diff --git a/wp-includes/class-wp-widget.php b/wp-includes/class-wp-widget.php
index fa206e7d35..e91f5cd9f9 100644
--- a/wp-includes/class-wp-widget.php
+++ b/wp-includes/class-wp-widget.php
@@ -365,7 +365,7 @@ class WP_Widget {
 		$this->_set( $widget_args['number'] );
 		$instances = $this->get_settings();
 
-		if ( array_key_exists( $this->number, $instances ) ) {
+		if ( isset( $instances[ $this->number ] ) ) {
 			$instance = $instances[ $this->number ];
 
 			/**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 497c1239f8..723ee2b3f3 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-52172';
+$wp_version = '5.9-alpha-52173';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.