Bug ? when dataclass field name == field type

[Cyril]

Hi,
When I create a dataclass with same field.name and field.type and assign a default value to None typehint get lost. I know that it does not respect naming convention but I have reasons to do so in my particular case.

Standard Behaviour

from dataclasses import dataclass
import typing
from typing import Optional, List, Tuple

@dataclass
class NotBuiltIn:
	test: str

@dataclass
class MyDataClass:
	field: Optional[NotBuiltIn] = None

typing.get_type_hints(MyDataClass)

Output:
{'field': typing.Union[__main__.NotBuiltIn, NoneType]}

Type hint get lost (variable name == type name) :

@dataclass
class layers:
	...

@dataclass
class material:
    layers: Optional[layers] = None

typing.get_type_hints(material)

Output:
{'layers': NoneType}

It looks like a bug but is it ?