bpo-41974: Remove complex.__float__, complex.__floordiv__, etc (GH-22593)

Remove complex special methods __int__, __float__, __floordiv__,
__mod__, __divmod__, __rfloordiv__, __rmod__ and __rdivmod__
which always raised a TypeError.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index c30fb4e..2ab3371 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -747,10 +747,10 @@
 int
 PyNumber_Check(PyObject *o)
 {
-    return o && Py_TYPE(o)->tp_as_number &&
-           (Py_TYPE(o)->tp_as_number->nb_index ||
-            Py_TYPE(o)->tp_as_number->nb_int ||
-            Py_TYPE(o)->tp_as_number->nb_float);
+    if (o == NULL)
+        return 0;
+    PyNumberMethods *nb = Py_TYPE(o)->tp_as_number;
+    return nb && (nb->nb_index || nb->nb_int || nb->nb_float || PyComplex_Check(o));
 }
 
 /* Binary operators */
@@ -1461,7 +1461,7 @@
     }
 
     return type_error("int() argument must be a string, a bytes-like object "
-                      "or a number, not '%.200s'", o);
+                      "or a real number, not '%.200s'", o);
 }
 
 PyObject *
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 836a736..990730c 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -522,7 +522,7 @@
     PyErr_Format(PyExc_TypeError,
         "%%%c format: %s is required, not %.200s", type,
         (type == 'o' || type == 'x' || type == 'X') ? "an integer"
-                                                    : "a number",
+                                                    : "a real number",
         Py_TYPE(v)->tp_name);
     return NULL;
 }
diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index 69f6c17..5ab839a 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -510,23 +510,6 @@
 }
 
 static PyObject *
-complex_remainder(PyObject *v, PyObject *w)
-{
-    PyErr_SetString(PyExc_TypeError,
-                    "can't mod complex numbers.");
-    return NULL;
-}
-
-
-static PyObject *
-complex_divmod(PyObject *v, PyObject *w)
-{
-    PyErr_SetString(PyExc_TypeError,
-                    "can't take floor or mod of complex number.");
-    return NULL;
-}
-
-static PyObject *
 complex_pow(PyObject *v, PyObject *w, PyObject *z)
 {
     Py_complex p;
@@ -563,14 +546,6 @@
 }
 
 static PyObject *
-complex_int_div(PyObject *v, PyObject *w)
-{
-    PyErr_SetString(PyExc_TypeError,
-                    "can't take floor of complex number.");
-    return NULL;
-}
-
-static PyObject *
 complex_neg(PyComplexObject *v)
 {
     Py_complex neg;
@@ -668,22 +643,6 @@
     Py_RETURN_NOTIMPLEMENTED;
 }
 
-static PyObject *
-complex_int(PyObject *v)
-{
-    PyErr_SetString(PyExc_TypeError,
-               "can't convert complex to int");
-    return NULL;
-}
-
-static PyObject *
-complex_float(PyObject *v)
-{
-    PyErr_SetString(PyExc_TypeError,
-               "can't convert complex to float");
-    return NULL;
-}
-
 /*[clinic input]
 complex.conjugate
 
@@ -966,7 +925,9 @@
     }
 
     nbr = Py_TYPE(r)->tp_as_number;
-    if (nbr == NULL || (nbr->nb_float == NULL && nbr->nb_index == NULL)) {
+    if (nbr == NULL ||
+        (nbr->nb_float == NULL && nbr->nb_index == NULL && !PyComplex_Check(r)))
+    {
         PyErr_Format(PyExc_TypeError,
                      "complex() first argument must be a string or a number, "
                      "not '%.200s'",
@@ -978,7 +939,9 @@
     }
     if (i != NULL) {
         nbi = Py_TYPE(i)->tp_as_number;
-        if (nbi == NULL || (nbi->nb_float == NULL && nbi->nb_index == NULL)) {
+        if (nbi == NULL ||
+            (nbi->nb_float == NULL && nbi->nb_index == NULL && !PyComplex_Check(i)))
+        {
             PyErr_Format(PyExc_TypeError,
                          "complex() second argument must be a number, "
                          "not '%.200s'",
@@ -1057,8 +1020,8 @@
     (binaryfunc)complex_add,                    /* nb_add */
     (binaryfunc)complex_sub,                    /* nb_subtract */
     (binaryfunc)complex_mul,                    /* nb_multiply */
-    (binaryfunc)complex_remainder,              /* nb_remainder */
-    (binaryfunc)complex_divmod,                 /* nb_divmod */
+    0,                                          /* nb_remainder */
+    0,                                          /* nb_divmod */
     (ternaryfunc)complex_pow,                   /* nb_power */
     (unaryfunc)complex_neg,                     /* nb_negative */
     (unaryfunc)complex_pos,                     /* nb_positive */
@@ -1070,9 +1033,9 @@
     0,                                          /* nb_and */
     0,                                          /* nb_xor */
     0,                                          /* nb_or */
-    complex_int,                                /* nb_int */
+    0,                                          /* nb_int */
     0,                                          /* nb_reserved */
-    complex_float,                              /* nb_float */
+    0,                                          /* nb_float */
     0,                                          /* nb_inplace_add */
     0,                                          /* nb_inplace_subtract */
     0,                                          /* nb_inplace_multiply*/
@@ -1083,7 +1046,7 @@
     0,                                          /* nb_inplace_and */
     0,                                          /* nb_inplace_xor */
     0,                                          /* nb_inplace_or */
-    (binaryfunc)complex_int_div,                /* nb_floor_divide */
+    0,                                          /* nb_floor_divide */
     (binaryfunc)complex_div,                    /* nb_true_divide */
     0,                                          /* nb_inplace_floor_divide */
     0,                                          /* nb_inplace_true_divide */
diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index d0af0ea..828bde1 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -215,7 +215,7 @@
     }
     else {
         PyErr_Format(PyExc_TypeError,
-            "float() argument must be a string or a number, not '%.200s'",
+            "float() argument must be a string or a real number, not '%.200s'",
             Py_TYPE(v)->tp_name);
         return NULL;
     }
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 6ae06a5..01e5c72 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -14839,7 +14839,7 @@
             break;
         default:
             PyErr_Format(PyExc_TypeError,
-                    "%%%c format: a number is required, "
+                    "%%%c format: a real number is required, "
                     "not %.200s",
                     type, Py_TYPE(v)->tp_name);
             break;