Description
I am looking at the current rules in https://github.com/CarliJoy/intersection_examples/blob/main/specification.rst#typeddicts, which say that if two TypedDict members of an intersection share the same field with different types, then the intersection contains a field that is a union of those two types.
from typing import TypedDict
class A(TypedDict):
a: int
class B(TypedDict):
a: str
def takes_a(a: A) -> None:
print(a["a"] + 1)
def takes_ab(ab: A & B) -> None:
assert_type(ab["a"], int | str)
takes_a(ab) # legal, A & B is compatible with A
b: B = {"a": "x"}
takes_ab(b) # legal, but throws an error at runtimeA similar hole:
def takes_ab2(ab: A & B) -> None:
ab["a"] = 42 # legal, as ab["a"] is of type int | str
b2: B = {"a": "x"}
takes_ab2(b2)
print(b2["a"]) # now it's an int!Possibly the type of ab["a"] should actually be int & str, not int | str.