TypyingError when combining variadic and optional arguments

[ricardoV94]

import numba

@numba.njit
def foo(x, y, z=1):
    return x + y + z

assert foo(1, 1) == 3

@numba.njit
def bar(*xy, z=1):
    x, y = xy
    return x + y + z

assert bar(1, 1) == 3  # Raises TypingError: failed to unpack int64

At some point in the inference it iterates over the xy tuple, thinking it is iterating over (xy, z) function arguments

[esc]

I can confirm:

esc@artemis [numba_3.13] (git)-[main] ~/git/numba-issues python numba/10258/10258.py
Traceback (most recent call last):
  File "/Users/esc/git/numba-issues/numba/10258/10258.py", line 14, in <module>
    assert bar(1, 1) == 3  # Raises TypingError: failed to unpack int64
           ~~~^^^^^^
  File "/Users/esc/git/numba/numba/core/dispatcher.py", line 424, in _compile_for_args
    error_rewrite(e, 'typing')
    ~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/esc/git/numba/numba/core/dispatcher.py", line 365, in error_rewrite
    raise e.with_traceback(None)
numba.core.errors.TypingError: Failed in nopython mode pipeline (step: nopython frontend)
failed to unpack int64

File "numba/10258/10258.py", line 11:
def bar(*xy, z=1):
    x, y = xy
    ^

During: typing of exhaust iter at /Users/esc/git/numba-issues/numba/10258/10258.py (11)

File "numba/10258/10258.py", line 11:
def bar(*xy, z=1):
    x, y = xy
    ^

During: Pass nopython_type_inference

[kaeun97]

Let me take a look at this