Quoted type name not actually valid as base class

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#1,685 1 comment 0 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
compilers

Research direction

Start by reproducing the two-class example from the issue and trace the type-checking entry point that accepts the quoted base class. Compare the accepted result with Python's runtime behavior, then add a regression test showing that the invalid base class is rejected.

Written by the indexing model from the issue text.

Description

bug priority-2-low

Mypy accepts the following program, but it's actually an error at runtime (even if the lines are reversed).

class A('B'): pass
class B: pass

Sort of similar to #686, but this bug probably has a simple local fix.

Dominant language
Python
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Forks
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Avg merge
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Merged PRs (30d)
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