PyFunction_Call() did not check the result of PyObject_Repr() for NULL, and

should just avoid calling it in the first place to avoid waiting for a repr
of a large object like a dict or list.  The result of PyObject_Repr() was
being leaked as well.
Bugfix candidate!

Objects/abstract.c

@@ -1660,8 +1660,8 @@ PyObject_Call(PyObject *func, PyObject *arg, PyObject *kw)
 				"NULL result without error in PyObject_Call");
 		return result;
 	}
-	PyErr_Format(PyExc_TypeError, "object is not callable: %s",
+	PyErr_Format(PyExc_TypeError, "'%s' object is not callable",
-		     PyString_AS_STRING(PyObject_Repr(func)));
+		     func->ob_type->tp_name);
 	return NULL;
 }