False uninitialized-instance-variable for annotated Enum payloads #5277

Describe the bug

Enum initializes _value_ when constructing its members. An explicit _value_ annotation should not require a handwritten initializer.

Reproduced with Pyrefly 1.4.0 and CPython 3.14.8 on macOS. Pyrefly 1.3.2 accepts the same example under --preset all.

Reproducer

from enum import Enum

class Format(Enum):
    _value_: str
    TEXT = "text"

    def render(self) -> str:
        return self._value_

assert Format.TEXT.render() == "text"

Commands

uvx --from pyrefly==1.3.2 pyrefly check --preset all enum_payload.py
uvx --from pyrefly==1.4.0 pyrefly check --preset all enum_payload.py
python enum_payload.py

The runtime assertion passes. The configuration only sets preset = "all" and python-version = "3.14".

Pyrefly 1.4.0 output

Instance attribute `_value_` is declared but never initialized [uninitialized-instance-variable]

Mypy 2.4.0 (strict, without project plugins) and Pyright 1.1.414 accept this example.