Index: wp-includes/class-wp-rewrite.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- wp-includes/class-wp-rewrite.php	(date 1522701591000)
+++ wp-includes/class-wp-rewrite.php	(date 1522703099000)
@@ -1484,10 +1484,6 @@
 	 * @return string
 	 */
 	public function mod_rewrite_rules() {
-		if ( ! $this->using_permalinks() ) {
-			return '';
-		}
-
 		$site_root = parse_url( site_url() );
 		if ( isset( $site_root['path'] ) ) {
 			$site_root = trailingslashit( $site_root['path'] );