diff -r 9c34ead53f94 Include/descrobject.h
--- a/Include/descrobject.h	Thu Dec 08 17:56:55 2011 +0000
+++ b/Include/descrobject.h	Sun Dec 11 14:27:47 2011 +0000
@@ -42,6 +42,7 @@
     PyObject_HEAD
     PyTypeObject *d_type;
     PyObject *d_name;
+    PyObject *d_qualname;
 } PyDescrObject;
 
 #define PyDescr_COMMON PyDescrObject d_common
diff -r 9c34ead53f94 Lib/test/test_sys.py
--- a/Lib/test/test_sys.py	Thu Dec 08 17:56:55 2011 +0000
+++ b/Lib/test/test_sys.py	Sun Dec 11 14:27:47 2011 +0000
@@ -670,17 +670,17 @@
         # complex
         check(complex(0,1), size(h + '2d'))
         # method_descriptor (descriptor object)
-        check(str.lower, size(h + '2PP'))
+        check(str.lower, size(h + '3PP'))
         # classmethod_descriptor (descriptor object)
         # XXX
         # member_descriptor (descriptor object)
         import datetime
-        check(datetime.timedelta.days, size(h + '2PP'))
+        check(datetime.timedelta.days, size(h + '3PP'))
         # getset_descriptor (descriptor object)
         import collections
-        check(collections.defaultdict.default_factory, size(h + '2PP'))
+        check(collections.defaultdict.default_factory, size(h + '3PP'))
         # wrapper_descriptor (descriptor object)
-        check(int.__add__, size(h + '2P2P'))
+        check(int.__add__, size(h + '3P2P'))
         # method-wrapper (descriptor object)
         check({}.__iter__, size(h + '2P'))
         # dict
diff -r 9c34ead53f94 Objects/descrobject.c
--- a/Objects/descrobject.c	Thu Dec 08 17:56:55 2011 +0000
+++ b/Objects/descrobject.c	Sun Dec 11 14:27:47 2011 +0000
@@ -9,6 +9,7 @@
     _PyObject_GC_UNTRACK(descr);
     Py_XDECREF(descr->d_type);
     Py_XDECREF(descr->d_name);
+    Py_XDECREF(descr->d_qualname);
     PyObject_GC_Del(descr);
 }
 
@@ -321,6 +322,52 @@
     return PyUnicode_FromString(descr->d_method->ml_doc);
 }
 
+static PyObject *
+calculate_qualname(PyDescrObject *descr)
+{
+    static PyObject *qualname = NULL;
+    PyObject *type_qualname, *res;
+
+    if (qualname == NULL) {
+        qualname = PyUnicode_InternFromString("__qualname__");
+        if (qualname == NULL)
+            return NULL;
+    }
+
+    if (descr->d_name == NULL || !PyUnicode_Check(descr->d_name)) {
+        PyErr_SetString(PyExc_AssertionError,
+                        "<descriptor>.__name__ is not a unicode object");
+        return NULL;
+    }
+
+    if (descr->d_type == NULL) {
+        PyErr_SetString(PyExc_AssertionError,
+                        "<descriptor>.__objclass__ is null");
+        return NULL;
+    }
+
+    type_qualname = PyObject_GetAttr((PyObject *)descr->d_type, qualname);
+    if (type_qualname == NULL || !PyUnicode_Check(type_qualname)) {
+        PyErr_SetString(PyExc_AssertionError, "<descriptor>.__objclass__."
+                        "__qualname__ is not a unicode object");
+        Py_XDECREF(type_qualname);
+        return NULL;
+    }
+
+    res = PyUnicode_FromFormat("%S.%S", type_qualname, descr->d_name);
+    Py_DECREF(type_qualname);
+    return res;
+}
+
+static PyObject *
+descr_get_qualname(PyDescrObject *descr)
+{
+    if (descr->d_qualname == NULL)
+        descr->d_qualname = calculate_qualname(descr);
+    Py_XINCREF(descr->d_qualname);
+    return descr->d_qualname;
+}
+
 static PyMemberDef descr_members[] = {
     {"__objclass__", T_OBJECT, offsetof(PyDescrObject, d_type), READONLY},
     {"__name__", T_OBJECT, offsetof(PyDescrObject, d_name), READONLY},
@@ -329,6 +376,7 @@
 
 static PyGetSetDef method_getset[] = {
     {"__doc__", (getter)method_get_doc},
+    {"__qualname__", (getter)descr_get_qualname},
     {0}
 };
 
@@ -344,6 +392,7 @@
 
 static PyGetSetDef member_getset[] = {
     {"__doc__", (getter)member_get_doc},
+    {"__qualname__", (getter)descr_get_qualname},
     {0}
 };
 
@@ -359,6 +408,7 @@
 
 static PyGetSetDef getset_getset[] = {
     {"__doc__", (getter)getset_get_doc},
+    {"__qualname__", (getter)descr_get_qualname},
     {0}
 };
 
@@ -374,6 +424,7 @@
 
 static PyGetSetDef wrapperdescr_getset[] = {
     {"__doc__", (getter)wrapperdescr_get_doc},
+    {"__qualname__", (getter)descr_get_qualname},
     {0}
 };
 
@@ -585,6 +636,7 @@
             Py_DECREF(descr);
             descr = NULL;
         }
+        descr->d_qualname = NULL;
     }
     return descr;
 }
@@ -987,9 +1039,16 @@
     }
 }
 
+static PyObject *
+wrapper_qualname(wrapperobject *wp)
+{
+    return descr_get_qualname((PyDescrObject *)wp->descr);
+}
+
 static PyGetSetDef wrapper_getsets[] = {
     {"__objclass__", (getter)wrapper_objclass},
     {"__name__", (getter)wrapper_name},
+    {"__qualname__", (getter)wrapper_qualname},
     {"__doc__", (getter)wrapper_doc},
     {0}
 };