Comment by VWWHFSfQ
I guess I'm wondering what is the point of tail-call optimizations, or even async/await when it's all super slow and bounded by the runtime itself? There are basically no improvements whatsoever to the core cpython runtime. So really what is all this for? Some theoretical future version of Python that can actually use these features in an optimal way?
This TCO is in how the CPython interpreter works, not in making Python itself tail recursive. Some of the C code in the interpreter has been reorganized to put some calls into tail position where the C compiler turns them into jumps. That avoids some call/return overhead and makes the interpreter run a little faster. It's still interpreting the same language with the same semantics.