diff --git a/Python/ceval.c b/Python/ceval.c
index 38ac509..38c9b52 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2684,8 +2684,9 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
         TARGET(BUILD_MAP_UNPACK) {
             int with_call = opcode == BUILD_MAP_UNPACK_WITH_CALL;
             int num_maps;
-            int function_location;
+            int function_location = 0;
             int i;
+            Py_ssize_t endsize = 0;
             PyObject *sum = PyDict_New();
             if (sum == NULL)
                 goto error;
@@ -2699,58 +2700,67 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 
             for (i = num_maps; i > 0; i--) {
                 PyObject *arg = PEEK(i);
-                if (with_call) {
-                    PyObject *intersection = _PyDictView_Intersect(sum, arg);
-
-                    if (intersection == NULL) {
+                if (with_call && !PyDict_CheckExact(arg)) {
+                    PyObject *newarg = PyDict_New();
+                    if (newarg == NULL) {
+                        goto map_unpack_error;
+                    }
+                    if (PyDict_Update(newarg, arg) < 0) {
                         if (PyErr_ExceptionMatches(PyExc_AttributeError)) {
-                            PyObject *func = (
-                                    PEEK(function_location + num_maps));
                             PyErr_Format(PyExc_TypeError,
-                                    "%.200s%.200s argument after ** "
-                                    "must be a mapping, not %.200s",
-                                    PyEval_GetFuncName(func),
-                                    PyEval_GetFuncDesc(func),
+                                    "'%.200s' object is not a mapping",
                                     arg->ob_type->tp_name);
                         }
-                        Py_DECREF(sum);
-                        goto error;
-                    }
-
-                    if (PySet_GET_SIZE(intersection)) {
-                        Py_ssize_t idx = 0;
-                        PyObject *key;
-                        PyObject *func = PEEK(function_location + num_maps);
-                        Py_hash_t hash;
-                        _PySet_NextEntry(intersection, &idx, &key, &hash);
-                        if (!PyUnicode_Check(key)) {
-                            PyErr_Format(PyExc_TypeError,
-                                    "%.200s%.200s keywords must be strings",
-                                    PyEval_GetFuncName(func),
-                                    PyEval_GetFuncDesc(func));
-                        } else {
-                            PyErr_Format(PyExc_TypeError,
-                                    "%.200s%.200s got multiple "
-                                    "values for keyword argument '%U'",
-                                    PyEval_GetFuncName(func),
-                                    PyEval_GetFuncDesc(func),
-                                    key);
-                        }
-                        Py_DECREF(intersection);
-                        Py_DECREF(sum);
-                        goto error;
+                        goto map_unpack_error;
                     }
-                    Py_DECREF(intersection);
+                    Py_DECREF(arg);
+                    SET_VALUE(i, newarg);
+                    arg = newarg;
                 }
-
                 if (PyDict_Update(sum, arg) < 0) {
                     if (PyErr_ExceptionMatches(PyExc_AttributeError)) {
                         PyErr_Format(PyExc_TypeError,
                                 "'%.200s' object is not a mapping",
                                 arg->ob_type->tp_name);
                     }
-                    Py_DECREF(sum);
-                    goto error;
+                    goto map_unpack_error;
+                }
+                if (with_call) {
+                    endsize += PyDict_Size(arg);
+                    if (endsize != PyDict_Size(sum)) {
+                        for (Py_ssize_t j = num_maps; j > i; j--) {
+                            PyObject *jth = PEEK(j);
+                            PyObject *intersection = _PyDictView_Intersect(arg, jth);
+                            if (intersection == NULL) {
+                                goto map_unpack_error;
+                            }
+
+                            if (PySet_GET_SIZE(intersection)) {
+                                Py_ssize_t idx = 0;
+                                PyObject *key;
+                                PyObject *func = PEEK(function_location + num_maps);
+                                Py_hash_t hash;
+                                _PySet_NextEntry(intersection, &idx, &key, &hash);
+                                if (!PyUnicode_Check(key)) {
+                                    PyErr_Format(PyExc_TypeError,
+                                            "%.200s%.200s keywords must be strings",
+                                            PyEval_GetFuncName(func),
+                                            PyEval_GetFuncDesc(func));
+                                } else {
+                                    PyErr_Format(PyExc_TypeError,
+                                            "%.200s%.200s got multiple "
+                                            "values for keyword argument '%U'",
+                                            PyEval_GetFuncName(func),
+                                            PyEval_GetFuncDesc(func),
+                                            key);
+                                }
+                                Py_DECREF(intersection);
+                                goto map_unpack_error;
+                            }
+                            Py_DECREF(intersection);
+
+                        }
+                    }
                 }
             }
 
@@ -2758,6 +2768,9 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
                 Py_DECREF(POP());
             PUSH(sum);
             DISPATCH();
+map_unpack_error:
+            Py_DECREF(sum);
+            goto error;
         }
 
         TARGET(MAP_ADD) {