diff --git a/source/blender/editors/space_outliner/outliner_intern.hh b/source/blender/editors/space_outliner/outliner_intern.hh
index b9ffea7c735..a9bdcc56787 100644
--- a/source/blender/editors/space_outliner/outliner_intern.hh
+++ b/source/blender/editors/space_outliner/outliner_intern.hh
@@ -219,8 +219,9 @@ typedef enum {
 
 /* is the current element open? if so we also show children */
 #define TSELEM_OPEN(telm, sv) \
-  (((telm)->flag & TSE_CLOSED) == 0 || \
-   (SEARCHING_OUTLINER(sv) && ((telm)->flag & TSE_CHILDSEARCH)))
+  (CHECK_TYPE_INLINE(telm, TreeStoreElem *), \
+   (((telm)->flag & TSE_CLOSED) == 0 || \
+    (SEARCHING_OUTLINER(sv) && ((telm)->flag & TSE_CHILDSEARCH))))
 
 /**
  * Container to avoid passing around these variables to many functions.