Incorrect __post_init__ order when KW_ONLY used

[NeilGirdhar]

from dataclasses import dataclass, InitVar, KW_ONLY


@dataclass
class A:
 _: KW_ONLY
 x: InitVar[int]

 def __post_init__(self, x: int) -> None:
 pass


@dataclass
class C(A):
 y: InitVar[str]

 def __post_init__(self, x: int, y: str) -> None: # Correct order.
 super().__post_init__(x)

gives

a.py:19: error: Argument 2 of "__post_init__" is incompatible with supertype "dataclass"; supertype defines the argument type as "str" [override]
 def __post_init__(self, x: int, y: str) -> None:
 ^~~~~~
a.py:19: error: Argument 3 of "__post_init__" is incompatible with supertype "dataclass"; supertype defines the argument type as "int" [override]
 def __post_init__(self, x: int, y: str) -> None: