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

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

Merge remote-tracking branch 'upstream/master' into bugfix/pythongh-1…

Merge branch 'master' into bugfix/pythongh-19576-enum-comparison-overlap

@bzoracler

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 ? 🤔

@florianvazelle

@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

Ok, thank you for clarifying that 🙏

Merge branch 'master' into bugfix/pythongh-19576-enum-comparison-overlap

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`comparison-overlap` triggers for string enum members when the member name isn't the same as the comparison value #19576

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comparison-overlap triggers for string enum members when the member name isn't the same as the comparison value #19576

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florianvazelle commented on Oct 14, 2025

bzoracler commented on Oct 14, 2025

florianvazelle commented on Oct 14, 2025

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`comparison-overlap` triggers for string enum members when the member name isn't the same as the comparison value #19576