BSK-E0053 error

assert_type() type mismatch

assert_type(expr, Type) is a static-analysis directive that verifies the inferred type of expr equals Type. When the resolver can determine both sides and they do not match, this rule emits an error.

from typing import assert_type

def f(a: int | str) -> None:
    assert_type(a, int)  # E — int | str is not int

How to handle it

Every rule is on by default — strict is the default, not a cage. You can dial BSK-E0053 down per-file or per-path from your editor or pyproject.toml, or fix the code so it type-checks. See the Type System rules and the complete diagnostic reference.

Canonical URL: https://www.basilisk-python.dev/errors/BSK-E0053