Allow none Sized types in assert_eq!

format_args! doesn't support none Sized types so we should just pass it the references to left_val and right_val.

This fixes `assert_eq!([1, 2, 3][..], vec![1, 2, 3][..])` for example.

src/libcore/macros.rs

@@ -89,7 +89,7 @@ macro_rules! assert_eq {
             (left_val, right_val) => {
                 if !(*left_val == *right_val) {
                     panic!("assertion failed: `(left == right)` \
-                           (left: `{:?}`, right: `{:?}`)", *left_val, *right_val)
+                           (left: `{:?}`, right: `{:?}`)", left_val, right_val)
                 }
             }
         }