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dict(zip()) and itertools.product #3884
Description
I think I've noticed a tiny bug.
Python 3.6.1
mypy 0.521
from typing import Tuple, Dict
from itertools import product
# works fine
XY_1: Dict[str, Tuple[int, int]] = dict(zip('abcd', product(range(2), range(2))))
# {'a': (0, 0), 'b': (0, 1), 'c': (1, 0), 'd': (1, 1)}
# error for this one
XY_2: Dict[str, Tuple[int, int]] = dict(zip('abcd', product(range(2), repeat=2)))
# {'a': (0, 0), 'b': (0, 1), 'c': (1, 0), 'd': (1, 1)}
The dictionaries are the same.
Error output:
mypy_test.py:10: error: Argument 2 to "zip" has incompatible type Iterator[Tuple[int]]; expected Iterable[Tuple[int, int]]
I think that this is not essential. So, just in case.
Thanks for the great product!
Activity
ilevkivskyi commentedon Aug 29, 2017
This is an example of #3541, we currently only support literals via the plugins (no special support for dependent types yet). I will reference this issue there as an example.
JelleZijlstra commentedon Aug 29, 2017
Even if we could be more precise with a plugin here, I think there's a bug in the typeshed stubs for
product(introduced perhaps by @matthiaskramm's python/typeshed#1393): therepeatargument is ignored.ilevkivskyi commentedon Aug 29, 2017
@JelleZijlstra Yes, I think there should be something like several overloads without
repeat, and then one withrepeatthat returnsIterable[Tuple[T, ...]]. Maybe we should open a separate issue at typeshed tracker, and only track the plugin here, what do you think?