add pow(2) to negative exp

Author: Neutron3529

src/libcore/tests/num/int_macros.rs

@@ -278,14 +278,19 @@ macro_rules! int_module {
                 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(3), Some(-8) as $T);
-                assert_eq!(r.checked_pow(0), Some(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);
             }