`comparison-overlap` triggers for string enum members when the member name isn't the same as the comparison value

[bzoracler]

Bug Report, To Reproduce, and Actual Behaviour

If the enum member's name to compare isn't equal to the comparing value, a false positive comparison-overlap is triggered. See mypy Playground:

from enum import Enum

class A(str, Enum):  # Same behaviour if `class A(enum.StrEnum)`
    a = "b"

A.a == "a"  # OK
A.a == "b"  # E: Non-overlapping equality check (left operand type: "Literal[A.a]", right operand type: "Literal['b']")  [comparison-overlap]

Expected Behavior

No errors

Your Environment

• Mypy version used: 1.17, master
• Python version used: 3.12

[florianvazelle]

Hi @bzoracler, for me, this is a true positive, because you are comparing an enum value and a string. IMO, the right thing to do is to compare A.a.value == "b", no ? 🤔

[bzoracler]

@florianvazelle No, as mentioned in the issue title, this is about string enums. String enums (including enum.StrEnum) don't need to access .value to perform str operations or be treated as a str, as explicitly stated in the Python docs:

StrEnum is the same as Enum, but its members are also strings and can be used in most of the same places that a string can be used.

You can try it yourself:

from enum import Enum

class MyStrEnum(str, Enum):
    member = "asdfjkl"

>>> print(MyStrEnum.member == "asdfjkl")
True

[florianvazelle]

Ok, thank you for clarifying that 🙏