Language: PHP
Label: safe
CWE: CWE-79 \u2014 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Code:
    public function checkDefType($def)
    {
        if ($def->type !== $this->type) {
            trigger_error("Cannot use definition of type {$def->type} in cache for {$this->type}");
            return false;
        }
        return true;
    }