bpo-36127: Argument Clinic: inline parsing code for keyword parameters. (GH-12058)

65 files changed, 7461 insertions, 863 deletions

diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
index 4adeded303..31ea0d1458 100644
--- a/Doc/whatsnew/3.8.rst
+++ b/Doc/whatsnew/3.8.rst
@@ -442,6 +442,11 @@ Optimizations
   (Contributed by Stefan Behnel, Pablo Galindo Salgado, Raymond Hettinger,
   Neil Schemenauer, and Serhiy Storchaka in :issue:`36012`.)
 
+* Reduced an overhead of converting arguments passed to many builtin functions
+  and methods.  This sped up calling some simple builtin functions and
+  methods up to 20--50%.  (Contributed by Serhiy Storchaka in :issue:`23867`,
+  :issue:`35582` and :issue:`36127`.)
+
 
 Build and C API Changes
 =======================
diff --git a/Include/modsupport.h b/Include/modsupport.h
index f17060c2e1..66a5ec839e 100644
--- a/Include/modsupport.h
+++ b/Include/modsupport.h
@@ -118,6 +118,18 @@ PyAPI_FUNC(int) _PyArg_ParseStackAndKeywords(
     ...);
 PyAPI_FUNC(int) _PyArg_VaParseTupleAndKeywordsFast(PyObject *, PyObject *,
                                                    struct _PyArg_Parser *, va_list);
+PyAPI_FUNC(PyObject * const *) _PyArg_UnpackKeywords(
+        PyObject *const *args, Py_ssize_t nargs,
+        PyObject *kwargs, PyObject *kwnames,
+        struct _PyArg_Parser *parser,
+        int minpos, int maxpos, int minkw,
+        PyObject **buf);
+#define _PyArg_UnpackKeywords(args, nargs, kwargs, kwnames, parser, minpos, maxpos, minkw, buf) \
+    (((minkw) == 0 && (kwargs) == NULL && (kwnames) == NULL && \
+      (minpos) <= (nargs) && (nargs) <= (maxpos) && args != NULL) ? (args) : \
+     _PyArg_UnpackKeywords((args), (nargs), (kwargs), (kwnames), (parser), \
+                           (minpos), (maxpos), (minkw), (buf)))
+
 void _PyArg_Fini(void);
 #endif   /* Py_LIMITED_API */
 
diff --git a/Lib/test/clinic.test b/Lib/test/clinic.test
index b8f2331b43..62c2f00c6b 100644
--- a/Lib/test/clinic.test
+++ b/Lib/test/clinic.test
@@ -3,6 +3,7 @@ output preset block
 [clinic start generated code]*/
 /*[clinic end generated code: output=da39a3ee5e6b4b0d input=3c81ac2402d06a8b]*/
 
+
 /*[clinic input]
 test_object_converter
 
@@ -59,6 +60,7 @@ test_object_converter_impl(PyObject *module, PyObject *a, PyObject *b,
                            PyObject *c, PyUnicode_Object *d)
 /*[clinic end generated code: output=f2c26174b3d46e94 input=005e6a8a711a869b]*/
 
+
 /*[clinic input]
 test_object_converter_one_arg
 
@@ -79,6 +81,7 @@ static PyObject *
 test_object_converter_one_arg(PyObject *module, PyObject *a)
 /*[clinic end generated code: output=6da755f8502139df input=d635d92a421f1ca3]*/
 
+
 /*[clinic input]
 test_objects_converter
 
@@ -125,6 +128,7 @@ static PyObject *
 test_objects_converter_impl(PyObject *module, PyObject *a, PyObject *b)
 /*[clinic end generated code: output=58009c0e42b4834e input=4cbb3d9edd2a36f3]*/
 
+
 /*[clinic input]
 test_object_converter_subclass_of
 
@@ -238,6 +242,7 @@ test_object_converter_subclass_of_impl(PyObject *module, PyObject *a,
                                        PyObject *h, PyObject *i, PyObject *j)
 /*[clinic end generated code: output=99691bda8eeda6d6 input=31b06b772d5f983e]*/
 
+
 /*[clinic input]
 test_PyBytesObject_converter
 
@@ -278,6 +283,7 @@ static PyObject *
 test_PyBytesObject_converter_impl(PyObject *module, PyBytesObject *a)
 /*[clinic end generated code: output=5d9a301c1df24eb5 input=12b10c7cb5750400]*/
 
+
 /*[clinic input]
 test_PyByteArrayObject_converter
 
@@ -318,6 +324,7 @@ static PyObject *
 test_PyByteArrayObject_converter_impl(PyObject *module, PyByteArrayObject *a)
 /*[clinic end generated code: output=9455d06f4f09637b input=5a657da535d194ae]*/
 
+
 /*[clinic input]
 test_unicode_converter
 
@@ -361,6 +368,7 @@ static PyObject *
 test_unicode_converter_impl(PyObject *module, PyObject *a)
 /*[clinic end generated code: output=9275c04fe204f4c5 input=aa33612df92aa9c5]*/
 
+
 /*[clinic input]
 test_bool_converter
 
@@ -430,6 +438,7 @@ static PyObject *
 test_bool_converter_impl(PyObject *module, int a, int b, int c)
 /*[clinic end generated code: output=25f20963894256a1 input=939854fa9f248c60]*/
 
+
 /*[clinic input]
 test_char_converter
 
@@ -683,6 +692,7 @@ test_char_converter_impl(PyObject *module, char a, char b, char c, char d,
                          char k, char l, char m, char n)
 /*[clinic end generated code: output=e041d687555e0a5d input=e42330417a44feac]*/
 
+
 /*[clinic input]
 test_unsigned_char_converter
 
@@ -799,6 +809,7 @@ test_unsigned_char_converter_impl(PyObject *module, unsigned char a,
                                   unsigned char b, unsigned char c)
 /*[clinic end generated code: output=ebf905c5c9414762 input=021414060993e289]*/
 
+
 /*[clinic input]
 test_short_converter
 
@@ -865,6 +876,7 @@ static PyObject *
 test_short_converter_impl(PyObject *module, short a)
 /*[clinic end generated code: output=86fe1a1496a7ff20 input=6a8a7a509a498ff4]*/
 
+
 /*[clinic input]
 test_unsigned_short_converter
 
@@ -934,6 +946,7 @@ test_unsigned_short_converter_impl(PyObject *module, unsigned short a,
                                    unsigned short b, unsigned short c)
 /*[clinic end generated code: output=3779fe104319e3ae input=cdfd8eff3d9176b4]*/
 
+
 /*[clinic input]
 test_int_converter
 
@@ -1030,6 +1043,7 @@ static PyObject *
 test_int_converter_impl(PyObject *module, int a, int b, int c, myenum d)
 /*[clinic end generated code: output=de74e24e85a669a5 input=d20541fc1ca0553e]*/
 
+
 /*[clinic input]
 test_unsigned_int_converter
 
@@ -1099,6 +1113,7 @@ test_unsigned_int_converter_impl(PyObject *module, unsigned int a,
                                  unsigned int b, unsigned int c)
 /*[clinic end generated code: output=189176ce67c7d2e7 input=5533534828b62fc0]*/
 
+
 /*[clinic input]
 test_long_converter
 
@@ -1150,6 +1165,7 @@ static PyObject *
 test_long_converter_impl(PyObject *module, long a)
 /*[clinic end generated code: output=44cd8823f59d116b input=d2179e3c9cdcde89]*/
 
+
 /*[clinic input]
 test_unsigned_long_converter
 
@@ -1215,6 +1231,7 @@ test_unsigned_long_converter_impl(PyObject *module, unsigned long a,
                                   unsigned long b, unsigned long c)
 /*[clinic end generated code: output=1c05c871c0309e08 input=f450d94cae1ef73b]*/
 
+
 /*[clinic input]
 test_long_long_converter
 
@@ -1266,6 +1283,7 @@ static PyObject *
 test_long_long_converter_impl(PyObject *module, long long a)
 /*[clinic end generated code: output=3e8083f3aee4f18a input=d5fc81577ff4dd02]*/
 
+
 /*[clinic input]
 test_unsigned_long_long_converter
 
@@ -1335,6 +1353,7 @@ test_unsigned_long_long_converter_impl(PyObject *module,
                                        unsigned long long c)
 /*[clinic end generated code: output=0a9b17fb824e28eb input=a15115dc41866ff4]*/
 
+
 /*[clinic input]
 test_Py_ssize_t_converter
 
@@ -1426,6 +1445,7 @@ test_Py_ssize_t_converter_impl(PyObject *module, Py_ssize_t a, Py_ssize_t b,
                                Py_ssize_t c)
 /*[clinic end generated code: output=a46d2aaf40c10398 input=3855f184bb3f299d]*/
 
+
 /*[clinic input]
 test_slice_index_converter
 
@@ -1489,6 +1509,7 @@ test_slice_index_converter_impl(PyObject *module, Py_ssize_t a, Py_ssize_t b,
                                 Py_ssize_t c)
 /*[clinic end generated code: output=2148703cd3c6e941 input=edeadb0ee126f531]*/
 
+
 /*[clinic input]
 test_size_t_converter
 
@@ -1534,6 +1555,7 @@ static PyObject *
 test_size_t_converter_impl(PyObject *module, size_t a)
 /*[clinic end generated code: output=8a91a9ca8a92dabb input=52e93a0fed0f1fb3]*/
 
+
 /*[clinic input]
 test_float_converter
 
@@ -1580,6 +1602,7 @@ static PyObject *
 test_float_converter_impl(PyObject *module, float a)
 /*[clinic end generated code: output=8293566b2ec1fc52 input=259c0d98eca35034]*/
 
+
 /*[clinic input]
 test_double_converter
 
@@ -1626,6 +1649,7 @@ static PyObject *
 test_double_converter_impl(PyObject *module, double a)
 /*[clinic end generated code: output=487081a9b8da67ab input=c6a9945706a41c27]*/
 
+
 /*[clinic input]
 test_Py_complex_converter
 
@@ -1665,6 +1689,7 @@ static PyObject *
 test_Py_complex_converter_impl(PyObject *module, Py_complex a)
 /*[clinic end generated code: output=c2ecbec2144ca540 input=070f216a515beb79]*/
 
+
 /*[clinic input]
 test_str_converter
 
@@ -1730,6 +1755,7 @@ test_str_converter_impl(PyObject *module, const char *a, const char *b,
                         const char *h, Py_ssize_clean_t h_length)
 /*[clinic end generated code: output=8415d82c56154307 input=8afe9da8185cd38c]*/
 
+
 /*[clinic input]
 test_str_converter_encoding
 
@@ -1804,6 +1830,7 @@ test_str_converter_encoding_impl(PyObject *module, char *a, char *b, char *c,
                                  Py_ssize_clean_t e_length)
 /*[clinic end generated code: output=f579dd9e795a364e input=eb4c38e1f898f402]*/
 
+
 /*[clinic input]
 test_Py_UNICODE_converter
 
@@ -1863,6 +1890,7 @@ test_Py_UNICODE_converter_impl(PyObject *module, const Py_UNICODE *a,
                                Py_ssize_clean_t e_length)
 /*[clinic end generated code: output=dd0a09a1b772e57b input=064a3b68ad7f04b0]*/
 
+
 /*[clinic input]
 test_Py_buffer_converter
 
@@ -1932,3 +1960,1238 @@ static PyObject *
 test_Py_buffer_converter_impl(PyObject *module, Py_buffer *a, Py_buffer *b,
                               Py_buffer *c, Py_buffer *d, Py_buffer *e)
 /*[clinic end generated code: output=5760c82faa2ed61f input=6a9da0f56f9525fd]*/
+
+
+/*[clinic input]
+test_keywords
+
+    a: object
+    b: object
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_keywords__doc__,
+"test_keywords($module, /, a, b)\n"
+"--\n"
+"\n");
+
+#define TEST_KEYWORDS_METHODDEF    \
+    {"test_keywords", (PyCFunction)(void(*)(void))test_keywords, METH_FASTCALL|METH_KEYWORDS, test_keywords__doc__},
+
+static PyObject *
+test_keywords_impl(PyObject *module, PyObject *a, PyObject *b);
+
+static PyObject *
+test_keywords(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"a", "b", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_keywords", 0};
+    PyObject *argsbuf[2];
+    PyObject *a;
+    PyObject *b;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    return_value = test_keywords_impl(module, a, b);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_keywords_impl(PyObject *module, PyObject *a, PyObject *b)
+/*[clinic end generated code: output=4be6cf045ea8242e input=0d3484844749c05b]*/
+
+
+/*[clinic input]
+test_keywords_kwonly
+
+    a: object
+    *
+    b: object
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_keywords_kwonly__doc__,
+"test_keywords_kwonly($module, /, a, *, b)\n"
+"--\n"
+"\n");
+
+#define TEST_KEYWORDS_KWONLY_METHODDEF    \
+    {"test_keywords_kwonly", (PyCFunction)(void(*)(void))test_keywords_kwonly, METH_FASTCALL|METH_KEYWORDS, test_keywords_kwonly__doc__},
+
+static PyObject *
+test_keywords_kwonly_impl(PyObject *module, PyObject *a, PyObject *b);
+
+static PyObject *
+test_keywords_kwonly(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"a", "b", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_keywords_kwonly", 0};
+    PyObject *argsbuf[2];
+    PyObject *a;
+    PyObject *b;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 1, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    return_value = test_keywords_kwonly_impl(module, a, b);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_keywords_kwonly_impl(PyObject *module, PyObject *a, PyObject *b)
+/*[clinic end generated code: output=d63c4977a7a80713 input=384adc78bfa0bff7]*/
+
+
+/*[clinic input]
+test_keywords_opt
+
+    a: object
+    b: object = None
+    c: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_keywords_opt__doc__,
+"test_keywords_opt($module, /, a, b=None, c=None)\n"
+"--\n"
+"\n");
+
+#define TEST_KEYWORDS_OPT_METHODDEF    \
+    {"test_keywords_opt", (PyCFunction)(void(*)(void))test_keywords_opt, METH_FASTCALL|METH_KEYWORDS, test_keywords_opt__doc__},
+
+static PyObject *
+test_keywords_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                       PyObject *c);
+
+static PyObject *
+test_keywords_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"a", "b", "c", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_keywords_opt", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        b = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    c = args[2];
+skip_optional_pos:
+    return_value = test_keywords_opt_impl(module, a, b, c);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_keywords_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                       PyObject *c)
+/*[clinic end generated code: output=e5e50d114d8fc10a input=eda7964f784f4607]*/
+
+
+/*[clinic input]
+test_keywords_opt_kwonly
+
+    a: object
+    b: object = None
+    *
+    c: object = None
+    d: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_keywords_opt_kwonly__doc__,
+"test_keywords_opt_kwonly($module, /, a, b=None, *, c=None, d=None)\n"
+"--\n"
+"\n");
+
+#define TEST_KEYWORDS_OPT_KWONLY_METHODDEF    \
+    {"test_keywords_opt_kwonly", (PyCFunction)(void(*)(void))test_keywords_opt_kwonly, METH_FASTCALL|METH_KEYWORDS, test_keywords_opt_kwonly__doc__},
+
+static PyObject *
+test_keywords_opt_kwonly_impl(PyObject *module, PyObject *a, PyObject *b,
+                              PyObject *c, PyObject *d);
+
+static PyObject *
+test_keywords_opt_kwonly(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"a", "b", "c", "d", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_keywords_opt_kwonly", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        b = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    d = args[3];
+skip_optional_kwonly:
+    return_value = test_keywords_opt_kwonly_impl(module, a, b, c, d);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_keywords_opt_kwonly_impl(PyObject *module, PyObject *a, PyObject *b,
+                              PyObject *c, PyObject *d)
+/*[clinic end generated code: output=3f065cb8309b9317 input=209387a4815e5082]*/
+
+
+/*[clinic input]
+test_keywords_kwonly_opt
+
+    a: object
+    *
+    b: object = None
+    c: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_keywords_kwonly_opt__doc__,
+"test_keywords_kwonly_opt($module, /, a, *, b=None, c=None)\n"
+"--\n"
+"\n");
+
+#define TEST_KEYWORDS_KWONLY_OPT_METHODDEF    \
+    {"test_keywords_kwonly_opt", (PyCFunction)(void(*)(void))test_keywords_kwonly_opt, METH_FASTCALL|METH_KEYWORDS, test_keywords_kwonly_opt__doc__},
+
+static PyObject *
+test_keywords_kwonly_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                              PyObject *c);
+
+static PyObject *
+test_keywords_kwonly_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"a", "b", "c", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_keywords_kwonly_opt", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[1]) {
+        b = args[1];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    c = args[2];
+skip_optional_kwonly:
+    return_value = test_keywords_kwonly_opt_impl(module, a, b, c);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_keywords_kwonly_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                              PyObject *c)
+/*[clinic end generated code: output=94edba5484e1681e input=18393cc64fa000f4]*/
+
+
+/*[clinic input]
+test_posonly_keywords
+
+    a: object
+    /
+    b: object
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords__doc__,
+"test_posonly_keywords($module, a, /, b)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_METHODDEF    \
+    {"test_posonly_keywords", (PyCFunction)(void(*)(void))test_posonly_keywords, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords__doc__},
+
+static PyObject *
+test_posonly_keywords_impl(PyObject *module, PyObject *a, PyObject *b);
+
+static PyObject *
+test_posonly_keywords(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords", 0};
+    PyObject *argsbuf[2];
+    PyObject *a;
+    PyObject *b;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    return_value = test_posonly_keywords_impl(module, a, b);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_impl(PyObject *module, PyObject *a, PyObject *b)
+/*[clinic end generated code: output=eca1507f0182ffb0 input=1767b0ebdf06060e]*/
+
+
+/*[clinic input]
+test_posonly_kwonly
+
+    a: object
+    /
+    *
+    c: object
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_kwonly__doc__,
+"test_posonly_kwonly($module, a, /, *, c)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KWONLY_METHODDEF    \
+    {"test_posonly_kwonly", (PyCFunction)(void(*)(void))test_posonly_kwonly, METH_FASTCALL|METH_KEYWORDS, test_posonly_kwonly__doc__},
+
+static PyObject *
+test_posonly_kwonly_impl(PyObject *module, PyObject *a, PyObject *c);
+
+static PyObject *
+test_posonly_kwonly(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "c", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_kwonly", 0};
+    PyObject *argsbuf[2];
+    PyObject *a;
+    PyObject *c;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 1, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    c = args[1];
+    return_value = test_posonly_kwonly_impl(module, a, c);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_kwonly_impl(PyObject *module, PyObject *a, PyObject *c)
+/*[clinic end generated code: output=3e14655646b66e9a input=9042f2818f664839]*/
+
+
+/*[clinic input]
+test_posonly_keywords_kwonly
+
+    a: object
+    /
+    b: object
+    *
+    c: object
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords_kwonly__doc__,
+"test_posonly_keywords_kwonly($module, a, /, b, *, c)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_KWONLY_METHODDEF    \
+    {"test_posonly_keywords_kwonly", (PyCFunction)(void(*)(void))test_posonly_keywords_kwonly, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords_kwonly__doc__},
+
+static PyObject *
+test_posonly_keywords_kwonly_impl(PyObject *module, PyObject *a, PyObject *b,
+                                  PyObject *c);
+
+static PyObject *
+test_posonly_keywords_kwonly(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords_kwonly", 0};
+    PyObject *argsbuf[3];
+    PyObject *a;
+    PyObject *b;
+    PyObject *c;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 1, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    c = args[2];
+    return_value = test_posonly_keywords_kwonly_impl(module, a, b, c);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_kwonly_impl(PyObject *module, PyObject *a, PyObject *b,
+                                  PyObject *c)
+/*[clinic end generated code: output=de57172fc97a626e input=29546ebdca492fea]*/
+
+
+/*[clinic input]
+test_posonly_keywords_opt
+
+    a: object
+    /
+    b: object
+    c: object = None
+    d: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords_opt__doc__,
+"test_posonly_keywords_opt($module, a, /, b, c=None, d=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_OPT_METHODDEF    \
+    {"test_posonly_keywords_opt", (PyCFunction)(void(*)(void))test_posonly_keywords_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords_opt__doc__},
+
+static PyObject *
+test_posonly_keywords_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                               PyObject *c, PyObject *d);
+
+static PyObject *
+test_posonly_keywords_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", "d", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords_opt", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
+    PyObject *a;
+    PyObject *b;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 4, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    d = args[3];
+skip_optional_pos:
+    return_value = test_posonly_keywords_opt_impl(module, a, b, c, d);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                               PyObject *c, PyObject *d)
+/*[clinic end generated code: output=8bc6b44a25d4b716 input=cdf5a9625e554e9b]*/
+
+
+/*[clinic input]
+test_posonly_keywords_opt2
+
+    a: object
+    /
+    b: object = None
+    c: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords_opt2__doc__,
+"test_posonly_keywords_opt2($module, a, /, b=None, c=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_OPT2_METHODDEF    \
+    {"test_posonly_keywords_opt2", (PyCFunction)(void(*)(void))test_posonly_keywords_opt2, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords_opt2__doc__},
+
+static PyObject *
+test_posonly_keywords_opt2_impl(PyObject *module, PyObject *a, PyObject *b,
+                                PyObject *c);
+
+static PyObject *
+test_posonly_keywords_opt2(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords_opt2", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        b = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    c = args[2];
+skip_optional_pos:
+    return_value = test_posonly_keywords_opt2_impl(module, a, b, c);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_opt2_impl(PyObject *module, PyObject *a, PyObject *b,
+                                PyObject *c)
+/*[clinic end generated code: output=a870c45a6510ba91 input=1581299d21d16f14]*/
+
+
+/*[clinic input]
+test_posonly_opt_keywords_opt
+
+    a: object
+    b: object = None
+    /
+    c: object = None
+    d: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_opt_keywords_opt__doc__,
+"test_posonly_opt_keywords_opt($module, a, b=None, /, c=None, d=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_OPT_KEYWORDS_OPT_METHODDEF    \
+    {"test_posonly_opt_keywords_opt", (PyCFunction)(void(*)(void))test_posonly_opt_keywords_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_opt_keywords_opt__doc__},
+
+static PyObject *
+test_posonly_opt_keywords_opt_impl(PyObject *module, PyObject *a,
+                                   PyObject *b, PyObject *c, PyObject *d);
+
+static PyObject *
+test_posonly_opt_keywords_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "", "c", "d", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_opt_keywords_opt", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 4, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (nargs < 2) {
+        goto skip_optional_posonly;
+    }
+    noptargs--;
+    b = args[1];
+skip_optional_posonly:
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    d = args[3];
+skip_optional_pos:
+    return_value = test_posonly_opt_keywords_opt_impl(module, a, b, c, d);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_opt_keywords_opt_impl(PyObject *module, PyObject *a,
+                                   PyObject *b, PyObject *c, PyObject *d)
+/*[clinic end generated code: output=9ae3d52e071d3b7f input=408798ec3d42949f]*/
+
+
+/*[clinic input]
+test_posonly_kwonly_opt
+
+    a: object
+    /
+    *
+    b: object
+    c: object = None
+    d: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_kwonly_opt__doc__,
+"test_posonly_kwonly_opt($module, a, /, *, b, c=None, d=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KWONLY_OPT_METHODDEF    \
+    {"test_posonly_kwonly_opt", (PyCFunction)(void(*)(void))test_posonly_kwonly_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_kwonly_opt__doc__},
+
+static PyObject *
+test_posonly_kwonly_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                             PyObject *c, PyObject *d);
+
+static PyObject *
+test_posonly_kwonly_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", "d", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_kwonly_opt", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
+    PyObject *a;
+    PyObject *b;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 1, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    d = args[3];
+skip_optional_kwonly:
+    return_value = test_posonly_kwonly_opt_impl(module, a, b, c, d);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_kwonly_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                             PyObject *c, PyObject *d)
+/*[clinic end generated code: output=fb001f586ba68549 input=8d8e5643bbbc2309]*/
+
+
+/*[clinic input]
+test_posonly_kwonly_opt2
+
+    a: object
+    /
+    *
+    b: object = None
+    c: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_kwonly_opt2__doc__,
+"test_posonly_kwonly_opt2($module, a, /, *, b=None, c=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KWONLY_OPT2_METHODDEF    \
+    {"test_posonly_kwonly_opt2", (PyCFunction)(void(*)(void))test_posonly_kwonly_opt2, METH_FASTCALL|METH_KEYWORDS, test_posonly_kwonly_opt2__doc__},
+
+static PyObject *
+test_posonly_kwonly_opt2_impl(PyObject *module, PyObject *a, PyObject *b,
+                              PyObject *c);
+
+static PyObject *
+test_posonly_kwonly_opt2(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_kwonly_opt2", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[1]) {
+        b = args[1];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    c = args[2];
+skip_optional_kwonly:
+    return_value = test_posonly_kwonly_opt2_impl(module, a, b, c);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_kwonly_opt2_impl(PyObject *module, PyObject *a, PyObject *b,
+                              PyObject *c)
+/*[clinic end generated code: output=51aae7cac77b458a input=f7e5eed94f75fff0]*/
+
+
+/*[clinic input]
+test_posonly_opt_kwonly_opt
+
+    a: object
+    b: object = None
+    /
+    *
+    c: object = None
+    d: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_opt_kwonly_opt__doc__,
+"test_posonly_opt_kwonly_opt($module, a, b=None, /, *, c=None, d=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_OPT_KWONLY_OPT_METHODDEF    \
+    {"test_posonly_opt_kwonly_opt", (PyCFunction)(void(*)(void))test_posonly_opt_kwonly_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_opt_kwonly_opt__doc__},
+
+static PyObject *
+test_posonly_opt_kwonly_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                                 PyObject *c, PyObject *d);
+
+static PyObject *
+test_posonly_opt_kwonly_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "", "c", "d", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_opt_kwonly_opt", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (nargs < 2) {
+        goto skip_optional_posonly;
+    }
+    noptargs--;
+    b = args[1];
+skip_optional_posonly:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    d = args[3];
+skip_optional_kwonly:
+    return_value = test_posonly_opt_kwonly_opt_impl(module, a, b, c, d);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_opt_kwonly_opt_impl(PyObject *module, PyObject *a, PyObject *b,
+                                 PyObject *c, PyObject *d)
+/*[clinic end generated code: output=68844c45143d1668 input=1e557dc979d120fd]*/
+
+
+/*[clinic input]
+test_posonly_keywords_kwonly_opt
+
+    a: object
+    /
+    b: object
+    *
+    c: object
+    d: object = None
+    e: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords_kwonly_opt__doc__,
+"test_posonly_keywords_kwonly_opt($module, a, /, b, *, c, d=None, e=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_KWONLY_OPT_METHODDEF    \
+    {"test_posonly_keywords_kwonly_opt", (PyCFunction)(void(*)(void))test_posonly_keywords_kwonly_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords_kwonly_opt__doc__},
+
+static PyObject *
+test_posonly_keywords_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                      PyObject *b, PyObject *c, PyObject *d,
+                                      PyObject *e);
+
+static PyObject *
+test_posonly_keywords_kwonly_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", "d", "e", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords_kwonly_opt", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
+    PyObject *a;
+    PyObject *b;
+    PyObject *c;
+    PyObject *d = Py_None;
+    PyObject *e = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 1, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    c = args[2];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[3]) {
+        d = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    e = args[4];
+skip_optional_kwonly:
+    return_value = test_posonly_keywords_kwonly_opt_impl(module, a, b, c, d, e);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                      PyObject *b, PyObject *c, PyObject *d,
+                                      PyObject *e)
+/*[clinic end generated code: output=996ff645551897ac input=c3884a4f956fdc89]*/
+
+
+/*[clinic input]
+test_posonly_keywords_kwonly_opt2
+
+    a: object
+    /
+    b: object
+    *
+    c: object = None
+    d: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords_kwonly_opt2__doc__,
+"test_posonly_keywords_kwonly_opt2($module, a, /, b, *, c=None, d=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_KWONLY_OPT2_METHODDEF    \
+    {"test_posonly_keywords_kwonly_opt2", (PyCFunction)(void(*)(void))test_posonly_keywords_kwonly_opt2, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords_kwonly_opt2__doc__},
+
+static PyObject *
+test_posonly_keywords_kwonly_opt2_impl(PyObject *module, PyObject *a,
+                                       PyObject *b, PyObject *c, PyObject *d);
+
+static PyObject *
+test_posonly_keywords_kwonly_opt2(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", "d", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords_kwonly_opt2", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
+    PyObject *a;
+    PyObject *b;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    d = args[3];
+skip_optional_kwonly:
+    return_value = test_posonly_keywords_kwonly_opt2_impl(module, a, b, c, d);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_kwonly_opt2_impl(PyObject *module, PyObject *a,
+                                       PyObject *b, PyObject *c, PyObject *d)
+/*[clinic end generated code: output=e5a3e992fd4b28b3 input=68d01d7c0f6dafb0]*/
+
+
+/*[clinic input]
+test_posonly_keywords_opt_kwonly_opt
+
+    a: object
+    /
+    b: object
+    c: object = None
+    *
+    d: object = None
+    e: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords_opt_kwonly_opt__doc__,
+"test_posonly_keywords_opt_kwonly_opt($module, a, /, b, c=None, *,\n"
+"                                     d=None, e=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_OPT_KWONLY_OPT_METHODDEF    \
+    {"test_posonly_keywords_opt_kwonly_opt", (PyCFunction)(void(*)(void))test_posonly_keywords_opt_kwonly_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords_opt_kwonly_opt__doc__},
+
+static PyObject *
+test_posonly_keywords_opt_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                          PyObject *b, PyObject *c,
+                                          PyObject *d, PyObject *e);
+
+static PyObject *
+test_posonly_keywords_opt_kwonly_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", "d", "e", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords_opt_kwonly_opt", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
+    PyObject *a;
+    PyObject *b;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+    PyObject *e = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    b = args[1];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[3]) {
+        d = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    e = args[4];
+skip_optional_kwonly:
+    return_value = test_posonly_keywords_opt_kwonly_opt_impl(module, a, b, c, d, e);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_opt_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                          PyObject *b, PyObject *c,
+                                          PyObject *d, PyObject *e)
+/*[clinic end generated code: output=ff9fb6c3d2cbbaa4 input=d0883d45876f186c]*/
+
+
+/*[clinic input]
+test_posonly_keywords_opt2_kwonly_opt
+
+    a: object
+    /
+    b: object = None
+    c: object = None
+    *
+    d: object = None
+    e: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_keywords_opt2_kwonly_opt__doc__,
+"test_posonly_keywords_opt2_kwonly_opt($module, a, /, b=None, c=None, *,\n"
+"                                      d=None, e=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_KEYWORDS_OPT2_KWONLY_OPT_METHODDEF    \
+    {"test_posonly_keywords_opt2_kwonly_opt", (PyCFunction)(void(*)(void))test_posonly_keywords_opt2_kwonly_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_keywords_opt2_kwonly_opt__doc__},
+
+static PyObject *
+test_posonly_keywords_opt2_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                           PyObject *b, PyObject *c,
+                                           PyObject *d, PyObject *e);
+
+static PyObject *
+test_posonly_keywords_opt2_kwonly_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "b", "c", "d", "e", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_keywords_opt2_kwonly_opt", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+    PyObject *e = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        b = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[3]) {
+        d = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    e = args[4];
+skip_optional_kwonly:
+    return_value = test_posonly_keywords_opt2_kwonly_opt_impl(module, a, b, c, d, e);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_keywords_opt2_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                           PyObject *b, PyObject *c,
+                                           PyObject *d, PyObject *e)
+/*[clinic end generated code: output=c809d7a84a2205e1 input=c95e2e1ec93035ad]*/
+
+
+/*[clinic input]
+test_posonly_opt_keywords_opt_kwonly_opt
+
+    a: object
+    b: object = None
+    /
+    c: object = None
+    d: object = None
+    *
+    e: object = None
+    f: object = None
+
+[clinic start generated code]*/
+
+PyDoc_STRVAR(test_posonly_opt_keywords_opt_kwonly_opt__doc__,
+"test_posonly_opt_keywords_opt_kwonly_opt($module, a, b=None, /, c=None,\n"
+"                                         d=None, *, e=None, f=None)\n"
+"--\n"
+"\n");
+
+#define TEST_POSONLY_OPT_KEYWORDS_OPT_KWONLY_OPT_METHODDEF    \
+    {"test_posonly_opt_keywords_opt_kwonly_opt", (PyCFunction)(void(*)(void))test_posonly_opt_keywords_opt_kwonly_opt, METH_FASTCALL|METH_KEYWORDS, test_posonly_opt_keywords_opt_kwonly_opt__doc__},
+
+static PyObject *
+test_posonly_opt_keywords_opt_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                              PyObject *b, PyObject *c,
+                                              PyObject *d, PyObject *e,
+                                              PyObject *f);
+
+static PyObject *
+test_posonly_opt_keywords_opt_kwonly_opt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"", "", "c", "d", "e", "f", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "test_posonly_opt_keywords_opt_kwonly_opt", 0};
+    PyObject *argsbuf[6];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    PyObject *a;
+    PyObject *b = Py_None;
+    PyObject *c = Py_None;
+    PyObject *d = Py_None;
+    PyObject *e = Py_None;
+    PyObject *f = Py_None;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 4, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    a = args[0];
+    if (nargs < 2) {
+        goto skip_optional_posonly;
+    }
+    noptargs--;
+    b = args[1];
+skip_optional_posonly:
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        c = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[3]) {
+        d = args[3];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[4]) {
+        e = args[4];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    f = args[5];
+skip_optional_kwonly:
+    return_value = test_posonly_opt_keywords_opt_kwonly_opt_impl(module, a, b, c, d, e, f);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+test_posonly_opt_keywords_opt_kwonly_opt_impl(PyObject *module, PyObject *a,
+                                              PyObject *b, PyObject *c,
+                                              PyObject *d, PyObject *e,
+                                              PyObject *f)
+/*[clinic end generated code: output=719e4f6c224402d4 input=9914857713c5bbf8]*/
diff --git a/Modules/_blake2/clinic/blake2b_impl.c.h b/Modules/_blake2/clinic/blake2b_impl.c.h
index 3315bf9490..09fe00457f 100644
--- a/Modules/_blake2/clinic/blake2b_impl.c.h
+++ b/Modules/_blake2/clinic/blake2b_impl.c.h
@@ -22,7 +22,11 @@ py_blake2b_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "digest_size", "key", "salt", "person", "fanout", "depth", "leaf_size", "node_offset", "node_depth", "inner_size", "last_node", NULL};
-    static _PyArg_Parser _parser = {"|O$iy*y*y*iiO&O&iip:blake2b", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "blake2b", 0};
+    PyObject *argsbuf[12];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *data = NULL;
     int digest_size = BLAKE2B_OUTBYTES;
     Py_buffer key = {NULL, NULL};
@@ -36,10 +40,146 @@ py_blake2b_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     int inner_size = 0;
     int last_node = 0;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &data, &digest_size, &key, &salt, &person, &fanout, &depth, _PyLong_UnsignedLong_Converter, &leaf_size, _PyLong_UnsignedLongLong_Converter, &node_offset, &node_depth, &inner_size, &last_node)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (nargs < 1) {
+        goto skip_optional_posonly;
+    }
+    noptargs--;
+    data = fastargs[0];
+skip_optional_posonly:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (fastargs[1]) {
+        if (PyFloat_Check(fastargs[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        digest_size = _PyLong_AsInt(fastargs[1]);
+        if (digest_size == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[2]) {
+        if (PyObject_GetBuffer(fastargs[2], &key, PyBUF_SIMPLE) != 0) {
+            goto exit;
+        }
+        if (!PyBuffer_IsContiguous(&key, 'C')) {
+            _PyArg_BadArgument("blake2b", 3, "contiguous buffer", fastargs[2]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[3]) {
+        if (PyObject_GetBuffer(fastargs[3], &salt, PyBUF_SIMPLE) != 0) {
+            goto exit;
+        }
+        if (!PyBuffer_IsContiguous(&salt, 'C')) {
+            _PyArg_BadArgument("blake2b", 4, "contiguous buffer", fastargs[3]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[4]) {
+        if (PyObject_GetBuffer(fastargs[4], &person, PyBUF_SIMPLE) != 0) {
+            goto exit;
+        }
+        if (!PyBuffer_IsContiguous(&person, 'C')) {
+            _PyArg_BadArgument("blake2b", 5, "contiguous buffer", fastargs[4]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[5]) {
+        if (PyFloat_Check(fastargs[5])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        fanout = _PyLong_AsInt(fastargs[5]);
+        if (fanout == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[6]) {
+        if (PyFloat_Check(fastargs[6])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        depth = _PyLong_AsInt(fastargs[6]);
+        if (depth == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[7]) {
+        if (!_PyLong_UnsignedLong_Converter(fastargs[7], &leaf_size)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[8]) {
+        if (!_PyLong_UnsignedLongLong_Converter(fastargs[8], &node_offset)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[9]) {
+        if (PyFloat_Check(fastargs[9])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        node_depth = _PyLong_AsInt(fastargs[9]);
+        if (node_depth == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[10]) {
+        if (PyFloat_Check(fastargs[10])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        inner_size = _PyLong_AsInt(fastargs[10]);
+        if (inner_size == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    last_node = PyObject_IsTrue(fastargs[11]);
+    if (last_node < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = py_blake2b_new_impl(type, data, digest_size, &key, &salt, &person, fanout, depth, leaf_size, node_offset, node_depth, inner_size, last_node);
 
 exit:
@@ -121,4 +261,4 @@ _blake2_blake2b_hexdigest(BLAKE2bObject *self, PyObject *Py_UNUSED(ignored))
 {
     return _blake2_blake2b_hexdigest_impl(self);
 }
-/*[clinic end generated code: output=39c77de2142faa12 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=a91d182ce1109f34 input=a9049054013a1b77]*/
diff --git a/Modules/_blake2/clinic/blake2s_impl.c.h b/Modules/_blake2/clinic/blake2s_impl.c.h
index 23d19ecc9c..92739a1feb 100644
--- a/Modules/_blake2/clinic/blake2s_impl.c.h
+++ b/Modules/_blake2/clinic/blake2s_impl.c.h
@@ -22,7 +22,11 @@ py_blake2s_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "digest_size", "key", "salt", "person", "fanout", "depth", "leaf_size", "node_offset", "node_depth", "inner_size", "last_node", NULL};
-    static _PyArg_Parser _parser = {"|O$iy*y*y*iiO&O&iip:blake2s", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "blake2s", 0};
+    PyObject *argsbuf[12];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *data = NULL;
     int digest_size = BLAKE2S_OUTBYTES;
     Py_buffer key = {NULL, NULL};
@@ -36,10 +40,146 @@ py_blake2s_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     int inner_size = 0;
     int last_node = 0;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &data, &digest_size, &key, &salt, &person, &fanout, &depth, _PyLong_UnsignedLong_Converter, &leaf_size, _PyLong_UnsignedLongLong_Converter, &node_offset, &node_depth, &inner_size, &last_node)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (nargs < 1) {
+        goto skip_optional_posonly;
+    }
+    noptargs--;
+    data = fastargs[0];
+skip_optional_posonly:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (fastargs[1]) {
+        if (PyFloat_Check(fastargs[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        digest_size = _PyLong_AsInt(fastargs[1]);
+        if (digest_size == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[2]) {
+        if (PyObject_GetBuffer(fastargs[2], &key, PyBUF_SIMPLE) != 0) {
+            goto exit;
+        }
+        if (!PyBuffer_IsContiguous(&key, 'C')) {
+            _PyArg_BadArgument("blake2s", 3, "contiguous buffer", fastargs[2]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[3]) {
+        if (PyObject_GetBuffer(fastargs[3], &salt, PyBUF_SIMPLE) != 0) {
+            goto exit;
+        }
+        if (!PyBuffer_IsContiguous(&salt, 'C')) {
+            _PyArg_BadArgument("blake2s", 4, "contiguous buffer", fastargs[3]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[4]) {
+        if (PyObject_GetBuffer(fastargs[4], &person, PyBUF_SIMPLE) != 0) {
+            goto exit;
+        }
+        if (!PyBuffer_IsContiguous(&person, 'C')) {
+            _PyArg_BadArgument("blake2s", 5, "contiguous buffer", fastargs[4]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[5]) {
+        if (PyFloat_Check(fastargs[5])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        fanout = _PyLong_AsInt(fastargs[5]);
+        if (fanout == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[6]) {
+        if (PyFloat_Check(fastargs[6])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        depth = _PyLong_AsInt(fastargs[6]);
+        if (depth == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[7]) {
+        if (!_PyLong_UnsignedLong_Converter(fastargs[7], &leaf_size)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[8]) {
+        if (!_PyLong_UnsignedLongLong_Converter(fastargs[8], &node_offset)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[9]) {
+        if (PyFloat_Check(fastargs[9])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        node_depth = _PyLong_AsInt(fastargs[9]);
+        if (node_depth == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[10]) {
+        if (PyFloat_Check(fastargs[10])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        inner_size = _PyLong_AsInt(fastargs[10]);
+        if (inner_size == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    last_node = PyObject_IsTrue(fastargs[11]);
+    if (last_node < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = py_blake2s_new_impl(type, data, digest_size, &key, &salt, &person, fanout, depth, leaf_size, node_offset, node_depth, inner_size, last_node);
 
 exit:
@@ -121,4 +261,4 @@ _blake2_blake2s_hexdigest(BLAKE2sObject *self, PyObject *Py_UNUSED(ignored))
 {
     return _blake2_blake2s_hexdigest_impl(self);
 }
-/*[clinic end generated code: output=a31a1d56f0e0781f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=ae8e9b7301d092b4 input=a9049054013a1b77]*/
diff --git a/Modules/_io/clinic/_iomodule.c.h b/Modules/_io/clinic/_iomodule.c.h
index f03e84e431..990c81c355 100644
--- a/Modules/_io/clinic/_iomodule.c.h
+++ b/Modules/_io/clinic/_iomodule.c.h
@@ -139,7 +139,9 @@ _io_open(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"file", "mode", "buffering", "encoding", "errors", "newline", "closefd", "opener", NULL};
-    static _PyArg_Parser _parser = {"O|sizzziO:open", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "open", 0};
+    PyObject *argsbuf[8];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *file;
     const char *mode = "r";
     int buffering = -1;
@@ -149,13 +151,134 @@ _io_open(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
     int closefd = 1;
     PyObject *opener = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &file, &mode, &buffering, &encoding, &errors, &newline, &closefd, &opener)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 8, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    file = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (!PyUnicode_Check(args[1])) {
+            _PyArg_BadArgument("open", 2, "str", args[1]);
+            goto exit;
+        }
+        Py_ssize_t mode_length;
+        mode = PyUnicode_AsUTF8AndSize(args[1], &mode_length);
+        if (mode == NULL) {
+            goto exit;
+        }
+        if (strlen(mode) != (size_t)mode_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[2]) {
+        if (PyFloat_Check(args[2])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        buffering = _PyLong_AsInt(args[2]);
+        if (buffering == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[3]) {
+        if (args[3] == Py_None) {
+            encoding = NULL;
+        }
+        else if (PyUnicode_Check(args[3])) {
+            Py_ssize_t encoding_length;
+            encoding = PyUnicode_AsUTF8AndSize(args[3], &encoding_length);
+            if (encoding == NULL) {
+                goto exit;
+            }
+            if (strlen(encoding) != (size_t)encoding_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("open", 4, "str or None", args[3]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[4]) {
+        if (args[4] == Py_None) {
+            errors = NULL;
+        }
+        else if (PyUnicode_Check(args[4])) {
+            Py_ssize_t errors_length;
+            errors = PyUnicode_AsUTF8AndSize(args[4], &errors_length);
+            if (errors == NULL) {
+                goto exit;
+            }
+            if (strlen(errors) != (size_t)errors_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("open", 5, "str or None", args[4]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[5]) {
+        if (args[5] == Py_None) {
+            newline = NULL;
+        }
+        else if (PyUnicode_Check(args[5])) {
+            Py_ssize_t newline_length;
+            newline = PyUnicode_AsUTF8AndSize(args[5], &newline_length);
+            if (newline == NULL) {
+                goto exit;
+            }
+            if (strlen(newline) != (size_t)newline_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("open", 6, "str or None", args[5]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[6]) {
+        if (PyFloat_Check(args[6])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        closefd = _PyLong_AsInt(args[6]);
+        if (closefd == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    opener = args[7];
+skip_optional_pos:
     return_value = _io_open_impl(module, file, mode, buffering, encoding, errors, newline, closefd, opener);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=a2c1af38d943ccec input=a9049054013a1b77]*/
+/*[clinic end generated code: output=19fc9b69a5166f63 input=a9049054013a1b77]*/
diff --git a/Modules/_io/clinic/bufferedio.c.h b/Modules/_io/clinic/bufferedio.c.h
index 60a6dac742..d5e8c8a748 100644
--- a/Modules/_io/clinic/bufferedio.c.h
+++ b/Modules/_io/clinic/bufferedio.c.h
@@ -418,14 +418,40 @@ _io_BufferedReader___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"raw", "buffer_size", NULL};
-    static _PyArg_Parser _parser = {"O|n:BufferedReader", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "BufferedReader", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *raw;
     Py_ssize_t buffer_size = DEFAULT_BUFFER_SIZE;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &raw, &buffer_size)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    raw = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(fastargs[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(fastargs[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        buffer_size = ival;
+    }
+skip_optional_pos:
     return_value = _io_BufferedReader___init___impl((buffered *)self, raw, buffer_size);
 
 exit:
@@ -451,14 +477,40 @@ _io_BufferedWriter___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"raw", "buffer_size", NULL};
-    static _PyArg_Parser _parser = {"O|n:BufferedWriter", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "BufferedWriter", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *raw;
     Py_ssize_t buffer_size = DEFAULT_BUFFER_SIZE;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &raw, &buffer_size)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    raw = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(fastargs[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(fastargs[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        buffer_size = ival;
+    }
+skip_optional_pos:
     return_value = _io_BufferedWriter___init___impl((buffered *)self, raw, buffer_size);
 
 exit:
@@ -581,17 +633,43 @@ _io_BufferedRandom___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"raw", "buffer_size", NULL};
-    static _PyArg_Parser _parser = {"O|n:BufferedRandom", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "BufferedRandom", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *raw;
     Py_ssize_t buffer_size = DEFAULT_BUFFER_SIZE;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &raw, &buffer_size)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    raw = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(fastargs[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(fastargs[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        buffer_size = ival;
+    }
+skip_optional_pos:
     return_value = _io_BufferedRandom___init___impl((buffered *)self, raw, buffer_size);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=b7f51040defff318 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b22b4aedd53c340a input=a9049054013a1b77]*/
diff --git a/Modules/_io/clinic/bytesio.c.h b/Modules/_io/clinic/bytesio.c.h
index 54c5123a00..8dd68f5613 100644
--- a/Modules/_io/clinic/bytesio.c.h
+++ b/Modules/_io/clinic/bytesio.c.h
@@ -494,16 +494,25 @@ _io_BytesIO___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"initial_bytes", NULL};
-    static _PyArg_Parser _parser = {"|O:BytesIO", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "BytesIO", 0};
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *initvalue = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &initvalue)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    initvalue = fastargs[0];
+skip_optional_pos:
     return_value = _io_BytesIO___init___impl((bytesio *)self, initvalue);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=a6b47dd7921abfcd input=a9049054013a1b77]*/
+/*[clinic end generated code: output=22e8fb54874b6ee5 input=a9049054013a1b77]*/
diff --git a/Modules/_io/clinic/fileio.c.h b/Modules/_io/clinic/fileio.c.h
index e7d49d47f8..8016e98886 100644
--- a/Modules/_io/clinic/fileio.c.h
+++ b/Modules/_io/clinic/fileio.c.h
@@ -50,16 +50,58 @@ _io_FileIO___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"file", "mode", "closefd", "opener", NULL};
-    static _PyArg_Parser _parser = {"O|siO:FileIO", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "FileIO", 0};
+    PyObject *argsbuf[4];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *nameobj;
     const char *mode = "r";
     int closefd = 1;
     PyObject *opener = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &nameobj, &mode, &closefd, &opener)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 4, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    nameobj = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[1]) {
+        if (!PyUnicode_Check(fastargs[1])) {
+            _PyArg_BadArgument("FileIO", 2, "str", fastargs[1]);
+            goto exit;
+        }
+        Py_ssize_t mode_length;
+        mode = PyUnicode_AsUTF8AndSize(fastargs[1], &mode_length);
+        if (mode == NULL) {
+            goto exit;
+        }
+        if (strlen(mode) != (size_t)mode_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[2]) {
+        if (PyFloat_Check(fastargs[2])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        closefd = _PyLong_AsInt(fastargs[2]);
+        if (closefd == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    opener = fastargs[3];
+skip_optional_pos:
     return_value = _io_FileIO___init___impl((fileio *)self, nameobj, mode, closefd, opener);
 
 exit:
@@ -405,4 +447,4 @@ _io_FileIO_isatty(fileio *self, PyObject *Py_UNUSED(ignored))
 #ifndef _IO_FILEIO_TRUNCATE_METHODDEF
     #define _IO_FILEIO_TRUNCATE_METHODDEF
 #endif /* !defined(_IO_FILEIO_TRUNCATE_METHODDEF) */
-/*[clinic end generated code: output=b6f327457938d4dd input=a9049054013a1b77]*/
+/*[clinic end generated code: output=7ee4f3ae584fc6d2 input=a9049054013a1b77]*/
diff --git a/Modules/_io/clinic/stringio.c.h b/Modules/_io/clinic/stringio.c.h
index 1757d83ef7..77a720c2a6 100644
--- a/Modules/_io/clinic/stringio.c.h
+++ b/Modules/_io/clinic/stringio.c.h
@@ -266,14 +266,29 @@ _io_StringIO___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"initial_value", "newline", NULL};
-    static _PyArg_Parser _parser = {"|OO:StringIO", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "StringIO", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *value = NULL;
     PyObject *newline_obj = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &value, &newline_obj)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[0]) {
+        value = fastargs[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    newline_obj = fastargs[1];
+skip_optional_pos:
     return_value = _io_StringIO___init___impl((stringio *)self, value, newline_obj);
 
 exit:
@@ -333,4 +348,4 @@ _io_StringIO_seekable(stringio *self, PyObject *Py_UNUSED(ignored))
 {
     return _io_StringIO_seekable_impl(self);
 }
-/*[clinic end generated code: output=db5e51dcc4dae8d5 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=7aad5ab2e64a25b8 input=a9049054013a1b77]*/
diff --git a/Modules/_io/clinic/textio.c.h b/Modules/_io/clinic/textio.c.h
index 2a13abfd96..cec9defea0 100644
--- a/Modules/_io/clinic/textio.c.h
+++ b/Modules/_io/clinic/textio.c.h
@@ -25,15 +25,34 @@ _io_IncrementalNewlineDecoder___init__(PyObject *self, PyObject *args, PyObject
 {
     int return_value = -1;
     static const char * const _keywords[] = {"decoder", "translate", "errors", NULL};
-    static _PyArg_Parser _parser = {"Oi|O:IncrementalNewlineDecoder", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "IncrementalNewlineDecoder", 0};
+    PyObject *argsbuf[3];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 2;
     PyObject *decoder;
     int translate;
     PyObject *errors = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &decoder, &translate, &errors)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 2, 3, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    decoder = fastargs[0];
+    if (PyFloat_Check(fastargs[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    translate = _PyLong_AsInt(fastargs[1]);
+    if (translate == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    errors = fastargs[2];
+skip_optional_pos:
     return_value = _io_IncrementalNewlineDecoder___init___impl((nldecoder_object *)self, decoder, translate, errors);
 
 exit:
@@ -57,14 +76,30 @@ _io_IncrementalNewlineDecoder_decode(nldecoder_object *self, PyObject *const *ar
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"input", "final", NULL};
-    static _PyArg_Parser _parser = {"O|i:decode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *input;
     int final = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &input, &final)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    input = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    final = _PyLong_AsInt(args[1]);
+    if (final == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _io_IncrementalNewlineDecoder_decode_impl(self, input, final);
 
 exit:
@@ -158,7 +193,11 @@ _io_TextIOWrapper___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"buffer", "encoding", "errors", "newline", "line_buffering", "write_through", NULL};
-    static _PyArg_Parser _parser = {"O|zOzii:TextIOWrapper", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "TextIOWrapper", 0};
+    PyObject *argsbuf[6];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *buffer;
     const char *encoding = NULL;
     PyObject *errors = Py_None;
@@ -166,10 +205,90 @@ _io_TextIOWrapper___init__(PyObject *self, PyObject *args, PyObject *kwargs)
     int line_buffering = 0;
     int write_through = 0;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &buffer, &encoding, &errors, &newline, &line_buffering, &write_through)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 6, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    buffer = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[1]) {
+        if (fastargs[1] == Py_None) {
+            encoding = NULL;
+        }
+        else if (PyUnicode_Check(fastargs[1])) {
+            Py_ssize_t encoding_length;
+            encoding = PyUnicode_AsUTF8AndSize(fastargs[1], &encoding_length);
+            if (encoding == NULL) {
+                goto exit;
+            }
+            if (strlen(encoding) != (size_t)encoding_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("TextIOWrapper", 2, "str or None", fastargs[1]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[2]) {
+        errors = fastargs[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[3]) {
+        if (fastargs[3] == Py_None) {
+            newline = NULL;
+        }
+        else if (PyUnicode_Check(fastargs[3])) {
+            Py_ssize_t newline_length;
+            newline = PyUnicode_AsUTF8AndSize(fastargs[3], &newline_length);
+            if (newline == NULL) {
+                goto exit;
+            }
+            if (strlen(newline) != (size_t)newline_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("TextIOWrapper", 4, "str or None", fastargs[3]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[4]) {
+        if (PyFloat_Check(fastargs[4])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        line_buffering = _PyLong_AsInt(fastargs[4]);
+        if (line_buffering == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(fastargs[5])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    write_through = _PyLong_AsInt(fastargs[5]);
+    if (write_through == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _io_TextIOWrapper___init___impl((textio *)self, buffer, encoding, errors, newline, line_buffering, write_through);
 
 exit:
@@ -199,17 +318,48 @@ _io_TextIOWrapper_reconfigure(textio *self, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"encoding", "errors", "newline", "line_buffering", "write_through", NULL};
-    static _PyArg_Parser _parser = {"|$OOOOO:reconfigure", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "reconfigure", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *encoding = Py_None;
     PyObject *errors = Py_None;
     PyObject *newline_obj = NULL;
     PyObject *line_buffering_obj = Py_None;
     PyObject *write_through_obj = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &encoding, &errors, &newline_obj, &line_buffering_obj, &write_through_obj)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[0]) {
+        encoding = args[0];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[1]) {
+        errors = args[1];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[2]) {
+        newline_obj = args[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[3]) {
+        line_buffering_obj = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    write_through_obj = args[4];
+skip_optional_kwonly:
     return_value = _io_TextIOWrapper_reconfigure_impl(self, encoding, errors, newline_obj, line_buffering_obj, write_through_obj);
 
 exit:
@@ -551,4 +701,4 @@ _io_TextIOWrapper_close(textio *self, PyObject *Py_UNUSED(ignored))
 {
     return _io_TextIOWrapper_close_impl(self);
 }
-/*[clinic end generated code: output=c3d1b2a5d2d2d429 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b651e056e3000f88 input=a9049054013a1b77]*/
diff --git a/Modules/_io/clinic/winconsoleio.c.h b/Modules/_io/clinic/winconsoleio.c.h
index e7cd854ae2..bb0cdc4558 100644
--- a/Modules/_io/clinic/winconsoleio.c.h
+++ b/Modules/_io/clinic/winconsoleio.c.h
@@ -49,16 +49,58 @@ _io__WindowsConsoleIO___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"file", "mode", "closefd", "opener", NULL};
-    static _PyArg_Parser _parser = {"O|siO:_WindowsConsoleIO", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_WindowsConsoleIO", 0};
+    PyObject *argsbuf[4];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *nameobj;
     const char *mode = "r";
     int closefd = 1;
     PyObject *opener = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &nameobj, &mode, &closefd, &opener)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 4, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    nameobj = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[1]) {
+        if (!PyUnicode_Check(fastargs[1])) {
+            _PyArg_BadArgument("_WindowsConsoleIO", 2, "str", fastargs[1]);
+            goto exit;
+        }
+        Py_ssize_t mode_length;
+        mode = PyUnicode_AsUTF8AndSize(fastargs[1], &mode_length);
+        if (mode == NULL) {
+            goto exit;
+        }
+        if (strlen(mode) != (size_t)mode_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[2]) {
+        if (PyFloat_Check(fastargs[2])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        closefd = _PyLong_AsInt(fastargs[2]);
+        if (closefd == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    opener = fastargs[3];
+skip_optional_pos:
     return_value = _io__WindowsConsoleIO___init___impl((winconsoleio *)self, nameobj, mode, closefd, opener);
 
 exit:
@@ -344,4 +386,4 @@ _io__WindowsConsoleIO_isatty(winconsoleio *self, PyObject *Py_UNUSED(ignored))
 #ifndef _IO__WINDOWSCONSOLEIO_ISATTY_METHODDEF
     #define _IO__WINDOWSCONSOLEIO_ISATTY_METHODDEF
 #endif /* !defined(_IO__WINDOWSCONSOLEIO_ISATTY_METHODDEF) */
-/*[clinic end generated code: output=ab0f0ee8062eecb3 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=57bf2c09a42bd330 input=a9049054013a1b77]*/
diff --git a/Modules/_multiprocessing/clinic/posixshmem.c.h b/Modules/_multiprocessing/clinic/posixshmem.c.h
index 20abddc0a2..0ebfa2fe37 100644
--- a/Modules/_multiprocessing/clinic/posixshmem.c.h
+++ b/Modules/_multiprocessing/clinic/posixshmem.c.h
@@ -22,16 +22,48 @@ _posixshmem_shm_open(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "flags", "mode", NULL};
-    static _PyArg_Parser _parser = {"Ui|i:shm_open", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "shm_open", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     PyObject *path;
     int flags;
     int mode = 511;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &path, &flags, &mode)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("shm_open", 1, "str", args[0]);
+        goto exit;
+    }
+    if (PyUnicode_READY(args[0]) == -1) {
+        goto exit;
+    }
+    path = args[0];
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    flags = _PyLong_AsInt(args[1]);
+    if (flags == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    mode = _PyLong_AsInt(args[2]);
+    if (mode == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     _return_value = _posixshmem_shm_open_impl(module, path, flags, mode);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -67,13 +99,22 @@ _posixshmem_shm_unlink(PyObject *module, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"U:shm_unlink", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "shm_unlink", 0};
+    PyObject *argsbuf[1];
     PyObject *path;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("shm_unlink", 1, "str", args[0]);
+        goto exit;
+    }
+    if (PyUnicode_READY(args[0]) == -1) {
         goto exit;
     }
+    path = args[0];
     return_value = _posixshmem_shm_unlink_impl(module, path);
 
 exit:
@@ -89,4 +130,4 @@ exit:
 #ifndef _POSIXSHMEM_SHM_UNLINK_METHODDEF
     #define _POSIXSHMEM_SHM_UNLINK_METHODDEF
 #endif /* !defined(_POSIXSHMEM_SHM_UNLINK_METHODDEF) */
-/*[clinic end generated code: output=ff9cf0bc9b8baddf input=a9049054013a1b77]*/
+/*[clinic end generated code: output=be42e23c18677c0f input=a9049054013a1b77]*/
diff --git a/Modules/cjkcodecs/clinic/multibytecodec.c.h b/Modules/cjkcodecs/clinic/multibytecodec.c.h
index c62a64179b..84774f0076 100644
--- a/Modules/cjkcodecs/clinic/multibytecodec.c.h
+++ b/Modules/cjkcodecs/clinic/multibytecodec.c.h
@@ -26,14 +26,39 @@ _multibytecodec_MultibyteCodec_encode(MultibyteCodecObject *self, PyObject *cons
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"input", "errors", NULL};
-    static _PyArg_Parser _parser = {"O|z:encode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "encode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *input;
     const char *errors = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &input, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    input = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1] == Py_None) {
+        errors = NULL;
+    }
+    else if (PyUnicode_Check(args[1])) {
+        Py_ssize_t errors_length;
+        errors = PyUnicode_AsUTF8AndSize(args[1], &errors_length);
+        if (errors == NULL) {
+            goto exit;
+        }
+        if (strlen(errors) != (size_t)errors_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+    }
+    else {
+        _PyArg_BadArgument("encode", 2, "str or None", args[1]);
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _multibytecodec_MultibyteCodec_encode_impl(self, input, errors);
 
 exit:
@@ -64,14 +89,45 @@ _multibytecodec_MultibyteCodec_decode(MultibyteCodecObject *self, PyObject *cons
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"input", "errors", NULL};
-    static _PyArg_Parser _parser = {"y*|z:decode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer input = {NULL, NULL};
     const char *errors = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &input, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[0], &input, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&input, 'C')) {
+        _PyArg_BadArgument("decode", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1] == Py_None) {
+        errors = NULL;
+    }
+    else if (PyUnicode_Check(args[1])) {
+        Py_ssize_t errors_length;
+        errors = PyUnicode_AsUTF8AndSize(args[1], &errors_length);
+        if (errors == NULL) {
+            goto exit;
+        }
+        if (strlen(errors) != (size_t)errors_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+    }
+    else {
+        _PyArg_BadArgument("decode", 2, "str or None", args[1]);
         goto exit;
     }
+skip_optional_pos:
     return_value = _multibytecodec_MultibyteCodec_decode_impl(self, &input, errors);
 
 exit:
@@ -101,14 +157,30 @@ _multibytecodec_MultibyteIncrementalEncoder_encode(MultibyteIncrementalEncoderOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"input", "final", NULL};
-    static _PyArg_Parser _parser = {"O|i:encode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "encode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *input;
     int final = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &input, &final)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    input = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    final = _PyLong_AsInt(args[1]);
+    if (final == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _multibytecodec_MultibyteIncrementalEncoder_encode_impl(self, input, final);
 
 exit:
@@ -196,14 +268,36 @@ _multibytecodec_MultibyteIncrementalDecoder_decode(MultibyteIncrementalDecoderOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"input", "final", NULL};
-    static _PyArg_Parser _parser = {"y*|i:decode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer input = {NULL, NULL};
     int final = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &input, &final)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[0], &input, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&input, 'C')) {
+        _PyArg_BadArgument("decode", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    final = _PyLong_AsInt(args[1]);
+    if (final == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = _multibytecodec_MultibyteIncrementalDecoder_decode_impl(self, &input, final);
 
 exit:
@@ -431,4 +525,4 @@ PyDoc_STRVAR(_multibytecodec___create_codec__doc__,
 
 #define _MULTIBYTECODEC___CREATE_CODEC_METHODDEF    \
     {"__create_codec", (PyCFunction)_multibytecodec___create_codec, METH_O, _multibytecodec___create_codec__doc__},
-/*[clinic end generated code: output=bcd6311010557faf input=a9049054013a1b77]*/
+/*[clinic end generated code: output=eb95a408c4ddbfff input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_asynciomodule.c.h b/Modules/clinic/_asynciomodule.c.h
index 860b57f9ee..87669f7c9f 100644
--- a/Modules/clinic/_asynciomodule.c.h
+++ b/Modules/clinic/_asynciomodule.c.h
@@ -27,13 +27,22 @@ _asyncio_Future___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"loop", NULL};
-    static _PyArg_Parser _parser = {"|$O:Future", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "Future", 0};
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *loop = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &loop)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 0, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    loop = fastargs[0];
+skip_optional_kwonly:
     return_value = _asyncio_Future___init___impl((FutureObj *)self, loop);
 
 exit:
@@ -131,14 +140,22 @@ _asyncio_Future_add_done_callback(FutureObj *self, PyObject *const *args, Py_ssi
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "context", NULL};
-    static _PyArg_Parser _parser = {"O|$O:add_done_callback", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "add_done_callback", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *fn;
     PyObject *context = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &fn, &context)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    fn = args[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    context = args[1];
+skip_optional_kwonly:
     return_value = _asyncio_Future_add_done_callback_impl(self, fn, context);
 
 exit:
@@ -267,15 +284,31 @@ _asyncio_Task___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"coro", "loop", "name", NULL};
-    static _PyArg_Parser _parser = {"O|$OO:Task", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "Task", 0};
+    PyObject *argsbuf[3];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *coro;
     PyObject *loop = Py_None;
     PyObject *name = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &coro, &loop, &name)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    coro = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (fastargs[1]) {
+        loop = fastargs[1];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    name = fastargs[2];
+skip_optional_kwonly:
     return_value = _asyncio_Task___init___impl((TaskObj *)self, coro, loop, name);
 
 exit:
@@ -303,13 +336,20 @@ _asyncio_Task_current_task(PyTypeObject *type, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"loop", NULL};
-    static _PyArg_Parser _parser = {"|O:current_task", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "current_task", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *loop = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &loop)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    loop = args[0];
+skip_optional_pos:
     return_value = _asyncio_Task_current_task_impl(type, loop);
 
 exit:
@@ -335,13 +375,20 @@ _asyncio_Task_all_tasks(PyTypeObject *type, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"loop", NULL};
-    static _PyArg_Parser _parser = {"|O:all_tasks", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "all_tasks", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *loop = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &loop)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    loop = args[0];
+skip_optional_pos:
     return_value = _asyncio_Task_all_tasks_impl(type, loop);
 
 exit:
@@ -435,13 +482,20 @@ _asyncio_Task_get_stack(TaskObj *self, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"limit", NULL};
-    static _PyArg_Parser _parser = {"|$O:get_stack", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "get_stack", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *limit = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &limit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    limit = args[0];
+skip_optional_kwonly:
     return_value = _asyncio_Task_get_stack_impl(self, limit);
 
 exit:
@@ -472,14 +526,27 @@ _asyncio_Task_print_stack(TaskObj *self, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"limit", "file", NULL};
-    static _PyArg_Parser _parser = {"|$OO:print_stack", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "print_stack", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *limit = Py_None;
     PyObject *file = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &limit, &file)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[0]) {
+        limit = args[0];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    file = args[1];
+skip_optional_kwonly:
     return_value = _asyncio_Task_print_stack_impl(self, limit, file);
 
 exit:
@@ -624,13 +691,15 @@ _asyncio__register_task(PyObject *module, PyObject *const *args, Py_ssize_t narg
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"task", NULL};
-    static _PyArg_Parser _parser = {"O:_register_task", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_register_task", 0};
+    PyObject *argsbuf[1];
     PyObject *task;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &task)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    task = args[0];
     return_value = _asyncio__register_task_impl(module, task);
 
 exit:
@@ -656,13 +725,15 @@ _asyncio__unregister_task(PyObject *module, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"task", NULL};
-    static _PyArg_Parser _parser = {"O:_unregister_task", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_unregister_task", 0};
+    PyObject *argsbuf[1];
     PyObject *task;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &task)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    task = args[0];
     return_value = _asyncio__unregister_task_impl(module, task);
 
 exit:
@@ -690,14 +761,17 @@ _asyncio__enter_task(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"loop", "task", NULL};
-    static _PyArg_Parser _parser = {"OO:_enter_task", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_enter_task", 0};
+    PyObject *argsbuf[2];
     PyObject *loop;
     PyObject *task;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &loop, &task)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    loop = args[0];
+    task = args[1];
     return_value = _asyncio__enter_task_impl(module, loop, task);
 
 exit:
@@ -725,17 +799,20 @@ _asyncio__leave_task(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"loop", "task", NULL};
-    static _PyArg_Parser _parser = {"OO:_leave_task", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_leave_task", 0};
+    PyObject *argsbuf[2];
     PyObject *loop;
     PyObject *task;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &loop, &task)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    loop = args[0];
+    task = args[1];
     return_value = _asyncio__leave_task_impl(module, loop, task);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=fd474bdc8f03d5ae input=a9049054013a1b77]*/
+/*[clinic end generated code: output=e3b02d96da56e80c input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_bz2module.c.h b/Modules/clinic/_bz2module.c.h
index fb64333805..cc16d8bb22 100644
--- a/Modules/clinic/_bz2module.c.h
+++ b/Modules/clinic/_bz2module.c.h
@@ -142,14 +142,44 @@ _bz2_BZ2Decompressor_decompress(BZ2Decompressor *self, PyObject *const *args, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"data", "max_length", NULL};
-    static _PyArg_Parser _parser = {"y*|n:decompress", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decompress", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     Py_ssize_t max_length = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &max_length)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("decompress", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        max_length = ival;
+    }
+skip_optional_pos:
     return_value = _bz2_BZ2Decompressor_decompress_impl(self, &data, max_length);
 
 exit:
@@ -190,4 +220,4 @@ _bz2_BZ2Decompressor___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=892c6133e97ff840 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=8e123f4eec497655 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_codecsmodule.c.h b/Modules/clinic/_codecsmodule.c.h
index a8223ad0a1..d1f4cf3fc6 100644
--- a/Modules/clinic/_codecsmodule.c.h
+++ b/Modules/clinic/_codecsmodule.c.h
@@ -76,15 +76,53 @@ _codecs_encode(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"obj", "encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"O|ss:encode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "encode", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *obj;
     const char *encoding = NULL;
     const char *errors = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &obj, &encoding, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    obj = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (!PyUnicode_Check(args[1])) {
+            _PyArg_BadArgument("encode", 2, "str", args[1]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(args[1], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (!PyUnicode_Check(args[2])) {
+        _PyArg_BadArgument("encode", 3, "str", args[2]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(args[2], &errors_length);
+    if (errors == NULL) {
+        goto exit;
+    }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _codecs_encode_impl(module, obj, encoding, errors);
 
 exit:
@@ -115,15 +153,53 @@ _codecs_decode(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"obj", "encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"O|ss:decode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decode", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *obj;
     const char *encoding = NULL;
     const char *errors = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &obj, &encoding, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    obj = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (!PyUnicode_Check(args[1])) {
+            _PyArg_BadArgument("decode", 2, "str", args[1]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(args[1], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (!PyUnicode_Check(args[2])) {
+        _PyArg_BadArgument("decode", 3, "str", args[2]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(args[2], &errors_length);
+    if (errors == NULL) {
+        goto exit;
+    }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
+skip_optional_pos:
     return_value = _codecs_decode_impl(module, obj, encoding, errors);
 
 exit:
@@ -2948,4 +3024,4 @@ exit:
 #ifndef _CODECS_CODE_PAGE_ENCODE_METHODDEF
     #define _CODECS_CODE_PAGE_ENCODE_METHODDEF
 #endif /* !defined(_CODECS_CODE_PAGE_ENCODE_METHODDEF) */
-/*[clinic end generated code: output=85ea29db163ee74c input=a9049054013a1b77]*/
+/*[clinic end generated code: output=02bd0f0cf9a28150 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_cursesmodule.c.h b/Modules/clinic/_cursesmodule.c.h
index 659fd4ec4e..6837eac390 100644
--- a/Modules/clinic/_cursesmodule.c.h
+++ b/Modules/clinic/_cursesmodule.c.h
@@ -2988,14 +2988,52 @@ _curses_setupterm(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyO
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"term", "fd", NULL};
-    static _PyArg_Parser _parser = {"|zi:setupterm", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "setupterm", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     const char *term = NULL;
     int fd = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &term, &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (args[0] == Py_None) {
+            term = NULL;
+        }
+        else if (PyUnicode_Check(args[0])) {
+            Py_ssize_t term_length;
+            term = PyUnicode_AsUTF8AndSize(args[0], &term_length);
+            if (term == NULL) {
+                goto exit;
+            }
+            if (strlen(term) != (size_t)term_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("setupterm", 1, "str or None", args[0]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    fd = _PyLong_AsInt(args[1]);
+    if (fd == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _curses_setupterm_impl(module, term, fd);
 
 exit:
@@ -4531,4 +4569,4 @@ _curses_use_default_colors(PyObject *module, PyObject *Py_UNUSED(ignored))
 #ifndef _CURSES_USE_DEFAULT_COLORS_METHODDEF
     #define _CURSES_USE_DEFAULT_COLORS_METHODDEF
 #endif /* !defined(_CURSES_USE_DEFAULT_COLORS_METHODDEF) */
-/*[clinic end generated code: output=5305982cb312a911 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=1350eeb0c1e06af6 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_datetimemodule.c.h b/Modules/clinic/_datetimemodule.c.h
index 36b4fcac47..447036ca03 100644
--- a/Modules/clinic/_datetimemodule.c.h
+++ b/Modules/clinic/_datetimemodule.c.h
@@ -36,16 +36,23 @@ datetime_datetime_now(PyTypeObject *type, PyObject *const *args, Py_ssize_t narg
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"tz", NULL};
-    static _PyArg_Parser _parser = {"|O:now", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "now", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *tz = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &tz)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    tz = args[0];
+skip_optional_pos:
     return_value = datetime_datetime_now_impl(type, tz);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=b3d746843403a8ce input=a9049054013a1b77]*/
+/*[clinic end generated code: output=aae916ab728ca85b input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_elementtree.c.h b/Modules/clinic/_elementtree.c.h
index 1293acddc1..d239c80258 100644
--- a/Modules/clinic/_elementtree.c.h
+++ b/Modules/clinic/_elementtree.c.h
@@ -169,14 +169,22 @@ _elementtree_Element_find(ElementObject *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "namespaces", NULL};
-    static _PyArg_Parser _parser = {"O|O:find", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "find", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *path;
     PyObject *namespaces = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &path, &namespaces)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    path = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    namespaces = args[1];
+skip_optional_pos:
     return_value = _elementtree_Element_find_impl(self, path, namespaces);
 
 exit:
@@ -201,15 +209,29 @@ _elementtree_Element_findtext(ElementObject *self, PyObject *const *args, Py_ssi
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "default", "namespaces", NULL};
-    static _PyArg_Parser _parser = {"O|OO:findtext", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "findtext", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *path;
     PyObject *default_value = Py_None;
     PyObject *namespaces = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &path, &default_value, &namespaces)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    path = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        default_value = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    namespaces = args[2];
+skip_optional_pos:
     return_value = _elementtree_Element_findtext_impl(self, path, default_value, namespaces);
 
 exit:
@@ -233,14 +255,22 @@ _elementtree_Element_findall(ElementObject *self, PyObject *const *args, Py_ssiz
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "namespaces", NULL};
-    static _PyArg_Parser _parser = {"O|O:findall", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "findall", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *path;
     PyObject *namespaces = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &path, &namespaces)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    path = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    namespaces = args[1];
+skip_optional_pos:
     return_value = _elementtree_Element_findall_impl(self, path, namespaces);
 
 exit:
@@ -264,14 +294,22 @@ _elementtree_Element_iterfind(ElementObject *self, PyObject *const *args, Py_ssi
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "namespaces", NULL};
-    static _PyArg_Parser _parser = {"O|O:iterfind", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "iterfind", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *path;
     PyObject *namespaces = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &path, &namespaces)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    path = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    namespaces = args[1];
+skip_optional_pos:
     return_value = _elementtree_Element_iterfind_impl(self, path, namespaces);
 
 exit:
@@ -295,14 +333,22 @@ _elementtree_Element_get(ElementObject *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"key", "default", NULL};
-    static _PyArg_Parser _parser = {"O|O:get", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "get", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *key;
     PyObject *default_value = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &key, &default_value)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    key = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    default_value = args[1];
+skip_optional_pos:
     return_value = _elementtree_Element_get_impl(self, key, default_value);
 
 exit:
@@ -342,13 +388,20 @@ _elementtree_Element_iter(ElementObject *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"tag", NULL};
-    static _PyArg_Parser _parser = {"|O:iter", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "iter", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *tag = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &tag)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    tag = args[0];
+skip_optional_pos:
     return_value = _elementtree_Element_iter_impl(self, tag);
 
 exit:
@@ -371,13 +424,20 @@ _elementtree_Element_getiterator(ElementObject *self, PyObject *const *args, Py_
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"tag", NULL};
-    static _PyArg_Parser _parser = {"|O:getiterator", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "getiterator", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *tag = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &tag)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    tag = args[0];
+skip_optional_pos:
     return_value = _elementtree_Element_getiterator_impl(self, tag);
 
 exit:
@@ -582,13 +642,22 @@ _elementtree_TreeBuilder___init__(PyObject *self, PyObject *args, PyObject *kwar
 {
     int return_value = -1;
     static const char * const _keywords[] = {"element_factory", NULL};
-    static _PyArg_Parser _parser = {"|O:TreeBuilder", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "TreeBuilder", 0};
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *element_factory = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &element_factory)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    element_factory = fastargs[0];
+skip_optional_pos:
     return_value = _elementtree_TreeBuilder___init___impl((TreeBuilderObject *)self, element_factory);
 
 exit:
@@ -671,14 +740,46 @@ _elementtree_XMLParser___init__(PyObject *self, PyObject *args, PyObject *kwargs
 {
     int return_value = -1;
     static const char * const _keywords[] = {"target", "encoding", NULL};
-    static _PyArg_Parser _parser = {"|$Oz:XMLParser", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "XMLParser", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *target = NULL;
     const char *encoding = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &target, &encoding)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 0, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (fastargs[0]) {
+        target = fastargs[0];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[1] == Py_None) {
+        encoding = NULL;
+    }
+    else if (PyUnicode_Check(fastargs[1])) {
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(fastargs[1], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+    }
+    else {
+        _PyArg_BadArgument("XMLParser", 2, "str or None", fastargs[1]);
         goto exit;
     }
+skip_optional_kwonly:
     return_value = _elementtree_XMLParser___init___impl((XMLParserObject *)self, target, encoding);
 
 exit:
@@ -752,4 +853,4 @@ skip_optional:
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=0c15c41e03a7829f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=440b5d90a4b86590 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_hashopenssl.c.h b/Modules/clinic/_hashopenssl.c.h
index 43f9651245..5596f13e50 100644
--- a/Modules/clinic/_hashopenssl.c.h
+++ b/Modules/clinic/_hashopenssl.c.h
@@ -87,14 +87,22 @@ EVP_new(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwn
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"name", "string", NULL};
-    static _PyArg_Parser _parser = {"O|O:new", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "new", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *name_obj;
     PyObject *data_obj = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &name_obj, &data_obj)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    name_obj = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    data_obj = args[1];
+skip_optional_pos:
     return_value = EVP_new_impl(module, name_obj, data_obj);
 
 exit:
@@ -123,17 +131,60 @@ pbkdf2_hmac(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"hash_name", "password", "salt", "iterations", "dklen", NULL};
-    static _PyArg_Parser _parser = {"sy*y*l|O:pbkdf2_hmac", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "pbkdf2_hmac", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 4;
     const char *hash_name;
     Py_buffer password = {NULL, NULL};
     Py_buffer salt = {NULL, NULL};
     long iterations;
     PyObject *dklen_obj = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &hash_name, &password, &salt, &iterations, &dklen_obj)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 4, 5, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("pbkdf2_hmac", 1, "str", args[0]);
+        goto exit;
+    }
+    Py_ssize_t hash_name_length;
+    hash_name = PyUnicode_AsUTF8AndSize(args[0], &hash_name_length);
+    if (hash_name == NULL) {
+        goto exit;
+    }
+    if (strlen(hash_name) != (size_t)hash_name_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[1], &password, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&password, 'C')) {
+        _PyArg_BadArgument("pbkdf2_hmac", 2, "contiguous buffer", args[1]);
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[2], &salt, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&salt, 'C')) {
+        _PyArg_BadArgument("pbkdf2_hmac", 3, "contiguous buffer", args[2]);
+        goto exit;
+    }
+    if (PyFloat_Check(args[3])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    iterations = PyLong_AsLong(args[3]);
+    if (iterations == -1 && PyErr_Occurred()) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    dklen_obj = args[4];
+skip_optional_pos:
     return_value = pbkdf2_hmac_impl(module, hash_name, &password, &salt, iterations, dklen_obj);
 
 exit:
@@ -173,7 +224,9 @@ _hashlib_scrypt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"password", "salt", "n", "r", "p", "maxmem", "dklen", NULL};
-    static _PyArg_Parser _parser = {"y*|$y*O!O!O!ll:scrypt", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "scrypt", 0};
+    PyObject *argsbuf[7];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer password = {NULL, NULL};
     Py_buffer salt = {NULL, NULL};
     PyObject *n_obj = Py_None;
@@ -182,10 +235,86 @@ _hashlib_scrypt(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
     long maxmem = 0;
     long dklen = 64;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &password, &salt, &PyLong_Type, &n_obj, &PyLong_Type, &r_obj, &PyLong_Type, &p_obj, &maxmem, &dklen)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[0], &password, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&password, 'C')) {
+        _PyArg_BadArgument("scrypt", 1, "contiguous buffer", args[0]);
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[1]) {
+        if (PyObject_GetBuffer(args[1], &salt, PyBUF_SIMPLE) != 0) {
+            goto exit;
+        }
+        if (!PyBuffer_IsContiguous(&salt, 'C')) {
+            _PyArg_BadArgument("scrypt", 2, "contiguous buffer", args[1]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[2]) {
+        if (!PyLong_Check(args[2])) {
+            _PyArg_BadArgument("scrypt", 3, "int", args[2]);
+            goto exit;
+        }
+        n_obj = args[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[3]) {
+        if (!PyLong_Check(args[3])) {
+            _PyArg_BadArgument("scrypt", 4, "int", args[3]);
+            goto exit;
+        }
+        r_obj = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[4]) {
+        if (!PyLong_Check(args[4])) {
+            _PyArg_BadArgument("scrypt", 5, "int", args[4]);
+            goto exit;
+        }
+        p_obj = args[4];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[5]) {
+        if (PyFloat_Check(args[5])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        maxmem = PyLong_AsLong(args[5]);
+        if (maxmem == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (PyFloat_Check(args[6])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    dklen = PyLong_AsLong(args[6]);
+    if (dklen == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = _hashlib_scrypt_impl(module, &password, &salt, n_obj, r_obj, p_obj, maxmem, dklen);
 
 exit:
@@ -221,13 +350,41 @@ _hashlib_hmac_digest(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"key", "msg", "digest", NULL};
-    static _PyArg_Parser _parser = {"y*y*s:hmac_digest", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "hmac_digest", 0};
+    PyObject *argsbuf[3];
     Py_buffer key = {NULL, NULL};
     Py_buffer msg = {NULL, NULL};
     const char *digest;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &key, &msg, &digest)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[0], &key, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&key, 'C')) {
+        _PyArg_BadArgument("hmac_digest", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[1], &msg, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&msg, 'C')) {
+        _PyArg_BadArgument("hmac_digest", 2, "contiguous buffer", args[1]);
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[2])) {
+        _PyArg_BadArgument("hmac_digest", 3, "str", args[2]);
+        goto exit;
+    }
+    Py_ssize_t digest_length;
+    digest = PyUnicode_AsUTF8AndSize(args[2], &digest_length);
+    if (digest == NULL) {
+        goto exit;
+    }
+    if (strlen(digest) != (size_t)digest_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
     return_value = _hashlib_hmac_digest_impl(module, &key, &msg, digest);
@@ -252,4 +409,4 @@ exit:
 #ifndef _HASHLIB_SCRYPT_METHODDEF
     #define _HASHLIB_SCRYPT_METHODDEF
 #endif /* !defined(_HASHLIB_SCRYPT_METHODDEF) */
-/*[clinic end generated code: output=fe5931d2b301ca12 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=5955ec791260045a input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_lzmamodule.c.h b/Modules/clinic/_lzmamodule.c.h
index aeb98a6603..68aa770d41 100644
--- a/Modules/clinic/_lzmamodule.c.h
+++ b/Modules/clinic/_lzmamodule.c.h
@@ -96,14 +96,44 @@ _lzma_LZMADecompressor_decompress(Decompressor *self, PyObject *const *args, Py_
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"data", "max_length", NULL};
-    static _PyArg_Parser _parser = {"y*|n:decompress", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decompress", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     Py_ssize_t max_length = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &max_length)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("decompress", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        max_length = ival;
+    }
+skip_optional_pos:
     return_value = _lzma_LZMADecompressor_decompress_impl(self, &data, max_length);
 
 exit:
@@ -147,15 +177,44 @@ _lzma_LZMADecompressor___init__(PyObject *self, PyObject *args, PyObject *kwargs
 {
     int return_value = -1;
     static const char * const _keywords[] = {"format", "memlimit", "filters", NULL};
-    static _PyArg_Parser _parser = {"|iOO:LZMADecompressor", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "LZMADecompressor", 0};
+    PyObject *argsbuf[3];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     int format = FORMAT_AUTO;
     PyObject *memlimit = Py_None;
     PyObject *filters = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &format, &memlimit, &filters)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 3, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[0]) {
+        if (PyFloat_Check(fastargs[0])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        format = _PyLong_AsInt(fastargs[0]);
+        if (format == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[1]) {
+        memlimit = fastargs[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    filters = fastargs[2];
+skip_optional_pos:
     return_value = _lzma_LZMADecompressor___init___impl((Decompressor *)self, format, memlimit, filters);
 
 exit:
@@ -275,4 +334,4 @@ exit:
 
     return return_value;
 }
-/*[clinic end generated code: output=47e4732df79509ad input=a9049054013a1b77]*/
+/*[clinic end generated code: output=1a290aa478603107 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_opcode.c.h b/Modules/clinic/_opcode.c.h
index 2104a52915..777701ff14 100644
--- a/Modules/clinic/_opcode.c.h
+++ b/Modules/clinic/_opcode.c.h
@@ -20,16 +20,38 @@ _opcode_stack_effect(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "", "jump", NULL};
-    static _PyArg_Parser _parser = {"i|O$O:stack_effect", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "stack_effect", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     int opcode;
     PyObject *oparg = Py_None;
     PyObject *jump = Py_None;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &opcode, &oparg, &jump)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    opcode = _PyLong_AsInt(args[0]);
+    if (opcode == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (nargs < 2) {
+        goto skip_optional_posonly;
+    }
+    noptargs--;
+    oparg = args[1];
+skip_optional_posonly:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    jump = args[2];
+skip_optional_kwonly:
     _return_value = _opcode_stack_effect_impl(module, opcode, oparg, jump);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -39,4 +61,4 @@ _opcode_stack_effect(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=871941eea3d855c6 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=7bc08f2835b2cf89 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_pickle.c.h b/Modules/clinic/_pickle.c.h
index 2759b2f21e..1da2f936be 100644
--- a/Modules/clinic/_pickle.c.h
+++ b/Modules/clinic/_pickle.c.h
@@ -94,15 +94,34 @@ _pickle_Pickler___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"file", "protocol", "fix_imports", NULL};
-    static _PyArg_Parser _parser = {"O|Op:Pickler", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "Pickler", 0};
+    PyObject *argsbuf[3];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *file;
     PyObject *protocol = NULL;
     int fix_imports = 1;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &file, &protocol, &fix_imports)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 3, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    file = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[1]) {
+        protocol = fastargs[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    fix_imports = PyObject_IsTrue(fastargs[2]);
+    if (fix_imports < 0) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _pickle_Pickler___init___impl((PicklerObject *)self, file, protocol, fix_imports);
 
 exit:
@@ -287,16 +306,65 @@ _pickle_Unpickler___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"file", "fix_imports", "encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"O|$pss:Unpickler", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "Unpickler", 0};
+    PyObject *argsbuf[4];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *file;
     int fix_imports = 1;
     const char *encoding = "ASCII";
     const char *errors = "strict";
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &file, &fix_imports, &encoding, &errors)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    file = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (fastargs[1]) {
+        fix_imports = PyObject_IsTrue(fastargs[1]);
+        if (fix_imports < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[2]) {
+        if (!PyUnicode_Check(fastargs[2])) {
+            _PyArg_BadArgument("Unpickler", 3, "str", fastargs[2]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(fastargs[2], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (!PyUnicode_Check(fastargs[3])) {
+        _PyArg_BadArgument("Unpickler", 4, "str", fastargs[3]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(fastargs[3], &errors_length);
+    if (errors == NULL) {
         goto exit;
     }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = _pickle_Unpickler___init___impl((UnpicklerObject *)self, file, fix_imports, encoding, errors);
 
 exit:
@@ -396,16 +464,38 @@ _pickle_dump(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"obj", "file", "protocol", "fix_imports", NULL};
-    static _PyArg_Parser _parser = {"OO|O$p:dump", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "dump", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     PyObject *obj;
     PyObject *file;
     PyObject *protocol = NULL;
     int fix_imports = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &obj, &file, &protocol, &fix_imports)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    obj = args[0];
+    file = args[1];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        protocol = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    fix_imports = PyObject_IsTrue(args[3]);
+    if (fix_imports < 0) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = _pickle_dump_impl(module, obj, file, protocol, fix_imports);
 
 exit:
@@ -443,15 +533,36 @@ _pickle_dumps(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"obj", "protocol", "fix_imports", NULL};
-    static _PyArg_Parser _parser = {"O|O$p:dumps", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "dumps", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *obj;
     PyObject *protocol = NULL;
     int fix_imports = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &obj, &protocol, &fix_imports)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    obj = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        protocol = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    fix_imports = PyObject_IsTrue(args[2]);
+    if (fix_imports < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = _pickle_dumps_impl(module, obj, protocol, fix_imports);
 
 exit:
@@ -499,16 +610,63 @@ _pickle_load(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"file", "fix_imports", "encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"O|$pss:load", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "load", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *file;
     int fix_imports = 1;
     const char *encoding = "ASCII";
     const char *errors = "strict";
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &file, &fix_imports, &encoding, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    file = args[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[1]) {
+        fix_imports = PyObject_IsTrue(args[1]);
+        if (fix_imports < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[2]) {
+        if (!PyUnicode_Check(args[2])) {
+            _PyArg_BadArgument("load", 3, "str", args[2]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(args[2], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (!PyUnicode_Check(args[3])) {
+        _PyArg_BadArgument("load", 4, "str", args[3]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(args[3], &errors_length);
+    if (errors == NULL) {
+        goto exit;
+    }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
+skip_optional_kwonly:
     return_value = _pickle_load_impl(module, file, fix_imports, encoding, errors);
 
 exit:
@@ -547,19 +705,66 @@ _pickle_loads(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"data", "fix_imports", "encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"O|$pss:loads", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "loads", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *data;
     int fix_imports = 1;
     const char *encoding = "ASCII";
     const char *errors = "strict";
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &fix_imports, &encoding, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    data = args[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[1]) {
+        fix_imports = PyObject_IsTrue(args[1]);
+        if (fix_imports < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[2]) {
+        if (!PyUnicode_Check(args[2])) {
+            _PyArg_BadArgument("loads", 3, "str", args[2]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(args[2], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (!PyUnicode_Check(args[3])) {
+        _PyArg_BadArgument("loads", 4, "str", args[3]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(args[3], &errors_length);
+    if (errors == NULL) {
+        goto exit;
+    }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
+skip_optional_kwonly:
     return_value = _pickle_loads_impl(module, data, fix_imports, encoding, errors);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=225f06abcf27ed2b input=a9049054013a1b77]*/
+/*[clinic end generated code: output=8f972562c8f71e2b input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_queuemodule.c.h b/Modules/clinic/_queuemodule.c.h
index a19fe78e3a..c25eacf08b 100644
--- a/Modules/clinic/_queuemodule.c.h
+++ b/Modules/clinic/_queuemodule.c.h
@@ -51,15 +51,32 @@ _queue_SimpleQueue_put(simplequeueobject *self, PyObject *const *args, Py_ssize_
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"item", "block", "timeout", NULL};
-    static _PyArg_Parser _parser = {"O|pO:put", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "put", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *item;
     int block = 1;
     PyObject *timeout = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &item, &block, &timeout)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    item = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        block = PyObject_IsTrue(args[1]);
+        if (block < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    timeout = args[2];
+skip_optional_pos:
     return_value = _queue_SimpleQueue_put_impl(self, item, block, timeout);
 
 exit:
@@ -86,13 +103,15 @@ _queue_SimpleQueue_put_nowait(simplequeueobject *self, PyObject *const *args, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"item", NULL};
-    static _PyArg_Parser _parser = {"O:put_nowait", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "put_nowait", 0};
+    PyObject *argsbuf[1];
     PyObject *item;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &item)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    item = args[0];
     return_value = _queue_SimpleQueue_put_nowait_impl(self, item);
 
 exit:
@@ -125,14 +144,30 @@ _queue_SimpleQueue_get(simplequeueobject *self, PyObject *const *args, Py_ssize_
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"block", "timeout", NULL};
-    static _PyArg_Parser _parser = {"|pO:get", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "get", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int block = 1;
     PyObject *timeout = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &block, &timeout)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        block = PyObject_IsTrue(args[0]);
+        if (block < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    timeout = args[1];
+skip_optional_pos:
     return_value = _queue_SimpleQueue_get_impl(self, block, timeout);
 
 exit:
@@ -215,4 +250,4 @@ _queue_SimpleQueue_qsize(simplequeueobject *self, PyObject *Py_UNUSED(ignored))
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=c12ce9050f153304 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b4717e2974cbc909 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_sre.c.h b/Modules/clinic/_sre.c.h
index e5bb32fbea..9c08dec454 100644
--- a/Modules/clinic/_sre.c.h
+++ b/Modules/clinic/_sre.c.h
@@ -195,15 +195,61 @@ _sre_SRE_Pattern_match(PatternObject *self, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", "pos", "endpos", NULL};
-    static _PyArg_Parser _parser = {"O|nn:match", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "match", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *string;
     Py_ssize_t pos = 0;
     Py_ssize_t endpos = PY_SSIZE_T_MAX;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string, &pos, &endpos)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    string = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        {
+            Py_ssize_t ival = -1;
+            PyObject *iobj = PyNumber_Index(args[1]);
+            if (iobj != NULL) {
+                ival = PyLong_AsSsize_t(iobj);
+                Py_DECREF(iobj);
+            }
+            if (ival == -1 && PyErr_Occurred()) {
+                goto exit;
+            }
+            pos = ival;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        endpos = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_match_impl(self, string, pos, endpos);
 
 exit:
@@ -228,15 +274,61 @@ _sre_SRE_Pattern_fullmatch(PatternObject *self, PyObject *const *args, Py_ssize_
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", "pos", "endpos", NULL};
-    static _PyArg_Parser _parser = {"O|nn:fullmatch", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fullmatch", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *string;
     Py_ssize_t pos = 0;
     Py_ssize_t endpos = PY_SSIZE_T_MAX;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string, &pos, &endpos)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    string = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        {
+            Py_ssize_t ival = -1;
+            PyObject *iobj = PyNumber_Index(args[1]);
+            if (iobj != NULL) {
+                ival = PyLong_AsSsize_t(iobj);
+                Py_DECREF(iobj);
+            }
+            if (ival == -1 && PyErr_Occurred()) {
+                goto exit;
+            }
+            pos = ival;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        endpos = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_fullmatch_impl(self, string, pos, endpos);
 
 exit:
@@ -263,15 +355,61 @@ _sre_SRE_Pattern_search(PatternObject *self, PyObject *const *args, Py_ssize_t n
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", "pos", "endpos", NULL};
-    static _PyArg_Parser _parser = {"O|nn:search", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "search", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *string;
     Py_ssize_t pos = 0;
     Py_ssize_t endpos = PY_SSIZE_T_MAX;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string, &pos, &endpos)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    string = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        {
+            Py_ssize_t ival = -1;
+            PyObject *iobj = PyNumber_Index(args[1]);
+            if (iobj != NULL) {
+                ival = PyLong_AsSsize_t(iobj);
+                Py_DECREF(iobj);
+            }
+            if (ival == -1 && PyErr_Occurred()) {
+                goto exit;
+            }
+            pos = ival;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        endpos = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_search_impl(self, string, pos, endpos);
 
 exit:
@@ -296,15 +434,61 @@ _sre_SRE_Pattern_findall(PatternObject *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", "pos", "endpos", NULL};
-    static _PyArg_Parser _parser = {"O|nn:findall", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "findall", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *string;
     Py_ssize_t pos = 0;
     Py_ssize_t endpos = PY_SSIZE_T_MAX;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string, &pos, &endpos)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    string = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        {
+            Py_ssize_t ival = -1;
+            PyObject *iobj = PyNumber_Index(args[1]);
+            if (iobj != NULL) {
+                ival = PyLong_AsSsize_t(iobj);
+                Py_DECREF(iobj);
+            }
+            if (ival == -1 && PyErr_Occurred()) {
+                goto exit;
+            }
+            pos = ival;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        endpos = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_findall_impl(self, string, pos, endpos);
 
 exit:
@@ -331,15 +515,61 @@ _sre_SRE_Pattern_finditer(PatternObject *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", "pos", "endpos", NULL};
-    static _PyArg_Parser _parser = {"O|nn:finditer", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "finditer", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *string;
     Py_ssize_t pos = 0;
     Py_ssize_t endpos = PY_SSIZE_T_MAX;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string, &pos, &endpos)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    string = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        {
+            Py_ssize_t ival = -1;
+            PyObject *iobj = PyNumber_Index(args[1]);
+            if (iobj != NULL) {
+                ival = PyLong_AsSsize_t(iobj);
+                Py_DECREF(iobj);
+            }
+            if (ival == -1 && PyErr_Occurred()) {
+                goto exit;
+            }
+            pos = ival;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        endpos = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_finditer_impl(self, string, pos, endpos);
 
 exit:
@@ -363,15 +593,61 @@ _sre_SRE_Pattern_scanner(PatternObject *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", "pos", "endpos", NULL};
-    static _PyArg_Parser _parser = {"O|nn:scanner", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "scanner", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *string;
     Py_ssize_t pos = 0;
     Py_ssize_t endpos = PY_SSIZE_T_MAX;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string, &pos, &endpos)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    string = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        {
+            Py_ssize_t ival = -1;
+            PyObject *iobj = PyNumber_Index(args[1]);
+            if (iobj != NULL) {
+                ival = PyLong_AsSsize_t(iobj);
+                Py_DECREF(iobj);
+            }
+            if (ival == -1 && PyErr_Occurred()) {
+                goto exit;
+            }
+            pos = ival;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        endpos = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_scanner_impl(self, string, pos, endpos);
 
 exit:
@@ -396,14 +672,38 @@ _sre_SRE_Pattern_split(PatternObject *self, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", "maxsplit", NULL};
-    static _PyArg_Parser _parser = {"O|n:split", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "split", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *string;
     Py_ssize_t maxsplit = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string, &maxsplit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    string = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        maxsplit = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_split_impl(self, string, maxsplit);
 
 exit:
@@ -428,15 +728,40 @@ _sre_SRE_Pattern_sub(PatternObject *self, PyObject *const *args, Py_ssize_t narg
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"repl", "string", "count", NULL};
-    static _PyArg_Parser _parser = {"OO|n:sub", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sub", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     PyObject *repl;
     PyObject *string;
     Py_ssize_t count = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &repl, &string, &count)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    repl = args[0];
+    string = args[1];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        count = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_sub_impl(self, repl, string, count);
 
 exit:
@@ -461,15 +786,40 @@ _sre_SRE_Pattern_subn(PatternObject *self, PyObject *const *args, Py_ssize_t nar
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"repl", "string", "count", NULL};
-    static _PyArg_Parser _parser = {"OO|n:subn", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "subn", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     PyObject *repl;
     PyObject *string;
     Py_ssize_t count = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &repl, &string, &count)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    repl = args[0];
+    string = args[1];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        count = ival;
+    }
+skip_optional_pos:
     return_value = _sre_SRE_Pattern_subn_impl(self, repl, string, count);
 
 exit:
@@ -520,7 +870,8 @@ _sre_compile(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"pattern", "flags", "code", "groups", "groupindex", "indexgroup", NULL};
-    static _PyArg_Parser _parser = {"OiO!nO!O!:compile", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "compile", 0};
+    PyObject *argsbuf[6];
     PyObject *pattern;
     int flags;
     PyObject *code;
@@ -528,10 +879,52 @@ _sre_compile(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
     PyObject *groupindex;
     PyObject *indexgroup;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &pattern, &flags, &PyList_Type, &code, &groups, &PyDict_Type, &groupindex, &PyTuple_Type, &indexgroup)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 6, 6, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    pattern = args[0];
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    flags = _PyLong_AsInt(args[1]);
+    if (flags == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!PyList_Check(args[2])) {
+        _PyArg_BadArgument("compile", 3, "list", args[2]);
+        goto exit;
+    }
+    code = args[2];
+    if (PyFloat_Check(args[3])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[3]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        groups = ival;
+    }
+    if (!PyDict_Check(args[4])) {
+        _PyArg_BadArgument("compile", 5, "dict", args[4]);
+        goto exit;
+    }
+    groupindex = args[4];
+    if (!PyTuple_Check(args[5])) {
+        _PyArg_BadArgument("compile", 6, "tuple", args[5]);
+        goto exit;
+    }
+    indexgroup = args[5];
     return_value = _sre_compile_impl(module, pattern, flags, code, groups, groupindex, indexgroup);
 
 exit:
@@ -555,13 +948,15 @@ _sre_SRE_Match_expand(MatchObject *self, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"template", NULL};
-    static _PyArg_Parser _parser = {"O:expand", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "expand", 0};
+    PyObject *argsbuf[1];
     PyObject *template;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &template)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    template = args[0];
     return_value = _sre_SRE_Match_expand_impl(self, template);
 
 exit:
@@ -588,13 +983,20 @@ _sre_SRE_Match_groups(MatchObject *self, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"default", NULL};
-    static _PyArg_Parser _parser = {"|O:groups", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "groups", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *default_value = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &default_value)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    default_value = args[0];
+skip_optional_pos:
     return_value = _sre_SRE_Match_groups_impl(self, default_value);
 
 exit:
@@ -621,13 +1023,20 @@ _sre_SRE_Match_groupdict(MatchObject *self, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"default", NULL};
-    static _PyArg_Parser _parser = {"|O:groupdict", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "groupdict", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *default_value = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &default_value)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    default_value = args[0];
+skip_optional_pos:
     return_value = _sre_SRE_Match_groupdict_impl(self, default_value);
 
 exit:
@@ -798,4 +1207,4 @@ _sre_SRE_Scanner_search(ScannerObject *self, PyObject *Py_UNUSED(ignored))
 {
     return _sre_SRE_Scanner_search_impl(self);
 }
-/*[clinic end generated code: output=8d19359d6a4a3a7e input=a9049054013a1b77]*/
+/*[clinic end generated code: output=67b702da5bdc9cac input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_ssl.c.h b/Modules/clinic/_ssl.c.h
index 3ec30c3c98..b1012f7aee 100644
--- a/Modules/clinic/_ssl.c.h
+++ b/Modules/clinic/_ssl.c.h
@@ -340,13 +340,32 @@ _ssl__SSLSocket_get_channel_binding(PySSLSocket *self, PyObject *const *args, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"cb_type", NULL};
-    static _PyArg_Parser _parser = {"|s:get_channel_binding", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "get_channel_binding", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     const char *cb_type = "tls-unique";
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &cb_type)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("get_channel_binding", 1, "str", args[0]);
+        goto exit;
+    }
+    Py_ssize_t cb_type_length;
+    cb_type = PyUnicode_AsUTF8AndSize(args[0], &cb_type_length);
+    if (cb_type == NULL) {
+        goto exit;
+    }
+    if (strlen(cb_type) != (size_t)cb_type_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _ssl__SSLSocket_get_channel_binding_impl(self, cb_type);
 
 exit:
@@ -548,15 +567,29 @@ _ssl__SSLContext_load_cert_chain(PySSLContext *self, PyObject *const *args, Py_s
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"certfile", "keyfile", "password", NULL};
-    static _PyArg_Parser _parser = {"O|OO:load_cert_chain", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "load_cert_chain", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *certfile;
     PyObject *keyfile = NULL;
     PyObject *password = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &certfile, &keyfile, &password)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    certfile = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        keyfile = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    password = args[2];
+skip_optional_pos:
     return_value = _ssl__SSLContext_load_cert_chain_impl(self, certfile, keyfile, password);
 
 exit:
@@ -582,15 +615,34 @@ _ssl__SSLContext_load_verify_locations(PySSLContext *self, PyObject *const *args
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"cafile", "capath", "cadata", NULL};
-    static _PyArg_Parser _parser = {"|OOO:load_verify_locations", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "load_verify_locations", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *cafile = NULL;
     PyObject *capath = NULL;
     PyObject *cadata = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &cafile, &capath, &cadata)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        cafile = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[1]) {
+        capath = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    cadata = args[2];
+skip_optional_pos:
     return_value = _ssl__SSLContext_load_verify_locations_impl(self, cafile, capath, cadata);
 
 exit:
@@ -624,17 +676,54 @@ _ssl__SSLContext__wrap_socket(PySSLContext *self, PyObject *const *args, Py_ssiz
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sock", "server_side", "server_hostname", "owner", "session", NULL};
-    static _PyArg_Parser _parser = {"O!i|O$OO:_wrap_socket", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_wrap_socket", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     PyObject *sock;
     int server_side;
     PyObject *hostname_obj = Py_None;
     PyObject *owner = Py_None;
     PyObject *session = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        PySocketModule.Sock_Type, &sock, &server_side, &hostname_obj, &owner, &session)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyObject_TypeCheck(args[0], PySocketModule.Sock_Type)) {
+        _PyArg_BadArgument("_wrap_socket", 1, (PySocketModule.Sock_Type)->tp_name, args[0]);
         goto exit;
     }
+    sock = args[0];
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    server_side = _PyLong_AsInt(args[1]);
+    if (server_side == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        hostname_obj = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[3]) {
+        owner = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    session = args[4];
+skip_optional_kwonly:
     return_value = _ssl__SSLContext__wrap_socket_impl(self, sock, server_side, hostname_obj, owner, session);
 
 exit:
@@ -661,7 +750,9 @@ _ssl__SSLContext__wrap_bio(PySSLContext *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"incoming", "outgoing", "server_side", "server_hostname", "owner", "session", NULL};
-    static _PyArg_Parser _parser = {"O!O!i|O$OO:_wrap_bio", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_wrap_bio", 0};
+    PyObject *argsbuf[6];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
     PySSLMemoryBIO *incoming;
     PySSLMemoryBIO *outgoing;
     int server_side;
@@ -669,10 +760,50 @@ _ssl__SSLContext__wrap_bio(PySSLContext *self, PyObject *const *args, Py_ssize_t
     PyObject *owner = Py_None;
     PyObject *session = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &PySSLMemoryBIO_Type, &incoming, &PySSLMemoryBIO_Type, &outgoing, &server_side, &hostname_obj, &owner, &session)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 4, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!PyObject_TypeCheck(args[0], &PySSLMemoryBIO_Type)) {
+        _PyArg_BadArgument("_wrap_bio", 1, (&PySSLMemoryBIO_Type)->tp_name, args[0]);
+        goto exit;
+    }
+    incoming = (PySSLMemoryBIO *)args[0];
+    if (!PyObject_TypeCheck(args[1], &PySSLMemoryBIO_Type)) {
+        _PyArg_BadArgument("_wrap_bio", 2, (&PySSLMemoryBIO_Type)->tp_name, args[1]);
+        goto exit;
+    }
+    outgoing = (PySSLMemoryBIO *)args[1];
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    server_side = _PyLong_AsInt(args[2]);
+    if (server_side == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[3]) {
+        hostname_obj = args[3];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[4]) {
+        owner = args[4];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    session = args[5];
+skip_optional_kwonly:
     return_value = _ssl__SSLContext__wrap_bio_impl(self, incoming, outgoing, server_side, hostname_obj, owner, session);
 
 exit:
@@ -772,13 +903,23 @@ _ssl__SSLContext_get_ca_certs(PySSLContext *self, PyObject *const *args, Py_ssiz
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"binary_form", NULL};
-    static _PyArg_Parser _parser = {"|p:get_ca_certs", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "get_ca_certs", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int binary_form = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &binary_form)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    binary_form = PyObject_IsTrue(args[0]);
+    if (binary_form < 0) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _ssl__SSLContext_get_ca_certs_impl(self, binary_form);
 
 exit:
@@ -1131,14 +1272,37 @@ _ssl_txt2obj(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"txt", "name", NULL};
-    static _PyArg_Parser _parser = {"s|p:txt2obj", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "txt2obj", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     const char *txt;
     int name = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &txt, &name)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("txt2obj", 1, "str", args[0]);
+        goto exit;
+    }
+    Py_ssize_t txt_length;
+    txt = PyUnicode_AsUTF8AndSize(args[0], &txt_length);
+    if (txt == NULL) {
+        goto exit;
+    }
+    if (strlen(txt) != (size_t)txt_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    name = PyObject_IsTrue(args[1]);
+    if (name < 0) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = _ssl_txt2obj_impl(module, txt, name);
 
 exit:
@@ -1203,11 +1367,25 @@ _ssl_enum_certificates(PyObject *module, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"store_name", NULL};
-    static _PyArg_Parser _parser = {"s:enum_certificates", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "enum_certificates", 0};
+    PyObject *argsbuf[1];
     const char *store_name;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &store_name)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("enum_certificates", 1, "str", args[0]);
+        goto exit;
+    }
+    Py_ssize_t store_name_length;
+    store_name = PyUnicode_AsUTF8AndSize(args[0], &store_name_length);
+    if (store_name == NULL) {
+        goto exit;
+    }
+    if (strlen(store_name) != (size_t)store_name_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
     return_value = _ssl_enum_certificates_impl(module, store_name);
@@ -1242,11 +1420,25 @@ _ssl_enum_crls(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"store_name", NULL};
-    static _PyArg_Parser _parser = {"s:enum_crls", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "enum_crls", 0};
+    PyObject *argsbuf[1];
     const char *store_name;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &store_name)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("enum_crls", 1, "str", args[0]);
+        goto exit;
+    }
+    Py_ssize_t store_name_length;
+    store_name = PyUnicode_AsUTF8AndSize(args[0], &store_name_length);
+    if (store_name == NULL) {
+        goto exit;
+    }
+    if (strlen(store_name) != (size_t)store_name_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
     return_value = _ssl_enum_crls_impl(module, store_name);
@@ -1284,4 +1476,4 @@ exit:
 #ifndef _SSL_ENUM_CRLS_METHODDEF
     #define _SSL_ENUM_CRLS_METHODDEF
 #endif /* !defined(_SSL_ENUM_CRLS_METHODDEF) */
-/*[clinic end generated code: output=ac3fb15ca27500f2 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=a399d0eb393b6fab input=a9049054013a1b77]*/
diff --git a/Modules/clinic/_struct.c.h b/Modules/clinic/_struct.c.h
index 2cc2d216f8..908c44266c 100644
--- a/Modules/clinic/_struct.c.h
+++ b/Modules/clinic/_struct.c.h
@@ -21,13 +21,17 @@ Struct___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"format", NULL};
-    static _PyArg_Parser _parser = {"O:Struct", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "Struct", 0};
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     PyObject *format;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &format)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    format = fastargs[0];
     return_value = Struct___init___impl((PyStructObject *)self, format);
 
 exit:
@@ -100,14 +104,44 @@ Struct_unpack_from(PyStructObject *self, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"buffer", "offset", NULL};
-    static _PyArg_Parser _parser = {"y*|n:unpack_from", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "unpack_from", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer buffer = {NULL, NULL};
     Py_ssize_t offset = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &buffer, &offset)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (PyObject_GetBuffer(args[0], &buffer, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&buffer, 'C')) {
+        _PyArg_BadArgument("unpack_from", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        offset = ival;
+    }
+skip_optional_pos:
     return_value = Struct_unpack_from_impl(self, &buffer, offset);
 
 exit:
@@ -257,15 +291,48 @@ unpack_from(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "buffer", "offset", NULL};
-    static _PyArg_Parser _parser = {"O&y*|n:unpack_from", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "unpack_from", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     PyStructObject *s_object = NULL;
     Py_buffer buffer = {NULL, NULL};
     Py_ssize_t offset = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        cache_struct_converter, &s_object, &buffer, &offset)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!cache_struct_converter(args[0], &s_object)) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[1], &buffer, PyBUF_SIMPLE) != 0) {
         goto exit;
     }
+    if (!PyBuffer_IsContiguous(&buffer, 'C')) {
+        _PyArg_BadArgument("unpack_from", 2, "contiguous buffer", args[1]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        offset = ival;
+    }
+skip_optional_pos:
     return_value = unpack_from_impl(module, s_object, &buffer, offset);
 
 exit:
@@ -319,4 +386,4 @@ exit:
 
     return return_value;
 }
-/*[clinic end generated code: output=ac595db9d2b271aa input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b642e1002d25ebdd input=a9049054013a1b77]*/
diff --git a/Modules/clinic/binascii.c.h b/Modules/clinic/binascii.c.h
index 3295833e87..4043d89d97 100644
--- a/Modules/clinic/binascii.c.h
+++ b/Modules/clinic/binascii.c.h
@@ -50,14 +50,36 @@ binascii_b2a_uu(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "backtick", NULL};
-    static _PyArg_Parser _parser = {"y*|$i:b2a_uu", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "b2a_uu", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     int backtick = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &backtick)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("b2a_uu", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    backtick = _PyLong_AsInt(args[1]);
+    if (backtick == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = binascii_b2a_uu_impl(module, &data, backtick);
 
 exit:
@@ -117,14 +139,36 @@ binascii_b2a_base64(PyObject *module, PyObject *const *args, Py_ssize_t nargs, P
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "newline", NULL};
-    static _PyArg_Parser _parser = {"y*|$i:b2a_base64", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "b2a_base64", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     int newline = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &newline)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("b2a_base64", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    newline = _PyLong_AsInt(args[1]);
+    if (newline == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = binascii_b2a_base64_impl(module, &data, newline);
 
 exit:
@@ -548,14 +592,32 @@ binascii_a2b_qp(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"data", "header", NULL};
-    static _PyArg_Parser _parser = {"O&|i:a2b_qp", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "a2b_qp", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     int header = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        ascii_buffer_converter, &data, &header)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!ascii_buffer_converter(args[0], &data)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    header = _PyLong_AsInt(args[1]);
+    if (header == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = binascii_a2b_qp_impl(module, &data, header);
 
 exit:
@@ -588,16 +650,66 @@ binascii_b2a_qp(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"data", "quotetabs", "istext", "header", NULL};
-    static _PyArg_Parser _parser = {"y*|iii:b2a_qp", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "b2a_qp", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     int quotetabs = 0;
     int istext = 1;
     int header = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &quotetabs, &istext, &header)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 4, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("b2a_qp", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        quotetabs = _PyLong_AsInt(args[1]);
+        if (quotetabs == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[2]) {
+        if (PyFloat_Check(args[2])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        istext = _PyLong_AsInt(args[2]);
+        if (istext == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[3])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    header = _PyLong_AsInt(args[3]);
+    if (header == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = binascii_b2a_qp_impl(module, &data, quotetabs, istext, header);
 
 exit:
@@ -608,4 +720,4 @@ exit:
 
     return return_value;
 }
-/*[clinic end generated code: output=7210a01a718da4a0 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=a4a38e162605aca2 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/cmathmodule.c.h b/Modules/clinic/cmathmodule.c.h
index cc1b8f2e21..83c498c224 100644
--- a/Modules/clinic/cmathmodule.c.h
+++ b/Modules/clinic/cmathmodule.c.h
@@ -897,17 +897,44 @@ cmath_isclose(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"a", "b", "rel_tol", "abs_tol", NULL};
-    static _PyArg_Parser _parser = {"DD|$dd:isclose", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "isclose", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     Py_complex a;
     Py_complex b;
     double rel_tol = 1e-09;
     double abs_tol = 0.0;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &a, &b, &rel_tol, &abs_tol)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    a = PyComplex_AsCComplex(args[0]);
+    if (PyErr_Occurred()) {
+        goto exit;
+    }
+    b = PyComplex_AsCComplex(args[1]);
+    if (PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        rel_tol = PyFloat_AsDouble(args[2]);
+        if (PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    abs_tol = PyFloat_AsDouble(args[3]);
+    if (PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_kwonly:
     _return_value = cmath_isclose_impl(module, a, b, rel_tol, abs_tol);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -917,4 +944,4 @@ cmath_isclose(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=86a365d23f34aaff input=a9049054013a1b77]*/
+/*[clinic end generated code: output=c7afb866e593fa45 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/gcmodule.c.h b/Modules/clinic/gcmodule.c.h
index eece04597b..22d2aa4a87 100644
--- a/Modules/clinic/gcmodule.c.h
+++ b/Modules/clinic/gcmodule.c.h
@@ -89,14 +89,29 @@ gc_collect(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"generation", NULL};
-    static _PyArg_Parser _parser = {"|i:collect", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "collect", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int generation = NUM_GENERATIONS - 1;
     Py_ssize_t _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &generation)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    generation = _PyLong_AsInt(args[0]);
+    if (generation == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     _return_value = gc_collect_impl(module, generation);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -238,13 +253,22 @@ gc_get_objects(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"generation", NULL};
-    static _PyArg_Parser _parser = {"|O&:get_objects", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "get_objects", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     Py_ssize_t generation = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        _Py_convert_optional_to_ssize_t, &generation)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (!_Py_convert_optional_to_ssize_t(args[0], &generation)) {
         goto exit;
     }
+skip_optional_pos:
     return_value = gc_get_objects_impl(module, generation);
 
 exit:
@@ -349,4 +373,4 @@ gc_get_freeze_count(PyObject *module, PyObject *Py_UNUSED(ignored))
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=d692bf475f0bb096 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=e40d384b1f0d513c input=a9049054013a1b77]*/
diff --git a/Modules/clinic/grpmodule.c.h b/Modules/clinic/grpmodule.c.h
index c2e54c94e0..ae99c50955 100644
--- a/Modules/clinic/grpmodule.c.h
+++ b/Modules/clinic/grpmodule.c.h
@@ -21,13 +21,15 @@ grp_getgrgid(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"id", NULL};
-    static _PyArg_Parser _parser = {"O:getgrgid", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "getgrgid", 0};
+    PyObject *argsbuf[1];
     PyObject *id;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &id)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    id = args[0];
     return_value = grp_getgrgid_impl(module, id);
 
 exit:
@@ -53,13 +55,22 @@ grp_getgrnam(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"name", NULL};
-    static _PyArg_Parser _parser = {"U:getgrnam", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "getgrnam", 0};
+    PyObject *argsbuf[1];
     PyObject *name;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &name)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("getgrnam", 1, "str", args[0]);
+        goto exit;
+    }
+    if (PyUnicode_READY(args[0]) == -1) {
+        goto exit;
+    }
+    name = args[0];
     return_value = grp_getgrnam_impl(module, name);
 
 exit:
@@ -86,4 +97,4 @@ grp_getgrall(PyObject *module, PyObject *Py_UNUSED(ignored))
 {
     return grp_getgrall_impl(module);
 }
-/*[clinic end generated code: output=ab10233f6015bc0a input=a9049054013a1b77]*/
+/*[clinic end generated code: output=2aa6c60873d41ee8 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/itertoolsmodule.c.h b/Modules/clinic/itertoolsmodule.c.h
index bcf4c5f979..b43ce64af0 100644
--- a/Modules/clinic/itertoolsmodule.c.h
+++ b/Modules/clinic/itertoolsmodule.c.h
@@ -23,14 +23,24 @@ itertools_groupby(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"iterable", "key", NULL};
-    static _PyArg_Parser _parser = {"O|O:groupby", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "groupby", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *it;
     PyObject *keyfunc = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &it, &keyfunc)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    it = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    keyfunc = fastargs[1];
+skip_optional_pos:
     return_value = itertools_groupby_impl(type, it, keyfunc);
 
 exit:
@@ -334,14 +344,35 @@ itertools_combinations(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"iterable", "r", NULL};
-    static _PyArg_Parser _parser = {"On:combinations", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "combinations", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     PyObject *iterable;
     Py_ssize_t r;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &iterable, &r)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 2, 2, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    iterable = fastargs[0];
+    if (PyFloat_Check(fastargs[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(fastargs[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        r = ival;
+    }
     return_value = itertools_combinations_impl(type, iterable, r);
 
 exit:
@@ -366,14 +397,35 @@ itertools_combinations_with_replacement(PyTypeObject *type, PyObject *args, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"iterable", "r", NULL};
-    static _PyArg_Parser _parser = {"On:combinations_with_replacement", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "combinations_with_replacement", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     PyObject *iterable;
     Py_ssize_t r;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &iterable, &r)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 2, 2, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    iterable = fastargs[0];
+    if (PyFloat_Check(fastargs[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(fastargs[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        r = ival;
+    }
     return_value = itertools_combinations_with_replacement_impl(type, iterable, r);
 
 exit:
@@ -397,14 +449,24 @@ itertools_permutations(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"iterable", "r", NULL};
-    static _PyArg_Parser _parser = {"O|O:permutations", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "permutations", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *iterable;
     PyObject *robj = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &iterable, &robj)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    iterable = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    robj = fastargs[1];
+skip_optional_pos:
     return_value = itertools_permutations_impl(type, iterable, robj);
 
 exit:
@@ -426,15 +488,35 @@ itertools_accumulate(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"iterable", "func", "initial", NULL};
-    static _PyArg_Parser _parser = {"O|O$O:accumulate", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "accumulate", 0};
+    PyObject *argsbuf[3];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *iterable;
     PyObject *binop = Py_None;
     PyObject *initial = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &iterable, &binop, &initial)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    iterable = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[1]) {
+        binop = fastargs[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    initial = fastargs[2];
+skip_optional_kwonly:
     return_value = itertools_accumulate_impl(type, iterable, binop, initial);
 
 exit:
@@ -458,14 +540,19 @@ itertools_compress(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"data", "selectors", NULL};
-    static _PyArg_Parser _parser = {"OO:compress", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "compress", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     PyObject *seq1;
     PyObject *seq2;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &seq1, &seq2)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 2, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    seq1 = fastargs[0];
+    seq2 = fastargs[1];
     return_value = itertools_compress_impl(type, seq1, seq2);
 
 exit:
@@ -527,17 +614,32 @@ itertools_count(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"start", "step", NULL};
-    static _PyArg_Parser _parser = {"|OO:count", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "count", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *long_cnt = NULL;
     PyObject *long_step = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &long_cnt, &long_step)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[0]) {
+        long_cnt = fastargs[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    long_step = fastargs[1];
+skip_optional_pos:
     return_value = itertools_count_impl(type, long_cnt, long_step);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=3d0ca69707b60715 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=04c49debcae96003 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/mathmodule.c.h b/Modules/clinic/mathmodule.c.h
index b99a8deece..1806a01588 100644
--- a/Modules/clinic/mathmodule.c.h
+++ b/Modules/clinic/mathmodule.c.h
@@ -536,17 +536,44 @@ math_isclose(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"a", "b", "rel_tol", "abs_tol", NULL};
-    static _PyArg_Parser _parser = {"dd|$dd:isclose", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "isclose", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     double a;
     double b;
     double rel_tol = 1e-09;
     double abs_tol = 0.0;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &a, &b, &rel_tol, &abs_tol)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    a = PyFloat_AsDouble(args[0]);
+    if (PyErr_Occurred()) {
+        goto exit;
+    }
+    b = PyFloat_AsDouble(args[1]);
+    if (PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        rel_tol = PyFloat_AsDouble(args[2]);
+        if (PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    abs_tol = PyFloat_AsDouble(args[3]);
+    if (PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_kwonly:
     _return_value = math_isclose_impl(module, a, b, rel_tol, abs_tol);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -580,17 +607,25 @@ math_prod(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "start", NULL};
-    static _PyArg_Parser _parser = {"O|$O:prod", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "prod", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *iterable;
     PyObject *start = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &iterable, &start)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    iterable = args[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    start = args[1];
+skip_optional_kwonly:
     return_value = math_prod_impl(module, iterable, start);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=20505690ca6fe402 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=96e71135dce41c48 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/md5module.c.h b/Modules/clinic/md5module.c.h
index 67cb48c084..12484cc0e3 100644
--- a/Modules/clinic/md5module.c.h
+++ b/Modules/clinic/md5module.c.h
@@ -82,16 +82,23 @@ _md5_md5(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", NULL};
-    static _PyArg_Parser _parser = {"|O:md5", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "md5", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *string = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    string = args[0];
+skip_optional_pos:
     return_value = _md5_md5_impl(module, string);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=83cb1aef575f13bc input=a9049054013a1b77]*/
+/*[clinic end generated code: output=53133f08cf9095fc input=a9049054013a1b77]*/
diff --git a/Modules/clinic/posixmodule.c.h b/Modules/clinic/posixmodule.c.h
index dc5f3b14ab..55f2cbb91a 100644
--- a/Modules/clinic/posixmodule.c.h
+++ b/Modules/clinic/posixmodule.c.h
@@ -38,15 +38,36 @@ os_stat(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwn
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "dir_fd", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&|$O&p:stat", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "stat", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("stat", "path", 0, 1);
     int dir_fd = DEFAULT_DIR_FD;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, FSTATAT_DIR_FD_CONVERTER, &dir_fd, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[1]) {
+        if (!FSTATAT_DIR_FD_CONVERTER(args[1], &dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    follow_symlinks = PyObject_IsTrue(args[2]);
+    if (follow_symlinks < 0) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_stat_impl(module, &path, dir_fd, follow_symlinks);
 
 exit:
@@ -76,14 +97,26 @@ os_lstat(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|$O&:lstat", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "lstat", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("lstat", "path", 0, 0);
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, FSTATAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!FSTATAT_DIR_FD_CONVERTER(args[1], &dir_fd)) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_lstat_impl(module, &path, dir_fd);
 
 exit:
@@ -137,7 +170,9 @@ os_access(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "mode", "dir_fd", "effective_ids", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&i|$O&pp:access", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "access", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t path = PATH_T_INITIALIZE("access", "path", 0, 0);
     int mode;
     int dir_fd = DEFAULT_DIR_FD;
@@ -145,10 +180,47 @@ os_access(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
     int follow_symlinks = 1;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &mode, FACCESSAT_DIR_FD_CONVERTER, &dir_fd, &effective_ids, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    mode = _PyLong_AsInt(args[1]);
+    if (mode == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        if (!FACCESSAT_DIR_FD_CONVERTER(args[2], &dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[3]) {
+        effective_ids = PyObject_IsTrue(args[3]);
+        if (effective_ids < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    follow_symlinks = PyObject_IsTrue(args[4]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     _return_value = os_access_impl(module, &path, mode, dir_fd, effective_ids, follow_symlinks);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -245,11 +317,15 @@ os_chdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"O&:chdir", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "chdir", 0};
+    PyObject *argsbuf[1];
     path_t path = PATH_T_INITIALIZE("chdir", "path", 0, PATH_HAVE_FCHDIR);
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
     return_value = os_chdir_impl(module, &path);
@@ -283,11 +359,15 @@ os_fchdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", NULL};
-    static _PyArg_Parser _parser = {"O&:fchdir", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fchdir", 0};
+    PyObject *argsbuf[1];
     int fd;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        fildes_converter, &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!fildes_converter(args[0], &fd)) {
         goto exit;
     }
     return_value = os_fchdir_impl(module, fd);
@@ -336,16 +416,46 @@ os_chmod(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "mode", "dir_fd", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&i|$O&p:chmod", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "chmod", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t path = PATH_T_INITIALIZE("chmod", "path", 0, PATH_HAVE_FCHMOD);
     int mode;
     int dir_fd = DEFAULT_DIR_FD;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &mode, FCHMODAT_DIR_FD_CONVERTER, &dir_fd, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    mode = _PyLong_AsInt(args[1]);
+    if (mode == -1 && PyErr_Occurred()) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        if (!FCHMODAT_DIR_FD_CONVERTER(args[2], &dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    follow_symlinks = PyObject_IsTrue(args[3]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_chmod_impl(module, &path, mode, dir_fd, follow_symlinks);
 
 exit:
@@ -376,12 +486,31 @@ os_fchmod(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", "mode", NULL};
-    static _PyArg_Parser _parser = {"ii:fchmod", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fchmod", 0};
+    PyObject *argsbuf[2];
     int fd;
     int mode;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &fd, &mode)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    fd = _PyLong_AsInt(args[0]);
+    if (fd == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    mode = _PyLong_AsInt(args[1]);
+    if (mode == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_fchmod_impl(module, fd, mode);
@@ -414,12 +543,25 @@ os_lchmod(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "mode", NULL};
-    static _PyArg_Parser _parser = {"O&i:lchmod", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "lchmod", 0};
+    PyObject *argsbuf[2];
     path_t path = PATH_T_INITIALIZE("lchmod", "path", 0, 0);
     int mode;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &mode)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    mode = _PyLong_AsInt(args[1]);
+    if (mode == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_lchmod_impl(module, &path, mode);
@@ -459,15 +601,33 @@ os_chflags(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "flags", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&k|p:chflags", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "chflags", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t path = PATH_T_INITIALIZE("chflags", "path", 0, 0);
     unsigned long flags;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &flags, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!PyLong_Check(args[1])) {
+        _PyArg_BadArgument("chflags", 2, "int", args[1]);
+        goto exit;
+    }
+    flags = PyLong_AsUnsignedLongMask(args[1]);
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    follow_symlinks = PyObject_IsTrue(args[2]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = os_chflags_impl(module, &path, flags, follow_symlinks);
 
 exit:
@@ -501,14 +661,23 @@ os_lchflags(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "flags", NULL};
-    static _PyArg_Parser _parser = {"O&k:lchflags", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "lchflags", 0};
+    PyObject *argsbuf[2];
     path_t path = PATH_T_INITIALIZE("lchflags", "path", 0, 0);
     unsigned long flags;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &flags)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!PyLong_Check(args[1])) {
+        _PyArg_BadArgument("lchflags", 2, "int", args[1]);
         goto exit;
     }
+    flags = PyLong_AsUnsignedLongMask(args[1]);
     return_value = os_lchflags_impl(module, &path, flags);
 
 exit:
@@ -539,11 +708,15 @@ os_chroot(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"O&:chroot", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "chroot", 0};
+    PyObject *argsbuf[1];
     path_t path = PATH_T_INITIALIZE("chroot", "path", 0, 0);
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
     return_value = os_chroot_impl(module, &path);
@@ -576,11 +749,15 @@ os_fsync(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", NULL};
-    static _PyArg_Parser _parser = {"O&:fsync", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fsync", 0};
+    PyObject *argsbuf[1];
     int fd;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        fildes_converter, &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!fildes_converter(args[0], &fd)) {
         goto exit;
     }
     return_value = os_fsync_impl(module, fd);
@@ -632,11 +809,15 @@ os_fdatasync(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", NULL};
-    static _PyArg_Parser _parser = {"O&:fdatasync", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fdatasync", 0};
+    PyObject *argsbuf[1];
     int fd;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        fildes_converter, &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!fildes_converter(args[0], &fd)) {
         goto exit;
     }
     return_value = os_fdatasync_impl(module, fd);
@@ -691,17 +872,44 @@ os_chown(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "uid", "gid", "dir_fd", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&O&O&|$O&p:chown", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "chown", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
     path_t path = PATH_T_INITIALIZE("chown", "path", 0, PATH_HAVE_FCHOWN);
     uid_t uid;
     gid_t gid;
     int dir_fd = DEFAULT_DIR_FD;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, _Py_Uid_Converter, &uid, _Py_Gid_Converter, &gid, FCHOWNAT_DIR_FD_CONVERTER, &dir_fd, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    if (!_Py_Uid_Converter(args[1], &uid)) {
+        goto exit;
+    }
+    if (!_Py_Gid_Converter(args[2], &gid)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[3]) {
+        if (!FCHOWNAT_DIR_FD_CONVERTER(args[3], &dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    follow_symlinks = PyObject_IsTrue(args[4]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_chown_impl(module, &path, uid, gid, dir_fd, follow_symlinks);
 
 exit:
@@ -734,13 +942,29 @@ os_fchown(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", "uid", "gid", NULL};
-    static _PyArg_Parser _parser = {"iO&O&:fchown", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fchown", 0};
+    PyObject *argsbuf[3];
     int fd;
     uid_t uid;
     gid_t gid;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &fd, _Py_Uid_Converter, &uid, _Py_Gid_Converter, &gid)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    fd = _PyLong_AsInt(args[0]);
+    if (fd == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!_Py_Uid_Converter(args[1], &uid)) {
+        goto exit;
+    }
+    if (!_Py_Gid_Converter(args[2], &gid)) {
         goto exit;
     }
     return_value = os_fchown_impl(module, fd, uid, gid);
@@ -773,13 +997,23 @@ os_lchown(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "uid", "gid", NULL};
-    static _PyArg_Parser _parser = {"O&O&O&:lchown", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "lchown", 0};
+    PyObject *argsbuf[3];
     path_t path = PATH_T_INITIALIZE("lchown", "path", 0, 0);
     uid_t uid;
     gid_t gid;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, _Py_Uid_Converter, &uid, _Py_Gid_Converter, &gid)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!_Py_Uid_Converter(args[1], &uid)) {
+        goto exit;
+    }
+    if (!_Py_Gid_Converter(args[2], &gid)) {
         goto exit;
     }
     return_value = os_lchown_impl(module, &path, uid, gid);
@@ -860,17 +1094,49 @@ os_link(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwn
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"src", "dst", "src_dir_fd", "dst_dir_fd", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&O&|$O&O&p:link", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "link", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t src = PATH_T_INITIALIZE("link", "src", 0, 0);
     path_t dst = PATH_T_INITIALIZE("link", "dst", 0, 0);
     int src_dir_fd = DEFAULT_DIR_FD;
     int dst_dir_fd = DEFAULT_DIR_FD;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &src, path_converter, &dst, dir_fd_converter, &src_dir_fd, dir_fd_converter, &dst_dir_fd, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &src)) {
+        goto exit;
+    }
+    if (!path_converter(args[1], &dst)) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        if (!dir_fd_converter(args[2], &src_dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[3]) {
+        if (!dir_fd_converter(args[3], &dst_dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    follow_symlinks = PyObject_IsTrue(args[4]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_link_impl(module, &src, &dst, src_dir_fd, dst_dir_fd, follow_symlinks);
 
 exit:
@@ -912,13 +1178,22 @@ os_listdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"|O&:listdir", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "listdir", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     path_t path = PATH_T_INITIALIZE("listdir", "path", 1, PATH_HAVE_FDOPENDIR);
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+skip_optional_pos:
     return_value = os_listdir_impl(module, &path);
 
 exit:
@@ -1027,11 +1302,15 @@ os__getvolumepathname(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"O&:_getvolumepathname", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_getvolumepathname", 0};
+    PyObject *argsbuf[1];
     path_t path = PATH_T_INITIALIZE("_getvolumepathname", "path", 0, 0);
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
     return_value = os__getvolumepathname_impl(module, &path);
@@ -1069,15 +1348,45 @@ os_mkdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "mode", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|i$O&:mkdir", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "mkdir", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("mkdir", "path", 0, 0);
     int mode = 511;
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &mode, MKDIRAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        mode = _PyLong_AsInt(args[1]);
+        if (mode == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!MKDIRAT_DIR_FD_CONVERTER(args[2], &dir_fd)) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_mkdir_impl(module, &path, mode, dir_fd);
 
 exit:
@@ -1143,12 +1452,31 @@ os_getpriority(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"which", "who", NULL};
-    static _PyArg_Parser _parser = {"ii:getpriority", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "getpriority", 0};
+    PyObject *argsbuf[2];
     int which;
     int who;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &which, &who)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    which = _PyLong_AsInt(args[0]);
+    if (which == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    who = _PyLong_AsInt(args[1]);
+    if (who == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_getpriority_impl(module, which, who);
@@ -1178,13 +1506,41 @@ os_setpriority(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"which", "who", "priority", NULL};
-    static _PyArg_Parser _parser = {"iii:setpriority", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "setpriority", 0};
+    PyObject *argsbuf[3];
     int which;
     int who;
     int priority;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &which, &who, &priority)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    which = _PyLong_AsInt(args[0]);
+    if (which == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    who = _PyLong_AsInt(args[1]);
+    if (who == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    priority = _PyLong_AsInt(args[2]);
+    if (priority == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_setpriority_impl(module, which, who, priority);
@@ -1219,16 +1575,39 @@ os_rename(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"src", "dst", "src_dir_fd", "dst_dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&O&|$O&O&:rename", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "rename", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t src = PATH_T_INITIALIZE("rename", "src", 0, 0);
     path_t dst = PATH_T_INITIALIZE("rename", "dst", 0, 0);
     int src_dir_fd = DEFAULT_DIR_FD;
     int dst_dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &src, path_converter, &dst, dir_fd_converter, &src_dir_fd, dir_fd_converter, &dst_dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &src)) {
+        goto exit;
+    }
+    if (!path_converter(args[1], &dst)) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        if (!dir_fd_converter(args[2], &src_dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (!dir_fd_converter(args[3], &dst_dir_fd)) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_rename_impl(module, &src, &dst, src_dir_fd, dst_dir_fd);
 
 exit:
@@ -1264,16 +1643,39 @@ os_replace(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"src", "dst", "src_dir_fd", "dst_dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&O&|$O&O&:replace", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "replace", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t src = PATH_T_INITIALIZE("replace", "src", 0, 0);
     path_t dst = PATH_T_INITIALIZE("replace", "dst", 0, 0);
     int src_dir_fd = DEFAULT_DIR_FD;
     int dst_dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &src, path_converter, &dst, dir_fd_converter, &src_dir_fd, dir_fd_converter, &dst_dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!path_converter(args[0], &src)) {
+        goto exit;
+    }
+    if (!path_converter(args[1], &dst)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        if (!dir_fd_converter(args[2], &src_dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (!dir_fd_converter(args[3], &dst_dir_fd)) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_replace_impl(module, &src, &dst, src_dir_fd, dst_dir_fd);
 
 exit:
@@ -1307,14 +1709,26 @@ os_rmdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|$O&:rmdir", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "rmdir", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("rmdir", "path", 0, 0);
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, UNLINKAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!UNLINKAT_DIR_FD_CONVERTER(args[1], &dir_fd)) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_rmdir_impl(module, &path, dir_fd);
 
 exit:
@@ -1382,12 +1796,16 @@ os_system(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"command", NULL};
-    static _PyArg_Parser _parser = {"O&:system", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "system", 0};
+    PyObject *argsbuf[1];
     PyObject *command = NULL;
     long _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        PyUnicode_FSConverter, &command)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_FSConverter(args[0], &command)) {
         goto exit;
     }
     _return_value = os_system_impl(module, command);
@@ -1460,14 +1878,26 @@ os_unlink(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|$O&:unlink", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "unlink", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("unlink", "path", 0, 0);
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, UNLINKAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!UNLINKAT_DIR_FD_CONVERTER(args[1], &dir_fd)) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_unlink_impl(module, &path, dir_fd);
 
 exit:
@@ -1499,14 +1929,26 @@ os_remove(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|$O&:remove", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "remove", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("remove", "path", 0, 0);
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, UNLINKAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!UNLINKAT_DIR_FD_CONVERTER(args[1], &dir_fd)) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_remove_impl(module, &path, dir_fd);
 
 exit:
@@ -1582,17 +2024,54 @@ os_utime(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "times", "ns", "dir_fd", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&|O$OO&p:utime", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "utime", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("utime", "path", 0, PATH_UTIME_HAVE_FD);
     PyObject *times = NULL;
     PyObject *ns = NULL;
     int dir_fd = DEFAULT_DIR_FD;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &times, &ns, FUTIMENSAT_DIR_FD_CONVERTER, &dir_fd, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        times = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[2]) {
+        ns = args[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[3]) {
+        if (!FUTIMENSAT_DIR_FD_CONVERTER(args[3], &dir_fd)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    follow_symlinks = PyObject_IsTrue(args[4]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_utime_impl(module, &path, times, ns, dir_fd, follow_symlinks);
 
 exit:
@@ -1619,11 +2098,21 @@ os__exit(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:_exit", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_exit", 0};
+    PyObject *argsbuf[1];
     int status;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os__exit_impl(module, status);
@@ -1702,15 +2191,21 @@ os_execve(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "argv", "env", NULL};
-    static _PyArg_Parser _parser = {"O&OO:execve", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "execve", 0};
+    PyObject *argsbuf[3];
     path_t path = PATH_T_INITIALIZE("execve", "path", 0, PATH_HAVE_FEXECVE);
     PyObject *argv;
     PyObject *env;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &argv, &env)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    argv = args[1];
+    env = args[2];
     return_value = os_execve_impl(module, &path, argv, env);
 
 exit:
@@ -1768,7 +2263,9 @@ os_posix_spawn(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "", "", "file_actions", "setpgroup", "resetids", "setsid", "setsigmask", "setsigdef", "scheduler", NULL};
-    static _PyArg_Parser _parser = {"O&OO|$OOiiOOO:posix_spawn", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "posix_spawn", 0};
+    PyObject *argsbuf[10];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
     path_t path = PATH_T_INITIALIZE("posix_spawn", "path", 0, 0);
     PyObject *argv;
     PyObject *env;
@@ -1780,10 +2277,72 @@ os_posix_spawn(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
     PyObject *setsigdef = NULL;
     PyObject *scheduler = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &argv, &env, &file_actions, &setpgroup, &resetids, &setsid, &setsigmask, &setsigdef, &scheduler)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    argv = args[1];
+    env = args[2];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[3]) {
+        file_actions = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[4]) {
+        setpgroup = args[4];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[5]) {
+        if (PyFloat_Check(args[5])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        resetids = _PyLong_AsInt(args[5]);
+        if (resetids == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[6]) {
+        if (PyFloat_Check(args[6])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        setsid = _PyLong_AsInt(args[6]);
+        if (setsid == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[7]) {
+        setsigmask = args[7];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[8]) {
+        setsigdef = args[8];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    scheduler = args[9];
+skip_optional_kwonly:
     return_value = os_posix_spawn_impl(module, &path, argv, env, file_actions, setpgroup, resetids, setsid, setsigmask, setsigdef, scheduler);
 
 exit:
@@ -1841,7 +2400,9 @@ os_posix_spawnp(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "", "", "file_actions", "setpgroup", "resetids", "setsid", "setsigmask", "setsigdef", "scheduler", NULL};
-    static _PyArg_Parser _parser = {"O&OO|$OOiiOOO:posix_spawnp", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "posix_spawnp", 0};
+    PyObject *argsbuf[10];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
     path_t path = PATH_T_INITIALIZE("posix_spawnp", "path", 0, 0);
     PyObject *argv;
     PyObject *env;
@@ -1853,10 +2414,72 @@ os_posix_spawnp(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
     PyObject *setsigdef = NULL;
     PyObject *scheduler = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &argv, &env, &file_actions, &setpgroup, &resetids, &setsid, &setsigmask, &setsigdef, &scheduler)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    argv = args[1];
+    env = args[2];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[3]) {
+        file_actions = args[3];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[4]) {
+        setpgroup = args[4];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[5]) {
+        if (PyFloat_Check(args[5])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        resetids = _PyLong_AsInt(args[5]);
+        if (resetids == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[6]) {
+        if (PyFloat_Check(args[6])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        setsid = _PyLong_AsInt(args[6]);
+        if (setsid == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[7]) {
+        setsigmask = args[7];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[8]) {
+        setsigdef = args[8];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    scheduler = args[9];
+skip_optional_kwonly:
     return_value = os_posix_spawnp_impl(module, &path, argv, env, file_actions, setpgroup, resetids, setsid, setsigmask, setsigdef, scheduler);
 
 exit:
@@ -2016,15 +2639,34 @@ os_register_at_fork(PyObject *module, PyObject *const *args, Py_ssize_t nargs, P
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"before", "after_in_child", "after_in_parent", NULL};
-    static _PyArg_Parser _parser = {"|$OOO:register_at_fork", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "register_at_fork", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *before = NULL;
     PyObject *after_in_child = NULL;
     PyObject *after_in_parent = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &before, &after_in_child, &after_in_parent)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[0]) {
+        before = args[0];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (args[1]) {
+        after_in_child = args[1];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    after_in_parent = args[2];
+skip_optional_kwonly:
     return_value = os_register_at_fork_impl(module, before, after_in_child, after_in_parent);
 
 exit:
@@ -2100,11 +2742,21 @@ os_sched_get_priority_max(PyObject *module, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"policy", NULL};
-    static _PyArg_Parser _parser = {"i:sched_get_priority_max", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sched_get_priority_max", 0};
+    PyObject *argsbuf[1];
     int policy;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &policy)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    policy = _PyLong_AsInt(args[0]);
+    if (policy == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_sched_get_priority_max_impl(module, policy);
@@ -2134,11 +2786,21 @@ os_sched_get_priority_min(PyObject *module, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"policy", NULL};
-    static _PyArg_Parser _parser = {"i:sched_get_priority_min", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sched_get_priority_min", 0};
+    PyObject *argsbuf[1];
     int policy;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &policy)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    policy = _PyLong_AsInt(args[0]);
+    if (policy == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_sched_get_priority_min_impl(module, policy);
@@ -2201,13 +2863,17 @@ os_sched_param(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sched_priority", NULL};
-    static _PyArg_Parser _parser = {"O:sched_param", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sched_param", 0};
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     PyObject *sched_priority;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &sched_priority)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    sched_priority = fastargs[0];
     return_value = os_sched_param_impl(type, sched_priority);
 
 exit:
@@ -3100,11 +3766,21 @@ os_wait3(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"options", NULL};
-    static _PyArg_Parser _parser = {"i:wait3", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "wait3", 0};
+    PyObject *argsbuf[1];
     int options;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &options)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    options = _PyLong_AsInt(args[0]);
+    if (options == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_wait3_impl(module, options);
@@ -3324,14 +4000,26 @@ os_readlink(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|$O&:readlink", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "readlink", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("readlink", "path", 0, 0);
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, READLINKAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!READLINKAT_DIR_FD_CONVERTER(args[1], &dir_fd)) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_readlink_impl(module, &path, dir_fd);
 
 exit:
@@ -3373,16 +4061,44 @@ os_symlink(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"src", "dst", "target_is_directory", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&O&|p$O&:symlink", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "symlink", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t src = PATH_T_INITIALIZE("symlink", "src", 0, 0);
     path_t dst = PATH_T_INITIALIZE("symlink", "dst", 0, 0);
     int target_is_directory = 0;
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &src, path_converter, &dst, &target_is_directory, SYMLINKAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &src)) {
+        goto exit;
+    }
+    if (!path_converter(args[1], &dst)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        target_is_directory = PyObject_IsTrue(args[2]);
+        if (target_is_directory < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!SYMLINKAT_DIR_FD_CONVERTER(args[3], &dir_fd)) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_symlink_impl(module, &src, &dst, target_is_directory, dir_fd);
 
 exit:
@@ -3600,17 +4316,56 @@ os_open(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwn
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "flags", "mode", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&i|i$O&:open", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "open", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t path = PATH_T_INITIALIZE("open", "path", 0, 0);
     int flags;
     int mode = 511;
     int dir_fd = DEFAULT_DIR_FD;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &flags, &mode, OPENAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    flags = _PyLong_AsInt(args[1]);
+    if (flags == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[2]) {
+        if (PyFloat_Check(args[2])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        mode = _PyLong_AsInt(args[2]);
+        if (mode == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!OPENAT_DIR_FD_CONVERTER(args[3], &dir_fd)) {
+        goto exit;
+    }
+skip_optional_kwonly:
     _return_value = os_open_impl(module, &path, flags, mode, dir_fd);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -3641,11 +4396,21 @@ os_close(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", NULL};
-    static _PyArg_Parser _parser = {"i:close", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "close", 0};
+    PyObject *argsbuf[1];
     int fd;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    fd = _PyLong_AsInt(args[0]);
+    if (fd == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_close_impl(module, fd);
@@ -3755,16 +4520,44 @@ os_dup2(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwn
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", "fd2", "inheritable", NULL};
-    static _PyArg_Parser _parser = {"ii|p:dup2", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "dup2", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     int fd;
     int fd2;
     int inheritable = 1;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &fd, &fd2, &inheritable)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    fd = _PyLong_AsInt(args[0]);
+    if (fd == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    fd2 = _PyLong_AsInt(args[1]);
+    if (fd2 == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    inheritable = PyObject_IsTrue(args[2]);
+    if (inheritable < 0) {
+        goto exit;
+    }
+skip_optional_pos:
     _return_value = os_dup2_impl(module, fd, fd2, inheritable);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -4274,11 +5067,21 @@ os_fstat(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", NULL};
-    static _PyArg_Parser _parser = {"i:fstat", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fstat", 0};
+    PyObject *argsbuf[1];
     int fd;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    fd = _PyLong_AsInt(args[0]);
+    if (fd == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_fstat_impl(module, fd);
@@ -4616,15 +5419,45 @@ os_mkfifo(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "mode", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|i$O&:mkfifo", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "mkfifo", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("mkfifo", "path", 0, 0);
     int mode = 438;
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &mode, MKFIFOAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        mode = _PyLong_AsInt(args[1]);
+        if (mode == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!MKFIFOAT_DIR_FD_CONVERTER(args[2], &dir_fd)) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_mkfifo_impl(module, &path, mode, dir_fd);
 
 exit:
@@ -4668,16 +5501,54 @@ os_mknod(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kw
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "mode", "device", "dir_fd", NULL};
-    static _PyArg_Parser _parser = {"O&|iO&$O&:mknod", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "mknod", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     path_t path = PATH_T_INITIALIZE("mknod", "path", 0, 0);
     int mode = 384;
     dev_t device = 0;
     int dir_fd = DEFAULT_DIR_FD;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &mode, _Py_Dev_Converter, &device, MKNODAT_DIR_FD_CONVERTER, &dir_fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        mode = _PyLong_AsInt(args[1]);
+        if (mode == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[2]) {
+        if (!_Py_Dev_Converter(args[2], &device)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (!MKNODAT_DIR_FD_CONVERTER(args[3], &dir_fd)) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_mknod_impl(module, &path, mode, device, dir_fd);
 
 exit:
@@ -4882,12 +5753,19 @@ os_truncate(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "length", NULL};
-    static _PyArg_Parser _parser = {"O&O&:truncate", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "truncate", 0};
+    PyObject *argsbuf[2];
     path_t path = PATH_T_INITIALIZE("truncate", "path", 0, PATH_HAVE_FTRUNCATE);
     Py_off_t length;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, Py_off_t_converter, &length)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!Py_off_t_converter(args[1], &length)) {
         goto exit;
     }
     return_value = os_truncate_impl(module, &path, length);
@@ -5242,12 +6120,22 @@ os_WIFCONTINUED(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:WIFCONTINUED", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "WIFCONTINUED", 0};
+    PyObject *argsbuf[1];
     int status;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     _return_value = os_WIFCONTINUED_impl(module, status);
@@ -5281,12 +6169,22 @@ os_WIFSTOPPED(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:WIFSTOPPED", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "WIFSTOPPED", 0};
+    PyObject *argsbuf[1];
     int status;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     _return_value = os_WIFSTOPPED_impl(module, status);
@@ -5320,12 +6218,22 @@ os_WIFSIGNALED(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:WIFSIGNALED", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "WIFSIGNALED", 0};
+    PyObject *argsbuf[1];
     int status;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     _return_value = os_WIFSIGNALED_impl(module, status);
@@ -5359,12 +6267,22 @@ os_WIFEXITED(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:WIFEXITED", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "WIFEXITED", 0};
+    PyObject *argsbuf[1];
     int status;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     _return_value = os_WIFEXITED_impl(module, status);
@@ -5398,12 +6316,22 @@ os_WEXITSTATUS(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:WEXITSTATUS", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "WEXITSTATUS", 0};
+    PyObject *argsbuf[1];
     int status;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     _return_value = os_WEXITSTATUS_impl(module, status);
@@ -5437,12 +6365,22 @@ os_WTERMSIG(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:WTERMSIG", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "WTERMSIG", 0};
+    PyObject *argsbuf[1];
     int status;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     _return_value = os_WTERMSIG_impl(module, status);
@@ -5476,12 +6414,22 @@ os_WSTOPSIG(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"status", NULL};
-    static _PyArg_Parser _parser = {"i:WSTOPSIG", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "WSTOPSIG", 0};
+    PyObject *argsbuf[1];
     int status;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &status)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    status = _PyLong_AsInt(args[0]);
+    if (status == -1 && PyErr_Occurred()) {
         goto exit;
     }
     _return_value = os_WSTOPSIG_impl(module, status);
@@ -5558,11 +6506,15 @@ os_statvfs(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"O&:statvfs", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "statvfs", 0};
+    PyObject *argsbuf[1];
     path_t path = PATH_T_INITIALIZE("statvfs", "path", 0, PATH_HAVE_FSTATVFS);
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
     return_value = os_statvfs_impl(module, &path);
@@ -5595,11 +6547,15 @@ os__getdiskusage(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"O&:_getdiskusage", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "_getdiskusage", 0};
+    PyObject *argsbuf[1];
     path_t path = PATH_T_INITIALIZE("_getdiskusage", "path", 0, 0);
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
     return_value = os__getdiskusage_impl(module, &path);
@@ -5687,13 +6643,20 @@ os_pathconf(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "name", NULL};
-    static _PyArg_Parser _parser = {"O&O&:pathconf", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "pathconf", 0};
+    PyObject *argsbuf[2];
     path_t path = PATH_T_INITIALIZE("pathconf", "path", 0, PATH_HAVE_FPATHCONF);
     int name;
     long _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, conv_path_confname, &name)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!conv_path_confname(args[1], &name)) {
         goto exit;
     }
     _return_value = os_pathconf_impl(module, &path, name);
@@ -5901,11 +6864,21 @@ os_device_encoding(PyObject *module, PyObject *const *args, Py_ssize_t nargs, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", NULL};
-    static _PyArg_Parser _parser = {"i:device_encoding", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "device_encoding", 0};
+    PyObject *argsbuf[1];
     int fd;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    fd = _PyLong_AsInt(args[0]);
+    if (fd == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = os_device_encoding_impl(module, fd);
@@ -6067,15 +7040,31 @@ os_getxattr(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "attribute", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&O&|$p:getxattr", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "getxattr", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t path = PATH_T_INITIALIZE("getxattr", "path", 0, 1);
     path_t attribute = PATH_T_INITIALIZE("getxattr", "attribute", 0, 0);
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, path_converter, &attribute, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!path_converter(args[1], &attribute)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    follow_symlinks = PyObject_IsTrue(args[2]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_getxattr_impl(module, &path, &attribute, follow_symlinks);
 
 exit:
@@ -6115,17 +7104,58 @@ os_setxattr(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "attribute", "value", "flags", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&O&y*|i$p:setxattr", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "setxattr", 0};
+    PyObject *argsbuf[5];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
     path_t path = PATH_T_INITIALIZE("setxattr", "path", 0, 1);
     path_t attribute = PATH_T_INITIALIZE("setxattr", "attribute", 0, 0);
     Py_buffer value = {NULL, NULL};
     int flags = 0;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, path_converter, &attribute, &value, &flags, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 4, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!path_converter(args[1], &attribute)) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[2], &value, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&value, 'C')) {
+        _PyArg_BadArgument("setxattr", 3, "contiguous buffer", args[2]);
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[3]) {
+        if (PyFloat_Check(args[3])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        flags = _PyLong_AsInt(args[3]);
+        if (flags == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    follow_symlinks = PyObject_IsTrue(args[4]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_setxattr_impl(module, &path, &attribute, &value, flags, follow_symlinks);
 
 exit:
@@ -6168,15 +7198,31 @@ os_removexattr(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "attribute", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"O&O&|$p:removexattr", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "removexattr", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     path_t path = PATH_T_INITIALIZE("removexattr", "path", 0, 1);
     path_t attribute = PATH_T_INITIALIZE("removexattr", "attribute", 0, 0);
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, path_converter, &attribute, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!path_converter(args[0], &path)) {
+        goto exit;
+    }
+    if (!path_converter(args[1], &attribute)) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    follow_symlinks = PyObject_IsTrue(args[2]);
+    if (follow_symlinks < 0) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_removexattr_impl(module, &path, &attribute, follow_symlinks);
 
 exit:
@@ -6215,14 +7261,36 @@ os_listxattr(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", "follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"|O&$p:listxattr", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "listxattr", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     path_t path = PATH_T_INITIALIZE("listxattr", "path", 1, 1);
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path, &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (!path_converter(args[0], &path)) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    follow_symlinks = PyObject_IsTrue(args[1]);
+    if (follow_symlinks < 0) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = os_listxattr_impl(module, &path, follow_symlinks);
 
 exit:
@@ -6593,13 +7661,23 @@ os_DirEntry_stat(DirEntry *self, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"|$p:stat", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "stat", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int follow_symlinks = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    follow_symlinks = PyObject_IsTrue(args[0]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = os_DirEntry_stat_impl(self, follow_symlinks);
 
 exit:
@@ -6623,14 +7701,24 @@ os_DirEntry_is_dir(DirEntry *self, PyObject *const *args, Py_ssize_t nargs, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"|$p:is_dir", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "is_dir", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int follow_symlinks = 1;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    follow_symlinks = PyObject_IsTrue(args[0]);
+    if (follow_symlinks < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     _return_value = os_DirEntry_is_dir_impl(self, follow_symlinks);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -6658,14 +7746,24 @@ os_DirEntry_is_file(DirEntry *self, PyObject *const *args, Py_ssize_t nargs, PyO
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"follow_symlinks", NULL};
-    static _PyArg_Parser _parser = {"|$p:is_file", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "is_file", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int follow_symlinks = 1;
     int _return_value;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &follow_symlinks)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    follow_symlinks = PyObject_IsTrue(args[0]);
+    if (follow_symlinks < 0) {
         goto exit;
     }
+skip_optional_kwonly:
     _return_value = os_DirEntry_is_file_impl(self, follow_symlinks);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
@@ -6735,13 +7833,22 @@ os_scandir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"|O&:scandir", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "scandir", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     path_t path = PATH_T_INITIALIZE("scandir", "path", 1, PATH_HAVE_FDOPENDIR);
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        path_converter, &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (!path_converter(args[0], &path)) {
         goto exit;
     }
+skip_optional_pos:
     return_value = os_scandir_impl(module, &path);
 
 exit:
@@ -6772,13 +7879,15 @@ os_fspath(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *k
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"path", NULL};
-    static _PyArg_Parser _parser = {"O:fspath", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fspath", 0};
+    PyObject *argsbuf[1];
     PyObject *path;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &path)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    path = args[0];
     return_value = os_fspath_impl(module, path);
 
 exit:
@@ -6804,14 +7913,46 @@ os_getrandom(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"size", "flags", NULL};
-    static _PyArg_Parser _parser = {"n|i:getrandom", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "getrandom", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_ssize_t size;
     int flags = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &size, &flags)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[0]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        size = ival;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    flags = _PyLong_AsInt(args[1]);
+    if (flags == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = os_getrandom_impl(module, size, flags);
 
 exit:
@@ -7339,4 +8480,4 @@ exit:
 #ifndef OS_GETRANDOM_METHODDEF
     #define OS_GETRANDOM_METHODDEF
 #endif /* !defined(OS_GETRANDOM_METHODDEF) */
-/*[clinic end generated code: output=bb677205c036deca input=a9049054013a1b77]*/
+/*[clinic end generated code: output=1a9c62f5841221ae input=a9049054013a1b77]*/
diff --git a/Modules/clinic/pyexpat.c.h b/Modules/clinic/pyexpat.c.h
index 3fe7b64e6f..dfb27d5f11 100644
--- a/Modules/clinic/pyexpat.c.h
+++ b/Modules/clinic/pyexpat.c.h
@@ -297,15 +297,68 @@ pyexpat_ParserCreate(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"encoding", "namespace_separator", "intern", NULL};
-    static _PyArg_Parser _parser = {"|zzO:ParserCreate", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "ParserCreate", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     const char *encoding = NULL;
     const char *namespace_separator = NULL;
     PyObject *intern = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &encoding, &namespace_separator, &intern)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (args[0] == Py_None) {
+            encoding = NULL;
+        }
+        else if (PyUnicode_Check(args[0])) {
+            Py_ssize_t encoding_length;
+            encoding = PyUnicode_AsUTF8AndSize(args[0], &encoding_length);
+            if (encoding == NULL) {
+                goto exit;
+            }
+            if (strlen(encoding) != (size_t)encoding_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("ParserCreate", 1, "str or None", args[0]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[1]) {
+        if (args[1] == Py_None) {
+            namespace_separator = NULL;
+        }
+        else if (PyUnicode_Check(args[1])) {
+            Py_ssize_t namespace_separator_length;
+            namespace_separator = PyUnicode_AsUTF8AndSize(args[1], &namespace_separator_length);
+            if (namespace_separator == NULL) {
+                goto exit;
+            }
+            if (strlen(namespace_separator) != (size_t)namespace_separator_length) {
+                PyErr_SetString(PyExc_ValueError, "embedded null character");
+                goto exit;
+            }
+        }
+        else {
+            _PyArg_BadArgument("ParserCreate", 2, "str or None", args[1]);
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    intern = args[2];
+skip_optional_pos:
     return_value = pyexpat_ParserCreate_impl(module, encoding, namespace_separator, intern);
 
 exit:
@@ -348,4 +401,4 @@ exit:
 #ifndef PYEXPAT_XMLPARSER_USEFOREIGNDTD_METHODDEF
     #define PYEXPAT_XMLPARSER_USEFOREIGNDTD_METHODDEF
 #endif /* !defined(PYEXPAT_XMLPARSER_USEFOREIGNDTD_METHODDEF) */
-/*[clinic end generated code: output=0f18b756d82b78a5 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=e48f37d326956bdd input=a9049054013a1b77]*/
diff --git a/Modules/clinic/selectmodule.c.h b/Modules/clinic/selectmodule.c.h
index c2ef26f240..9015816f80 100644
--- a/Modules/clinic/selectmodule.c.h
+++ b/Modules/clinic/selectmodule.c.h
@@ -512,14 +512,45 @@ select_epoll(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sizehint", "flags", NULL};
-    static _PyArg_Parser _parser = {"|ii:epoll", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "epoll", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     int sizehint = -1;
     int flags = 0;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &sizehint, &flags)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[0]) {
+        if (PyFloat_Check(fastargs[0])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        sizehint = _PyLong_AsInt(fastargs[0]);
+        if (sizehint == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(fastargs[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    flags = _PyLong_AsInt(fastargs[1]);
+    if (flags == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = select_epoll_impl(type, sizehint, flags);
 
 exit:
@@ -638,14 +669,32 @@ select_epoll_register(pyEpoll_Object *self, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", "eventmask", NULL};
-    static _PyArg_Parser _parser = {"O&|I:register", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "register", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     int fd;
     unsigned int eventmask = EPOLLIN | EPOLLPRI | EPOLLOUT;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        fildes_converter, &fd, &eventmask)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!fildes_converter(args[0], &fd)) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    eventmask = (unsigned int)PyLong_AsUnsignedLongMask(args[1]);
+    if (eventmask == (unsigned int)-1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = select_epoll_register_impl(self, fd, eventmask);
 
 exit:
@@ -679,12 +728,25 @@ select_epoll_modify(pyEpoll_Object *self, PyObject *const *args, Py_ssize_t narg
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", "eventmask", NULL};
-    static _PyArg_Parser _parser = {"O&I:modify", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "modify", 0};
+    PyObject *argsbuf[2];
     int fd;
     unsigned int eventmask;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        fildes_converter, &fd, &eventmask)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!fildes_converter(args[0], &fd)) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    eventmask = (unsigned int)PyLong_AsUnsignedLongMask(args[1]);
+    if (eventmask == (unsigned int)-1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = select_epoll_modify_impl(self, fd, eventmask);
@@ -717,11 +779,15 @@ select_epoll_unregister(pyEpoll_Object *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"fd", NULL};
-    static _PyArg_Parser _parser = {"O&:unregister", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "unregister", 0};
+    PyObject *argsbuf[1];
     int fd;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        fildes_converter, &fd)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!fildes_converter(args[0], &fd)) {
         goto exit;
     }
     return_value = select_epoll_unregister_impl(self, fd);
@@ -761,14 +827,35 @@ select_epoll_poll(pyEpoll_Object *self, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"timeout", "maxevents", NULL};
-    static _PyArg_Parser _parser = {"|Oi:poll", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "poll", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *timeout_obj = Py_None;
     int maxevents = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &timeout_obj, &maxevents)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        timeout_obj = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    maxevents = _PyLong_AsInt(args[1]);
+    if (maxevents == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = select_epoll_poll_impl(self, timeout_obj, maxevents);
 
 exit:
@@ -1128,4 +1215,4 @@ exit:
 #ifndef SELECT_KQUEUE_CONTROL_METHODDEF
     #define SELECT_KQUEUE_CONTROL_METHODDEF
 #endif /* !defined(SELECT_KQUEUE_CONTROL_METHODDEF) */
-/*[clinic end generated code: output=3e40b33a3294d03d input=a9049054013a1b77]*/
+/*[clinic end generated code: output=03041f3d09b04a3d input=a9049054013a1b77]*/
diff --git a/Modules/clinic/sha1module.c.h b/Modules/clinic/sha1module.c.h
index af29173bae..001c6af737 100644
--- a/Modules/clinic/sha1module.c.h
+++ b/Modules/clinic/sha1module.c.h
@@ -82,16 +82,23 @@ _sha1_sha1(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", NULL};
-    static _PyArg_Parser _parser = {"|O:sha1", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sha1", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *string = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    string = args[0];
+skip_optional_pos:
     return_value = _sha1_sha1_impl(module, string);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=3bae85313ee5a3b5 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=1ae7e73ec84a27d5 input=a9049054013a1b77]*/
diff --git a/Modules/clinic/sha256module.c.h b/Modules/clinic/sha256module.c.h
index 14a88a2be8..658abb15cf 100644
--- a/Modules/clinic/sha256module.c.h
+++ b/Modules/clinic/sha256module.c.h
@@ -82,13 +82,20 @@ _sha256_sha256(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", NULL};
-    static _PyArg_Parser _parser = {"|O:sha256", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sha256", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *string = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    string = args[0];
+skip_optional_pos:
     return_value = _sha256_sha256_impl(module, string);
 
 exit:
@@ -112,16 +119,23 @@ _sha256_sha224(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", NULL};
-    static _PyArg_Parser _parser = {"|O:sha224", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sha224", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *string = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    string = args[0];
+skip_optional_pos:
     return_value = _sha256_sha224_impl(module, string);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=fb208641d4bc3b5f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=c54d0956ec88409d input=a9049054013a1b77]*/
diff --git a/Modules/clinic/sha512module.c.h b/Modules/clinic/sha512module.c.h
index 7e08701937..459a9341cf 100644
--- a/Modules/clinic/sha512module.c.h
+++ b/Modules/clinic/sha512module.c.h
@@ -82,13 +82,20 @@ _sha512_sha512(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", NULL};
-    static _PyArg_Parser _parser = {"|O:sha512", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sha512", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *string = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    string = args[0];
+skip_optional_pos:
     return_value = _sha512_sha512_impl(module, string);
 
 exit:
@@ -112,16 +119,23 @@ _sha512_sha384(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"string", NULL};
-    static _PyArg_Parser _parser = {"|O:sha384", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sha384", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *string = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &string)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    string = args[0];
+skip_optional_pos:
     return_value = _sha512_sha384_impl(module, string);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=3706fa47bea06c0b input=a9049054013a1b77]*/
+/*[clinic end generated code: output=580df4b667084a7e input=a9049054013a1b77]*/
diff --git a/Modules/clinic/zlibmodule.c.h b/Modules/clinic/zlibmodule.c.h
index 8e5f96aa14..aa57920910 100644
--- a/Modules/clinic/zlibmodule.c.h
+++ b/Modules/clinic/zlibmodule.c.h
@@ -24,14 +24,36 @@ zlib_compress(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "level", NULL};
-    static _PyArg_Parser _parser = {"y*|i:compress", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "compress", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     int level = Z_DEFAULT_COMPRESSION;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &level)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("compress", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    level = _PyLong_AsInt(args[1]);
+    if (level == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = zlib_compress_impl(module, &data, level);
 
 exit:
@@ -68,15 +90,45 @@ zlib_decompress(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "wbits", "bufsize", NULL};
-    static _PyArg_Parser _parser = {"y*|iO&:decompress", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decompress", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     int wbits = MAX_WBITS;
     Py_ssize_t bufsize = DEF_BUF_SIZE;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, &wbits, ssize_t_converter, &bufsize)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("decompress", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        wbits = _PyLong_AsInt(args[1]);
+        if (wbits == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (!ssize_t_converter(args[2], &bufsize)) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = zlib_decompress_impl(module, &data, wbits, bufsize);
 
 exit:
@@ -130,7 +182,9 @@ zlib_compressobj(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"level", "method", "wbits", "memLevel", "strategy", "zdict", NULL};
-    static _PyArg_Parser _parser = {"|iiiiiy*:compressobj", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "compressobj", 0};
+    PyObject *argsbuf[6];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int level = Z_DEFAULT_COMPRESSION;
     int method = DEFLATED;
     int wbits = MAX_WBITS;
@@ -138,10 +192,91 @@ zlib_compressobj(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
     int strategy = Z_DEFAULT_STRATEGY;
     Py_buffer zdict = {NULL, NULL};
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &level, &method, &wbits, &memLevel, &strategy, &zdict)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 6, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (PyFloat_Check(args[0])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        level = _PyLong_AsInt(args[0]);
+        if (level == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[1]) {
+        if (PyFloat_Check(args[1])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        method = _PyLong_AsInt(args[1]);
+        if (method == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[2]) {
+        if (PyFloat_Check(args[2])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        wbits = _PyLong_AsInt(args[2]);
+        if (wbits == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[3]) {
+        if (PyFloat_Check(args[3])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        memLevel = _PyLong_AsInt(args[3]);
+        if (memLevel == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[4]) {
+        if (PyFloat_Check(args[4])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        strategy = _PyLong_AsInt(args[4]);
+        if (strategy == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyObject_GetBuffer(args[5], &zdict, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&zdict, 'C')) {
+        _PyArg_BadArgument("compressobj", 6, "contiguous buffer", args[5]);
+        goto exit;
+    }
+skip_optional_pos:
     return_value = zlib_compressobj_impl(module, level, method, wbits, memLevel, strategy, &zdict);
 
 exit:
@@ -176,14 +311,35 @@ zlib_decompressobj(PyObject *module, PyObject *const *args, Py_ssize_t nargs, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"wbits", "zdict", NULL};
-    static _PyArg_Parser _parser = {"|iO:decompressobj", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decompressobj", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int wbits = MAX_WBITS;
     PyObject *zdict = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &wbits, &zdict)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (PyFloat_Check(args[0])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        wbits = _PyLong_AsInt(args[0]);
+        if (wbits == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    zdict = args[1];
+skip_optional_pos:
     return_value = zlib_decompressobj_impl(module, wbits, zdict);
 
 exit:
@@ -262,14 +418,30 @@ zlib_Decompress_decompress(compobject *self, PyObject *const *args, Py_ssize_t n
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "max_length", NULL};
-    static _PyArg_Parser _parser = {"y*|O&:decompress", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decompress", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     Py_buffer data = {NULL, NULL};
     Py_ssize_t max_length = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &data, ssize_t_converter, &max_length)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[0], &data, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&data, 'C')) {
+        _PyArg_BadArgument("decompress", 1, "contiguous buffer", args[0]);
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (!ssize_t_converter(args[1], &max_length)) {
         goto exit;
     }
+skip_optional_pos:
     return_value = zlib_Decompress_decompress_impl(self, &data, max_length);
 
 exit:
@@ -613,4 +785,4 @@ exit:
 #ifndef ZLIB_DECOMPRESS___DEEPCOPY___METHODDEF
     #define ZLIB_DECOMPRESS___DEEPCOPY___METHODDEF
 #endif /* !defined(ZLIB_DECOMPRESS___DEEPCOPY___METHODDEF) */
-/*[clinic end generated code: output=b3acec2384f18782 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=feb079cebbbaacd6 input=a9049054013a1b77]*/
diff --git a/Objects/clinic/bytearrayobject.c.h b/Objects/clinic/bytearrayobject.c.h
index a4669f5076..da1dc6a40a 100644
--- a/Objects/clinic/bytearrayobject.c.h
+++ b/Objects/clinic/bytearrayobject.c.h
@@ -62,14 +62,22 @@ bytearray_translate(PyByteArrayObject *self, PyObject *const *args, Py_ssize_t n
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "delete", NULL};
-    static _PyArg_Parser _parser = {"O|O:translate", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "translate", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *table;
     PyObject *deletechars = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &table, &deletechars)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    table = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    deletechars = args[1];
+skip_optional_pos:
     return_value = bytearray_translate_impl(self, table, deletechars);
 
 exit:
@@ -239,14 +247,43 @@ bytearray_split(PyByteArrayObject *self, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sep", "maxsplit", NULL};
-    static _PyArg_Parser _parser = {"|On:split", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "split", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *sep = Py_None;
     Py_ssize_t maxsplit = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &sep, &maxsplit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        sep = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        maxsplit = ival;
+    }
+skip_optional_pos:
     return_value = bytearray_split_impl(self, sep, maxsplit);
 
 exit:
@@ -314,14 +351,43 @@ bytearray_rsplit(PyByteArrayObject *self, PyObject *const *args, Py_ssize_t narg
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sep", "maxsplit", NULL};
-    static _PyArg_Parser _parser = {"|On:rsplit", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "rsplit", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *sep = Py_None;
     Py_ssize_t maxsplit = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &sep, &maxsplit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        sep = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        maxsplit = ival;
+    }
+skip_optional_pos:
     return_value = bytearray_rsplit_impl(self, sep, maxsplit);
 
 exit:
@@ -654,14 +720,51 @@ bytearray_decode(PyByteArrayObject *self, PyObject *const *args, Py_ssize_t narg
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"|ss:decode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     const char *encoding = NULL;
     const char *errors = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &encoding, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (!PyUnicode_Check(args[0])) {
+            _PyArg_BadArgument("decode", 1, "str", args[0]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(args[0], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (!PyUnicode_Check(args[1])) {
+        _PyArg_BadArgument("decode", 2, "str", args[1]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(args[1], &errors_length);
+    if (errors == NULL) {
+        goto exit;
+    }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+skip_optional_pos:
     return_value = bytearray_decode_impl(self, encoding, errors);
 
 exit:
@@ -701,13 +804,28 @@ bytearray_splitlines(PyByteArrayObject *self, PyObject *const *args, Py_ssize_t
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"keepends", NULL};
-    static _PyArg_Parser _parser = {"|i:splitlines", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "splitlines", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int keepends = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &keepends)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    keepends = _PyLong_AsInt(args[0]);
+    if (keepends == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = bytearray_splitlines_impl(self, keepends);
 
 exit:
@@ -824,4 +942,4 @@ bytearray_sizeof(PyByteArrayObject *self, PyObject *Py_UNUSED(ignored))
 {
     return bytearray_sizeof_impl(self);
 }
-/*[clinic end generated code: output=f4353c27dcb4a13d input=a9049054013a1b77]*/
+/*[clinic end generated code: output=272fcb836b92da32 input=a9049054013a1b77]*/
diff --git a/Objects/clinic/bytesobject.c.h b/Objects/clinic/bytesobject.c.h
index d75bbf1e54..b03078305a 100644
--- a/Objects/clinic/bytesobject.c.h
+++ b/Objects/clinic/bytesobject.c.h
@@ -27,14 +27,43 @@ bytes_split(PyBytesObject *self, PyObject *const *args, Py_ssize_t nargs, PyObje
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sep", "maxsplit", NULL};
-    static _PyArg_Parser _parser = {"|On:split", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "split", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *sep = Py_None;
     Py_ssize_t maxsplit = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &sep, &maxsplit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        sep = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        maxsplit = ival;
+    }
+skip_optional_pos:
     return_value = bytes_split_impl(self, sep, maxsplit);
 
 exit:
@@ -154,14 +183,43 @@ bytes_rsplit(PyBytesObject *self, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sep", "maxsplit", NULL};
-    static _PyArg_Parser _parser = {"|On:rsplit", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "rsplit", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *sep = Py_None;
     Py_ssize_t maxsplit = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &sep, &maxsplit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        sep = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        maxsplit = ival;
+    }
+skip_optional_pos:
     return_value = bytes_rsplit_impl(self, sep, maxsplit);
 
 exit:
@@ -309,14 +367,22 @@ bytes_translate(PyBytesObject *self, PyObject *const *args, Py_ssize_t nargs, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "delete", NULL};
-    static _PyArg_Parser _parser = {"O|O:translate", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "translate", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *table;
     PyObject *deletechars = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &table, &deletechars)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    table = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    deletechars = args[1];
+skip_optional_pos:
     return_value = bytes_translate_impl(self, table, deletechars);
 
 exit:
@@ -487,14 +553,51 @@ bytes_decode(PyBytesObject *self, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"|ss:decode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "decode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     const char *encoding = NULL;
     const char *errors = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &encoding, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (!PyUnicode_Check(args[0])) {
+            _PyArg_BadArgument("decode", 1, "str", args[0]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(args[0], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (!PyUnicode_Check(args[1])) {
+        _PyArg_BadArgument("decode", 2, "str", args[1]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(args[1], &errors_length);
+    if (errors == NULL) {
+        goto exit;
+    }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
         goto exit;
     }
+skip_optional_pos:
     return_value = bytes_decode_impl(self, encoding, errors);
 
 exit:
@@ -521,13 +624,28 @@ bytes_splitlines(PyBytesObject *self, PyObject *const *args, Py_ssize_t nargs, P
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"keepends", NULL};
-    static _PyArg_Parser _parser = {"|i:splitlines", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "splitlines", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int keepends = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &keepends)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    keepends = _PyLong_AsInt(args[0]);
+    if (keepends == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = bytes_splitlines_impl(self, keepends);
 
 exit:
@@ -568,4 +686,4 @@ bytes_fromhex(PyTypeObject *type, PyObject *arg)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=c6621bda84e63e51 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=af9f51b9b185567d input=a9049054013a1b77]*/
diff --git a/Objects/clinic/complexobject.c.h b/Objects/clinic/complexobject.c.h
index 0cbfb793e1..8caa910d03 100644
--- a/Objects/clinic/complexobject.c.h
+++ b/Objects/clinic/complexobject.c.h
@@ -18,17 +18,32 @@ complex_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"real", "imag", NULL};
-    static _PyArg_Parser _parser = {"|OO:complex", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "complex", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *r = _PyLong_Zero;
     PyObject *i = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &r, &i)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[0]) {
+        r = fastargs[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    i = fastargs[1];
+skip_optional_pos:
     return_value = complex_new_impl(type, r, i);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=5017b2458bdc4ecd input=a9049054013a1b77]*/
+/*[clinic end generated code: output=a0fe23fdbdc9b06b input=a9049054013a1b77]*/
diff --git a/Objects/clinic/descrobject.c.h b/Objects/clinic/descrobject.c.h
index 71b196621c..d248b91bf4 100644
--- a/Objects/clinic/descrobject.c.h
+++ b/Objects/clinic/descrobject.c.h
@@ -10,13 +10,17 @@ mappingproxy_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"mapping", NULL};
-    static _PyArg_Parser _parser = {"O:mappingproxy", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "mappingproxy", 0};
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     PyObject *mapping;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &mapping)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    mapping = fastargs[0];
     return_value = mappingproxy_new_impl(type, mapping);
 
 exit:
@@ -69,19 +73,46 @@ property_init(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"fget", "fset", "fdel", "doc", NULL};
-    static _PyArg_Parser _parser = {"|OOOO:property", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "property", 0};
+    PyObject *argsbuf[4];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *fget = NULL;
     PyObject *fset = NULL;
     PyObject *fdel = NULL;
     PyObject *doc = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &fget, &fset, &fdel, &doc)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 4, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[0]) {
+        fget = fastargs[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[1]) {
+        fset = fastargs[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[2]) {
+        fdel = fastargs[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    doc = fastargs[3];
+skip_optional_pos:
     return_value = property_init_impl((propertyobject *)self, fget, fset, fdel, doc);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=729021fa9cdc46be input=a9049054013a1b77]*/
+/*[clinic end generated code: output=916624e717862abc input=a9049054013a1b77]*/
diff --git a/Objects/clinic/enumobject.c.h b/Objects/clinic/enumobject.c.h
index 27da294219..09d4c87e15 100644
--- a/Objects/clinic/enumobject.c.h
+++ b/Objects/clinic/enumobject.c.h
@@ -25,14 +25,24 @@ enum_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"iterable", "start", NULL};
-    static _PyArg_Parser _parser = {"O|O:enumerate", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "enumerate", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *iterable;
     PyObject *start = 0;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &iterable, &start)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    iterable = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    start = fastargs[1];
+skip_optional_pos:
     return_value = enum_new_impl(type, iterable, start);
 
 exit:
@@ -67,4 +77,4 @@ reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=831cec3db0e987c9 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=e18c3fefcf914ec7 input=a9049054013a1b77]*/
diff --git a/Objects/clinic/funcobject.c.h b/Objects/clinic/funcobject.c.h
index 4c54483fe6..929797bfb0 100644
--- a/Objects/clinic/funcobject.c.h
+++ b/Objects/clinic/funcobject.c.h
@@ -28,20 +28,51 @@ func_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"code", "globals", "name", "argdefs", "closure", NULL};
-    static _PyArg_Parser _parser = {"O!O!|OOO:function", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "function", 0};
+    PyObject *argsbuf[5];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 2;
     PyCodeObject *code;
     PyObject *globals;
     PyObject *name = Py_None;
     PyObject *defaults = Py_None;
     PyObject *closure = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &PyCode_Type, &code, &PyDict_Type, &globals, &name, &defaults, &closure)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 2, 5, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!PyObject_TypeCheck(fastargs[0], &PyCode_Type)) {
+        _PyArg_BadArgument("function", 1, (&PyCode_Type)->tp_name, fastargs[0]);
+        goto exit;
+    }
+    code = (PyCodeObject *)fastargs[0];
+    if (!PyDict_Check(fastargs[1])) {
+        _PyArg_BadArgument("function", 2, "dict", fastargs[1]);
+        goto exit;
+    }
+    globals = fastargs[1];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (fastargs[2]) {
+        name = fastargs[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (fastargs[3]) {
+        defaults = fastargs[3];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    closure = fastargs[4];
+skip_optional_pos:
     return_value = func_new_impl(type, code, globals, name, defaults, closure);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=a6ab29e4dd33010a input=a9049054013a1b77]*/
+/*[clinic end generated code: output=1d01072cd5620d7e input=a9049054013a1b77]*/
diff --git a/Objects/clinic/listobject.c.h b/Objects/clinic/listobject.c.h
index 447cdefbe1..7b8e2d9905 100644
--- a/Objects/clinic/listobject.c.h
+++ b/Objects/clinic/listobject.c.h
@@ -169,14 +169,35 @@ list_sort(PyListObject *self, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"key", "reverse", NULL};
-    static _PyArg_Parser _parser = {"|$Oi:sort", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sort", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *keyfunc = Py_None;
     int reverse = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &keyfunc, &reverse)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 0, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (args[0]) {
+        keyfunc = args[0];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    reverse = _PyLong_AsInt(args[1]);
+    if (reverse == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = list_sort_impl(self, keyfunc, reverse);
 
 exit:
@@ -338,4 +359,4 @@ list___reversed__(PyListObject *self, PyObject *Py_UNUSED(ignored))
 {
     return list___reversed___impl(self);
 }
-/*[clinic end generated code: output=4a835f9880a72273 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=d1d5078edb7d3cf4 input=a9049054013a1b77]*/
diff --git a/Objects/clinic/longobject.c.h b/Objects/clinic/longobject.c.h
index 67700239ff..453edba481 100644
--- a/Objects/clinic/longobject.c.h
+++ b/Objects/clinic/longobject.c.h
@@ -10,14 +10,29 @@ long_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "base", NULL};
-    static _PyArg_Parser _parser = {"|OO:int", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "int", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 0;
     PyObject *x = NULL;
     PyObject *obase = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &x, &obase)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 0, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (nargs < 1) {
+        goto skip_optional_posonly;
+    }
+    noptargs--;
+    x = fastargs[0];
+skip_optional_posonly:
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    obase = fastargs[1];
+skip_optional_pos:
     return_value = long_new_impl(type, x, obase);
 
 exit:
@@ -183,15 +198,50 @@ int_to_bytes(PyObject *self, PyObject *const *args, Py_ssize_t nargs, PyObject *
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"length", "byteorder", "signed", NULL};
-    static _PyArg_Parser _parser = {"nU|$p:to_bytes", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "to_bytes", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     Py_ssize_t length;
     PyObject *byteorder;
     int is_signed = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &length, &byteorder, &is_signed)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[0]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        length = ival;
+    }
+    if (!PyUnicode_Check(args[1])) {
+        _PyArg_BadArgument("to_bytes", 2, "str", args[1]);
         goto exit;
     }
+    if (PyUnicode_READY(args[1]) == -1) {
+        goto exit;
+    }
+    byteorder = args[1];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    is_signed = PyObject_IsTrue(args[2]);
+    if (is_signed < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
     return_value = int_to_bytes_impl(self, length, byteorder, is_signed);
 
 exit:
@@ -230,18 +280,37 @@ int_from_bytes(PyTypeObject *type, PyObject *const *args, Py_ssize_t nargs, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"bytes", "byteorder", "signed", NULL};
-    static _PyArg_Parser _parser = {"OU|$p:from_bytes", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "from_bytes", 0};
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 2;
     PyObject *bytes_obj;
     PyObject *byteorder;
     int is_signed = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &bytes_obj, &byteorder, &is_signed)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    bytes_obj = args[0];
+    if (!PyUnicode_Check(args[1])) {
+        _PyArg_BadArgument("from_bytes", 2, "str", args[1]);
+        goto exit;
+    }
+    if (PyUnicode_READY(args[1]) == -1) {
+        goto exit;
+    }
+    byteorder = args[1];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    is_signed = PyObject_IsTrue(args[2]);
+    if (is_signed < 0) {
         goto exit;
     }
+skip_optional_kwonly:
     return_value = int_from_bytes_impl(type, bytes_obj, byteorder, is_signed);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=3b91cda9d83abaa2 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=709503897c55bca1 input=a9049054013a1b77]*/
diff --git a/Objects/clinic/moduleobject.c.h b/Objects/clinic/moduleobject.c.h
index e841e76e9a..512edee72f 100644
--- a/Objects/clinic/moduleobject.c.h
+++ b/Objects/clinic/moduleobject.c.h
@@ -18,17 +18,34 @@ module___init__(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     int return_value = -1;
     static const char * const _keywords[] = {"name", "doc", NULL};
-    static _PyArg_Parser _parser = {"U|O:module", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "module", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *name;
     PyObject *doc = Py_None;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &name, &doc)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    if (!PyUnicode_Check(fastargs[0])) {
+        _PyArg_BadArgument("module", 1, "str", fastargs[0]);
+        goto exit;
+    }
+    if (PyUnicode_READY(fastargs[0]) == -1) {
+        goto exit;
+    }
+    name = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    doc = fastargs[1];
+skip_optional_pos:
     return_value = module___init___impl((PyModuleObject *)self, name, doc);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=7b1b324bf6a590d1 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=d7b7ca1237597b08 input=a9049054013a1b77]*/
diff --git a/Objects/clinic/odictobject.c.h b/Objects/clinic/odictobject.c.h
index 1aea36ec94..f43bc14ce1 100644
--- a/Objects/clinic/odictobject.c.h
+++ b/Objects/clinic/odictobject.c.h
@@ -19,14 +19,22 @@ OrderedDict_fromkeys(PyTypeObject *type, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"iterable", "value", NULL};
-    static _PyArg_Parser _parser = {"O|O:fromkeys", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "fromkeys", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *seq;
     PyObject *value = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &seq, &value)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    seq = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    value = args[1];
+skip_optional_pos:
     return_value = OrderedDict_fromkeys_impl(type, seq, value);
 
 exit:
@@ -53,14 +61,22 @@ OrderedDict_setdefault(PyODictObject *self, PyObject *const *args, Py_ssize_t na
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"key", "default", NULL};
-    static _PyArg_Parser _parser = {"O|O:setdefault", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "setdefault", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *key;
     PyObject *default_value = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &key, &default_value)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    key = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    default_value = args[1];
+skip_optional_pos:
     return_value = OrderedDict_setdefault_impl(self, key, default_value);
 
 exit:
@@ -86,13 +102,23 @@ OrderedDict_popitem(PyODictObject *self, PyObject *const *args, Py_ssize_t nargs
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"last", NULL};
-    static _PyArg_Parser _parser = {"|p:popitem", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "popitem", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int last = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &last)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    last = PyObject_IsTrue(args[0]);
+    if (last < 0) {
         goto exit;
     }
+skip_optional_pos:
     return_value = OrderedDict_popitem_impl(self, last);
 
 exit:
@@ -118,17 +144,28 @@ OrderedDict_move_to_end(PyODictObject *self, PyObject *const *args, Py_ssize_t n
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"key", "last", NULL};
-    static _PyArg_Parser _parser = {"O|p:move_to_end", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "move_to_end", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *key;
     int last = 1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &key, &last)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    key = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    last = PyObject_IsTrue(args[1]);
+    if (last < 0) {
         goto exit;
     }
+skip_optional_pos:
     return_value = OrderedDict_move_to_end_impl(self, key, last);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=f6f189e1fe032e0b input=a9049054013a1b77]*/
+/*[clinic end generated code: output=8eb1296df9142908 input=a9049054013a1b77]*/
diff --git a/Objects/clinic/structseq.c.h b/Objects/clinic/structseq.c.h
index ed6a5643f8..b3b4836543 100644
--- a/Objects/clinic/structseq.c.h
+++ b/Objects/clinic/structseq.c.h
@@ -10,17 +10,27 @@ structseq_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sequence", "dict", NULL};
-    static _PyArg_Parser _parser = {"O|O:structseq", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "structseq", 0};
+    PyObject *argsbuf[2];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *arg;
     PyObject *dict = NULL;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &arg, &dict)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 2, 0, argsbuf);
+    if (!fastargs) {
         goto exit;
     }
+    arg = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    dict = fastargs[1];
+skip_optional_pos:
     return_value = structseq_new_impl(type, arg, dict);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=cd643eb89b5d312a input=a9049054013a1b77]*/
+/*[clinic end generated code: output=ed3019acf49b656c input=a9049054013a1b77]*/
diff --git a/Objects/clinic/unicodeobject.c.h b/Objects/clinic/unicodeobject.c.h
index 3e40a62ab0..647507dea6 100644
--- a/Objects/clinic/unicodeobject.c.h
+++ b/Objects/clinic/unicodeobject.c.h
@@ -142,14 +142,51 @@ unicode_encode(PyObject *self, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"encoding", "errors", NULL};
-    static _PyArg_Parser _parser = {"|ss:encode", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "encode", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     const char *encoding = NULL;
     const char *errors = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &encoding, &errors)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        if (!PyUnicode_Check(args[0])) {
+            _PyArg_BadArgument("encode", 1, "str", args[0]);
+            goto exit;
+        }
+        Py_ssize_t encoding_length;
+        encoding = PyUnicode_AsUTF8AndSize(args[0], &encoding_length);
+        if (encoding == NULL) {
+            goto exit;
+        }
+        if (strlen(encoding) != (size_t)encoding_length) {
+            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (!PyUnicode_Check(args[1])) {
+        _PyArg_BadArgument("encode", 2, "str", args[1]);
+        goto exit;
+    }
+    Py_ssize_t errors_length;
+    errors = PyUnicode_AsUTF8AndSize(args[1], &errors_length);
+    if (errors == NULL) {
+        goto exit;
+    }
+    if (strlen(errors) != (size_t)errors_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+skip_optional_pos:
     return_value = unicode_encode_impl(self, encoding, errors);
 
 exit:
@@ -175,13 +212,28 @@ unicode_expandtabs(PyObject *self, PyObject *const *args, Py_ssize_t nargs, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"tabsize", NULL};
-    static _PyArg_Parser _parser = {"|i:expandtabs", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "expandtabs", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int tabsize = 8;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &tabsize)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    tabsize = _PyLong_AsInt(args[0]);
+    if (tabsize == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = unicode_expandtabs_impl(self, tabsize);
 
 exit:
@@ -781,14 +833,43 @@ unicode_split(PyObject *self, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sep", "maxsplit", NULL};
-    static _PyArg_Parser _parser = {"|On:split", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "split", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *sep = Py_None;
     Py_ssize_t maxsplit = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &sep, &maxsplit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        sep = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
         goto exit;
     }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        maxsplit = ival;
+    }
+skip_optional_pos:
     return_value = unicode_split_impl(self, sep, maxsplit);
 
 exit:
@@ -854,14 +935,43 @@ unicode_rsplit(PyObject *self, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sep", "maxsplit", NULL};
-    static _PyArg_Parser _parser = {"|On:rsplit", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "rsplit", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     PyObject *sep = Py_None;
     Py_ssize_t maxsplit = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &sep, &maxsplit)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[0]) {
+        sep = args[0];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = PyNumber_Index(args[1]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        maxsplit = ival;
+    }
+skip_optional_pos:
     return_value = unicode_rsplit_impl(self, sep, maxsplit);
 
 exit:
@@ -888,13 +998,28 @@ unicode_splitlines(PyObject *self, PyObject *const *args, Py_ssize_t nargs, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"keepends", NULL};
-    static _PyArg_Parser _parser = {"|i:splitlines", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "splitlines", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int keepends = 0;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &keepends)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    keepends = _PyLong_AsInt(args[0]);
+    if (keepends == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = unicode_splitlines_impl(self, keepends);
 
 exit:
@@ -1107,4 +1232,4 @@ unicode_sizeof(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
     return unicode_sizeof_impl(self);
 }
-/*[clinic end generated code: output=087ff163a10505ae input=a9049054013a1b77]*/
+/*[clinic end generated code: output=d1541724cb4a0070 input=a9049054013a1b77]*/
diff --git a/Objects/stringlib/clinic/transmogrify.h.h b/Objects/stringlib/clinic/transmogrify.h.h
index 15c43af61a..0c53a75b1b 100644
--- a/Objects/stringlib/clinic/transmogrify.h.h
+++ b/Objects/stringlib/clinic/transmogrify.h.h
@@ -21,13 +21,28 @@ stringlib_expandtabs(PyObject *self, PyObject *const *args, Py_ssize_t nargs, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"tabsize", NULL};
-    static _PyArg_Parser _parser = {"|i:expandtabs", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "expandtabs", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int tabsize = 8;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &tabsize)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    tabsize = _PyLong_AsInt(args[0]);
+    if (tabsize == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = stringlib_expandtabs_impl(self, tabsize);
 
 exit:
@@ -259,4 +274,4 @@ stringlib_zfill(PyObject *self, PyObject *arg)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=787248a980f6a00e input=a9049054013a1b77]*/
+/*[clinic end generated code: output=96cbb19b238d0e84 input=a9049054013a1b77]*/
diff --git a/PC/clinic/_testconsole.c.h b/PC/clinic/_testconsole.c.h
index 2809f2aa6e..a37d1235a0 100644
--- a/PC/clinic/_testconsole.c.h
+++ b/PC/clinic/_testconsole.c.h
@@ -22,14 +22,21 @@ _testconsole_write_input(PyObject *module, PyObject *const *args, Py_ssize_t nar
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"file", "s", NULL};
-    static _PyArg_Parser _parser = {"OS:write_input", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "write_input", 0};
+    PyObject *argsbuf[2];
     PyObject *file;
     PyBytesObject *s;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &file, &s)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    file = args[0];
+    if (!PyBytes_Check(args[1])) {
+        _PyArg_BadArgument("write_input", 2, "bytes", args[1]);
+        goto exit;
+    }
+    s = (PyBytesObject *)args[1];
     return_value = _testconsole_write_input_impl(module, file, s);
 
 exit:
@@ -57,13 +64,15 @@ _testconsole_read_output(PyObject *module, PyObject *const *args, Py_ssize_t nar
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"file", NULL};
-    static _PyArg_Parser _parser = {"O:read_output", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "read_output", 0};
+    PyObject *argsbuf[1];
     PyObject *file;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &file)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    file = args[0];
     return_value = _testconsole_read_output_impl(module, file);
 
 exit:
@@ -79,4 +88,4 @@ exit:
 #ifndef _TESTCONSOLE_READ_OUTPUT_METHODDEF
     #define _TESTCONSOLE_READ_OUTPUT_METHODDEF
 #endif /* !defined(_TESTCONSOLE_READ_OUTPUT_METHODDEF) */
-/*[clinic end generated code: output=ab9ea8e78d26288e input=a9049054013a1b77]*/
+/*[clinic end generated code: output=ef452d5fb9287fc2 input=a9049054013a1b77]*/
diff --git a/PC/clinic/winreg.c.h b/PC/clinic/winreg.c.h
index 21a9302d0a..50210250ed 100644
--- a/PC/clinic/winreg.c.h
+++ b/PC/clinic/winreg.c.h
@@ -88,15 +88,19 @@ winreg_HKEYType___exit__(PyHKEYObject *self, PyObject *const *args, Py_ssize_t n
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"exc_type", "exc_value", "traceback", NULL};
-    static _PyArg_Parser _parser = {"OOO:__exit__", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "__exit__", 0};
+    PyObject *argsbuf[3];
     PyObject *exc_type;
     PyObject *exc_value;
     PyObject *traceback;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &exc_type, &exc_value, &traceback)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    exc_type = args[0];
+    exc_value = args[1];
+    traceback = args[2];
     return_value = winreg_HKEYType___exit___impl(self, exc_type, exc_value, traceback);
 
 exit:
@@ -1117,4 +1121,4 @@ winreg_QueryReflectionKey(PyObject *module, PyObject *arg)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=bd491131d343ae7a input=a9049054013a1b77]*/
+/*[clinic end generated code: output=1204d20c543b5b4a input=a9049054013a1b77]*/
diff --git a/PC/clinic/winsound.c.h b/PC/clinic/winsound.c.h
index 86514f5cfe..b37db4c6cb 100644
--- a/PC/clinic/winsound.c.h
+++ b/PC/clinic/winsound.c.h
@@ -24,12 +24,23 @@ winsound_PlaySound(PyObject *module, PyObject *const *args, Py_ssize_t nargs, Py
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"sound", "flags", NULL};
-    static _PyArg_Parser _parser = {"Oi:PlaySound", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "PlaySound", 0};
+    PyObject *argsbuf[2];
     PyObject *sound;
     int flags;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &sound, &flags)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    sound = args[0];
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    flags = _PyLong_AsInt(args[1]);
+    if (flags == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = winsound_PlaySound_impl(module, sound, flags);
@@ -61,12 +72,31 @@ winsound_Beep(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"frequency", "duration", NULL};
-    static _PyArg_Parser _parser = {"ii:Beep", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "Beep", 0};
+    PyObject *argsbuf[2];
     int frequency;
     int duration;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &frequency, &duration)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    frequency = _PyLong_AsInt(args[0]);
+    if (frequency == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[1])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    duration = _PyLong_AsInt(args[1]);
+    if (duration == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = winsound_Beep_impl(module, frequency, duration);
@@ -94,16 +124,31 @@ winsound_MessageBeep(PyObject *module, PyObject *const *args, Py_ssize_t nargs,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"type", NULL};
-    static _PyArg_Parser _parser = {"|i:MessageBeep", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "MessageBeep", 0};
+    PyObject *argsbuf[1];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 0;
     int type = MB_OK;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &type)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 0, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    type = _PyLong_AsInt(args[0]);
+    if (type == -1 && PyErr_Occurred()) {
         goto exit;
     }
+skip_optional_pos:
     return_value = winsound_MessageBeep_impl(module, type);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=19e5f0fb15bcd5bc input=a9049054013a1b77]*/
+/*[clinic end generated code: output=28d1cd033282723d input=a9049054013a1b77]*/
diff --git a/Python/clinic/_warnings.c.h b/Python/clinic/_warnings.c.h
index d1e50de7d9..67ab0e3d9d 100644
--- a/Python/clinic/_warnings.c.h
+++ b/Python/clinic/_warnings.c.h
@@ -20,19 +20,55 @@ warnings_warn(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"message", "category", "stacklevel", "source", NULL};
-    static _PyArg_Parser _parser = {"O|OnO:warn", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "warn", 0};
+    PyObject *argsbuf[4];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *message;
     PyObject *category = Py_None;
     Py_ssize_t stacklevel = 1;
     PyObject *source = Py_None;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &message, &category, &stacklevel, &source)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 4, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    message = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[1]) {
+        category = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[2]) {
+        if (PyFloat_Check(args[2])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        {
+            Py_ssize_t ival = -1;
+            PyObject *iobj = PyNumber_Index(args[2]);
+            if (iobj != NULL) {
+                ival = PyLong_AsSsize_t(iobj);
+                Py_DECREF(iobj);
+            }
+            if (ival == -1 && PyErr_Occurred()) {
+                goto exit;
+            }
+            stacklevel = ival;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    source = args[3];
+skip_optional_pos:
     return_value = warnings_warn_impl(module, message, category, stacklevel, source);
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=a4fbe6e2d1cc2091 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b7bb54c73b5433ec input=a9049054013a1b77]*/
diff --git a/Python/clinic/bltinmodule.c.h b/Python/clinic/bltinmodule.c.h
index df9970942b..0ed11bceeb 100644
--- a/Python/clinic/bltinmodule.c.h
+++ b/Python/clinic/bltinmodule.c.h
@@ -180,7 +180,9 @@ builtin_compile(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"source", "filename", "mode", "flags", "dont_inherit", "optimize", "feature_version", NULL};
-    static _PyArg_Parser _parser = {"OO&s|iiii:compile", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "compile", 0};
+    PyObject *argsbuf[7];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
     PyObject *source;
     PyObject *filename;
     const char *mode;
@@ -189,10 +191,82 @@ builtin_compile(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
     int optimize = -1;
     int feature_version = -1;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &source, PyUnicode_FSDecoder, &filename, &mode, &flags, &dont_inherit, &optimize, &feature_version)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 7, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    source = args[0];
+    if (!PyUnicode_FSDecoder(args[1], &filename)) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[2])) {
+        _PyArg_BadArgument("compile", 3, "str", args[2]);
+        goto exit;
+    }
+    Py_ssize_t mode_length;
+    mode = PyUnicode_AsUTF8AndSize(args[2], &mode_length);
+    if (mode == NULL) {
+        goto exit;
+    }
+    if (strlen(mode) != (size_t)mode_length) {
+        PyErr_SetString(PyExc_ValueError, "embedded null character");
+        goto exit;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[3]) {
+        if (PyFloat_Check(args[3])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        flags = _PyLong_AsInt(args[3]);
+        if (flags == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[4]) {
+        if (PyFloat_Check(args[4])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        dont_inherit = _PyLong_AsInt(args[4]);
+        if (dont_inherit == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[5]) {
+        if (PyFloat_Check(args[5])) {
+            PyErr_SetString(PyExc_TypeError,
+                            "integer argument expected, got float" );
+            goto exit;
+        }
+        optimize = _PyLong_AsInt(args[5]);
+        if (optimize == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (PyFloat_Check(args[6])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    feature_version = _PyLong_AsInt(args[6]);
+    if (feature_version == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_pos:
     return_value = builtin_compile_impl(module, source, filename, mode, flags, dont_inherit, optimize, feature_version);
 
 exit:
@@ -637,14 +711,22 @@ builtin_round(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObjec
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"number", "ndigits", NULL};
-    static _PyArg_Parser _parser = {"O|O:round", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "round", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *number;
     PyObject *ndigits = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &number, &ndigits)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    number = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    ndigits = args[1];
+skip_optional_pos:
     return_value = builtin_round_impl(module, number, ndigits);
 
 exit:
@@ -672,14 +754,22 @@ builtin_sum(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"", "start", NULL};
-    static _PyArg_Parser _parser = {"O|O:sum", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "sum", 0};
+    PyObject *argsbuf[2];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *iterable;
     PyObject *start = NULL;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &iterable, &start)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 2, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
+    iterable = args[0];
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    start = args[1];
+skip_optional_pos:
     return_value = builtin_sum_impl(module, iterable, start);
 
 exit:
@@ -755,4 +845,4 @@ builtin_issubclass(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=00b97a48ea49eaf2 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=3f690311ac556c31 input=a9049054013a1b77]*/
diff --git a/Python/clinic/import.c.h b/Python/clinic/import.c.h
index 9ee20fbe50..05e3106bb3 100644
--- a/Python/clinic/import.c.h
+++ b/Python/clinic/import.c.h
@@ -411,12 +411,29 @@ _imp_source_hash(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyOb
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"key", "source", NULL};
-    static _PyArg_Parser _parser = {"ly*:source_hash", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "source_hash", 0};
+    PyObject *argsbuf[2];
     long key;
     Py_buffer source = {NULL, NULL};
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &key, &source)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    key = PyLong_AsLong(args[0]);
+    if (key == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyObject_GetBuffer(args[1], &source, PyBUF_SIMPLE) != 0) {
+        goto exit;
+    }
+    if (!PyBuffer_IsContiguous(&source, 'C')) {
+        _PyArg_BadArgument("source_hash", 2, "contiguous buffer", args[1]);
         goto exit;
     }
     return_value = _imp_source_hash_impl(module, key, &source);
@@ -437,4 +454,4 @@ exit:
 #ifndef _IMP_EXEC_DYNAMIC_METHODDEF
     #define _IMP_EXEC_DYNAMIC_METHODDEF
 #endif /* !defined(_IMP_EXEC_DYNAMIC_METHODDEF) */
-/*[clinic end generated code: output=2409b8feeafe7c4b input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b51244770fdcf4b8 input=a9049054013a1b77]*/
diff --git a/Python/clinic/sysmodule.c.h b/Python/clinic/sysmodule.c.h
index fc9794bf25..c70b721983 100644
--- a/Python/clinic/sysmodule.c.h
+++ b/Python/clinic/sysmodule.c.h
@@ -410,11 +410,21 @@ sys_set_coroutine_origin_tracking_depth(PyObject *module, PyObject *const *args,
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"depth", NULL};
-    static _PyArg_Parser _parser = {"i:set_coroutine_origin_tracking_depth", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "set_coroutine_origin_tracking_depth", 0};
+    PyObject *argsbuf[1];
     int depth;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &depth)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (PyFloat_Check(args[0])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    depth = _PyLong_AsInt(args[0]);
+    if (depth == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = sys_set_coroutine_origin_tracking_depth_impl(module, depth);
@@ -1050,4 +1060,4 @@ sys_getandroidapilevel(PyObject *module, PyObject *Py_UNUSED(ignored))
 #ifndef SYS_GETANDROIDAPILEVEL_METHODDEF
     #define SYS_GETANDROIDAPILEVEL_METHODDEF
 #endif /* !defined(SYS_GETANDROIDAPILEVEL_METHODDEF) */
-/*[clinic end generated code: output=109787af3401cd27 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=3ba4c194d00f1866 input=a9049054013a1b77]*/
diff --git a/Python/clinic/traceback.c.h b/Python/clinic/traceback.c.h
index d9daccbbb7..2815f65d3d 100644
--- a/Python/clinic/traceback.c.h
+++ b/Python/clinic/traceback.c.h
@@ -17,14 +17,41 @@ tb_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"tb_next", "tb_frame", "tb_lasti", "tb_lineno", NULL};
-    static _PyArg_Parser _parser = {"OO!ii:TracebackType", _keywords, 0};
+    static _PyArg_Parser _parser = {NULL, _keywords, "TracebackType", 0};
+    PyObject *argsbuf[4];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     PyObject *tb_next;
     PyFrameObject *tb_frame;
     int tb_lasti;
     int tb_lineno;
 
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &tb_next, &PyFrame_Type, &tb_frame, &tb_lasti, &tb_lineno)) {
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 4, 4, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    tb_next = fastargs[0];
+    if (!PyObject_TypeCheck(fastargs[1], &PyFrame_Type)) {
+        _PyArg_BadArgument("TracebackType", 2, (&PyFrame_Type)->tp_name, fastargs[1]);
+        goto exit;
+    }
+    tb_frame = (PyFrameObject *)fastargs[1];
+    if (PyFloat_Check(fastargs[2])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    tb_lasti = _PyLong_AsInt(fastargs[2]);
+    if (tb_lasti == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    if (PyFloat_Check(fastargs[3])) {
+        PyErr_SetString(PyExc_TypeError,
+                        "integer argument expected, got float" );
+        goto exit;
+    }
+    tb_lineno = _PyLong_AsInt(fastargs[3]);
+    if (tb_lineno == -1 && PyErr_Occurred()) {
         goto exit;
     }
     return_value = tb_new_impl(type, tb_next, tb_frame, tb_lasti, tb_lineno);
@@ -32,4 +59,4 @@ tb_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=0133130d7d19556f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=7e4c0e252d0973b0 input=a9049054013a1b77]*/
diff --git a/Python/getargs.c b/Python/getargs.c
index 05ebe9c45b..693a29cced 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -1905,24 +1905,11 @@ parser_init(struct _PyArg_Parser *parser)
     int i, len, min, max, nkw;
     PyObject *kwtuple;
 
-    assert(parser->format != NULL);
     assert(parser->keywords != NULL);
     if (parser->kwtuple != NULL) {
         return 1;
     }
 
-    /* grab the function name or custom error msg first (mutually exclusive) */
-    parser->fname = strchr(parser->format, ':');
-    if (parser->fname) {
-        parser->fname++;
-        parser->custom_msg = NULL;
-    }
-    else {
-        parser->custom_msg = strchr(parser->format,';');
-        if (parser->custom_msg)
-            parser->custom_msg++;
-    }
-
     keywords = parser->keywords;
     /* scan keywords and count the number of positional-only parameters */
     for (i = 0; keywords[i] && !*keywords[i]; i++) {
@@ -1938,60 +1925,74 @@ parser_init(struct _PyArg_Parser *parser)
     }
     len = i;
 
-    min = max = INT_MAX;
     format = parser->format;
-    for (i = 0; i < len; i++) {
-        if (*format == '|') {
-            if (min != INT_MAX) {
-                PyErr_SetString(PyExc_SystemError,
-                                "Invalid format string (| specified twice)");
-                return 0;
+    if (format) {
+        /* grab the function name or custom error msg first (mutually exclusive) */
+        parser->fname = strchr(parser->format, ':');
+        if (parser->fname) {
+            parser->fname++;
+            parser->custom_msg = NULL;
+        }
+        else {
+            parser->custom_msg = strchr(parser->format,';');
+            if (parser->custom_msg)
+                parser->custom_msg++;
+        }
+
+        min = max = INT_MAX;
+        for (i = 0; i < len; i++) {
+            if (*format == '|') {
+                if (min != INT_MAX) {
+                    PyErr_SetString(PyExc_SystemError,
+                                    "Invalid format string (| specified twice)");
+                    return 0;
+                }
+                if (max != INT_MAX) {
+                    PyErr_SetString(PyExc_SystemError,
+                                    "Invalid format string ($ before |)");
+                    return 0;
+                }
+                min = i;
+                format++;
             }
-            if (max != INT_MAX) {
-                PyErr_SetString(PyExc_SystemError,
-                                "Invalid format string ($ before |)");
-                return 0;
+            if (*format == '$') {
+                if (max != INT_MAX) {
+                    PyErr_SetString(PyExc_SystemError,
+                                    "Invalid format string ($ specified twice)");
+                    return 0;
+                }
+                if (i < parser->pos) {
+                    PyErr_SetString(PyExc_SystemError,
+                                    "Empty parameter name after $");
+                    return 0;
+                }
+                max = i;
+                format++;
             }
-            min = i;
-            format++;
-        }
-        if (*format == '$') {
-            if (max != INT_MAX) {
-                PyErr_SetString(PyExc_SystemError,
-                                "Invalid format string ($ specified twice)");
+            if (IS_END_OF_FORMAT(*format)) {
+                PyErr_Format(PyExc_SystemError,
+                            "More keyword list entries (%d) than "
+                            "format specifiers (%d)", len, i);
                 return 0;
             }
-            if (i < parser->pos) {
-                PyErr_SetString(PyExc_SystemError,
-                                "Empty parameter name after $");
+
+            msg = skipitem(&format, NULL, 0);
+            if (msg) {
+                PyErr_Format(PyExc_SystemError, "%s: '%s'", msg,
+                            format);
                 return 0;
             }
-            max = i;
-            format++;
-        }
-        if (IS_END_OF_FORMAT(*format)) {
-            PyErr_Format(PyExc_SystemError,
-                         "More keyword list entries (%d) than "
-                         "format specifiers (%d)", len, i);
-            return 0;
         }
+        parser->min = Py_MIN(min, len);
+        parser->max = Py_MIN(max, len);
 
-        msg = skipitem(&format, NULL, 0);
-        if (msg) {
-            PyErr_Format(PyExc_SystemError, "%s: '%s'", msg,
-                         format);
+        if (!IS_END_OF_FORMAT(*format) && (*format != '|') && (*format != '$')) {
+            PyErr_Format(PyExc_SystemError,
+                "more argument specifiers than keyword list entries "
+                "(remaining format:'%s')", format);
             return 0;
         }
     }
-    parser->min = Py_MIN(min, len);
-    parser->max = Py_MIN(max, len);
-
-    if (!IS_END_OF_FORMAT(*format) && (*format != '|') && (*format != '$')) {
-        PyErr_Format(PyExc_SystemError,
-            "more argument specifiers than keyword list entries "
-            "(remaining format:'%s')", format);
-        return 0;
-    }
 
     nkw = len - parser->pos;
     kwtuple = PyTuple_New(nkw);
@@ -2313,6 +2314,215 @@ vgetargskeywordsfast(PyObject *args, PyObject *keywords,
 }
 
 
+#undef _PyArg_UnpackKeywords
+
+PyObject * const *
+_PyArg_UnpackKeywords(PyObject *const *args, Py_ssize_t nargs,
+                      PyObject *kwargs, PyObject *kwnames,
+                      struct _PyArg_Parser *parser,
+                      int minpos, int maxpos, int minkw,
+                      PyObject **buf)
+{
+    PyObject *kwtuple;
+    PyObject *keyword;
+    int i, posonly, minposonly, maxargs;
+    int reqlimit = minkw ? maxpos + minkw : minpos;
+    Py_ssize_t nkwargs;
+    PyObject *current_arg;
+    PyObject * const *kwstack = NULL;
+
+    assert(kwargs == NULL || PyDict_Check(kwargs));
+    assert(kwargs == NULL || kwnames == NULL);
+
+    if (parser == NULL) {
+        PyErr_BadInternalCall();
+        return NULL;
+    }
+
+    if (kwnames != NULL && !PyTuple_Check(kwnames)) {
+        PyErr_BadInternalCall();
+        return NULL;
+    }
+
+    if (args == NULL && nargs == 0) {
+        args = buf;
+    }
+
+    if (!parser_init(parser)) {
+        return NULL;
+    }
+
+    kwtuple = parser->kwtuple;
+    posonly = parser->pos;
+    minposonly = Py_MIN(posonly, minpos);
+    maxargs = posonly + (int)PyTuple_GET_SIZE(kwtuple);
+
+    if (kwargs != NULL) {
+        nkwargs = PyDict_GET_SIZE(kwargs);
+    }
+    else if (kwnames != NULL) {
+        nkwargs = PyTuple_GET_SIZE(kwnames);
+        kwstack = args + nargs;
+    }
+    else {
+        nkwargs = 0;
+    }
+    if (nkwargs == 0 && minkw == 0 && minpos <= nargs && nargs <= maxpos) {
+        /* Fast path. */
+        return args;
+    }
+    if (nargs + nkwargs > maxargs) {
+        /* Adding "keyword" (when nargs == 0) prevents producing wrong error
+           messages in some special cases (see bpo-31229). */
+        PyErr_Format(PyExc_TypeError,
+                     "%.200s%s takes at most %d %sargument%s (%zd given)",
+                     (parser->fname == NULL) ? "function" : parser->fname,
+                     (parser->fname == NULL) ? "" : "()",
+                     maxargs,
+                     (nargs == 0) ? "keyword " : "",
+                     (maxargs == 1) ? "" : "s",
+                     nargs + nkwargs);
+        return NULL;
+    }
+    if (nargs > maxpos) {
+        if (maxpos == 0) {
+            PyErr_Format(PyExc_TypeError,
+                         "%.200s%s takes no positional arguments",
+                         (parser->fname == NULL) ? "function" : parser->fname,
+                         (parser->fname == NULL) ? "" : "()");
+        }
+        else {
+            PyErr_Format(PyExc_TypeError,
+                         "%.200s%s takes %s %d positional argument%s (%zd given)",
+                         (parser->fname == NULL) ? "function" : parser->fname,
+                         (parser->fname == NULL) ? "" : "()",
+                         (minpos < maxpos) ? "at most" : "exactly",
+                         maxpos,
+                         (maxpos == 1) ? "" : "s",
+                         nargs);
+        }
+        return NULL;
+    }
+    if (nargs < minposonly) {
+        PyErr_Format(PyExc_TypeError,
+                     "%.200s%s takes %s %d positional argument%s"
+                     " (%zd given)",
+                     (parser->fname == NULL) ? "function" : parser->fname,
+                     (parser->fname == NULL) ? "" : "()",
+                     minposonly < maxpos ? "at least" : "exactly",
+                     minposonly,
+                     minposonly == 1 ? "" : "s",
+                     nargs);
+        return NULL;
+    }
+
+    /* copy tuple args */
+    for (i = 0; i < nargs; i++) {
+        buf[i] = args[i];
+    }
+
+    /* copy keyword args using kwtuple to drive process */
+    for (i = Py_MAX(nargs, posonly); i < maxargs; i++) {
+        if (nkwargs) {
+            keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
+            if (kwargs != NULL) {
+                current_arg = PyDict_GetItemWithError(kwargs, keyword);
+                if (!current_arg && PyErr_Occurred()) {
+                    return NULL;
+                }
+            }
+            else {
+                current_arg = find_keyword(kwnames, kwstack, keyword);
+            }
+        }
+        else if (i >= reqlimit) {
+            break;
+        }
+        else {
+            current_arg = NULL;
+        }
+
+        buf[i] = current_arg;
+
+        if (current_arg) {
+            --nkwargs;
+        }
+        else if (i < minpos || (maxpos <= i && i < reqlimit)) {
+            /* Less arguments than required */
+            keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
+            PyErr_Format(PyExc_TypeError,  "%.200s%s missing required "
+                         "argument '%U' (pos %d)",
+                         (parser->fname == NULL) ? "function" : parser->fname,
+                         (parser->fname == NULL) ? "" : "()",
+                         keyword, i+1);
+            return NULL;
+        }
+    }
+
+    if (nkwargs > 0) {
+        Py_ssize_t j;
+        /* make sure there are no arguments given by name and position */
+        for (i = posonly; i < nargs; i++) {
+            keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
+            if (kwargs != NULL) {
+                current_arg = PyDict_GetItemWithError(kwargs, keyword);
+                if (!current_arg && PyErr_Occurred()) {
+                    return NULL;
+                }
+            }
+            else {
+                current_arg = find_keyword(kwnames, kwstack, keyword);
+            }
+            if (current_arg) {
+                /* arg present in tuple and in dict */
+                PyErr_Format(PyExc_TypeError,
+                             "argument for %.200s%s given by name ('%U') "
+                             "and position (%d)",
+                             (parser->fname == NULL) ? "function" : parser->fname,
+                             (parser->fname == NULL) ? "" : "()",
+                             keyword, i+1);
+                return NULL;
+            }
+        }
+        /* make sure there are no extraneous keyword arguments */
+        j = 0;
+        while (1) {
+            int match;
+            if (kwargs != NULL) {
+                if (!PyDict_Next(kwargs, &j, &keyword, NULL))
+                    break;
+            }
+            else {
+                if (j >= PyTuple_GET_SIZE(kwnames))
+                    break;
+                keyword = PyTuple_GET_ITEM(kwnames, j);
+                j++;
+            }
+
+            if (!PyUnicode_Check(keyword)) {
+                PyErr_SetString(PyExc_TypeError,
+                                "keywords must be strings");
+                return NULL;
+            }
+            match = PySequence_Contains(kwtuple, keyword);
+            if (match <= 0) {
+                if (!match) {
+                    PyErr_Format(PyExc_TypeError,
+                                 "'%U' is an invalid keyword "
+                                 "argument for %.200s%s",
+                                 keyword,
+                                 (parser->fname == NULL) ? "this function" : parser->fname,
+                                 (parser->fname == NULL) ? "" : "()");
+                }
+                return NULL;
+            }
+        }
+    }
+
+    return buf;
+}
+
+
 static const char *
 skipitem(const char **p_format, va_list *p_va, int flags)
 {
diff --git a/Tools/clinic/clinic.py b/Tools/clinic/clinic.py
index 0e7ce965b0..cb2ded4649 100755
--- a/Tools/clinic/clinic.py
+++ b/Tools/clinic/clinic.py
@@ -645,10 +645,21 @@ class CLanguage(Language):
         default_return_converter = (not f.return_converter or
             f.return_converter.type == 'PyObject *')
 
-        positional = parameters and parameters[-1].is_positional_only()
-
         new_or_init = f.kind in (METHOD_NEW, METHOD_INIT)
 
+        pos_only = min_pos = max_pos = min_kw_only = 0
+        for i, p in enumerate(parameters, 1):
+            if p.is_keyword_only():
+                assert not p.is_positional_only()
+                if not p.is_optional():
+                    min_kw_only = i - max_pos
+            else:
+                max_pos = i
+                if p.is_positional_only():
+                    pos_only = i
+                if not p.is_optional():
+                    min_pos = i
+
         meth_o = (len(parameters) == 1 and
               parameters[0].is_positional_only() and
               not converters[0].is_optional() and
@@ -712,16 +723,19 @@ class CLanguage(Language):
         # parser_body_fields remembers the fields passed in to the
         # previous call to parser_body. this is used for an awful hack.
         parser_body_fields = ()
-        def parser_body(prototype, *fields):
-            nonlocal parser_body_fields
+        parser_body_declarations = ''
+        def parser_body(prototype, *fields, declarations=''):
+            nonlocal parser_body_fields, parser_body_declarations
             add, output = text_accumulator()
             add(prototype)
             parser_body_fields = fields
+            parser_body_declarations = declarations
 
             fields = list(fields)
             fields.insert(0, normalize_snippet("""
                 {{
                     {return_value_declaration}
+                    {parser_declarations}
                     {declarations}
                     {initializers}
                 """) + "\n")
@@ -739,13 +753,7 @@ class CLanguage(Language):
             for field in fields:
                 add('\n')
                 add(field)
-            return output()
-
-        def insert_keywords(s):
-            return linear_format(s, declarations=
-                'static const char * const _keywords[] = {{{keywords}, NULL}};\n'
-                'static _PyArg_Parser _parser = {{"{format_units}:{name}", _keywords, 0}};\n'
-                '{declarations}')
+            return linear_format(output(), parser_declarations=declarations)
 
         if not parameters:
             # no parameters, METH_NOARGS
@@ -818,7 +826,7 @@ class CLanguage(Language):
 
             parser_definition = parser_body(parser_prototype, '    {option_group_parsing}')
 
-        elif positional:
+        elif pos_only == len(parameters):
             if not new_or_init:
                 # positional-only, but no option groups
                 # we only need one call to _PyArg_ParseStack
@@ -836,15 +844,19 @@ class CLanguage(Language):
                 nargs = 'PyTuple_GET_SIZE(args)'
                 argname_fmt = 'PyTuple_GET_ITEM(args, %d)'
 
-            parser_code = []
+            parser_code = [normalize_snippet("""
+                if (!_PyArg_CheckPositional("{name}", %s, %d, %d)) {{
+                    goto exit;
+                }}
+                """ % (nargs, min_pos, max_pos), indent=4)]
             has_optional = False
-            for i, converter in enumerate(converters):
-                parsearg = converter.parse_arg(argname_fmt % i, i + 1)
+            for i, p in enumerate(parameters):
+                parsearg = p.converter.parse_arg(argname_fmt % i, i + 1)
                 if parsearg is None:
-                    #print('Cannot convert %s %r for %s' % (converter.__class__.__name__, converter.format_unit, converter.name), file=sys.stderr)
+                    #print('Cannot convert %s %r for %s' % (p.converter.__class__.__name__, p.converter.format_unit, p.converter.name), file=sys.stderr)
                     parser_code = None
                     break
-                if has_optional or converter.default is not unspecified:
+                if has_optional or p.is_optional():
                     has_optional = True
                     parser_code.append(normalize_snippet("""
                         if (%s < %d) {{
@@ -854,11 +866,6 @@ class CLanguage(Language):
                 parser_code.append(normalize_snippet(parsearg, indent=4))
 
             if parser_code is not None:
-                parser_code.insert(0, normalize_snippet("""
-                    if (!_PyArg_CheckPositional("{name}", %s, {unpack_min}, {unpack_max})) {{
-                        goto exit;
-                    }}
-                    """ % nargs, indent=4))
                 if has_optional:
                     parser_code.append("skip_optional:")
             else:
@@ -878,33 +885,122 @@ class CLanguage(Language):
                         """, indent=4)]
             parser_definition = parser_body(parser_prototype, *parser_code)
 
-        elif not new_or_init:
-            flags = "METH_FASTCALL|METH_KEYWORDS"
-
-            parser_prototype = parser_prototype_fastcall_keywords
-
-            body = normalize_snippet("""
-                if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-                    {parse_arguments})) {{
-                    goto exit;
-                }}
-                """, indent=4)
-            parser_definition = parser_body(parser_prototype, body)
-            parser_definition = insert_keywords(parser_definition)
         else:
-            # positional-or-keyword arguments
-            flags = "METH_VARARGS|METH_KEYWORDS"
+            has_optional_kw = (max(pos_only, min_pos) + min_kw_only < len(converters))
+            if not new_or_init:
+                flags = "METH_FASTCALL|METH_KEYWORDS"
+                parser_prototype = parser_prototype_fastcall_keywords
+                argname_fmt = 'args[%d]'
+                declarations = normalize_snippet("""
+                    static const char * const _keywords[] = {{{keywords}, NULL}};
+                    static _PyArg_Parser _parser = {{NULL, _keywords, "{name}", 0}};
+                    PyObject *argsbuf[%s];
+                    """ % len(converters))
+                if has_optional_kw:
+                    declarations += "\nPy_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - %d;" % (min_pos + min_kw_only)
+                parser_code = [normalize_snippet("""
+                    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, %d, %d, %d, argsbuf);
+                    if (!args) {{
+                        goto exit;
+                    }}
+                    """ % (min_pos, max_pos, min_kw_only), indent=4)]
+            else:
+                # positional-or-keyword arguments
+                flags = "METH_VARARGS|METH_KEYWORDS"
+                parser_prototype = parser_prototype_keyword
+                argname_fmt = 'fastargs[%d]'
+                declarations = normalize_snippet("""
+                    static const char * const _keywords[] = {{{keywords}, NULL}};
+                    static _PyArg_Parser _parser = {{NULL, _keywords, "{name}", 0}};
+                    PyObject *argsbuf[%s];
+                    PyObject * const *fastargs;
+                    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+                    """ % len(converters))
+                if has_optional_kw:
+                    declarations += "\nPy_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - %d;" % (min_pos + min_kw_only)
+                parser_code = [normalize_snippet("""
+                    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, %d, %d, %d, argsbuf);
+                    if (!fastargs) {{
+                        goto exit;
+                    }}
+                    """ % (min_pos, max_pos, min_kw_only), indent=4)]
 
-            parser_prototype = parser_prototype_keyword
+            add_label = None
+            for i, p in enumerate(parameters):
+                parsearg = p.converter.parse_arg(argname_fmt % i, i + 1)
+                if parsearg is None:
+                    #print('Cannot convert %s %r for %s' % (p.converter.__class__.__name__, p.converter.format_unit, p.converter.name), file=sys.stderr)
+                    parser_code = None
+                    break
+                if add_label and (i == pos_only or i == max_pos):
+                    parser_code.append("%s:" % add_label)
+                    add_label = None
+                if not p.is_optional():
+                    parser_code.append(normalize_snippet(parsearg, indent=4))
+                elif i < pos_only:
+                    add_label = 'skip_optional_posonly'
+                    parser_code.append(normalize_snippet("""
+                        if (nargs < %d) {{
+                            goto %s;
+                        }}
+                        """ % (i + 1, add_label), indent=4))
+                    if has_optional_kw:
+                        parser_code.append(normalize_snippet("""
+                            noptargs--;
+                            """, indent=4))
+                    parser_code.append(normalize_snippet(parsearg, indent=4))
+                else:
+                    if i < max_pos:
+                        label = 'skip_optional_pos'
+                        first_opt = max(min_pos, pos_only)
+                    else:
+                        label = 'skip_optional_kwonly'
+                        first_opt = max_pos + min_kw_only
+                    if i == first_opt:
+                        add_label = label
+                        parser_code.append(normalize_snippet("""
+                            if (!noptargs) {{
+                                goto %s;
+                            }}
+                            """ % add_label, indent=4))
+                    if i + 1 == len(parameters):
+                        parser_code.append(normalize_snippet(parsearg, indent=4))
+                    else:
+                        add_label = label
+                        parser_code.append(normalize_snippet("""
+                            if (%s) {{
+                            """ % (argname_fmt % i), indent=4))
+                        parser_code.append(normalize_snippet(parsearg, indent=8))
+                        parser_code.append(normalize_snippet("""
+                                if (!--noptargs) {{
+                                    goto %s;
+                                }}
+                            }}
+                            """ % add_label, indent=4))
 
-            body = normalize_snippet("""
-                if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-                    {parse_arguments})) {{
-                    goto exit;
-                }}
-                """, indent=4)
-            parser_definition = parser_body(parser_prototype, body)
-            parser_definition = insert_keywords(parser_definition)
+            if parser_code is not None:
+                if add_label:
+                    parser_code.append("%s:" % add_label)
+            else:
+                declarations = (
+                    'static const char * const _keywords[] = {{{keywords}, NULL}};\n'
+                    'static _PyArg_Parser _parser = {{"{format_units}:{name}", _keywords, 0}};')
+                if not new_or_init:
+                    parser_code = [normalize_snippet("""
+                        if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
+                            {parse_arguments})) {{
+                            goto exit;
+                        }}
+                        """, indent=4)]
+                else:
+                    parser_code = [normalize_snippet("""
+                        if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
+                            {parse_arguments})) {{
+                            goto exit;
+                        }}
+                        """, indent=4)]
+            parser_definition = parser_body(parser_prototype, *parser_code,
+                                            declarations=declarations)
 
 
         if new_or_init:
@@ -938,9 +1034,8 @@ class CLanguage(Language):
                         }}
                         """, indent=4))
 
-            parser_definition = parser_body(parser_prototype, *fields)
-            if parses_keywords:
-                parser_definition = insert_keywords(parser_definition)
+            parser_definition = parser_body(parser_prototype, *fields,
+                                            declarations=parser_body_declarations)
 
 
         if flags in ('METH_NOARGS', 'METH_O', 'METH_VARARGS'):
@@ -2176,6 +2271,9 @@ class Parameter:
     def is_positional_only(self):
         return self.kind == inspect.Parameter.POSITIONAL_ONLY
 
+    def is_optional(self):
+        return (self.default is not unspecified)
+
     def copy(self, **overrides):
         kwargs = {
             'name': self.name, 'kind': self.kind, 'default':self.default,