std: Clean up the swap function a little

Author: brson

src/libstd/util.rs

@@ -26,19 +26,16 @@ pub fn id<T>(x: T) -> T { x }
 pub fn swap<T>(x: &mut T, y: &mut T) {
     unsafe {
         // Give ourselves some scratch space to work with
-        let mut tmp: T = mem::uninit();
-        let t: *mut T = &mut tmp;
+        let mut t: T = mem::uninit();
 
         // Perform the swap, `&mut` pointers never alias
-        let x_raw: *mut T = x;
-        let y_raw: *mut T = y;
-        ptr::copy_nonoverlapping_memory(t, &*x_raw, 1);
-        ptr::copy_nonoverlapping_memory(x, &*y_raw, 1);
-        ptr::copy_nonoverlapping_memory(y, &*t, 1);
+        ptr::copy_nonoverlapping_memory(&mut t, &*x, 1);
+        ptr::copy_nonoverlapping_memory(x, &*y, 1);
+        ptr::copy_nonoverlapping_memory(y, &t, 1);
 
         // y and t now point to the same thing, but we need to completely forget `tmp`
         // because it's no longer relevant.
-        cast::forget(tmp);
+        cast::forget(t);
     }
 }