[ATsch]

Adding a GCC backend for Rust (rust-codegen-gcc) does this already. I do not personally see the point of writing another frontend in C++.

[pjmlp]

Dependency on an existing Rust compiler during GCC bootstrap process.

[ATsch]

You already need an existing C++ compiler to bootstrap GCC though I don't see how this is much different. Plus there is already mrustc as a C++ Rust implementatation specifically designed for bootstrapping.

[pjmlp]

It is one more dependency, not written in C++, and you don't see the difference?