Enum .name property has str type
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bug
topic-enum
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
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Description
Bug Report
I stumbled across a weird issue with literals and using the .name property with enums. I was wondering if this is expected behavior. Seems inconsistent to me.
To Reproduce
from enum import Enum
from typing import Literal
class Foo(Enum):
A = 1
B = 1
keys = Literal["A", "B", "C"]
def f(name: keys) -> None:
print(name)
foo: Foo = Foo.A
f(foo.name) # Error: Argument 1 to "f" has incompatible type "str"; expected "Literal['A', 'B', 'C']"
f(Foo.A.name) # No Error
Expected Behavior
I would expect both versions to be valid.
Your Environment
- Mypy version used: mypy 1.15.0 (compiled: yes)
- Mypy command-line flags: none
- Mypy configuration options from
mypy.ini(and other config files): none - Python version used: 3.11.11
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 issue's minimal Python 3.11 reproducer with mypy 1.15.0 and compare the inferred types of foo.name and Foo.A.name. Trace the enum and Literal handling involved in those expressions, then add coverage for the reported calls and verify that the behavior matches the agreed expectation.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 45/100