> We're late for C2X, I think,
> so it's probably going to be for C3X.
> If you can make it into C2X it would be nice.
> If not, I'd like to write the paper :-)

     Yeah, even though nonnull is small, there's almost nothing that
can be done simply in C thanks to existing practice. GCC has QUITE a
few people who are upset by the warnings produced by [[gnu::nonnull]]
among other things, so you'd have to be very careful in crafting the
semantics to make people a little less annoyed at a version of it that
makes it into the standard. But, given that this would be a C2Y or C3x
sort of deal, I think there's plenty of time to get it.

     Best of luck! Let me know if you need any help. :D

Best Wishes,
JeanHeyd