Comment by tialaramex

Rust safe subset doesn't have UB. At all. So long as you never write the "unsafe" keyword you're fine, the compiler will check you are obeying all of the language rules at all times.

Whereas in C, oops, sorry, you broke a rule you didn't even know existed and so that's Undefined Behaviour left and right. Some of it you could argue falls into the category you're describing, where in a better world it should have been made Implementation Defined, not UB, and too bad. However lots of it is just because the language was designed a very long time ago and prioritized ease of implementation.

If you wish the language was properly defined, you should use (safe) Rust. If you just wish that when you write nonsense the compiler should somehow guess what you meant and do that, you're not actually a programmer, find a practice which suits you better - take up knitting, learn to paint, something like that.