diff --git a/src/scanner.c b/src/scanner.c
index da8adea4..c512d231 100644
--- a/src/scanner.c
+++ b/src/scanner.c
@@ -1634,7 +1634,9 @@ emit_header(struct protocol *protocol, enum side side)
 		*p = i->name;
 	}
 
-	qsort(types.data, types.size / sizeof *p, sizeof *p, cmp_names);
+	if (types.size > 0)
+		qsort(types.data, types.size / sizeof *p, sizeof *p, cmp_names);
+
 	prev = NULL;
 	wl_array_for_each(p, &types) {
 		if (prev && strcmp(*p, prev) == 0)
@@ -1844,7 +1846,10 @@ emit_code(struct protocol *protocol, enum visibility vis)
 		emit_types_forward_declarations(protocol, &i->request_list, &types);
 		emit_types_forward_declarations(protocol, &i->event_list, &types);
 	}
-	qsort(types.data, types.size / sizeof *p, sizeof *p, cmp_names);
+
+	if (types.size > 0)
+		qsort(types.data, types.size / sizeof *p, sizeof *p, cmp_names);
+
 	prev = NULL;
 	wl_array_for_each(p, &types) {
 		if (prev && strcmp(*p, prev) == 0)