We have a ton of GC languages already. Rust is unique for being able to do a lot of things very safely, but also fast because it does not require a GC.
Being able to generate fast code doesn't imply not having a GC.
It is all a matter how it is implemented and the additional language features for manual types and control of allocations, and how good the compiler backend is transforming all that AST information into actual code.
Something like Modula-3, Active Oberon, System C#, Eiffel, D and so forth.
