In a new post to his site Sammy Kaye Powers shows you how to test unreleased features of PHP using a pull request related to a RFC that's officially been proposed.
We'll be discovering and testing a completely unreleased feature of php-src from an RFC that's still under discussion.
If you've ever wanted to be ahead of the curve of PHP features or you've just wanted to contribute back to PHP internals, testing an unreleased feature from an RFC is a fun and educational way to do so.
He uses the typed properties RFC in his example (allowing the addition of types to class properties). He then walks through the checkout of the PHP source, grabbing the pull request for the RFC and compiling PHP with the new code in place. He shows an example of a script that makes use of this new feature and tries it out. Finally, he covers how to run tests on this new version and some suggestions on adding typed properties to real-world projects.