1 files changed, 2 insertions, 0 deletions
diff --git a/lib.c b/lib.c
index 9be90ea6..d6f44dad 100644
--- a/lib.c
+++ b/lib.c
@@ -5171,6 +5171,8 @@ static val lazy_stream_func(val env, val lcons)
 
 val lazy_stream_cons(val stream)
 {
+  stream = default_arg(stream, std_input);
+
   if (real_time_stream_p(stream)) {
     return make_lazy_cons(func_f1(stream, simple_lazy_stream_func));
   } else {