Using a function named cast (shadows a newish builtin) leads to somewhat confusing errors. For the test file:

from something import cast
# same with `def cast(s): pass`

abc = "123"
cast(f"tuv {abc} xyz")

We get the following unexpected results:

$ ruff tmp.py 
Found 2 error(s).
tmp.py:5:6: F722 Syntax error in forward annotation: ` xyz`
tmp.py:5:6: F821 Undefined name `tuv`

I'm not quite sure what the best resolution is, maybe a warning on imports/defs that shadow cast?