--- a/mercurial/parsers.c	Tue Aug 11 14:49:40 2015 -0400
+++ b/mercurial/parsers.c	Tue Aug 11 14:50:39 2015 -0400
@@ -1151,13 +1151,13 @@
 	/* Initialize internal datastructures */
 	tovisit = (int *)malloc((len + 1) * sizeof(int));
 	if (tovisit == NULL) {
-		PyErr_SetNone(PyExc_MemoryError);
+		PyErr_NoMemory();
 		goto release_reachable;
 	}
 
 	seen = (char *)calloc(len+1, 1);
 	if (seen == NULL) {
-		PyErr_SetNone(PyExc_MemoryError);
+		PyErr_NoMemory();
 		goto release_seen_and_tovisit;
 	}