diff --git a/Modules/clinic/_testclinic.c.h b/Modules/clinic/_testclinic.c.h
index b2db377023f2e6..c6133a3a2e6410 100644
--- a/Modules/clinic/_testclinic.c.h
+++ b/Modules/clinic/_testclinic.c.h
@@ -3733,7 +3733,7 @@ _testclinic_TestClass_defclass_varpos(PyObject *self, PyTypeObject *cls, PyObjec
         .kwtuple = KWTUPLE,
     };
     #undef KWTUPLE
-    PyObject *argsbuf[0];
+    PyObject *argsbuf[1];
     PyObject * const *fastargs;
     PyObject *__clinic_args = NULL;
 
@@ -3809,4 +3809,4 @@ _testclinic_TestClass_defclass_posonly_varpos(PyObject *self, PyTypeObject *cls,
 
     return return_value;
 }
-/*[clinic end generated code: output=fa10ab215bdd6259 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=e4717fe7fdaf5cf3 input=a9049054013a1b77]*/
diff --git a/Tools/clinic/libclinic/parse_args.py b/Tools/clinic/libclinic/parse_args.py
index 650bed5f2391de..edf13e9f958421 100644
--- a/Tools/clinic/libclinic/parse_args.py
+++ b/Tools/clinic/libclinic/parse_args.py
@@ -657,7 +657,7 @@ def parse_general(self, clang: CLanguage) -> None:
                 self.flags = "METH_FASTCALL|METH_KEYWORDS"
                 self.parser_prototype = PARSER_PROTOTYPE_FASTCALL_KEYWORDS
                 self.declarations = declare_parser(self.func, codegen=self.codegen)
-                self.declarations += "\nPyObject *argsbuf[%s];" % len(self.converters)
+                self.declarations += "\nPyObject *argsbuf[%s];" % (len(self.converters) or 1)
                 if self.varpos:
                     self.declarations += "\nPyObject * const *fastargs;"
                     argsname = 'fastargs'
@@ -675,7 +675,7 @@ def parse_general(self, clang: CLanguage) -> None:
                 argsname = 'fastargs'
                 argname_fmt = 'fastargs[%d]'
                 self.declarations = declare_parser(self.func, codegen=self.codegen)
-                self.declarations += "\nPyObject *argsbuf[%s];" % len(self.converters)
+                self.declarations += "\nPyObject *argsbuf[%s];" % (len(self.converters) or 1)
                 self.declarations += "\nPyObject * const *fastargs;"
                 self.declarations += "\nPy_ssize_t nargs = PyTuple_GET_SIZE(args);"
                 if has_optional_kw: