Type issue not found in function call

[maxnoe]

Running mypy on this small code example:

def build_greeting(name: str = 'World') -> str:
    return f'Hello {name}!'


def greet(name='World'):
    print(build_greeting(name))


if __name__ == '__main__':
    greet('foo')
    greet(4)

results in it reporting "no issues". Although greet and thus build_greeting are called with an integer.

[emmatyping]

Hi, since greet isn't annotated it isn't checked, please see https://mypy.readthedocs.io/en/stable/common_issues.html#no-errors-reported-for-obviously-wrong-code

[maxnoe]

This also shows no issue:

from typing import Any


def build_greeting(name: str = 'World') -> str:
    return f'Hello {name}!'


def greet(name: Any = 'World') -> None:
    print(build_greeting(name))


if __name__ == '__main__':
    greet(4)

So transitive problems don't seem to be checked.

[emmatyping]

Mypy doesn't really do interprocedural analysis like that.