Function rejects tuple argument when argument type context is a union involving a tuple-bound typevar

[bzoracler]

Bug Report, To Reproduce, and Actual Behaviour

Mypy rejects this example (see the line containing reveal_type(f(b)))

# mypy: disable-error-code=empty-body

type VarTuple[T] = tuple[T, ...]

class MyTuple(tuple[int, str]): ...

def f[T: str | MyTuple](arg: T | VarTuple[T], /) -> T: ...
def f2[T: MyTuple](arg: T | VarTuple[T], /) -> T: ...

b = MyTuple((1, ""))
reveal_type(f(b))  # E: Argument 1 to "f" has incompatible type "MyTuple"; expected "tuple[Never, ...]"  [arg-type] \
                   # N: Revealed type is "Never"
reveal_type(f2(b))  # N: Revealed type is "tuple[int, str, fallback=__main__.MyTuple]"

Expected Behavior

No errors and revealed type for f(b) should be same as for f2(b).

Your Environment

• Mypy version used: 2.1.0 and master (see mypy playground)