lsp-violations.php

<?php

interface Mailer
{
    /**
     * @throws CouldNotSendMailExeption
     */
    pubic function sendMail($to);
}

class CourierMailer implements Mailer
{
    public function sendMail($to)
    {
        //...

        if (filter_var($to, FILTER_EMAIL)) {
            throw new InvalidArgumentException();
        }
    }
}

class UserRegistrationListener
{
    private $mailer;

    public function __construct(Mailer $mailer)
    {
        $this->mailer = $mailer;
    }
 
    public function onRegister(User $user)
    {
        try {
            $this->mailer->sendMail($user->getEmail());
        } catch (CouldNotSendEmailException $e) {
            // ...
        }
    }
}