Constrained TypeVar default causes false positive error if the default is a TypedDict type #17686

Bug Report, To Reproduce, & Expected Behaviour

An error occurs when defining a constrained type variable where the default is a TypedDict type. See mypy Playground:

import typing as t

class A(t.TypedDict):
    a: int

T = t.TypeVar("T", int, A, default=A)  # E: TypeVar default must be one of the constraint types  [misc]

class C(t.Generic[T]): ...

# Using the type variable still correctly gets its default
reveal_type(C())  # OK: C[TypedDict("A", {"a": int})]

Expected Behavior

No errors

Your Environment

• Mypy version used: 1.10.1, 1.11.1
• Mypy command-line flags: None
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.10, 3.12