diff --git a/gc.c b/gc.c
index 9ee8714878..4c32c5a1ed 100644
--- a/gc.c
+++ b/gc.c
@@ -2427,6 +2427,8 @@ gc_location_internal(void *objspace, VALUE value)
         return value;
     }
 
+    GC_ASSERT(rb_gc_impl_pointer_to_heap_p(objspace, (void *)value));
+
     return rb_gc_impl_location(objspace, value);
 }