diff --git a/Objects/cellobject.c b/Objects/cellobject.c
index b1154e4ca4a..590c8a80857 100644
--- a/Objects/cellobject.c
+++ b/Objects/cellobject.c
@@ -5,6 +5,8 @@
 #include "pycore_modsupport.h"    // _PyArg_NoKeywords()
 #include "pycore_object.h"
 
+#define _PyCell_CAST(op) _Py_CAST(PyCellObject*, (op))
+
 PyObject *
 PyCell_New(PyObject *obj)
 {
@@ -72,8 +74,9 @@ PyCell_Set(PyObject *op, PyObject *value)
 }
 
 static void
-cell_dealloc(PyCellObject *op)
+cell_dealloc(PyObject *self)
 {
+    PyCellObject *op = _PyCell_CAST(self);
     _PyObject_GC_UNTRACK(op);
     Py_XDECREF(op->ob_ref);
     PyObject_GC_Del(op);
@@ -100,10 +103,12 @@ cell_richcompare(PyObject *a, PyObject *b, int op)
 }
 
 static PyObject *
-cell_repr(PyCellObject *op)
+cell_repr(PyObject *self)
 {
-    if (op->ob_ref == NULL)
+    PyCellObject *op = _PyCell_CAST(self);
+    if (op->ob_ref == NULL) {
         return PyUnicode_FromFormat("<cell at %p: empty>", op);
+    }
 
     return PyUnicode_FromFormat("<cell at %p: %.80s object at %p>",
                                op, Py_TYPE(op->ob_ref)->tp_name,
@@ -111,24 +116,26 @@ cell_repr(PyCellObject *op)
 }
 
 static int
-cell_traverse(PyCellObject *op, visitproc visit, void *arg)
+cell_traverse(PyObject *self, visitproc visit, void *arg)
 {
+    PyCellObject *op = _PyCell_CAST(self);
     Py_VISIT(op->ob_ref);
     return 0;
 }
 
 static int
-cell_clear(PyCellObject *op)
+cell_clear(PyObject *self)
 {
+    PyCellObject *op = _PyCell_CAST(self);
     Py_CLEAR(op->ob_ref);
     return 0;
 }
 
 static PyObject *
-cell_get_contents(PyCellObject *op, void *closure)
+cell_get_contents(PyObject *self, void *closure)
 {
-    if (op->ob_ref == NULL)
-    {
+    PyCellObject *op = _PyCell_CAST(self);
+    if (op->ob_ref == NULL) {
         PyErr_SetString(PyExc_ValueError, "Cell is empty");
         return NULL;
     }
@@ -136,15 +143,15 @@ cell_get_contents(PyCellObject *op, void *closure)
 }
 
 static int
-cell_set_contents(PyCellObject *op, PyObject *obj, void *Py_UNUSED(ignored))
+cell_set_contents(PyObject *self, PyObject *obj, void *Py_UNUSED(ignored))
 {
+    PyCellObject *op = _PyCell_CAST(self);
     Py_XSETREF(op->ob_ref, Py_XNewRef(obj));
     return 0;
 }
 
 static PyGetSetDef cell_getsetlist[] = {
-    {"cell_contents", (getter)cell_get_contents,
-                      (setter)cell_set_contents, NULL},
+    {"cell_contents", cell_get_contents, cell_set_contents, NULL},
     {NULL} /* sentinel */
 };
 
@@ -153,12 +160,12 @@ PyTypeObject PyCell_Type = {
     "cell",
     sizeof(PyCellObject),
     0,
-    (destructor)cell_dealloc,                   /* tp_dealloc */
+    cell_dealloc,                               /* tp_dealloc */
     0,                                          /* tp_vectorcall_offset */
     0,                                          /* tp_getattr */
     0,                                          /* tp_setattr */
     0,                                          /* tp_as_async */
-    (reprfunc)cell_repr,                        /* tp_repr */
+    cell_repr,                                  /* tp_repr */
     0,                                          /* tp_as_number */
     0,                                          /* tp_as_sequence */
     0,                                          /* tp_as_mapping */
@@ -170,8 +177,8 @@ PyTypeObject PyCell_Type = {
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,    /* tp_flags */
     cell_new_doc,                               /* tp_doc */
-    (traverseproc)cell_traverse,                /* tp_traverse */
-    (inquiry)cell_clear,                        /* tp_clear */
+    cell_traverse,                              /* tp_traverse */
+    cell_clear,                                 /* tp_clear */
     cell_richcompare,                           /* tp_richcompare */
     0,                                          /* tp_weaklistoffset */
     0,                                          /* tp_iter */
@@ -186,6 +193,6 @@ PyTypeObject PyCell_Type = {
     0,                                          /* tp_dictoffset */
     0,                                          /* tp_init */
     0,                                          /* tp_alloc */
-    (newfunc)cell_new,                          /* tp_new */
+    cell_new,                                   /* tp_new */
     0,                                          /* tp_free */
 };