Generic TypedDict update() doesn't accept another instance of itself

[TeamSpen210]

Bug Report

A generic TypeDict's update() doesn't allow calls with another similar dict, even though a non-generic version works fine. In my actual use-case I'm using constrained typevars, but the same issue occurs with unconstrained ones.

To Reproduce

from typing import TypedDict, reveal_type

class Group[ValT](TypedDict):
    a: ValT
    
value: Group[int] = {"a": 1}

def func(value2: Group[int]) -> None:
    reveal_type(value) # TypedDict('__main__.Group', {'a': builtins.int})
    reveal_type(value.update) # def (TypedDict('__main__.Group', {'a': builtins.int}))
    reveal_type(value2) # TypedDict('__main__.Group', {'a': builtins.int})
    # error: Argument 1 to "update" of "TypedDict" has incompatible type "Group[int]"; expected "TypedDict({'a': ValT})"  [typeddict-item]
    value.update(value2)

https://mypy-play.net/?mypy=master&python=3.12&gist=2a40a79bdb543d8b28669f40bdc1c876

Expected Behavior

The update() call is accepted without error, the same as the non-generic version.

Actual Behavior

update() doesn't seem to have solved typevars, though reveal_type shows the correct function definition.

Your Environment

• Mypy version used: 1.19.1, also tried master (1.20.0+dev.c5c12fad9e69525fa5b12058b328d284c5feecc4)
• Mypy command-line flags: Playground defaults
• Mypy configuration options from mypy.ini (and other config files): Playground defaults
• Python version used: 3.12, 3.14