False positive no-member for NamedTuple._replace()

[ppentchev]

Steps to reproduce

1. Save the attached file as ntuple.py and run pylint on it. ntuple.txt

"""A test case for a possible pylint bug."""

from typing import List, NamedTuple


class Lines(NamedTuple):
    """A class for storing things."""

    lines: List[str]

    def add_line(self, line: str) -> "Lines":
        """Return an object with the line added."""
        return self._replace(lines=self.lines + [line])


if __name__ == "__main__":
    lines = Lines(lines=[])
    print(repr(lines.add_line("Live long and prosper!")))

Current behavior

************* Module ntuple
ntuple.py:13:15: E1101: Instance of 'Lines' has no '_replace' member (no-member)

(on Python 3.9 it also complains about inheriting from the non-class NamedTuple, but that's a separate, probably already known, issue)

Expected behavior

No diagnostic messages at all.

pylint --version output

pylint 2.6.0
astroid 2.4.2
Python 3.8.6 (default, Sep 29 2020, 13:19:50)
[GCC 10.2.0]