Ad hoc fix to allow comparison of two unpacked types in overload

Currently, mypy crashes at comparison of two overloads that use
unpacking on unbounded tuple types. This adds an ad hoc fix
by adding the correspond check in the function and instead
compares the two wrapped inner types that are unpacked.

See mypy issue python#17319:
python#17319

Author: felixblanke

mypy/meet.py

@@ -547,6 +547,9 @@ def _type_object_overlap(left: Type, right: Type) -> bool:
     # Note: it's unclear however, whether returning False is the right thing
     # to do when inferring reachability -- see  https://github.com/python/mypy/issues/5529
 
+    if isinstance(left, UnpackType) and isinstance(right, UnpackType):
+        return _is_overlapping_types(left.type, right.type)
+
     assert type(left) != type(right), f"{type(left)} vs {type(right)}"
     return False