Feature request: Allow unpacking of type variable bound to typed dict

@erictraut

I'd like to have a family of classes where overrides have additional parameters to various methods:

from typing import Generic, Unpack

from typing_extensions import TypedDict, TypeVar, override


class EmptyDict(TypedDict, total=True):
    pass


Extra = TypeVar('Extra', bound=TypedDict, default=EmptyDict)


class C(Generic[Extra]):
    def f(self, **kwargs: Unpack[Extra]) -> None:  # error: Expected TypedDict type argument for Unpack (reportGeneralTypeIssues)
        pass


class D(C):
    @override
    def f(self) -> None:  # error: Method "f" overrides class "C" in an incompatible manner
        pass


class HasName(TypedDict, total=True):
    name: str


class E(C[HasName]):
    @override
    def f(self, name: str) -> None:  # This doesn't work.
        print(name)



D().f()
E().f("a")

See @erictraut's instructive comment on the issue here.

This would be kwargs equivalent of being able to unpack TypeVarTuple. This would I think solve this request to be able to use Paramspec kwargs only.

I have a couple small use cases where this would be nice although they mostly follow other issue of more flexibility with preserving just args/kwargs/similar manipulation.

I believe I hit this issue when I was trying to write a type stub for networkx (or nx).

nx.Graph and its variants allow arbitrary attributes to be associated with nodes, edges, and graphs. For example, adding a node has signature (ref):

class Graph:
    def add_node(self, node_for_adding, **attr): ...

I was trying to do this:

N = TypeVar("N")  # type for node ID
A = TypeVar("A", bound=TypedDict)  # type for node attribute

class Graph(Generic[N, A]):
    def add_node(self, node_for_adding: N, **attr: Unpack[A]) -> None: ...

Yup, perfect example.

Is there something I could help with to speed this up? Probably only possible way to halp is to draft a PEP?

Anyway, it would be really useful for a framework I'm building - https://github.com/paveldedik/ludic/blob/main/ludic/base.py#L293-L308

It seems I can already bound a subclass of a TypedDict in TypeVar and it works in mypy at least:

from typing import TypedDict, TypeVar

class Attrs(TypedDict):
    key: str

T = TypeVar("T", bound=Attrs)  # does not complain

This seems to work in mypy but I'm afraid there is not PEP for it.

T = TypeVar("T", bound=Attrs)  # does not complain

The trouble is Unpack[T] does not accept a TypeVar in place of a concrete TypedDict, regardless of being bounded by a TypedDict

I would also very much like to see this. I stumbled across this limitation when trying to implement a generic class with a typevar that specifies the kwargs a given method can accept.

I need this feature too.

I am making a generic class that stores configuration data for my application. Also it takes some metadata as **kwargs in __init__ method. I want to add typing to it using Generic and TypedDict.

TV = TypeVar("TV")


class MyClass(Generic[TV]):
    init_kwargs: TV

    def __init__(self, **kwargs: Unpack[TV]) -> None:
        self.init_kwargs = kwargs

Usage example:

class MyTD(TypedDict, total=False):
    arg1: int
    arg2: str


a: MyClass[MyTD] = MyClass(arg1=4, arg2="foo")
b: MyClass[MyTD] = MyClass(arg1="bar", arg2=6)  # Should be type error here
reveal_type(a.init_kwargs['arg1'])  # Should be int
reveal_type(a.init_kwargs['arg2'])  # Should be str

But type checker (mypy) throws error:

    def __init__(self, **kwargs: Unpack[TV]) -> None:
#                                       ^^
#                                       Unpack item in ** argument must be a TypedDict

Related: #1395

I need it too

class Example[KW: type[TypedDict]]:
    def __init__(self, **kwargs: Unpack[KW]) -> None:
        ...


class ExampleKwargs(TypedDict):
    foo: int
    bar: str


example: Example[ExampleKwargs] = Example(
    foo=123,  # <- OK
    bar=456  # <- Expected type 'str', got 'int' instead
)

I need it too, I need Unpack can take a TypeVar which bond to TypeDict.

I need it too

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Feature request: Allow unpacking of type variable bound to typed dict #1399

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Feature request: Allow unpacking of type variable bound to typed dict #1399

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hmc-cs-mdrissi commented on May 3, 2023

jaywonchung commented on Sep 8, 2023

NeilGirdhar commented on Sep 9, 2023

paveldedik commented on May 6, 2024

sennalen commented on Jan 7, 2025

mharding-hpe commented on May 3, 2025

t1m013y commented on Jun 29, 2025

RBerga06 commented on Dec 8, 2025

frezX commented on Jan 10, 2026

faithleysath commented on Jan 11, 2026

andrewsonin commented on Apr 11, 2026

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