bpo-35582: Argument Clinic: inline parsing code for positional parameters. (GH-11313)

diff --git a/Objects/clinic/floatobject.c.h b/Objects/clinic/floatobject.c.h
index 28b24d0..741ca3b 100644
--- a/Objects/clinic/floatobject.c.h
+++ b/Objects/clinic/floatobject.c.h
@@ -229,7 +229,7 @@
     const char *typestr;
 
     if (!PyUnicode_Check(arg)) {
-        _PyArg_BadArgument("__getformat__", "str", arg);
+        _PyArg_BadArgument("__getformat__", 0, "str", arg);
         goto exit;
     }
     Py_ssize_t typestr_length;
@@ -279,8 +279,33 @@
     const char *typestr;
     const char *fmt;
 
-    if (!_PyArg_ParseStack(args, nargs, "ss:__set_format__",
-        &typestr, &fmt)) {
+    if (!_PyArg_CheckPositional("__set_format__", nargs, 2, 2)) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("__set_format__", 1, "str", args[0]);
+        goto exit;
+    }
+    Py_ssize_t typestr_length;
+    typestr = PyUnicode_AsUTF8AndSize(args[0], &typestr_length);
+    if (typestr == NULL) {
+        goto exit;
+    }
+    if (strlen(typestr) != (size_t)typestr_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[1])) {
+        _PyArg_BadArgument("__set_format__", 2, "str", args[1]);
+        goto exit;
+    }
+    Py_ssize_t fmt_length;
+    fmt = PyUnicode_AsUTF8AndSize(args[1], &fmt_length);
+    if (fmt == NULL) {
+        goto exit;
+    }
+    if (strlen(fmt) != (size_t)fmt_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
     return_value = float___set_format___impl(type, typestr, fmt);
@@ -308,7 +333,7 @@
     PyObject *format_spec;
 
     if (!PyUnicode_Check(arg)) {
-        _PyArg_BadArgument("__format__", "str", arg);
+        _PyArg_BadArgument("__format__", 0, "str", arg);
         goto exit;
     }
     if (PyUnicode_READY(arg) == -1) {
@@ -320,4 +345,4 @@
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=e8f8be828462d58b input=a9049054013a1b77]*/
+/*[clinic end generated code: output=2631a60701a8f7d4 input=a9049054013a1b77]*/