alt Hacker NewsI don't think it is available no, and it's the first time I heard about such an idea. Thinking on it, this would allow such cursed code (love that :D). I'll put it up for discussion in the Discord as I'm interested in hearing whether `.defaultof` is a good idea or not.
One application of such a feature would be something like a "cligen.c3" (like the Nim https://github.com/c-blake/cligen or its /python/cg.py port or etc.). Mostly it just seems a more complete signature extraction, though. Any other kind of documentation system might benefit.