Source 
  File: wp-includes/functions.php 
 function _deprecated_constructor( $class, $version, $parent_class = '' ) {
	/**
	 * Fires when a deprecated constructor is called.
	 *
	 * @since 4.3.0
	 * @since 4.5.0 Added the `$parent_class` parameter.
	 *
	 * @param string $class        The class containing the deprecated constructor.
	 * @param string $version      The version of WordPress that deprecated the function.
	 * @param string $parent_class The parent class calling the deprecated constructor.
	 */
	do_action( 'deprecated_constructor_run', $class, $version, $parent_class );
	/**
	 * Filters whether to trigger an error for deprecated functions.
	 *
	 * `WP_DEBUG` must be true in addition to the filter evaluating to true.
	 *
	 * @since 4.3.0
	 *
	 * @param bool $trigger Whether to trigger the error for deprecated functions. Default true.
	 */
	if ( WP_DEBUG && apply_filters( 'deprecated_constructor_trigger_error', true ) ) {
		if ( function_exists( '__' ) ) {
			if ( $parent_class ) {
				trigger_error(
					sprintf(
						/* translators: 1: PHP class name, 2: PHP parent class name, 3: Version number, 4: __construct() method. */
						__( 'The called constructor method for %1$s in %2$s is <strong>deprecated</strong> since version %3$s! Use %4$s instead.' ),
						$class,
						$parent_class,
						$version,
						'<code>__construct()</code>'
					),
					E_USER_DEPRECATED
				);
			} else {
				trigger_error(
					sprintf(
						/* translators: 1: PHP class name, 2: Version number, 3: __construct() method. */
						__( 'The called constructor method for %1$s is <strong>deprecated</strong> since version %2$s! Use %3$s instead.' ),
						$class,
						$version,
						'<code>__construct()</code>'
					),
					E_USER_DEPRECATED
				);
			}
		} else {
			if ( $parent_class ) {
				trigger_error(
					sprintf(
						'The called constructor method for %1$s in %2$s is <strong>deprecated</strong> since version %3$s! Use %4$s instead.',
						$class,
						$parent_class,
						$version,
						'<code>__construct()</code>'
					),
					E_USER_DEPRECATED
				);
			} else {
				trigger_error(
					sprintf(
						'The called constructor method for %1$s is <strong>deprecated</strong> since version %2$s! Use %3$s instead.',
						$class,
						$version,
						'<code>__construct()</code>'
					),
					E_USER_DEPRECATED
				);
			}
		}
	}
}