Check attributes for variance violations

Open
#735 4 comments 1 reaction 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
compilers

Research direction

Start by comparing this request with issue #734, then trace the existing variance checks for classes and determine where instance attributes are analyzed. Done means covariant classes reject attributes such as List[T] when the attribute type is invariant, with coverage for the reported case.

Written by the indexing model from the issue text.

Description

bug priority-1-normal topic-type-variables

Similar to #734, but for attributes. In a covariant class an instance attribute with type List[T] would not be valid, since List is invariant.

Dominant language
Python
Stars
20.6k
Forks
3.3k
Avg merge
1d 18h
Merged PRs (30d)
54

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from python/mypy

All issues in python/mypy

Similar issues

More Python issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.