Not that it really matters to this issue, but here's how dataclasses and attrs deal with this:

dataclasses has the same issue, via make_dataclass().

attrs gives a syntax error with your field names, but interestingly this succeeds:

>>> Foo = attr,make_class('Foo', ['a', 'b', 'a'])
>>> Foo(1, 3)

I'll open a corresponding issue for dataclasses.
Foo(a=1, b=3)