Reverted in 3.1. We’re trying again in 3.2.

If you were using $wpdb->last_result, you will need to change it to $wpdb->get_results() without a $query argument, which does the same thing. Inside wpdb, we’re now passing resources around, so the last_result property (which was private and should not have been used) no longer exists.

On PHP5, we’re using a magic getter to return wpdb->get_results() for you, but it’ll throw a deprecated warning. On PHP4, your code will cease to work.

Further reading: #12257.