Warn for incorrect TypeVar usage (with Generics)
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
- PR metrics pending
Description
Feature
Sometimes a user less familiar with more advanced typing concepts will use a TypeVar in a way that doesn't add any typing information.
As an example: def foo() -> T:
I think, basically, anytime a TypeVar appears only 1 time in a function (or class) definition, this should be treated as an error.
Pitch
Code like this seems like an obvious sign the user has misunderstood TypeVar, and a warning should probably be emitted. They either want a normal type, or they missed an annotation somewhere.
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
The issue names no files, tests, or entry points. Start by locating mypy's TypeVar handling and existing diagnostics for generic functions and classes, then inspect tests covering TypeVar usage. Done means a warning or error is emitted for the specified single-use cases without incorrectly flagging valid generic annotations.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100