diff --git a/Objects/abstract.c b/Objects/abstract.c
index 63b2041..5eb7b28 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -111,8 +111,12 @@
 		return defaultvalue;
 	/* try o.__length_hint__() */
         hintmeth = _PyObject_LookupSpecial(o, "__length_hint__", &hintstrobj);
-	if (hintmeth == NULL)
-		return defaultvalue;
+	if (hintmeth == NULL) {
+		if (PyErr_Occurred())
+			return -1;
+		else
+			return defaultvalue;
+	}
 	ro = PyObject_CallFunctionObjArgs(hintmeth, NULL);
 	Py_DECREF(hintmeth);
 	if (ro == NULL) {
@@ -2945,6 +2949,8 @@
 			}
 			return ok;
 		}
+		else if (PyErr_Occurred())
+			return -1;
 	}
 	return recursive_isinstance(inst, cls);
 }
@@ -3021,6 +3027,9 @@
 			}
 			return ok;
 		}
+		else if (PyErr_Occurred()) {
+			return -1;
+		}
 	}
 	return recursive_issubclass(derived, cls);
 }