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mypy not checking if calling passing a value of type Any to a function expecting some other type #16563
Closed as not planned
Description
Bug Report
(A clear and concise description of what the bug is.)
To Reproduce
from typing import Any
class Foo:
pass
def func(foo: Foo) -> None:
pass
def main() -> None:
x: Any = 1
func(x)Expected Behavior
I would expect that mypy would complain when calling func() with a parameter of type Any while func expects Foo.
Actual Behavior
$ mypy --version
mypy 1.7.1 (compiled: yes)
$ mypy --strict test.py
Success: no issues found in 1 source file
$
Your Environment
- Mypy version used:
- Mypy command-line flags:
- Mypy configuration options from
mypy.ini(and other config files): - Python version used:
Activity
erictraut commentedon Nov 25, 2023
Mypy is doing the right thing here. This is how
Anyworks in the Python static type system. It's literally compatible with any other type. When you useAny, you're effectively telling the type checker "don't emit any type violations here, I know what I'm doing". For more details, refer to this section in PEP 484.gjcarneiro commentedon Nov 25, 2023
That is unfortunate, because the Any comes from a sqlalchemy model. I wish we had a different kind of type similar to Any, like Unknown, to annotate when we don't know what is the type of something.
But OK, thanks for indulging my question anyway. I have to investigate how to deal with this. Maybe the nuclear option disallow_any_expr is the way to go :/
AlexWaygood commentedon Nov 25, 2023
If you have a variable that is inferred as
Any, but you'd like to enforce strict typechecking on that variable until the type of the variable has been manually narrowed, consider usingtyping.castto convert the type of the variable toobject, e.g.