(🐞) `type[T]` can't be assigned to `Protocol` with `__name__`
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bug
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
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Description
from typing import Protocol
class HasName(Protocol):
__name__: str
class A: ...
t: type[A] = A
n: HasName
n = A # no error
n = t # error: Incompatible types in assignment (expression has type "type[A]", variable has type "HasName") [assignment]
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the reproducer in the issue and trace how mypy checks assignments from a class object and from a variable typed as type[A] against a Protocol containing name. Identify the relevant type-compatibility and Protocol handling paths, then add coverage for both assignments and confirm that their results are consistent.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100