fix tests

Author: ljedrz

src/libstd/path.rs

@@ -408,7 +408,7 @@ enum State {
 ///         assert_eq!(Prefix::Disk(b'C'), prefix_component.kind());
 ///         assert_eq!(OsStr::new("c:"), prefix_component.as_os_str());
 ///     }
-///     _ => unsafe { ::core::hint::unreachable_unchecked() },
+///     _ => unreachable!(),
 /// }
 /// # }
 /// ```

src/libstd/sync/rwlock.rs

@@ -224,7 +224,7 @@ impl<T: ?Sized> RwLock<T> {
     ///
     /// match lock.try_read() {
     ///     Ok(n) => assert_eq!(*n, 1),
-    ///     Err(_) => unsafe { ::core::hint::unreachable_unchecked() },
+    ///     Err(_) => unreachable!(),
     /// };
     /// ```
     #[inline]

src/libstd/sys_common/poison.rs

@@ -82,7 +82,7 @@ pub struct Guard {
 /// }).join();
 ///
 /// match mutex.lock() {
-///     Ok(_) => unsafe { ::core::hint::unreachable_unchecked() },
+///     Ok(_) => unreachable!(),
 ///     Err(p_err) => {
 ///         let data = p_err.get_ref();
 ///         println!("recovered: {}", data);