Using not yet defined variables is allowed

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#2,788 2 comments 2 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
devtools

Research direction

Reproduce both Python snippets and confirm that mypy emits no error for the use-before-definition cases. Trace the type-checking path for augmented assignment and annotated assignments, then add regression coverage showing that each undefined-variable use is rejected.

Written by the indexing model from the issue text.

Description

bug priority-2-low topic-runtime-semantics topic-variable-scope

This might be the same issue as #937 but this raises no errors:

s += 1
s: int = 0

or

x: int
x += 1
Dominant language
Python
Stars
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Forks
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Avg merge
1d 18h
Merged PRs (30d)
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