Add Stringable interface support in Validator.php

Author: spaze

src/Forms/Validator.php

@@ -12,6 +12,7 @@
 use Nette;
 use Nette\Utils\Strings;
 use Nette\Utils\Validators;
+use Stringable;
 use function array_map, count, explode, in_array, is_array, is_float, is_int, is_object, is_string, preg_replace, preg_replace_callback, rtrim, str_replace, strtolower;
 use const UPLOAD_ERR_INI_SIZE;
 
@@ -58,6 +59,9 @@ public static function formatMessage(Rule $rule, bool $withValue = true): string
 		if ($message instanceof Nette\HtmlStringable) {
 			return $message;
 
+		} elseif ($message instanceof Stringable) {
+			return (string)$message;
+
 		} elseif ($message === null && is_string($rule->validator) && isset(static::$messages[$rule->validator])) {
 			$message = static::$messages[$rule->validator];