How does Rust Achieve Complete Memory Safety as Opposed to C++?

( I'm not trying to start a flame war, this is for a research paper. )

More precisely, C++ has constructs like smart pointers and RAII to make memory management simpler.

And yet , many C++ projects like the android kernel ( according to google ) are apparently still riddled with memory safety issues and most games still encounter numerous memory leaks.

However, as of now, rust seems to eliminate these issues, so how exactly does it do it?