diff -r 7ce459fc57b9 Lib/test/test_py3kwarn.py
--- a/Lib/test/test_py3kwarn.py	Thu Oct 02 11:36:01 2014 +0300
+++ b/Lib/test/test_py3kwarn.py	Thu Oct 02 20:33:10 2014 +0300
@@ -259,6 +259,14 @@ class TestPy3KWarnings(unittest.TestCase
             self.assertWarning(None, w,
                  "Overriding __eq__ blocks inheritance of __hash__ in 3.x")
             w.reset()
+            with warnings.catch_warnings():
+                warnings.filterwarnings("error")
+                with self.assertRaisesRegexp(DeprecationWarning,
+                        "Overriding __eq__ blocks inheritance of __hash__ in 3.x"):
+                    class WarnOnlyEq(object):
+                        def __eq__(self, other): pass
+            self.assertEqual(len(w.warnings), 0)
+            w.reset()
             class WarnCmpAndEq(object):
                 def __cmp__(self, other): pass
                 def __eq__(self, other): pass
diff -r 7ce459fc57b9 Objects/typeobject.c
--- a/Objects/typeobject.c	Thu Oct 02 11:36:01 2014 +0300
+++ b/Objects/typeobject.c	Thu Oct 02 20:33:10 2014 +0300
@@ -3769,7 +3769,7 @@ overrides_name(PyTypeObject *type, char 
 #define OVERRIDES_HASH(x)       overrides_name(x, "__hash__")
 #define OVERRIDES_EQ(x)         overrides_name(x, "__eq__")
 
-static void
+static int
 inherit_slots(PyTypeObject *type, PyTypeObject *base)
 {
     PyTypeObject *basebase;
@@ -3917,12 +3917,7 @@ inherit_slots(PyTypeObject *type, PyType
                                            "__eq__ blocks inheritance "
                                            "of __hash__ in 3.x",
                                            1) < 0)
-                            /* XXX This isn't right.  If the warning is turned
-                               into an exception, we should be communicating
-                               the error back to the caller, but figuring out
-                               how to clean up in that case is tricky.  See
-                               issue 8627 for more. */
-                            PyErr_Clear();
+                            return -1;
                     }
                 }
             }
@@ -3961,6 +3956,7 @@ inherit_slots(PyTypeObject *type, PyType
          * obvious to be done -- the type is on its own.
          */
     }
+    return 0;
 }
 
 static int add_operators(PyTypeObject *);
@@ -4070,7 +4066,8 @@ PyType_Ready(PyTypeObject *type)
     for (i = 1; i < n; i++) {
         PyObject *b = PyTuple_GET_ITEM(bases, i);
         if (PyType_Check(b))
-            inherit_slots(type, (PyTypeObject *)b);
+            if (inherit_slots(type, (PyTypeObject *)b) < 0)
+                goto error;
     }
 
     /* Sanity check for tp_free. */