From 6c93fde85da027748bddd7cf75e295ed70ce3b05 Mon Sep 17 00:00:00 2001
From: Elizabeth Mattijsen <liz@wenzperl.nl>
Date: Mon, 17 Sep 2018 21:21:09 +0200
Subject: [PATCH] Make sure X handles empty lists on RHS

Fixes R#2286
---
 src/core/Rakudo/Iterator.pm6 | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/core/Rakudo/Iterator.pm6 b/src/core/Rakudo/Iterator.pm6
index 27ca8ce7a2b..13a82b0dc12 100644
--- a/src/core/Rakudo/Iterator.pm6
+++ b/src/core/Rakudo/Iterator.pm6
@@ -1133,18 +1133,18 @@ class Rakudo::Iterator {
 
                     # it's a List, may have a reified we can use directly
                     nqp::if(
-                      nqp::isnull(
+                      nqp::isconcrete(
                         $elem := nqp::getattr($elem,List,'$!reified')
-                      ) || nqp::iseq_i(nqp::elems($elem),0),
-
-                      # cross with an empty list is always an empty list
-                      (return Rakudo::Iterator.Empty),
+                      ) && nqp::isgt_i(nqp::elems($elem),0),
 
                       # use the available reified directly
                       nqp::stmts(
                         nqp::bindpos($!reifieds,$i,$elem),
                         nqp::atpos($elem,0)
-                      )
+                      ),
+
+                      # cross with an empty list is always an empty list
+                      (return Rakudo::Iterator.Empty)
                     ),
 
                     # need to set up an iterator