nope-wp-trigger-error.php

<?php

/**
 * Trigger Error mini plugin re: escaping.
 *
 * Tested with https://github.com/WordPress/wordpress-develop/pull/5175 checked out.
 *
 * @wordpress-plugin
 * Plugin Name:       Trigger Error mini plugin re: escaping.
 */

add_action(
	'init',
	function() {
		$user_input = $_GET['user_input'];
		if ( ! is_array( $user_input ) ) {
			$message = "\$user_input expects an array, '$user_input' given.";
			wp_trigger_error( __FUNCTION__, $message );
			// wp_trigger_error( __FUNCTION__, esc_html( $message ) );
			// wp_trigger_error( __FUNCTION__, esc_html( esc_html( $message ) ) );
		}
	}
);