Yeah, so their documentation serves as the authority on how you're supposed to write your code for it to be "correct D" or "correct Rust". The compiler implementors write their compilers against the documentation (and vice versa). That documentation is clear on these things.

In C, the ISO standard is the authority on how you're supposed to write your code for it to be "correct C". The compiler implementors write their compilers against the ISO standard. That standard is not clear on these things.