Most of what this offers can be replicated in Java with properly set up build-time code gen plugins and Lombok (or a bunch of standard annotation processors).

Most of what this offers can be replicated in Java with properly set up build-time code gen plugins and Lombok (or a bunch of standard annotation processors). The remaining operator overloading and naive C-style preprocessor are from the wish list of someone who never had to understand or maintain software using those. Finally, reliance on Javac's internals guarantees brittleness across JDK updates. This is much more than just a plugin, it should provide it's own compiler, even if 95% would be lifted from an existing Javac implementation. Hard pass.