[New-bugs-announce] [issue39300] dataclasses non-default argument follows default argument

[lijok]

New submission from lijok <egecas at live.co.uk>:

from dataclasses import dataclass


@dataclass
class A:
    PARAM: int


@dataclass
class B(A):
    ARG: int
    PARAM: int = 1

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\dataclasses.py", line 1021, in dataclass
    return wrap(cls)
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\dataclasses.py", line 1013, in wrap
    return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen)
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\dataclasses.py", line 927, in _process_class
    _init_fn(flds,
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\dataclasses.py", line 503, in _init_fn
    raise TypeError(f'non-default argument {f.name!r} '
TypeError: non-default argument 'ARG' follows default argument

----------
components: Library (Lib)
messages: 359782
nosy: eric.smith, lijok
priority: normal
severity: normal
status: open
title: dataclasses non-default argument follows default argument
type: behavior
versions: Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39300>
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