diff --git a/src/wp-includes/class-wp.php b/src/wp-includes/class-wp.php
index 6eb6177c09..9765a01507 100644
--- a/src/wp-includes/class-wp.php
+++ b/src/wp-includes/class-wp.php
@@ -252,7 +252,7 @@ class WP {
 				}
 			}
 
-			if ( isset( $this->matched_rule ) ) {
+			if ( ! empty( $this->matched_rule ) ) {
 				// Trim the query of everything up to the '?'.
 				$query = preg_replace( '!^.+\?!', '', $query );