Not in a game business, but I could tell you - until Rust is supported (down to debugging) in Visual Studio, there would be no C#/Rust apps, and plenty C#/C++ apps.
Debugging in VS actually works pretty well already, the msvc target generates PDB files. It's what I use when need to attach a debugger to something.
Actual language support would be really nice, though. Hopefully MS are already working on this.