Previously, the result could have been an instance of a subclass of int.
Also revert bpo-26202 and make attributes start, stop and step of the range
object having exact type int.
Add private function _PyNumber_Index() which preserves the old behavior
of PyNumber_Index() for performance to use it in the conversion functions
like PyLong_AsLong().
All keywords should first be checked for pointer identity. Only
after that failed for all keywords (unlikely) should unicode
equality be used.
The original code would call unicode equality on any non-matching
keyword argument. Meaning calling it often e.g. when a function
has many kwargs but only the last one is provided.
The fact that keyword names are strings is now part of the vectorcall and `METH_FASTCALL` protocols. The biggest concrete change is that `_PyStack_UnpackDict` now checks that and raises `TypeError` if not.
CC @markshannon @vstinner
https://bugs.python.org/issue37540
* _PyTuple_ITEMS() gives access to the tuple->ob_item field and cast the
first argument to PyTupleObject*. This internal macro is only usable if
Py_BUILD_CORE is defined.
* Replace &PyTuple_GET_ITEM(ob, 0) with _PyTuple_ITEMS(ob).
* Replace PyTuple_GET_ITEM(op, 1) with &_PyTuple_ITEMS(ob)[1].
