Similar issue:

..\Objects\funcobject.c(636): warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data [C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Objects\funcobject.c(637): warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data [C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Objects\funcobject.c(637): warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data [C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\pythoncore.vcxproj]

Extract of function_call() function:

    result = PyEval_EvalCodeEx(
        PyFunction_GET_CODE(func),
        PyFunction_GET_GLOBALS(func), (PyObject *)NULL,
        &PyTuple_GET_ITEM(arg, 0), PyTuple_GET_SIZE(arg),
        k, nk, d, nd,
        PyFunction_GET_KW_DEFAULTS(func),
        PyFunction_GET_CLOSURE(func));

argcount, kwcount and defcount are int, whereas function_call() pass Py_ssize_t values.

function_call() should check PyTuple_GET_SIZE(arg) <= INT_MAX, nk <= INT_MAX and nd <= INT_MAX.