Assigning an iterator to the type hint `collections.abc.Hashable` gets error even though an iterator is hashable
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Description
*Memo:
- Python 3.14.0
- mypy 1.18.2
- mypy test.py
- Windows 11
An iterator is hashable as shown below:
print(hash(iter([0, 1, 2])))
# 127553071047
But assigning an iterator to the type hint collections.abc.Hashable gets the error as shown below even though an iterator is hashable:
from collections.abc import Hashable
v: Hashable = iter([0, 1, 2])
# Error
error: Incompatible types in assignment (expression has type "Iterator[int]", variable has type "Hashable")
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First steps
- Read the whole issue, then the project's contributing guide.
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Research direction
Start by reproducing the assignment in test.py with Python 3.14.0 and mypy 1.18.2, then trace how mypy models Iterator[int] and collections.abc.Hashable. Done means the reported mismatch is resolved or its intended static behavior is established with a regression test.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 42/100