Loop variable use in closure not considered

Running

flake8==3.9.2
flake8-bugbear==21.4.3
flake8-polyfill==1.0.2
flake8-quotes==3.2.0

on

def main():
    def f(x):
        print(i, x)

    for i in [1, 2, 3]:
        f('HI')

gives me

bugbearbug.py:5:9: B007 Loop control variable 'i' not used within the loop body. If this is intended, start the name with an underscore.

Clearly, i is being used (within the nested function), but bugbear doesn't seem to see it.