python / python/mypy

"Trying to read deleted variable" false negative when deleted variable used on its own

Open
#13,225 0 comments 1 reaction 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

a = 1
del a

a # no error

print(a) # error

playground

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

Start with the linked mypy playground and reproduce the difference between using the deleted variable as a standalone expression and passing it to print(). Trace how each use is analyzed and make the standalone use report the same deleted-variable error, then add coverage for the example.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
compilers
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.