Regression with Narrowing (Test Cases) #20600
Description
I had been working on narrowing in #20277.
After #20275 was fixed in #20492, I merged and ran some test cases.
Here are some test cases that I wrote from that one that the new version fails on:
[case testMultipleTypeEqualsCheck]
from typing import Any
x: Any
y: Any
if type(x) == type(y) == int:
reveal_type(y) # N: Revealed type is "builtins.int"
reveal_type(x) # N: Revealed type is "builtins.int"
z: Any
if int == type(z) == int:
reveal_type(z) # N: Revealed type is "builtins.int"
[case testTypeEqualsCheckUsingImplicitTypes]
from typing import Any
x: str
y: Any
z: object
if type(y) is type(x):
reveal_type(x) # N: Revealed type is "builtins.str"
reveal_type(y) # N: Revealed type is "builtins.str"
if type(x) is type(z):
reveal_type(x) # N: Revealed type is "builtins.str"
reveal_type(z) # N: Revealed type is "builtins.str"
[case testTypeEqualsCheckUsingDifferentSpecializedTypes]
from collections import defaultdict
x: defaultdict
y: dict
z: object
if type(x) is type(y) is type(z):
reveal_type(x) # N: Revealed type is "collections.defaultdict[Any, Any]"
reveal_type(y) # N: Revealed type is "collections.defaultdict[Any, Any]"
reveal_type(z) # N: Revealed type is "collections.defaultdict[Any, Any]"
[case testUnionTypeEquality]
from typing import Any, reveal_type
# flags: --warn-unreachable
x: Any = ()
if type(x) == (int, str):
reveal_type(x) # E: Statement is unreachable
class X: x = 1
class Y: y = 1
class Z(X, Y): ...
z = Z()
x: X = z
y: Y = z
if type(x) is type(y):
reveal_type(x) # N: Revealed type is "__main__.<subclass of "__main__.X" and "__main__.Y">"
reveal_type(y) # N: Revealed type is "__main__.<subclass of "__main__.Y" and "__main__.X">"
x.y + y.x
if isinstance(x, type(y)) and isinstance(y, type(x)):
reveal_type(x) # N: Revealed type is "__main__.<subclass of "__main__.X" and "__main__.Y">"
reveal_type(y) # N: Revealed type is "__main__.<subclass of "__main__.X" and "__main__.Y">"
x.y + y.x
[case testTypeEqualsCheckUsingIsNonOverlapping]
# flags: --warn-unreachable
from typing import Union
y: str
if type(y) is int: # E: Subclass of "str" and "int" cannot exist: would have incompatible method signatures
y # E: Statement is unreachable
else:
reveal_type(y) # N: Revealed type is "builtins.str"
[case testTypeEqualsMultipleTypesShouldntNarrow]
# make sure we don't do any narrowing if there are multiple types being compared
# flags: --warn-unreachable
from typing import Union
x: Union[int, str]
if type(x) == int == str:
reveal_type(x) # E: Statement is unreachable
else:
reveal_type(x) # N: Revealed type is "builtins.int | builtins.str"Please let me know if I can contribute to #20598 (or any other parts of this feature).