[1.18 regression (typeshed)] ANY from unittest.mock is now reported as incompatible type in 1.18.1 #19841
Description
After upgrading to mypy 1.18.1, we started getting a new type error that was not present in 1.17.1.
Example
from unittest.mock import ANY
def func(param: str | None) -> None:
pass
func(param=ANY)Error (with 1.18.1)
error: Argument "param" to "func" has incompatible type "_ANY"; expected "str | None"
This code is obviously not meaningful by itself, but using ANY without an error was very helpful for testing when comparing complex structures.
Questions
- Is this a deliberate change in behavior or a regression?
- If this is now the expected behavior, would you recommend creating a TypedAny helper for tests, or is there a better workaround?
This seems like a breaking change for test code that relies on ANY being assignable to any type.