I suppose you can make that assertion by moving the goalposts. But Rice's theorem specifically addresses such behavior: all turing machines are inherently unde

I suppose you can make that assertion by moving the goalposts. But Rice's theorem specifically addresses such behavior: all turing machines are inherently undecidable for all but trivial cases. You can well argue that Rust may be better than C++ in some dimension, just as others can argue that those qualities have an unreasonable or intractable cost (note that about 20% of all crates resort to `unsafe`). But your blanket assertion is not even supported by the reference you made. Also the user is free to tell a C++ compiler to reject programs that use many sorts of undefined behavior, though indeed nobody would claim that any current compiler can identify all such cases. But Rice's theorem says that no Rust compiler could either.