I wonder how this compares with Carbon -> C++ [0].

Carbon is (was?) a fantastic proposal, but not sure if it has lost steam since it was introduced or how well it is being adopted (be it inside Google or outside)?

Being able to incrementally/interchangeably use/call existing C++ code (and vice versa) seems like a great design choice (in Carbon) without having to introspect the actual generated code.

Not sure how easy it is to get the cppfront-generated C++ to bridge with existing C++ code (and vice versa)?

[0] https://github.com/carbon-language/carbon-lang