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mypy assigns dict[Never, Never] to TypeVar bound by dict[str, object] #19895
Description
https://mypy-play.net/?mypy=1.18.2&python=3.12&gist=2e756ebb6f05cb8ef01bcc4cb504c147
def get[D: dict[str, object]](arg: D, /) -> D:
return arg
reveal_type(get({})) # N: Revealed type is "builtins.dict[Never, Never]"This is incorrect, since dict[Never, Never] is not a subtype of dict[str, object]. The solution should have key type str (or Any), but not Never.
See Also: #19641, but this was closed since the caching part of the problem was addressed
Activity
[-]mypy assigns `dict[Never, Never]` to `TypeVar` bound by `Mapping[str, object]`[/-][+]mypy assigns `dict[Never, Never]` to `TypeVar` bound by `dict[str, object]`[/+]ilevkivskyi commentedon Sep 21, 2025
This is intentional (as with other inline empty collection literals).
More precise return types for `TypedDict.get` (#19897)