diff --git a/Python/ast.c b/Python/ast.c
index ca832aa..b356192 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -2197,6 +2197,8 @@
             }
             else {
                 alias_ty a = alias_for_import_name(c, CHILD(n, 0));
+                if (!a)
+                    return NULL;
                 if (strcmp(STR(CHILD(n, 1)), "as") != 0) {
                     ast_error(n, "must use 'as' in import");
                     return NULL;