Doesn't work on PHP 5.6

Author: sad-spirit

HTML/QuickForm2/Element/Hierselect.php

@@ -332,7 +332,8 @@ private function _generateInlineScript()
     {
         // we store values and options with id of first select rather than with
         // the element's name since the former has more chances to be unique
-        $selectId = (reset($this->elements) ?: $this)->getId();
+        $element  = reset($this->elements) ?: $this;
+        $selectId = $element->getId();
         $cr       = self::getOption(self::OPTION_LINEBREAK);
         $js       = "qf.elements.hierselect.defaults['{$selectId}'] = " .
                     HTML_QuickForm2_JavascriptBuilder::encode($this->_values) . ";{$cr}";