python / python/mypy

Calling float.__add__ with an integer as first argument is valid

Open
#17,089 3 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

bug
Dominant language
Python
Stars
20.6k
Forks
3.3k
PR merge metrics
PR metrics pending

Description

Calling float.__add__ with an integer as first argument is valid.

Example

float.__add__(1, 2)

Expected Behavior

Considering that the code fails at runtime, mypy should not accept this code.

Environment

  • Mypy version used: 1.9
  • Python version used: 3.11.2

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.

Research direction

No file or test is named. Start by reproducing the example with mypy 1.9, then trace how direct calls to float.add are checked and find the relevant regression-test area. Done means mypy rejects float.add(1, 2) while preserving valid uses.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
compilers, devtools
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.