Example

def a(b=float("inf")): ... # True Negative
def c(d=slice(None)): ... # False Positive, as slice() is immutable

There is also the semi-related corner case of def e(f: slice = dict()): .... This is clearly erroneous code, but it is incorrectly flagged as violating B008, despite the docs saying "Parameters with immutable type annotations will be ignored by this rule". (e.g., def g(h: int = dict()): ..., does not trigger B008)

see also: docs.python.org > builtins > slice

Version

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