Use Py_ssize_t in slices

Objects/sliceobject.c

@@ -107,20 +107,20 @@ PySlice_GetIndices(PySliceObject *r, Py_ssize_t length,
 		*step = 1;
 	} else {
 		if (!PyInt_Check(r->step)) return -1;
-		*step = PyInt_AsLong(r->step);
+		*step = PyInt_AsSsize_t(r->step);
 	}
 	if (r->start == Py_None) {
 		*start = *step < 0 ? length-1 : 0;
 	} else {
 		if (!PyInt_Check(r->start)) return -1;
-		*start = PyInt_AsLong(r->start);
+		*start = PyInt_AsSsize_t(r->start);
 		if (*start < 0) *start += length;
 	}
 	if (r->stop == Py_None) {
 		*stop = *step < 0 ? -1 : length;
 	} else {
 		if (!PyInt_Check(r->stop)) return -1;
-		*stop = PyInt_AsLong(r->stop);
+		*stop = PyInt_AsSsize_t(r->stop);
 		if (*stop < 0) *stop += length;
 	}
 	if (*stop > length) return -1;
@@ -252,7 +252,7 @@ slice_indices(PySliceObject* self, PyObject* len)
 {
 	Py_ssize_t ilen, start, stop, step, slicelength;
 
-	ilen = PyInt_AsLong(len);
+	ilen = PyInt_AsSsize_t(len);
 
 	if (ilen == -1 && PyErr_Occurred()) {
 		return NULL;
@@ -263,7 +263,7 @@ slice_indices(PySliceObject* self, PyObject* len)
 		return NULL;
 	}
 
-	return Py_BuildValue("(iii)", start, stop, step);
+	return Py_BuildValue("(nnn)", start, stop, step);
 }
 
 PyDoc_STRVAR(slice_indices_doc,