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Description
Bug Report
If Literals are given as Unions they aren't accepted as TypedDict Keys
To Reproduce
from typing import TypedDict, reveal_type, Final, Literal, TypeAlias, get_args
from datetime import datetime
class RangeInfo(TypedDict):
begin: datetime
end: datetime
created_start: datetime
created_end: datetime
# …
TimeRange: TypeAlias = Literal["begin", "end"]
CreatedRange: TypeAlias = Literal["created_start", "created_end"]
RANGES: Final[tuple[tuple[TimeRange | CreatedRange, ...],... ]] = (
get_args(TimeRange),
get_args(CreatedRange),
# … much more range names
)
def check_ranges(option: RangeInfo) -> None:
"""Ensure given datetime ranges are valid"""
for range_tuple in RANGES:
reveal_type(range_tuple) # builtins.tuple[Union[Union[Literal['begin'], Literal['end']], Union[Literal['created_start'], Literal['created_end']]], ...]
for range_val in range_tuple:
reveal_type(range_val) # Union[Union[Literal['begin'], Literal['end']], Union[Literal['created_start'], Literal['created_end']]]
if not isinstance(option[range_val], datetime): # ❌ TypedDict key must be a string literal; expected one of ("begin", "end", "created_start", "created_end") [literal-required]
raise ValueError(f"{range_val} is not a datetime")
# … much more checks
def minimal_okay(union: Literal["begin"] | Literal["end"], option: RangeInfo) -> datetime:
return option[union]
def minimal_fail(union: TimeRange | CreatedRange, option: RangeInfo) -> datetime:
return option[union] # ❌ TypedDict key must be a string literal; expected one of ("begin", "end", "created_start", "created_end") [literal-required]Expected Behavior
There should be no type error, Literals in Unions should be flattened.
I would love if unions of literals are flattened in general.
Literal["a"] | Literal["b"] | (Literal["c"] | Literal["d"]) == Literal["a", "b", "c", "d"]
But I guess this is yet another issue.
Actual Behavior
Can't access typed dict without type error
Your Environment
(see mypy play)
Related #16813