False positive with assignment expression shadowing a builtin
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Nobody has claimed this yet.
bug
topic-pep-572
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
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Description
To Reproduce
https://mypy-play.net/?mypy=latest&python=3.11&gist=a7fd112a423a2e565e5f2cd3e3607e58
def foo(x: int) -> int:
res = vars + 1 if (vars := x) else 0
return res
Expected Behavior
This should type check without errors. It does if I rename vars to anything that is not a name of a built-in.
Actual Behavior
main.py:2: error: Unsupported operand types for + (overloaded function and "int") [operator]
Your Environment
- Mypy version used: 1.5.1
- Mypy command-line flags: no
- Mypy configuration options from
mypy.ini(and other config files): no - Python version used: 3.11
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 by running the linked mypy-play reproducer with Python 3.11 and mypy 1.5.1, then trace how the assignment expression and the name vars are analyzed. Done means the example type checks without the reported operator error while preserving the existing behavior for builtin names.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100