diff --git a/src/wp-includes/class-wp-widget-factory.php b/src/wp-includes/class-wp-widget-factory.php
index 68f4623098..ec5a96d6a9 100644
--- a/src/wp-includes/class-wp-widget-factory.php
+++ b/src/wp-includes/class-wp-widget-factory.php
@@ -55,35 +55,6 @@ class WP_Widget_Factory {
 	 */
 	private $hashed_class_counts = array();
 
-	/**
-	 * Hashes an object, doing fallback of `spl_object_hash()` if not available.
-	 *
-	 * This can be eliminated in favor of straight spl_object_hash() when 5.3
-	 * is the minimum requirement for PHP.
-	 *
-	 * @since 4.6.0
-	 *
-	 * @param WP_Widget $widget Widget.
-	 * @return string Object hash.
-	 */
-	private function hash_object( $widget ) {
-		if ( function_exists( 'spl_object_hash' ) ) {
-			return spl_object_hash( $widget );
-		} else {
-			$class_name = get_class( $widget );
-			$hash       = $class_name;
-			if ( ! isset( $widget->_wp_widget_factory_hash_id ) ) {
-				if ( ! isset( $this->hashed_class_counts[ $class_name ] ) ) {
-					$this->hashed_class_counts[ $class_name ] = 0;
-				}
-				$this->hashed_class_counts[ $class_name ] += 1;
-				$widget->_wp_widget_factory_hash_id        = $this->hashed_class_counts[ $class_name ];
-			}
-			$hash .= ':' . $widget->_wp_widget_factory_hash_id;
-			return $hash;
-		}
-	}
-
 	/**
 	 * Registers a widget subclass.
 	 *
@@ -95,7 +66,7 @@ class WP_Widget_Factory {
 	 */
 	public function register( $widget ) {
 		if ( $widget instanceof WP_Widget ) {
-			$this->widgets[ $this->hash_object( $widget ) ] = $widget;
+			$this->widgets[ spl_object_hash( $widget ) ] = $widget;
 		} else {
 			$this->widgets[ $widget ] = new $widget();
 		}
@@ -112,7 +83,7 @@ class WP_Widget_Factory {
 	 */
 	public function unregister( $widget ) {
 		if ( $widget instanceof WP_Widget ) {
-			unset( $this->widgets[ $this->hash_object( $widget ) ] );
+			unset( $this->widgets[ spl_object_hash( $widget ) ] );
 		} else {
 			unset( $this->widgets[ $widget ] );
 		}
diff --git a/src/wp-includes/plugin.php b/src/wp-includes/plugin.php
index 1f6cacd5b4..c83ebdb81f 100644
--- a/src/wp-includes/plugin.php
+++ b/src/wp-includes/plugin.php
@@ -925,23 +925,7 @@ function _wp_filter_build_unique_id( $tag, $function, $priority ) {
 
 	if ( is_object( $function[0] ) ) {
 		// Object Class Calling
-		if ( function_exists( 'spl_object_hash' ) ) {
-			return spl_object_hash( $function[0] ) . $function[1];
-		} else {
-			$obj_idx = get_class( $function[0] ) . $function[1];
-			if ( ! isset( $function[0]->wp_filter_id ) ) {
-				if ( false === $priority ) {
-					return false;
-				}
-				$obj_idx                  .= isset( $wp_filter[ $tag ][ $priority ] ) ? count( (array) $wp_filter[ $tag ][ $priority ] ) : $filter_id_count;
-				$function[0]->wp_filter_id = $filter_id_count;
-				++$filter_id_count;
-			} else {
-				$obj_idx .= $function[0]->wp_filter_id;
-			}
-
-			return $obj_idx;
-		}
+		return spl_object_hash( $function[0] ) . $function[1];
 	} elseif ( is_string( $function[0] ) ) {
 		// Static Calling
 		return $function[0] . '::' . $function[1];