`IndexError` when using `foo()`

[AlexWaygood]

Checklist

• I am confident this is a bug in CPython, not a bug in a third-party project
• I have searched the CPython issue tracker,
  and am confident this bug has not been reported before

CPython versions tested on

3.11, 3.12, 3.13 (main branch or an alpha release)

Operating systems and architectures tested on

Windows

A clear and concise description of the bug

This raises IndexError:

foo()