false "Attempted to reuse member name in Enum definition"

Bug Report

When using an if/else in class scope of an Enum definition, there is a false error "Attempted to reuse member name in Enum definition".

I understand mypy might have an opinion about this pattern, but I noticed there is no equivalent issue for a plain class. So this seems to be an issue specific to Enum that could potentially be relaxed.

To Reproduce

class Foo(Enum):
    if IS_BAZ:
        DISABLED = 16
    else:
        # error: Attempted to reuse member name "DISABLED" in Enum definition "Foo"  [misc]
        DISABLED = 256

class Bar:
    if IS_BAZ:
        DISABLED = 16
    else:
        DISABLED = 256   # (no error)

Expected Behavior

no mypy errors

Actual Behavior

error: Attempted to reuse member name "DISABLED" in Enum definition "Foo"  [misc]

Your Environment

• Mypy version used: 1.8.0
• Python version used: 3.8

Start by running the provided Enum and plain-class reproducer against mypy 1.8.0, then trace the Enum member-name checking path responsible for the duplicate-name diagnostic. Done means the conditional Enum definition produces no mypy errors while duplicate members in genuinely conflicting definitions remain diagnosed.