Interestingly for frozenset we have tight typing for the Iterable generic. That might be because it's covariant, so I wonder if we could get away with that here as well.

Yeah - we just had Any for set so wasn't totally sure. Let me give that a try.

Interestingly for frozenset we have tight typing for the Iterable generic. That might be because it's covariant, so I wonder if we could get away with that here as well.

Actually, I think we want Any, frozenset rejects this, which seems overly strict:

keys = frozenset(["foo", "bar", "baz"])
keys.isdisjoint({"baz", "qux"})
keys.isdisjoint(["baz", "qux"])
# Rejects
keys.isdisjoint([1, 2])

Unless we wanted to use overloading to say that we know for certain isdisjoint returns True if the there's no intersection between the types.

Sounds good @hauntsaninja, @JelleZijlstra!

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉