B018: Find more constants w/o assign

[kasium]

This check now also finds:

• numbers (ints, float, complex)
• lists
• sets
• dicts
• binary strings
• joined strings (f-strings)
• name constants (True, False, None)

This is part 1 of #200 . The second part will enable the check for modules

[cooperlees]

SGTM - This makes b018 much more complete. Thanks for the efforts. /me wonders how many weird typos across the world this will pickup.

I'll look to release over the weekend / Monday (west coast USA) time ...

[asottile]

I think this still misses a few things, such as this subtle bug:

def f():
    f"string"

[kasium]

@asottile thanks for your feedback. If I'm not wrong, JoinedStr is catched:
https://github.com/PyCQA/flake8-bugbear/blob/master/bugbear.py#L589

And a f-string w/o parameter is catched in pyflakes I guess

[asottile]

it's only caught at body positions 1+

[kasium]

Ah, yes. You are right.

However, I'm not sure if this should be covered here. It's not recommended to use " as the docstring and to find out which quotes where used, I guess tokens are needed. Therefore, I see this more in https://pypi.org/project/flake8-docstrings/.

@cooperlees what do you think?

[asottile]

no all I'm suggesting is to extend the check to 0+ instead of 1+ and add an exception for Str at 0

[kasium]

Sorry, that was clear 😄. Let me open a PR. That's a great idea!