I say this about C every day.

Yeah I dislike it. Why are we babyducking sepples attributes? And what I assume to be namespace accessors? Why are logical assertions enclosed in backticks? I "get it", because it's actually kind of difficult to make a backwards compatible derivative of C that doesn't devolve into glyph soup, but this has a massive frankengrammar stink to it. The proof language is eyebrow raising to say the least.

What's terrible about the syntax? Using "[[require/ensure/invariant/proof/assert/etc.]]" is actually pretty neat.

And given that almost all C programmers are also C++ programmers, no mere syntax can faze us :-)