(And is what rustls uses)
It was a great experience in the mid-90's, but a modern language in 2016 requires much more that what it offered, hence why I eventually got disappointed with Go's feature set.
I would rather see Ada, SPARK, Swift, Rust, ATS, Idris, F*, Formal Methods or whatever else that ensures that our code runs on top of solid foundations.
In any case, my point still stands: People aren't going to rewrite all that C code. The best we can hope for is for some UB to actually be standardized, so that the sociopaths who write the compilers are reigned in a bit.
Since I know C (1992), I have seen quite a few times people write code to go fast as they can and apply compiler optimization tricks for use cases where it hardly matters.
Also many of the issues regarding UB go back to the early ANSI C days, when it was the wild west of C dialects outside UNIX and no vendor wanted to give up on their own extensions.
As for C and C++ compiler writers view on UB:
C's culture of hyper-optimization is ridiculous. Unfortunately, while Rust may well eat C++'s lunch, there's very little that is competitve with C at the same level of abstraction, so for some work (kernel development, perhaps, embedded systems, definately) it will remain significant for some time, if not outright dominant.
In any case, LSSL can be a heck of a lot safer than OSSL, and, in fact, already is.