Passing self to a generic function that accepts Self
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bug
topic-self-types
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
- PR metrics pending
Description
from typing import Generic, Self, TypeVar
T = TypeVar('T')
class X(Generic[T]):
def f(self, t: T) -> None:
pass
class Y:
def g(self) -> None:
X[Self]().f(self) # error: Argument 1 to "f" of "X" has incompatible type "Y"; expected "Self" [arg-type]
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
Use the Python reproduction in the issue as the entry point and run mypy against it to confirm the arg-type diagnostic. Trace how Self is resolved for X[Self] and how the call to f is checked; done means this valid-looking call is accepted without the incompatible-type error, with a regression test covering the case.
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