If I understand correctly, one of the recent cool generative AI-assisted results is actually supposed to have closed this problem, complete with a Lean proof!

https://arxiv.org/abs/2608.29592

I think language designers in general have realized that there's nothing particularly virtuous about a programming language with a syntax that's hard to parse.

Go and Rust (and Pascal) have cleaned up C's awful legacy enough that they're parseable with LL(X) parsers that don't have scary corner cases or polynomial behavior.