Sorry, I used imprecise language. What you propose is fine. On Feb 24, 2018 09:54, "Eric V. Smith" <report@bugs.python.org> wrote: > > Eric V. Smith <eric@trueblade.com> added the comment: > > Note that this class (from the test suite) will now raise an exception: > > @dataclass(unsafe_hash=True) > class C: > i: int > def __eq__(self, other): > return self.i == other.i > > That's because it has a __hash__, added when __eq__ is defined. I think > we're better off with the rule being: > > If unsafe_hash=True, raise an exception if __hash__ exists and is not > None. Otherwise add __hash__. > > That's how it used to be with hash=True (in 3.70b1). > > Or is that what you meant by "but if a __hash__ method is present, an > exception is raised"? Notice the word "method", instead of attribute. > > ---------- > > _______________________________________ > Python tracker <report@bugs.python.org> > <https://bugs.python.org/issue32929> > _______________________________________ >