python / python/mypy

no error when unhashable object in dict

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#11,465 2 comments 0 reactions 0 assignees View on GitHub

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feature topic-runtime-semantics
Dominant language
Python
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Description

from typing import Hashable


class SomeDClass:
    __hash__: None = None  # type: ignore

d = {
    [1]: 1,  # SUS ALERT! fails at runtime
    SomeDClass(): 2,  # SUS ALERT! fails at runtime
}

Is this an issue with the stubs?

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Research direction

No files or tests are named. Start by reproducing the snippet with mypy and determine whether unhashable dictionary keys are expected to produce a diagnostic; done means establishing whether this is a stub issue or a type-checker behavior issue and documenting the expected result.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
devtools
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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