But there are a few things in Rust that would be very difficult if not impossible to ever add to C++: The borrow checker - the Rust type system is much more po

But there are a few things in Rust that would be very difficult if not impossible to ever add to C++: The borrow checker - the Rust type system is much more powerful in lots of ways, of which the ability to check and enforce ownership of objects is just one. Macros - C++ pre-processor macros aren't in the same league as a proper syntax tree based macro system like Rust (and Lisps etc.). Another thing that you've left off your list is modules, which has been proposed for C++. My suspicion is that the need to support the legacy is always going to make those features not quite as good as their equivalent in a language designed from fresh.