TypedDict doesn't support Union[Literal] as key "string literal"
Open
Nobody has claimed this yet.
bug
priority-2-low
topic-literal-types
topic-typed-dict
topic-union-types
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
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Description
Possibly bug.
Related: https://github.com/python/mypy/issues/7644
Reproducible example
from typing_extensions import Literal, TypedDict
class TDict(TypedDict):
KEY1: int
KEY2: int
d1: TDict = {'KEY1': 1, 'KEY2': 2}
key2: Literal['KEY1']
d2: TDict = {key2: 1, 'KEY2': 2}
key3: Literal['KEY1', 'KEY2']
d3: TDict = {key3: 1, 'KEY2': 2} # error: Expected TypedDict key to be string literal
I use mypy 0.740 and python3.6
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 provided TypedDict and Literal examples with mypy 0.740, focusing on the d3 assignment that reports “Expected TypedDict key to be string literal.” Done means the reproducible union-of-literals key case is accepted consistently with the single-literal case.
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