(🐞) False error "Expression type contains Any" from constructor when constructor isn't used
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bug
topic-disallow-any
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
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Description
class A:
def __init__(self, foo): ...
@staticmethod
def foo() -> None: ...
A.foo() # error: Expression type contains "Any" (has type "Type[A]")
Despite the fact that A can be called as (Any) -> Any, the constructor isn't being referenced or invoked here.
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 linked mypy playground reproduction using Python 3.10 and the disallow-any-expr flag. Trace how the type of A.foo is checked when A has an unannotated constructor. Done means the shown call no longer reports a false "Expression type contains Any" error, with a regression test covering the example.
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Assessment
- Tech stack
- python
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 42/100