weird idea for extending TypeError and having richer 'types' in php

rich_types.php

<?php
// experiment with 'rich types' in php?

class RichTypeError extends TypeError
{
    // maybe customize this
}

class _email
{
    private $email;

    public function __construct(string $email)
    {
        if ((bool)preg_match('/.*@.*/', $email) === false) {
            throw new RichTypeError('not a valid email');
        }

        $this->email = $email;
    }

    public function __toString()
    {
        return $this->email;
    }
}

class _hostname
{
    private $hostname;

    public function __construct(string $hostname)
    {
        $pattern = '/(?:[_\p{L}0-9][-_\p{L}0-9]*\.)*(?:[\p{L}0-9][-\p{L}0-9]{0,62})\.(?:(?:[a-z]{2}\.)?[a-z]{2,})/';

        if ((bool)preg_match($pattern, $hostname) === false) {
            throw new RichTypeError('not a valid hostname');
        }
    }

    public function __toString()
    {
        return $this->hostname;
    }
}

// example of extending the _hostname validation type
class _my_mailserver extends _hostname
{
    private $mailserver;

    public function __construct(string $mailserver)
    {
        parent::__construct($mailserver);

        if ((bool)preg_match('/myserver.com$/', $mailserver) === false) {
            throw new RichTypeError('not a valid mailserver');
        }

        $this->mailserver = $mailserver;
    }

    public function __toString()
    {
        return $this->mailserver;
    }
}

class _api_options
{
    private $options;

    public function __construct(array $options = [])
    {
        if (empty($options) === false && array_key_exists('auth', $options) === false) {
            throw new RichTypeError('api options missing \'auth\' key.');
        }

        $this->options = $options;
    }

    public function __toArray()
    {
        return $this->options;
    }
}

// this example is dumb
class Email
{
    private $address;

    // now we can typehint against these 'rich string' types instead of string
    public function __construct(_email $address, _my_mailserver $mailserver, _api_options $apiOptions = null)
    {
        $this->address = $address;
        $this->mailserver = $mailserver;
        $this->apiOptions = $apiOptions; // dumb, just trying to use the rich array example
    }

    // do stuff
} 

// all of this should pass
$address = new _email('[email protected]');
$mailserver = new _my_mailserver('mail.foo.myserver.com');
$options = new _api_options(['auth' => 'foo']);
$Email = new Email($address, $mailserver);
var_dump($Email);

// this will all fail
$address = new _email('asdf'); // throws RichTypeError
$mailserver = new _my_mailserver('example.com'); // throws RichTypeError
$options = new _api_options(['foo' => 'bar']); // throws RichTypeError
$Email = new Email($address, $mailserver); // won't get here