> Rust should integrate easily with C++ code

The day that Rust manages to have always up to date Qt bindings that do not force you to make compromises compared to the C++ API, I think the C++ support will be at a comfortable level. Right now there are fresh efforts in the Rust and Haskell camps to solve this cleanly in a modern way. It would certainly help if the consumption of C++ APIs via llvm (which is used a lot byt Rust) was made a first class feature like you can import and export C APIs. Exporting C++ classes is a whole different story and may not map in any reasonable way to Rust modules or crates.