You can just drop this part.

If we're going to disallow passing a mysqli instance to mysqli_thread_safe(), we should also mark the associtated mysqli::thread_safe() as static. Same for mysqli::get_client_info(). See also https://bugs.php.net/78790.

@cmb69 Thank you for your help on the issue. Does it need any discussion in order to declare them static or can I go ahead and create a PR?

I think this should be discussed, at least. After all, even the documentation states that mysqli_get_client_info() is supposed to be called with a mysqli argument, so this might be quite some BC break. :(

If it's documented, let's go with what the docs say it should be.

Problem: if we enforce the mysqli parameter, likely some code which doesn't pass would break. Also docs are inconsistent regarding mysqli_get_client_info() and mysqli_thread_safe() (the latter is parameterless). This is rather messy :(