diff -Naur blender-2.83.5.old/source/blender/python/mathutils/mathutils_Matrix.c blender-2.83.5/source/blender/python/mathutils/mathutils_Matrix.c
--- blender-2.83.5.old/source/blender/python/mathutils/mathutils_Matrix.c	2020-08-20 16:59:43.253094831 +0200
+++ blender-2.83.5/source/blender/python/mathutils/mathutils_Matrix.c	2020-08-20 20:46:01.903876602 +0200
@@ -42,7 +42,8 @@
 static PyObject *Matrix_copy(MatrixObject *self);
 static PyObject *Matrix_deepcopy(MatrixObject *self, PyObject *args);
 static int Matrix_ass_slice(MatrixObject *self, int begin, int end, PyObject *value);
-static PyObject *matrix__apply_to_copy(PyNoArgsFunction matrix_func, MatrixObject *self);
+static PyObject *matrix__apply_to_copy(PyObject *(*matrix_func)(MatrixObject *),
+                                       MatrixObject *self);
 static PyObject *MatrixAccess_CreatePyObject(MatrixObject *matrix, const eMatrixAccess_t type);
 
 static int matrix_row_vector_check(MatrixObject *mat, VectorObject *vec, int row)
@@ -395,14 +396,15 @@
   return NULL;
 }
 
-static PyObject *matrix__apply_to_copy(PyNoArgsFunction matrix_func, MatrixObject *self)
+static PyObject *matrix__apply_to_copy(PyObject *(*matrix_func)(MatrixObject *),
+                                       MatrixObject *self)
 {
   PyObject *ret = Matrix_copy(self);
   if (ret) {
-    PyObject *ret_dummy = matrix_func(ret);
+    PyObject *ret_dummy = matrix_func((MatrixObject *)ret);
     if (ret_dummy) {
       Py_DECREF(ret_dummy);
-      return (PyObject *)ret;
+      return ret;
     }
     else { /* error */
       Py_DECREF(ret);
@@ -1737,7 +1739,7 @@
     "   .. note:: When the matrix cant be adjugated a :exc:`ValueError` exception is raised.\n");
 static PyObject *Matrix_adjugated(MatrixObject *self)
 {
-  return matrix__apply_to_copy((PyNoArgsFunction)Matrix_adjugate, self);
+  return matrix__apply_to_copy(Matrix_adjugate, self);
 }
 
 PyDoc_STRVAR(
@@ -1945,7 +1947,7 @@
              "   :rtype: :class:`Matrix`\n");
 static PyObject *Matrix_transposed(MatrixObject *self)
 {
-  return matrix__apply_to_copy((PyNoArgsFunction)Matrix_transpose, self);
+  return matrix__apply_to_copy(Matrix_transpose, self);
 }
 
 /*---------------------------matrix.normalize() ------------------*/
@@ -1991,7 +1993,7 @@
              "   :rtype: :class:`Matrix`\n");
 static PyObject *Matrix_normalized(MatrixObject *self)
 {
-  return matrix__apply_to_copy((PyNoArgsFunction)Matrix_normalize, self);
+  return matrix__apply_to_copy(Matrix_normalize, self);
 }
 
 /*---------------------------matrix.zero() -----------------------*/
diff -Naur blender-2.83.5.old/source/blender/python/mathutils/mathutils_Quaternion.c blender-2.83.5/source/blender/python/mathutils/mathutils_Quaternion.c
--- blender-2.83.5.old/source/blender/python/mathutils/mathutils_Quaternion.c	2020-08-20 16:59:43.253094831 +0200
+++ blender-2.83.5/source/blender/python/mathutils/mathutils_Quaternion.c	2020-08-20 20:47:51.201624646 +0200
@@ -34,7 +34,8 @@
 
 #define QUAT_SIZE 4
 
-static PyObject *quat__apply_to_copy(PyNoArgsFunction quat_func, QuaternionObject *self);
+static PyObject *quat__apply_to_copy(PyObject *(*quat_func)(QuaternionObject *),
+                                     QuaternionObject *self);
 static void quat__axis_angle_sanitize(float axis[3], float *angle);
 static PyObject *Quaternion_copy(QuaternionObject *self);
 static PyObject *Quaternion_deepcopy(QuaternionObject *self, PyObject *args);
@@ -463,7 +464,7 @@
              "   :rtype: :class:`Quaternion`\n");
 static PyObject *Quaternion_normalized(QuaternionObject *self)
 {
-  return quat__apply_to_copy((PyNoArgsFunction)Quaternion_normalize, self);
+  return quat__apply_to_copy(Quaternion_normalize, self);
 }
 
 PyDoc_STRVAR(Quaternion_invert_doc,
@@ -490,7 +491,7 @@
              "   :rtype: :class:`Quaternion`\n");
 static PyObject *Quaternion_inverted(QuaternionObject *self)
 {
-  return quat__apply_to_copy((PyNoArgsFunction)Quaternion_invert, self);
+  return quat__apply_to_copy(Quaternion_invert, self);
 }
 
 PyDoc_STRVAR(Quaternion_identity_doc,
@@ -553,7 +554,7 @@
              "   :rtype: :class:`Quaternion`\n");
 static PyObject *Quaternion_conjugated(QuaternionObject *self)
 {
-  return quat__apply_to_copy((PyNoArgsFunction)Quaternion_conjugate, self);
+  return quat__apply_to_copy(Quaternion_conjugate, self);
 }
 
 PyDoc_STRVAR(Quaternion_copy_doc,
@@ -1385,10 +1386,11 @@
   return Quaternion_CreatePyObject(quat, type);
 }
 
-static PyObject *quat__apply_to_copy(PyNoArgsFunction quat_func, QuaternionObject *self)
+static PyObject *quat__apply_to_copy(PyObject *(*quat_func)(QuaternionObject *),
+                                     QuaternionObject *self)
 {
   PyObject *ret = Quaternion_copy(self);
-  PyObject *ret_dummy = quat_func(ret);
+  PyObject *ret_dummy = quat_func((QuaternionObject *)ret);
   if (ret_dummy) {
     Py_DECREF(ret_dummy);
     return ret;
diff -Naur blender-2.83.5.old/source/blender/python/mathutils/mathutils_Vector.c blender-2.83.5/source/blender/python/mathutils/mathutils_Vector.c
--- blender-2.83.5.old/source/blender/python/mathutils/mathutils_Vector.c	2020-08-20 16:59:43.253094831 +0200
+++ blender-2.83.5/source/blender/python/mathutils/mathutils_Vector.c	2020-08-20 20:48:51.530589513 +0200
@@ -96,10 +96,10 @@
   return Vector_CreatePyObject_alloc(vec, size, type);
 }
 
-static PyObject *vec__apply_to_copy(PyNoArgsFunction vec_func, VectorObject *self)
+static PyObject *vec__apply_to_copy(PyObject *(*vec_func)(VectorObject *), VectorObject *self)
 {
   PyObject *ret = Vector_copy(self);
-  PyObject *ret_dummy = vec_func(ret);
+  PyObject *ret_dummy = vec_func((VectorObject *)ret);
   if (ret_dummy) {
     Py_DECREF(ret_dummy);
     return (PyObject *)ret;
@@ -376,7 +376,7 @@
              "   :rtype: :class:`Vector`\n");
 static PyObject *Vector_normalized(VectorObject *self)
 {
-  return vec__apply_to_copy((PyNoArgsFunction)Vector_normalize, self);
+  return vec__apply_to_copy(Vector_normalize, self);
 }
 
 PyDoc_STRVAR(Vector_resize_doc,