Allow type aliases be used as variables

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#327 2 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
devtools

Research direction

Start with lib-python/3.2/shutil.py and reproduce the type-checking result for the WindowsError alias example. Trace how mypy handles a type alias in an assignment and exception-handling flow; done means the shown code is accepted without weakening unrelated type checks.

Written by the indexing model from the issue text.

Description

bug false-positive priority-2-low

It would sometimes be useful to be able to use at least simple type aliases as variables. For example, this code should probably be accepted:

import typing
try:
    x = WindowsError
except NameError:
    x = None

This affects lib-python/3.2/shutil.py.

Dominant language
Python
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Merged PRs (30d)
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