diff --git a/source/bubel/ecs/manager.d b/source/bubel/ecs/manager.d
index d33f0ff..0a5e55a 100644
--- a/source/bubel/ecs/manager.d
+++ b/source/bubel/ecs/manager.d
@@ -1030,6 +1030,7 @@ export struct EntityManager
         foreach (caller; passes[pass].system_callers)
         {
             System* sys = &systems[caller.system_id];
+            assert(sys !is null);
             if (sys.enabled && sys.willExecute)
             {
                 if (sys.m_empty)
@@ -3235,6 +3236,8 @@ export struct EntityManager
         {
             if(!system.m_empty)
             {
+                assert(info !is null);
+                
                 EntitiesBlock* block;
                 if (first_block)
                     block = first_block;