auto merge of #7163 : brson/rust/reinterpret-cast, r=thestinger

Author: bors

src/libstd/cast.rs

@@ -54,17 +54,14 @@ pub unsafe fn transmute_copy<T, U>(src: &T) -> U {
  *
  * The forget function will take ownership of the provided value but neglect
  * to run any required cleanup or memory-management operations on it. This
- * can be used for various acts of magick, particularly when using
- * reinterpret_cast on pointer types.
+ * can be used for various acts of magick.
  */
 #[inline(always)]
 pub unsafe fn forget<T>(thing: T) { intrinsics::forget(thing); }
 
 /**
  * Force-increment the reference count on a shared box. If used
- * carelessly, this can leak the box. Use this in conjunction with transmute
- * and/or reinterpret_cast when such calls would otherwise scramble a box's
- * reference count
+ * carelessly, this can leak the box.
  */
 #[inline(always)]
 pub unsafe fn bump_box_refcount<T>(t: @T) { forget(t); }