Index: Python/ast.c
===================================================================
--- Python/ast.c	(revision 61465)
+++ Python/ast.c	(working copy)
@@ -353,6 +353,14 @@
                 !strcmp(PyString_AS_STRING(e->v.Attribute.attr), "None")) {
                 return ast_error(n, "assignment to None");
             }
+            if (Py_Py3kWarningFlag &&
+                ctx == Store &&
+                (!strcmp(PyString_AS_STRING(e->v.Attribute.attr), "True") ||
+                !strcmp(PyString_AS_STRING(e->v.Attribute.attr), "False"))
+                ) {
+                PyErr_Warn(PyExc_DeprecationWarning, 
+                    "Assignment to True or False is forbidden in 3.x.");
+            }
             e->v.Attribute.ctx = ctx;
             break;
         case Subscript_kind:
@@ -363,6 +371,14 @@
                 !strcmp(PyString_AS_STRING(e->v.Name.id), "None")) {
                     return ast_error(n, "assignment to None");
             }
+            if (Py_Py3kWarningFlag &&
+                ctx == Store &&
+                (!strcmp(PyString_AS_STRING(e->v.Name.id), "True") ||
+                !strcmp(PyString_AS_STRING(e->v.Name.id), "False"))
+                ) {
+                PyErr_Warn(PyExc_DeprecationWarning, 
+                        "Assignment to True or False is forbidden in 3.x.");
+            }
             e->v.Name.ctx = ctx;
             break;
         case List_kind: