diff --git a/wp-includes/nav-menu.php b/wp-includes/nav-menu.php
index f130d2f3e1..b618f96e9b 100644
--- a/wp-includes/nav-menu.php
+++ b/wp-includes/nav-menu.php
@@ -92,6 +92,13 @@ function register_nav_menus( $locations = array() ) {
 
 	add_theme_support( 'menus' );
 
+	foreach ( $locations as $key => $value ) {
+		if ( is_int( $key ) ) {
+			_doing_it_wrong( __FUNCTION__, __( 'Nav menu locations must be strings.' ), '5.3' );
+			break;
+		}
+	}
+
 	$_wp_registered_nav_menus = array_merge( (array) $_wp_registered_nav_menus, $locations );
 }
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a9c177a11b..77e280aec6 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-46101';
+$wp_version = '5.3-alpha-46102';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.