Support intersection types (PHP 8.1+ / ported from v2 to v3)

[bzikarsky]

See #195 for details.

Unrelated: I fixed an E_DEPRECATED on 8.1 in RejectedPromiseTest (Deprecated: Exception::__construct(): Passing null to parameter #1 ($message) of type string is deprecated in /code/tests/Internal/RejectedPromiseTest.php on line 40) - Are you fine with adding this in an additional commit to the PR or do you want to have a separate PR (and more rebase action)?

[clue]

@bzikarsky Thank you for taking over and porting this also to Promise v3! 👍

The changes LGTM, but I've noticed some potential to simplify this given we can finally(!) rely on more recent PHP features (#149). Can you look into this?

[clue]

Unrelated: I fixed an E_DEPRECATED on 8.1 in RejectedPromiseTest (Deprecated: Exception::__construct(): Passing null to parameter #1 ($message) of type string is deprecated in /code/tests/Internal/RejectedPromiseTest.php on line 40) - Are you fine with adding this in an additional commit to the PR or do you want to have a separate PR (and more rebase action)?

@bzikarsky I can indeed see the same error on PHP 8.1 (#199) and you're right that this seems to be unrelated to this PR, so perhaps better file this as a separate PR?

[bzikarsky]

Thanks @clue for going over it.

Those 7.1 related simplifications make sense and I can also supply that extra fix in a separate PR. It may have to wait until Monday though - depending on what my family is up to over the weekend. 🙂

[bzikarsky]

Improvements are in. 🙂

Unrelated: I fixed an E_DEPRECATED on 8.1 in RejectedPromiseTest (Deprecated: Exception::__construct(): Passing null to parameter #1 ($message) of type string is deprecated in /code/tests/Internal/RejectedPromiseTest.php on line 40) - Are you fine with adding this in an additional commit to the PR or do you want to have a separate PR (and more rebase action)?

@bzikarsky I can indeed see the same error on PHP 8.1 (#199) and you're right that this seems to be unrelated to this PR, so perhaps better file this as a separate PR?

PR is at #210.

[clue]

@bzikarsky Thanks for the update, changes LGTM, keep it up!