I wonder if xhpast can be ditched. Eg:
For linters, use something off-the-shelf such as phpcs (https://github.com/squizlabs/PHP_CodeSniffer)
For diviner parsing of PHP code, I look at the class documentation (eg https://we.phorge.it/book/libphutil/class/ArcanistConduitCallFuture/) and question as to whether this provides anyone with any benefit.

I've created R10 PhorgeIt Extension for this, with a little bit of content. I'll load it to the server shortly.