Walrus operator + annotation can cause F821 in version 3.3.0

[jbjd]

In order to type hint a variable used in a walrus expression, I put the type hint outside of the expression like in the following example (test.py):

a: int
if a := 3:
    print(a)

print(a)

Variable "a" is defined in both places

$ python3 test.py
3
3

In pyflakes version 3.2.0 this produced no errors

pip install flake8==7.1.2 pyflakes==3.2.0

$ flake8 test.py

In pyflakes version 3.3.0 this produces F821 even though "a" is defined

pip install flake8==7.2.0 pyflakes==3.3.0

$ flake8 test.py
test.py:3:11: F821 undefined name 'a'
test.py:5:7: F821 undefined name 'a'

I am on Windows with Python version 3.12.8

[sigmavirus24]

Thanks for reporting and fixing!