Worked on the php/php-src repository to address a bug in the ReflectionProperty::isReadable() method, ensuring that references returned by the __isset magic method are properly unwrapped. This fix improved the reliability of reflection-based tooling and dynamic property checks in PHP internals. The approach involved C programming to modify the core logic and the addition of a regression test to verify correct behavior when __isset returns a reference, preventing future regressions. The work demonstrated a focus on robust unit testing and careful handling of language internals, contributing to more predictable and maintainable property visibility checks within the PHP codebase.