Tuple unpacking loses length and order information #10723
Description
Describe the bug
Unpacking a tuple and packing to another tuple seem to mess up the typing. It is losing the tuple length information, and seems to mess up the order, too: or why is *i, 2 (2 at the end) inferred as tuple[Literal[2], *tuple[int, ...]] (2 at the front)?
Code or Screenshots
my_dict: dict[tuple[int, int], int] = {}
def foo(i: tuple[int]) -> None:
my_dict[*i, 2] = 3
foo((1,))
assert my_dict == {(1, 2): 3}gives
bug.py
bug.py:4:5 - error: Argument of type "tuple[Literal[2], *tuple[int, ...]]" cannot be assigned to parameter "key" of type "tuple[int, int]" in function "__setitem__"
"tuple[Literal[2], *tuple[int, ...]]" is not assignable to "tuple[int, int]"
Tuple size mismatch; expected 2 but received indeterminate (reportArgumentType)
1 error, 0 warnings, 0 informations
VS Code extension or command-line
Python pyright v1.1.403