Spurious F841 in exception even when referenced by locals()

[jaraco]

I recently upgraded to flake8 3.6 and pyflakes 2.0.0, and now I'm getting failures in code where locals() contains the only reference to a variable in the namespace.

draft $ cat > f841fail.py
try:
    raise ValueError()
except Exception as e:
    print(locals())
draft $ python f841fail.py
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x10138c710>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, '__file__': 'f841fail.py', '__cached__': None, 'e': ValueError()}
draft $ flake8 --version
3.6.0 (mccabe: 0.6.1, pycodestyle: 2.4.0, pyflakes: 2.0.0) CPython 3.7.1 on Darwin
draft $ flake8 f841fail.py
f841fail.py:3:1: F841 local variable 'e' is assigned to but never used
draft $ pip install -U pyflakes
Requirement already up-to-date: pyflakes in /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages (2.0.0)

In other blocks, the use of locals() prevents F841 from being triggered. It should in exception blocks too.

[asottile]

#333 and #343 appear to aim to fix this

[jaraco]

Indeed, this looks like a duplicate report.