2 files changed, 78 insertions, 0 deletions
diff --git a/Modules/_testcapi/parts.h b/Modules/_testcapi/parts.h
index e6d2ed2..4b672c9 100644
--- a/Modules/_testcapi/parts.h
+++ b/Modules/_testcapi/parts.h
@@ -1,4 +1,5 @@
 #include "Python.h"
 
 int _PyTestCapi_Init_Vectorcall(PyObject *module);
+int _PyTestCapi_Init_VectorcallLimited(PyObject *module);
 int _PyTestCapi_Init_Heaptype(PyObject *module);
diff --git a/Modules/_testcapi/vectorcall_limited.c b/Modules/_testcapi/vectorcall_limited.c
new file mode 100644
index 0000000..63ea3b3
--- /dev/null
+++ b/Modules/_testcapi/vectorcall_limited.c
@@ -0,0 +1,77 @@
+#define Py_LIMITED_API 0x030c0000 // 3.12
+#include "parts.h"
+#include "structmember.h"         // PyMemberDef
+
+/* Test Vectorcall in the limited API */
+
+static PyObject *
+LimitedVectorCallClass_tpcall(PyObject *self, PyObject *args, PyObject *kwargs) {
+    return PyUnicode_FromString("tp_call called");
+}
+
+static PyObject *
+LimitedVectorCallClass_vectorcall(PyObject *callable,
+                            PyObject *const *args,
+                            size_t nargsf,
+                            PyObject *kwnames) {
+    return PyUnicode_FromString("vectorcall called");
+}
+
+static PyObject *
+LimitedVectorCallClass_new(PyTypeObject *tp, PyTypeObject *a, PyTypeObject *kw)
+{
+    PyObject *self = ((allocfunc)PyType_GetSlot(tp, Py_tp_alloc))(tp, 0);
+    if (!self) {
+        return NULL;
+    }
+    *(vectorcallfunc*)((char*)self + sizeof(PyObject)) = (
+        LimitedVectorCallClass_vectorcall);
+    return self;
+}
+
+static PyMemberDef LimitedVectorCallClass_members[] = {
+    {"__vectorcalloffset__", T_PYSSIZET, sizeof(PyObject), READONLY},
+    {NULL}
+};
+
+static PyType_Slot LimitedVectorallClass_slots[] = {
+    {Py_tp_new, LimitedVectorCallClass_new},
+    {Py_tp_call, LimitedVectorCallClass_tpcall},
+    {Py_tp_members, LimitedVectorCallClass_members},
+    {0},
+};
+
+static PyType_Spec LimitedVectorCallClass_spec = {
+    .name = "_testcapi.LimitedVectorCallClass",
+    .basicsize = (int)(sizeof(PyObject) + sizeof(vectorcallfunc)),
+    .flags = Py_TPFLAGS_DEFAULT
+        | Py_TPFLAGS_HAVE_VECTORCALL
+        | Py_TPFLAGS_BASETYPE,
+    .slots = LimitedVectorallClass_slots,
+};
+
+static PyMethodDef TestMethods[] = {
+    /* Add module methods here.
+     * (Empty list left here as template/example, since using
+     * PyModule_AddFunctions isn't very common.)
+     */
+    {NULL},
+};
+
+int
+_PyTestCapi_Init_VectorcallLimited(PyObject *m) {
+    if (PyModule_AddFunctions(m, TestMethods) < 0) {
+        return -1;
+    }
+
+    PyObject *LimitedVectorCallClass = PyType_FromModuleAndSpec(
+        m, &LimitedVectorCallClass_spec, NULL);
+    if (!LimitedVectorCallClass) {
+        return -1;
+    }
+    if (PyModule_AddType(m, (PyTypeObject *)LimitedVectorCallClass) < 0) {
+        return -1;
+    }
+
+    return 0;
+}