src/Routing/Routes.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/Routing/Routes.php b/src/Routing/Routes.php
index fe1c76b..74aa762 100644
--- a/src/Routing/Routes.php
+++ b/src/Routing/Routes.php
@@ -351,7 +351,11 @@ class Routes implements ContainerInjectionInterface {
    *   array; FALSE otherwise.
    */
   protected static function hasNonInternalTargetResourceTypes(array $resource_types) {
-    return array_reduce($resource_types, function ($carry, ResourceType $target) {
+    return array_reduce($resource_types, function ($carry, $target) use ($resource_types) {
+      if ($target === NULL) {
+        var_dump($resource_types);
+        exit;
+      }
       return $carry || !$target->isInternal();
     }, FALSE);
   }