Index: Python/ceval.c
===================================================================
--- Python/ceval.c	(revision 61455)
+++ Python/ceval.c	(working copy)
@@ -4042,6 +4042,13 @@
 	}
 }
 
+#define Py3kExceptionClass_Check(x)					\
+	(PyType_Check((x)) &&						\
+	  PyType_FastSubclass((PyTypeObject*)(x), Py_TPFLAGS_BASE_EXC_SUBCLASS))
+
+#define CANNOT_CATCH_MSG "catching classes that do not inherit from "\
+			 "BaseException is not allowed in 3.x."
+
 static PyObject *
 cmp_outcome(int op, register PyObject *v, register PyObject *w)
 {
@@ -4079,6 +4086,15 @@
 					if (ret_val == -1)
 						return NULL;
 				}
+				if (Py_Py3kWarningFlag  &&
+					!Py3kExceptionClass_Check(exc)) {
+					int ret_val;
+					ret_val = PyErr_WarnEx(
+						PyExc_DeprecationWarning,
+						CANNOT_CATCH_MSG, 1);
+					if (ret_val == -1)
+						return NULL;
+				}
 			}
 		}
 		else {
@@ -4091,6 +4107,15 @@
 				if (ret_val == -1)
 					return NULL;
 			}
+			if (Py_Py3kWarningFlag  &&
+					!Py3kExceptionClass_Check(w)) {
+				int ret_val;
+				ret_val = PyErr_WarnEx(
+						PyExc_DeprecationWarning,
+						CANNOT_CATCH_MSG, 1);
+				if (ret_val == -1)
+					return NULL;
+			}
 		}
 		res = PyErr_GivenExceptionMatches(v, w);
 		break;