Index: comment.php
===================================================================
--- comment.php	(revision 21501)
+++ comment.php	(working copy)
@@ -314,6 +314,9 @@
 			$where .= " AND comment_type = ''";
 		} elseif( 'pings' == $type ) {
 			$where .= ' AND comment_type IN ("pingback", "trackback")';
+		} elseif ( ! empty( $type ) && is_array( $type ) ) {
+			$type = array_map( 'sanitize_key', $type );
+			$where .= " AND comment_type IN ('" . join("', '", $type) . "')";
 		} elseif ( ! empty( $type ) ) {
 			$where .= $wpdb->prepare( ' AND comment_type = %s', $type );
 		}