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NamedTuple triggered mypy error inside a class #7531
Description
from typing import NamedTuple
class A:
def __init__(self) -> None:
self.tuple2 = NamedTuple('x', [('y', str), ('z', bool)])
def run2(self) -> NamedTuple:
return self.tuple2(y='y', z=True)
print(A().run2())The script will trigger "NamedTuple" not callable mypy(error), not sure if this is as expected
Reference:
https://mypy.readthedocs.io/en/latest/kinds_of_types.html#named-tuples
Tested with Python37 and mypy==0.701
Activity
JelleZijlstra commentedon Sep 19, 2019
This is expected (although the error message could be better). The NamedTuple constructor isn't meant to be used at runtime in a class constructor; instead you should define your NamedTuple type in the module scope.
JukkaL commentedon Sep 20, 2019
It would be better if mypy would at least tell that defining a NamedTuple type as an attribute is not supported.
AFanaei commentedon Oct 7, 2019
@JukkaL
I created a test to fix this issue but the test causes some exceptions:
could you give some hint what is wrong?
JukkaL commentedon Oct 8, 2019
@AFanaei Try adding
[builtins fixtures/list.pyi]to the end of the test case.Produce error when NamedTuple is assigned to attribute
Produce error when NamedTuple is assigned to attribute
Produce error when NamedTuple is assigned to attribute (#7662)