Class definition scope using walrus assignment operator raises [name-defined] error

Bug Report

When using the assignment operator (aka "walrus") inside the class definition scope, I get a [name-defined] error.

To Reproduce
https://mypy-play.net/?mypy=latest&python=3.11&gist=367470bba328790329e68ce08bd7eb59

class TestTuple:
    t = (a := 1, a)


class TestExpression:
    (b := 2, b)


def add(x: int, y: int):
    return x + y


class TestAdd:
    result = add(c := 3, c)


class TestOverride:
    d = add(d := 4, d)


TestTuple.a      # output: 1
TestTuple.t      # output: (1, 1)
TestExpression.b # output: 2
TestAdd.c        # output: 3
TestAdd.result   # output: 6
TestOverride.d   # output: 8

Expected Behavior
I expected mypy to not raise any error as these all execute in python.

Actual Behavior

main.py:2: error: Name "a" is not defined  [name-defined]
main.py:6: error: Name "b" is not defined  [name-defined]
main.py:14: error: Name "c" is not defined  [name-defined]
main.py:18: error: Name "d" is not defined  [name-defined]
Found 4 errors in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.6.1
• Mypy command-line flags:
• Mypy configuration options from mypy.ini (and other config files):
• Python version used: 3.11

Commencez par la reproduction mypy-play liée et les exemples Python 3.11 de l’issue, puis suivez la manière dont les affectations avec l’opérateur walrus au niveau de la classe sont analysées. Le travail est terminé lorsque les exemples signalés passent la vérification de types sans les quatre erreurs name-defined, tout en conservant les valeurs inférées indiquées.