Assignment via `import`

In the following example MyPy complain about local import and does not recognize it as assignment:

from typing import Callable, Optional

def f(callable: Optional[Callable[[float], float]]) -> None:
    if callable is None:
        from math import sqrt as callable  # line 5

    callable(1.5)  # line 7

Output:

t3.py:5: error: Name "callable" already defined on line 3
t3.py:7: error: "None" not callable
Found 2 errors in 1 file (checked 1 source file)

It is not recognized as assignment even for global import:

from typing import Callable, Optional

callable: Optional[Callable[[float], float]] = None
if callable is None:
    from math import sqrt as callable

callable(1.5)  # line 7

Output:

t32.py:7: error: "None" not callable
Found 1 error in 1 file (checked 1 source file)

mypy 0.950 (compiled: yes)
Python 3.9.12

Empieza ejecutando las dos reproducciones inline de Python con mypy 0.950 y compara los errores reportados para las importaciones locales y globales. Rastrea cómo se analizan estos alias de importación y, después, añade cobertura de regresión que demuestre que callable se reconoce después de la importación condicional y que los diagnósticos erróneos han desaparecido.