The `staticProxyConstructor` method of all proxies can have a `self` return type

[Ocramius]

[Ocramius]

After careful inspection, zendframework/zend-code does not allow specifying : self on a return type.

[Ocramius]

Also, cannot be currently done because it would first need https://wiki.php.net/rfc/covariant-returns-and-contravariant-parameters

The test suite tries to proxy over pre-existing proxies, in which case a type restriction on a return type is only possible if variance checks are implemented in php-src.

[Ocramius]

This will be feasible with the new static type in PHP 8

[Ocramius]

No time to get it in 2.11.0, hence moving it to 2.12.0