diff -r ae6813d21859 Modules/_ctypes/_ctypes.c
--- a/Modules/_ctypes/_ctypes.c	Thu Sep 22 11:43:46 2016 +0300
+++ b/Modules/_ctypes/_ctypes.c	Fri Sep 23 22:25:22 2016 +0300
@@ -3250,7 +3250,10 @@
         /* Here ftuple is a borrowed reference */
         return NULL;
 
-    if (!PyArg_ParseTuple(ftuple, "O&O", _get_name, &name, &dll)) {
+    if (!PyArg_ParseTuple(ftuple,
+                          "O&O;PyCFuncPtr.__new__: illegal function name and "
+                          "dll object sequence argument",
+                          _get_name, &name, &dll)) {
         Py_DECREF(ftuple);
         return NULL;
     }
diff -r ae6813d21859 Modules/_io/textio.c
--- a/Modules/_io/textio.c	Thu Sep 22 11:43:46 2016 +0300
+++ b/Modules/_io/textio.c	Fri Sep 23 22:25:22 2016 +0300
@@ -569,8 +569,11 @@
     PyObject *buffer;
     unsigned long long flag;
 
-    if (!PyArg_ParseTuple(state, "OK", &buffer, &flag))
+    if (!PyArg_ParseTuple(state,
+                          "OK;IncrementalNewlineDecoder.setstate: illegal "
+                          "state argument", &buffer, &flag)) {
         return NULL;
+    }
 
     self->pendingcr = (int) (flag & 1);
     flag >>= 1;
diff -r ae6813d21859 Modules/audioop.c
--- a/Modules/audioop.c	Thu Sep 22 11:43:46 2016 +0300
+++ b/Modules/audioop.c	Fri Sep 23 22:25:22 2016 +0300
@@ -1365,9 +1365,10 @@
         }
         for (chan = 0; chan < nchannels; chan++) {
             if (!PyArg_ParseTuple(PyTuple_GetItem(samps, chan),
-                                  "ii:ratecv", &prev_i[chan],
-                                               &cur_i[chan]))
+                                  "ii;audioop.ratecv: illegal state argument",
+                                  &prev_i[chan], &cur_i[chan])) {
                 goto exit;
+            }
         }
     }
 
@@ -1638,7 +1639,9 @@
         PyErr_SetString(PyExc_TypeError, "state must be a tuple or None");
         return NULL;
     }
-    else if (!PyArg_ParseTuple(state, "ii", &valpred, &index)) {
+    else if (!PyArg_ParseTuple(state,
+                               "ii;audioop.lin2adpcm: illegal state argument",
+                               &valpred, &index)) {
         return NULL;
     }
     else if (valpred >= 0x8000 || valpred < -0x8000 ||
@@ -1766,7 +1769,9 @@
         PyErr_SetString(PyExc_TypeError, "state must be a tuple or None");
         return NULL;
     }
-    else if (!PyArg_ParseTuple(state, "ii", &valpred, &index)) {
+    else if (!PyArg_ParseTuple(state,
+                               "ii;audioop.adpcm2lin: illegal state argument",
+                               &valpred, &index)) {
         return NULL;
     }
     else if (valpred >= 0x8000 || valpred < -0x8000 ||
diff -r ae6813d21859 Modules/itertoolsmodule.c
--- a/Modules/itertoolsmodule.c	Thu Sep 22 11:43:46 2016 +0300
+++ b/Modules/itertoolsmodule.c	Fri Sep 23 22:25:22 2016 +0300
@@ -147,8 +147,11 @@
 groupby_setstate(groupbyobject *lz, PyObject *state)
 {
     PyObject *currkey, *currvalue, *tgtkey;
-    if (!PyArg_ParseTuple(state, "OOO", &currkey, &currvalue, &tgtkey))
+    if (!PyArg_ParseTuple(state,
+                          "OOO;groupby.__setstate__: illegal state argument",
+                          &currkey, &currvalue, &tgtkey)) {
         return NULL;
+    }
     Py_INCREF(currkey);
     Py_XSETREF(lz->currkey, currkey);
     Py_INCREF(currvalue);
@@ -727,8 +730,11 @@
 {
     teedataobject *tdo;
     int index;
-    if (!PyArg_ParseTuple(state, "O!i", &teedataobject_type, &tdo, &index))
+    if (!PyArg_ParseTuple(state,
+                          "O!i;_tee.__setstate__: illegal state argument",
+                          &teedataobject_type, &tdo, &index)) {
         return NULL;
+    }
     if (index < 0 || index > LINKCELLS) {
         PyErr_SetString(PyExc_ValueError, "Index out of range");
         return NULL;
@@ -972,8 +978,11 @@
     PyObject *saved=NULL;
     int firstpass;
 
-    if (!PyArg_ParseTuple(state, "O!i", &PyList_Type, &saved, &firstpass))
+    if (!PyArg_ParseTuple(state,
+                          "O!i;cycle.__setstate__: illegal state argument",
+                          &PyList_Type, &saved, &firstpass)) {
         return NULL;
+    }
     Py_INCREF(saved);
     Py_XSETREF(lz->saved, saved);
     lz->firstpass = firstpass != 0;
@@ -1903,8 +1912,11 @@
 {
     PyObject *source, *active=NULL;
 
-    if (! PyArg_ParseTuple(state, "O|O", &source, &active))
+    if (!PyArg_ParseTuple(state,
+                          "O|O;chain.__setstate__: illegal state argument",
+                          &source, &active)) {
         return NULL;
+    }
 
     Py_INCREF(source);
     Py_XSETREF(lz->source, source);
@@ -3262,10 +3274,12 @@
     PyObject *indices, *cycles, *result;
     Py_ssize_t n, i;
 
-    if (!PyArg_ParseTuple(state, "O!O!",
-                          &PyTuple_Type, &indices,
-                          &PyTuple_Type, &cycles))
+    if (!PyArg_ParseTuple(state,
+                          "O!O!;permutations.__setstate__: illegal state "
+                          "argument", &PyTuple_Type, &indices,
+                          &PyTuple_Type, &cycles)) {
         return NULL;
+    }
 
     n = PyTuple_GET_SIZE(po->pool);
     if (PyTuple_GET_SIZE(indices) != n || PyTuple_GET_SIZE(cycles) != po->r) {
diff -r ae6813d21859 Modules/overlapped.c
--- a/Modules/overlapped.c	Thu Sep 22 11:43:46 2016 +0300
+++ b/Modules/overlapped.c	Fri Sep 23 22:25:22 2016 +0300
@@ -990,7 +990,9 @@
         ((SOCKADDR_IN*)Address)->sin_port = htons(Port);
         return Length;
     }
-    else if (PyArg_ParseTuple(obj, "uHkk", &Host, &Port, &FlowInfo, &ScopeId))
+    else if (PyArg_ParseTuple(obj,
+                              "uHkk;ConnectEx: illegal address_as_bytes "
+                              "argument", &Host, &Port, &FlowInfo, &ScopeId))
     {
         PyErr_Clear();
         Address->sa_family = AF_INET6;
diff -r ae6813d21859 Modules/socketmodule.c
--- a/Modules/socketmodule.c	Thu Sep 22 11:43:46 2016 +0300
+++ b/Modules/socketmodule.c	Fri Sep 23 22:25:22 2016 +0300
@@ -6079,12 +6079,14 @@
                         "getnameinfo() argument 1 must be a tuple");
         return NULL;
     }
-    if (!PyArg_ParseTuple(sa, "si|II",
-                          &hostp, &port, &flowinfo, &scope_id))
+    if (!PyArg_ParseTuple(sa,
+                          "si|II;getnameinfo: illegal sockaddr argument",
+                          &hostp, &port, &flowinfo, &scope_id)) {
         return NULL;
+    }
     if (flowinfo > 0xfffff) {
         PyErr_SetString(PyExc_OverflowError,
-                        "getsockaddrarg: flowinfo must be 0-1048575.");
+                        "getnameinfo: flowinfo must be 0-1048575.");
         return NULL;
     }
     PyOS_snprintf(pbuf, sizeof(pbuf), "%d", port);