bpo-23867: Argument Clinic: inline parsing code for a single positional parameter. (GH-9689)

diff --git a/Modules/clinic/mathmodule.c.h b/Modules/clinic/mathmodule.c.h
index c8d8029..e436f59 100644
--- a/Modules/clinic/mathmodule.c.h
+++ b/Modules/clinic/mathmodule.c.h
@@ -108,7 +108,8 @@
     PyObject *return_value = NULL;
     double x;
 
-    if (!PyArg_Parse(arg, "d:frexp", &x)) {
+    x = PyFloat_AsDouble(arg);
+    if (PyErr_Occurred()) {
         goto exit;
     }
     return_value = math_frexp_impl(module, x);
@@ -168,7 +169,8 @@
     PyObject *return_value = NULL;
     double x;
 
-    if (!PyArg_Parse(arg, "d:modf", &x)) {
+    x = PyFloat_AsDouble(arg);
+    if (PyErr_Occurred()) {
         goto exit;
     }
     return_value = math_modf_impl(module, x);
@@ -352,7 +354,8 @@
     PyObject *return_value = NULL;
     double x;
 
-    if (!PyArg_Parse(arg, "d:degrees", &x)) {
+    x = PyFloat_AsDouble(arg);
+    if (PyErr_Occurred()) {
         goto exit;
     }
     return_value = math_degrees_impl(module, x);
@@ -379,7 +382,8 @@
     PyObject *return_value = NULL;
     double x;
 
-    if (!PyArg_Parse(arg, "d:radians", &x)) {
+    x = PyFloat_AsDouble(arg);
+    if (PyErr_Occurred()) {
         goto exit;
     }
     return_value = math_radians_impl(module, x);
@@ -406,7 +410,8 @@
     PyObject *return_value = NULL;
     double x;
 
-    if (!PyArg_Parse(arg, "d:isfinite", &x)) {
+    x = PyFloat_AsDouble(arg);
+    if (PyErr_Occurred()) {
         goto exit;
     }
     return_value = math_isfinite_impl(module, x);
@@ -433,7 +438,8 @@
     PyObject *return_value = NULL;
     double x;
 
-    if (!PyArg_Parse(arg, "d:isnan", &x)) {
+    x = PyFloat_AsDouble(arg);
+    if (PyErr_Occurred()) {
         goto exit;
     }
     return_value = math_isnan_impl(module, x);
@@ -460,7 +466,8 @@
     PyObject *return_value = NULL;
     double x;
 
-    if (!PyArg_Parse(arg, "d:isinf", &x)) {
+    x = PyFloat_AsDouble(arg);
+    if (PyErr_Occurred()) {
         goto exit;
     }
     return_value = math_isinf_impl(module, x);
@@ -523,4 +530,4 @@
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=8b1709a71e5fb855 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=da4b9940a5cb0188 input=a9049054013a1b77]*/