`TypedDict.copy()` falls back to `dict[str, object]`

from __future__ import annotations

from typing_extensions import TypedDict, assert_type, reveal_type


class A(TypedDict, closed=True):
    a: int


class B(TypedDict, closed=True):
    b: str


a = A(a=1)
b = B(b="b")

a_copy = a.copy()
b_copy = b.copy()

assert_type(a, A)
assert_type(b, B)


def copy_bound[T: A | B](obj: T) -> T:
    result = obj.copy()  # ty: ignore[invalid-argument-type]
    reveal_type(result)
    # pyright   'Type of "result" is "A* | B*"'
    # ty        'Revealed type:      `Unknown`'
    # pyrefly   'revealed type:      dict[str, object]'
    return result

def copy_constrained[T: (A, B)](obj: T) -> T:
    result = obj.copy()
    reveal_type(result)
    # pyright   'Type of "result" is  "A* | B*"'
    # ty        'Revealed type:       `T@copy_constrained`'
    # pyrefly   'revealed type:       dict[str, object] & T'
    return result