diff --git a/Python/ast.c b/Python/ast.c
index fbce7d7..0506b47 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -2178,6 +2178,7 @@
     n = CHILD(n, 0);
     if (STR(CHILD(n, 0))[0] == 'i') { /* import */
         n = CHILD(n, 1);
+	REQ(n, dotted_as_names);
 	aliases = asdl_seq_new((NCH(n) + 1) / 2);
 	if (!aliases)
 		return NULL;