 1);
-                assert_eq!((MIN + 2).saturating_neg(), MAX - 1);
-                assert_eq!((MIN + 1).saturating_neg(), MAX);
-                assert_eq!(MIN.saturating_neg(), MAX);
-            }
+        #[test]
+        fn test_signed_checked_div() {
+            assert_eq!((10 as $T).checked_div(2), Some(5));
+            assert_eq!((5 as $T).checked_div(0), None);
+            assert_eq!(isize::MIN.checked_div(-1), None);
+        }
 
-            #[test]
-            fn test_from_str() {
-                fn from_str<T: std::str::FromStr>(t: &str) -> Option<T> {
-                    std::str::FromStr::from_str(t).ok()
-                }
-                assert_eq!(from_str::<$T>("0"), Some(0 as $T));
-                assert_eq!(from_str::<$T>("3"), Some(3 as $T));
-                assert_eq!(from_str::<$T>("10"), Some(10 as $T));
-                assert_eq!(from_str::<i32>("123456789"), Some(123456789 as i32));
-                assert_eq!(from_str::<$T>("00100"), Some(100 as $T));
-
-                assert_eq!(from_str::<$T>("-1"), Some(-1 as $T));
-                assert_eq!(from_str::<$T>("-3"), Some(-3 as $T));
-                assert_eq!(from_str::<$T>("-10"), Some(-10 as $T));
-                assert_eq!(from_str::<i32>("-123456789"), Some(-123456789 as i32));
-                assert_eq!(from_str::<$T>("-00100"), Some(-100 as $T));
-
-                assert_eq!(from_str::<$T>(""), None);
-                assert_eq!(from_str::<$T>(" "), None);
-                assert_eq!(from_str::<$T>("x"), None);
-            }
+        #[test]
+        fn test_saturating_abs() {
+            assert_eq!((0 as $T).saturating_abs(), 0);
+            assert_eq!((123 as $T).saturating_abs(), 123);
+            assert_eq!((-123 as $T).saturating_abs(), 123);
+            assert_eq!((MAX - 2).saturating_abs(), MAX - 2);
+            assert_eq!((MAX - 1).saturating_abs(), MAX - 1);
+            assert_eq!(MAX.saturating_abs(), MAX);
+            assert_eq!((MIN + 2).saturating_abs(), MAX - 1);
+            assert_eq!((MIN + 1).saturating_abs(), MAX);
+            assert_eq!(MIN.saturating_abs(), MAX);
+        }
 
-            #[test]
-            fn test_from_str_radix() {
-                assert_eq!($T::from_str_radix("123", 10), Ok(123 as $T));
-                assert_eq!($T::from_str_radix("1001", 2), Ok(9 as $T));
-                assert_eq!($T::from_str_radix("123", 8), Ok(83 as $T));
-                assert_eq!(i32::from_str_radix("123", 16), Ok(291 as i32));
-                assert_eq!(i32::from_str_radix("ffff", 16), Ok(65535 as i32));
-                assert_eq!(i32::from_str_radix("FFFF", 16), Ok(65535 as i32));
-                assert_eq!($T::from_str_radix("z", 36), Ok(35 as $T));
-                assert_eq!($T::from_str_radix("Z", 36), Ok(35 as $T));
-
-                assert_eq!($T::from_str_radix("-123", 10), Ok(-123 as $T));
-                assert_eq!($T::from_str_radix("-1001", 2), Ok(-9 as $T));
-                assert_eq!($T::from_str_radix("-123", 8), Ok(-83 as $T));
-                assert_eq!(i32::from_str_radix("-123", 16), Ok(-291 as i32));
-                assert_eq!(i32::from_str_radix("-ffff", 16), Ok(-65535 as i32));
-                assert_eq!(i32::from_str_radix("-FFFF", 16), Ok(-65535 as i32));
-                assert_eq!($T::from_str_radix("-z", 36), Ok(-35 as $T));
-                assert_eq!($T::from_str_radix("-Z", 36), Ok(-35 as $T));
-
-                assert_eq!($T::from_str_radix("Z", 35).ok(), None::<$T>);
-                assert_eq!($T::from_str_radix("-9", 2).ok(), None::<$T>);
-            }
+        #[test]
+        fn test_saturating_neg() {
+            assert_eq!((0 as $T).saturating_neg(), 0);
+            assert_eq!((123 as $T).saturating_neg(), -123);
+            assert_eq!((-123 as $T).saturating_neg(), 123);
+            assert_eq!((MAX - 2).saturating_neg(), MIN + 3);
+            assert_eq!((MAX - 1).saturating_neg(), MIN + 2);
+            assert_eq!(MAX.saturating_neg(), MIN + 1);
+            assert_eq!((MIN + 2).saturating_neg(), MAX - 1);
+            assert_eq!((MIN + 1).saturating_neg(), MAX);
+            assert_eq!(MIN.saturating_neg(), MAX);
+        }
 
-            #[test]
-            fn test_pow() {
-                let mut r = 2 as $T;
-                assert_eq!(r.pow(2), 4 as $T);
-                assert_eq!(r.pow(0), 1 as $T);
-                assert_eq!(r.wrapping_pow(2), 4 as $T);
-                assert_eq!(r.wrapping_pow(0), 1 as $T);
-                assert_eq!(r.checked_pow(2), Some(4 as $T));
-                assert_eq!(r.checked_pow(0), Some(1 as $T));
-                assert_eq!(r.overflowing_pow(2), (4 as $T, false));
-                assert_eq!(r.overflowing_pow(0), (1 as $T, false));
-                assert_eq!(r.saturating_pow(2), 4 as $T);
-                assert_eq!(r.saturating_pow(0), 1 as $T);
-
-                r = MAX;
-                // use `^` to represent .pow() with no overflow.
-                // if itest::MAX == 2^j-1, then itest is a `j` bit int,
-                // so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
-                // thussaturating_pow the overflowing result is exactly 1.
-                assert_eq!(r.wrapping_pow(2), 1 as $T);
-                assert_eq!(r.checked_pow(2), None);
-                assert_eq!(r.overflowing_pow(2), (1 as $T, true));
-                assert_eq!(r.saturating_pow(2), MAX);
-                //test for negative exponent.
-                r = -2 as $T;
-                assert_eq!(r.pow(2), 4 as $T);
-                assert_eq!(r.pow(3), -8 as $T);
-                assert_eq!(r.pow(0), 1 as $T);
-                assert_eq!(r.wrapping_pow(2), 4 as $T);
-                assert_eq!(r.wrapping_pow(3), -8 as $T);
-                assert_eq!(r.wrapping_pow(0), 1 as $T);
-                assert_eq!(r.checked_pow(2), Some(4 as $T));
-                assert_eq!(r.checked_pow(3), Some(-8 as $T));
-                assert_eq!(r.checked_pow(0), Some(1 as $T));
-                assert_eq!(r.overflowing_pow(2), (4 as $T, false));
-                assert_eq!(r.overflowing_pow(3), (-8 as $T, false));
-                assert_eq!(r.overflowing_pow(0), (1 as $T, false));
-                assert_eq!(r.saturating_pow(2), 4 as $T);
-                assert_eq!(r.saturating_pow(3), -8 as $T);
-                assert_eq!(r.saturating_pow(0), 1 as $T);
+        #[test]
+        fn test_from_str() {
+            fn from_str<T: std::str::FromStr>(t: &str) -> Option<T> {
+                std::str::FromStr::from_str(t).ok()
             }
+            assert_eq!(from_str::<$T>("0"), Some(0 as $T));
+            assert_eq!(from_str::<$T>("3"), Some(3 as $T));
+            assert_eq!(from_str::<$T>("10"), Some(10 as $T));
+            assert_eq!(from_str::<i32>("123456789"), Some(123456789 as i32));
+            assert_eq!(from_str::<$T>("00100"), Some(100 as $T));
+
+            assert_eq!(from_str::<$T>("-1"), Some(-1 as $T));
+            assert_eq!(from_str::<$T>("-3"), Some(-3 as $T));
+            assert_eq!(from_str::<$T>("-10"), Some(-10 as $T));
+            assert_eq!(from_str::<i32>("-123456789"), Some(-123456789 as i32));
+            assert_eq!(from_str::<$T>("-00100"), Some(-100 as $T));
+
+            assert_eq!(from_str::<$T>(""), None);
+            assert_eq!(from_str::<$T>(" "), None);
+            assert_eq!(from_str::<$T>("x"), None);
+        }
 
-            #[test]
-            fn test_isqrt() {
-                assert_eq!($T::MIN.checked_isqrt(), None);
-                assert_eq!((-1 as $T).checked_isqrt(), None);
-                assert_eq!((0 as $T).isqrt(), 0 as $T);
-                assert_eq!((1 as $T).isqrt(), 1 as $T);
-                assert_eq!((2 as $T).isqrt(), 1 as $T);
-                assert_eq!((99 as $T).isqrt(), 9 as $T);
-                assert_eq!((100 as $T).isqrt(), 10 as $T);
-            }
+        #[test]
+        fn test_from_str_radix() {
+            assert_eq!($T::from_str_radix("123", 10), Ok(123 as $T));
+            assert_eq!($T::from_str_radix("1001", 2), Ok(9 as $T));
+            assert_eq!($T::from_str_radix("123", 8), Ok(83 as $T));
+            assert_eq!(i32::from_str_radix("123", 16), Ok(291 as i32));
+            assert_eq!(i32::from_str_radix("ffff", 16), Ok(65535 as i32));
+            assert_eq!(i32::from_str_radix("FFFF", 16), Ok(65535 as i32));
+            assert_eq!($T::from_str_radix("z", 36), Ok(35 as $T));
+            assert_eq!($T::from_str_radix("Z", 36), Ok(35 as $T));
+
+            assert_eq!($T::from_str_radix("-123", 10), Ok(-123 as $T));
+            assert_eq!($T::from_str_radix("-1001", 2), Ok(-9 as $T));
+            assert_eq!($T::from_str_radix("-123", 8), Ok(-83 as $T));
+            assert_eq!(i32::from_str_radix("-123", 16), Ok(-291 as i32));
+            assert_eq!(i32::from_str_radix("-ffff", 16), Ok(-65535 as i32));
+            assert_eq!(i32::from_str_radix("-FFFF", 16), Ok(-65535 as i32));
+            assert_eq!($T::from_str_radix("-z", 36), Ok(-35 as $T));
+            assert_eq!($T::from_str_radix("-Z", 36), Ok(-35 as $T));
+
+            assert_eq!($T::from_str_radix("Z", 35).ok(), None::<$T>);
+            assert_eq!($T::from_str_radix("-9", 2).ok(), None::<$T>);
+        }
 
-            #[cfg(not(miri))] // Miri is too slow
-            #[test]
-            fn test_lots_of_isqrt() {
-                let n_max: $T = (1024 * 1024).min($T::MAX as u128) as $T;
-                for n in 0..=n_max {
-                    let isqrt: $T = n.isqrt();
-
-                    assert!(isqrt.pow(2) <= n);
-                    let (square, overflow) = (isqrt + 1).overflowing_pow(2);
-                    assert!(overflow || square > n);
-                }
-
-                for n in ($T::MAX - 127)..=$T::MAX {
-                    let isqrt: $T = n.isqrt();
-
-                    assert!(isqrt.pow(2) <= n);
-                    let (square, overflow) = (isqrt + 1).overflowing_pow(2);
-                    assert!(overflow || square > n);
-                }
-            }
+        #[test]
+        fn test_pow() {
+            let mut r = 2 as $T;
+            assert_eq!(r.pow(2), 4 as $T);
+            assert_eq!(r.pow(0), 1 as $T);
+            assert_eq!(r.wrapping_pow(2), 4 as $T);
+            assert_eq!(r.wrapping_pow(0), 1 as $T);
+            assert_eq!(r.checked_pow(2), Some(4 as $T));
+            assert_eq!(r.checked_pow(0), Some(1 as $T));
+            assert_eq!(r.overflowing_pow(2), (4 as $T, false));
+            assert_eq!(r.overflowing_pow(0), (1 as $T, false));
+            assert_eq!(r.saturating_pow(2), 4 as $T);
+            assert_eq!(r.saturating_pow(0), 1 as $T);
+
+            r = MAX;
+            // use `^` to represent .pow() with no overflow.
+            // if itest::MAX == 2^j-1, then itest is a `j` bit int,
+            // so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
+            // thussaturating_pow the overflowing result is exactly 1.
+            assert_eq!(r.wrapping_pow(2), 1 as $T);
+            assert_eq!(r.checked_pow(2), None);
+            assert_eq!(r.overflowing_pow(2), (1 as $T, true));
+            assert_eq!(r.saturating_pow(2), MAX);
+            //test for negative exponent.
+            r = -2 as $T;
+            assert_eq!(r.pow(2), 4 as $T);
+            assert_eq!(r.pow(3), -8 as $T);
+            assert_eq!(r.pow(0), 1 as $T);
+            assert_eq!(r.wrapping_pow(2), 4 as $T);
+            assert_eq!(r.wrapping_pow(3), -8 as $T);
+            assert_eq!(r.wrapping_pow(0), 1 as $T);
+            assert_eq!(r.checked_pow(2), Some(4 as $T));
+            assert_eq!(r.checked_pow(3), Some(-8 as $T));
+            assert_eq!(r.checked_pow(0), Some(1 as $T));
+            assert_eq!(r.overflowing_pow(2), (4 as $T, false));
+            assert_eq!(r.overflowing_pow(3), (-8 as $T, false));
+            assert_eq!(r.overflowing_pow(0), (1 as $T, false));
+            assert_eq!(r.saturating_pow(2), 4 as $T);
+            assert_eq!(r.saturating_pow(3), -8 as $T);
+            assert_eq!(r.saturating_pow(0), 1 as $T);
+        }
 
-            #[test]
-            fn test_div_floor() {
-                let a: $T = 8;
-                let b = 3;
-                assert_eq!(a.div_floor(b), 2);
-                assert_eq!(a.div_floor(-b), -3);
-                assert_eq!((-a).div_floor(b), -3);
-                assert_eq!((-a).div_floor(-b), 2);
-            }
+        #[test]
+        fn test_isqrt() {
+            assert_eq!($T::MIN.checked_isqrt(), None);
+            assert_eq!((-1 as $T).checked_isqrt(), None);
+            assert_eq!((0 as $T).isqrt(), 0 as $T);
+            assert_eq!((1 as $T).isqrt(), 1 as $T);
+            assert_eq!((2 as $T).isqrt(), 1 as $T);
+            assert_eq!((99 as $T).isqrt(), 9 as $T);
+            assert_eq!((100 as $T).isqrt(), 10 as $T);
+        }
 
-            #[test]
-            fn test_div_ceil() {
-                let a: $T = 8;
-                let b = 3;
-                assert_eq!(a.div_ceil(b), 3);
-                assert_eq!(a.div_ceil(-b), -2);
-                assert_eq!((-a).div_ceil(b), -2);
-                assert_eq!((-a).div_ceil(-b), 3);
-            }
+        #[cfg(not(miri))] // Miri is too slow
+        #[test]
+        fn test_lots_of_isqrt() {
+            let n_max: $T = (1024 * 1024).min($T::MAX as u128) as $T;
+            for n in 0..=n_max {
+                let isqrt: $T = n.isqrt();
 
-            #[test]
-            fn test_next_multiple_of() {
-                assert_eq!((16 as $T).next_multiple_of(8), 16);
-                assert_eq!((23 as $T).next_multiple_of(8), 24);
-                assert_eq!((16 as $T).next_multiple_of(-8), 16);
-                assert_eq!((23 as $T).next_multiple_of(-8), 16);
-                assert_eq!((-16 as $T).next_multiple_of(8), -16);
-                assert_eq!((-23 as $T).next_multiple_of(8), -16);
-                assert_eq!((-16 as $T).next_multiple_of(-8), -16);
-                assert_eq!((-23 as $T).next_multiple_of(-8), -24);
-                assert_eq!(MIN.next_multiple_of(-1), MIN);
+                assert!(isqrt.pow(2) <= n);
+                let (square, overflow) = (isqrt + 1).overflowing_pow(2);
+                assert!(overflow || square > n);
             }
 
-            #[test]
-            fn test_checked_next_multiple_of() {
-                assert_eq!((16 as $T).checked_next_multiple_of(8), Some(16));
-                assert_eq!((23 as $T).checked_next_multiple_of(8), Some(24));
-                assert_eq!((16 as $T).checked_next_multiple_of(-8), Some(16));
-                assert_eq!((23 as $T).checked_next_multiple_of(-8), Some(16));
-                assert_eq!((-16 as $T).checked_next_multiple_of(8), Some(-16));
-                assert_eq!((-23 as $T).checked_next_multiple_of(8), Some(-16));
-                assert_eq!((-16 as $T).checked_next_multiple_of(-8), Some(-16));
-                assert_eq!((-23 as $T).checked_next_multiple_of(-8), Some(-24));
-                assert_eq!((1 as $T).checked_next_multiple_of(0), None);
-                assert_eq!(MAX.checked_next_multiple_of(2), None);
-                assert_eq!(MIN.checked_next_multiple_of(-3), None);
-                assert_eq!(MIN.checked_next_multiple_of(-1), Some(MIN));
-            }
+            for n in ($T::MAX - 127)..=$T::MAX {
+                let isqrt: $T = n.isqrt();
 
-            #[test]
-            fn test_carrying_add() {
-                assert_eq!($T::MAX.carrying_add(1, false), ($T::MIN, true));
-                assert_eq!($T::MAX.carrying_add(0, true), ($T::MIN, true));
-                assert_eq!($T::MAX.carrying_add(1, true), ($T::MIN + 1, true));
-                assert_eq!($T::MAX.carrying_add(-1, false), ($T::MAX - 1, false));
-                assert_eq!($T::MAX.carrying_add(-1, true), ($T::MAX, false)); // no intermediate overflow
-                assert_eq!($T::MIN.carrying_add(-1, false), ($T::MAX, true));
-                assert_eq!($T::MIN.carrying_add(-1, true), ($T::MIN, false)); // no intermediate overflow
-                assert_eq!((0 as $T).carrying_add($T::MAX, true), ($T::MIN, true));
-                assert_eq!((0 as $T).carrying_add($T::MIN, true), ($T::MIN + 1, false));
+                assert!(isqrt.pow(2) <= n);
+                let (square, overflow) = (isqrt + 1).overflowing_pow(2);
+                assert!(overflow || square > n);
             }
+        }
 
-            #[test]
-            fn test_borrowing_sub() {
-                assert_eq!($T::MIN.borrowing_sub(1, false), ($T::MAX, true));
-                assert_eq!($T::MIN.borrowing_sub(0, true), ($T::MAX, true));
-                assert_eq!($T::MIN.borrowing_sub(1, true), ($T::MAX - 1, true));
-                assert_eq!($T::MIN.borrowing_sub(-1, false), ($T::MIN + 1, false));
-                assert_eq!($T::MIN.borrowing_sub(-1, true), ($T::MIN, false)); // no intermediate overflow
-                assert_eq!($T::MAX.borrowing_sub(-1, false), ($T::MIN, true));
-                assert_eq!($T::MAX.borrowing_sub(-1, true), ($T::MAX, false)); // no intermediate overflow
-                assert_eq!((0 as $T).borrowing_sub($T::MIN, false), ($T::MIN, true));
-                assert_eq!((0 as $T).borrowing_sub($T::MIN, true), ($T::MAX, false));
-            }
+        #[test]
+        fn test_div_floor() {
+            let a: $T = 8;
+            let b = 3;
+            assert_eq!(a.div_floor(b), 2);
+            assert_eq!(a.div_floor(-b), -3);
+            assert_eq!((-a).div_floor(b), -3);
+            assert_eq!((-a).div_floor(-b), 2);
+        }
 
-            #[test]
-            fn test_midpoint() {
-                assert_eq!(<$T>::midpoint(1, 3), 2);
-                assert_eq!(<$T>::midpoint(3, 1), 2);
-
-                assert_eq!(<$T>::midpoint(0, 0), 0);
-                assert_eq!(<$T>::midpoint(0, 2), 1);
-                assert_eq!(<$T>::midpoint(2, 0), 1);
-                assert_eq!(<$T>::midpoint(2, 2), 2);
-
-                assert_eq!(<$T>::midpoint(1, 4), 2);
-                assert_eq!(<$T>::midpoint(4, 1), 2);
-                assert_eq!(<$T>::midpoint(3, 4), 3);
-                assert_eq!(<$T>::midpoint(4, 3), 3);
-
-                assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MAX), -1);
-                assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MIN), -1);
-                assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MIN), <$T>::MIN);
-                assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MAX), <$T>::MAX);
-
-                assert_eq!(<$T>::midpoint(<$T>::MIN, 6), <$T>::MIN / 2 + 3);
-                assert_eq!(<$T>::midpoint(6, <$T>::MIN), <$T>::MIN / 2 + 3);
-                assert_eq!(<$T>::midpoint(<$T>::MAX, 6), <$T>::MAX / 2 + 3);
-                assert_eq!(<$T>::midpoint(6, <$T>::MAX), <$T>::MAX / 2 + 3);
-            }
+        #[test]
+        fn test_div_ceil() {
+            let a: $T = 8;
+            let b = 3;
+            assert_eq!(a.div_ceil(b), 3);
+            assert_eq!(a.div_ceil(-b), -2);
+            assert_eq!((-a).div_ceil(b), -2);
+            assert_eq!((-a).div_ceil(-b), 3);
+        }
+
+        #[test]
+        fn test_next_multiple_of() {
+            assert_eq!((16 as $T).next_multiple_of(8), 16);
+            assert_eq!((23 as $T).next_multiple_of(8), 24);
+            assert_eq!((16 as $T).next_multiple_of(-8), 16);
+            assert_eq!((23 as $T).next_multiple_of(-8), 16);
+            assert_eq!((-16 as $T).next_multiple_of(8), -16);
+            assert_eq!((-23 as $T).next_multiple_of(8), -16);
+            assert_eq!((-16 as $T).next_multiple_of(-8), -16);
+            assert_eq!((-23 as $T).next_multiple_of(-8), -24);
+            assert_eq!(MIN.next_multiple_of(-1), MIN);
+        }
+
+        #[test]
+        fn test_checked_next_multiple_of() {
+            assert_eq!((16 as $T).checked_next_multiple_of(8), Some(16));
+            assert_eq!((23 as $T).checked_next_multiple_of(8), Some(24));
+            assert_eq!((16 as $T).checked_next_multiple_of(-8), Some(16));
+            assert_eq!((23 as $T).checked_next_multiple_of(-8), Some(16));
+            assert_eq!((-16 as $T).checked_next_multiple_of(8), Some(-16));
+            assert_eq!((-23 as $T).checked_next_multiple_of(8), Some(-16));
+            assert_eq!((-16 as $T).checked_next_multiple_of(-8), Some(-16));
+            assert_eq!((-23 as $T).checked_next_multiple_of(-8), Some(-24));
+            assert_eq!((1 as $T).checked_next_multiple_of(0), None);
+            assert_eq!(MAX.checked_next_multiple_of(2), None);
+            assert_eq!(MIN.checked_next_multiple_of(-3), None);
+            assert_eq!(MIN.checked_next_multiple_of(-1), Some(MIN));
+        }
+
+        #[test]
+        fn test_carrying_add() {
+            assert_eq!($T::MAX.carrying_add(1, false), ($T::MIN, true));
+            assert_eq!($T::MAX.carrying_add(0, true), ($T::MIN, true));
+            assert_eq!($T::MAX.carrying_add(1, true), ($T::MIN + 1, true));
+            assert_eq!($T::MAX.carrying_add(-1, false), ($T::MAX - 1, false));
+            assert_eq!($T::MAX.carrying_add(-1, true), ($T::MAX, false)); // no intermediate overflow
+            assert_eq!($T::MIN.carrying_add(-1, false), ($T::MAX, true));
+            assert_eq!($T::MIN.carrying_add(-1, true), ($T::MIN, false)); // no intermediate overflow
+            assert_eq!((0 as $T).carrying_add($T::MAX, true), ($T::MIN, true));
+            assert_eq!((0 as $T).carrying_add($T::MIN, true), ($T::MIN + 1, false));
+        }
+
+        #[test]
+        fn test_borrowing_sub() {
+            assert_eq!($T::MIN.borrowing_sub(1, false), ($T::MAX, true));
+            assert_eq!($T::MIN.borrowing_sub(0, true), ($T::MAX, true));
+            assert_eq!($T::MIN.borrowing_sub(1, true), ($T::MAX - 1, true));
+            assert_eq!($T::MIN.borrowing_sub(-1, false), ($T::MIN + 1, false));
+            assert_eq!($T::MIN.borrowing_sub(-1, true), ($T::MIN, false)); // no intermediate overflow
+            assert_eq!($T::MAX.borrowing_sub(-1, false), ($T::MIN, true));
+            assert_eq!($T::MAX.borrowing_sub(-1, true), ($T::MAX, false)); // no intermediate overflow
+            assert_eq!((0 as $T).borrowing_sub($T::MIN, false), ($T::MIN, true));
+            assert_eq!((0 as $T).borrowing_sub($T::MIN, true), ($T::MAX, false));
+        }
+
+        #[test]
+        fn test_midpoint() {
+            assert_eq!(<$T>::midpoint(1, 3), 2);
+            assert_eq!(<$T>::midpoint(3, 1), 2);
+
+            assert_eq!(<$T>::midpoint(0, 0), 0);
+            assert_eq!(<$T>::midpoint(0, 2), 1);
+            assert_eq!(<$T>::midpoint(2, 0), 1);
+            assert_eq!(<$T>::midpoint(2, 2), 2);
+
+            assert_eq!(<$T>::midpoint(1, 4), 2);
+            assert_eq!(<$T>::midpoint(4, 1), 2);
+            assert_eq!(<$T>::midpoint(3, 4), 3);
+            assert_eq!(<$T>::midpoint(4, 3), 3);
+
+            assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MAX), -1);
+            assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MIN), -1);
+            assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MIN), <$T>::MIN);
+            assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MAX), <$T>::MAX);
+
+            assert_eq!(<$T>::midpoint(<$T>::MIN, 6), <$T>::MIN / 2 + 3);
+            assert_eq!(<$T>::midpoint(6, <$T>::MIN), <$T>::MIN / 2 + 3);
+            assert_eq!(<$T>::midpoint(<$T>::MAX, 6), <$T>::MAX / 2 + 3);
+            assert_eq!(<$T>::midpoint(6, <$T>::MAX), <$T>::MAX / 2 + 3);
         }
     };
 }
diff --git a/library/core/tests/num/mod.rs b/library/core/tests/num/mod.rs
index 53ff5ab1ced..dad46ad88fe 100644
--- a/library/core/tests/num/mod.rs
+++ b/library/core/tests/num/mod.rs
@@ -178,7 +178,7 @@ fn test_can_not_overflow() {
 
     // Check u128 separately:
     for base in 2..=36 {
-        let num = u128::MAX as u128;
+        let num = <u128>::MAX;
         let max_len_string = format_radix(num, base as u128);
         // base 16 fits perfectly for u128 and won't overflow:
         assert_eq!(can_overflow::<u128>(base, &max_len_string), base != 16);
diff --git a/library/core/tests/num/uint_macros.rs b/library/core/tests/num/uint_macros.rs
index d009ad89d5c..f4fa789461e 100644
--- a/library/core/tests/num/uint_macros.rs
+++ b/library/core/tests/num/uint_macros.rs
@@ -1,320 +1,317 @@
 macro_rules! uint_module {
     ($T:ident) => {
-        #[cfg(test)]
-        mod tests {
-            use core::ops::{BitAnd, BitOr, BitXor, Not, Shl, Shr};
-            use core::$T::*;
-            use std::str::FromStr;
-
-            use crate::num;
-
-            #[test]
-            fn test_overflows() {
-                assert!(MAX > 0);
-                assert!(MIN <= 0);
-                assert!((MIN + MAX).wrapping_add(1) == 0);
-            }
+        use core::ops::{BitAnd, BitOr, BitXor, Not, Shl, Shr};
+        use core::$T::*;
+        use std::str::FromStr;
 
-            #[test]
-            fn test_num() {
-                num::test_num(10 as $T, 2 as $T);
-            }
+        use crate::num;
 
-            #[test]
-            fn test_bitwise_operators() {
-                assert!(0b1110 as $T == (0b1100 as $T).bitor(0b1010 as $T));
-                assert!(0b1000 as $T == (0b1100 as $T).bitand(0b1010 as $T));
-                assert!(0b0110 as $T == (0b1100 as $T).bitxor(0b1010 as $T));
-                assert!(0b1110 as $T == (0b0111 as $T).shl(1));
-                assert!(0b0111 as $T == (0b1110 as $T).shr(1));
-                assert!(MAX - (0b1011 as $T) == (0b1011 as $T).not());
-            }
+        #[test]
+        fn test_overflows() {
+            assert!(MAX > 0);
+            assert!(MIN <= 0);
+            assert!((MIN + MAX).wrapping_add(1) == 0);
+        }
 
-            const A: $T = 0b0101100;
-            const B: $T = 0b0100001;
-            const C: $T = 0b1111001;
+        #[test]
+        fn test_num() {
+            num::test_num(10 as $T, 2 as $T);
+        }
 
-            const _0: $T = 0;
-            const _1: $T = !0;
+        #[test]
+        fn test_bitwise_operators() {
+            assert!(0b1110 as $T == (0b1100 as $T).bitor(0b1010 as $T));
+            assert!(0b1000 as $T == (0b1100 as $T).bitand(0b1010 as $T));
+            assert!(0b0110 as $T == (0b1100 as $T).bitxor(0b1010 as $T));
+            assert!(0b1110 as $T == (0b0111 as $T).shl(1));
+            assert!(0b0111 as $T == (0b1110 as $T).shr(1));
+            assert!(MAX - (0b1011 as $T) == (0b1011 as $T).not());
+        }
 
-            #[test]
-            fn test_count_ones() {
-                assert!(A.count_ones() == 3);
-                assert!(B.count_ones() == 2);
-                assert!(C.count_ones() == 5);
-            }
+        const A: $T = 0b0101100;
+        const B: $T = 0b0100001;
+        const C: $T = 0b1111001;
 
-            #[test]
-            fn test_count_zeros() {
-                assert!(A.count_zeros() == $T::BITS - 3);
-                assert!(B.count_zeros() == $T::BITS - 2);
-                assert!(C.count_zeros() == $T::BITS - 5);
-            }
+        const _0: $T = 0;
+        const _1: $T = !0;
 
-            #[test]
-            fn test_leading_trailing_ones() {
-                let a: $T = 0b0101_1111;
-                assert_eq!(a.trailing_ones(), 5);
-                assert_eq!((!a).leading_ones(), $T::BITS - 7);
+        #[test]
+        fn test_count_ones() {
+            assert!(A.count_ones() == 3);
+            assert!(B.count_ones() == 2);
+            assert!(C.count_ones() == 5);
+        }
 
-                assert_eq!(a.reverse_bits().leading_ones(), 5);
+        #[test]
+        fn test_count_zeros() {
+            assert!(A.count_zeros() == $T::BITS - 3);
+            assert!(B.count_zeros() == $T::BITS - 2);
+            assert!(C.count_zeros() == $T::BITS - 5);
+        }
 
-                assert_eq!(_1.leading_ones(), $T::BITS);
-                assert_eq!(_1.trailing_ones(), $T::BITS);
+        #[test]
+        fn test_leading_trailing_ones() {
+            let a: $T = 0b0101_1111;
+            assert_eq!(a.trailing_ones(), 5);
+            assert_eq!((!a).leading_ones(), $T::BITS - 7);
 
-                assert_eq!((_1 << 1).trailing_ones(), 0);
-                assert_eq!((_1 >> 1).leading_ones(), 0);
+            assert_eq!(a.reverse_bits().leading_ones(), 5);
 
-                assert_eq!((_1 << 1).leading_ones(), $T::BITS - 1);
-                assert_eq!((_1 >> 1).trailing_ones(), $T::BITS - 1);
+            assert_eq!(_1.leading_ones(), $T::BITS);
+            assert_eq!(_1.trailing_ones(), $T::BITS);
 
-                assert_eq!(_0.leading_ones(), 0);
-                assert_eq!(_0.trailing_ones(), 0);
+            assert_eq!((_1 << 1).trailing_ones(), 0);
+            assert_eq!((_1 >> 1).leading_ones(), 0);
 
-                let x: $T = 0b0010_1100;
-                assert_eq!(x.leading_ones(), 0);
-                assert_eq!(x.trailing_ones(), 0);
-            }
+            assert_eq!((_1 << 1).leading_ones(), $T::BITS - 1);
+            assert_eq!((_1 >> 1).trailing_ones(), $T::BITS - 1);
 
-            #[test]
-            fn test_rotate() {
-                assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
-                assert_eq!(B.rotate_left(3).rotate_left(2).rotate_right(5), B);
-                assert_eq!(C.rotate_left(6).rotate_right(2).rotate_right(4), C);
-
-                // Rotating these should make no difference
-                //
-                // We test using 124 bits because to ensure that overlong bit shifts do
-                // not cause undefined behaviour. See #10183.
-                assert_eq!(_0.rotate_left(124), _0);
-                assert_eq!(_1.rotate_left(124), _1);
-                assert_eq!(_0.rotate_right(124), _0);
-                assert_eq!(_1.rotate_right(124), _1);
-
-                // Rotating by 0 should have no effect
-                assert_eq!(A.rotate_left(0), A);
-                assert_eq!(B.rotate_left(0), B);
-                assert_eq!(C.rotate_left(0), C);
-                // Rotating by a multiple of word size should also have no effect
-                assert_eq!(A.rotate_left(128), A);
-                assert_eq!(B.rotate_left(128), B);
-                assert_eq!(C.rotate_left(128), C);
-            }
+            assert_eq!(_0.leading_ones(), 0);
+            assert_eq!(_0.trailing_ones(), 0);
 
-            #[test]
-            fn test_swap_bytes() {
-                assert_eq!(A.swap_bytes().swap_bytes(), A);
-                assert_eq!(B.swap_bytes().swap_bytes(), B);
-                assert_eq!(C.swap_bytes().swap_bytes(), C);
+            let x: $T = 0b0010_1100;
+            assert_eq!(x.leading_ones(), 0);
+            assert_eq!(x.trailing_ones(), 0);
+        }
 
-                // Swapping these should make no difference
-                assert_eq!(_0.swap_bytes(), _0);
-                assert_eq!(_1.swap_bytes(), _1);
-            }
+        #[test]
+        fn test_rotate() {
+            assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
+            assert_eq!(B.rotate_left(3).rotate_left(2).rotate_right(5), B);
+            assert_eq!(C.rotate_left(6).rotate_right(2).rotate_right(4), C);
+
+            // Rotating these should make no difference
+            //
+            // We test using 124 bits because to ensure that overlong bit shifts do
+            // not cause undefined behaviour. See #10183.
+            assert_eq!(_0.rotate_left(124), _0);
+            assert_eq!(_1.rotate_left(124), _1);
+            assert_eq!(_0.rotate_right(124), _0);
+            assert_eq!(_1.rotate_right(124), _1);
+
+            // Rotating by 0 should have no effect
+            assert_eq!(A.rotate_left(0), A);
+            assert_eq!(B.rotate_left(0), B);
+            assert_eq!(C.rotate_left(0), C);
+            // Rotating by a multiple of word size should also have no effect
+            assert_eq!(A.rotate_left(128), A);
+            assert_eq!(B.rotate_left(128), B);
+            assert_eq!(C.rotate_left(128), C);
+        }
 
-            #[test]
-            fn test_reverse_bits() {
-                assert_eq!(A.reverse_bits().reverse_bits(), A);
-                assert_eq!(B.reverse_bits().reverse_bits(), B);
-                assert_eq!(C.reverse_bits().reverse_bits(), C);
+        #[test]
+        fn test_swap_bytes() {
+            assert_eq!(A.swap_bytes().swap_bytes(), A);
+            assert_eq!(B.swap_bytes().swap_bytes(), B);
+            assert_eq!(C.swap_bytes().swap_bytes(), C);
 
-                // Swapping these should make no difference
-                assert_eq!(_0.reverse_bits(), _0);
-                assert_eq!(_1.reverse_bits(), _1);
-            }
+            // Swapping these should make no difference
+            assert_eq!(_0.swap_bytes(), _0);
+            assert_eq!(_1.swap_bytes(), _1);
+        }
 
-            #[test]
-            fn test_le() {
-                assert_eq!($T::from_le(A.to_le()), A);
-                assert_eq!($T::from_le(B.to_le()), B);
-                assert_eq!($T::from_le(C.to_le()), C);
-                assert_eq!($T::from_le(_0), _0);
-                assert_eq!($T::from_le(_1), _1);
-                assert_eq!(_0.to_le(), _0);
-                assert_eq!(_1.to_le(), _1);
-            }
+        #[test]
+        fn test_reverse_bits() {
+            assert_eq!(A.reverse_bits().reverse_bits(), A);
+            assert_eq!(B.reverse_bits().reverse_bits(), B);
+            assert_eq!(C.reverse_bits().reverse_bits(), C);
 
-            #[test]
-            fn test_be() {
-                assert_eq!($T::from_be(A.to_be()), A);
-                assert_eq!($T::from_be(B.to_be()), B);
-                assert_eq!($T::from_be(C.to_be()), C);
-                assert_eq!($T::from_be(_0), _0);
-                assert_eq!($T::from_be(_1), _1);
-                assert_eq!(_0.to_be(), _0);
-                assert_eq!(_1.to_be(), _1);
-            }
+            // Swapping these should make no difference
+            assert_eq!(_0.reverse_bits(), _0);
+            assert_eq!(_1.reverse_bits(), _1);
+        }
 
-            #[test]
-            fn test_unsigned_checked_div() {
-                assert!((10 as $T).checked_div(2) == Some(5));
-                assert!((5 as $T).checked_div(0) == None);
-            }
+        #[test]
+        fn test_le() {
+            assert_eq!($T::from_le(A.to_le()), A);
+            assert_eq!($T::from_le(B.to_le()), B);
+            assert_eq!($T::from_le(C.to_le()), C);
+            assert_eq!($T::from_le(_0), _0);
+            assert_eq!($T::from_le(_1), _1);
+            assert_eq!(_0.to_le(), _0);
+            assert_eq!(_1.to_le(), _1);
+        }
 
-            fn from_str<T: FromStr>(t: &str) -> Option<T> {
-                FromStr::from_str(t).ok()
-            }
+        #[test]
+        fn test_be() {
+            assert_eq!($T::from_be(A.to_be()), A);
+            assert_eq!($T::from_be(B.to_be()), B);
+            assert_eq!($T::from_be(C.to_be()), C);
+            assert_eq!($T::from_be(_0), _0);
+            assert_eq!($T::from_be(_1), _1);
+            assert_eq!(_0.to_be(), _0);
+            assert_eq!(_1.to_be(), _1);
+        }
 
-            #[test]
-            pub fn test_from_str() {
-                assert_eq!(from_str::<$T>("0"), Some(0 as $T));
-                assert_eq!(from_str::<$T>("3"), Some(3 as $T));
-                assert_eq!(from_str::<$T>("10"), Some(10 as $T));
-                assert_eq!(from_str::<u32>("123456789"), Some(123456789 as u32));
-                assert_eq!(from_str::<$T>("00100"), Some(100 as $T));
-
-                assert_eq!(from_str::<$T>(""), None);
-                assert_eq!(from_str::<$T>(" "), None);
-                assert_eq!(from_str::<$T>("x"), None);
-            }
+        #[test]
+        fn test_unsigned_checked_div() {
+            assert!((10 as $T).checked_div(2) == Some(5));
+            assert!((5 as $T).checked_div(0) == None);
+        }
 
-            #[test]
-            pub fn test_parse_bytes() {
-                assert_eq!($T::from_str_radix("123", 10), Ok(123 as $T));
-                assert_eq!($T::from_str_radix("1001", 2), Ok(9 as $T));
-                assert_eq!($T::from_str_radix("123", 8), Ok(83 as $T));
-                assert_eq!(u16::from_str_radix("123", 16), Ok(291 as u16));
-                assert_eq!(u16::from_str_radix("ffff", 16), Ok(65535 as u16));
-                assert_eq!($T::from_str_radix("z", 36), Ok(35 as $T));
-
-                assert_eq!($T::from_str_radix("Z", 10).ok(), None::<$T>);
-                assert_eq!($T::from_str_radix("_", 2).ok(), None::<$T>);
-            }
+        fn from_str<T: FromStr>(t: &str) -> Option<T> {
+            FromStr::from_str(t).ok()
+        }
 
-            #[test]
-            fn test_pow() {
-                let mut r = 2 as $T;
-                assert_eq!(r.pow(2), 4 as $T);
-                assert_eq!(r.pow(0), 1 as $T);
-                assert_eq!(r.wrapping_pow(2), 4 as $T);
-                assert_eq!(r.wrapping_pow(0), 1 as $T);
-                assert_eq!(r.checked_pow(2), Some(4 as $T));
-                assert_eq!(r.checked_pow(0), Some(1 as $T));
-                assert_eq!(r.overflowing_pow(2), (4 as $T, false));
-                assert_eq!(r.overflowing_pow(0), (1 as $T, false));
-                assert_eq!(r.saturating_pow(2), 4 as $T);
-                assert_eq!(r.saturating_pow(0), 1 as $T);
-
-                r = MAX;
-                // use `^` to represent .pow() with no overflow.
-                // if itest::MAX == 2^j-1, then itest is a `j` bit int,
-                // so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
-                // thussaturating_pow the overflowing result is exactly 1.
-                assert_eq!(r.wrapping_pow(2), 1 as $T);
-                assert_eq!(r.checked_pow(2), None);
-                assert_eq!(r.overflowing_pow(2), (1 as $T, true));
-                assert_eq!(r.saturating_pow(2), MAX);
-            }
+        #[test]
+        pub fn test_from_str() {
+            assert_eq!(from_str::<$T>("0"), Some(0 as $T));
+            assert_eq!(from_str::<$T>("3"), Some(3 as $T));
+            assert_eq!(from_str::<$T>("10"), Some(10 as $T));
+            assert_eq!(from_str::<u32>("123456789"), Some(123456789 as u32));
+            assert_eq!(from_str::<$T>("00100"), Some(100 as $T));
+
+            assert_eq!(from_str::<$T>(""), None);
+            assert_eq!(from_str::<$T>(" "), None);
+            assert_eq!(from_str::<$T>("x"), None);
+        }
 
-            #[test]
-            fn test_isqrt() {
-                assert_eq!((0 as $T).isqrt(), 0 as $T);
-                assert_eq!((1 as $T).isqrt(), 1 as $T);
-                assert_eq!((2 as $T).isqrt(), 1 as $T);
-                assert_eq!((99 as $T).isqrt(), 9 as $T);
-                assert_eq!((100 as $T).isqrt(), 10 as $T);
-                assert_eq!($T::MAX.isqrt(), (1 << ($T::BITS / 2)) - 1);
-            }
+        #[test]
+        pub fn test_parse_bytes() {
+            assert_eq!($T::from_str_radix("123", 10), Ok(123 as $T));
+            assert_eq!($T::from_str_radix("1001", 2), Ok(9 as $T));
+            assert_eq!($T::from_str_radix("123", 8), Ok(83 as $T));
+            assert_eq!(u16::from_str_radix("123", 16), Ok(291 as u16));
+            assert_eq!(u16::from_str_radix("ffff", 16), Ok(65535 as u16));
+            assert_eq!($T::from_str_radix("z", 36), Ok(35 as $T));
+
+            assert_eq!($T::from_str_radix("Z", 10).ok(), None::<$T>);
+            assert_eq!($T::from_str_radix("_", 2).ok(), None::<$T>);
+        }
 
-            #[cfg(not(miri))] // Miri is too slow
-            #[test]
-            fn test_lots_of_isqrt() {
-                let n_max: $T = (1024 * 1024).min($T::MAX as u128) as $T;
-                for n in 0..=n_max {
-                    let isqrt: $T = n.isqrt();
+        #[test]
+        fn test_pow() {
+            let mut r = 2 as $T;
+            assert_eq!(r.pow(2), 4 as $T);
+            assert_eq!(r.pow(0), 1 as $T);
+            assert_eq!(r.wrapping_pow(2), 4 as $T);
+            assert_eq!(r.wrapping_pow(0), 1 as $T);
+            assert_eq!(r.checked_pow(2), Some(4 as $T));
+            assert_eq!(r.checked_pow(0), Some(1 as $T));
+            assert_eq!(r.overflowing_pow(2), (4 as $T, false));
+            assert_eq!(r.overflowing_pow(0), (1 as $T, false));
+            assert_eq!(r.saturating_pow(2), 4 as $T);
+            assert_eq!(r.saturating_pow(0), 1 as $T);
+
+            r = MAX;
+            // use `^` to represent .pow() with no overflow.
+            // if itest::MAX == 2^j-1, then itest is a `j` bit int,
+            // so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
+            // thussaturating_pow the overflowing result is exactly 1.
+            assert_eq!(r.wrapping_pow(2), 1 as $T);
+            assert_eq!(r.checked_pow(2), None);
+            assert_eq!(r.overflowing_pow(2), (1 as $T, true));
+            assert_eq!(r.saturating_pow(2), MAX);
+        }
 
-                    assert!(isqrt.pow(2) <= n);
-                    assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
-                }
+        #[test]
+        fn test_isqrt() {
+            assert_eq!((0 as $T).isqrt(), 0 as $T);
+            assert_eq!((1 as $T).isqrt(), 1 as $T);
+            assert_eq!((2 as $T).isqrt(), 1 as $T);
+            assert_eq!((99 as $T).isqrt(), 9 as $T);
+            assert_eq!((100 as $T).isqrt(), 10 as $T);
+            assert_eq!($T::MAX.isqrt(), (1 << ($T::BITS / 2)) - 1);
+        }
 
-                for n in ($T::MAX - 255)..=$T::MAX {
-                    let isqrt: $T = n.isqrt();
+        #[cfg(not(miri))] // Miri is too slow
+        #[test]
+        fn test_lots_of_isqrt() {
+            let n_max: $T = (1024 * 1024).min($T::MAX as u128) as $T;
+            for n in 0..=n_max {
+                let isqrt: $T = n.isqrt();
 
-                    assert!(isqrt.pow(2) <= n);
-                    assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
-                }
+                assert!(isqrt.pow(2) <= n);
+                assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
             }
 
-            #[test]
-            fn test_div_floor() {
-                assert_eq!((8 as $T).div_floor(3), 2);
-            }
+            for n in ($T::MAX - 255)..=$T::MAX {
+                let isqrt: $T = n.isqrt();
 
-            #[test]
-            fn test_div_ceil() {
-                assert_eq!((8 as $T).div_ceil(3), 3);
+                assert!(isqrt.pow(2) <= n);
+                assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
             }
+        }
 
-            #[test]
-            fn test_next_multiple_of() {
-                assert_eq!((16 as $T).next_multiple_of(8), 16);
-                assert_eq!((23 as $T).next_multiple_of(8), 24);
-                assert_eq!(MAX.next_multiple_of(1), MAX);
-            }
+        #[test]
+        fn test_div_floor() {
+            assert_eq!((8 as $T).div_floor(3), 2);
+        }
 
-            #[test]
-            fn test_checked_next_multiple_of() {
-                assert_eq!((16 as $T).checked_next_multiple_of(8), Some(16));
-                assert_eq!((23 as $T).checked_next_multiple_of(8), Some(24));
-                assert_eq!((1 as $T).checked_next_multiple_of(0), None);
-                assert_eq!(MAX.checked_next_multiple_of(2), None);
-            }
+        #[test]
+        fn test_div_ceil() {
+            assert_eq!((8 as $T).div_ceil(3), 3);
+        }
 
-            #[test]
-            fn test_is_next_multiple_of() {
-                assert!((12 as $T).is_multiple_of(4));
-                assert!(!(12 as $T).is_multiple_of(5));
-                assert!((0 as $T).is_multiple_of(0));
-                assert!(!(12 as $T).is_multiple_of(0));
-            }
+        #[test]
+        fn test_next_multiple_of() {
+            assert_eq!((16 as $T).next_multiple_of(8), 16);
+            assert_eq!((23 as $T).next_multiple_of(8), 24);
+            assert_eq!(MAX.next_multiple_of(1), MAX);
+        }
 
-            #[test]
-            fn test_carrying_add() {
-                assert_eq!($T::MAX.carrying_add(1, false), (0, true));
-                assert_eq!($T::MAX.carrying_add(0, true), (0, true));
-                assert_eq!($T::MAX.carrying_add(1, true), (1, true));
+        #[test]
+        fn test_checked_next_multiple_of() {
+            assert_eq!((16 as $T).checked_next_multiple_of(8), Some(16));
+            assert_eq!((23 as $T).checked_next_multiple_of(8), Some(24));
+            assert_eq!((1 as $T).checked_next_multiple_of(0), None);
+            assert_eq!(MAX.checked_next_multiple_of(2), None);
+        }
 
-                assert_eq!($T::MIN.carrying_add($T::MAX, false), ($T::MAX, false));
-                assert_eq!($T::MIN.carrying_add(0, true), (1, false));
-                assert_eq!($T::MIN.carrying_add($T::MAX, true), (0, true));
-            }
+        #[test]
+        fn test_is_next_multiple_of() {
+            assert!((12 as $T).is_multiple_of(4));
+            assert!(!(12 as $T).is_multiple_of(5));
+            assert!((0 as $T).is_multiple_of(0));
+            assert!(!(12 as $T).is_multiple_of(0));
+        }
 
-            #[test]
-            fn test_borrowing_sub() {
-                assert_eq!($T::MIN.borrowing_sub(1, false), ($T::MAX, true));
-                assert_eq!($T::MIN.borrowing_sub(0, true), ($T::MAX, true));
-                assert_eq!($T::MIN.borrowing_sub(1, true), ($T::MAX - 1, true));
+        #[test]
+        fn test_carrying_add() {
+            assert_eq!($T::MAX.carrying_add(1, false), (0, true));
+            assert_eq!($T::MAX.carrying_add(0, true), (0, true));
+            assert_eq!($T::MAX.carrying_add(1, true), (1, true));
 
-                assert_eq!($T::MAX.borrowing_sub($T::MAX, false), (0, false));
-                assert_eq!($T::MAX.borrowing_sub(0, true), ($T::MAX - 1, false));
-                assert_eq!($T::MAX.borrowing_sub($T::MAX, true), ($T::MAX, true));
-            }
+            assert_eq!($T::MIN.carrying_add($T::MAX, false), ($T::MAX, false));
+            assert_eq!($T::MIN.carrying_add(0, true), (1, false));
+            assert_eq!($T::MIN.carrying_add($T::MAX, true), (0, true));
+        }
 
-            #[test]
-            fn test_midpoint() {
-                assert_eq!(<$T>::midpoint(1, 3), 2);
-                assert_eq!(<$T>::midpoint(3, 1), 2);
-
-                assert_eq!(<$T>::midpoint(0, 0), 0);
-                assert_eq!(<$T>::midpoint(0, 2), 1);
-                assert_eq!(<$T>::midpoint(2, 0), 1);
-                assert_eq!(<$T>::midpoint(2, 2), 2);
-
-                assert_eq!(<$T>::midpoint(1, 4), 2);
-                assert_eq!(<$T>::midpoint(4, 1), 2);
-                assert_eq!(<$T>::midpoint(3, 4), 3);
-                assert_eq!(<$T>::midpoint(4, 3), 3);
-
-                assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MAX), (<$T>::MAX - <$T>::MIN) / 2);
-                assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MIN), (<$T>::MAX - <$T>::MIN) / 2);
-                assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MIN), <$T>::MIN);
-                assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MAX), <$T>::MAX);
-
-                assert_eq!(<$T>::midpoint(<$T>::MIN, 6), <$T>::MIN / 2 + 3);
-                assert_eq!(<$T>::midpoint(6, <$T>::MIN), <$T>::MIN / 2 + 3);
-                assert_eq!(<$T>::midpoint(<$T>::MAX, 6), (<$T>::MAX - <$T>::MIN) / 2 + 3);
-                assert_eq!(<$T>::midpoint(6, <$T>::MAX), (<$T>::MAX - <$T>::MIN) / 2 + 3);
-            }
+        #[test]
+        fn test_borrowing_sub() {
+            assert_eq!($T::MIN.borrowing_sub(1, false), ($T::MAX, true));
+            assert_eq!($T::MIN.borrowing_sub(0, true), ($T::MAX, true));
+            assert_eq!($T::MIN.borrowing_sub(1, true), ($T::MAX - 1, true));
+
+            assert_eq!($T::MAX.borrowing_sub($T::MAX, false), (0, false));
+            assert_eq!($T::MAX.borrowing_sub(0, true), ($T::MAX - 1, false));
+            assert_eq!($T::MAX.borrowing_sub($T::MAX, true), ($T::MAX, true));
+        }
+
+        #[test]
+        fn test_midpoint() {
+            assert_eq!(<$T>::midpoint(1, 3), 2);
+            assert_eq!(<$T>::midpoint(3, 1), 2);
+
+            assert_eq!(<$T>::midpoint(0, 0), 0);
+            assert_eq!(<$T>::midpoint(0, 2), 1);
+            assert_eq!(<$T>::midpoint(2, 0), 1);
+            assert_eq!(<$T>::midpoint(2, 2), 2);
+
+            assert_eq!(<$T>::midpoint(1, 4), 2);
+            assert_eq!(<$T>::midpoint(4, 1), 2);
+            assert_eq!(<$T>::midpoint(3, 4), 3);
+            assert_eq!(<$T>::midpoint(4, 3), 3);
+
+            assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MAX), (<$T>::MAX - <$T>::MIN) / 2);
+            assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MIN), (<$T>::MAX - <$T>::MIN) / 2);
+            assert_eq!(<$T>::midpoint(<$T>::MIN, <$T>::MIN), <$T>::MIN);
+            assert_eq!(<$T>::midpoint(<$T>::MAX, <$T>::MAX), <$T>::MAX);
+
+            assert_eq!(<$T>::midpoint(<$T>::MIN, 6), <$T>::MIN / 2 + 3);
+            assert_eq!(<$T>::midpoint(6, <$T>::MIN), <$T>::MIN / 2 + 3);
+            assert_eq!(<$T>::midpoint(<$T>::MAX, 6), (<$T>::MAX - <$T>::MIN) / 2 + 3);
+            assert_eq!(<$T>::midpoint(6, <$T>::MAX), (<$T>::MAX - <$T>::MIN) / 2 + 3);
         }
     };
 }